The purpose of this study was to evaluate the feasibility and safety of implantation of unsheathed Palmaz-Schatz coronary stents introduced via the radial artery. Anticoagulation after coronary stenting carries the risk of vascular complications if large-bore guiding catheters are introduced via the femoral artery. These complications have serious local sequelae and lead to suboptimal anticoagulation and prolonged hospitalization. By combining 6F guiding catheters and low-profile dilatation catheters mounted with Palmaz-Schatz stents, smaller vessels such as the radial artery can be selected as the entry site. It is hypothesized that with this technique major puncture site-related complications rarely occur because hemostasis is easily achieved and because no veins and nerves are near this artery. With the double blood supply to the hand, radial artery occlusion is well tolerated. In 100 consecutive patients, stent implantation was attempted for 122 lesions in 104 vessels. Immediately after stent implantation and final angiography, the introducer sheath was withdrawn and intense anticoagulation and mobilization initiated. The radial artery puncture site was studied by two-dimensional and Doppler ultrasound. Successful stent implantation via the radial artery was achieved in 96 patients. In 2 patients, arterial puncture failed but was followed by successful stenting via another entry site. In 1 patient, stent implantation was achieved with a stent delivery system via the femoral artery after a failed attempt to cross the lesion with a bare stent via the radial approach, complicated by groin bleeding requiring transfusions and vascular surgery.(ABSTRACT TRUNCATED AT 250 WORDS)