Prognostic importance of vascular lesions in acute renal failure with microangiopathic hemolytic anemia (hemolytic-uremic syndrome): clinicopathologic study in 20 adults.

Renal biopsies obtained from 20 adult patients within 30 days after onset of acute renal failure with microangiopathic hemolytic anemia ("the hemolytic-uremic syndrome") were studied. Lesions were graded independently by two observers without knowledge of the clinical history. All patients who did not have refractory hypertension were treated with heparin. Ten of the patients died, and four developed end-stage renal failure requiring chronic dialysis. Six patients, however, had a relatively good outcome: two recovered completely and four developed mild-to-moderate chronic renal failure not requiring dialysis. The six patients with a good outcome had significantly less severe arterial intimal thickening on biopsy compared with the remaining patients with a poor outcome. The patients with a good outcome and those with a poor outcome did not differ in the severity of glomerular lesions. The clinical features did not allow a prediction of late outcome. These results suggest that early renal biopsies may be helpful in predicting prognosis in the "hemolytic-uremic syndrome." This clinical syndrome may occur either in apparently healthy people, or may complicate the course of a chronic essential hypertension.