There is no universal consensus hitherto on the optimal choice of radial access from either the left or the right artery. Currently, this choice is largely dependent on the operator’s preference. The right radial access is generally preferred in routine clinical practice mainly due to its easier catheter manipulation for the operators from patient’s right side, and the current design of radial compression devices for the right wrist in medical market. As such, a major barrier to prevent the wide adoption of the left radial access lies in some difficulty to reach the left wrist leaning over the patient, particularly for shorter operators or in obese patients. However, a great deal of attention has been recently directed toward the left radial access, as it has an important anatomical advantage due to the vascular anatomy of epiaortic vessels with a straighter route to the left coronary ostium, which could also reduce the risk of cerebrovascular complications. The catheters in the right radial access, by contrast, must be rotated to afford the S-shaped geometry of the subclavian-innominate-aorta axis. Although clinicians 
have conducted exhaustive research regarding the comparative efficacy and safety between the left and the right radial accesses, there is still no conclusive evidence. Some studies have documented that the right radial access was associated with shorter procedure time and lower incidence of access-site complications compared with the left radial access. Contrastingly, a growing body of clinical trials have recently emerged to propose that radial access from the left artery might confer similar or even better procedural efficacy than from the right artery. Literature, being abundant with such clinical trials, paves the way to identify whichever artery is the optimal choice for radial access; however, a comprehensive evaluation on this topic so far is lacking. To shed some light on this issue, we sought to summarize available randomized clinical trials to compare the left with the right radial access for the diagnostic or interventional coronary procedures via a meta-analysis. Predefined subgroup AbMole Butylhydroxyanisole analyses were conducted a priori according to the ethnicity of trial patients, the purpose of cardiac catheterization, and the identity of the operators. Influential analyses were performed to assess the contribution of individual trials to pooled effect estimates by sequentially omitting each trial one at a time and computing AbMole Sarafloxacin HCl differential estimates for remaining trials. Meta-regression analyses were conducted to evaluate the extent to which different trial-level variables, including all characteristics of trial patients as mentioned above, explained the heterogeneity of pooled effects of coronary procedures on the outcomes examined.