Radial Rising: The Inevitable Revolution?

By Rick McGuire

Transradial PCI (r-PCI) seemed to be a revolution of the obvious. As the new kid on the block, it could brag that it was a safer alternative to femoral access PCI (f-PCI).

Certainly, the standard approach remained effective, but came with higher bleeding rates, as well as greater risk of hematoma, retroperitoneal bleed, pseudo-aneurysm, arteriovenous fistula. Add in the need for lengthy post-procedural supine patient immobilization and r-PCI's equivalent efficacy, and who wouldn't choose the alternative? Especially one allowing patients to sit up immediately, often go home the same day, and then monitor themselves for access site bleeding, applying compresses if necessary with their free hand. And, it turns out, it's cheaper too.

A no-brainer for sure.... But, while US penetration is up (finally), it still lags compared to many countries. The SWEDEHEART registry showed a swift uptake for r-PCI in Sweden to 67% of all PCIs in 2011, up from 14% in 2003. Registries in the UK demonstrated an uptake of 50.8% in 2010, up from 17.2% in 2006, and the Canadian r-PCI rate is about the same. According to the National Cardiovascular Data Registry® (NCDR), the proportion of r-PCI procedures in the United States went from 1.2% in the first quarter of 2007 to an anemic 16.1% in the third quarter of 2012.1 This analysis of the NCDR's CathPCI Registry® included 2,820,874 procedures at 1,381 sites. Among these sites, about 13% (180/1,381) performed no r-PCIs, however, and only 2% (22/1,381) performed r-PCIs more than half the time. The rate was slowest in the East South Central United States region, coming in at below 4%.

So, r-PCI now accounts for one of every six PCIs performed in contemporary clinical practice, but the lag in uptake continues in specific patient subgroups, notably higher-risk patients: those ≥75 years, women, and patients with acute coronary syndromes (ACS; both with non-ST elevation and STEMI).

A New Gold Standard?

Still, a tipping point seems to have been reached in the United States, and the direction is unmistakably towards more rapid adoption. Fueling the momentum: several fresh analyses piling up evidence pointing to clear superiority for r-PCI across a range of critical measures.

In the July 2013 JACC Cardiovascular Interventions, Mamas et al. found a highly significant 29% reduction in 30-day mortality in 46,128 STEMI patients using the radial access site, a huge benefit that comes with no additional cost.2 Also in JACC Cardiovascular Interventions, published online before print, investigators at the University of Iowa Hospitals and Clinics, Iowa City, performed a meta-analysis of 12 studies conducted at centers experienced in both approaches, including 5,055 patients.3 Death and major bleeding, the primary outcomes, were significantly reduced with r-PCI: mortality 2.7% versus 4.7% (OR = 0.55; 95% CI 0.40-0.76; p < 0.001) and major bleeding 1.4% versus 2.9% (OR = 0.51; 95% CI 0.31-0.85; p = 0.01).

The relative risk of access site bleeding was lower with r-PCI, (2.1% vs. 5.6%; p < 0.001), while stroke risk was similar for both approaches at 0.5%. Procedure time was slightly longer in the radial group compared to the femoral group (mean difference 1.52 minutes; 95% CI 0.33-2.70; p = 0.01). Crossover was more frequent in the radial group (4.6%) than with the femoral group (1.1%).

In the discussion, Karrowni et al. underscored that while timely reperfusion is critical in STEMI,3 the procedural delay of a minute and a half for r-PCI with experienced operators "may not be a significant concern." The lower bleeding rates with r-PCI take on particular value in STEMI patients, given that the emergent nature of the procedure is likely to be accompanied by aggressive antiplatelet and antithrombotic therapies. Thus, by minimizing the "penalty" of increased bleeding, r-PCI may allow higher doses of anticoagulants, potentially leading to greater ischemic reduction. Also, the authors added that due to the radial artery's superficial course, access site bleeding can be quickly recognized and treated via compression, allowing safe and rapid hemostasis.

On the other hand—well, leg—femoral PCI more readily facilitates central venous access and the insertion of hemodynamic assist devices in unstable patients.

Dmitri V. Baklanov, MD, and colleagues reviewed NCDR CathPCI Registry data from 2007-11.4 In 294,769 patients undergoing PCI for STEMI at 1,204 hospitals, procedural success rates were similar. In this analysis, r-PCI was associated with 4-minute longer median door-to-balloon time (78 vs. 74 min) with fluoroscopy time extended by 2.4 minutes (p < 0.001). However, r-PCI lowered contrast volume (180.0 mL vs. 185.0 mL; p < 0.0001).

Again, r-PCI reduced both adjusted bleeding risk (OR = 0.62; 95% CI 0.53-0.72; p < 0.0001) and adjusted in-hospital mortality risk (OR = 0.76; 95% CI 0.57-0.99; p < 0.0455). The authors, while concluding that a wider adoption of r-PCI for STEMI might significantly improve outcomes, called for confirmation through an adequately powered prospective randomized trial.

Testing the hypothesis that the safety associated with r-PCI may translate into a survival benefit in higher-risk patients, Shamir R. Mehta, MD, McMaster University, Hamilton Health Sciences in Ontario, et al. compared efficacy and bleeding outcomes in RIVAL (RadIal Vs femorAL access for coronary intervention trial), stratifying 7,021 patients by both access strategy and STEMI/NSTE-ACS status (n = 1,958/5,063).5

Operator radial experience was greater in STEMI versus NSTE-ACS patients (400 vs. 326 cases/year). Among STEMI patients, the primary outcome of death/MI/stroke/non-CABG-related major bleeding at 30 days was reduced with r-PCI (3.1% vs. 5.2%; HR = 0.60; p < 0.026). For NSTE-ACS, the rates were similar at 3.8% and 3.5%, respectively (p < 0.49). All-cause mortality was lower for r-PCI at 1.3% as compared with 3.2% for f-PCI (HR = 0.39; p = 0.006). Similarly, in primary PCI, r-PCI mortality rates improved over those seen with f-PCI (1.4% vs. 3.1%; HR = 0.46; p < 0.041). The authors concluded that when the operator has considerable radial experience, the radial approach may be preferred in STEMI patients.

An accompanying commentary to the Mamas paper by Carlo Di Mario, MD, PhD, and Gioel Secco, MD, refers to r-PCI as "the gold standard treatment for STEMI patients."6 They wrote, "Young trainees must be trained in radial angioplasty and STEMI treatment using radial angioplasty, and these numbers should be separately collected. Mature operators should feel a moral obligation in learning new basic skills that will increase their performance."

Revolutionary Costs

Do the reductions in access-site complications actually reduce costs? Amit P. Amin, MD, at Washington University School of Medicine, St. Louis, Missouri, and colleagues identified patients at five US centers undergoing 7,121 PCI procedures performed from January 1, 2010 to March 31, 2011.7 They analyzed costs on the day of PCI through hospital discharge. In their analysis, r-PCI accounted for 17% (1,219) of the PCI procedures and was associated with a half-day shorter length of stay (2.5 vs. 3.0 days) and fewer bleeding events (1.1% vs. 2.4%).

The data indicated that r-PCI patients were younger and less likely to undergo primary PCI for STEMI. Also, they had fewer risk factors and comorbidities such as hypertension, peripheral vascular disease, and prior heart failure, and had higher glomerular filtration rates. Total unadjusted costs were $1,541 lower in the r-PCI group than in the f-PCI group. After risk adjustment, the total cost savings for r-PCI was $830; a significant proportion of those savings were in the post-procedural period (procedural = $130 vs. post-procedural = $705).

Stratifying patients, using the NCDR CathPCI model, according to bleeding risk, Amin et al. found savings were greater in patients at higher bleeding risk. Length of stay was a day shorter in the high-risk group (CI 0.18-1.79; p = 0.017). Same-day discharge rates were 4.4% and 2.8% for r-PCI and f-PCI groups, respectively (p = 0.001). The authors wrote, "As hospitals increasingly use same-day discharge protocols for [r-PCI] patients, length of stay will expectedly decrease, and greater cost savings attributable to [r-PCI] will likely increase further."

Dmitriy Feldman, MD, assistant professor of medicine at Weill Cornell Medical College in New York, told CSWN: Interventions that most PCI patients are kept overnight for observation at his institution. "That practice was developed mainly for femoral procedures. Now, however, we're in the process of reevaluating and modifying it." He noted also that while RIVAL showed that 7% of cases initiated through radial access need to be completed via femoral access because of difficulty initiating the procedure, among patients in whom radial vascular access is achieved, procedural success rates are as high as with femoral access.

Power to the People... or Not if Not Offered

One blaring feature these analyses share: they show that the patients least likely to be treated via radial access in the United States are those patients most likely to benefit from r-PCI: patients aged ≥75 years, women, and ACS patients.

What accounts for this counterintuitive finding? Dr. Feldman suggested that the preponderance of femoral access training in the U.S. has not been mirrored in Europe, even going back to the early days of angioplasty. Also, he said, the learning curve for individual r-PCI practitioners naturally inclines them to first get comfortable treating patients with stable coronary disease and favorable anatomy before moving on stepwise to higher-risk situations (such as older patients and those with ACS). Concern over door-to-balloon time in STEMI patients may play a role as well in avoiding r-PCI in more challenging cases.

But why would Europe and Canada continue to have a better supply of practitioners with sufficient experience to confidently treat higher-risk patients? Sanjit Jolly, MD, associate professor of medicine at McMaster University, Hamilton Health Sciences, Hamilton, Ontario, Canada, offers one likely explanation: lower average operator volume in the United States than in Canada or Europe make it harder for US interventionalists to get the number of cases they need to develop proficiency.

"There are fewer interventional cardiologists per capita in many parts of the world compared to the United States—and fewer cath labs. As a result, in those other countries, most of which have government-run national or regional health services, each center does more procedures on an annual basis than US centers. The governments control the number of centers to achieve high-volume efficiencies. I think that is the predominant reason," said Dr. Jolly.

How many cases is that? "That's a key question. Is it 50 or 100 or 250? And while 75 per year are needed to retain skills for femoral, is it higher for radial? We have data from RIVAL showing that those with higher volumes have better outcomes, but we don't know the answers to these specific questions yet."

Playing catch-up will likely speed up in the United States, given the class IIa recommendations in the guidelines, Dr. Jolly noted. "One of the big drivers in certain US regions is that referring physicians are sending patients preferentially to those centers offering radial access. That is a very strong motivator for competing centers."

An additional motivation comes from radial access supporting fast in-fast out. Although there is no official figure, the proportion of r-PCI patients discharged on the day of their procedure appears to be very high, with Dr. Jolly estimating its use at greater than 50% at his center.

Might we see the tide turn in the other direction, with trainees becoming so entrenched with radial access that they lack sufficient training in femoral access? Dr. Jolly noted interventionalists should be comfortable with both techniques: "We will always need backup femoral."


1. Feldman D, et al. Circulation. 2013;127:2295-306.
2. Mamas MA, et al. JACC Cardiovasc Interv. 2013;6:698-706.
3. Karrowni W, et al. JACC Cardiovasc Interv. 2013 July .[Epub ahead of print]
4. Baklanov DV, et al. J Am Coll Cardiol. 2013;61:420-6.
5. Mehta SR, et al. J Am Coll Cardiol. 2012;60:2490-9.
6. Di Mario C, Secco G. JACC Cardiovasc Interv. 2013;6:707-8.
7. Amin AP, et al. JACC Cardiovasc Interv. 2013 July. [Epub ahead of print]

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