Anesthesia, Perfusion, and Surgical practicEs in Cardiac Surgery: an Adaptive, Prospective, International, Multicenter, Observational Study.

The perioperative management, particularly the use of anesthesia, cardiopulmonary bypass (CPB) and surgical techniques in cardiac surgery, remains highly variable across institutions and regions. Current international guidelines lack clear recommendations due to the insufficiency of high-quality comparative data. Furthermore, over two thirds of the recommendations continue to rely on expert opinion, with little change over time. Given the complexity and physiological burden of cardiac surgery, understanding global variation in anesthetic, perfusion and surgical strategies is critical.

The APECx initiative is an adaptive, international, multicenter, prospective cohort study designed to address multiple of these knowledge gaps. The study aims to promote consistent, evidence-based care by describing global practice variationsand identifying potential modifiable factors that are associated with clinical outcomes.

The core feature of the APECx study is its adaptive design that allows the research focus to evolve over time. The study will proceed through distinct phases, beginning in 2026. Each phase will span approximately one year, concluding once the phase-specific, predefined sample size is reached, at which point the study will transition to the next phase. This framework enables the collection of comprehensive data on specific practices and outcomes within a single, continuously evolving study. To ensure transparency and reproducibility, a detailed protocol for each study phase will be registered on ClinicalTrials.gov prior to phase start.

All data will be prospectively collected by local investigators and entered into a web-based electronic Case Report Form (eCRF) using Castor (Castor Electronic Data Capture, Amsterdam, the Netherlands). Data collection will occur biannually, with participating centers collecting data for a period of two consecutive weeks within a designated three-month window. Follow-up will continue for 30 days post-surgery or until hospital discharge, whichever comes first.

This study will be conducted at cardiac surgery centers worldwide. An inclusive enrollment strategy aims to recruit a broad spectrum of centers, varying in research involvement, surgical complexity, annual caseload, and geographic location, to ensure a globally representative dataset. Centers will have the flexibility to join or leave the study at the beginning of each new phase, a design feature intended to lower the threshold for participation.