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

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-planmetry). MVAs were also determined by using multi-detector computed tomographic scan (MDCT) before MVRep and within 7 days after MVRep (pre- and post-MVA_CT). MVAs determined by using three different methods were analysed. RESULTS: Mitral inflow pressure gradient (median [25^th-75^th percentile]) was significantly reduced after MVRep (3.0 [2.0-4.0] vs. 7.0 [6.0-9.0] mmHg; P<.001). Pre-MVA_PHT, pre-MVA_{3D-planimetry}and preop-MVA_CT (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] cm², respectively), but post-MVA_3planimetry and post-MVA_CT(2.22 [2.07-2.36] and 2.31 [2.07-2.36] cm², respectively) were significantly larger than post-MVA_PHT (1.98 [1.83-2.13] cm²; P=0.007 and P<.001, respectively). The correlation coefficient between post-MVA_{3D-planimetry} and post-MVA_CT (0.59, P<.01) was greater than that between post-MVA_PHT and post-MVA_CT (0.39, P<.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.