Ischaemic heart disease is the leading cause of death worldwide.1 Survival from coronary artery disease (CAD) has improved owing to advancements in revascularisation strategies leading to an increased incidence of people living with chronic heart failure.2 Although not a formal cardiomyopathy according to the European Society of Cardiology,3 ischaemic cardiomyopathy is a term used to describe severe left ventricular dysfunction (left ventricular ejection fraction [LVEF] ≤35%) as a result of CAD.

Coronary artery bypass grafting (CABG) in addition to guideline-directed medical therapy has been shown to reduce long-term mortality compared to medical therapy alone in the STICH (Surgical Treatment for Ischaemic Heart Failure) trial for patients with ischaemic cardiomyopathy.4 However, not all patients with ischaemic cardiomyopathy are candidates for surgical revascularisation. The role of percutaneous coronary intervention (PCI) in ischaemic cardiomyopathy is unclear, as randomised controlled trials involving PCI have not been completed. The best available observational data comes from the New York State registries comparing PCI and CABG in 4,616 patients with LVEF ≤35% and multivessel disease. At a median follow-up of 2.9 years, there was no significant difference in mortality rates. A greater risk of myocardial infarction and repeat revascularisation in the PCI group was offset by a higher risk of stroke in the CABG group.5Our study reviews the clinical characteristics of patients with ischaemic cardiomyopathy in the Auckland region and compares treatment strategies. The study population was extracted from the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry. Patients with heart failure (LVEF ≤35%) found to have significant CAD on coronary angiography between January 2014 and December 2017 were included. Significant CAD was defined as ≥50% stenosis in one or more major coronary arteries. Patients who underwent coronary angiography for acute coronary syndromes and those with non-ischaemic cardiomyopathy with bystander CAD were excluded. The study was exempt from formal ethics approval due to its retrospective nature.

Of the 262 patients identified as undergoing coronary angiography for heart failure, 111 were ischaemic cardiomyopathy. The mean age was 65.7±11.6 years, with the majority being men (n=89, 80.2%). The demographics of the study population are summarised in Table 1. There was a high prevalence of cardiovascular risk factors, and diabetes was present in 50 patients (45.0%). Optimal medical therapy (OMT) alone was the management strategy in 65.8% of patients, while 21.6% underwent CABG and 11.7% had PCI. There was no difference in baseline characteristics of patients who were revascularised (CABG or PCI) versus OMT alone. Severe left main stem or proximal left anterior descending artery stenosis were present in 48 patients (43.2%), and were more likely to be revascularised than those without (45.9% vs 25.2%, p=0.025).

Table 1: Baseline characteristics of study population.

The majority of patients were on a beta-blocker (93%) and angiotensin converting enzyme inhibitor/angiotensin receptor blocker (90%) at the time of coronary angiography. However, only 36% of patients were prescribed an aldosterone antagonist. All patients with atrial fibrillation (32, 28.8%) or left ventricular apical thrombus (6, 5.4%) received anticoagulation. The mean LVEF at baseline was 26.1±6.6%. Patients who received OMT alone had lower LVEF (25.1%) than those who had PCI (27.2%) or CABG (29.1%) but did not reach statistical significance (p=0.072). However, improvement in LVEF was seen across all groups on follow-up echocardiography (Figure 1).

Figure 1: Mean left ventricular ejection fraction on echocardiography at baseline and at first follow-up.

Major adverse cardiovascular events (MACE) was a composite of all-cause mortality, myocardial infarction (MI), hospitalisation with congestive heart failure (CHF) and unplanned revascularisation. At a maximum follow-up of five years (mean two years), MACE occurred in 58 patients (52.3%). The rates of each component of MACE at end of follow-up were: 32.4% hospitalisation with CHF, 27.0% all-cause mortality, 9.9% recurrent MI and 6.3% unplanned revascularisation. Patients who underwent CABG were four times less likely to experience MACE compared to those who received OMT alone (OR 0.25, 95%CI: 0.08–0.80, p=0.02). There was no difference in rates of MACE between the PCI and OMT groups (OR 0.81, 95%CI: 0.43–1.51, p=0.51). MACE-free survival curves are shown in Figure 2.

Figure 2: Kaplan Meier estimates of major adverse cardiovascular events for different treatment groups.

Although this study was not propensity matched, the superiority of CABG in ischaemic cardiomyopathy is consistent with current registry data and international guidelines. Studies such as the REVIVED-BCIS2 trial investigating the efficacy of PCI compared to OMT in ischaemic cardiomyopathy are ongoing.6 With the current available evidence, CABG should be the first-line treatment for ischaemic cardiomyopathy in patients with acceptable surgical risk. PCI can be considered as an alternative to CABG in ischaemic cardiomyopathy taking into consideration patient comorbidities, coronary anatomy and expected completeness of revascularisation.

Ischaemic heart disease is the leading cause of death worldwide.1 Survival from coronary artery disease (CAD) has improved owing to advancements in revascularisation strategies leading to an increased incidence of people living with chronic heart failure.2 Although not a formal cardiomyopathy according to the European Society of Cardiology,3 ischaemic cardiomyopathy is a term used to describe severe left ventricular dysfunction (left ventricular ejection fraction [LVEF] ≤35%) as a result of CAD.

Coronary artery bypass grafting (CABG) in addition to guideline-directed medical therapy has been shown to reduce long-term mortality compared to medical therapy alone in the STICH (Surgical Treatment for Ischaemic Heart Failure) trial for patients with ischaemic cardiomyopathy.4 However, not all patients with ischaemic cardiomyopathy are candidates for surgical revascularisation. The role of percutaneous coronary intervention (PCI) in ischaemic cardiomyopathy is unclear, as randomised controlled trials involving PCI have not been completed. The best available observational data comes from the New York State registries comparing PCI and CABG in 4,616 patients with LVEF ≤35% and multivessel disease. At a median follow-up of 2.9 years, there was no significant difference in mortality rates. A greater risk of myocardial infarction and repeat revascularisation in the PCI group was offset by a higher risk of stroke in the CABG group.5Our study reviews the clinical characteristics of patients with ischaemic cardiomyopathy in the Auckland region and compares treatment strategies. The study population was extracted from the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry. Patients with heart failure (LVEF ≤35%) found to have significant CAD on coronary angiography between January 2014 and December 2017 were included. Significant CAD was defined as ≥50% stenosis in one or more major coronary arteries. Patients who underwent coronary angiography for acute coronary syndromes and those with non-ischaemic cardiomyopathy with bystander CAD were excluded. The study was exempt from formal ethics approval due to its retrospective nature.

Of the 262 patients identified as undergoing coronary angiography for heart failure, 111 were ischaemic cardiomyopathy. The mean age was 65.7±11.6 years, with the majority being men (n=89, 80.2%). The demographics of the study population are summarised in Table 1. There was a high prevalence of cardiovascular risk factors, and diabetes was present in 50 patients (45.0%). Optimal medical therapy (OMT) alone was the management strategy in 65.8% of patients, while 21.6% underwent CABG and 11.7% had PCI. There was no difference in baseline characteristics of patients who were revascularised (CABG or PCI) versus OMT alone. Severe left main stem or proximal left anterior descending artery stenosis were present in 48 patients (43.2%), and were more likely to be revascularised than those without (45.9% vs 25.2%, p=0.025).

Table 1: Baseline characteristics of study population.

The majority of patients were on a beta-blocker (93%) and angiotensin converting enzyme inhibitor/angiotensin receptor blocker (90%) at the time of coronary angiography. However, only 36% of patients were prescribed an aldosterone antagonist. All patients with atrial fibrillation (32, 28.8%) or left ventricular apical thrombus (6, 5.4%) received anticoagulation. The mean LVEF at baseline was 26.1±6.6%. Patients who received OMT alone had lower LVEF (25.1%) than those who had PCI (27.2%) or CABG (29.1%) but did not reach statistical significance (p=0.072). However, improvement in LVEF was seen across all groups on follow-up echocardiography (Figure 1).

Figure 1: Mean left ventricular ejection fraction on echocardiography at baseline and at first follow-up.

Major adverse cardiovascular events (MACE) was a composite of all-cause mortality, myocardial infarction (MI), hospitalisation with congestive heart failure (CHF) and unplanned revascularisation. At a maximum follow-up of five years (mean two years), MACE occurred in 58 patients (52.3%). The rates of each component of MACE at end of follow-up were: 32.4% hospitalisation with CHF, 27.0% all-cause mortality, 9.9% recurrent MI and 6.3% unplanned revascularisation. Patients who underwent CABG were four times less likely to experience MACE compared to those who received OMT alone (OR 0.25, 95%CI: 0.08–0.80, p=0.02). There was no difference in rates of MACE between the PCI and OMT groups (OR 0.81, 95%CI: 0.43–1.51, p=0.51). MACE-free survival curves are shown in Figure 2.

Figure 2: Kaplan Meier estimates of major adverse cardiovascular events for different treatment groups.

Although this study was not propensity matched, the superiority of CABG in ischaemic cardiomyopathy is consistent with current registry data and international guidelines. Studies such as the REVIVED-BCIS2 trial investigating the efficacy of PCI compared to OMT in ischaemic cardiomyopathy are ongoing.6 With the current available evidence, CABG should be the first-line treatment for ischaemic cardiomyopathy in patients with acceptable surgical risk. PCI can be considered as an alternative to CABG in ischaemic cardiomyopathy taking into consideration patient comorbidities, coronary anatomy and expected completeness of revascularisation.