Effects of percutaneous mitral valvuloplasty on pulmonary venous flow velocities in patients with mitral stenosis

Song, Jae Kwan; Park, Seung Jung; Park, Seong Wook; Kim, Jae Joong; Kim, Won Ho; Doo, Young Chul; Lee, Jong Koo

Abstract

BACKGROUND
Recent development of transesophageal echocardiography(TEE) makes it possible to record pulmonary venous flow velocities(PVFV) accurately. To observe the differences of PVFV between normal controls and patients with severe mitral stenosis and to clarify the effects of percutaneous mitral valvuloplasty(PMV) on PVFV, TEE was performed in 12 normal controls and 11 patients with severe mitral stenosis. METHODS: PVFV was recorded from left upper pulmonary vein in longitudinal view of midesophageal position with a 5 MHz probe. Peak velocity and velocity-time integral(VTI) of systole and diastole were calculated with a digitizer. TEE was performed before and one day after PMV. Hemodynamic data(left atrial pressure, transmitral diastolic pressure gradient and cardiac output) were analyzed to demonstrate the possible correlation with PVFV. RESULTS: 1) 75%(9/12) of normal controls showed 4 distinct phases of PVFV with 2 systolic forward peaks, I diastolic forward and I end-diastolic backward peak. Peak systolic velocity was 52.6+/-.9cm/sec and peak diastolic forward velocity was 36.0+/-10.3cm/sec : Systolic VTI was greater than diastolic VTI, too(11.1+/-3.6cm vs 5.2+/-.6cm). 2) In patients with tight mitral stenosis(mean mitral area : 0.9cm2), most(10/11, 91%) showed one peak of systolic forward flow : Peak systolic velocity(27.8+/-15.8cm/sec) and systolic velocity-time integral(3.4+/-1.8cm)were significantly smaller than those of normal controls, while there was no statistical difference in peak diastolic forward velocity and velocity-time integral(34.5+/-12.7cm/sec, 4.3+/-1.7cm) compared to normal controls. There were no significant differences according to the rhythm. After successful PMV(mean mitral valve area : 1.9cm2) peak systolic and diastolic velocities increased up to 46.9+/-13.8cm/sec, 41.4+/-7.5cm/sec respectively, and systolic increase was statistically significant. The systolic increase of peak pulmonary venous velocity and velocity-time integral was more prominent in normal sinus group compared to patients with atrial fibrillation. 3) In patients with mitral stenosis, there was no correlation between peak diastolic forward velocity of pulmonary vein and peak transmitral early diastolic velocity(r=-0.19, p=0.40) : There was a weak negative correlation between mean left atrial pressure and peak systolic velocity of pulmonary vein(r=-0.46, p=0.03) in the pooled data of pre- and postvalvuloplasty(N=22). Also there noticed a negative correlation between diastolic transmitral pressure gradient and peak diastolic velocity of pulmonary vein(r=-0.49, p=0.02, N=22). CONCLUSION: Pulmonary venous velocities of patients with tight mitral stenosis showed decreased peak systolic velocity and VTI due to increased left atrial pressure and decreased compliance. which normalized immediately after successful PMV. In patients with mitral stenosis there seems to be somewhat different relationships between hemodynamic indices and pulmonary venous flow velocities, and further study with more patients with variable mitral valve area would be necessary to clarify the exact correlation.