Use of Smaller Catheters in Radial PCI Cuts Access-Site Complications

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Using a 4-Fr instead of a 6-Fr guiding catheter reduces the incidence of access-site-related complications in patients undergoing transradial percutaneous coronary intervention (PCI), according to trial results published April 3, 2014, ahead of print in the American Journal of Cardiology.

For the NAUSICA (Novel Angioplasty USIng Coronary Accessor) trial, researchers led by Satoshi Takeshita, MD, of Nagasaki Harbor Medical Center (Nagasaki, Japan), examined outcomes for 160 patients randomized to undergo transradial PCI with 4-Fr (n = 80) or 6-Fr (n = 80) catheters at 19 centers across Asia. The 4-Fr guiding catheter used in the study was the KIWAMI Heartrail II (Terumo; Tokyo, Japan).

There were no significant differences between the 2 groups in any baseline characteristics, including age, sex, comorbidities, and lesion types. Type A/B1 lesions were the most common in both groups (70%).

No Access-Site-Related Complications with 4-Fr

Three patients (4%) in the 4-Fr catheter group crossed over to 6-Fr catheters during the procedure. In all cases, the reason was poor support. In the 6-Fr group, 1 patient crossed over to 4-Fr due to radial spasm. Additionally, crossover from radial to femoral access occurred in 1 patient in the 4-Fr group due to failure to puncture the bilateral radial arteries and 2 patients in the 6-Fr group due to a severe radial spasm and failure of the catheter to engage.

Procedural success, procedure time, and fluoroscopy time all were similar between groups (P = NS for all). There were no deaths, Q-wave MIs, or cases of in-hospital TVR in either group. Total amount of contrast dye was about 14% less in the 4-Fr group compared with the 6-Fr group, but the difference did not reach statistical significance. Hemostasis time also was shorter in the 4-Fr group. While there was a trend toward a lower incidence of radial artery occlusion the day after the procedure (primary endpoint) in the 4-Fr group compared with the 6-Fr group, the numbers were small at 0 and 3 patients, respectively (table 1).

Table 1. Procedural Characteristics

The day after the procedure, there were no access-site-related complications in the 4-Fr group, while in the 6-Fr group, there were 5 such complications including 3 radial artery occlusions and 2 bleeds.

“The results clearly demonstrate that 4-Fr [transradial coronary intervention] significantly decreased the incidence of access-site-related complications compared with 6-Fr [transradial coronary intervention],” the study authors write. “To the best of our knowledge, this is the first [study] to document the reduced incidence of access-site-related complications after 4-Fr vs 6-Fr [transradial coronary intervention].”

They say one explanation for the failure to see a significant difference in the primary endpoint with the 4-Fr catheter may be that the sample size was based on an estimated occlusion rate of 6% in the 6-Fr group. However, the actual occlusion rate in that group was only 4%.

Additionally, although the difference in use of contrast also was not significant, Dr. Takeshita and colleagues say, “The use of a 4-Fr guiding catheter could theoretically lower contrast dye usage due to the small profile of the catheter and through the application of deep-vessel intubation.” They also point out that the shorter hemostasis times associated with the 4-Fr catheter may shorten compression times, potentially allowing patients to walk sooner and alleviating medical staff workloads. Moreover, they note, prolonged radial artery compression can be associated with radial artery occlusion and delayed reflex sympathetic dystrophy.

The study authors report that, despite the encouraging findings, 4-Fr PCI is performed in less than 1% of cases at their institution. This is due in part to difficulty in catheter manipulation and limited compatibility with other PCI devices and techniques.

Catheter Evolution Continues

“Each time you change to a different size guide there’s a different feel to those catheters,” Ian C. Gilchrist, MD, of Hershey Medical Center (Hershey, PA), told TCTMD in a telephone interview. But scaling down to smaller sizes is nothing new, he said, recalling initial concerns of some interventionalists when 7- and 6-Fr replaced 8- and 9-Fr.

“You had some people who were concerned they were too flimsy to use. What I think you’re seeing here is a continued evolution [to smaller sizes],” Dr. Gilchrist said. “The 4-Fr guides are somewhat flimsy, at least based on our standards, and they’re hard to inject contrast around without power injectors. But it’s a logical extension of what’s been going on in interventional cardiology for the last 30 years. Clearly, you’re traumatizing the artery less with [smaller guides], and that’s a positive. That’s what they are trying to show in this paper, although the study isn’t large enough to make a definitive statement.”

Additionally, Dr. Gilchrist said, the reduced risk of radial artery spasm with the 4-Fr catheters would make them “an attractive option to have available” for patients at high risk of spasm, such as young women.

Learning Curve with 4-Fr

While 4-Fr catheters are not currently available in the United States, R. Lee Jobe, MD, of Wake Heart and Vascular (Raleigh, NC), told TCTMD in a telephone interview that radialists here are already anticipating a changeover to the 4-Fr system. “Anything that we can do that can decrease the likelihood of access-site bleeding complications can only improve our procedures and outcomes,” he said.

Dr. Jobe added that although there will be a learning curve involved in switching over to the 4-Fr system, the NAUSICA results should begin to answer at least some major concerns.

“It requires a different skill set to be able to successfully maneuver [the 4-Fr catheter] in the coronaries, and lesion selection for this [type of PCI] will probably be the easier type A/B1, as we see in this study, saving the more complicated lesions for a 6-Fr approach,” he observed.

“Another important point is that as we transition to 4-Fr, which I think it is inevitable that we will, there will be less opacification of the coronaries, and we will have to make sure that visualization is adequate with the imaging equipment,” Dr. Jobe said.

Asked if it is possible to go lower than 4-Fr, he said radial catheters have likely reached a plateau “unless something changes completely in terms of stent-delivery technology.”

 

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Source:
Takeshita S, Asano H, Hata T, et al. Comparison of frequency of radial artery occlusion after 4-fr versus 6-fr transradial coronary intervention (from the NAUSICA [Novel Angioplasty USIng Coronary Accessor] trial). Am J Cardiol. 2014;Epub ahead of print.

 

 

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