The current guidelines for percutaneous coronary intervention do not address the prolonged postprocedural use of unfractionated heparin (UFH) to prevent acute occlusion. However, recently published small studies have yielded mixed results, leaving the question unanswered. Hence, we performed a meta-analysis of the existing evidence to assess the safety and efficacy of prolonged infusion of UFH after percutaneous coronary intervention. A systematic review of literature revealed seven studies involving 2412 patients. End points analyzed were ischemic complications (acute closure, myocardial infarction, and repeat revascularization) and major vascular complications (hematoma, arteriovenous fistula, pseudoaneurysm, and retroperitoneal bleed). Because the studies were homogenous for outcomes, combined relative risks across all the studies and the 95% confidence intervals were computed using the Mantel-Haenszel fixed-effect model. A two-sided alpha error <0.05 was considered to be statistically significant. There were no significant differences in patient demographics between both groups. Compared with placebo, the risk of major vascular complication was significantly higher in patients getting postprocedural UFH for prolonged hours (relative risk, 2.24; confidence interval, 1.68-3.48; P = 0.001). However, the risk of ischemic complications was similar in both groups (relative risk, 0.95; confidence interval, 0.46-1.96; P = 0.89). The meta-analysis suggests that routine infusion of UFH after uncomplicated percutaneous coronary intervention may result in increased vascular complications without any reduction in incidence of ischemic complications.