Abstract 19842: Microvascular Dysfunction in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention: No Sex Disparity

Abstract

Background: Microvascular dysfunction is highly prevalent in women and presumed secondary to hormonal fluctuations, increased vascular tone, and endothelial dysfunction. Its contribution has never been examined in the acute setting. Patients with ST-elevation myocardial infarction (STEMI) with persistent ST-elevation (ST-E) post successful primary percutaneous coronary intervention (PPCI) are at risk of in-hospital cardiac events. We used ST-E recovery on ECGs pre and post PPCI to study potential sex differences in microvascular dysfunction, in conjunction with cardiac events in a STEMI population. Methods: Retrospective analysis was conducted on consecutive STEMI patients undergoing PPCI in Vancouver between May 2007 and September 2010 with evaluable ECGs pre and post PPCI. Patients with bundle branch block were excluded. Quantification of ST-E in each lead was done by electronic calipers by investigators blinded to clinical outcomes. Univariate analysis was performed by sex, for the association between ST-E recovery in the lead with maximal ST-E and the composite of in-hospital mortality, heart failure, cardiogenic shock, and reinfarction. Results: Of our 413 patients, 23% were women. In comparing baseline characteristics, age was significantly different (mean age of females = 72 vs. males = 61, p<0.001). More female than male patients had incomplete (<50%) ST-E recovery (20.6% vs. 12.7%, p=0.052). Women with incomplete recovery had an odds ratio of 2.3 for the primary outcome, compared with 1.4 in men, which was not statistically significant between sex. The primary outcome occurred more often in women (29.9% vs. 18.0%, p=0.012), but after adjusting for age, sex difference was no longer significant. Conclusions: Female STEMI patients are older, had more incomplete ST-E recovery after PPCI and had more in-hospital cardiac events, although significance was lost after adjusting for age. The higher prevalence of microvascular dysfunction in stable women may not be a large contributor of persistent ST-E in the acute setting. The higher incidence of incomplete ST-elevation in women may be attributable to the increasing prevalence of endothelial dysfunction with age. This novel interaction should be further examined with objective measures.