Kyung Hwa Choi1, Seung Ryeol Lee1, Young Kwon Hong1, Dong Soo Park2. 1. Department Urology, CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi-do, Republic of Korea. 2. Department Urology, CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi-do, Republic of Korea. Electronic address: dsparkmd@cha.ac.kr.
Abstract
OBJECTIVE: To investigate whether the postnephrectomy renal adaptation mechanism, focused on functional hyperfiltration as well as structural hypertrophy, was affected by abdominal obesity. MATERIALS AND METHODS: We retrospectively evaluated 358 patients who underwent simple or radical nephrectomy and nephroureterectomy between 2009 and 2013. Patients were classified according to waist circumference (WC), with values >102 cm in men and >88 cm in women considered high (obesity). Functional renal volume (FRV) was measured using computed tomography performed preoperatively and 6 months postoperatively to evaluate the degree of remnant kidney hypertrophy. The degree of hyperfiltration was calculated from the difference between the preoperative and postoperative glomerular filtration rate (GFR)/FRV. RESULTS: The mean preoperative GFR, FRV, and GFR/FRV were 72.1 mL/min/1.73 m2, 282.8 cm3, and 0.25 mL/min/1.73 m2/cm3, respectively. The percent GFR reduction was significantly greater in the high WC group (high, 25.9% vs normal, 16.0%, P = .036), although the degree of hypertrophic volume in the remnant kidney showed no difference. The change in GFR/FRV was statistically lower in the high WC group (high, 25.7% vs normal, 40.2%, P = .009). The factors associated with postoperative increased GFR/FRV were low preoperative GFR, proteinuria, high predictive preserved functional parenchymal volume ratio, absence of hypertension, increased levels of high-density lipoprotein cholesterol, and normal WC (all P < .05). CONCLUSION: Patients with high WC might have a large reduction in postoperative renal function, owing to a lower degree of functional hyperfiltration.
OBJECTIVE: To investigate whether the postnephrectomy renal adaptation mechanism, focused on functional hyperfiltration as well as structural hypertrophy, was affected by abdominal obesity. MATERIALS AND METHODS: We retrospectively evaluated 358 patients who underwent simple or radical nephrectomy and nephroureterectomy between 2009 and 2013. Patients were classified according to waist circumference (WC), with values >102 cm in men and >88 cm in women considered high (obesity). Functional renal volume (FRV) was measured using computed tomography performed preoperatively and 6 months postoperatively to evaluate the degree of remnant kidney hypertrophy. The degree of hyperfiltration was calculated from the difference between the preoperative and postoperative glomerular filtration rate (GFR)/FRV. RESULTS: The mean preoperative GFR, FRV, and GFR/FRV were 72.1 mL/min/1.73 m2, 282.8 cm3, and 0.25 mL/min/1.73 m2/cm3, respectively. The percent GFR reduction was significantly greater in the high WC group (high, 25.9% vs normal, 16.0%, P = .036), although the degree of hypertrophic volume in the remnant kidney showed no difference. The change in GFR/FRV was statistically lower in the high WC group (high, 25.7% vs normal, 40.2%, P = .009). The factors associated with postoperative increased GFR/FRV were low preoperative GFR, proteinuria, high predictive preserved functional parenchymal volume ratio, absence of hypertension, increased levels of high-density lipoprotein cholesterol, and normal WC (all P < .05). CONCLUSION:Patients with high WC might have a large reduction in postoperative renal function, owing to a lower degree of functional hyperfiltration.