In general, patients taking cardiac or blood pressure medications should continue their current medical regimen, including on the morning of surgery, to minimize the risk of rebound hypertension and ischemia. However, diuretics may be held the morning of surgery and resumed when the patient begins taking oral fluids postoperatively. Digoxin, which has a long half-life, may also be withheld the morning of surgery.
Guidelines for the use of prophylactic β-blockers in the perioperative period have been revised following the publication of the POISE-II (Perioperative Ischemic Evaluation) trial study and a subsequent meta-analysis of clinical trials. These trials demonstrated that although perioperative administration of β-blockers resulted in reduced incidence of acute myocardial infarction, the incidence of mortality and stroke increased within the first 30 days after surgery. The American College of Cardiology and the American Heart Association as well as the European Society of Cardiology currently recommend that β-blockers should be continued without interruption during the perioperative period in patients already taking them, but due to risk of harm, β-blocker prophylaxis therapy should not be initiated on patients undergoing low-risk surgery (eg, ophthalmic surgery).
Whether to maintain or discontinue anticoagulants or antiplatelet agents in patients planning to undergo ocular surgery depends on the nature of surgery to be performed, the risk of ophthalmic bleeding, the potential effect of bleeding on postoperative outcome of proposed surgery, and the risk of a serious or fatal thrombotic event if the anticoagulant or antiplatelet agent is discontinued. In general, because cataract surgery is usually performed via a clear corneal approach using topical anesthesia, the potential benefit of stopping anticoagulants prior to surgery to prevent ophthalmic bleeding does not outweigh the potential risk. In a published meta-analysis of 11 clinical trials, when warfarin use was continued in patients undergoing cataract surgery, although there was an increased risk of ophthalmic bleeding, the bleeding events were minor and had no impact on vision. Similarly, continued use of aspirin or clopidogrel before cataract surgery did not result in an increased risk of ophthalmic bleeding events.
The success of other ocular surgeries, such as trabeculectomy or drainage implant surgery impact, could potentially be impacted by subconjunctival and scleral bleeding (although the bleeding is generally not life-threatening). Furthermore, patients with concomitant iris neovascularization are at high risk of developing postoperative hyphema. As a result, some surgeons prefer to stop therapy with antiplatelet agents, direct anticoagulants, and warfarin prior to filtering surgeries. In a study evaluating the risk of stroke, transient cerebral ischemia, myocardial infarction, or deep venous thrombosis, no difference was demonstrated in the number of thrombotic events experienced by continuous users of aspirin or warfarin versus users who discontinued these agents prior to cataract surgery.
In theory, the same idea should apply to patients who discontinue use of direct anticoagulants before surgery. However, in patients who are on dual antiplatelet therapy (aspirin plus clopidogrel), for example, patients who have had a recent coronary event or placement of a cardiac stent, the risk of thrombosis of the stented artery leading to a potentially fatal outcome after withdrawal of these agents warrants a 1-year delay of the elective ocular surgery. Surgery may be performed sooner in patients undergoing cataract surgery in whom cessation of anticoagulants is unnecessary. If a year’s delay is not possible, surgery should be deferred at least 30 days after bare-metal stenting and at least 6 months after a drug-eluting stent is inserted.
A recent study showed a 20% lower risk of intraocular bleeding with the direct-acting anticoagulants during eye surgery when compared to warfarin. In an urgent situation in which it is necessary to reverse the effect of the thrombin inhibitor dabigatran, idarucizumab can reverse its effect within 15 minutes. Andexanet alfa was recently approved by the US Food and Drug Administration for reversal of direct factor Xa inhibitors rivaroxaban and apixaban (see Chapter 5 in this volume).
Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.