Although using the radial artery as the access point for angioplasty has been linked to reduced bleeding compared to use of the femoral artery, only a small number of high-risk heart attack patients who undergo rescue angioplasty--emergency procedures following failed therapy with clot-busting drugs--are treated by radial access, according to a study published in the Journal of the American College of Cardiology: Cardiovascular Interventions.
The radial artery is located in the forearm, and the femoral artery is in the thigh. Although other studies have shown a decreased risk of bleeding with radial access, this study represents the first time bleeding outcomes were assessed for patients undergoing rescue angioplasty.
Using data from the American College of Cardiology's National Cardiovascular Data Registry CathPCI Registry, researchers examined records of 9,494 heart attack patients who underwent rescue angioplasty after failed therapy with clot-busting drugs. Also called thrombolytic therapy, these drugs are administered directly into the veins to break up blood clots quickly.
The procedures were conducted at 603 facilities between 2009 and 2013. Among the patients who received rescue angioplasty, 14 percent had their procedure performed via radial access, while 85 percent were treated with femoral access.
After adjusting for many factors, including gender, race, body mass index, high blood pressure, high cholesterol, family history of coronary heart disease, and a history of congestive heart failure, radial access was associated with significantly less bleeding. But no differences were found in mortality.
The study also found that patients chosen for radial access treatment were actually at a lower predicted risk for bleeding than those chosen for the femoral access approach, pointing to a "risk-treatment paradox." The reason for this may be due to a lack of operator comfort with the radial approach or lack of awareness of its benefits.
To determine if other factors were influencing these results, researchers used gastrointestinal bleeding, which shouldn't have differed between the groups, as a negative control. They found that patients in the radial access group had fewer gastrointestinal bleeding incidents, suggesting that unmeasured confounders, such as patient characteristics used in deciding access approach, may have influenced adjusted outcomes.
"In a large, 'real-world' registry, transradial access was used in a little more than 14 percent of patients undergoing rescue angioplasty between 2009 and 2013, with high procedural success," said Jay Giri, M.D., the study's senior author and an assistant professor in the cardiovascular medicine division at the University of Pennsylvania. Due to the lower incidence of gastrointestinal bleeding in the radial access group, Giri pointed out that the findings "also demonstrated the likely presence of treatment-selection bias regarding access site choice that cannot be easily adjusted in observational datasets. However, given the lack of research regarding bleeding avoidance in rescue angioplasty, the present study is likely to represent the best available data in this area for the foreseeable future."
"This study makes it clear that radial access is used much less than femoral. The reason seems to be that operators comfortable with femoral access are reluctant to change. The best results from radial approach are among those operators who do the majority of their cases this way. Adopting a less familiar approach safely is the challenge for many who have established good results with femoral approaches. As recently trained operators take on more of the workload this is likely to change," said Spencer B. King III, M.D., MACC, editor-in-chief of JACC: Cardiovascular Interventions.
In an accompanying editorial, Ehtisham Mahmud, M.D., FACC, director of the Sulpizio Cardiovascular Center at the University of California -- San Diego Health System in La Jolla, California, and his colleague, Mitul Patel, M.D., FACC, assistant professor of medicine at the same facility, said that because those who underwent transfemoral rescue angioplasty "were in fact at high risk of bleeding, this study indicates another failure to adequately utilize this [transradial access] very effective bleeding avoidance strategy in the highest risk patients."
They also pointed out the "surprising observation" of the relatively low mortality for rescue angioplasty patients. They attributed this to improved practice or "perhaps the relatively short period between drug therapy and rescue angioplasty." Alternatively, they suggested that excluding critically ill patients from the study may have resulted in the low mortality rate.
Mahmud and Patel said it was "puzzling" that radial access for rescue angioplasty is underutilized, noting that "the underlying reasons cannot be ascertained from the current analysis. A better understanding of the limited adoption of radial access may lead to the implementation of strategies to increase its utilization in addition to other bleeding avoidance strategies for patients at the highest risk of bleeding after angioplasty," they said.
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