Impact of Balloon Mitral Valvuloplasty on Net Atrioventricular Compliance and Echocardiographic Assessment of Mitral Valve Area by Pressure Half Time versus Proximal Isovelocity Surface Area
Background: We studied the relations between net-atrioventricular compliance (Cn) and balloon mitral valvuloplasty (BMV) and tested effects of Cn on mitral valve area by proximal isovelocity surface area (MVAPISA) and pressure half time (MVAPHT) before and after BMV.
Methods and Results:
Thirty-six BMV candidates were studied. Echocardiography was done before, immediately after BMV for all patients and 1-month after BMV for 13 patients. MVA was calculated invasively, (MVAGorlin, reference method), by planimetry (MVAPLN), in addition to PHT and PISA. Differences from MVA-PLN were calculated as d-PHT and d-PISA and Cn was calculated (1270 X (MVA-PLN/E-slope). Mean age was 36.1 ± 12.5 years, 25(69%) were females, 8(22%) were in atrial fibrillation. MVAPHT correlated with MVAGorlin after, but not before, BMV (r= 0.53, 0.240, p= 0.014, 0.202). MVAPISA correlated with MVAGorlin after and before BMV(r= 0.85, 0.89, all p<0.001). Both MVAPHT, and MVAPISA correlated with MVAPLN 1-month after BMV (r=0.58, 0.92, p<0.001, =0.048). d-PHT showed similar pattern of negative correlations with Cn before, immediately after, and 1 month after BMV (r= 0.69, 0.76, 0.69, p= <0.001,<0.001, =.013), while d-PISA did not. Cn independently predicted persistent pulmonary hypertension after BMV.
Conclusion: MVAPHT, unlike MVAPISA is extremely affected by Cn irrespective of the time of measurement in relation to BMV. Cn is a major determinant of persistent pulmonary hypertension after BMV.