Utility of Unfractionated Heparin in Transradial Cardiac Catheterization: A Systematic Review and Meta-analysis

Background: Unfractionated heparin (UFH) is purported to reduce the risk of radial artery occlusion (RAO) after transradial cardiac catheterization. However, the efficacy and optimal dose remain unclear. This meta-analysis evaluates the safety and efficacy of UFH in this context. Methods: MEDLINE, EMBASE, ISI Web of Science, and the Cochrane Registry were searched from 1948-May 2017. Studies investigating UFH for reducing RAO in transradial coronary catheterization were included. Data were combined using a random-effects model. Results: Of 220 citations, 8 studies (6 randomized, 2 nonrandomized; 2937 patients) were included. Two studies comparing UFH and no UFH (n = 778) found no significant benefit of UFH in reducing RAO (odds ratio [OR], 0.24; 95% confidence interval [CI], 0.01-4.67; P = 0.34; I-2 = 97%). Studies comparing higher-dose (5000 IU) and lower-dose (2,000-3,000 IU) UFH (n = 2475) found a reduction in RAO with higher-dose UFH but significant heterogeneity was demonstrated (OR, 0.28; 95% CI, 0.12-0.64; P = 0.003; I-2 = 82%). These studies were stratified by study method: for nonrandomized studies (n = 411), a lower rate of RAO was observed with no heterogeneity (OR, 0.14; 95% CI, 0.07-0.28; P < 0.001; I-2 = 0%); for randomized studies (n = 2064), a borderline significant reduction was also noted, but significant heterogeneity was demonstrated (OR, 0.37; 95% CI, 0.14- 0.99; P = 0.05; I-2 = 84%). There was a trend toward more bleeding events with highdose UFH ( OR, 1.75; 95% CI, 0.93-3.29; P = 0.08; I-2, 0%). Conclusions: Observational studies suggest a benefit of higher-dose vs lower- dose UFH in reducing RAO. However, this is less clear in randomized trials. Adequately powered randomized studies are required to determine the role of UFH in preventing RAO in transradial cardiac catheterization.