Safety, tolerability, and effectiveness of anticoagulation and antiplatelet therapy in hereditary hemorrhagic telangiectasia

Background: Antithrombotic therapy (anticoagulation and antiplatelet therapy) is frequently needed in patients with hereditary hemorrhagic telangiectasia (HHT); however, data describing and guiding its use are very limited.

Objectives: To investigate the safety, tolerability, and effectiveness of antithrombotic therapy in HHT in a cohort large enough to compare agents, evaluate for baseline predictors of premature discontinuation, and evaluate hematologic support requirements and healthcare utilization before and after antithrombitc therapy initiation.

Methods: We performed a multicenter observational cohort study characterizing the outcomes of antithrombic therapy in adults with HHT.

Results: A total of 119 patients with HHT with 187 discrete antithrombotic therapy episodes were included. Of these, 59 patients (50%) dose-reduced and/or prematurely discontinued therapy (including 52 patients [44%] who discontinued) due to worsened bleeding complications. Initiation at reduced dose intensity had a similar premature discontinuation rate (49%) as initiation at standard dose intensity (43%). In a multivariable logistic model, a history of gastrointestinal bleeding was associated with 3.25-fold odds of discontinuation (p = .001). Hemoglobin was significantly lower (10.8 g/dL vs 12.2 g/dL, p < .001), and the need for hematologic support (intravenous iron and/or red blood cell transfusion) was significantly higher (29 patients vs 12 patients, p = .004) in the 3 months after antithrombotic therapy initiation vs the 3 months before; emergency department visits and hospital admissions due to bleeding also increased. The rates of dose-reduction and/or premature discontinuation were similar regardless of the anticoagulant class (warfarin, 46%; heparin-based, 48%; direct oral anticoagulants, 44%) or with multiple simultaneous agents (44%) but were slightly lower with single-agent antiplatelet therapy (37%). Thromboembolism despite receiving antithrombotic therapy was common (18 patients, 15%) with varying outcomes.

Conclusion: Antithrombotic therapy is challenging in HHT, resulting in objectively higher morbidity and health care utilization from worsened bleeding. Discontinuation rates approached 50% regardless of the dose intensity at initiation or type of antithrombotic agent used and were higher in patients with a gastrointestinal bleeding history.