High Antiphospholipid Antibody Titers and Outcomes of Pulmonary Endarterectomy: A Single-Center Retrospective Observational Cohort Study

Antiphospholipid syndrome (APS) is a risk factor for chronic thromboembolic pulmonary hypertension, which is generally treated by pulmonary endarterectomy (PEA). Patients with high antiphospholipid antibody (aPL) titers may be at increased risk for post-operative thrombotic complications. The aim of this study was to investigate potential associations linking APS with high aPL titers to mortality and complications after PEA.

Data were collected retrospectively for patients with and without APS who underwent PEA over a 14-year period (2007-2020). Hemodynamic parameters were recorded before and after surgery. Patients with APS were dichotomized according to whether the aPL titer was moderate (<80 U/mL) or high (≥80 U/mL).

During the study period, of 1354 patients who underwent PEA, 56 (4.1%) had APS, including 18 (32.1%) with high aPL titers. Early hemodynamic results were similar in patients with high aPL titers, moderate aPL titers, and no APS. APS is associated with an increased risk of delirium and seizures. The only complication more common in high- vs. moderate-titer APS was thrombocytopenia <50.0 G/L (55.5% vs. 26.3%; P=0.03). Treatments for APS-related complications were required in 15 (26.8%) patients. No patients with APS died, whereas mortality was 5.4% in controls (P=0.11).

Patients with high aPL titers had similar hemodynamic results and mortality rates after PEA. Only thrombocytopenia <50.0 G/L was more common in patients with high vs. moderate titers. Our data suggest that PEA is safe in APS patients with high aPL titers. This must be weighted against the small numbers of patients.