Two thousand normal subjects and 600 vascular patients, divided into 9 age groups were studied with the techniques of the "ultrasonic biopsy" based on high resolution scans of the arterial walls. Subjects in Class I had normal walls while patients in Class V were asymptomatic with complex plaques and those in Class VI were symptomatic. The variation in UB score (the score relative to the classes) with age was found to be proportional to age. Also the UB score was significantly higher in vascular patients. The incidence of occult coronary ischemia was increasingly high in the 6 classes and the incidence of cardiovascular events in 4 years was proportionally higher in Class V and VI. No events were observed in patients belonging to Class I and II. The progression of arterial changes in 4 years in the patients of each class was observed.