Despite recent advances in interventional cardiology, vascular access complications continue to be a significant problem. Conventional manual compression of the femoral access site is associated with prolonged immobilization and significant patient discomfort. We investigated the performance of a collagen-based closure device applied immediately after catheterization and its complication rate in 1,317 consecutive patients undergoing cardiac catheterization or coronary angioplasty. Patients undergoing coronary angioplasty (n = 644) received more heparin than patients with diagnostic cardiac catheterization (n = 673; 9,675 +/- 19144 IU vs. 6,419 +/- 2,211 IU; P < 0.0001). Deployment success rates of the closure device were comparable for patients undergoing diagnostic vs. interventional procedures (95.8% vs. 96.7%; P = 0.46). Complete hemostasis immediately after deployment of the device was achieved in > 90% of all patients, but was lower in the interventional group (93.7% vs. 90.6%; P = 0.05). Major complications including any vascular surgery, major bleeding requiring transfusion, retroperitoneal hematoma, thrombosis or loss of distal pulses, groin infections, significant groin hematoma, and death were observed in 0.53% of all patients, with no differences between diagnostic or interventional patients (0.62% vs. 0.45%; P = 0.953). Subgroup analysis revealed female gender as a predictor of access site complications. Systematic sealing of femoral access sites after both diagnostic and interventional procedures allows for immediate sheath removal with reliable hemostasis. The use of a collagen-based closure device is associated with a low rate of clinically significant complications. (C) 2002 Wiley-Liss, Inc.