Clinical Course and Predictors of Ischemic Mitral Regurgitation in Patients with Myocardial Infarctions of Different Localizations

Abstract

to assess the clinical course of ischemic mitral regurgitation (IMR) in patients with myocardial infarction of different localizations and reveal its mechanisms and predictors. We enrolled in this study patients with first inferoposterior myocardial infarction (IPMI) (n=77), and anteroseptal MI (ASMI) (n=79) revascularized within 12 hours after symptoms onset, as well as age, sex and weight matched healthy control subjects (n=50). Parameters of mitral structures and mitral annulus areas (MAA), left ventricular (LV) volumes (LVV) and sphericity index (SI), global (G) and segmental (S) longitudinal LV strain (GLS, SLS), papillary muscles (PM) LS (PMLS) and PM systolic dyssynchrony (PMSD) were measured by echocardiography on the 7th and 180th days of follow up. On the 7th day of follow up IMR was diagnosed more frequently in IPMI vs. ASMI (42 vs. 28%, р<0.001). In both groups patients with TIMI 0 flow before angioplasty had highest, while those with TIMI 3 flow - lowest incidence of IMR. Presence of IMR depended on collateral flow availability in vascular bed of infarct related artery. Wall motion abnormalities (WMA) of infarcted segments, MAA, posteromedial PM posterior displacement (PPMPD), SLS, PMLS, PMSD correlated with IMR in patients with IPMI on the 7th day of follow up. VLV, GLS and MAA correlated with IMR in patients with ASMI on the 7th day follow up. Patients with IPMI without IMR in 7th day did not develop IMR for 180 days of follow up while IMR developed in 19.3% of patients with ASMI without IMR at initial examination. Among patients with IPMI and ASMI 37.5% and 45.5%, respectively, of those with IMR at initial examination had no IMR after 180 days of follow up. Patients with IPMI more frequently had eccentric IMR than patients with ASMI (78 and 24%, respectively, p<0.002). At examination after 6 months WMA, MAA, PMSD, PPMPD, SLS, PMLS, PMSD correlated with IMR in patients with IPMI, while VLV, AMA, PM apical displacement (PMAD), GLS and PMSD correlated with IMR in patients with ASMI. AMA, PMAD and PMSD were predictors of IMR in patients with MI of both localizations. In addition, in patients with ASMI VLV and SI were also predictors of IMR.