Angina frequency after acute myocardial infarction in patients without obstructive coronary artery disease

Abstract

Aims: Myocardial infarction (MI) patients without obstructive coronary artery disease (CAD) are at increased risk for recurrent ischaemic events, but angina frequency post-MI has not been described. Methods and results: Among MI patients who underwent angiography, we assessed angina at baseline, 1, 6, and 12 months using the Seattle Angina Questionnaire. A hierarchical repeated-measures-modified Poisson model assessed the association between the absence of obstructive CAD (defined as epicardial stenosis >70% or left main stenosis >50%) and angina. Among 5539 MI patients from 31 US hospitals (mean age 60, 68% male), 6.9% had no angiographic obstructive CAD. More patients without obstructive CAD (vs. obstructive CAD) were female (57 vs. 30%), non-white (51 vs. 24%), and had non ST elevation myocardial infarction (87 vs. 51%). In unadjusted analyses, patients without obstructive CAD had less angina prior to MI, but more angina and worse health status post-discharge. After adjustment for socio-demographic and clinical factors, the risk of post-MI angina was similar in patients without vs. with obstructive CAD [incidence rate ratio (IRR) = 0.89, 95% CI 0.77–1.02]. Among patients without obstructive CAD, depression and self-reported avoidance of care due to cost were independently associated with angina (IRR = 1.28 per 5 points on Patient Health Questionnaire, 95% CI 1.17–1.41; IRR = 1.34, 95% CI 1.02–1.1.74). Conclusion: Following MI, patients without obstructive CAD experience an angina burden at least as high as those with obstructive CAD, affecting 1 in 4 patients at 12 months. As these patients are not candidates for revascularization, other antianginal strategies are needed to improve their health status and quality of life.