Effect of atrial septal occlusion on mitral area after Inoue balloon valvotomy.

The purpose of this study was to examine the influence of the atrial communication created during transseptal passage of the Inoue balloon catheter on calculated mitral valve area after balloon valvotomy for severe mitral stenosis. Even in the absence of oxymetric evidence for a shunt, atrial septal puncture may result in left-to-right shunting of blood with reported spurious increases in postvalvotomy mitral valve area calculations ranging from 16-29% in prior studies. Occlusion of the septal puncture site after double balloon valvotomy has previously been shown to result in decreased postvalvotomy mitral valve area determinations. We evaluated 20 patients undergoing mitral dilation. Each patient had three postvalvotomy measurements made: (1) with the Inoue balloon catheter positioned across the septum, (2) during septal occlusion with a 7F balloon-tip catheter, and (3) without any catheters across the septum. With the Inoue catheter across the septum after successful valvotomy, the cardiac output was 4.6 +/- 1.5 L/min and the calculated mitral valve area was 1.7 +/- 0.5 cm2. No difference was found in either cardiac output or valve area when the septum was unobstructed by catheters. During septal occlusion, however, the postvalvotomy cardiac output decreased to 4.3 +/- 1.3 L/min (P < 0.001) and the calculated mitral area decreased by 12% to 1.5 +/- 0.5 cm2 (P < 0.001). The calculated mitral valve areas determined with the Inoue catheter in place after valvotomy were in agreement with echo derived data. Although statistically significant differences in post-Inoue valvotomy cardiac output and calculated mitral valve area were found during septal occlusion, these differences were small.(ABSTRACT TRUNCATED AT 250 WORDS)