Understanding the Debate on Distal Radial Access Site Selection in Coronary Intervention

The transradial approach has become the default vascular access strategy for coronary angiography and interventions, owing to its lower bleeding complications and enhanced patient comfort compared to transfemoral access.¹⁾ Recently, the distal radial artery (DRA) approach has gained popularity for its potential to preserve the proximal radial artery and reduce access-site complications, such as radial artery occlusion and bleeding.²⁾,³⁾,⁴⁾ Two distal radial access sites—the anatomical snuffbox and the dorsum of the hand—are increasingly utilized in coronary procedures. Each offers unique anatomical and clinical considerations, and current evidence does not clearly favor one approach over the other.

The study by Cho et al.,⁵⁾ published in this issue of the Korean Circulation Journal, evaluates the efficacy and safety of DRA access via the anatomical snuffbox compared to the dorsum of the hand. Utilizing data from the KODRA registry, this multicenter, prospective cohort study included 4,977 patients for efficacy analysis and 4,644 patients for safety assessment. The primary efficacy endpoint was defined as successful arterial puncture and completion of the coronary procedure without crossover. The primary safety endpoint was DRA-related bleeding.

Their analysis, encompassing nearly 5,000 patients, demonstrated that DRA access via the anatomical snuffbox was associated with a significantly higher puncture success rate compared to the dorsum approach (95.1% vs. 90.5%, p<0.001). Moreover, when considering procedural success—defined as successful puncture with completion of the coronary procedure without crossover—the anatomical snuffbox access again showed superiority (94.2% vs. 88.6%, p<0.001). These results underscore the procedural reliability of the anatomical snuffbox approach, particularly in experienced operators.

Importantly, DRA-related bleeding events did not differ significantly between the 2 groups, suggesting that both access sites maintain a similar safety profile in terms of major vascular complications. However, the study also highlights notable trade-offs that merit careful consideration. Most prominently, hemostasis time was significantly longer in the anatomical snuffbox group, with a markedly higher proportion of patients with prolonged hemostasis over 180 minutes (20.1% vs. 1.4%, p<0.001). In addition, the need for recompression during hemostasis was more frequent in the snuffbox cohort (4.0% vs. 2.2%, p=0.019). These findings suggest that while snuffbox access may offer technical advantages in procedural success, it comes at the cost of more challenging post-procedural hemostasis management.

Previous meta-analyses comparing DRA with conventional radial access have shown that DRA is associated with a lower risk of radial artery occlusion, though it may require a longer puncture time.³⁾,⁴⁾ In line with these findings, the present study reported a very low incidence of radial artery occlusion (0.2%), while puncture time and sheath insertion time were comparable between the anatomical snuffbox and dorsum approaches. A key strength of this study lies in its focus on a head-to-head comparison between 2 distal radial access techniques, using large-scale registry data to assess both efficacy and safety. By providing real-world evidence on both success and safety, this study offers practical guidance for less-experienced operators who are beginning to adopt DRA techniques. As operator experience increases and ultrasound-guided puncture becomes more routine, DRA outcomes are likely to further improve, enhancing procedural success while minimizing complications.

Despite the strength of being based on a large-scale, prospective multicenter registry, this study warrants caution in its clinical interpretation. Most notably, there was a significant imbalance in the number of cases between the groups, with the anatomical snuffbox approach accounting for 84% of the total population. This likely reflects operator preference in real-world practice but also introduces the potential for selection bias in interpreting the results. Furthermore, procedural heterogeneity—such as differences in operator experience, vascular anatomy, and hemostasis techniques—may exist between the 2 access sites, making a direct comparison in the context of coronary procedures inherently complex. Therefore, future randomized studies or comparisons conducted under standardized hemostasis protocols would be valuable for providing clearer causal inferences and establishing practical clinical guidelines.

In conclusion, this study provides compelling, real-world evidence that supports the efficacy of anatomical snuffbox access, while also reminding clinicians of the potential hemostatic limitations. Ultimately, the choice between the anatomical snuffbox and dorsum of the hand should be individualized, weighing procedural goals, patient-specific anatomy, and operator expertise.