**Background:** The use of antiplatelet and anticoagulant drugs is highly prevalent in the elderly population, who also frequently require vitreoretinal surgery. No large prospective randomized clinical trials have been conducted on the relative risk of using these agents perioperatively in vitreoretinal surgery, leading to high variability among eye departments in preoperative drug management. Discontinuation of blood thinners before surgery carries a risk of cardiovascular accidents, while bridging with low-dose unfractionated heparin may insufficiently reduce thromboembolic events and increase bleeding risk. This systematic review analyzes available literature to draw evidence-based conclusions on best practices for these patient groups.
**Methods:** A systematic review was conducted following PRISMA guidelines. A literature search was performed on 30 December 2022 in Ovid Medline, Embase, Cochrane Register of Controlled Trials, and Cochrane Database of Systematic Reviews using controlled vocabulary for “vitreoretinal surgery”, “vitrectomy”, “retina”, “retinal diseases”, “antiplatelet”, and “anticoagulant”. No restrictions on language, publication type, study design, or publication date were applied. Three reviewers independently screened titles and abstracts, then full texts of selected articles. Inclusion criteria were studies investigating antiplatelet and/or anticoagulant administration in patients undergoing vitreoretinal surgery and assessing bleeding-related complications. Exclusion criteria included review studies, pilot studies, case series with fewer than 12 patients, case reports, photo essays, non-English studies, animal studies, cadaveric studies, and pediatric studies. Level of evidence was assessed using Oxford Centre for Evidence-Based Medicine 2011 guidelines, and quality using the GRADE system.
**Key Results:** From 2310 articles, after removing duplicates and screening abstracts, 1839 articles remained. Twenty-seven articles were selected for full-text review, and 22 ultimately met inclusion criteria. The studies were highly heterogeneous in design, drugs used, surgical procedures, and outcomes, precluding meta-analysis. Key findings from individual studies include: Narendran et al. (2003) reported warfarin was linked to bleeding complications (relative risk 6.185). Dayani et al. (2006) found no hemorrhagic risk during the procedure itself, with increased postoperative hemorrhage being self-limiting. Fu et al. (2007) concluded successful visual and anatomical outcomes are possible in patients on warfarin. Brown et al. (2011) found no increase in perioperative hemorrhage in diabetic vitrectomies for patients on anticoagulants/antiplatelets. Fabinyi et al. (2011) reported increased risk of persistent bleeding and need for reoperation in patients on therapy at time of surgery (OR = 4.8, p = 0.0045 for persistent bleeding; OR = 6.6, p = 0.024 for reoperation). Mason et al. (2011) found very low incidence of hemorrhagic sequelae with 25-gauge PPV in patients on warfarin or clopidogrel. Passemard et al. (2012) found no significant difference in moderate/severe postoperative hemorrhagic complications across groups, but antiplatelet users had more potentially blinding complications (p = 0.003). Ryan et al. (2013) found no cases of significant postoperative choroidal bleeding or uncontrolled intraoperative hemorrhages. Brillat et al. (2015) found aspirin not significantly linked to bleeding complications (p = 0.8). Grand et al. (2016) reported no subretinal, suprachoroidal, or retrobulbar bleeding in patients on novel oral anticoagulants. Ajudani et al. (2017) found no significant difference in bleeding incidence between aspirin and control groups (p = 0.1). Meillon et al. (2018) found neither antiplatelet nor anticoagulant drugs were linked to hemorrhagic complications. Bemme et al. (2020) found no statistically significant increase in perioperative hemorrhages with ASA 100 mg or phenprocoumon. Louison et al. (2020) found no difference in ocular bleeding problems between therapy groups. Lauermann et al. (2021) found serious intraoperative bleeding episodes were not significantly affected by antiplatelet/anticoagulant use. Starr et al. (2021) found no increased risk of postoperative intraocular bleeding with direct oral anticoagulants (1.29% vs 1.41%). Guise et al. (2022) reported negligible risk of hemorrhagic complications with continued use of non-vitamin K oral anticoagulants.
**Clinical Implications:** The literature nearly unanimously recommends that patients continue taking antiplatelets and/or anticoagulants during vitreoretinal surgery. This practice does not increase the risk of hemorrhagic complications requiring a second surgery, both in pars plana vitrectomy and scleral buckle procedures. Continuing therapy reduces time between diagnosis and surgery and maintains high protection from cardioembolic accidents. The review highlights that stopping these drugs may lead to dreadful systemic complications, and the sentiment that there is no need for stopping these agents is increasingly becoming part of common practice. Limitations include potential language bias from English-only articles and considerable heterogeneity among studies.