Effects of Mitral Balloon Valvuloplasty on Coronary Blood Flow and Flow Reserve

While the effects of percutaneous mitral balloon valvuloplasty (PMBV) on left ventricular, right ventricular, left atrial and right atrial functions have been well demonstrated, the effects on coronary flow velocity remain unclear. The study aim was to evaluate the effects of PMBV on coronary flow velocity and flow velocity reserve in patients with mitral stenosis (MS).

A total of 32 symptomatic patients (22 females, 10 males; mean age 41.2 years) with moderate or severe isolated rheumatic MS (valve area <1.5 cm2) detected by planimetric methods was included in the study. The left anterior descending (LAD) artery flows were evaluated by coronary presets and pulsed-wave Doppler echocardiography. Hyperemic diastolic coronary flow velocities were evaluated under basal conditions and after intravenous dipyridamole, and the coronary flow velocity reserve was calculated. At seven days after PMBV the coronary flow velocity and flow velocity reserve were re-evaluated, and values obtained pre- and post-PMBV were compared.

The pre- and post-PMBV basal diastolic flow velocities were 22.6 ± 5.1 cm/s and 33.0 ± 7.9 cm/s, respectively (p = 0.030), while hyperemic diastolic flow velocities were 45.8 ± 10.0 cm/s and 53.7 ± 11.5 cm/s, respectively (p = 0.003). The systolic and diastolic peak flow velocities were significantly increased compared to the pre-PMBV values, whereas there was no significant change in diastolic coronary flow velocity reserve (2.04 ± 0.55 versus 1.83 ± 0.28, p = 0.265).

PMBV increases coronary flow in isolated MS without affecting coronary flow reserves. The low coronary flow velocities may be a reason for the subclinical left ventricular dysfunction that occurs in isolated MS.