A Novel Issue for Vitreoretinal Surgeons.

A Novel Issue for Vitreoretinal Surgeons For more than 20 years, medicine was limited to a few classically prescribed antithrombotic agents: the anticoagulant, warfarin, and the antiplatelet drugs, Aspirin and clopidogrel. In recent years, these classes have expanded considerably with new anticoagulant and antiplatelet medications now widely available. Dabigatran (Pradaxa; Boehringer Ingelheim Pharmaceuticals, Ingelheim am Rhein, Germany), rivaroxaban (Xarelto; Bayer Healthcare, Leverkusen, Germany), and apixaban (Eliquis; Bristol-Myers Squibb, New York, NY) are commonly referred to as “novel oral anticoagulants” or “direct oral anticoagulants. ” These medications are advantageous because they have a rapid onset of action, do not require regular monitoring of blood coagulation parameters, are less sensitive to fluctuations in patients’ diets, and cause fewer adverse bleeding events, while providing an equivalent degree of protection from thromboembolism. Conversely, it is difficult to monitor the pharmacodynamic activity of these drugs, and there are no practical means to emergently reverse their effects. Because they boast a relatively short half-life of approximately 12 hours, it can be safely assumed that their effect has ended when discontinued 1 to 2 days before a surgical procedure. All three of these medications are pharmacokinetically cleared to varying degrees through renal pathways, dabigatran to a greater extent than the other two, so patients with impaired renal function may require earlier discontinuation. Prasugrel (Effient; Eli Lilly and Company, Indianapolis, IN) and ticagrelor (Brilinta; AstraZeneca, London, United Kingdom) are the newest antiplatelet medications on the market. Like clopidogrel, they are adenosine diphosphate receptor inhibitors, but with greater affinity and faster mechanism of action. Similar to the new anticoagulant medications, the rates of hemorrhagic complications during vitreoretinal procedures have not been previously reported. Should they need to be interrupted before surgery, current recommendations are 7 days for prasugrel and 5 days for ticagrelor. Collectively, these five agents—the “novel oral anticoagulants,” dabigatran, apixaban, and rivaroxaban, and the two antiplatelet medications, prasugrel and ticagrelor—may be deemed “novel oral antithrombotics. ” There is no consensus as to whether one type is more likely to cause perioperative hemorrhage. In this issue of the journal, Grand and Walia report postvitreoretinal surgery outcomes of patients taking these antithrombotic agents. In general, they found that patients on these medications were only slightly more likely to have hemorrhagic complications after surgery. Of 36 eyes, 3 of the 4 patients with postoperative vitreous hemorrhage were taking an antiplatelet medication as opposed to an anticoagulant. None of the patients experienced permanent loss of vision. These results parallel those of a recent metaanalysis, which included all phase three randomized clinical trials comparing novel oral anticoagulants with any controls. This meta analysis reported that novel oral anticoagulants cause no greater risk for intraocular bleeding when compared with other antithrombotics. Vitreoretinal surgical procedures require informed consent and preoperative planning, especially for patients with multiple comorbidities. The surgeon is faced with the decision to continue or suspend antithrombotics, determine the duration of their discontinuation, and even consider bridging anticoagulation therapy with heparin or enoxaparin. Most of these judgments are made in conjunction with the patient’s internist or cardiologist. Discussions regarding the perioperative management of antithrombotics should include considerations of the prescribing physician and surgeon based on the potential impact on the patient. The prescriber does so with respect to the thrombogenic condition being managed and the surgeon with respect to the underlying ophthalmic disease and surgical procedure. Unlike most other ophthalmic procedures, vitreoretinal surgery is somewhat unique because it is categorized in the medical literature as “high-risk” for hemorrhagic complications, in company with neurosurgery. This stratification presumes that any perioperative bleed would likely have devastating consequences and implies that antithrombotics should be tapered or None of the authors have any financial/conflicting interests to disclose.