Standardizing Postoperative Complications-Validating the Clavien-Dindo Complications Classification in Cardiac Surgery.

Cardiac surgery lacks a method for quantifying postoperative morbidities. The Clavien-Dindo Complications Classification (CDCC) and the Comprehensive Complication Index (CCI) were successfully implemented as outcome reporting methods in other surgical specialties. This study aims to validate these complication scales in cardiac surgery. Between 2010 and 2019, we prospectively collected data on 41,218 adult patients (73% men, mean age 67 ± 11 years) undergoing cardiac surgery at 6 university hospitals. Complications were graded using the CDCC based on the complication's treatment invasiveness with adaptations for common treatments in cardiac surgery. CCI were calculated, representing multiple complications on a scale of 0 (no complication) to 100 (death). Associations with predictors of poor outcome were assessed using mixed-effects models accounting for center as a random effect. CDCC grade was 0 in 23.0%, I in 11.4%, II in 35.3%, IIIa in 6.4%, IIIb in 2.6%, IVa in 16.1%, IVb in 2.1%, and V in 3.1%. Median CCI was 23 (9, 40). A change from lowest to highest observed CDCC grade was associated with an increase in the Society of Thoracic Surgeons mortality score from 1.1% to 4.7%, surgery duration from 177 to 233 minutes, and hospital stay from 5.2 to 17 days (all P < 0.0001). The CCI also increased with greater procedure complexity (P < 0.0001). Increase in CDCC/CCI is associated with greater comorbidities, surgery durations, lengths of stay, and procedure complexity, accurately reflecting the nuances of the adult cardiac surgery postoperative course. These have great potential for uniform outcome reporting and quality improvement initiatives.