The use of perioperative antithrombotics in posterior segment ocular surgery.

require serial monitoring of coagulation parameters. 3 Vitreoretinal surgeons are often faced with the dilemma of deciding whether to continue or suspend antithrombotic therapy prior to surgery. Although preoperative discontinuation may diminish the potential for perioperative ocular hemorrhage, it may also increase the probability for systemic complications such as stroke and myocardial infarction. 4‐6 In this regard, it is useful to assign individual patient and procedural risk factors according to a high or low level of risk for thromboembolic complications. 7 Assessment of patient risk factors should be based on an internist’s recommendations and consideration should be given to the underlying condition for which the patient is receiving anticoagulants. For example, patients prophylactically taking antithrombotics for atherosclerosis or a family history of heart disease may be candidates for interval suspension of therapy. Conversely, patients receiving treatment for conditions including the recent placement of a drug-eluting stent, new-onset atrial fibrillation, mechanical heart valves, deep vein thrombosis, or pulmonary embolism may be at substantially greater risk of thrombosis if therapy is interrupted. Hemorrhagic risks associated with vitreoretinal surgery includehyphemaandsubretinal,suprachoroidal,andvitreous hemorrhages. Prevalence of hemorrhagic complications may vary among different systemic conditions and their effect on vitreoretinal anatomy. For instance, a vascular disease such as diabetic retinopathy poses significantly different risks as compared to rhegmatogenous retinal detachment repair. One may logically infer that these complications are more prevalent in patients taking antithrombotic agents; however, thisassumptionisnotconsistentlysupportedbytheliterature. Some studies failed to demonstrate higher rates of intraoperativeorpostoperativebleedinginpatientsreceivinganticoagulants, 8 while another reported the converse. 9 Similarly, platelet inhibition has not been conclusively proven to increase the risk of vitreoretinal surgical bleeding events. The clinical significance of hemorrhage associated with platelet inhibition has, for the greater part, been minimal, with spontaneous resolution and no long-term sequelae. 9‐11 Newer surgical techniques, such as microincisional surgery, and shorter operating times may further reduce the incidence of perioperative bleeding and should diminish the importance attached to discontinuation of antithrombotic therapy. Posteriorsegmentsurgeryismostcommonlyperformedunderregionalanesthesiawithaperibulbarorretrobulbarblock. Hemorrhagic complications associated with these blocks are rare and range from mild periorbital ecchymosis and subconjunctivalhemorrhagetosight-threateningretrobulbarbleeds. The incidence of retrobulbar hemorrhage following an ophthalmic block is exceptionally low 12 and rarely of any long-term adverse functional significance. Although antithrombotics would theoretically be expected to amplify bleeding from a block, there are no evidence-based data to substantiate this; one study found that the risk was the same whether these drugs were held or sustained. 13