Real-world performance of postpericardiotomy syndrome diagnostic criteria-An analysis of the prospective Cardiovascular Research Consortium-A Prospective Project to Identify Biomarkers of Morbidity and Mortality in Cardiovascular Interventional Patients (CAREBANK) database.

Objectives: Postpericardiotomy syndrome (PPS) is a well-recognized postoperative complication in cardiac surgery. Current diagnostic criteria, however, seem to lack specificity and fail to account for common confounding factors encountered in clinical settings. Methods: We examined the performance of current PPS diagnostic criteria in a prospective cohort of 1001 patients from the CAREBANK (Cardiovascular Research Consortium-A Prospective Project to Identify Biomarkers of Morbidity and Mortality in Cardiovascular Interventional Patients) database who underwent cardiac surgery between 2016 and 2021 at a tertiary center. Considering clinical relevance together with the evaluation of coexisting confounding conditions, the patients fulfilling the criteria were divided into 4 categories: "definite PPS," "likely PPS," "unlikely PPS," and "no PPS." Results: The incidence of "definite PPS" and "likely PPS" was 4.0% each, whereas "unlikely PPS" and "no PPS" accounted for 8.7% and 83.3%, respectively. The median time to diagnosis was 42 days (interquartile range, 19-63) days for "definite PPS" and 24 days (9-49) days for "likely PPS." Patients categorized as "likely PPS" or "unlikely PPS" exhibited greater European System for Cardiac Operative Risk Evaluation II values, increased incidence of new-onset atrial fibrillation, delayed postoperative ventilation, and postoperative stroke, and elevated first-year mortality. Conclusions: Accurate diagnosis of PPS is often challenged by overlapping clinical conditions, especially in patients with multiple comorbidities. The majority of patients fulfilling current PPS diagnostic criteria have confounding explanations rather than genuine inflammatory disease. The presented 4-tier approach enhances the accuracy of distinguishing true inflammatory PPS and conditions that mimic its clinical presentation and should therefore be considered in future studies.