Radial-to-Femoral Crossover Results in Minimal Delay, Has Little Impact on STEMI Outcomes

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Crossing over from radial to femoral access during primary percutaneous coronary intervention (PCI) results in minimal delays without increasing the risk of adverse events, according to a study published online July 29, 2014, ahead of print in the American Journal of Cardiology

Given the minimal impact of radial failure, operators should focus more on choosing the best access route for the patient and less on simply achieving a faster door-to-balloon time, researchers say, adding that radial access can be attempted in about 80% of STEMI patients. 

Hung Q. Ly, MD, MSc, of the University of Montreal (Montreal, Canada), and colleagues looked at 241 STEMI patients (mean age 62.2 years) undergoing primary PCI at their institution between April 2012 and March 2013. Patients were divided into 3 groups based on their final access route:
  • A priori radial access (n = 172)
  • A priori femoral access (n = 49)
  • Radial to femoral crossover (n = 20)
Reasons for crossover included inability to puncture the radial artery, failure to advance the guidewire/catheter due to severe vasospasm or tortuosity, and failure to complete PCI despite successful diagnostic catheterization. Crossover and femoral-access patients tended to be older than radially treated patients and were more likely to have hypertension and prior heart failure. Moreover, femorally treated patients had a higher degree of CAD burden, as shown by higher Syntax scores (= .002). 

Delays Not an Issue

Median vascular access-related time, defined as the delay in PCI attributed to access, was longer for crossover patients compared with other routes. The crossover group also received higher doses of radiation and tended to have longer fluoroscopy times. However, with regard to the primary endpoint of final corrected TIMI frame count, no differences were observed among the cohorts (table 1). 

Table 1. Procedural Characteristics by Access Route

Median Values

Radial Access 
 (n = 172) 

Femoral Access 
 (n = 49) 

Crossover Access 
 (n = 20) 

P Value for

Vascular Access-Related Time, mins




< .001

Time to First Device, mins




< .001

Total Procedure Time, mins




< .001

Radiation Dose, cGy*cm2





Fluoroscopy Time, mins





Final Corrected TIMI Frame Count






There were no observed differences in angiographic outcomes—final TIMI flow grade and presence of no reflow—or biochemical outcomes—peak high-sensitivity troponin T and CK-MB—among the groups.

Crossover from radial to femoral access did not increase MACE (all-cause death, reinfarction, and TVR). Rather, adverse outcomes were highest overall in the femoral group (table 2).

Table 2. In-Hospital Clinical Outcomes


Radial Access 
 (n = 172) 

Femoral Access 
 (n = 49) 

Crossover Access 
 (n = 20) 

P Value for Interaction

All-Cause Death




< .001















< .001






Major Bleeding




< .001


The only difference between the radial group and the crossover group in terms of outcomes was higher major bleeding in the latter (P = .002).

Lastly, multivariate analysis identified the following independent predictors of radial access failure: 

  • Killip Class IV (OR 3.628; 95% CI 1.098-11.981; P = .035)
  • CPR prior to arrival at cath lab (OR 3.572; 95% CI 1.028-12.407; P = .045)
  • Glomerular filtration rate, by 10-unit increments (OR 0.861; 95% CI 0.758-0.978; P = .021) 

Alleviates Fears, ‘Makes Sense Clinically’  

“Albeit higher than the data reported by large registries and clinical trials,” the 10.4% crossover rate, Dr. Ly and colleagues write, “is an encouraging result given the fact that the operators that secured [radial access] in our study were fellows with less than 2 years of cath lab experience.” This highlights the relatively fast learning curve associated with the procedure, they add, and demonstrates that outcomes “improve with increasing transradial PCI volume.” 

In a telephone interview with TCTMD, Sanjit Jolly, MD, of McMaster University (Hamilton, Canada), said the study should help alleviate the common fear of an ‘unacceptable delay’ that could result from failed radial access attempts. The 5- to 10-minute delay seen in the study “makes sense clinically,” he observed, and it “doesn't appear to portend a worse prognosis…. That being said, this is an analysis based on 20 patients crossing over, so I think we have to be cautious of that.” 

Door-to-balloon time, Dr. Jolly noted, is perceived as “probably the most important thing in primary PCI.” While it is essential from a systems perspective, he added, the focus should shift to what is best for the patient. 

“We tell our interventional fellows, ‘Don't panic. Don't rush. Do things carefully and properly, and if it takes an extra 2-3 minutes to do your primary PCI procedure, that's ok.’ It's more important to think carefully on what you're going to do and take the right approach,” Dr. Jolly said. 

In terms of study design, the center’s high rate of radial attempts is uncharacteristic of most US institutions, he continued, adding that the procedure’s prevalence will likely grow going forward. Most importantly, Dr. Jolly concluded, “operators [must] give themselves a time limit, so that if radial access clearly is not working for them, then after a set period of time they switch access sites in order to preserve timely primary PCI.”

Azzalini L, Khan R, Al-Hawwas M, et al. Effect of radial-to-femoral access crossover on adverse outcomes in primary percutaneous coronary intervention. Am J Cardiol. 2014;Epub ahead of print.

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  • Dr. Ly reports serving as a clinical research scholar for the Fonds de Recherche en Santé du Québec and receiving funds from the Montreal Heart Institute Foundation and the Des Groseillers et Bérard Chair in Interventional Cardiology from Université de Montréal.
  • Dr. Jolly reports receiving grant funding from Medtronic and speaker fees from AstraZeneca.