Antiphospholipid syndrome (APS) is an autoimmune prothrombotic disorder that complicates anticoagulation during cardiovascular surgery requiring cardiopulmonary bypass (CPB). This systematic review aimed to characterize the anticoagulation monitoring strategies reported during CPB in patients with APS and to identify recurring limitations and clinical patterns rather than to assess comparative efficacy between management approaches.

Systematic review of published clinical studies.

Hospital-based cardiovascular surgery and perioperative care settings, including single- and multi-institutional reports.

Patients with a confirmed diagnosis of APS who underwent cardiac or cardiovascular surgery using CPB with heparin anticoagulation.

Intraoperative anticoagulation strategies during CPB, including activated clotting time (ACT)–based monitoring and adjunctive strategies such as heparin concentration monitoring (Hepcon), anti–factor Xa assays, and viscoelastic testing.

A Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020–compliant search of PubMed, Scopus, and the Cochrane Library identified 66 studies, of which 17 met the inclusion criteria. ACT monitoring was reported in 25 patients, Hepcon-guided heparin concentration monitoring in 25, and heparin-ACT titration in 1; most studies used multimodal monitoring approaches. Among 62 patients, 15 perioperative complications were reported, predominantly from a single cohort study that contributed the majority of quantitative outcome data. The aggregated data illustrated the heterogeneous use of monitoring strategies and recurrent concerns regarding the reliability of ACT alone.

Anticoagulation monitoring during CPB in patients with APS remains heterogeneous and insufficiently standardized. The available evidence does not permit conclusions regarding comparative efficacy among monitoring strategies. Instead, this review highlights recurrent limitations of ACT-based monitoring and the heterogeneous use of adjunctive modalities in reported cases, providing a conceptual framework to inform future prospective investigations.