Retrieval of renal function by revascularization. Study of preoperative outcome predictors

Results of renal revascularization for retrieval of function in poorly functioning kidneys are variable, but criteria for prediction of benefit and patient selection for operation are ill-defined. This report examines preoperative parameters in 64 hypertensive patients who underwent successful revascularization of poorly functioning kidneys as defined by creatinine clearance less than or equal to 15 ml/min (measured by preoperative split renal function studies [SRFS]) or preoperative serum creatinine greater than or equal to 3.5 mg/dl (range: up to 8.9 mg/dl) to identify markers of value in prediction of a beneficial response in renal function. Ages ranged from 35 to 75 years. There were 35 men and 29 women. The renovascular lesion was atherosclerotic in 58 patients and fibrodysplastic in six. Total renal artery occlusion was present in 32 cases. No urine flow was detectable before surgery on SRFS from 13 kidneys. Kidney lengths ranged from 7.7 cm to 15.1 cm. Fifty-four unilateral and 10 bilateral revascularizations were performed. A beneficial blood pressure response to operation was observed in 94%. Benefit in excretory function was determined by comparison of preoperative and postoperative data which included SRFS parameters, renal length, serum creatinine, isotopically derived split functioning renal mass, and glomerular filtration rates. Overall, 56 patients could be classified in regard to functional response. Twenty-two patients received no or minimal benefit; nine patients received modest improvement, and 25 patients exhibited more marked improvement. Statistical evaluation of preoperative anatomic and functional parameters as predictors of functional response suggested that multiple variables influence the probability of function retrieval by revascularization. Useful among these predictive variables are the status of the distal vessel beyond the occlusion, the bilaterality of reconstructable disease in azotemic patients, the amount of residual renal mass available for revascularization, and the degree of hyperconcentration of nonreabsorbable solutes from the involved kidney after surgery.