Lung function in mitral stenosis.

OBJECTIVES

The aim of this study was to look to for a relationship between pulmonary artery pressure (PAP), left atrial pressure (LAP), mitral valve area (MVA) and transmitral gradient (Gr) on the one hand and the spirometric data on the other, in cases of mitral stenosis.

METHODS

The spirometry values measured were forced vital capacity (FVC), forced expiratory volume in one second and as percent of FVC (FEV1, FEV1/FVC%), forced expiratory flow between 25% to 75% of FVC (FEF 25-75%), at 50% of FVC (FEF 50%) 75% of FVC (FEF 75%) and peak expiratory flow rate (PEFR). The PAP, LAP, MVA and Gr were measured at echocardiography and cardiac catheterisation.

RESULTS

Analysis of results was done of 60 patients in four groups divided on basis of mean PAP: Group 1 with least and group 4 with highest mean PAP. FVC values were reduced in direct proportion to PAP, LAP, MVA and Gr in three out of four groups. FEV1% as a percent of predicted value showed uniform reduction in all the groups, PEFR was moderately affected in group 1 and most severely in group 4. Values of FEV1/FVC% were within normal range in all the groups. FEF 25-75%, and FEF 50% showed serial reduction in values in keeping with the elevation of the PAP. FEF 75% was also moderately affected in group 1 and most severely in group 4.

CONCLUSION

We found that a moderate restrictive defect and a small airway defect which is found in cases of mitral stenosis, directly correlates to the PAP, LAP, MVA and Gr. There was no significant involvement of the larger airways.