In the treatment of patients presenting with ST-elevation myocardial infarction (STEMI), the benefits of reperfusion therapy are well-recognised and time-dependent.1 Primary percutaneous coronary intervention (PPCI) has been widely demonstrated to be superior to fibrinolysis as a reperfusion strategy in STEMI when a door-to-balloon (DTB) time of less than 90 minutes is achieved.2-5Outside metropolitan settings in New Zealand, access to onsite primary angioplasty services does not exist so fibrinolysis has remained the only reperfusion strategy available to many patients presenting with STEMI. In more populous settings internationally, highly sophisticated regional systems employing urgent road transfer of STEMI patients to nearby angioplasty-capable facilities have been shown to be superior to onsite fibrinolysis.6-9 Where greater distance precludes road transfer, this has been extended to successful helicopter transfer of small numbers of patients for PPCI with improving transfer times and a trend towards reduced mortality.10-13Some evidence has suggested that excellent outcomes can be achieved with transfer for PPCI beyond traditional deadlines.14 With the increasing utilisation of a transfer strategy in PPCI and this supportive evidence, some guidelines allow a delay of up to 120 minutes from first medical contact to balloon time.4 Nonetheless, concern remains that the potential benefits of early reperfusion may be lost due to unacceptable transfer delays in this setting.15A rapid helicopter transfer pathway for PPCI was established between a neighbouring urban hospital and our PCI-capable facility in May 2010. We aimed to determine the feasibility of rapid helicopter transfer of STEMI patients for PPCI in our local context. The clinical characteristics, times to reperfusion and clinical outcomes of these patients are reported.Method A protocol for the rapid helicopter transfer of STEMI patients from Whangarei Hospital to Auckland City Hospital was developed and introduced in May 2010. Prior to this, no documented protocol existed for PPCI in STEMI patients presenting to Whangarei Hospital, so primary angioplasty was not routinely considered as a reperfusion strategy. The referring hospital is a 223-bed, urban, secondary-level hospital. It services an urban population of approximately 48,000 patients and a large rural catchment area extending over 12,500km2, including approximately a further 106,000 patients. The receiving hospital is a 1000-bed, urban, quaternary-level hospital with 24-hour PPCI capability. It serves a metropolitan population of 439,000 but is the only hospital in a city of 1.4 million people to provide a 24-hour PPCI service. It performs approximately 950 PCI procedures per year. Helicopter transfer between the referring and receiving institutions requires a 132km flight, with duration of approximately 35 minutes. The only alternative transfer option between the 2 hospitals is a 165km road transfer by ambulance. Helicopter transfer was provided by a regional medical transfer service with 2 aircraft, both of which are Sikorsky S-76A helicopters. This service is based 3km from the referring hospital and was staffed and available by telephone contact 24 hours daily. The service provided by the carrier was not exclusive to this PPCI pathway or the referring hospital, providing all general helicopter medical transfer services in the region. Flights were staffed by 2 pilots and one advanced paramedic. The clinical records of all patients undergoing helicopter transfer for PPCI between May 2010 and August 2011 were retrospectively reviewed. The records of all patients undergoing urgent transfer for coronary revascularisation were screened for inclusion. Where doubt existed as to the appropriateness of a patient's inclusion, this was adjudicated on by a senior author. The key determinant of inclusion was that the referring doctor's clinical impression was of STEMI. Patients who received fibrinolytic therapy at the referring institution and were subsequently transferred for rescue PCI were excluded from the analysis. In order to provide some context to clinical practice at the referring hospital, limited clinical information was retrospectively reviewed for STEMI patients undergoing fibrinolysis during the same period. This clinical pathway was designed to test the feasibility of rapid transfer of a highly selected population and was not intended to define treatment arms for comparison between fibrinolysis and primary angioplasty. All patients presenting to the referring hospital with angina within 12 hours of symptom onset and with ST elevation of at least 1mm in 2 contiguous limb leads or 2mm in 2 contiguous precordial leads, a left bundle branch block or true posterior STEMI were considered eligible for the pathway. Patients with inferior STEMI presenting within 3 hours of symptom onset were directed towards a fibrinolytic strategy but transfer for PPCI was available at the discretion of the referring physician. Once STEMI was diagnosed and provided there were no pre-defined contraindications to transfer, the referring Emergency Physician was prompted to make urgent contact with the transferring helicopter service to rapidly determine the feasibility of transfer. Where the likelihood of significant delay in helicopter transfer existed, the referring clinician was directed to immediately administer fibrinolytic therapy (tenecteplase). The patient was then admitted to the referring hospital's inpatient facility with a view to early road transfer for coronary angiography within 48 hours. The option of immediate helicopter transfer for rescue PCI remained for those patients with persistent angina or <50% resolution of ST segment elevation 1 hour after the administration of fibrinolysis. Where rapid transfer was feasible, the on-call interventional cardiologist at the receiving hospital was immediately contacted by a direct mobile telephone number and advised of the pending arrival of a STEMI patient. The receiving cardiologist then activated the usual cardiac catheterisation laboratory (CCL) PPCI protocol. The receiving cardiologist did not routinely review the ECGs of transferred patients until their arrival at the CCL. The time of arrival at the referring hospital (door 1 time) was documented electronically by that hospital's emergency department and was made available for this analysis. All clinical notes from that hospital were reviewed including ECGs and medication records. The time of symptom onset was patient-reported as documented in the clinical record. In the case of patients who developed STEMI within the emergency department of the referring hospital (2 cases), the time of the first ECG documenting ST elevation was taken as the door time. Flight logbooks and telephone records of the helicopter service provider were available to provide flight times and the time at which first contact was made by the referring clinician. Electronic records of all events in the CCL were reviewed to determine the time of arrival and the time of thrombus aspiration or balloon inflation, whichever occurred first. This time was defined as the balloon time. Normal working hours were defined as between 8am and 5pm Monday to Friday, excluding public holidays. Nine time intervals of interest were defined and reported in each case: symptom onset to door 1 time, door 1 to ECG time, door 1 to helicopter contact time, helicopter contact time to departure time, door 1 to helicopter departure time, flight time, door 2 to arrival in the CCL, CCL arrival to balloon time and door 1 to balloon time. Patients were characterised by age, sex and high-risk features including anterior STEMI and the presence of cardiogenic shock (defined as systolic blood pressure <90mmHg unresponsive to fluid administration, requiring vasopressors). Details of percutaneous intervention undertaken were available from CCL electronic records and angiographic cines were reviewed to determine the angiographic success of the procedure. Coronary flow before and after percutaneous intervention was defined according to the classification of the Thrombolysis in Myocardial Infarction (TIMI) trial.16 Clinical outcome data was available from electronic records including the need for repeat intervention, cardiac surgery, 30-day major adverse cardiac events and mortality. The primary endpoint was the proportion of patients with a DTB time of less than 120 minutes. Secondary endpoints included 30-day mortality and 30-day re-infarction, defined as recurrent chest pain associated with ST segment change or recurrent elevation of cardiac enzymes. Results Between May 2010 and August 2011, 24 patients presenting to the referring hospital with STEMI underwent urgent helicopter transfer for PPCI. In the same period, a total of 45 patients presented to the referring hospital with STEMI. Of these, 21 received fibrinolysis as the primary reperfusion strategy within the emergency department. Only 1 of these patients was considered for the rapid transfer STEMI protocol but did not undergo transfer due to anticipated transfer delays. The reperfusion strategy was at the discretion of the admitting physician. As helicopter transfer for PPCI was an evolving strategy, it may not have been considered or thought feasible in a significant number of early cases. Three of the 21 patients receiving fibrinolysis subsequently required urgent transfer for rescue PCI. A further 13 patients received pre-hospital thrombolysis. Table 1 summarises the characteristics of the patients undergoing transfer. The majority of patients (15\/24, 63%) presented to the referring hospital by ambulance and ST elevation was demonstrated on a pre-hospital ECG in 10\/24 (42%) of patients. Most patients (20\/24, 83%) presented within 3 hours of symptom onset. Table 1. Baseline characteristics Characteristic (n=24) Value Age, median (IQR) (years) 63 (56-71) Male, n (%) 19 (79) NZ European, n (%) 19 (79) Medical history, n (%) Hypertension Diabetes Dyslipidemia Smoker Known CAD Previous angioplasty Previous CABG 9 (38) 5 (21) 7 (29) 6 (25) 0 0 0 Clinical features, n (%) Cardiogenic shock Anterior Lateral Inferior Posterior New LBBB 0 14 (58) 0 10 (42) 0 0 Presentation <3 hours of symptoms, n (%) 20 (83) Presentation, n (%) Working hours After hours 9 (38) 15 (62) Pre-hospital STEMI ECG, n (%) 10\/24 (42) CAD = coronary artery disease, CABG = coronary artery bypass graft surgery, LBBB = left bundle branch block. The overall median DTB time was 125 minutes (interquartile range 117-147 minutes). The distribution of these time intervals is demonstrated in figures 1a and 1b. For the 9 patients presenting within working hours, the median reperfusion time was 122 minutes (IQR 105-136 minutes), compared with 134 minutes (IQR 117-159 minutes) in the 15 patients presenting outside working hours. The greatest delay was from triage to departure from the referring hospital. This interval was a mean time of 59 minutes and contributed a mean delay of 44% of the total DTB time. The time course of each patient, from presentation at the referring hospital to PPCI, is summarised in Figure 2. The primary endpoint was achieved in 8\/24 cases (33%) of whom one achieved a DTB time of less than 90 minutes. A further 8\/24 (33%) cases were within 15 minutes of achieving a DTB time of 120 minutes. A DTB time of greater than 180 minutes was observed in 2\/24 patients (8%). Both patients presented outside normal working hours. Other time intervals are summarised in Table 2. Table 2. Time intervals in transfer Time interval, minutes (n=24) Value Referring hospital Symptom onset to door 1 97 (43-163) Door 1 to ECG 5 (2-7) ECG to contact helicopter 15 (9-19) Contact helicopter to departure 35 (24-46) Door 1 to departure 56 (47-63) Transport times Transfer flight time 33 (31-35) Door 1 to door 2 89 (77-98) PCI centre Door 2 to CCL 17 (15-21) CCL to balloon 19 (15-25) Door 2 to balloon 35 (31-42) Total door 1 to balloon 125 (117-147) Working hours 122 (105-136) After hours 134 (117-159) Door 1 to balloon time <90 minutes, n (%) 1 (4) Door 1 to balloon time <120 minutes, n (%) 8 (33) Values are median (interquartile range). CCL = cardiac catheterisation laboratory. No patients required resuscitation or defibrillation during helicopter transfer. The CCL was falsely activated in 2\/24 (8%) cases. In both cases, although the criteria for STEMI were not met, the patient was found to have significant obstructive disease and myocardial infarction (non-STEMI) and underwent PCI. One patient with STEMI did not undergo PCI, rather undergoing thrombus aspiration in the setting of severe 3-vessel coronary disease, before proceeding to elective inpatient coronary bypass surgery. Prior to intervention, 18\/24 (66%) patients had TIMI grade 0-1 flow. Following intervention, normal (TIMI 3) coronary flow was established in 22\/24 (92%) of the vessels undergoing intervention. The culprit artery was the left anterior descending artery in 14\/24 (58%) cases. In all cases of intervention, only the culprit vessel was treated acutely. However, 3\/23 (13%) patients undergoing PCI required staged PCI to a non-culprit lesion in another coronary artery at a later admission. Drug-eluting stents were used in 14\/23 (61%) of PCI cases. No patients required repeated percutaneous intervention during the STEMI admission although 2\/23 (8%) of the patients who underwent PCI required non-emergent coronary bypass surgery duri

In the treatment of patients presenting with ST-elevation myocardial infarction (STEMI), the benefits of reperfusion therapy are well-recognised and time-dependent.1 Primary percutaneous coronary intervention (PPCI) has been widely demonstrated to be superior to fibrinolysis as a reperfusion strategy in STEMI when a door-to-balloon (DTB) time of less than 90 minutes is achieved.2-5Outside metropolitan settings in New Zealand, access to onsite primary angioplasty services does not exist so fibrinolysis has remained the only reperfusion strategy available to many patients presenting with STEMI. In more populous settings internationally, highly sophisticated regional systems employing urgent road transfer of STEMI patients to nearby angioplasty-capable facilities have been shown to be superior to onsite fibrinolysis.6-9 Where greater distance precludes road transfer, this has been extended to successful helicopter transfer of small numbers of patients for PPCI with improving transfer times and a trend towards reduced mortality.10-13Some evidence has suggested that excellent outcomes can be achieved with transfer for PPCI beyond traditional deadlines.14 With the increasing utilisation of a transfer strategy in PPCI and this supportive evidence, some guidelines allow a delay of up to 120 minutes from first medical contact to balloon time.4 Nonetheless, concern remains that the potential benefits of early reperfusion may be lost due to unacceptable transfer delays in this setting.15A rapid helicopter transfer pathway for PPCI was established between a neighbouring urban hospital and our PCI-capable facility in May 2010. We aimed to determine the feasibility of rapid helicopter transfer of STEMI patients for PPCI in our local context. The clinical characteristics, times to reperfusion and clinical outcomes of these patients are reported.Method A protocol for the rapid helicopter transfer of STEMI patients from Whangarei Hospital to Auckland City Hospital was developed and introduced in May 2010. Prior to this, no documented protocol existed for PPCI in STEMI patients presenting to Whangarei Hospital, so primary angioplasty was not routinely considered as a reperfusion strategy. The referring hospital is a 223-bed, urban, secondary-level hospital. It services an urban population of approximately 48,000 patients and a large rural catchment area extending over 12,500km2, including approximately a further 106,000 patients. The receiving hospital is a 1000-bed, urban, quaternary-level hospital with 24-hour PPCI capability. It serves a metropolitan population of 439,000 but is the only hospital in a city of 1.4 million people to provide a 24-hour PPCI service. It performs approximately 950 PCI procedures per year. Helicopter transfer between the referring and receiving institutions requires a 132km flight, with duration of approximately 35 minutes. The only alternative transfer option between the 2 hospitals is a 165km road transfer by ambulance. Helicopter transfer was provided by a regional medical transfer service with 2 aircraft, both of which are Sikorsky S-76A helicopters. This service is based 3km from the referring hospital and was staffed and available by telephone contact 24 hours daily. The service provided by the carrier was not exclusive to this PPCI pathway or the referring hospital, providing all general helicopter medical transfer services in the region. Flights were staffed by 2 pilots and one advanced paramedic. The clinical records of all patients undergoing helicopter transfer for PPCI between May 2010 and August 2011 were retrospectively reviewed. The records of all patients undergoing urgent transfer for coronary revascularisation were screened for inclusion. Where doubt existed as to the appropriateness of a patient's inclusion, this was adjudicated on by a senior author. The key determinant of inclusion was that the referring doctor's clinical impression was of STEMI. Patients who received fibrinolytic therapy at the referring institution and were subsequently transferred for rescue PCI were excluded from the analysis. In order to provide some context to clinical practice at the referring hospital, limited clinical information was retrospectively reviewed for STEMI patients undergoing fibrinolysis during the same period. This clinical pathway was designed to test the feasibility of rapid transfer of a highly selected population and was not intended to define treatment arms for comparison between fibrinolysis and primary angioplasty. All patients presenting to the referring hospital with angina within 12 hours of symptom onset and with ST elevation of at least 1mm in 2 contiguous limb leads or 2mm in 2 contiguous precordial leads, a left bundle branch block or true posterior STEMI were considered eligible for the pathway. Patients with inferior STEMI presenting within 3 hours of symptom onset were directed towards a fibrinolytic strategy but transfer for PPCI was available at the discretion of the referring physician. Once STEMI was diagnosed and provided there were no pre-defined contraindications to transfer, the referring Emergency Physician was prompted to make urgent contact with the transferring helicopter service to rapidly determine the feasibility of transfer. Where the likelihood of significant delay in helicopter transfer existed, the referring clinician was directed to immediately administer fibrinolytic therapy (tenecteplase). The patient was then admitted to the referring hospital's inpatient facility with a view to early road transfer for coronary angiography within 48 hours. The option of immediate helicopter transfer for rescue PCI remained for those patients with persistent angina or <50% resolution of ST segment elevation 1 hour after the administration of fibrinolysis. Where rapid transfer was feasible, the on-call interventional cardiologist at the receiving hospital was immediately contacted by a direct mobile telephone number and advised of the pending arrival of a STEMI patient. The receiving cardiologist then activated the usual cardiac catheterisation laboratory (CCL) PPCI protocol. The receiving cardiologist did not routinely review the ECGs of transferred patients until their arrival at the CCL. The time of arrival at the referring hospital (door 1 time) was documented electronically by that hospital's emergency department and was made available for this analysis. All clinical notes from that hospital were reviewed including ECGs and medication records. The time of symptom onset was patient-reported as documented in the clinical record. In the case of patients who developed STEMI within the emergency department of the referring hospital (2 cases), the time of the first ECG documenting ST elevation was taken as the door time. Flight logbooks and telephone records of the helicopter service provider were available to provide flight times and the time at which first contact was made by the referring clinician. Electronic records of all events in the CCL were reviewed to determine the time of arrival and the time of thrombus aspiration or balloon inflation, whichever occurred first. This time was defined as the balloon time. Normal working hours were defined as between 8am and 5pm Monday to Friday, excluding public holidays. Nine time intervals of interest were defined and reported in each case: symptom onset to door 1 time, door 1 to ECG time, door 1 to helicopter contact time, helicopter contact time to departure time, door 1 to helicopter departure time, flight time, door 2 to arrival in the CCL, CCL arrival to balloon time and door 1 to balloon time. Patients were characterised by age, sex and high-risk features including anterior STEMI and the presence of cardiogenic shock (defined as systolic blood pressure <90mmHg unresponsive to fluid administration, requiring vasopressors). Details of percutaneous intervention undertaken were available from CCL electronic records and angiographic cines were reviewed to determine the angiographic success of the procedure. Coronary flow before and after percutaneous intervention was defined according to the classification of the Thrombolysis in Myocardial Infarction (TIMI) trial.16 Clinical outcome data was available from electronic records including the need for repeat intervention, cardiac surgery, 30-day major adverse cardiac events and mortality. The primary endpoint was the proportion of patients with a DTB time of less than 120 minutes. Secondary endpoints included 30-day mortality and 30-day re-infarction, defined as recurrent chest pain associated with ST segment change or recurrent elevation of cardiac enzymes. Results Between May 2010 and August 2011, 24 patients presenting to the referring hospital with STEMI underwent urgent helicopter transfer for PPCI. In the same period, a total of 45 patients presented to the referring hospital with STEMI. Of these, 21 received fibrinolysis as the primary reperfusion strategy within the emergency department. Only 1 of these patients was considered for the rapid transfer STEMI protocol but did not undergo transfer due to anticipated transfer delays. The reperfusion strategy was at the discretion of the admitting physician. As helicopter transfer for PPCI was an evolving strategy, it may not have been considered or thought feasible in a significant number of early cases. Three of the 21 patients receiving fibrinolysis subsequently required urgent transfer for rescue PCI. A further 13 patients received pre-hospital thrombolysis. Table 1 summarises the characteristics of the patients undergoing transfer. The majority of patients (15\/24, 63%) presented to the referring hospital by ambulance and ST elevation was demonstrated on a pre-hospital ECG in 10\/24 (42%) of patients. Most patients (20\/24, 83%) presented within 3 hours of symptom onset. Table 1. Baseline characteristics Characteristic (n=24) Value Age, median (IQR) (years) 63 (56-71) Male, n (%) 19 (79) NZ European, n (%) 19 (79) Medical history, n (%) Hypertension Diabetes Dyslipidemia Smoker Known CAD Previous angioplasty Previous CABG 9 (38) 5 (21) 7 (29) 6 (25) 0 0 0 Clinical features, n (%) Cardiogenic shock Anterior Lateral Inferior Posterior New LBBB 0 14 (58) 0 10 (42) 0 0 Presentation <3 hours of symptoms, n (%) 20 (83) Presentation, n (%) Working hours After hours 9 (38) 15 (62) Pre-hospital STEMI ECG, n (%) 10\/24 (42) CAD = coronary artery disease, CABG = coronary artery bypass graft surgery, LBBB = left bundle branch block. The overall median DTB time was 125 minutes (interquartile range 117-147 minutes). The distribution of these time intervals is demonstrated in figures 1a and 1b. For the 9 patients presenting within working hours, the median reperfusion time was 122 minutes (IQR 105-136 minutes), compared with 134 minutes (IQR 117-159 minutes) in the 15 patients presenting outside working hours. The greatest delay was from triage to departure from the referring hospital. This interval was a mean time of 59 minutes and contributed a mean delay of 44% of the total DTB time. The time course of each patient, from presentation at the referring hospital to PPCI, is summarised in Figure 2. The primary endpoint was achieved in 8\/24 cases (33%) of whom one achieved a DTB time of less than 90 minutes. A further 8\/24 (33%) cases were within 15 minutes of achieving a DTB time of 120 minutes. A DTB time of greater than 180 minutes was observed in 2\/24 patients (8%). Both patients presented outside normal working hours. Other time intervals are summarised in Table 2. Table 2. Time intervals in transfer Time interval, minutes (n=24) Value Referring hospital Symptom onset to door 1 97 (43-163) Door 1 to ECG 5 (2-7) ECG to contact helicopter 15 (9-19) Contact helicopter to departure 35 (24-46) Door 1 to departure 56 (47-63) Transport times Transfer flight time 33 (31-35) Door 1 to door 2 89 (77-98) PCI centre Door 2 to CCL 17 (15-21) CCL to balloon 19 (15-25) Door 2 to balloon 35 (31-42) Total door 1 to balloon 125 (117-147) Working hours 122 (105-136) After hours 134 (117-159) Door 1 to balloon time <90 minutes, n (%) 1 (4) Door 1 to balloon time <120 minutes, n (%) 8 (33) Values are median (interquartile range). CCL = cardiac catheterisation laboratory. No patients required resuscitation or defibrillation during helicopter transfer. The CCL was falsely activated in 2\/24 (8%) cases. In both cases, although the criteria for STEMI were not met, the patient was found to have significant obstructive disease and myocardial infarction (non-STEMI) and underwent PCI. One patient with STEMI did not undergo PCI, rather undergoing thrombus aspiration in the setting of severe 3-vessel coronary disease, before proceeding to elective inpatient coronary bypass surgery. Prior to intervention, 18\/24 (66%) patients had TIMI grade 0-1 flow. Following intervention, normal (TIMI 3) coronary flow was established in 22\/24 (92%) of the vessels undergoing intervention. The culprit artery was the left anterior descending artery in 14\/24 (58%) cases. In all cases of intervention, only the culprit vessel was treated acutely. However, 3\/23 (13%) patients undergoing PCI required staged PCI to a non-culprit lesion in another coronary artery at a later admission. Drug-eluting stents were used in 14\/23 (61%) of PCI cases. No patients required repeated percutaneous intervention during the STEMI admission although 2\/23 (8%) of the patients who underwent PCI required non-emergent coronary bypass surgery duri