[Early changes of respiratory function in mitral valve stenosis].

In order to detect early changes of respiratory function in patients affects by pure mitral valve stenosis, the authors selected 12 patients-non smokers, without symptoms of respiratory disease, of I and II NYHA class. In all subjects right and left cardiac catheterization and conventional spirometric measurements were performed. Then maximal mid-expiratory flow (MMEF), maximal expiratory flow at 50% of vital capacity (MEF 50%), maximal expiratory flow at 25% of vital capacity (MEF 25%), closing volume (CV) and closing capacity (CC) were determined, to find a small airways (bronchi of caliber inferior to 2 mm) disease. Whereas conventional spirometric measurements showed normal values, the small airways disease was proved by MEF 50% and MEF 25% measurements. The small airways obstruction observed by the authors may be due to: a) dilatation of pulmonary vessels because of venous congestion resulting in the compression of adjacent small airways; b) partial bronchiolar obstruction because of congestion of submucous venous plexus; c) interstitial oedema due to increase of extravascular pulmonary water because of pulmonary venous congestion.