A comparison of standard versus low dose heparin on access-related complications after coronary angiography through radial access: A meta-analysis of randomized controlled trials

Background: Transradial access (TRA) is preferred for coronary angiography (CA) or percutaneous coronary intervention due to reduced access-related complications, and mortality especially for patients with ST elevation myocardial infarction. Radial artery occlusion (RAO) is a known complication of TRA, and precludes its use as a future access site, conduit for coronary artery bypass grafting or for hemodialysis fistula placement. Although a standard dose (SD) heparin of 5000 Units is used during TRA, the risks of RAO and hematoma compared to lower dose (LD) remain unclear. To compare the risks of RAO and hematoma using SD vs. LD heparin after CA through TRA, we performed a meta-analysis of randomized controlled trials (RCT). Methods: We searched PubMed, EMBASE, CINAHL and CENTRAL for RCTs since inception through 06/30/2017 and used random effects model for analysis. The outcomes analyzed were RAO, hematoma formation and radial artery compression time (RACT). Results: We identified a total of 6 RCTs with a total of 2239 patients. SD heparin resulted in a trend toward a lower risk of RAO [4.2% vs. 10.7%; risk ratio (RR): 0.40, 95% confidence interval (CI): 0.16–1.0; P = 0.05], a trend toward increased risk of hematoma [2.2% vs. 1.1%; 1.83 (0.91–3.66); P = 0.09], and a longer duration of RACT [mean difference: 9.64 min (4.01–15.28); P = 0.0008] compared to LD. Conclusions: The current meta-analysis showed a trend towards reduction in the risk of RAO with the use of standard dose heparin. Larger randomized trials should explore the appropriate dosing of heparin to prevent radial artery occlusion.