What’s in a grade? Do current grading scales accurately reflect the highest impact postoperative complications of cytoreductive surgery on patient outcomes and resource utilization (067)

Abstract

<b>Objectives:</b> Surgical complication grading scales are essential to compare outcomes and guide surgical quality improvement strategies toward addressing the most impactful events. The most commonly used grading scales (Contracted Accordion Scale, Expanded Accordion Scale, Clavien Dindo Scale) for primary cytoreductive surgery (PCS) of ovarian cancer (OC) were adopted from general surgery. The correlation between complication grade and critical outcomes (mortality, non-home discharge, delayed chemotherapy, prolonged hospital stay) after PCS has not been tested. This study aimed to evaluate specific complications and components of existing grading scales to determine how well they reflect outcomes after PCS. <b>Methods:</b> A cohort of 892 patients with advanced-stage OC who underwent PCS at two institutions between 2006 and 2016 was studied. Univariate associations between index postoperative complications within 30 days of surgery (bowel leak, superficial surgical site infection [SSI], deep SSI, venous thromboembolic event [VTE], cardiac event) and outcomes were assessed using Chi-square and Fisher's exact tests. The magnitude of the impact of each postoperative complication (exposure) on adverse outcomes was assessed using risk ratio (RR) and population attributable risk (PAR). PAR estimates the proportion of adverse outcomes in a population that could be prevented by the elimination of a causal exposure. Outcomes within 30 days of PCS that were studied included prolonged length of stay (LOS), re-admittance or non-home discharge, return to the operating room, and organ failure, as well as death within 90 days of surgery. <b>Results:</b> Bowel leak was significantly associated with all outcomes except 90d mortality, and we observed a wide range of impacts on reoperation (PAF: 45.5) and organ failure (PAF:13.6). Venous thromboembolic event (considered a grade 2 complication on current scales) was significantly associated with 90d death (RR: 4.28, 1.87-9.79); however, the rarity of the event minimized its impact (PAF: -0.3 to 20.4). VTE was also significantly associated with end-organ failure (RR: 4.58, PAF: 10.4). Though rarely, cardiac event was most strongly associated with organ failure and was impactful (PAF: 19). Bowel leak, SSI (considered a grade 2 on current scales), and VTE also impacted organ failure. All complications evaluated impacted re-admit/non-home discharge to a modest degree (PAF range: 5.0-13.6). <b>Conclusions:</b> These results show that complications that received lower grades on existing grading systems have some of the highest impacts on patient outcomes. Current grading scales for reporting complications after PCS do not optimally reflect the relative impact of complications on patient outcomes or resource utilization. Developing a PCS-specific grading scale is needed to meaningfully guide future surgical quality improvement strategies toward the most impactful events.