The characteristics of mitral regurgitation: Data from patients admitted following acute myocardial infarction.

Abstract

Data were collected on patients admitted to the Queen Elizabeth Hospital Birmingham with type-1 myocardial infarction during 2016 and 2017 inclusively, who were treated by percutaneous intervention and had pre-discharge transthoracic echocardiography. The data were obtained from prospectively maintained hospital databases and records. Echocardiography was performed and reported contemporaneously by accredited echocardiographers. The purpose was to understand the prevalence and characteristics of mitral regurgitation (MR) after acute MI, including patients with ST-elevation (STEMI) and non-ST elevation MI (NSTEMI). MR was observed in 294/1000 patients with the following relative severities: mild = 76%, moderate = 21%, severe = 3% [1]. MR was graded by multiparametric quantification including proximal isolvelocity surface area (PISA), vena contracta (VC), effective regurgitant orifice area (EROA) and regurgitant volume (RVol). Amongst all patients with MR (n=294), PISA was performed in 89/294 (30%), VC 75/294 (26%), EROA in 53/294 (18%) and RVol in 26/294 (9%). Amongst patients with moderate or severe MR (n=70), PISA was performed in 57/70 (81%), VC in 55/70 (79%), EROA in 46/70 (66%) and RVol in 25/70 (36%). Characteristics of MR following acute MI were also assessed including frequency of reported leaflet thickness (259/294 = 88%) and mitral annular calcification (102/294 = 35%). Furthermore, the effect of MI on pre-existing MR was investigated and patients with pre-existing MR who continue to have MR after acute MI were found to have progression of MR by one grade in approximately 25% of cases. Finally, using Cox proportional hazards univariate analysis, significant factors associated with mortality in patients with MR post-MI include age (HR 1.065; 95% CI 1.035-1.096; p<0.001), creatinine clearance, (HR 0.981; 95% CI 0.971-0.991; p<0.001), left ventricular ejection fraction (LVEF) (HR 0.966; 95% CI 0.948-0.984; p<0.001), indexed left ventricular end-diastolic volume (LVEDVi) (HR 1.016; 95% CI 1.003-1.029; p=0.018), indexed left ventricular end-systolic volume (LVESVi) (HR 1.021; 95% CI 1.008-1.034; p=0.001), indexed left atrial volume (HR 1.026; 95% CI 1.012-1.039; p<0.001), and those with intermediate likelihood of pulmonary hypertension (pHTN) (HR 2.223; 95% CI 1.126-4.390; p=0.021); or high likelihood of pHTN (HR 5.626; 95% CI 2.189-14.461; p<0.001). Age and LVEF were found to be independent predictors of mortality on multivariate analysis [1].