[Preoperative ventilatory function tests as an aid in assessment of operative risk of prosthetic heart valve replacement (author's transl)].

The operative risk of prosthetic replacement of the mitral valve in 97 patients and of the aortic valve in 126 patients showed a good correlation with the decrease in preoperative pulmonary function (p less than 0,01). The overall mortality rate reached 12,4% respectively 13,4% during the first 28 days after surgery. Depending upon the stage of ventilatory impairment the mortality rate varied between 0 to 50% in the mitral group and between 6,5 to 50% in the aorti group. The impairment of respiratory function is caused by the disturbed hemodynamic function demonstrated by a negative correlation between pulmonary artery pressure and vital capacity.