QUANTITATIVE ASSESSMENT OF THE OPERATIVE RESULTS AFTER EXTENDED MYECTOMY AND SURGICAL RECONSTRUCTION OF THE SUBVALVULAR MITRAL APPARATUS INHYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY USING DYNAMIC 3-DIMENSIONAL TRANSESOPHAGEAL ECHOCARDIOGRAPHY

Objectives. The aim of this study was to examine the value of dynamic three-dimensional (3D) transesophageal echocardiography (TEE) for the postoperative evaluation after extended myectomy and surgical reconstr uction of the subvalvular mitral valve apparatus in patients with hype rtrophic obstructive cardiomyopathy (HOCM). Background. Two-dimensiona l imaging techniques such as echocardiography, computed tomography and magnetic resonance imaging have not been able to precisely quantify t he effects of surgical therapy on the morphology of the left ventricul ar outflow tract (LVOT). Methods. Multiplane TEE with 3D reconstructio n was performed in 11 patients before and after the operation and in 1 6 normal control subjects for comparison. The preoperative maxi mal sy stolic pressure gradient in the LVOT was 69 +/- 59 mm Hg. The followin g variables were measured within the dynamic 3D data set: depth, width , length and cross-sectional area (CSA) gain caused by the myectomy tr ough, minimal CSA of the LVOT at each time point and its cyclic change s and maximal mitral leaflet deviation during systole. Results. Functi onal class improved from 3.0 +/- 0.2 before the operation to 1.5 +/- 0 .6 after it. The maximal systolic pressure gradient in the outflow tra ct decreased to 26 +/- 21 mm Hg postoperatively (p < 0.001). Minimal C SA of the outflow tract increased from 1.1 +/- 1.2 to 3.8 +/- 1.9 cm(2 ) postoperatively (p < 0.001), similar to the value of the control gro up (4.2 +/- 1.5 cm(2), p = NS). The area gain due to the myectomy trou gh was 1.3 +/- 1.0 cm(2), corresponding to 48 +/- 12% of the total ope rative area difference. Maximal systolic depth of the myectomy was 7 /- 2 mm, maximal width was 20 +/- 8 mm and length was 28 +/- 7 mm. Max imal deviation of the mitral leaflets fell from 15 +/- 7 to 6 +/- 7 mm postoperatively (p < 0.01). In five patients mass measurements of the intracavitary portion of the papillary muscle (PM) revealed an increa se from 7.3 +/- 1.0 to 12.1 +/- 2.5 g due to surgical mobilization of PMs (p < 0.01). Conclusions. 3D TEE quantifies the differences in outf low tract morphology before and after surgery for HOCM. This technique may have an impact on the planning of operative interventions and all ow for the evaluation of its results. (C) 1998 by the American College of Cardiology.