Introduction: Previous studies on functional outcomes after PN have been limited in size and potentially influenced by selection bias, as they were restricted to a minority (˜10%) of patients with both preop./postop. nuclear scans available for estimation of split-renal-function (SRF). Software now allows for parenchymal volume analysis (PVA), which provides a more accurate estimate of SRF, and also facilitates inclusion of a greater proportion of patients. The software also provides more accurate estimation of parenchymal volume loss and thereby improves evaluation of secondary factors affecting functional recovery. Our objective is to provide a more rigorous assessment of factors affecting functional recovery after PN. Methods: 1192 patients were managed with PN (2012-14) at our center and 670 (56%) had imaging and SCr before/after PN necessary for inclusion. Baseline demographics/comorbidities were assessed. The primary endpoint was recovery from ischemia (Rec-ischemia), defined as ipsilateral GFR saved normalized by parenchymal volume saved. Multivariable regression models were constructed to identify predictors of Rec-ischemia. Results: 261 and 409 patients had cold/zero or warm ischemia, with median ischemia times of 30/22 minutes, respectively. Median preop. global GFR and new-baseline GFR (NB-GFR) were 78/69*, respectively. Median ipsilateral preop. GFR and NB-GFR were 40/31*, respectively. Functional recovery correlated strongly with parenchymal volume preserved (r=0.83, p<0.001). Median decline in ipsilateral GFR associated with PN was 7.8*, with loss of parenchyma accounting for 81% of the loss. Median Rec-ischemia was 96% overall, and 96/95% in the cold/zero and warm ischemia groups, respectively. Insulin-dependent diabetes (coefficient=-6.2, p<0.001), treatment resistant hypertension (coefficient=-10.1, p<0.001), warm ischemia (coefficient=-1.6, p=0.03) and baseline GFR (coefficient=-0.05, p=0.01) independently associated with reduced Rec-ischemia. *ml/min/1.73m2 Conclusions: Our data confirms that the main determinant of functional recovery after PN is parenchymal volume preservation. A more rigorous evaluation allowed us to identify secondary factors that independently associated with impaired recovery. However, these secondary factors were altogether less impactful. SOURCE OF Funding: None
