Influence of sub valvular pathology on immediate results and follow up events of Inoue balloon mitral valvotomy.

We evaluated the influence of sub valvular pathology (SVP) on the immediate results and follow up events of Inoue Balloon Mitral Valvotomy (IBMY) in 206 patients with severe SVP (Group I) and compared their outcome with 206 age and sex matched patients selected from the rest of 619 patients having mild/moderate SVP (Group II). Pre-procedure echocardiographic recordings were reviewed and mitral valve morphology was evaluated using U.S. California Score. The severe SVP group had lower mitral valve areas (MVA) (0.7 cm2 vs. 0.8 cm2) and higher mean pulmonary artery pressure (MPAP) (46.3+/-16.9 mmHg vs. 40.7+/-16.25 mmHg) and mean pulmonary capillary wedge pressure (PCWP) (27.5+/-7.3 mmHg vs. 25.7+/-8.0 mmHg) (p<0.001). IBMV was done using standard technique. The procedure was technically successful in 192/206 patients (93.2%) in group I and 187/206 (91%) in group II (p=ns). The mean transmitral gradient decreased from 24.8+/-7.6 mmHg to 7.46+/-3.4 mmHg while mean PCWP fell from 27.5+/-7.3 mmHg to 12.2+/-5.6 mmHg and MPAP fell from 46.3+/-16.9 mmHg to 23.6+/-12.2 mmHg (p=<0.001). MVA increased from 0.7+/-0.2 cm2 to 1.7+/-0.4 cm2 (p=<0.001). Severe mitral regurgitation (MR) occurred in 2 patients out of which one patient, who had associated coronary artery disease, died post operatively, and moderate MR occurred in 8 patients. The results achieved in patients with severe SVP were not statistically different from those with mild/moderate SVP. The benefits achieved immediate post IBMV were sustained in 184 patients with severe SVP who were available for follow up at a mean duration of 15.2 months (range 3 months to 51 months). Thus IBMV is safe and effective in patients with severe SVP. This group of patients with severe SVP are more hemodynamically deranged pre-BMV and also achieve better hemodynamic benefit compared to those with mild/moderate SVP. Severe SVP does not have any adverse effect either on immediate results (success/occurrence of MR) or on intermediate term follow up.