One hundred seventy-one patients with aortic stenosis (AS) who had hemodynamic studies were evaluated by a scoring system of the seven following noninvasive variables which our laboratory had developed to estimate the severity of AS: left ventricular hypertrophy (LVH) by ECG; visible aortic valve calcification by chest x-ray examination; loudness of A2; Q to peak of systolic murmur; T-time of the carotid pulse; LV ejection time; and LVH by M-mode echocardiography. The range of the severity score is 0 to 16, and a score greater than or equal to 5 has been shown correctly to identify 93 percent of patients with severe AS (valve area less than or equal to 1.0 cm2). The present study has applied this method to the detection of progression of AS. Eleven patients (mean age, 60.4 years) were studied who had hemodynamic studies performed two to nine years apart (mean, three years). Progression of stenosis occurred in all, with an increase in mean aortic valve gradient from 23 +/- 4.7 mm Hg to 46 +/- 6.5 mm Hg (p less than 0.005). Aortic valve area decreased from 1.5 +/- 0.18 cm2 to 0.88 +/- 0.10 cm2 (p less than 0.005). Noninvasive scores increased in these patients from 0.7 +/- 0.5 to 7.1 +/- 2.3 (p less than 0.005). Thirty-five patients (mean age, 62.4 years) had repeat noninvasive studies one to six years apart (mean 3 years). Twenty-two (63 percent) had an increase in the noninvasive score of greater than or equal to 3 points, and 20 (57 percent) attained a score of greater than or equal to 5, indicating probable severe AS. The mean initial severity score was 2.2 +/- 0.3, and at the end of a mean follow-up of three years, the score was 8.3 +/- 0.6 (p less than 0.005). It is concluded that in the elderly male, progression of AS over a three-year period occurs in about 60 percent of patients, and progression can be detected by simple, noninvasive methods.