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-MVAPHT, and -MVA3D-planimetry). MVAs were also determined by using multi-detector computed tomographic scan (MDCT) before MVRep and within 7 days after MVRep (pre- and post-MVACT). 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-MVAPHT, pre-MVA3D-planimetry and preop-MVACT (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-MVA3D-planimetry and post-MVACT (2.22 [2.07-2.36] and 2.31 [2.07-2.36] cm2, respectively) were significantly larger than post-MVAPHT (1.98 [1.83-2.13] cm2; P=0.007 and P<0.001, respectively). The correlation coefficient between post-MVA3D-planimetry and post-MVACT (0.59, P<0.01) was greater than that between post-MVAPHT and post-MVACT (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.