Predictors of myocardial functional recovery following successful reperfusion of acute ST elevation myocardial infarction.

Abstract

Following acute ST elevation myocardial infarction (STEMI), restoration of large-vessel patency does not mean complete perfusion recovery. Little is known regarding the predictors of successful myocardial reperfusion for the STEMI patients undergoing pharmacologic and mechanical reperfusion strategies. The aim of this clinical study was to find out the predictors of myocardial functional recovery following reperfusion of acute STEMI, represented by 3-month global longitudinal strain (GLS) value assessed by speckle tracking echocardiography. The study population included 400 patients presented with first acute STEMI with successful reperfusion by thrombolysis (group I) or primary percutaneous coronary intervention (PPCI) (group II). Electrocardiography (ECG) at baseline and 90minutes after coronary reperfusion was performed with assessment of ST resolution. Basal and 3-month follow-up echocardiography was performed with assessment of ejection fraction (EF), myocardial performance index (MPI), systolic myocardial excursion (S'), and GLS. There was nonsignificant difference between patients of both groups regarding age (P=0.422) and gender (P=0.272). Also, there was a nonsignificant difference between both groups regarding the risk factors of coronary artery disease like hypertension (P=0.511), diabetes mellitus (P=0.332), and smoking (P=0.381). But there was significant statistical difference between both groups regarding dyslipidemia (P=0.012). Ninety-minute ST resolution was significantly higher in PPCI group (P=0.042). Moreover, PPCI group had significant improvement of EF (P=0.013) during follow-up, and highly significant improvement of MPI, S' and GLS (P˂0.001) compared to the basal echocardiographic study. The percentage of change (∆) of each of the echocardiographic parameter was compared between both groups and revealed statistically significant improvement regarding EF, highly significant improvement of MPI, S' and GLS in favor of PPCI arm (group II). Multivariate regression analysis demonstrated that pain to reperfusion time, MI territory, ST resolution, and basal GLS value are the most important predictors for LV functional recovery. The study found pain to reperfusion time, MI territory, ST resolution, basal GLS value are the most important predictors of myocardial functional recovery. Regular follow-up with echocardiography for STEMI patients with different reperfusion strategies has informative impact on long-term clinical outcome. Also the study confirmed that PPCI is better than thrombolysis not only in restoring epicardial coronary flow but also in restoring microvascular and tissue perfusion assuring better myocardial functional recovery and better long-term clinical outcomes.