Abstract Background International guidelines have endorsed the use of edoxaban or rivaroxaban as an alternative to low-molecular-weight heparin (LMWH) for the treatment of acute venous thromboembolism (VTE) in cancer patients. Recently, a large randomized controlled trial of apixaban versus dalteparin in patients with cancer was completed. We performed an updated meta-analysis to assess the efficacy and safety of direct oral anticoagulants (DOACs) versus LMWH in patients with cancer-associated VTE. Methods MEDLINE, EMBASE, and CENTRAL (Cochrane Controlled Trials Registry) were systematically searched up to March 30, 2020 for randomized controlled trials comparing DOACs versus LMWH for the treatment of VTE in patients with cancer. The two coprimary outcomes were recurrent VTE and major bleeding at 6 months. Data were pooled by the Mantel–Haenszel method and compared by relative risk ratios (RRs) and 95% confidence intervals (CIs). Results Four randomized controlled studies (2,894 patients) comparing apixaban, edoxaban, or rivaroxaban with dalteparin were included in the meta-analysis. Recurrent VTE occurred in 75 of 1,446 patients (5.2%) treated with oral factor Xa inhibitors and in 119 of 1,448 patients (8.2%) treated with LMWH (RR 0.62; 95% CI 0.43–0.91; I 2, 30%). Major bleeding occurred in 62 (4.3%) and 48 (3.3%) patients receiving oral factor Xa inhibitors or LMWH, respectively (RR 1.31; 95% CI 0.83–2.08; I 2, 23%). Conclusion In patients with cancer-associated VTE, oral factor Xa inhibitors reduced the risk of recurrent VTE without a significantly higher likelihood of major bleeding at 6 months compared with LMWH.

Catheter ablation has gained a prominent role in the management of atrial fibrillation (AF), with recent data providing positive evidence on hard outcomes, including hospitalization and mortality. Ablation, however, exposes the patient to a rather unique situation, combining risks for both major bleeding and thromboembolic events. In this setting, the critical importance of rigorous anticoagulation during the procedure has been underlined, and the latest international guidelines now recommend performing AF catheter ablation with uninterrupted non-vitamin K antagonist oral anticoagulants (NOACs) and concomitant administration of unfractionated heparin adjusted to achieve and maintain a target activated clotting time of ≥300 seconds. Whereas observational studies and randomized controlled trials support the safety and efficacy of uninterrupted NOAC strategy for AF catheter ablation, recent experiences have questioned this point, showing a greater unfractionated heparin requirement in NOAC-treated patients compared with vitamin K antagonists–treated patients to achieve the target activated clotting time. Important gaps in evidence regarding optimal intraprocedural anticoagulation management need to be acknowledged. A thorough appreciation of the physiology of anticoagulation during AF catheter ablation and the relevant differences between vitamin K antagonists and NOACs is required, while also understanding the limitations of activated clotting time measurement with regard to accurate intraprocedural anticogulation monitoring. This review aims to provide a critical look at this relatively ignored aspect of AF catheter ablation, especially pitfalls in NOAC monitoring, and to identify gaps in knowledge that need to be addressed in the near future.