Compared to unfractionated heparin (UFH), the direct thrombin inhibitor bivalirudin curbs the risk of ischemic and bleeding events in patients who undergo percutaneous coronary intervention (PCI) via femoral access. However, those benefits are not seen in radially treated patients, according to a paper published online September 17, 2012, ahead of print in the American Journal of Cardiology.

Researchers led by Olivier F. Bertrand, MD, PhD, of the Quebec Heart and Lung Institute (Quebec Canada), retrospectively identified all PCI patients treated with bivalirudin at their center between April 2009 and February 2011. Out of this cohort, 125 patients were matched to 125 others who had similar baseline characteristics but received heparin during their procedure.

Compared to those given heparin, the bivalirudin-treated patients were significantly older (mean age 72 vs. 66 years; P < 0.0001), more likely to have chronic kidney disease (51% vs. 30%; P = 0.001), and more likely to receive primary PCI (30% vs. 14%; P = 0.004). However, the likelihood of being treated via radial access was the same in both groups at 71%.

Overall, in-hospital mortality was approximately 2% for each of the 2 drug treatments. Both MI and TVR rates also were similar between bivalirudin- and heparin-treated patients at 6.4% vs. 3.2% (P = 0.38) and 1.6% vs. 3.2% (P = 0.68), respectively. But when outcomes were analyzed according to access route, differences emerged. Patients only derived extra benefit from bivalirudin over heparin if treated via femoral access (table 1).

Table 1. In-Hospital Outcomes by Access and Anticoagulant

According to the authors, the findings do not rule out a possible advantage for bivalirudin over heparin in radial access. Though performed at a high-volume radial center, the small sample size and relatively short follow-up duration mean that the “observational study lacked the statistical power to provide definitive answers on hard ischemic outcomes and should be viewed primarily as hypothesis generating.”

In addition, “[b]ecause the radial approach virtually neutralizes the risk of access site bleeding, it remains possible that bivalirudin further reduces the risks of nonaccess site bleeding. Hence, the combination of radial access and bivalirudin anticoagulation could become the optimal combination for PCI,” they write. Dr. Bertrand and colleagues note that the ongoing EASY-B2B trial comparing bivalirudin vs. heparin in patients at high bleeding risk who receive transradial PCI may provide some answers.

Weighing the Cost

In addition to the efficacy of their chosen anticoagulant during PCI, a primary issue of concern for physicians interviewed by TCTMD was price.

“It’s a real question in my mind,” James Tift Mann III, MD, of Wake Heart and Vascular Associates (Raleigh, NC), told TCTMD, pointing out that bivalirudin costs approximately 100 times more than heparin. “I think that's the importance of this study. It raises the question: If you go transradially, are the potential advantages of bivalirudin worth the cost? Because there are no studies [showing] that bivalirudin reduces nonaccess site bleeding.”

In a telephone interview, Deepak L. Bhatt, MD, MPH, of Brigham and Women’s Hospital (Boston, MA), commented, “I'm quite sure that if it weren't for the issue of cost, no one would debate the findings of those clinical trials [that found bivalirudin more efficacious than heparin].” He described bivalirudin as “simply a cleaner anticoagulant with a more potent effect” than unfractionated heparin.

Dr. Mann expressed other doubts about whether bivalirudin truly trumps heparin.

"Around the world, heparin is still the anticoagulant of choice for PCI. It's only in the United States that bivalirudin is used routinely for PCI. And I think that there would have been some signals, prior to this study, if there had been a dramatic difference [in efficacy],” he said.

For Dr. Bertrand, the question of bivalirudin’s benefit is still very much open and worth additional investigation before physicians default to using the drug over heparin in clinical practice. He reported that no study to date has effectively proven that bivalirudin is preferred over heparin in radial PCI.

“If you can show that you can decrease complications and bleeding [with bivalirudin], the cost will be compensated immediately,” he said in a telephone interview with TCTMD. “The point is that [bivalirudin manufacturer] The Medicines Company should not just assume that that’s the case. They should do [further] study.”

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