The effect of laboratory evidence of renal parenchymal abnormality on the results of renal revascularization in 83 patients with renovascular hypertension was determined. Primary renal disease (PRD) was defined as an abnormal urinalysis (proteinuria, hematuria, or casts) in the absence of urinary infection, or decreased renal function (elevated serum creatinine level greater than 1.5 mg/dl and/or decreased creatinine clearance). All patients were hypertensive on medical therapy preoperatively. Patients were defined as cured if postoperative diastolic blood pressure (BP) was less than 90 mm Hg on no medication and improved if BP less than 90 mm Hg on medication. Sixty-six patients (80%) were cured or improved following revascularization. Of 45 patients (63%) with evidence of PRD preoperatively, 28 (62%) were cured or improved compared with 33 patients without PRD, of whom all (100%) were cured or improved (p less than 0.001). Each of five patients with transplant renal artery stenosis had two operations; four were cured or improved. The serum creatinine level was elevated preoperatively in 37 cases. Eighteen of the 37 (49%) improved to within normal limits following operation. Fifteen patients had simultaneous bilateral renal artery revascularization, and 12 (80%) were cured or improved. Fourteen patients (17%) had concomitant vascular procedures: aortobifemoral bypass (seven), abdominal aneurysm resection (five), femoral endarterectomy (one), and aortoiliac bypass (one). Twelve of these 15 patients had PRD, and 8 of the 12 (67%) were cured or improved. Only one death occurred in the perioperative period. Thirty-eight patients (46%) had been treated for hypertension for more than 12 months before referral.(ABSTRACT TRUNCATED AT 250 WORDS)