An Arterial Based Complexity (ABC) Scoring System to Assess the Morbidity Profile of Partial Nephrectomy

Abstract

Background Tumor characteristics affect surgical complexity and outcomes of partial nephrectomy (PN). Objective To develop an Arterial Based Complexity (ABC) scoring system to predict morbidity of PN. Design, Setting, and Participants Four readers independently scored contrast-enhanced computed tomography images of 179 patients who underwent PN. Intervention Renal cortical masses were categorized by the order of vessels needed to be transected/dissected during PN. Scores of 1, 2, 3S, or 3H were assigned to tumors requiring transection of interlobular and arcuate arteries, interlobar arteries, segmental arteries, or in close proximity of the renal hilum, respectively during PN. Outcome Measurements and Statistical Analysis Interobserver variability was assessed with kappa values and percentage of exact matches between each pairwise combination of readers. Linear regression was used to evaluate the association between reference scores and ischemia time, estimated blood loss, and estimated glomerular filtration rates (eGFR) at 6 wk and 6 mo after surgery adjusted for baseline eGFR. Fisher’s exact test was used to test for differences in risk of urinary fistula formation by reference category assignment. Results and Limitations Pairwise comparisons of readers’ score assignments were significantly correlated (all p <0.0001); average kappa = 0.545 across all reader pairs. The average proportion of exact matches was 69%. Linear regression between the complexity score system and surgical outcomes showed significant associations between reference category assignments and ischemia time (p <0.0001) and estimated blood loss (p = 0.049). Fisher’s exact test showed a significant difference in risk of urinary fistula formation with higher reference category assignments (p = 0.028). Limitations include use of a single institutional cohort to evaluate our system. Conclusions The ABC scoring system for PN is intuitive, easy to use, and demonstrated good correlation with perioperative morbidity. Patient Summary The ABC scoring system is novel anatomy-reproducible tool developed to help patients and doctors understand the complexity of renal masses and predict the outcomes of kidney surgery.

External validation of the Arterial Based Complexity (ABC) scoring system in renal tumors treated by minimally invasive partial nephrectomy

“…More recently, Spaliviero et al developed a novel scoring system to evaluate the surgical complexity and perioperative morbidity of a PN. In this system, candidates’ tumors are stratified into four different categories ground on the incremental order of visible arterial vessels on CT that required to be dissected/transected during PN.…”

“…The ABC scoring system was tested in a single‐center cohort with 179 patients underwent PN, which needs external validation. And more than half of the patients treated with OPN . In view of MIPN has been well applied in managing renal tumors, we initially assess the predictive significance of the ABC scoring system for clinically relevant outcomes in a single institution dataset including 350 patients treated with MIPN.…”

“…), who was blinded to patients’ features, surgical approach, and clinically relevant outcomes. The ABC scoring system evaluates the PN complexity ground on the arterial vascular anatomy of the kidney and stratified each renal lesion into a category of either 1, 2, 3S (sinus), or 3H (hilum) . The Table S1 shows details of the scoring system.…”

“…Nevertheless, studies have indicated that these scores were discrepant in predicting surgical outcomes of PN, result in difficulty in their universal reproducibility and applicability . Most recently, an Arterial Based Complexity (ABC) scoring system has been developed to evaluate the connection between PN complexity and perioperative morbidity . In daily clinical practice, the simplicity and intuitiveness of this system are obvious advantages.…”

Preoperative evaluation of renal artery in patients with renal tumor

“…Many systems have been applied to assess the complexity of the surgical approach, such as R.E.N.A.L nephrometry score (R.E.N.A.L) and arterial based complexity (ABC). [2,3] Furthermore, noninvasive visualization of renal arteries is widely used by computed tomographic angiography (CTA) or magnetic resonance angiography (MRA), which is very important for preoperative evaluation of the anatomy of renal tumor and detecting the exceptional artery.…”