Transradial cardiac catheterization—accessing the coronary arteries via the radial artery in the wrist, instead of through the femoral artery in the groin—has been a popular procedure in many parts of Europe and Asia for decades. Currently the majority of cardiac catheterizations performed in the United Kingdom, France, Scandinavia and many other countries around the world are done transradially.
Although the procedure is less common in the United States, with around 20 percent of catheterizations per- formed using the radial artery, more and more physicians are becoming enthusiastic practitioners. And MedStar cardiac interventionalists are helping to lead the charge, according to John Wang, MD, chief of the Cardiac Catheterization Lab at MedStar Union Memorial Hospital.
Dr. Wang performs nearly a thousand cardiac catheterizations per year, 90 percent of them transradially. He says the benefits of the procedure are clear and compelling. “Transradial catheterization is safe and cost-effective,” Dr. Wang says. “There is virtually no post-procedure bleeding, and the risk of major vascular complications is almost zero. That means fewer additional tests, treatments or hospital stays.”
But perhaps the most important benefit, he continues, is the enormous increase in patient satisfaction using the transradial method when compared to traditional femoral- artery catheterization. “There is a dramatic improvement in comfort, convenience and recovery time for patients. Immediately after a transradial procedure, patients can sit up, move around, get a drink, go to the bathroom— and then 90 minutes later they are headed home,” says Dr. Wang.
In contrast, after catheterization performed via the femoral artery, patients must lie flat for six to eight hours to avoid the risk of significant bleeding and other complications. This supine position may be especially uncomfortable for those who have back issues, congestive heart failure or respiratory problems.
After a quick, non-invasive test in the catheterization lab to ensure sufficient collateral blood flow to the hand, the physician inserts a small, hydrophilic-coated sheath that slides easily into the radial artery. A guidewire is advanced from the radial artery to the ascending aorta, and a tiny catheter is advanced over the wire. Checking for arterial blockages takes just a few minutes, and if the patient’s condition indicates a need for angioplasty or a stent, that can be done through the wrist as well. About a third of transradial catheterizations progress to angioplasty or stent procedures.
New technologies have made the procedure even more effective. One major innovation of the last decade has been the transradial (TR) band, an inexpensive wristband that resembles a watch and uses a Velcro strap. The TR band contains an air diaphragm that can be inflated to put gentle pressure on the access site after a radial procedure. Smaller catheters and more easily steerable wires also have made it easier to maneuver via the small blood vessels in the wrist.
The most likely complication of transradial catheterization is radial artery spasm, which can cause discomfort for the patient and make manipulating the catheter difficult for the physician. Spasms can be reduced by:
smooth and steady catheter insertion by an expert practitioner
hydrophilic coatings on IVs and sheaths
anti-spasmodic drugs, such as nicardipine
blood vessel dilators, such as nitroglycerine
Radial artery occlusion is another occasional complication and is less likely to occur with the newer, smaller sheaths and catheters and with the use of an appropriately dosed anticoagulation agent, such as heparin. In a small percentage of cases, variations in the wrist artery anatomy, the need for larger catheters in complex procedures, or chronic conditions including renal failure can make femoral access a better option for some patients.
Even with these few potential issues, the success rate for the transradial procedure, according to national statistics, is greater than 90 percent, says Robert Lager, MD, an interventional cardiologist at MedStar Washington Hospital Center. Dr. Lager, who performs more than 80 percent of his cases transradially, says some physicians may be less likely to embrace this approach because of a steep learn- ing curve. He and his partner, Robert Gallino, MD, proctor national courses for both practicing interventional cardiologists and cardiology fellows in the transradial method, covering fundamentals, fine-tuning techniques for practitioners and providing information about various options for technologies, such as catheter selection.
“As more cardiology fellowship programs train new doctors to use the transradial approach, we are getting closer to a tipping point of transradial becoming the default for cardiac catheterization,” says Dr. Lager. “Patients are already seeking out physicians who will do this procedure, and the demand is only going to increase.”
Patient demand has prompted the construction of a new radial lounge now in development at Union Memorial. Cheryl Lunnen, vice-president of MedStar Heart & Vascular Institute for the Baltimore region, says, “Instead of having a clinical look with individual bays, the radial lounge will be a large open space with recliners—more relaxing for patients, and easier to navigate for caregivers.” Because those caregivers are able to monitor several patients post- procedure, staffing needs are lower than after traditional femoral catheterization—another cost-efficient measure.
Says Dr. Wang, “I tell my patients that this procedure is easier than going to the dentist—and it’s also a less invasive option that provides better outcomes for them.”
Robert Lager, MD, demonstrates a recent transradial catheterization procedure.
Dr. Lager inserts a short needle into the radial artery.
A guidewire is advanced into the needle and is exchanged for a short sheath.
A specially formed catheter is advanced into the sheath and into the ascending aorta.
A coronary angiogram is performed with the catheter engaged in the heart artery.
An inflatable compression band around the wrist puts gentle pressure on the access site at the conclusion of the case.