Robotic Partial Nephrectomy in Patients with Chronic Kidney Disease: Objective Measurement of Short- and Long-Term Renal Functional Outcomes

Background: Minimal literature informs the use of robotic partial nephrectomy (RPN) in patients with chronic kidney disease (CKD). Therefore, we evaluated the renal functional outcomes in CKD patients undergoing RPN. Methods: We reviewed a prospective database of patients undergoing RPN 2010 to 2015 and identified 182 patients who had preoperative and postoperative nuclear renal scintigraphy (at 2 and 12 months postop). Preoperative and 12-month postoperative eGFR (mL/min/1.73m(2), by MDRD) were calculated. CKD was defined as eGFR 60mL/min/1.73m(2) (CKD stages III and IV). Changes in creatinine, eGFR, and split function on mercaptoacetyltriglycine (MAG)-3 scan were compared by baseline CKD status. Correlations between pre- and postoperative eGFR were calculated. Results: Of 182 patients, 30 (16.5%) had baseline CKD. Preoperative eGFR was 48.5 and 99.0 in CKD and non-CKD patients, respectively (p<0.001). From preoperation to 12 months postoperation, eGFR decreased by 2.8 and 1.1mL/min/1.73m(2), respectively (p=0.6). On MAG-3 scan, the contribution of the surgical kidney to overall renal function decreased by 5.0% and 4.8% (p=0.9) in the CKD and non-CKD cohorts, respectively. When comparing renal scans at 2 and 12 months postoperation, in both groups the surgical kidney significantly recovered (both p<0.001) and the patterns of kidney function recovery was similar in both groups (CKD +2.0%, non-CKD +1.4%, p=0.6). On long-term follow-up (>2 years), eGFR did not change significantly in either the CKD or non-CKD group (-2.8 vs -1.1mL/min/1.73m(2), p=0.6). On pathology, tumors were more frequently malignant in CKD vs non-CKD patients (93.3% vs 73.2%, p=0.02) and of higher Fuhrman Grade (grade 3: 49.7% vs 28.1%, p<0.001). Conclusion: RPN is a reasonable treatment option in patients with CKD, as it did not lead to a greater decline in renal function contributed by the surgical kidney. The patterns of kidney function recovery after surgery are similar between patients with and without CKD.