Trial of iloprost versus aspirin treatment for critical limb ischaemia of thromboangiitis obliterans. The TAO Study.

152 patients with thromboangiitis obliterans (Buerger's disease) and pain from critical leg ischaemia were randomly allocated to receive iloprost, a chemically stable prostacyclin analogue, or low-dose aspirin, for 28 days in a double-blind trial. On review, 19 patients did not fulfil the stringent entry criteria. Of the other 133 patients, 98 also had leg ulcers. After 21-28 days, 58 (85%) of 68 iloprost-treated patients showed ulcer healing or relief of ischaemic pain, compared with 11 (17%) of 65 in the aspirin-treated group. 43 (63%) on iloprost treatment had complete relief of pain, compared with 18 (28%) on aspirin. Ulcers healed completely in 18 of 52 (35%) who received iloprost compared with 6 of 46 (13%) who received aspirin. 6 months after the start of treatment, the response rate was 45 of 51 (88%) patients treated with iloprost compared with 12 of 44 (21%) patients treated with aspirin.