Endovascular clot retrieval for acute ischaemic stroke in New Zealand
View Article PDF
Stroke endovascular clot retrieval (ECR) for patients with large proximal intracranial artery occlusion has been shown to improve clinical outcomes.1–5 An individual patient level meta-analysis of five large randomised-controlled trials showed that for every 2.6 patients treated with ECR, one had a reduction in the modified Rankin Scale (mRS) score of least one point, compared with standard therapy.6 For every five patients treated with ECR, one more is functionally independent (mRS 0–2). ECR increases quality of life and is highly cost effective.7,8
ECR is time critical, technically challenging and needs to be available 24 hours per day to avoid treatment gaps. Auckland City, Wellington Regional and Christchurch hospitals are the only ones in New Zealand with the resources to provide this therapy at present, and only Auckland provides a 24-hour service. A regional treatment pathway has been developed in the Northern and Midland regions with patients transferred to Auckland for this therapy. Similar pathways centred on Wellington and Christchurch are being developed. The aim of this study was to determine if ECR is being delivered in a safe and effective manner.
Methods
Stroke ECR has been performed in New Zealand since 2011,9 with early patients treated as part of the Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial (EXTEND-IA) trial,2 and more recent patients enrolled in the follow-on EXTEND-IA Tenectoplase (EXTEND-IA TNK) and EXTEND-IA TNK2 studies.10 All ECR patients are entered into the New Zealand Thrombolysis Register, which is under the auspices of the National Stroke Network.11 Patients had to be previously independent and have large proximal intracranial arterial occlusion. Patients were treated with 0.9mg/kg alteplase or 0.25mg/kg tenecteplase for those patients enrolled in the EXTEND-IA TNK trial, if indicated.
Anterior circulation strokes are those with distal internal carotid artery (ICA) or M1/proximal M2 segment of the middle cerebral artery (MCA) occlusion. Posterior circulation strokes are those with occlusion of the basilar (BA), intracranial vertebral (VA) or posterior cerebral (PCA) arteries. Most anterior circulation patients were treated within six hours, and posterior circulation patients treated within 24 hours, of symptom onset. The neuro-interventionists used either a Solitaire FR (Covidien) or Trevo (Stryker) stent retriever and/or aspiration thrombectomy. A minority of patients required angioplasty and stenting of the ICA or MCA M1 during the procedure. The neuro-interventionist and anaesthetist decided on the use of a general anaesthetic or conscious sedation in each case. Recanalisation was determined using the Thrombolysis in Cerebral Infarction (TICI) scores where TICI3 is complete recanalisation and TICI2b is restoration of flow to greater than 50% of the affected territory.12
The National Institutes of Health Stroke Scale (NIHSS) was used to assess baseline and 24-hour stroke severity. The NIHSS ranges from 0 (normal) to 42 (dead). Early neurologic recovery was defined as either a decrease in NIHSS of ≥8 or a score of 0–1, at 24 hours. The mRS at day 90 was used to determine functional outcomes with 0 normal, 0–2 defined as functionally independent, 4–5 as significantly dependent, and 6 as dead. All adverse outcomes were recorded, with particular focus on symptomatic intracranial haemorrhage (sICH) and death. sICH was defined as parenchymal haemorrhage occupying >30% of the infarct volume and with significant mass effect on CT, and a reduction in NIHSS at 24 hours by ≥4.13
Results
Three hundred and twelve patients [136 women, mean (range) age of 64 (16–92) years] with ischaemic stroke from 11 DHBs have been treated with ECR in New Zealand between 2011 and the end of April 2018 (Table 1). Two hundred and forty-one patients were treated at Auckland City hospital, 57 at Christchurch hospital and 14 at Wellington hospital. There were 260 (83%) with anterior and 52 (17%) with posterior circulation occlusion. Thirty (10%) patients had a stroke while already in hospital and 157 (50%) were transferred to an ECR centre from another hospital. One hundred and seventy-six (56%) were admitted out-of-hours (Monday to Friday 17:00 to 08:00, and all day in weekends and holidays). One hundred and ninety-four (62%) were treated with IV alteplase prior to ECR. Day 90 mRS data was available for 227 of 252 (90%) patients treated before 31 January 2018.
Table 1: Results.
*New Zealand Ministry of Health Level 1 Ethnic Groups, and includes South Asians.
†Internal carotid artery (ICA), includes one bilateral occlusion, denominator 261.
‡First division of middle cerebral artery (M1).
§Second division of middle cerebral artery (M2).
‖Includes one vertebral artery occlusion and one posterior cerebral artery occlusion.
¶Endovascular clot retrieval (ECR).
**Thrombolysis in Cerebral Infarction (TICI).
††National Institute of Health Stroke Scale (NIHSS).
‡‡Modified Rankin Scale (mRS).
Anterior circulation occlusion patients
The 260 anterior circulation patients had baseline median (range) NIHSS scores of 18 (3–40), indicating severe disability. One hundred and seventy-two patients (66%) were treated with intravenous alteplase with a time from stroke onset to alteplase bolus of 123 minutes. One hundred and twenty-four (48%) patients were transferred to an ECR centre from a ‘home DHB’. The time from stroke onset to groin puncture was 200 minutes and ECR was completed by 261 minutes. Two hundred and twelve of 247 (86%) anterior circulation patients had ECR under GA and 29 of 257 (11%) required ICU admission following the procedure.
Complete or near complete recanalisation (TICI3 and TICI2b) was seen in 218 of 253 (86%) anterior circulation patients where this information was recorded. Early neurological recovery was seen in 109 of 231 (47%) patients. Day 90 mRS data was available for 176 (68%) patients, of whom 97 (55%) were functionally independent, 18 (10%) were severely dependent and 35 (20%) were dead. sICH occurred in 9 of 257 (4%) patients. The median length of stay in all healthcare facilities was eight days.
Posterior circulation occlusion patients
The 52 posterior circulation patients had a baseline median (range) NIHSS score of 20 (3–38), indicating severe disability. Twenty-two patients (42%) were treated with intravenous alteplase with a time from stroke onset to alteplase bolus of 148 minutes. Thirty-three (63%) patients were transferred to an ECR centre from a ‘home DHB’. The time from stroke onset to groin puncture was 266 minutes, and ECR was completed by 345 minutes. Fifty-one (98%) of posterior circulation patients had ECR under GA and 36 (70%) required ICU admission following the procedure. Complete or near-complete recanalisation was achieved in 42 of 47 (89%) patients. Early neurologic recovery was seen in 19 of 39 (49%) patients where this information is recorded. Day 90 mRS data was available for 47 patients, of whom 19 (40%) were functionally independent, eight (17%) were severely dependent and 14 (30%) were dead. sICH occurred in 2 of 50 (4%) patients. The median length of stay in all healthcare facilities was seven days.
Discussion
This study has found that stroke endovascular clot retrieval is being implemented in a safe and effective manner in New Zealand. Anterior circulation patients had a complete or near-complete recanalisation rate of 86%, and 55% of patients were functionally independent at three months. This compares with a large meta-analysis where 71% had complete or near complete recanalisation and 46% of patients were functionally independent.6 The onset to ECR completion time was also similar at 261 minutes in New Zealand compared to 285 minutes. The New Zealand mortality rates were higher at 20% versus 15% but our numbers are relatively small and patients had higher baseline NIHSS scores. The number of treated patients has grown exponentially from 30 in 2015 to 133 in 2017, with 250 patients projected for 2018.
Randomised-controlled trials of ECR in patients with occlusion of the basilar or posterior cerebral arteries are still underway. However, the use of ECR is considered reasonable for carefully selected patients,14 with a treatment window of up to 24 hours after symptom onset in Australian and New Zealand guidelines.15 In this study, basilar occlusion patients were severely disabled at baseline and had longer times to ECR completion than the anterior circulation patients. Basilar occlusion patients were also less likely to be functionally independent (40%), and had a higher mortality rate (30%) at three months. However, basilar occlusion patients receiving standard therapy alone have mortality rates as high as 80%.16
Endovascular clot retrieval is cost effective. A UK study reported upfront costs are high but quality-adjusted life expectancy is improved, and clot retrieval has a 100% probability of being cost effective at the minimum willingness to pay.17 The Australia/New Zealand EXTEND IA study, which provides important ‘local’ data, showed that the costs of consumables, staffing and inter-hospital transfer were offset by significantly shorter hospital stays.7 Clot retrieval patients spent a median of 73 (IQR 47–86) of the first 90 days at home, compared with only 15 (IQR 0–69) days in the standard care patients (p=0.006). There are also societal savings resulting from more people being independent and avoiding long-term care.
This study has a number of limitations. No resources are provided to maintain the database and we were dependent on the local centres recording all ECR patients and entering the data accurately. Outcome measures were not determined by an independent assessor. Follow-up data was missing in 10% of patients, reflecting the fact that many patients are transferred to home DHBs for ongoing care. This study highlights important achievements in the provision of ECR services in New Zealand. The numbers of ECR patients has grown, reflecting an expansion of services, with patients from 11 DHBs now treated, compared with only four prior to 2015. However, three quarters of the patients were treated at a single centre with major discrepancies in service provision across the country. Treatment figures per centre are due in part to differences in metropolitan population catchment areas, and there is still significant work required to fully implement regional treatment pathways in the Midland, Central and South Island regions. The DAWN and DEFUSE 3 studies have shown benefit in treating patients up to 24 hours, and 12 of the 312 patients were treated in this extended window.18,19 Patient selection beyond six hours requires advanced imaging that is currently available at only four large urban hospitals.
To meet these challenges, the Ministry of Health has established a National ECR Service Improvement Programme to help facilitate implementation efforts. Ongoing regional, inter-regional and inter-sector collaboration will be essential to implement comprehensive and equitable ECR services across all of New Zealand.
Summary
Abstract
Aim
Stroke endovascular clot retrieval (ECR) in patients with large proximal vessel occlusion improves clinical outcomes. We present the New Zealand ECR experience.
Method
All New Zealand patients treated with ECR since 2011 were included. Patients were considered eligible if they were independent prior to stroke and had proximal intracranial arterial occlusion.
Results
Three hundred and twelve patients [136 women, mean (SD) age of 64 (17) years] from 11 district health boards have been treated between March 2011 and April 2018. There were 260 (83%) patients with anterior and 52 (17%) with posterior circulation arterial occlusion. One hundred and ninety-three (62%) patients were pre-treated with intravenous alteplase. The median time from symptom onset to groin puncture was 210 (range 65-985) minutes. Complete or near-complete recanalisation (Thrombolysis in Cerebral Infarction scores of 3 or 2b) was achieved in 260 of 300 (87%) and the National Institutes of Health Stroke Scale score improved from a median of 18 at baseline to 7 at 24 hours. By day 90, 55% of the anterior circulation patients and 40% of the posterior circulation patients were living independently at home. Mortality rates were 20% for anterior circulation patients and 30% for the posterior circulation patients.
Conclusion
This study has shown that stroke endovascular clot retrieval is being provided safely and effectively in New Zealand. However, there remain discrepancies in service provision, and ongoing regional, inter-regional and inter-sector collaboration is essential to implement comprehensive and equitable ECR services across the country.
Author Information
Acknowledgements
Correspondence
Correspondence Email
Competing Interests
- Berkhemer OA, Fransen PS, Beumer D, et al. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med 2015; 372:11–20.
- Campbell BC, Mitchell PJ, Kleinig TJ, et al. Endovascular therapy for ischemic stroke with perfusion-imaging selection. N Engl J Med 2015; 372:1009–18.
- Goyal M, Demchuk AM, Menon BK, et al. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med 2015; 372:1019–30.
- Saver JL, Goyal M, Bonafe A, et al. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med 2015; 372:2285–95.
- Jovin TG, Chamorro A, Cobo E, et al. Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med 2015; 372:2296–306.
- Goyal M, Menon BK, van Zwam WH, et al. Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis of individual patient data from five randomised trials. Lancet 2016; 387:1723–31.
- Campbell BCV, Mitchell PJ, Churilov L, et al. Endovascular Thrombectomy for Ischemic Stroke Increases Disability-Free Survival, Quality of Life, and Life Expectancy and Reduces Cost. Front Neurol 2017; 8:657.
- Aronsson M, Persson J, Blomstrand C, Wester P, Levin LA. Cost-effectiveness of endovascular thrombectomy in patients with acute ischemic stroke. Neurology 2016; 86:1053–9.
- Barber PA, Liu Q, Brew S, et al. Endovascular clot retrieval for acute ischaemic stroke: the Auckland City Hospital experience. NZ Med J 2015; 128:57–62.
- Campbell BCV, Mitchell PJ, Churilov L, et al. Tenecteplase versus Alteplase before Thrombectomy for Ischemic Stroke. N Engl J Med 2018; 378:1573–82.
- Liu Q, Ranta AA, Abernethy G, Barber PA. Trends in New Zealand stroke thrombolysis treatment rates. NZ Med J 2017; 130:50–6.
- Higashida RT, Furlan AJ, Roberts H, et al. Trial design and reporting standards for intra-arterial cerebral thrombolysis for acute ischemic stroke. Stroke 2003; 34:e109–37.
- Wahlgren N, Ahmed N, Davalos A, et al. Thrombolysis with alteplase for acute ischaemic stroke in the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST): an observational study. Lancet 2007; 369:275–82.
- Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke 2018; 49:e46–e110.
- Australian Stroke Foundation. Clinical Guidelines for Stroke Management 2017. Melbourne, Australia 2017.
- Schonewille WJ, Wijman CA, Michel P, et al. Treatment and outcomes of acute basilar artery occlusion in the Basilar Artery International Cooperation Study (BASICS): a prospective registry study. Lancet Neurol 2009; 8:724–30.
- Ganesalingam J, Pizzo E, Morris S, Sunderland T, Ames D, Lobotesis K. Cost-Utility Analysis of Mechanical Thrombectomy Using Stent Retrievers in Acute Ischemic Stroke. Stroke 2015; 46:2591–8.
- Jovin TG, Nogueira RG, Investigators D. Thrombectomy 6 to 24 Hours after Stroke. N Engl J Med 2018; 378:1161–2.
- Albers GW, Marks MP, Kemp S, et al. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med 2018; 378:708–18.
For the PDF of this article,
contact nzmj@nzma.org.nz
View Article PDF
Stroke endovascular clot retrieval (ECR) for patients with large proximal intracranial artery occlusion has been shown to improve clinical outcomes.1–5 An individual patient level meta-analysis of five large randomised-controlled trials showed that for every 2.6 patients treated with ECR, one had a reduction in the modified Rankin Scale (mRS) score of least one point, compared with standard therapy.6 For every five patients treated with ECR, one more is functionally independent (mRS 0–2). ECR increases quality of life and is highly cost effective.7,8
ECR is time critical, technically challenging and needs to be available 24 hours per day to avoid treatment gaps. Auckland City, Wellington Regional and Christchurch hospitals are the only ones in New Zealand with the resources to provide this therapy at present, and only Auckland provides a 24-hour service. A regional treatment pathway has been developed in the Northern and Midland regions with patients transferred to Auckland for this therapy. Similar pathways centred on Wellington and Christchurch are being developed. The aim of this study was to determine if ECR is being delivered in a safe and effective manner.
Methods
Stroke ECR has been performed in New Zealand since 2011,9 with early patients treated as part of the Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial (EXTEND-IA) trial,2 and more recent patients enrolled in the follow-on EXTEND-IA Tenectoplase (EXTEND-IA TNK) and EXTEND-IA TNK2 studies.10 All ECR patients are entered into the New Zealand Thrombolysis Register, which is under the auspices of the National Stroke Network.11 Patients had to be previously independent and have large proximal intracranial arterial occlusion. Patients were treated with 0.9mg/kg alteplase or 0.25mg/kg tenecteplase for those patients enrolled in the EXTEND-IA TNK trial, if indicated.
Anterior circulation strokes are those with distal internal carotid artery (ICA) or M1/proximal M2 segment of the middle cerebral artery (MCA) occlusion. Posterior circulation strokes are those with occlusion of the basilar (BA), intracranial vertebral (VA) or posterior cerebral (PCA) arteries. Most anterior circulation patients were treated within six hours, and posterior circulation patients treated within 24 hours, of symptom onset. The neuro-interventionists used either a Solitaire FR (Covidien) or Trevo (Stryker) stent retriever and/or aspiration thrombectomy. A minority of patients required angioplasty and stenting of the ICA or MCA M1 during the procedure. The neuro-interventionist and anaesthetist decided on the use of a general anaesthetic or conscious sedation in each case. Recanalisation was determined using the Thrombolysis in Cerebral Infarction (TICI) scores where TICI3 is complete recanalisation and TICI2b is restoration of flow to greater than 50% of the affected territory.12
The National Institutes of Health Stroke Scale (NIHSS) was used to assess baseline and 24-hour stroke severity. The NIHSS ranges from 0 (normal) to 42 (dead). Early neurologic recovery was defined as either a decrease in NIHSS of ≥8 or a score of 0–1, at 24 hours. The mRS at day 90 was used to determine functional outcomes with 0 normal, 0–2 defined as functionally independent, 4–5 as significantly dependent, and 6 as dead. All adverse outcomes were recorded, with particular focus on symptomatic intracranial haemorrhage (sICH) and death. sICH was defined as parenchymal haemorrhage occupying >30% of the infarct volume and with significant mass effect on CT, and a reduction in NIHSS at 24 hours by ≥4.13
Results
Three hundred and twelve patients [136 women, mean (range) age of 64 (16–92) years] with ischaemic stroke from 11 DHBs have been treated with ECR in New Zealand between 2011 and the end of April 2018 (Table 1). Two hundred and forty-one patients were treated at Auckland City hospital, 57 at Christchurch hospital and 14 at Wellington hospital. There were 260 (83%) with anterior and 52 (17%) with posterior circulation occlusion. Thirty (10%) patients had a stroke while already in hospital and 157 (50%) were transferred to an ECR centre from another hospital. One hundred and seventy-six (56%) were admitted out-of-hours (Monday to Friday 17:00 to 08:00, and all day in weekends and holidays). One hundred and ninety-four (62%) were treated with IV alteplase prior to ECR. Day 90 mRS data was available for 227 of 252 (90%) patients treated before 31 January 2018.
Table 1: Results.
*New Zealand Ministry of Health Level 1 Ethnic Groups, and includes South Asians.
†Internal carotid artery (ICA), includes one bilateral occlusion, denominator 261.
‡First division of middle cerebral artery (M1).
§Second division of middle cerebral artery (M2).
‖Includes one vertebral artery occlusion and one posterior cerebral artery occlusion.
¶Endovascular clot retrieval (ECR).
**Thrombolysis in Cerebral Infarction (TICI).
††National Institute of Health Stroke Scale (NIHSS).
‡‡Modified Rankin Scale (mRS).
Anterior circulation occlusion patients
The 260 anterior circulation patients had baseline median (range) NIHSS scores of 18 (3–40), indicating severe disability. One hundred and seventy-two patients (66%) were treated with intravenous alteplase with a time from stroke onset to alteplase bolus of 123 minutes. One hundred and twenty-four (48%) patients were transferred to an ECR centre from a ‘home DHB’. The time from stroke onset to groin puncture was 200 minutes and ECR was completed by 261 minutes. Two hundred and twelve of 247 (86%) anterior circulation patients had ECR under GA and 29 of 257 (11%) required ICU admission following the procedure.
Complete or near complete recanalisation (TICI3 and TICI2b) was seen in 218 of 253 (86%) anterior circulation patients where this information was recorded. Early neurological recovery was seen in 109 of 231 (47%) patients. Day 90 mRS data was available for 176 (68%) patients, of whom 97 (55%) were functionally independent, 18 (10%) were severely dependent and 35 (20%) were dead. sICH occurred in 9 of 257 (4%) patients. The median length of stay in all healthcare facilities was eight days.
Posterior circulation occlusion patients
The 52 posterior circulation patients had a baseline median (range) NIHSS score of 20 (3–38), indicating severe disability. Twenty-two patients (42%) were treated with intravenous alteplase with a time from stroke onset to alteplase bolus of 148 minutes. Thirty-three (63%) patients were transferred to an ECR centre from a ‘home DHB’. The time from stroke onset to groin puncture was 266 minutes, and ECR was completed by 345 minutes. Fifty-one (98%) of posterior circulation patients had ECR under GA and 36 (70%) required ICU admission following the procedure. Complete or near-complete recanalisation was achieved in 42 of 47 (89%) patients. Early neurologic recovery was seen in 19 of 39 (49%) patients where this information is recorded. Day 90 mRS data was available for 47 patients, of whom 19 (40%) were functionally independent, eight (17%) were severely dependent and 14 (30%) were dead. sICH occurred in 2 of 50 (4%) patients. The median length of stay in all healthcare facilities was seven days.
Discussion
This study has found that stroke endovascular clot retrieval is being implemented in a safe and effective manner in New Zealand. Anterior circulation patients had a complete or near-complete recanalisation rate of 86%, and 55% of patients were functionally independent at three months. This compares with a large meta-analysis where 71% had complete or near complete recanalisation and 46% of patients were functionally independent.6 The onset to ECR completion time was also similar at 261 minutes in New Zealand compared to 285 minutes. The New Zealand mortality rates were higher at 20% versus 15% but our numbers are relatively small and patients had higher baseline NIHSS scores. The number of treated patients has grown exponentially from 30 in 2015 to 133 in 2017, with 250 patients projected for 2018.
Randomised-controlled trials of ECR in patients with occlusion of the basilar or posterior cerebral arteries are still underway. However, the use of ECR is considered reasonable for carefully selected patients,14 with a treatment window of up to 24 hours after symptom onset in Australian and New Zealand guidelines.15 In this study, basilar occlusion patients were severely disabled at baseline and had longer times to ECR completion than the anterior circulation patients. Basilar occlusion patients were also less likely to be functionally independent (40%), and had a higher mortality rate (30%) at three months. However, basilar occlusion patients receiving standard therapy alone have mortality rates as high as 80%.16
Endovascular clot retrieval is cost effective. A UK study reported upfront costs are high but quality-adjusted life expectancy is improved, and clot retrieval has a 100% probability of being cost effective at the minimum willingness to pay.17 The Australia/New Zealand EXTEND IA study, which provides important ‘local’ data, showed that the costs of consumables, staffing and inter-hospital transfer were offset by significantly shorter hospital stays.7 Clot retrieval patients spent a median of 73 (IQR 47–86) of the first 90 days at home, compared with only 15 (IQR 0–69) days in the standard care patients (p=0.006). There are also societal savings resulting from more people being independent and avoiding long-term care.
This study has a number of limitations. No resources are provided to maintain the database and we were dependent on the local centres recording all ECR patients and entering the data accurately. Outcome measures were not determined by an independent assessor. Follow-up data was missing in 10% of patients, reflecting the fact that many patients are transferred to home DHBs for ongoing care. This study highlights important achievements in the provision of ECR services in New Zealand. The numbers of ECR patients has grown, reflecting an expansion of services, with patients from 11 DHBs now treated, compared with only four prior to 2015. However, three quarters of the patients were treated at a single centre with major discrepancies in service provision across the country. Treatment figures per centre are due in part to differences in metropolitan population catchment areas, and there is still significant work required to fully implement regional treatment pathways in the Midland, Central and South Island regions. The DAWN and DEFUSE 3 studies have shown benefit in treating patients up to 24 hours, and 12 of the 312 patients were treated in this extended window.18,19 Patient selection beyond six hours requires advanced imaging that is currently available at only four large urban hospitals.
To meet these challenges, the Ministry of Health has established a National ECR Service Improvement Programme to help facilitate implementation efforts. Ongoing regional, inter-regional and inter-sector collaboration will be essential to implement comprehensive and equitable ECR services across all of New Zealand.
Summary
Abstract
Aim
Stroke endovascular clot retrieval (ECR) in patients with large proximal vessel occlusion improves clinical outcomes. We present the New Zealand ECR experience.
Method
All New Zealand patients treated with ECR since 2011 were included. Patients were considered eligible if they were independent prior to stroke and had proximal intracranial arterial occlusion.
Results
Three hundred and twelve patients [136 women, mean (SD) age of 64 (17) years] from 11 district health boards have been treated between March 2011 and April 2018. There were 260 (83%) patients with anterior and 52 (17%) with posterior circulation arterial occlusion. One hundred and ninety-three (62%) patients were pre-treated with intravenous alteplase. The median time from symptom onset to groin puncture was 210 (range 65-985) minutes. Complete or near-complete recanalisation (Thrombolysis in Cerebral Infarction scores of 3 or 2b) was achieved in 260 of 300 (87%) and the National Institutes of Health Stroke Scale score improved from a median of 18 at baseline to 7 at 24 hours. By day 90, 55% of the anterior circulation patients and 40% of the posterior circulation patients were living independently at home. Mortality rates were 20% for anterior circulation patients and 30% for the posterior circulation patients.
Conclusion
This study has shown that stroke endovascular clot retrieval is being provided safely and effectively in New Zealand. However, there remain discrepancies in service provision, and ongoing regional, inter-regional and inter-sector collaboration is essential to implement comprehensive and equitable ECR services across the country.
Author Information
Acknowledgements
Correspondence
Correspondence Email
Competing Interests
- Berkhemer OA, Fransen PS, Beumer D, et al. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med 2015; 372:11–20.
- Campbell BC, Mitchell PJ, Kleinig TJ, et al. Endovascular therapy for ischemic stroke with perfusion-imaging selection. N Engl J Med 2015; 372:1009–18.
- Goyal M, Demchuk AM, Menon BK, et al. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med 2015; 372:1019–30.
- Saver JL, Goyal M, Bonafe A, et al. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med 2015; 372:2285–95.
- Jovin TG, Chamorro A, Cobo E, et al. Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med 2015; 372:2296–306.
- Goyal M, Menon BK, van Zwam WH, et al. Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis of individual patient data from five randomised trials. Lancet 2016; 387:1723–31.
- Campbell BCV, Mitchell PJ, Churilov L, et al. Endovascular Thrombectomy for Ischemic Stroke Increases Disability-Free Survival, Quality of Life, and Life Expectancy and Reduces Cost. Front Neurol 2017; 8:657.
- Aronsson M, Persson J, Blomstrand C, Wester P, Levin LA. Cost-effectiveness of endovascular thrombectomy in patients with acute ischemic stroke. Neurology 2016; 86:1053–9.
- Barber PA, Liu Q, Brew S, et al. Endovascular clot retrieval for acute ischaemic stroke: the Auckland City Hospital experience. NZ Med J 2015; 128:57–62.
- Campbell BCV, Mitchell PJ, Churilov L, et al. Tenecteplase versus Alteplase before Thrombectomy for Ischemic Stroke. N Engl J Med 2018; 378:1573–82.
- Liu Q, Ranta AA, Abernethy G, Barber PA. Trends in New Zealand stroke thrombolysis treatment rates. NZ Med J 2017; 130:50–6.
- Higashida RT, Furlan AJ, Roberts H, et al. Trial design and reporting standards for intra-arterial cerebral thrombolysis for acute ischemic stroke. Stroke 2003; 34:e109–37.
- Wahlgren N, Ahmed N, Davalos A, et al. Thrombolysis with alteplase for acute ischaemic stroke in the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST): an observational study. Lancet 2007; 369:275–82.
- Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke 2018; 49:e46–e110.
- Australian Stroke Foundation. Clinical Guidelines for Stroke Management 2017. Melbourne, Australia 2017.
- Schonewille WJ, Wijman CA, Michel P, et al. Treatment and outcomes of acute basilar artery occlusion in the Basilar Artery International Cooperation Study (BASICS): a prospective registry study. Lancet Neurol 2009; 8:724–30.
- Ganesalingam J, Pizzo E, Morris S, Sunderland T, Ames D, Lobotesis K. Cost-Utility Analysis of Mechanical Thrombectomy Using Stent Retrievers in Acute Ischemic Stroke. Stroke 2015; 46:2591–8.
- Jovin TG, Nogueira RG, Investigators D. Thrombectomy 6 to 24 Hours after Stroke. N Engl J Med 2018; 378:1161–2.
- Albers GW, Marks MP, Kemp S, et al. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med 2018; 378:708–18.
For the PDF of this article,
contact nzmj@nzma.org.nz
View Article PDF
Stroke endovascular clot retrieval (ECR) for patients with large proximal intracranial artery occlusion has been shown to improve clinical outcomes.1–5 An individual patient level meta-analysis of five large randomised-controlled trials showed that for every 2.6 patients treated with ECR, one had a reduction in the modified Rankin Scale (mRS) score of least one point, compared with standard therapy.6 For every five patients treated with ECR, one more is functionally independent (mRS 0–2). ECR increases quality of life and is highly cost effective.7,8
ECR is time critical, technically challenging and needs to be available 24 hours per day to avoid treatment gaps. Auckland City, Wellington Regional and Christchurch hospitals are the only ones in New Zealand with the resources to provide this therapy at present, and only Auckland provides a 24-hour service. A regional treatment pathway has been developed in the Northern and Midland regions with patients transferred to Auckland for this therapy. Similar pathways centred on Wellington and Christchurch are being developed. The aim of this study was to determine if ECR is being delivered in a safe and effective manner.
Methods
Stroke ECR has been performed in New Zealand since 2011,9 with early patients treated as part of the Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial (EXTEND-IA) trial,2 and more recent patients enrolled in the follow-on EXTEND-IA Tenectoplase (EXTEND-IA TNK) and EXTEND-IA TNK2 studies.10 All ECR patients are entered into the New Zealand Thrombolysis Register, which is under the auspices of the National Stroke Network.11 Patients had to be previously independent and have large proximal intracranial arterial occlusion. Patients were treated with 0.9mg/kg alteplase or 0.25mg/kg tenecteplase for those patients enrolled in the EXTEND-IA TNK trial, if indicated.
Anterior circulation strokes are those with distal internal carotid artery (ICA) or M1/proximal M2 segment of the middle cerebral artery (MCA) occlusion. Posterior circulation strokes are those with occlusion of the basilar (BA), intracranial vertebral (VA) or posterior cerebral (PCA) arteries. Most anterior circulation patients were treated within six hours, and posterior circulation patients treated within 24 hours, of symptom onset. The neuro-interventionists used either a Solitaire FR (Covidien) or Trevo (Stryker) stent retriever and/or aspiration thrombectomy. A minority of patients required angioplasty and stenting of the ICA or MCA M1 during the procedure. The neuro-interventionist and anaesthetist decided on the use of a general anaesthetic or conscious sedation in each case. Recanalisation was determined using the Thrombolysis in Cerebral Infarction (TICI) scores where TICI3 is complete recanalisation and TICI2b is restoration of flow to greater than 50% of the affected territory.12
The National Institutes of Health Stroke Scale (NIHSS) was used to assess baseline and 24-hour stroke severity. The NIHSS ranges from 0 (normal) to 42 (dead). Early neurologic recovery was defined as either a decrease in NIHSS of ≥8 or a score of 0–1, at 24 hours. The mRS at day 90 was used to determine functional outcomes with 0 normal, 0–2 defined as functionally independent, 4–5 as significantly dependent, and 6 as dead. All adverse outcomes were recorded, with particular focus on symptomatic intracranial haemorrhage (sICH) and death. sICH was defined as parenchymal haemorrhage occupying >30% of the infarct volume and with significant mass effect on CT, and a reduction in NIHSS at 24 hours by ≥4.13
Results
Three hundred and twelve patients [136 women, mean (range) age of 64 (16–92) years] with ischaemic stroke from 11 DHBs have been treated with ECR in New Zealand between 2011 and the end of April 2018 (Table 1). Two hundred and forty-one patients were treated at Auckland City hospital, 57 at Christchurch hospital and 14 at Wellington hospital. There were 260 (83%) with anterior and 52 (17%) with posterior circulation occlusion. Thirty (10%) patients had a stroke while already in hospital and 157 (50%) were transferred to an ECR centre from another hospital. One hundred and seventy-six (56%) were admitted out-of-hours (Monday to Friday 17:00 to 08:00, and all day in weekends and holidays). One hundred and ninety-four (62%) were treated with IV alteplase prior to ECR. Day 90 mRS data was available for 227 of 252 (90%) patients treated before 31 January 2018.
Table 1: Results.
*New Zealand Ministry of Health Level 1 Ethnic Groups, and includes South Asians.
†Internal carotid artery (ICA), includes one bilateral occlusion, denominator 261.
‡First division of middle cerebral artery (M1).
§Second division of middle cerebral artery (M2).
‖Includes one vertebral artery occlusion and one posterior cerebral artery occlusion.
¶Endovascular clot retrieval (ECR).
**Thrombolysis in Cerebral Infarction (TICI).
††National Institute of Health Stroke Scale (NIHSS).
‡‡Modified Rankin Scale (mRS).
Anterior circulation occlusion patients
The 260 anterior circulation patients had baseline median (range) NIHSS scores of 18 (3–40), indicating severe disability. One hundred and seventy-two patients (66%) were treated with intravenous alteplase with a time from stroke onset to alteplase bolus of 123 minutes. One hundred and twenty-four (48%) patients were transferred to an ECR centre from a ‘home DHB’. The time from stroke onset to groin puncture was 200 minutes and ECR was completed by 261 minutes. Two hundred and twelve of 247 (86%) anterior circulation patients had ECR under GA and 29 of 257 (11%) required ICU admission following the procedure.
Complete or near complete recanalisation (TICI3 and TICI2b) was seen in 218 of 253 (86%) anterior circulation patients where this information was recorded. Early neurological recovery was seen in 109 of 231 (47%) patients. Day 90 mRS data was available for 176 (68%) patients, of whom 97 (55%) were functionally independent, 18 (10%) were severely dependent and 35 (20%) were dead. sICH occurred in 9 of 257 (4%) patients. The median length of stay in all healthcare facilities was eight days.
Posterior circulation occlusion patients
The 52 posterior circulation patients had a baseline median (range) NIHSS score of 20 (3–38), indicating severe disability. Twenty-two patients (42%) were treated with intravenous alteplase with a time from stroke onset to alteplase bolus of 148 minutes. Thirty-three (63%) patients were transferred to an ECR centre from a ‘home DHB’. The time from stroke onset to groin puncture was 266 minutes, and ECR was completed by 345 minutes. Fifty-one (98%) of posterior circulation patients had ECR under GA and 36 (70%) required ICU admission following the procedure. Complete or near-complete recanalisation was achieved in 42 of 47 (89%) patients. Early neurologic recovery was seen in 19 of 39 (49%) patients where this information is recorded. Day 90 mRS data was available for 47 patients, of whom 19 (40%) were functionally independent, eight (17%) were severely dependent and 14 (30%) were dead. sICH occurred in 2 of 50 (4%) patients. The median length of stay in all healthcare facilities was seven days.
Discussion
This study has found that stroke endovascular clot retrieval is being implemented in a safe and effective manner in New Zealand. Anterior circulation patients had a complete or near-complete recanalisation rate of 86%, and 55% of patients were functionally independent at three months. This compares with a large meta-analysis where 71% had complete or near complete recanalisation and 46% of patients were functionally independent.6 The onset to ECR completion time was also similar at 261 minutes in New Zealand compared to 285 minutes. The New Zealand mortality rates were higher at 20% versus 15% but our numbers are relatively small and patients had higher baseline NIHSS scores. The number of treated patients has grown exponentially from 30 in 2015 to 133 in 2017, with 250 patients projected for 2018.
Randomised-controlled trials of ECR in patients with occlusion of the basilar or posterior cerebral arteries are still underway. However, the use of ECR is considered reasonable for carefully selected patients,14 with a treatment window of up to 24 hours after symptom onset in Australian and New Zealand guidelines.15 In this study, basilar occlusion patients were severely disabled at baseline and had longer times to ECR completion than the anterior circulation patients. Basilar occlusion patients were also less likely to be functionally independent (40%), and had a higher mortality rate (30%) at three months. However, basilar occlusion patients receiving standard therapy alone have mortality rates as high as 80%.16
Endovascular clot retrieval is cost effective. A UK study reported upfront costs are high but quality-adjusted life expectancy is improved, and clot retrieval has a 100% probability of being cost effective at the minimum willingness to pay.17 The Australia/New Zealand EXTEND IA study, which provides important ‘local’ data, showed that the costs of consumables, staffing and inter-hospital transfer were offset by significantly shorter hospital stays.7 Clot retrieval patients spent a median of 73 (IQR 47–86) of the first 90 days at home, compared with only 15 (IQR 0–69) days in the standard care patients (p=0.006). There are also societal savings resulting from more people being independent and avoiding long-term care.
This study has a number of limitations. No resources are provided to maintain the database and we were dependent on the local centres recording all ECR patients and entering the data accurately. Outcome measures were not determined by an independent assessor. Follow-up data was missing in 10% of patients, reflecting the fact that many patients are transferred to home DHBs for ongoing care. This study highlights important achievements in the provision of ECR services in New Zealand. The numbers of ECR patients has grown, reflecting an expansion of services, with patients from 11 DHBs now treated, compared with only four prior to 2015. However, three quarters of the patients were treated at a single centre with major discrepancies in service provision across the country. Treatment figures per centre are due in part to differences in metropolitan population catchment areas, and there is still significant work required to fully implement regional treatment pathways in the Midland, Central and South Island regions. The DAWN and DEFUSE 3 studies have shown benefit in treating patients up to 24 hours, and 12 of the 312 patients were treated in this extended window.18,19 Patient selection beyond six hours requires advanced imaging that is currently available at only four large urban hospitals.
To meet these challenges, the Ministry of Health has established a National ECR Service Improvement Programme to help facilitate implementation efforts. Ongoing regional, inter-regional and inter-sector collaboration will be essential to implement comprehensive and equitable ECR services across all of New Zealand.
Summary
Abstract
Aim
Stroke endovascular clot retrieval (ECR) in patients with large proximal vessel occlusion improves clinical outcomes. We present the New Zealand ECR experience.
Method
All New Zealand patients treated with ECR since 2011 were included. Patients were considered eligible if they were independent prior to stroke and had proximal intracranial arterial occlusion.
Results
Three hundred and twelve patients [136 women, mean (SD) age of 64 (17) years] from 11 district health boards have been treated between March 2011 and April 2018. There were 260 (83%) patients with anterior and 52 (17%) with posterior circulation arterial occlusion. One hundred and ninety-three (62%) patients were pre-treated with intravenous alteplase. The median time from symptom onset to groin puncture was 210 (range 65-985) minutes. Complete or near-complete recanalisation (Thrombolysis in Cerebral Infarction scores of 3 or 2b) was achieved in 260 of 300 (87%) and the National Institutes of Health Stroke Scale score improved from a median of 18 at baseline to 7 at 24 hours. By day 90, 55% of the anterior circulation patients and 40% of the posterior circulation patients were living independently at home. Mortality rates were 20% for anterior circulation patients and 30% for the posterior circulation patients.
Conclusion
This study has shown that stroke endovascular clot retrieval is being provided safely and effectively in New Zealand. However, there remain discrepancies in service provision, and ongoing regional, inter-regional and inter-sector collaboration is essential to implement comprehensive and equitable ECR services across the country.
Author Information
Acknowledgements
Correspondence
Correspondence Email
Competing Interests
- Berkhemer OA, Fransen PS, Beumer D, et al. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med 2015; 372:11–20.
- Campbell BC, Mitchell PJ, Kleinig TJ, et al. Endovascular therapy for ischemic stroke with perfusion-imaging selection. N Engl J Med 2015; 372:1009–18.
- Goyal M, Demchuk AM, Menon BK, et al. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med 2015; 372:1019–30.
- Saver JL, Goyal M, Bonafe A, et al. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med 2015; 372:2285–95.
- Jovin TG, Chamorro A, Cobo E, et al. Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med 2015; 372:2296–306.
- Goyal M, Menon BK, van Zwam WH, et al. Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis of individual patient data from five randomised trials. Lancet 2016; 387:1723–31.
- Campbell BCV, Mitchell PJ, Churilov L, et al. Endovascular Thrombectomy for Ischemic Stroke Increases Disability-Free Survival, Quality of Life, and Life Expectancy and Reduces Cost. Front Neurol 2017; 8:657.
- Aronsson M, Persson J, Blomstrand C, Wester P, Levin LA. Cost-effectiveness of endovascular thrombectomy in patients with acute ischemic stroke. Neurology 2016; 86:1053–9.
- Barber PA, Liu Q, Brew S, et al. Endovascular clot retrieval for acute ischaemic stroke: the Auckland City Hospital experience. NZ Med J 2015; 128:57–62.
- Campbell BCV, Mitchell PJ, Churilov L, et al. Tenecteplase versus Alteplase before Thrombectomy for Ischemic Stroke. N Engl J Med 2018; 378:1573–82.
- Liu Q, Ranta AA, Abernethy G, Barber PA. Trends in New Zealand stroke thrombolysis treatment rates. NZ Med J 2017; 130:50–6.
- Higashida RT, Furlan AJ, Roberts H, et al. Trial design and reporting standards for intra-arterial cerebral thrombolysis for acute ischemic stroke. Stroke 2003; 34:e109–37.
- Wahlgren N, Ahmed N, Davalos A, et al. Thrombolysis with alteplase for acute ischaemic stroke in the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST): an observational study. Lancet 2007; 369:275–82.
- Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke 2018; 49:e46–e110.
- Australian Stroke Foundation. Clinical Guidelines for Stroke Management 2017. Melbourne, Australia 2017.
- Schonewille WJ, Wijman CA, Michel P, et al. Treatment and outcomes of acute basilar artery occlusion in the Basilar Artery International Cooperation Study (BASICS): a prospective registry study. Lancet Neurol 2009; 8:724–30.
- Ganesalingam J, Pizzo E, Morris S, Sunderland T, Ames D, Lobotesis K. Cost-Utility Analysis of Mechanical Thrombectomy Using Stent Retrievers in Acute Ischemic Stroke. Stroke 2015; 46:2591–8.
- Jovin TG, Nogueira RG, Investigators D. Thrombectomy 6 to 24 Hours after Stroke. N Engl J Med 2018; 378:1161–2.
- Albers GW, Marks MP, Kemp S, et al. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med 2018; 378:708–18.
Contact diana@nzma.org.nz
for the PDF of this article
View Article PDF
Stroke endovascular clot retrieval (ECR) for patients with large proximal intracranial artery occlusion has been shown to improve clinical outcomes.1–5 An individual patient level meta-analysis of five large randomised-controlled trials showed that for every 2.6 patients treated with ECR, one had a reduction in the modified Rankin Scale (mRS) score of least one point, compared with standard therapy.6 For every five patients treated with ECR, one more is functionally independent (mRS 0–2). ECR increases quality of life and is highly cost effective.7,8
ECR is time critical, technically challenging and needs to be available 24 hours per day to avoid treatment gaps. Auckland City, Wellington Regional and Christchurch hospitals are the only ones in New Zealand with the resources to provide this therapy at present, and only Auckland provides a 24-hour service. A regional treatment pathway has been developed in the Northern and Midland regions with patients transferred to Auckland for this therapy. Similar pathways centred on Wellington and Christchurch are being developed. The aim of this study was to determine if ECR is being delivered in a safe and effective manner.
Methods
Stroke ECR has been performed in New Zealand since 2011,9 with early patients treated as part of the Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial (EXTEND-IA) trial,2 and more recent patients enrolled in the follow-on EXTEND-IA Tenectoplase (EXTEND-IA TNK) and EXTEND-IA TNK2 studies.10 All ECR patients are entered into the New Zealand Thrombolysis Register, which is under the auspices of the National Stroke Network.11 Patients had to be previously independent and have large proximal intracranial arterial occlusion. Patients were treated with 0.9mg/kg alteplase or 0.25mg/kg tenecteplase for those patients enrolled in the EXTEND-IA TNK trial, if indicated.
Anterior circulation strokes are those with distal internal carotid artery (ICA) or M1/proximal M2 segment of the middle cerebral artery (MCA) occlusion. Posterior circulation strokes are those with occlusion of the basilar (BA), intracranial vertebral (VA) or posterior cerebral (PCA) arteries. Most anterior circulation patients were treated within six hours, and posterior circulation patients treated within 24 hours, of symptom onset. The neuro-interventionists used either a Solitaire FR (Covidien) or Trevo (Stryker) stent retriever and/or aspiration thrombectomy. A minority of patients required angioplasty and stenting of the ICA or MCA M1 during the procedure. The neuro-interventionist and anaesthetist decided on the use of a general anaesthetic or conscious sedation in each case. Recanalisation was determined using the Thrombolysis in Cerebral Infarction (TICI) scores where TICI3 is complete recanalisation and TICI2b is restoration of flow to greater than 50% of the affected territory.12
The National Institutes of Health Stroke Scale (NIHSS) was used to assess baseline and 24-hour stroke severity. The NIHSS ranges from 0 (normal) to 42 (dead). Early neurologic recovery was defined as either a decrease in NIHSS of ≥8 or a score of 0–1, at 24 hours. The mRS at day 90 was used to determine functional outcomes with 0 normal, 0–2 defined as functionally independent, 4–5 as significantly dependent, and 6 as dead. All adverse outcomes were recorded, with particular focus on symptomatic intracranial haemorrhage (sICH) and death. sICH was defined as parenchymal haemorrhage occupying >30% of the infarct volume and with significant mass effect on CT, and a reduction in NIHSS at 24 hours by ≥4.13
Results
Three hundred and twelve patients [136 women, mean (range) age of 64 (16–92) years] with ischaemic stroke from 11 DHBs have been treated with ECR in New Zealand between 2011 and the end of April 2018 (Table 1). Two hundred and forty-one patients were treated at Auckland City hospital, 57 at Christchurch hospital and 14 at Wellington hospital. There were 260 (83%) with anterior and 52 (17%) with posterior circulation occlusion. Thirty (10%) patients had a stroke while already in hospital and 157 (50%) were transferred to an ECR centre from another hospital. One hundred and seventy-six (56%) were admitted out-of-hours (Monday to Friday 17:00 to 08:00, and all day in weekends and holidays). One hundred and ninety-four (62%) were treated with IV alteplase prior to ECR. Day 90 mRS data was available for 227 of 252 (90%) patients treated before 31 January 2018.
Table 1: Results.
*New Zealand Ministry of Health Level 1 Ethnic Groups, and includes South Asians.
†Internal carotid artery (ICA), includes one bilateral occlusion, denominator 261.
‡First division of middle cerebral artery (M1).
§Second division of middle cerebral artery (M2).
‖Includes one vertebral artery occlusion and one posterior cerebral artery occlusion.
¶Endovascular clot retrieval (ECR).
**Thrombolysis in Cerebral Infarction (TICI).
††National Institute of Health Stroke Scale (NIHSS).
‡‡Modified Rankin Scale (mRS).
Anterior circulation occlusion patients
The 260 anterior circulation patients had baseline median (range) NIHSS scores of 18 (3–40), indicating severe disability. One hundred and seventy-two patients (66%) were treated with intravenous alteplase with a time from stroke onset to alteplase bolus of 123 minutes. One hundred and twenty-four (48%) patients were transferred to an ECR centre from a ‘home DHB’. The time from stroke onset to groin puncture was 200 minutes and ECR was completed by 261 minutes. Two hundred and twelve of 247 (86%) anterior circulation patients had ECR under GA and 29 of 257 (11%) required ICU admission following the procedure.
Complete or near complete recanalisation (TICI3 and TICI2b) was seen in 218 of 253 (86%) anterior circulation patients where this information was recorded. Early neurological recovery was seen in 109 of 231 (47%) patients. Day 90 mRS data was available for 176 (68%) patients, of whom 97 (55%) were functionally independent, 18 (10%) were severely dependent and 35 (20%) were dead. sICH occurred in 9 of 257 (4%) patients. The median length of stay in all healthcare facilities was eight days.
Posterior circulation occlusion patients
The 52 posterior circulation patients had a baseline median (range) NIHSS score of 20 (3–38), indicating severe disability. Twenty-two patients (42%) were treated with intravenous alteplase with a time from stroke onset to alteplase bolus of 148 minutes. Thirty-three (63%) patients were transferred to an ECR centre from a ‘home DHB’. The time from stroke onset to groin puncture was 266 minutes, and ECR was completed by 345 minutes. Fifty-one (98%) of posterior circulation patients had ECR under GA and 36 (70%) required ICU admission following the procedure. Complete or near-complete recanalisation was achieved in 42 of 47 (89%) patients. Early neurologic recovery was seen in 19 of 39 (49%) patients where this information is recorded. Day 90 mRS data was available for 47 patients, of whom 19 (40%) were functionally independent, eight (17%) were severely dependent and 14 (30%) were dead. sICH occurred in 2 of 50 (4%) patients. The median length of stay in all healthcare facilities was seven days.
Discussion
This study has found that stroke endovascular clot retrieval is being implemented in a safe and effective manner in New Zealand. Anterior circulation patients had a complete or near-complete recanalisation rate of 86%, and 55% of patients were functionally independent at three months. This compares with a large meta-analysis where 71% had complete or near complete recanalisation and 46% of patients were functionally independent.6 The onset to ECR completion time was also similar at 261 minutes in New Zealand compared to 285 minutes. The New Zealand mortality rates were higher at 20% versus 15% but our numbers are relatively small and patients had higher baseline NIHSS scores. The number of treated patients has grown exponentially from 30 in 2015 to 133 in 2017, with 250 patients projected for 2018.
Randomised-controlled trials of ECR in patients with occlusion of the basilar or posterior cerebral arteries are still underway. However, the use of ECR is considered reasonable for carefully selected patients,14 with a treatment window of up to 24 hours after symptom onset in Australian and New Zealand guidelines.15 In this study, basilar occlusion patients were severely disabled at baseline and had longer times to ECR completion than the anterior circulation patients. Basilar occlusion patients were also less likely to be functionally independent (40%), and had a higher mortality rate (30%) at three months. However, basilar occlusion patients receiving standard therapy alone have mortality rates as high as 80%.16
Endovascular clot retrieval is cost effective. A UK study reported upfront costs are high but quality-adjusted life expectancy is improved, and clot retrieval has a 100% probability of being cost effective at the minimum willingness to pay.17 The Australia/New Zealand EXTEND IA study, which provides important ‘local’ data, showed that the costs of consumables, staffing and inter-hospital transfer were offset by significantly shorter hospital stays.7 Clot retrieval patients spent a median of 73 (IQR 47–86) of the first 90 days at home, compared with only 15 (IQR 0–69) days in the standard care patients (p=0.006). There are also societal savings resulting from more people being independent and avoiding long-term care.
This study has a number of limitations. No resources are provided to maintain the database and we were dependent on the local centres recording all ECR patients and entering the data accurately. Outcome measures were not determined by an independent assessor. Follow-up data was missing in 10% of patients, reflecting the fact that many patients are transferred to home DHBs for ongoing care. This study highlights important achievements in the provision of ECR services in New Zealand. The numbers of ECR patients has grown, reflecting an expansion of services, with patients from 11 DHBs now treated, compared with only four prior to 2015. However, three quarters of the patients were treated at a single centre with major discrepancies in service provision across the country. Treatment figures per centre are due in part to differences in metropolitan population catchment areas, and there is still significant work required to fully implement regional treatment pathways in the Midland, Central and South Island regions. The DAWN and DEFUSE 3 studies have shown benefit in treating patients up to 24 hours, and 12 of the 312 patients were treated in this extended window.18,19 Patient selection beyond six hours requires advanced imaging that is currently available at only four large urban hospitals.
To meet these challenges, the Ministry of Health has established a National ECR Service Improvement Programme to help facilitate implementation efforts. Ongoing regional, inter-regional and inter-sector collaboration will be essential to implement comprehensive and equitable ECR services across all of New Zealand.
Summary
Abstract
Aim
Stroke endovascular clot retrieval (ECR) in patients with large proximal vessel occlusion improves clinical outcomes. We present the New Zealand ECR experience.
Method
All New Zealand patients treated with ECR since 2011 were included. Patients were considered eligible if they were independent prior to stroke and had proximal intracranial arterial occlusion.
Results
Three hundred and twelve patients [136 women, mean (SD) age of 64 (17) years] from 11 district health boards have been treated between March 2011 and April 2018. There were 260 (83%) patients with anterior and 52 (17%) with posterior circulation arterial occlusion. One hundred and ninety-three (62%) patients were pre-treated with intravenous alteplase. The median time from symptom onset to groin puncture was 210 (range 65-985) minutes. Complete or near-complete recanalisation (Thrombolysis in Cerebral Infarction scores of 3 or 2b) was achieved in 260 of 300 (87%) and the National Institutes of Health Stroke Scale score improved from a median of 18 at baseline to 7 at 24 hours. By day 90, 55% of the anterior circulation patients and 40% of the posterior circulation patients were living independently at home. Mortality rates were 20% for anterior circulation patients and 30% for the posterior circulation patients.
Conclusion
This study has shown that stroke endovascular clot retrieval is being provided safely and effectively in New Zealand. However, there remain discrepancies in service provision, and ongoing regional, inter-regional and inter-sector collaboration is essential to implement comprehensive and equitable ECR services across the country.
Author Information
Acknowledgements
Correspondence
Correspondence Email
Competing Interests
- Berkhemer OA, Fransen PS, Beumer D, et al. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med 2015; 372:11–20.
- Campbell BC, Mitchell PJ, Kleinig TJ, et al. Endovascular therapy for ischemic stroke with perfusion-imaging selection. N Engl J Med 2015; 372:1009–18.
- Goyal M, Demchuk AM, Menon BK, et al. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med 2015; 372:1019–30.
- Saver JL, Goyal M, Bonafe A, et al. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med 2015; 372:2285–95.
- Jovin TG, Chamorro A, Cobo E, et al. Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med 2015; 372:2296–306.
- Goyal M, Menon BK, van Zwam WH, et al. Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis of individual patient data from five randomised trials. Lancet 2016; 387:1723–31.
- Campbell BCV, Mitchell PJ, Churilov L, et al. Endovascular Thrombectomy for Ischemic Stroke Increases Disability-Free Survival, Quality of Life, and Life Expectancy and Reduces Cost. Front Neurol 2017; 8:657.
- Aronsson M, Persson J, Blomstrand C, Wester P, Levin LA. Cost-effectiveness of endovascular thrombectomy in patients with acute ischemic stroke. Neurology 2016; 86:1053–9.
- Barber PA, Liu Q, Brew S, et al. Endovascular clot retrieval for acute ischaemic stroke: the Auckland City Hospital experience. NZ Med J 2015; 128:57–62.
- Campbell BCV, Mitchell PJ, Churilov L, et al. Tenecteplase versus Alteplase before Thrombectomy for Ischemic Stroke. N Engl J Med 2018; 378:1573–82.
- Liu Q, Ranta AA, Abernethy G, Barber PA. Trends in New Zealand stroke thrombolysis treatment rates. NZ Med J 2017; 130:50–6.
- Higashida RT, Furlan AJ, Roberts H, et al. Trial design and reporting standards for intra-arterial cerebral thrombolysis for acute ischemic stroke. Stroke 2003; 34:e109–37.
- Wahlgren N, Ahmed N, Davalos A, et al. Thrombolysis with alteplase for acute ischaemic stroke in the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST): an observational study. Lancet 2007; 369:275–82.
- Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke 2018; 49:e46–e110.
- Australian Stroke Foundation. Clinical Guidelines for Stroke Management 2017. Melbourne, Australia 2017.
- Schonewille WJ, Wijman CA, Michel P, et al. Treatment and outcomes of acute basilar artery occlusion in the Basilar Artery International Cooperation Study (BASICS): a prospective registry study. Lancet Neurol 2009; 8:724–30.
- Ganesalingam J, Pizzo E, Morris S, Sunderland T, Ames D, Lobotesis K. Cost-Utility Analysis of Mechanical Thrombectomy Using Stent Retrievers in Acute Ischemic Stroke. Stroke 2015; 46:2591–8.
- Jovin TG, Nogueira RG, Investigators D. Thrombectomy 6 to 24 Hours after Stroke. N Engl J Med 2018; 378:1161–2.
- Albers GW, Marks MP, Kemp S, et al. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med 2018; 378:708–18.
Contact diana@nzma.org.nz
for the PDF of this article
Endovascular clot retrieval for acute ischaemic stroke in New Zealand
Subscriber Content
The full contents of this pages only available to subscribers.
Login, subscribe or email nzmj@nzma.org.nz to purchase this article.
