The prevalence and even the existence of Buerger's disease or thromboangiitis obliterans (TAO) are still ill-defined. The analysis of a continuous series of 127 young patients with obstructive arterial disease of the lower limbs (mean follow-up 67.7 months, lost to follow-up 13.8 %) allows the evaluation of the clinical, radiological and evolutive characteristics of the patients. The positive diagnosis of TAO relies upon the four usual criteria : onset of the disease before 40, no other vascular risk factor than smoking, popliteal or infra-popliteal arterial lesions, migrant superficial thrombosis. The patients are classified in 4 groups Group I : undisputed TAO, presence of all the criteria, 13 cases (10.2 %). Group II : probable TAO, presence of three criteria (no history of superficial thrombophlebitis), 19 cases (14.9 %). Group III : tobacco-related atheroma, presence of two criteria (age under 40, no other risk factor than smoking), suprapopliteal lesions, 17 cases (13.4 %). Group IV : precocious atheroma, presence of one criterium (age under 40), other risk factors, indifferent level of the arterial lesions, 78 cases (61.4 %). The statistical analysis relies upon the comparison of the mean values for measurable parameters (Student-Fisher), for frequencies and percentages (Chi 2 Yates-Fisher) and upon a step by step discriminant analysis between groups I and IV, groups I and II and groups III and IV. The level of significance is 5 %. The analysis points to two fundamental results : There is no significant difference either between groups I and II or between groups III and IV. Groups I and IV are significantly different for a lot of clinical, radiological and evolutive criteria. Nearly all the patients are regular smokers (table I) but the heaviest smokers are in group IV (significant difference between group I and group IV). Alcohol drinking is present in 49.3 % (group IV), 50.0 % (group III) and only in 7.7 % of group I (p < 0.05). The arterial disease begins earlier in group 1 (31.8 yrs) than in group IV (35.1 yrs). The difference is significant (table II). The initial clinical stage is more severe in TAO (trophic disorders in 53.8 % of group I) than in atheroma (trophic lesions 15.4 %). A local traumatism reveals the disease in 41.7 % of group I and in 5.7 % of group IV (p < 0.05). A history of present or past superficial thrombophlebitis exists in 40.6 % of groups I and II against 6.3 % of group III and 5.3 % of group IV (p < 0.05). Raynaud's phenomenon with or without trophic ulcers of the digits is more frequent in group 1 (38.5 %) and group II (52.6 %) than in group III (17.7 %) and group IV (15.4 %). The difference is significant between groups II and III. The arteriographic lesions (fig. 1) are popliteal or infra-popliteal in groups I and II. They are mainly proximal or multisegmentar in groups III and IV. Cork-screw collaterals are present in 58.3 % of group I, 43.8 % of group II, 18.8 % of group III and 6.8 % of group IV (p < 0.05 between groups I and IV). The rate of mortality after 5 years of follow-up reaches 14.3% for group IV, whereas it is nil for groups I and II after respectively 8 and 6 years (no significant difference). Vascular direct reconstruction (endarterectomy, grafts) is the main indication of surgery in patients with atheroma (groups III and IV). On the opposite, lumbar sympathectomy is widely used in TAO (table III). The global rate of amputations is much higher (p < 0.05) in group I (53.8 %) than in group IV (11.5 %). Most amputations in groups I and II are toe and below knee amputations (fig. 2). The whole results suggest that TAO is a true clinical entity occurring in 25 % of young patients with arterial disease of the inferior limbs. TAO and precocious atheroma are quite distinctly opposed and can be differenciated from one another if clinical, radiological and evolutive criteria are taken into account.
