John C. Messenger, MD, FSCAI

This is an excellent study and it’s commendable that one center could do it on their own. One of the big reasons for an investigation of this concept is that many of the centers that have adopted radial artery access but don’t have a lot of experience with it have high rate of radial artery occlusion, somewhere between 3% and 5%, if there is inattention to detail in the procedural aspects and postprocedural hemostasis. The concept of using distal artery access is very important to investigate to see whether it is safe, feasible and applicable to a lot of patients. Those are the things that this study set out to see and was effective in conquering.

Patient selection is important for distal radial artery access. Use of preprocedural physical exam and ultrasound screening is an important key to take home from this study. It wasn't an all-comers trial where you just went in and tried to get access. There was a fair amount of screening upfront to determine whether patients were suitable candidates first and foremost. Importantly, there was a significant proportion of patients that didn't have suitable distal radial artery anatomy that was sizable enough to allow for access. That said, it gets to patient selection using ultrasound, which is really how we do this. There are many sites that still don't do radial access with ultrasound. It highlights the key best practice of ultrasound access for both radial and femoral, no matter how you're doing it, and it's critically important for distal radial access.

One of the important findings of DIPRA is that distal access is safe to do; it doesn't have any sequelae in terms of hand function; there were no major bleeding complications; and the crossover rate was very low. If you can accomplish distal access with excellent technique using ultrasound, it's just as good as proximal.

The study also appears to confirm that there's no radial artery occlusion with distal access, which is a key finding.

The learning curve for [distal access] will be present. I think the big differences are both the procedural aspects of the setup of the table and how you position the hand. Doing left radial access from the right side of the table ergonomically works well and it's pretty easy to do. The use of hemostatic devices by your nursing staff also is a learning curve. These are devices that do require some attention to postprocedural care. Making sure that people are comfortable using these prespecified distal radial artery occlusion devices, or hemostatic devices, is really going to be important.

These findings are a fantastic movement forward. There have been lots of case reports on this and lots of discussion, but no one had been willing to do a large-scale randomized trial. It's great that the investigators at Baylor Scott and White Health were able to do this.

Sunil V. Rao, MD, FSCAI, FACC

There’s been a lot of interest in the use of the distal radial artery for both CV angiography and intervention. The theoretical benefits of the distal radial approach compared with the proximal radial approach is potentially a lower risk for radial artery occlusion; however, it may be harder to access the distal radial artery. In addition, we really don’t know much about hand function in patients who undergo distal radial access compared with proximal radial access.

By way of background, we do have some data comparing hand function between radial access and femoral access. It turns out that hand function can be affected by a lot of different things, not just vascular access. In the studies that have compared hand function between the radial approach and the femoral approach, there really has been no significant difference. In fact, there were some patients who underwent femoral access and did have some impairment of hand function, suggesting that it may be a residual effect of sedation during the procedure.

The bottom line was that there were no significant differences between the distal and proximal radial artery approaches with respect to the QuickDASH questionnaire, hand grip strength or pinching strength, suggesting that there really is no fear about hand dysfunction when using the distal radial access approach.

These patients are going to be followed long term, so we’ll be curious to know if there’s going to be any change in those particular parameters over time.

The DIPRA study gives us a lot of reassurance for those of us that are doing distal radial access. Not only can we potentially reduce radial artery occlusion, but we’re not putting the patient at any risk for hand dysfunction as well.