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

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.