Effects on Mortality and Major Bleeding of Radial Versus Femoral Artery Access for Coronary Angiography or Percutaneous Coronary Intervention: Meta-Analysis of Individual Patient Data From 7 Multicenter Randomized Clinical Trials

BACKGROUND: In some randomized clinical trials, transradial access (TRA) compared with transfemoral access (TFA) was associated with lower mortality in patients with coronary artery disease undergoing invasive management. We analyzed the effects of TRA versus TFA across multicenter randomized clinical trials and whether these associations are modified by patient or procedural characteristics. METHODS: We performed an individual patient data meta-analysis of multicenter randomized clinical trials comparing TRA with TFA among patients undergoing coronary angiography with or without percutaneous coronary intervention. The primary outcome was all-cause mortality and the co-primary outcome was major bleeding at 30 days. The primary analysis was conducted by 1-stage mixed-effects models on the basis of the intention-to-treat cohort. The effect of access site on mortality and major bleeding was assessed further by multivariable analysis. The relationship among access site, bleeding, and mortality was investigated by natural effect model mediation analysis with multivariable adjustment. RESULTS: A total of 21 600 patients (10 775 TRA, 10 825 TFA) from 7 randomized clinical trials were included. The median age was 63.9 years, 31.9% were women, 95% presented with acute coronary syndrome, and 75.2% underwent percutaneous coronary intervention. All-cause mortality (1.6% versus 2.1%; hazard ratio, 0.77 [95% CI, 0.63-0.95]; P=0.012) and major bleeding (1.5% versus 2.7%; odds ratio, 0.55 [95% CI, 0.45-0.67]; P<0.001) were lower with TRA. Subgroup analyses for mortality showed consistent results, except for baseline hemoglobin level (P_interaction=0.003), indicating that the benefit of TRA was substantial in patients with moderate or severe anemia, whereas it was not significant in patients with milder or no baseline anemia. After adjustment, TRA remained associated with 24% and 51% relative risk reduction of all-cause mortality and major bleeding, respectively. A mediation analysis showed that the benefit of TRA on mortality was only partially driven by major bleeding prevention and ancillary mechanisms are required to fully explain the causal association. CONCLUSIONS: TRA is associated with lower all-cause mortality and major bleeding at 30 days compared with TFA. The effect on mortality was driven by patients with anemia. The reduction in major bleeding only partially explains the mortality benefit. REGISTRATION: URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42018109664.