Introduction

Partial nephrectomy (PN) is now a preferred surgical option for small renal masses. However, renal parenchymal damage caused by PN has theoretic potential to induce hypertension (HT). We previously reported our preliminary findings indicating that PN could be related to the progression of HT in a small cohort (Inoue M, et al. Int J Urol. 2015). In this study, we aimed to clarify the effects of PN on the progression of HT, and investigate its risk factors in a larger cohort of patients with renal tumors.

Methods

Two hundred and ninety-five patients with renal tumors who underwent PN (N = 188) or radical nephrectomy (RN) (N = 107) between January 2012 and March 2016, and agreed to participate in this study, were enrolled. PN was carried out without vascular clamping in all but five patients (3%). We asked the participants to measure their home blood pressure (BP) in the morning and at bedtime for seven days, and to report these measurements and any use of antihypertensive medications at the time of the follow-up survey. Pre- and postoperative BP was calculated as the mean of the morning and bedtime BP measured on the day before the surgery, and the mean of all home BP measurements taken for postoperative seven days, respectively. The endpoint of this study was nephrectomy-related HT (NR-HT), defined as postoperative BP ≥ 140/90 mmHg with an increase of ≥ 20 mmHg from preoperative BP.

Results

In the PN and RN patients, the median age was 58 years and 62 years (p = 0.042), and tumor size was 2.5 cm and 5.0 cm (p < 0.001), respectively. Before the surgery, 72 (38%) of the PN patients and 42 (39%) of the RN patients were taking antihypertensive medications (p = 0.872). The median interval between the surgery and the follow-up survey was seven months. In the PN patients, mean pre- and postoperative BP was 125/74 mmHg and 129/79 mmHg, respectively, showing both systolic (p < 0.001) and diastolic BP (p < 0.001) increased significantly after the surgery. In the RN patients, there were no significant changes in BP after the surgery. Twenty (11%) of the PN patients and three (3%) of the RN patients developed NR-HT (p = 0.009). Antihypertensive medications were added postoperatively in 23 (12%) of the PN patients and six (6%) of the RN patients (p = 0.056). Multivariate analysis in the PN patients identified acute kidney injury (odds ratio (OR) 3.30, p = 0.034) and higher postoperative peak serum C-reactive protein level (OR 3.01, p = 0.026) as independent risk factors for NR-HT.

Conclusions

Postoperative HT was more common in PN patients than in RN patients. Renal parenchymal damage during PN may contribute to the progression of HT.

Funding

none