Invasive Versus Medical Management in Patients With Prior Coronary Artery Bypass Surgery With a Non-ST Segment Elevation Acute Coronary Syndrome

Abstract

Background: The benefits of routine invasive management in patients with prior coronary artery bypass grafts presenting with non-ST elevation acute coronary syndromes are uncertain because these patients were excluded from pivotal trials.

Methods: In a multicenter trial, non-ST elevation acute coronary syndromes patients with prior coronary artery bypass graft were prospectively screened in 4 acute hospitals. Medically stabilized patients were randomized to invasive management (invasive group) or noninvasive management (medical group). The primary outcome was adherence with the randomized strategy by 30 days. A blinded, independent Clinical Event Committee adjudicated predefined composite outcomes for efficacy (all-cause mortality, rehospitalization for refractory ischemia/angina, myocardial infarction, hospitalization because of heart failure) and safety (major bleeding, stroke, procedure-related myocardial infarction, and worsening renal function).

Results: Two hundred seventeen patients were screened and 60 (mean±SD age, 71±9 years, 72% male) were randomized (invasive group, n=31; medical group, n=29). One-third (n=10) of the participants in the invasive group initially received percutaneous coronary intervention. In the medical group, 1 participant crossed over to invasive management on day 30 but percutaneous coronary intervention was not performed. During 2-years' follow-up (median [interquartile range], 744 [570-853] days), the composite outcome for efficacy occurred in 13 (42%) subjects in the invasive group and 13 (45%) subjects in the medical group. The composite safety outcome occurred in 8 (26%) subjects in the invasive group and 9 (31%) subjects in the medical group. An efficacy or safety outcome occurred in 17 (55%) subjects in the invasive group and 16 (55%) subjects in the medical group. Health status (EuroQol 5 Dimensions) and angina class in each group were similar at 12 months.

Conclusions: More than half of the population experienced a serious adverse event. An initial noninvasive management strategy is feasible. A substantive health outcomes trial of invasive versus noninvasive management in non-ST elevation acute coronary syndromes patients with prior coronary artery bypass grafts appears warranted.

Clinical trial registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01895751.

Keywords: acute coronary syndrome; clinical trial; coronary angiography; coronary artery bypass surgery; myocardial infarction; percutaneous coronary intervention.

Figures

Figure 1.

CONSORT flow diagram. CABG indicates coronary artery bypass graft.

Figure 2.

Clinical case. A 51-y-old male was hospitalized following an acute non-ST elevation acute coronary syndrome. A, Twelve-lead ECG demonstrated atrial fibrillation with ST depression and T-wave inversion in the lateral leads, which were not significantly changed from previous ECGs. The Global Registry of Acute Coronary Events score for death or myocardial infarction within 6 mo was 107. The past medical history included coronary artery bypass grafting 14 y previously, left ventricular systolic dysfunction, a cardiac defibrillator for primary prevention, and atrial fibrillation. The surgical record and graft history were not available. The day after admission to hospital, the patient provided written informed consent to participate in the CABG-ACS (coronary artery bypass graft acute coronary syndrome) trial, and he was randomized to the invasive group. Coronary angiography was performed on an urgent basis via the left radial artery. B, The native left main coronary artery was occluded at the ostium (white arrow). C, The saphenous vein grafts to the right coronary artery (RCA; red arrow) and obtuse marginal branch of the left coronary artery (orange arrow) were also occluded. D, Angiography of the native RCA revealed proximal and mid-vessel occlusions associated with bridging ipsilateral collateral connections (green arrow). E, The left internal mammary artery (LIMA) graft had a 70% to 80% stenosis (dark red arrow) involving the anastomosis with the left anterior descending (LAD) coronary artery with normal antegrade flow. This lesion was judged to be the culprit. The LIMA supplied collaterals to the distal branches of the RCA pointing to a large territory of jeopardized myocardium. Given the history of left ventricular dysfunction, the ischemic area-at-risk, and risks of percutaneous coronary intervention (PCI) to this stenosis, the treatment plan was for deferred management including uptitration of antiangina drug therapy and PCI to the LIMA should symptoms became refractory. F, Two mo later, the patient was readmitted because of persistent angina, and PCI to the insertional stenosis of the LIMA-LAD anastomosis stenosis was then performed (yellow arrow). Following predilatation, a 3.0×28 mm drug eluting stent was deployed at 17 atm. PCI was completed with high inflation postdilatation and an excellent final result was obtained. G, Angiography at the end of the procedure revealed antegrade filling of the distal LAD and retrograde filling of the posterior descending branch of the RCA via collateral connections from the LIMA-LAD system (light green arrow). Dual antiplatelet therapy was prescribed for 12 mo. The patient was hospitalized on 3 further occasions. He experienced a type 1 non-ST elevation myocardial infarction 4 mo later. In-stent restenosis was diagnosed and treated with additional PCI. Two mo later, he was then hospitalized with unstable angina and 2 mo after that he experienced another type 1 NSTEMI. He was medically managed on these occasions.

Figure 3.

Kaplan-Meier survival curves for time to occurrence of the composite outcomes for efficacy and safety, by study group.