Incidence, angiographic features and outcomes of patients presenting with subtle ST-elevation myocardial infarction

Background Borderline electrocardiograms represent a challenge in ST-segment elevation myocardial infarction (STEMI) management and are associated with inappropriate discharges and delays to intervention. Objectives To assess angiographic characteristics and outcomes of patients presenting with subtle ST-elevation (STE) myocardial infarction. Methods A total of 504 consecutive patients with suspected STEMI treated by systematic primary percutaneous coronary intervention were prospectively included. Subtle STE was defined as a maximal preinterventional STE of 0.1 to 1 mm. Angiograms were interpreted by investigators unaware of the electrocardiographic data. Results The proportion of patients with subtle STE was 18.3%, 86% of them presented with Thrombolysis In Myocardial Infarction flow grade 0/1 and 91% underwent percutaneous coronary intervention. Despite having smaller infarcts, subtle STE patients associated more frequent multivessel disease (57% vs 44%, P = .02) and larger delays to reperfusion. During a follow-up of 19.0 +/- 4.9 months, the rates of death or reinfarction were similar among groups (10.0% vs 12.6%, P = .467). Subtle STE was not associated with better outcomes neither in univariate nor after adjustment in a multivariate analysis (adjusted hazard ratio 0.79, 95% CI 0.37-1.69, P = .546). Conclusions Subtle STEMI is frequent in clinical practice and is usually associated with acute total coronary occlusion. Therefore, it should be diagnosed and treated in the same expeditiously manner as marked STEMI.