Recurrent thrombosis in patients with antiphospholipid antibodies and an initial venous or arterial thromboembolic event: A systematic review and meta‐analysis

Abstract

Background Patients with antiphospholipid antibodies (aPL) and thromboembolism (TE) are at risk for recurrent TE. Few studies, however, distinguish patients based on the initial event. Objectives We performed a systematic review and meta‐analysis to investigate patients with aPL and venous TE (VTE), provoked or unprovoked, and patients with arterial TE (ATE). Patients/Methods We conducted searches in PubMed, CINAHL, Cochrane, and EMBASE. Inclusion criteria were prospective trials or cohort studies investigating patients with aPL and ATE or VTE. Excluded studies did not provide estimated recurrence rates, did not specify whether the incident event was ATE or VTE, included patients with multiple events, or included <10 patients. Two‐year summary proportions were estimated using a random effects model. Results Ten studies described patients with VTE, 2 with ATE, and 5 with VTE or ATE. The 2‐year proportion for recurrent TE in patients with VTE who were taking anticoagulant therapy was 0.054 (95% confidence interval [CI], 0.037‐0.079); the 2‐year proportion for patients not taking anticoagulant therapy was 0.178 (95% CI, 0.150‐0.209). Most studies did not distinguish whether VTE were provoked or unprovoked. The 2‐year proportion for recurrent TE in patients with ATE who were taking anticoagulant therapy was 0.220 (95% CI, 0.149‐0.311); the 2‐year proportion for patients taking antiplatelet therapy was 0.216 (95% CI, 0.177‐0.261). Conclusions Patients with aPL and ATE may benefit from a different antithrombotic approach than patients with aPL and VTE. Prospective studies with well‐defined cohorts with aPL and TE are necessary to determine optimal antithrombotic strategies.

Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION): 10-Year Update

“…Risk stratification of APS patients can be based on the clinical and/or laboratory phenotype. From a clinical point of view, thrombotic recurrence risk may differ for patients with aPL who experience initial venous or arterial thrombotic events, demonstrated in a systematic review and meta-analysis [36]. The authors of this study suggested that prospective clinical trials are needed for different thrombotic phenotypes in patients with aPL; as also supported by our studies [11], cluster analysis provides a foundation to understand disease mechanisms, create new approaches to classification, and ultimately develop tailored management.…”

Thrombophilia testing: A British Society for Haematology guideline

“…[54][55][56][57] In patients with thrombotic APS, uncertainties remain as to the recurrence risk in patients with an initial unprovoked, compared to provoked, VTE and in those with venous compared to an initial arterial thrombosis. 58 There is increasing evidence that the recurrence risk of VTE provoked by minor risk factors is similar to that with unprovoked VTE. 59,60 Therefore, such patients may also benefit from extended anticoagulation therapy as in those with unprovoked VTE.…”

Thrombotic antiphospholipid syndrome: A practical guide to diagnosis and management

“…A recent meta-analysis reported that patients with APS who had an initial arterial thrombotic event had a recurrence rate over 2 years of 16% and 18% when taking anticoagulation or aspirin alone, respectively. The majority of patients taking anticoagulation were taking either a DOAC at a standard therapeutic dose, or warfarin with an INR range of 2.0-3.0 [66]. The numbers of patients on DOAC versus VKA were not specified.…”