Three-dimensional transesophageal echocardiography for determination of the mitral valve area after mitral valve repair surgery for mitral stenosis

Abstract

BACKGROUND: Pressure half-time (PHT) method is usually unreliable for accurate determination of mitral valve area (MVA) immediately after surgical intervention of mitral stenosis (MS). The planimetry method using three-dimensional (3D) transesophageal echocardiography (3D-planimetery method) could enhance accurate determination of the intraoperative MVA. Authors investigated the efficacy of 3D-planimetry method in determining MVA immediately after mitral valve repair procedure (MVRep) for severe mitral stenosis (MS). METHODS: In severe MS patients undergoing elective MVRep (N.=41), intraoperative MVAs were determined by using PHT-method and 3D-planimetry method before and immediately after cardiopulmonary bypass (pre- and post-MVA(PHT), and -MVA(3D-planimetry)). MVAs were also determined by using multi-detector computed tomographic scan (MDCT) before MVRep and within 7 days after MVRep (pre- and post-MVA(cr)) MVAs determined by using three different methods were analysed. RESULTS: Mitral inflow pressure gradient (median [25th-75th percentile]) was significantly reduced after MVRep (3.0 [2.0-4.0] vs. 7.0 [6.0-9.0] mmHg; P<0.001). Pre-MVA(PHT), pre-MVA(3D-planimetry) and preop-MVA(cr) (mean [95% confidence interval]) did not differ significantly (1.08 [1.00-1.05], 1.08 [0.98-1.08], and 1.14 [1.07-1.22] cm(2), respectively), but post-MVA(3D-planimetry), and post-MVA(CT) (2.22 [2.07-2.36] and 2.31 [2.07-2.36] cm(2), respectively) were significantly larger than post-MVA(PHT) (1.98 [1.83-2.13] cm(2); P=0.007 and P<0.001, respectively). The correlation coefficient between post-MVA(3D-planimetry) and post-MVA(CT) (0.59, P<0.01) was greater than that between post-MVA(PHT) and post-MVA(CT) (0.39, P=0.01). CONCLUSIONS: These results support the clinical efficacy of 3D-planimetry for accurate evaluation of the MVA immediately after MVRep for severe MS, as a valuable alternative to PHT-method which usually underestimates MVA during this period.