Intracardiac balloon pump for the relief of acute mitral regurgitation.

The goal of this study was to test the hypothesis whether a small balloon placed within the mitral orifice and pulsed in a synchronous manner could reduce the degree of acute mitral regurgitation. Previous experimental studies had shown that a similar balloon within the aortic orifice relieved satisfactorily aortic regurgitation. Acute mitral regurgitation was created in 14 dogs, and a catheter with a small polyurethane balloon on its distal end was introduced to the mitral ring through the left ventricular apex. The balloon was connected to a Datascope pump for intermittent, synchronous pulsation. Left atrial, left ventricular and aortic pressures were monitored. In three animals transesophageal echocardiography was used in addition to monitor the regurgitant transmitral flow with color Doppler image. Intermittent inflation of the balloon during systole decreased the maximum left atrial pressure from 31.83 mmHg +/- 3.48 mmHg to 23.16 +/- 3.3 mmHg (p < 0.001) and the mean left atrial pressure from 21.66 +/- 2.8 mmHg to 17.25 +/- 2.76 mmHg (p < 0.001). The systolic gradient across the mitral valve increased from 59 +/- 14.53 mmHg to 77.11 +/- 12.44 mmHg (p < 0.01). Transesophageal echocardiography showed an almost 50% decrease of the transmitral regurgitant flow. It is concluded that intermittent, systolic, synchronous balloon pulsation within the mitral orifice reduces the degree of experimental, acute mitral regurgitation.

On line echocardiography in evaluating left atrial changes in acute mitral regurgitation and in monitoring a catheter-mounted balloon for its correction.

The purpose of this study was to evaluate changes in the left atrial size in acute mitral regurgitation (AMR) and monitor its correction by a catheter-mounted balloon (B). In 16 dogs, pressure changes in the left atrium (LA) were related to LA size and regurgitant mitral flow after the production of AMR by severing the mitral cusps. TEE was used for evaluating LA area (ALA) and the mitral regurgitation flow area (AMRF). TEE was also used in monitoring the position of a catheter-mounted B inserted through the LV apex and positioned on the mitral ring to relieve AMR. The B was inflated during systole and deflated during diastole. The ALA increased by 4.89 +/- 1.21 cm2 (mean +/- 1 SD) (p < 0.001) after AMR, the AMRF increased by 3.01 +/- 0.85 cm2 (p < 0.001) and the mean atrial pressure (LAP) by 9.38 +/- 2.43 mmHg (p < 0.001). In all experiments the position of the B could be confirmed in the 2D image and in 4 the reduction of AMRF by the function of the B was documented by the colour flow Doppler. It is concluded that after AMR the size of the LA increases along with the increase in LA pressure and a phasically inflated balloon and its effect on AMR can be easily identified and monitored by TEE.