Study Pinpoints Factors Related to Crossover From Radial Access

Older patient age and operator inexperience are the primary reasons for crossover from radial to femoral catheterization, according to an observational study published online May 4, 2015, ahead of print in the American Journal of Cardiology. However, crossover rates among operators with low radial volume decline as they gain experience. 

Study Pinpoints Factors Related to Crossover From Radial Access

Binita Shah, MD, MS, of New York University Langone Medical Center (New York, NY) and colleagues looked at 1,600 consecutive patients who underwent diagnostic coronary angiography with or without PCI between October 2010 and August 2013. All cases initially were attempted via a transradial approach.

Access-site crossover occurred in 166 patients (10.4%), with all changes being from radial to femoral; opposite radial artery or ulnar artery crossovers were excluded. Crossover mainly arose due to radial artery spasm, which occurred in 13.9% of patients. Neither patient sex nor whether radial access was on the right side influenced the likelihood of crossover.

Age greater than 75 years and operator experience each independently predicted site crossover. After adjustment, older age nearly doubled the risk of crossover (OR 1.90; 95% CI 1.23-2.91). Conversely, lower operator experience almost tripled the risk (OR 2.98; 95% CI 1.96-4.52). Operators with no more than 5 years spent performing radial cases were about half as likely as those with more experience to be able to cannulate the radial artery (23.4% vs 51.7%; P = .003).

Crossovers Decline With Experience

Over time, less-experienced operators also showed a decrease in access-site crossovers (P for trend < .001) that paralleled their increase in planned radial procedures. This was not the case for the more-experienced operators, who demonstrated a low and steady rate of access-site crossover over time.

“Interestingly, less-experienced operators had a low crossover rate early in the observational period,” the study authors write. “This is likely due to patient selection, given that these operators’ rate of initial [radial] approach was also very low at the start of the study and increased over time.”

According to Dr. Shah and colleagues, the rate of access-site crossover in radial PCI reported in randomized trials ranges from 0.7% to 13.8%. Additionally, 2 multicenter, international trials—RIVAL and RIFLE-STEACS—reported crossover rates of 7.0% and 9.6%, respectively, among high-volume operators.

The findings suggest that “operator experience is a modifiable factor,” the investigators observe.

Start, Finish With Radial

“There is the perception that one should choose the access site based on the patient, which is exactly the wrong approach,” Sunil V. Rao, MD, of the Duke Clinical Research Institute (Durham, NC), told TCTMD in an email. “[But] there is plenty of evidence now that one should take a ‘radial first’ approach in all patients because proficiency is so closely linked with outcomes.”

Dr. Rao noted than at his center, where more than 90% of PCI is performed radially, the femoral crossover rate is less than 3%. Although the crossover examined in the current study was strictly to the femoral artery, he said the “more reasonable approach would be to go to the other wrist or to the ulnar artery. [At our center] our algorithm is to ‘cross over’ to the left radial artery if we are having challenges with the right radial artery.”

Furthermore, Dr. Rao said 2 studies have now shown that the left radial approach is associated with higher procedural success rates compared with the right radial in patients older than 65 years and those who are no more than 5 foot 5 inches tall.

“We do about 25% left radial in our center,” he noted, adding that a “radial first” approach allows the operator to learn how to get good guide support from either radial artery.

Dr. Shah and colleagues point out that left radial catheterization “is not routinely performed due to operator physical discomfort when working from the traditional right side of the patient.”

But Dr. Rao said the best way to reduce crossovers among less-experienced operators is to “approach every case with the intent to start and finish the case from the radial artery. If you are having issues with the right radial, then ‘cross over’ to the left radial.

“You have to learn what the challenges are and use the interventional skills that you’ve developed to overcome the challenges,” he concluded. “The learning curve isn’t steep—studies indicate that it’s around 50 cases—but if you keep cherry-picking your cases, then you will end up using the radial approach in low-risk patients and not in patients who can really benefit.”

Le J, Bangalore S, Guo Y, et al. Predictors of access site crossover in patients undergoing transradial coronary angiography. Am J Cardiol. 2015;Epub ahead of print.


  • Dr. Shah reports being partially funded by an NIH grant.
  • Dr. Rao reports receiving consulting income from Terumo Medical and The Medicines Company and research funding from Bellerophon. 

Related Stories: