SCAI: Advice for beginning radialists
PHILADELPHIA--Beginning transradialists would be wise to choose easy cases, such as younger, taller men and diagnostic-only patients, with the ultimate goal of mastering the full range of patients, according to Jennifer Tremmel, MD, who spoke at the Transradial Interventional Program (TRIP), which was hosted by the Society for Cardiovascular Angiography and Interventions (SCAI) on Jan. 15.

Tremmel, director of transradial interventions at Stanford University Medical Center in Stanford, Calif., said that most experienced radialists will claim that everyone is a good candidate for transradial access until proven otherwise. However, there are certain patients to avoid in the beginning of one's radial career.

Dialysis patients with AV fistulas:
"Overall, it's hard to say there is any absolute contraindication, but in these patients we shouldn't perform radial access."

Failed Allen's test: "Many people would say these patients would be an absolute contraindication, although we have European colleagues, for example, who would disagree."

Hemodynamically unstable patients: Particularly with low blood pressure.

Patients with CABG conduits: "If your surgeons like radial artery conduits, they may not want interventionalists using the radial access. However, the data are conflicting about this. Some data suggest there is harm done to the radial artery and the endothelium during the transradial approach, but there are data to suggest we don't and that these arteries can still be used as conduits."

Patients with Reynaud's disease: "It depends on the severity of the disease and the level of treatment."

Large bore procedures: "Avoid performing radial access in patients whose procedure will utilize a large bore wire, such as 8F or bigger, or 7F in women, although there is increasing use of sheathless procedures, so you can perform an 8F sheathless procedure and take your size down to a virtual 6F."

Any patient with a poor pulse: "Especially in patients that have had many procedures and in cardiac transplant patients who may have had so many artery lines that the radial artery is absent and instead replaced by collaterals."

Predictors of Failure

Some predictors of failure in low- to intermediate-volume operators include:
  • Older patients, greater than 75 years;
  • Patients with prior CABG;
  • Shorter patients; and
  • Women.

"Interestingly, patients that we find more challenging are ultimately the ones who are most likely to benefit from having a transradial procedure—women; those with low body mass index (BMI); elderly patients, who often tend to be small women; and STEMI patients.

The biggest sex difference in the cath lab is women, who have two- to three-times more bleeding and vascular complications compared to men, Tremmel said. Women predominantly comprise the group who has retroperitoneal bleeds, especially small women. "Radial access has a pronounced effect in women. Men have a reduction in their bleeding complications as well, but women benefit even more."

The issue of BMI is interesting, she said, referencing the "obesity paradox." There are many vascular complications in those who are morbidly obese, with a BMI greater than 40. But the group with the highest rate of complications are the those with a BMI less than 18.5. Those in the middle of the spectrum have the lowest rate of complications. "Concentrating on the group with low BMIs will ultimately produce more benefits."

STEMI patients have a high risk of bleeding and will benefit more from a radial approach. "It's not necessarily more difficult to perform the radial access in these patients, but you need to be adept at doing radials quickly," she said.

Data have emerged attesting to the bleeding reductions in STEMI patients when the radial access is used. Also, it's been found that the use of the femoral approach is the most important predictor of major bleeding. "This group will be the last one you want to tackle. But once you can do these, you can do anything."

Another group that will benefit from the radial approach are anticoagulated patients. "We know these patients can be safely done, those with a mean INR of 2.2 with a range of 1.4 to 3.4."

"Start with easier cases, but aim to be nonselective," Tremmel concluded. "Start with larger men and gradually introduce small women, more complex cases and more urgent cases. Your confidence and skill will increase the more radial procedures you perform."