Anatomical data obtained from 64 patients aged from 70 to 86 years with calcified and tight aortic orifice stenosis (functional area less than 1 cm2) were divided into three types according to the macroscopic appearance of the aortic valve: (1) tricuspid valve without commissural fusion: 44 cases (18 men, 26 women, mean age 76 years); (2) tricuspid valve with commissural fusion: 12 cases (8 men, 4 women, mean age 72 years); (3) calcified congenital bicuspid valve: 8 cases (6 men, 2 women, mean age 73 years). Thus, the distribution of patients by sex became the same starting from the eighth decade of life. Calcified aortic orifice stenosis (CAOS) of degenerative origin was the most common lesion (69 p. 100), with a strong female predominance. There were several differences between degenerative CAOS and bicuspid valve stenosis on the one hand and aortic orifice stenosis with commissural fusion on the other hand. In the first group, calcification did not involve the free edge of the aortic cusps, large calcifications of the mitral ring were extremely frequent, and there was little or no aortic regurgitation. Moreover, the aortic ring clearly was wider in cases with bicuspid valve. In patients with degenerative CAOS and bicuspid valve, attempts at digital dilatation by the left ventricular route succeeded in most cases in obtaining a fairly important widening of the aortic orifice by compression and/or disruption of the valvular calcium deposits, without causing significant regurgitation of injuring the valve; the cusps recovered some mobility.(ABSTRACT TRUNCATED AT 250 WORDS)