Effect of preinfarction angina on primary percutaneous coronary intervention outcomes

Preinfarction angina has been recognized as a surrogate for preconditioning episodes. This study was designed to evaluate the cardiovascular effects of preinfarction anginal episodes among acute myocardial infarction (AMI) patients undergoing primary percutaneous coronary intervention (PCI). Of 520 patients who had undergone primary PCI, 393 patients were finally included in a prospective cohort study. Standard primary PCI procedure according to the latest guidelines was performed. The patients were divided into three groups based on previous symptoms as follows: asymptomatic (Group A), chronic stable angina (Group B) and unstable angina (Group C). A total of 393 patients were evaluated. 185 (47.1%) patients were described as asymptomatic, 48 (12.2%) had stable angina and 160 (40.7%) were categorized as unstable angina. There was no significant difference among the study groups regarding pre- and post-PCI thrombolysis in myocardial infarction flow grade (P = 0.81). Median of peak post-PCI creatine-kinase-muscle/brain level of Group A (asymptomatic) was 250.5 (115.5–389), and it was significantly higher than Group C (176 [60.00–313.50]) (P = 0.03). Q wave formation was observed in 142 (88.75%), 31 (64.5%), and 96 (52.0%) patients of Group A, B, and C patients, respectively, which was significantly higher in asymptomatic patients (P = 0.002). There was no significant difference among the three groups regarding in-hospital and 6-month mortality (P = 0.36, 0.06, respectively). The composite endpoint of 6-month mortality, acute coronary events, cerebrovascular accidents, and target vessel revascularization was not significantly different between the three groups (P = 0.11). Preinfarction angina among AMI patients undergoing primary PCI seems to have a limited beneficial effect on infarct size, and this benefit was not translated to any clinical benefit.