Early changes in pulmonary functions after percutaneous balloon mitral valvotomy

ABSTRACT

The advent of percutaneous transvenous balloon valvotorny for mitral stenosis allows for study of pulmonary functions without limitation by the effect of thoracotomy. Spirometric assessment was done for 17 cases with mitral stenosis [4 males, 13 females] before and [24-48 hours] after balloon valvotomy. Immediate improvement could be detected in hemodynamics. Mitral valve area [MVA] increased from 1.02 +/- 0.12 to 1.85 +/- 0.3 cm2, [p<0.01] mean pressure gradient across the mitral valve [PG] decreased from 18 +/- 6 to 5.5 +/- 3.1 mmHg [p < 0.01] mean left atrial pressure [LAP] decreased from 29 +/- 9.7 to 12.7 +/- 8.8 mmHg [p<0.01] and mean pulmonary artery pressure [PAP] from 46.3 + 15 to 31.3 +/- 12 mmHg [p<0.01]. As regards pulmonary function, vital capacity [VC] increased from 2.2 +/- 0.7 to 2.4 +/- 0.7 litres [p<0.05]. Forced expiratory volume in the first second [FEV1], an index of gross airway obstruction showed insignificant change from 1.85 +/- 0.8 to 1.87 +/- 0.7 L/min [p>0.05]. Moreover, there was an insignificant decrease in the expiratory flow at mid expiratory flow volume curve which is an index of small airway function [FEF25-75%] from 2.06 +/- 1.2 to 1.9 +/- 1.08 L/min [p>0.05]. Rapid improvement in VC might reflect the decrease in cardiac volume, relief of pulmonary venous congestion as well as better performance of respiratory muscles which are now better perfused. Lag of changes in airway function is probably the result of residual interstitial oedema which takes sometime to resolve