Giovanni Amoroso (Department of Cardiology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands) is involved in developing the slender transradial interventions concept, which focuses on the maximal miniaturisation of transradial coronary interventions. He talks to Cardiovascular News about the concept and how it might help to reduce the rate of radial artery occlusion, which was recently found to be a common complication of transradial coronary interventions.1
What is the rate of radial artery occlusion after transradial intervention?
The rate varies—for example, the rate is between 5% and 10% in studies that specifically look for it. But in clinical practice, the occurrence of radial artery occlusion may be overlooked and its incidence underrated. This is because radial artery occlusion is usually asymptomatic.
What are the clinical consequences of radial artery occlusion?
Except for rare cases of patients having problems with their hands, the clinical consequences of radial artery occlusion are benign. This is because the other two arteries of the forearm—ulnar and interossea—provide enough blood supply to the hand. Therefore, most patients with radial artery occlusion will not complain of symptoms or symptoms will only be identified after a thorough investigation.
However—and this is a key issue for me—radial artery occlusion will preclude the use of the artery for subsequent interventions, which means the patient will be deprived of the many advantages of transradial approach: less bleeding, faster mobilisation, and being treated as an outpatient.
Which patients are most at risk of radial artery occlusion?
Patients with a small radial artery are most at risk; therefore in women, people with a small wrist circumference, diabetics, people of Asian descent, and elderly people, there should be a particular effort to reduce the risk of radial artery occlusion.
Acute patients are also at increased risk of radial artery occlusion as there is a tendency to apply haemostasis for a longer time in these patients because they are at increased risk of bleeding complications.
Finally, patients undergoing multiple transradial interventions have an increased risk of radial artery occlusion due to the cumulative effective of vascular trauma.
What steps can be taken to minimise the risks of radial artery occlusion?
First, use proper anticoagulation during the procedure (eg. heparin 5,000IU)—radial artery occlusion starts with a clot formation in the artery, which later evolves into scar tissue. Second, apply a “patent” haemostasis at the end of the procedure, which means try not to occlude the radial artery during compression! If that is not feasible, then apply haemostasis for as short a time as possible: two hours is usually long enough. Third—and probably most important—reduce the size of the catheters used in the procedure as much as possible. In other words, go “slender”.
What is the concept of slender transradial interventions and how can this help to minimise the risk of radial artery occlusion?
A few progressive interventional cardiologists developed the concept of the maximal miniaturisation of transradial coronary interventions (ie. slender transradial interventions) in Japan in the late 1990s. Today, there are two Slender Clubs—one based in Japan and one based in Europe—that provide interventional cardiologists with opportunities to learn this philosophy. The challenge is to downsize catheters and devices as much as possible (eg. 4Fr guiding catheters, sheathless techniques etc.) but achieve the same (or better!) procedural outcomes as those with normally sized equipment. The aim of slender transradial interventions is to minimise the risk of radial artery occlusion by both reducing vascular trauma and reduce the time for compression. An extra advantage is also a significant reduction (more than 30%) in the use of contrast dye.
What data are available for slender transradial technologies?
There are several studies that support the concept of slender technologies. For example, there are data—from Saito, Matsukage, Takeshita, and myself2—for a virtual 3Fr guiding catheter (Medikit) and data for Svelte Medical’s stent-on-a-wire system (Slender IDS, which is now also available as a drug-eluting stent). Most of these data come from large series of dedicated operators.
To help interventional cardiologists learn to use slender technologies, Slender Club Europe aims to teach techniques by mean of dedicated hands-on workshops.
If radial artery occlusion occurs, what should be done to manage it?
In most cases, radial artery occlusion will go unnoticed and will be discovered by a subsequent attempt to perform transradial intervention. In such asymptomatic cases, it is wise not to intervene. Very rarely radial artery occlusion will cause symptoms and, in these cases, percutaneous recanalisation may be considered. Once again, the best way to manage radial artery occlusion is to prevent it—and slender transradial interventions will give a great hand in that!
- Rashid et al. J Am Heart Assoc 2016. Epub.
- Amoroso et al. J Invasive Cardiol 2016; 28(3): 109–14.
For more information, see Slender Club Europe.
Giovanni Amoroso has received research grants from Medikit and Svelte Medical Systems.