Defining perioperative risk after hepatectomy based on diagnosis and extent of resection

Outcomes after hepatectomy have been assessed incompletely and have not been stratified by both extent of resection and diagnosis. We hypothesized that operative risk is better assessed by stratifying diagnoses into low- and high-risk categories and extent of resection into major and minor resection categories to more accurately evaluate the outcomes after hepatectomy. ACS-NSQIP was reviewed for 30-day operative mortality and major morbidity after partial hepatectomy (PH), left hepatectomy (LH), right hepatectomy (RH), and trisectionectomy (TS). Mortality was reviewed per diagnosis. "High Risk" was defined as the diagnoses associated with the greatest mortality. Major and minor resections were defined by comparison of outcomes for extent of resection by univariate analysis. Chi-square tests, t tests, Fisher's exact tests, and multivariable logistic regression were utilized to compare the outcomes across groups. Among the 7,043 patients, the greatest mortality was observed with hepatocellular carcinoma (5.2%) and cholangiocarcinoma (8.2%), either intra- or extrahepatic, which were classified "High Risk". Metastatic disease, benign neoplasms, and gallbladder cancer had a mortality rate of 1.3, 0.5, and 1.0%, respectively, and were classified "Low Risk". PH and LH were similar statistically for operative mortality and major morbidity within respective diagnosis risk groups (Low Risk: PH vs. LH and High Risk: PH vs. LH; all p > 0.05) and were defined as "Minor Resections". Similarly, RH and TS had similar operative mortality and major morbidity within respective diagnosis risk groups (Low Risk: RH vs. TS and High Risk: RH vs. TS; all p > 0.05) and were defined as "Major Resections". Risks of major morbidity and mortality increased for both diagnoses and the extent of resection. With minor resections, mortality and major morbidity were 5 and 1.6 times greater respectively for high-risk diagnosis than for low-risk diagnosis. With major resections, mortality and major morbidity were 4 and 1.6 times greater, respectively, for high-risk diagnoses than low-risk diagnoses. With low-risk diagnoses, mortality and major morbidity were 2.9 and 1.7 times greater, respectively, for major resections than minor resections (p < 0.001). With high-risk diagnoses, mortality and major morbidity were 2.3 and 1.7 times greater, respectively, for major resections than minor resections (all p < 0.001). Regardless of the extent of resection, high-risk diagnoses were independently associated with mortality (OR = 3.2 and 3.1, respectively) and major morbidity (OR = 1.5 and 1.5, respectively). Risk of hepatectomy is better assessed when stratified by both the diagnostic risk and the extent of resection. Accurate assessment of these outcomes has significant implications for preoperative planning, informed consent, resource utilization, and inter-institutional comparisons.