Does ischaemia testing predict worse adverse outcomes in ANOCA patients?

Abstract

Abstract Background Following the recent ISCHEMIA trial (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) it was revealed that the extent of ischaemia was not associated with an increased risk for adverse outcomes after adjustment for coronary artery disease (CAD) severity. How the extent of ischemia applies to outcomes for patients with stable angina without obstructive CAD is unknown. Purpose To determine if the presence of ischaemia impacted on 3-year clinical outcomes (mortality and readmission) in patients with Angina and Non-Obstructive Coronary Arteries (ANOCA). Methods ANOCA was defined as those presenting with chest pain symptoms consistent with angina and undergoing an elective angiogram. All consecutive ANOCA (stenosis <50%) enrolled in the CADOSA (Coronary Angiogram Database of South Australia) Registry between 2012-2018 were included. CADOSA captures all public hospital patients undergoing coronary angiography. Results Among 8,932 symptomatic patients undergoing elective angiography, 1,169 patients (60±11 years, 59% female) with ANOCA underwent ischaemic stress testing prior to angiography. Of these patients, 185 (16%) had no evidence of ischaemia (ANOCA ischaemia negative), and 984 (84%) had documented evidence of ischaemia (ANOCA ischaemia positive). The ANOCA ischaemic negative patients (relative to the ANOCA ischaemic positive patients) were (a) younger (58±11 vs 61±11, p<0.05), (b) in the year preceding diagnostic angiography, more often presented to the emergency department with chest pain (36% vs 21%, p<0.05) and required hospital admission (28% vs 14%, p<0.05), and (c) had more disabling angina, as assessed by the Canadian Cardiovascular Society Score (CCSS; CCSC-IV 19% vs 13%, p>0.05). At 3-year post-angiography follow-up, (i) cardiac mortality was similar (ANOCA negative 0% vs ANOCA positive 0.1%, p>0.05), but the ANOCA negative patients were more likely to present to the emergency department (26% vs 14%, p< 0.05) and require hospital readmission (18% vs 8%), compared to the ANOCA positive patients. Conclusion Patients with ANOCA and negative ischaemic testing have more disabling symptoms, with frequent emergency department presentations and readmissions, compared to those with a positive ischaemic test. Hence the presence of ischaemia on stress testing is not predictive of clinical outcomes and further investigation is required to identify predictors of outcomes in ANOCA.