Invasive versus medically managed acute coronary syndromes with prior bypass (CABG-ACS): insights into the registry versus randomised trial populations

Abstract

Background: Coronary artery bypass graft (CABG) patients are under-represented in acute coronary syndrome (ACS) trials. We compared characteristics and outcomes for patients who did and did not participate in a randomised trial of invasive versus non-invasive management (CABG-ACS).

Methods: ACS patients with prior CABG in four hospitals were randomised to invasive or non-invasive management. Non-randomised patients entered a registry. Primary efficacy (composite of all-cause mortality, rehospitalisation for refractory ischaemia/angina, myocardial infarction (MI), heart failure) and safety outcomes (composite of bleeding, stroke, procedure-related MI, worsening renal function) were independently adjudicated.

Results: Of 217 patients screened, 84 (39%) screenfailed, of whom 24 (29%) did not consent and 60 (71%) were ineligible. Of 133 (61%) eligible, 60 (mean±SD age, 71±9 years, 72% male) entered the trial and 73 (age, 72±10 years, 73% male) entered a registry (preferences: physician (79%), patient (38%), both (21%)).Compared with trial participants, registry patients had more valve disease, lower haemoglobin, worse New York Heart Association class and higher frailty.At baseline, invasive management was performed in 52% and 49% trial and registry patients, respectively, of whom 32% and 36% had percutaneous coronary intervention at baseline, respectively (p=0.800). After 2 years follow-up (694 (median, IQR 558-841) days), primary efficacy (43% trial vs 49% registry (HR 1.14, 95% CI 0.69 to 1.89)) and safety outcomes (28% trial vs 22% registry (HR 0.74, 95% CI 0.37 to 1.46)) were similar. EuroQol was lower in registry patients at 1 year.

Conclusions: Compared with trial participants, registry participants had excess morbidity, but longer-term outcomes were similar.

Trial registration number: NCT01895751.

Keywords: acute coronary syndrome; coronary angiography; coronary artery bypass; health care; myocardial infarction; outcome assessment.

Conflict of interest statement

Competing interests: CB is employed by the University of Glasgow, which holds consultancy and/or research agreements with companies that have commercial interests in the diagnosis and treatment of ischaemic heart disease, including Abbott Vascular, AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, HeartFlow, Menarini Farmaceutica, Opsens, Philips and Siemens Healthcare. There are no other relevant personal disclosures.

© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.

Figures

Figure 1

CONSORT diagram in CABG-ACS. CABG, coronary artery bypass graft; CONSORT, Consolidated Standards of Reporting Trials; NSTE-ACS, non-ST segment elevation acute coronary syndrome.

Figure 2

Kaplan-Meier survival curves: during a median of 694 (IQR 558–841) days follow-up: (A) The primary efficacy outcome occurred in 26 (43%) and 36 (49%) of trial and registry participants, respectively, HR 1.14, 95% CI 0.69 to 1.89. (B) The primary safety outcome occurred in 17 (28%) and 16 (22%) of trial and registry participants, respectively, HR 0.74, 95% CI 0.37 to 1.46. (C) The primary efficacy and safety outcome occurred in 10 (17%) and 8 (11%) of trial and registry participants, respectively, HR 0.64, 95% CI 0.25 to 1.63. (D) The primary efficacy or safety outcome occurred in 33 (55%) and 44 (60%) of trial and registry participants, respectively, HR 1.05, 95% CI 0.67 to 1.65.