Changes in Left Ventricular Function After Mitral Valve Repair for Severe Organic Mitral Regurgitation

摘要

Patient Population and Data CollectionEchocardiographic EvaluationLeft Ventricular Strain Assessment by Speckle Tracking AnalysisStatistical AnalysisResultsBaseline Clinical and Echocardiographic CharacteristicsChanges in Standard Echocardiographic Parameters After Mitral Valve RepairChanges in Strain Parameters After Mitral Valve RepairCommentChanges in LV Size and Function After Mitral Valve RepairAssessment of LV Global Strain Before and After Mitral Valve RepairStudy LimitationsConclusionsReferencesLimited data are available on the changes in left ventricular (LV) contractile function at long-term follow-up after mitral valve repair (MVr). Moreover, assessment of LV systolic function in patients undergoing MVr is troublesome with current methods, given that mitral regurgitation is characterized by increased preload and decreased afterload, potentially masking LV dysfunction. The aim of this study was to assess the value of LV global strain (longitudinal and circumferential) measured by speckle tracking analysis for detecting changes in contractile function after MVr.MethodsA total of 122 patients with organic mitral regurgitation who underwent successful MVr at an early stage (LV ejection fraction >60%, LV end-systolic diameter <40 mm) were included. Echocardiography was performed at baseline and at short-term (～7 days) and long-term (1 to 3 years) follow-up after MVr.ResultsAt baseline, LV ejection fraction and LV global strain were higher in patients than in 40 normal control individuals. By contrast, LV forward stroke volume was higher in control individuals than in patients. At short-term follow-up, a significant decrease in LV ejection fraction and LV global strain was noted as a consequence of changes in loading conditions. At long-term follow-up, LV ejection fraction and LV global strain improved significantly. Correction of LV strain for LV size showed a subtle impairment of myocardial contractility at baseline, which significantly improved over time after MVr, together with the improvement in LV forward stroke volume.ConclusionsMitral valve repair for organic mitral regurgitation results in a significant increase in LV myocardial contractility as measured by LV global strain corrected by LV size.CTSNet classification:35Dr Bax discloses that he has financial relationships with Biotronik, Boston Scientific, BMS Medical Imaging, St. Jude Medical, GE Healthcare, Edwards Lifesciences, and Medtronic; Dr Klautz with Edwards Lifesciences, St. Jude Medical, and Metronic; and Dr Delgado with St. Jude Medical.In the presence of severe organic mitral regurgitation (MR), the left ventricle (LV) is characterized by an increased preload, related to the chronic regurgitant volume, and by a decreased afterload, caused by the low impedance pathway of LV ejection into the left atrium. In compensated hemodynamic conditions, the forward cardiac output is therefore maintained by an increase in LV size [