Balloon mitral valvuloplasty in low gradient severe rheumatic mitral stenosis: Immediate and short-term outcomes

Efficacy of balloon mitral valvuloplasty (BMV) in low gradient severe rheumatic mitral stenosis (MS) is not very well defined. This study was undertaken to evaluate the outcomes of BMV in low gradient severe rheumatic MS.

Severe MS was defined as mitral valve area < 1.5 cm². Low gradient was defined as mean diastolic trans-mitral gradient (MG) < 10 mmHg and low flow as stroke volume index < 35 ml/m² on echocardiography. Sixty patients were divided into normal-flow/low-gradient (NFLG) (40) and low-flow/low-gradient (LFLG) (20) groups. Post-BMV parameters were recorded after 72 h and at the end of one year.

Mean age was 36.2 ± 6.6 years in NFLG group and 40.6 ± 2.6 years in LFLG group (p < 0.01) and females were 75 % (n = 30) in NFLG group as compared to 60 % (n = 12) in LFLG group. Patients in the LFLG group had higher Wilkins score (p < 0.02) and prevalence of atrial fibrillation (n = 8, 40 %) as compared to NFLG group (n = 7, 17.5 %; p < 0.01). A greater decrease in MG was observed in NFLG group (p < 0.01), whereas increase in MVA was comparable in both the groups (p > 0.05). Ninety percent (n = 36) patients improved in NFLG group in comparison to 70 % (n = 14) in LFLG group (p < 0.01). At the end of one-year, symptomatic improvement persisted in all patients who became asymptomatic post-BMV.

Symptomatic improvement following BMV was better seen in NFLG group because of greater decrease in MG in comparison to LFLG group. Results of BMV were suboptimal in LFLG group because of higher sub-valvular obstruction, increased age and higher prevalence of AF.