Nephron-sparing Techniques Independently Decrease the Risk of Cardiovascular Events Relative to Radical Nephrectomy in Patients with a T1a-T1b Renal Mass and Normal Preoperative Renal Function

BACKGROUND: Some reports have suggested that nephron-sparing surgery (NSS) may protect against cardiovascular events (CVe) when compared with radical nephrectomy (RN). However, previous studies did not adjust the results for potential selection bias secondary to baseline cardiovascular risk. OBJECTIVE: To test the effect of treatment type (NSS vs RN) on the risk of developing CVe after accounting for individual cardiovascular risk. DESIGN, SETTING, AND PARTICIPANTS: A multi-institutional collaboration including 1331 patients with a clinical T1a-T1b N0 M0 renal mass and normal renal function before surgery (defined as an estimated glomerular filtration rate ≥60ml/min/1.73m2). INTERVENTION: RN (n=462, 34.7%) or NSS (n=869, 65.3%) between 1987 and 2013. OUTCOME MEASUREMENT AND STATISTICAL ANALYSES: CVe was defined as onset during the follow-up period of coronary artery disease, cardiomyopathy, hypertension, vasculopathy, heart failure, dysrhythmias, or cerebrovascular disease not known before surgery. Cox regression analyses were performed. To adjust for inherent baseline differences among patients, we performed multivariate analyses adjusting for all available characteristics depicting the overall and cardiovascular-specific profile of the patients. RESULTS AND LIMITATIONS: When stratifying for treatment type, the proportion of patients who experienced CVe at 1, 5, and 10 yr was 5.5%, 9.9%, and 20.2% for NSS patients compared to 8.7%, 15.6%, and 25.9%, respectively, for RN patients (p=0.001). In multivariate analyses, patients who underwent NSS showed a significantly lower risk of developing CVe compared with their RN counterparts (hazard ratio 0.57, 95% confidence interval 0.34-0.96; p=0.03) after accounting for clinical characteristics and cardiovascular profile. Limitations include the retrospective design of the study because other potential confounders may exist. CONCLUSIONS: The risk of CVe after renal surgery is not negligible. Patients treated with NSS have roughly half the risk of developing CVe relative to their RN counterparts. After accounting for clinical characteristics, comorbidities, and cardiovascular risk at diagnosis, NSS independently decreases the risk of CVe relative to RN. PATIENT SUMMARY: The risk of having a cardiovascular event after renal surgery decreases if a portion of the affected kidney is spared.