Prospective Randomized Comparison of Clamped Versus Unclamped Partial Nephrectomy

PRIMARY OBJECTIVES: I. To compare the changes in renal function (post-operative compared to pre-operative) in patients undergoing unclamped partial nephrectomy with or without controlled hypotension (Arm A) vs. those undergoing partial nephrectomy with hilar clamping (Arm B), as measured by change in estimated glomerular filtration rate (eGFR). SECONDARY OBJECTIVES: I. To compare the changes in renal function (post-operative compared to pre-operative) in patients undergoing unclamped partial nephrectomy with or without controlled hypotension (Arm A) vs. those undergoing partial nephrectomy with hilar clamping (Arm B), as measured by change in MAG3 (% of function attributed to affected kidney) and change in serum creatinine. II. To evaluate the safety of the unclamped procedure by estimating the differences in complication rates in patients undergoing unclamped partial nephrectomy with or without controlled hypotension (Arm A) vs. patients undergoing partial nephrectomy with hilar clamping (Arm B) in terms of intra-operative complications and post-operative complications. III. To evaluate the surgical effectiveness of the unclamped procedure by estimating the differences between patients undergoing unclamped partial nephrectomy with or without controlled hypotension (Arm A) vs. patients undergoing partial nephrectomy with hilar clamping (Arm B) in terms of surgical margin status, estimated blood loss, and transfusion rate (intraoperative and post-operative). TERTIARY OBJECTIVES: I. To record and compare the intrarenal blood flow and resistive index measurements in order to determine if a relationship exists between intraoperative findings and postoperative renal function. II. To quantify the amount of acute kidney injury (AKI) and compare the differences between patients undergoing unclamped partial nephrectomy with or without controlled hypotension (Arm A) vs. patients undergoing partial nephrectomy with hilar clamping (Arm B) as measured by urinary and serum biomarkers. III. To compare the effects of the unclamped procedure (Arm A) to the clamped procedure (Arm B) in patients with baseline eGFR < 60, and in patients with age >= 75 (exploratory subset analyses). OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM A: Patients undergo unclamped partial nephrectomy. Some patients may undergo unclamped partial nephrectomy with controlled hypotension. ARM B: Patients undergo clamped partial nephrectomy. After completion of study treatment, patients are followed up at 1 week and then at 1, 3, 6, and 12 months.