All primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) were identified from the National Surgical Quality Improvement Program data set. Based on prior analyses, age ≥80 years, history of hypertension, and history of cardiac disease were evaluated as predictors of myocardial infarction and cardiac arrest using stepwise multivariate logistic regression. A series of predictive scores were constructed and weighted to identify the influence of each variable on 30-day postoperative cardiac events, while comparing with the Revised Cardiac Risk Index (RCRI).
Among 85,129 patients, age ≥80 years, hypertension, and a history of cardiac disease were all statistically significant predictors of postoperative cardiac events (0.32%; n = 275) after TKA and THA (P ≤ .02). Equal weighting of all variables maintained the highest discriminative capacity in both THA and TKA cohorts. Adjusted models explained 75% and 71% of the variation in postoperative cardiac events for those with THA and TKA, respectively, without statistically significant lack of fit (P = .52; P = .23, respectively). Conversely, the RCRI was not a significant predictor of postoperative cardiac events after TKA (odds ratio, 3.36; 95% CI, 0.19, 58.04; P = .40), although it maintained a similar discriminative capacity after THA (76%).
The current total joint arthroplasty Cardiac Risk Index score was the most economical in predicting postoperative cardiac complication after primary unilateral TKA and THA. The RCRI was not a significant predictor of perioperative cardiac events for TKA patients but performed similarly to the current model for THA.