The use of distal radial artery access for percutaneous coronary intervention (PCI) comes at the expense of a higher crossover rate than conventional, transradial artery access, but may offer a simpler and shorter haemostasis process.
These were among the findings gleaned from the randomised, international, multicentre DISCO RADIAL trial, which compared the two approaches in more than 1,300 patients in 15 centres in Europe and Japan. Findings from DISCO RADIAL were presented by Adel Aminian (Centre Hospitalier Universitaire de Charleroi, Charleroi, Belgium) during a late-breaking trial session at EuroPCR 2022 (17–20 May, Paris, France). Findings were simultaneously published in JACC: Cardiovascular Interventions.
Aminian told EuroPCR attendees that both approaches yielded equally “very low” incidence of forearm radial artery occlusion, but conceded that distal radial access was not superior to conventional radial access with respect to forearm radial artery occlusion, which was the primary endpoint of the trial.
“Everything in interventional cardiology starts with vascular access and finishes with vascular access,” commented Aminian, presenting his findings during a press conference at EuroPCR 2022. “We know that the radial artery is becoming the first choice as standard access for coronary procedures, owing to increased safety. This recommendation is endorsed by the most recent European and US guidelines, so this is really the standard now in all cath labs.”
Occlusion of the radial artery is by far the most common complication after the procedure and its occurrence precludes the use of the same radial artery for future procedures, or as a conduit for coronary artery bypass graft (CABG) surgery, Aminian explained, adding that decreasing the rate of occlusion is something that should be central in all radial programmes.
“The goal of this trial was to assess the superiority of distal radial access as compared to conventional radial access with respect to forearm radial artery occlusion,” he explained.
Through the trial, Aminian and colleagues randomised patients with an indication to PCI 1:1 to receive either distal radial access or conventional, transradial access, with both arms implementing a systemic implementation of best practices to reduce radial artery occlusion. Procedures were performed using the 6Fr Glidesheath Slender (Terumo).
Aminian document the best preventive measures for avoiding radial artery occlusion, describing these as: ”… use of slender sheaths, adequate procedural anticoagulation, a short haemostasis time with a minimum pressure strategy, [and] patent haemostasis.”
The study’s primary endpoint, incidence of forearm radial artery occlusion, was assessed by vascular ultrasound at discharge, and the trial’s key secondary endpoints included crossover rates, haemostasis time, spasm and access related complications.
Overall, 657 patients underwent conventional transradial access, and 650 patients distal radial access, Aminian detailed. Forearm radial artery occlusion did not differ between groups (0.91% vs. 0.31%; p=0.29), he revealed. “We ended up with a very low rate of radial artery occlusion in both groups, without a statistical difference,” he revealed. Of note, patent haemostasis could be achieved in as high as 94.4% of patients randomised to conventional radial access, reflecting investigator’s strict adherence to RAO preventive measures.
Some differences were noted in terms of secondary endpoints. Importantly, crossover rates were higher with distal radial access (3.5% vs. 7.4%; p=0.002), and median haemostasis time was shorter (180 vs. 153 minutes; p<0.001). Radial artery spasm occurred more with distal radial access (2.7% vs. 5.4%; p=0.015).
Commenting on these findings, Aminian said: “If you look at the key secondary endpoints, we see that distal radial access is associated with a more demanding access, [and] more crossover, which was significantly higher in the distal group, with an absolute difference of 3%.”
Looking at the procedure in terms of duration, radiation dose and contrast use, there was no impact, he commented, adding that once the access was gained there was no difference in the success of the procedure.
However, he noted that the findings did show that the haemostasis phase with distal radial access was easier, with a shorter haemostatic process and less frequent use of a selective compression device.
“This is probably one of the advantages of using the distal radial artery, that it is very superficial and you have bony basement so the haemostasis is very easy,” he commented.
During the press conference, Aminian discussed the practicality of using the distal radial approach, commenting that the technique is a “more demanding and challenging puncture, because the trajectory of the distal radial artery is less predictable than the forearm radial artery”.
Asked to elaborate on the importance of the findings by Andreas Baumbach (Queen Mary University of London, London, UK), who moderated the press conference, Aminian offered a number of key learnings from the trial.
“Although it is a negative trial, because there was no difference, we ended up with a low rate of occlusion in both groups. If you look at the haemostatic process, with distal radial, it is probably the single most effective way to avoid radial artery occlusion,” he said.
“The other thing is now we have a fair comparator. People using conventional radial access know what they have to do. If you apply good preventive measures in the conventional arm you can also end up with a low rate [of radial artery occlusion].”
But, he cautioned, this is more time consuming and requires more resources from your nurses and the staff in general.