The changing clinical spectrum of thromboangiitis obliterans (Buerger's disease). Between 1970 and 1987, 112 patients were diagnosed as having thromboangiitis obliterans (TAO). The age was 42 +/- 11 years (mean +/- SD; range, 20-75 years); 23% were women, and 7% were more than 60 years old when they were first diagnosed. Ischemic ulcerations were present in 85 (76%) patients: 24 (28%) patients with upper-extremity, 39 (46%) patients with lower-extremity, and 22 (26%) patients with both upper- and lower-extremity lesions. Ninety-one (81%) patients had rest pain, 49 (44%) patients had Raynaud's phenomenon, and 43 (38%) patients had superficial thrombophlebitis. We were able to follow up 89 of the 112 (79%) patients for 1-460 months (mean follow-up time, 91.6 +/- 84 months). Sixty-five (73%) patients had no amputations, while 24 (27%) had one or more of the following amputations: finger, six (15%) patients; toe, 13 (33%) patients; transmetatarsal, four (10%) patients; below knee, 14 (36%) patients; and above knee, two (5%) patients. Forty-three (48%) patients stopped smoking for a mean of 80 +/- 105 months (median, 46.5 months; range, 1-420 months), and only two (5%) patients had amputations after they stopped smoking, while 22 (42%) patients had amputations while continuing to smoke (p less than 0.0001). The spectrum of patients with TAO is changing in that the male-to-female ratio is decreasing (3:1), more older patients are being diagnosed, and upper-extremity involvement is commonly present. In the 48% of patients who stopped smoking, amputations and continued disease activity were uncommon. 