Percutaneous coronary intervention for acute coronary syndrome or non–ST-elevation myocardial infarction requires the use of potent oral and intravenous anti-platelet and antithrombin medications. Although these potent antithrombotic agents and regimens may increase the effectiveness of percutaneous coronary intervention, they are also generally associated with an increased risk of vascular access complications such as hematoma, retroperitoneal hematoma, pseudoaneurysm, arterial occlusion, and arteriovenous fistula, which in turn are associated with increased morbidity, mortality, and costs. Risk factors predisposing patients to these complications are both modifiable (procedure technique, medications, hemostasis method) and nonmodifiable (sex, age, body mass index, blood pressure, renal function). Patients’ risks can be reduced by nurses who are knowledgeable about these risk factors and identify complications before they become problematic.