Eighty-one young Japanese patients with occlusive thromboaortopathy (Takayasu's disease), including nine men, were followed up prospectively for 7.4 +/- 5.8 years (mean +/- standard deviation) after the established diagnosis. These patients were classified according to the presence and severity of four major complications (Takayasu's retinopathy, secondary hypertension, aortic regurgitation and aortic or arterial aneurysm) attributed to Takayasu's disease at the time when the diagnosis was established: no complications (group I) or mild single complication (group IIa) and severe single complication (group IIb) or multiple complications (group III). When the data were analyzed with the left table method, severe events attributed to TAkayasu's disease, as well as death, were used as end points. Seven of the 81 patients were surgically treated; 2 of the 7 died and 1 had severe events postoperatively. In the remaining 74, the 10 year cumulative eventless survival rate after the diagnosis in combined groups I and IIa (44 patients) and combined groups IIb and III (30 patients) was 97.0 +/- 2.9 (mean +/- standard error of the mean) and 58.6 +/- 11.3 percent, respectively (p less than 0.002). These data are useful for predicting death or severe events, or both, and provide basic information regarding possible elective surgery for patients with this intractable disease.