Multicenter Randomized Evaluation of High Versus Standard Heparin Dose on Incident Radial Arterial Occlusion After Transradial Coronary Angiography: The SPIRIT OF ARTEMIS Study.

OBJECTIVES: The aim of this study was to test the hypothesis that more intensive over standard anticoagulation administered during coronary angiography would significantly reduce rates of radial artery occlusion (RAO).

BACKGROUND: RAO, although silent, remains a frequent and therefore worrisome complication following transradial coronary angiography. Anticoagulation is effective in reducing RAO, but the optimal heparin dose remains ill defined.

METHODS: In this multicenter, randomized superiority trial, a high dose (100 IU/kg body weight administered in divided doses) and a standard dose (50 IU/kg body weight) of heparin during 5- or 6-F coronary angiography were compared. A total of 3,102 patients were randomized, of whom 1,836 patients not proceeding to percutaneous coronary intervention and without need for arterial access crossover entered the trial. Post-catheterization hemostasis did not follow a rigid protocol.

RESULTS: A total of 102 early RAOs were found on ultrasonography (incidence 5.6%). In the high-dose heparin group, the rate of RAO was significantly lower compared with the standard-dose heparin group (27 [3.0%] vs. 75 [8.1%]; odds ratio: 0.35; 95% confidence interval: 0.22 to 0.55; p < 0.001), without compromising safety. The time to achieve hemostasis was similar between groups. To avoid 1 RAO, the number of patients needed to treat in the high-dose heparin group was approximately 20. These results were corroborated by our integrated database, showing an 80% reduction of forearm artery occlusions in high versus low heparin dose patients and our updated meta-analysis of randomized controlled trials demonstrating significant benefit of higher over lower anticoagulation intensity.

CONCLUSIONS: High compared with standard heparin dose significantly reduced the rate of RAO in patients undergoing coronary angiography. High-intensity anticoagulation should be considered in transradial diagnostic procedures. (High [100IU/Kg] Versus Standard [50IU/Kg] Heparin Dose for Prevention of Forearm Artery Occlusion; NCT02570243).