Patients with mitral stenosis(MS) have been demonstrated to haute a variable degree of pulmonary dysfunction and exercise impairment. The hemodynamic changes of MS can be reversed after percutaneous mitral balloon valvuloplasty(PMV), but the extent and time course of the imporvement in pulmonary function and exercise capacity are not defined.

In order to investigate the early(3 weeks or less)and late(3 months or more) effects of PMV on pulmonary function and determine if the pulmonary dysfunction is reversible even in patients with moderate to severe pulmonary hypertension, we performed the spirometry, measurements of diffusing capacity and lung volumes, and incremental exercise tests in patients with MS before and after PMV.

In 46 patients with MS(age : 40±12years, male to female ratio 1:2, mitral valve area : 0.8±0.2 cm²) there was a significant increase in FVC(P<0.0025), FEV1(P<0.001), FEF_25-75%(P<0.001), FEF50%(P<0.001), PEF(P<0.0005), MVV(P<0.005), VO₂max (P<0.0001), and AT(P<0.0001) after average 10 days of PMV. Also there was a significant decrease in DLco(P<0.0001) and DL/VA(P<0.0001). At later(5±2months) follow-up in 11 patients, there was no further improvement in any parameters of pulmonary function and exercise test. Twenty nine patients with sinus rhythm were divided into 16 patients with pulmonary arterial pressure(PAP) more than 35mmHg and/or tricuspid regurgitation grade II or more(group A) and 13 Patients with PAP less than 35mmHg(group B). Group A Patients had significantly lower FVC(P<0.001), FEV1(P<0.001), DLco(P<0.05), VO₂max(P<0.025) and mitral valve area(P<0.025) than group B Patients. Group A patients after PMV, showed significant increase in FVC(P<0.001), maximum O₂ pulse(P<0.00001) and VO₂ max(P<0.00025). Both group showed an increase in AT(P<0.0001, P<0.005), but group A showed greater decrease in VE/VO₂ and VE/VCO₂ both at AT(P<0.001, P<0.001) and VO₂ max(P<0.0001, P<0.0001) after PMV compared with group B.

These data suggest that patients with MS can show increased pulmonary function and exercise performance within 1 month after PMV. Patients with moderate to severe pulmonary hypertension had a significant increase in exercise performance compared with those with mild to no pulmonary hypertension and it is thought to be related to a significat decrease of ventilation for a given oxygen consumption at maximum exercise.