Interventionalists Survey New Blood-Thinning Options

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 - blood thinning

Bivalirudin’s positive showing in HORIZONS AMI portends a shift in the therapeutic regimen for STEMI patients undergoing PCI.

The choice of anticoagulation therapy for STEMI patients undergoing PCI has remained unchanged for decades; yet several recent studies, especially last year’s HORIZONS AMI trial, have presented new considerations for interventionalists and administrators when considering the agents to use during stenting these at-risk patients.

For years, the only option available in the cath lab has been unfractionated heparin (UFH), accompanied by glycoprotein (GP) IIb/IIIa inhibitors—which as of May 2008 was still being used in 90 percent of patients undergoing PCI. The risk of hemorrhagic complications and thrombocytopenia, however, has caused investigators and clinicians to seek alternative anticoagulation therapies. A confounding factor to those who seek a standardized regimen is the imprecise nature of the current guidelines. The need to have a standard, accepted therapy is especially important in the current economic crunch, as administrators do not want to overstock their shelves with an abundance of drugs.

The comfort level physicians have utilizing the current strategy of UFH and GP IIb/IIIa inhibitors might be difficult to assuage. It’s becoming clearer, though, that “the more we understand about UFH, the more we don’t understand it,” says Gordon Vanscoy, PharmD, MBA, associate dean at the University of Pittsburgh School of Pharmacy. “Unfortunately, a very crude agent is still the standard of care.” That may change as the antithrombotic agent bivalirudin (Angiomax, Medicines Company) makes inroads in STEMI care.

A three-year project called RACE (Reperfusion of Acute MI in North Carolina Emergency departments) is designed to help standardize STEMI protocols. It involves caregivers at 65 hospitals and associated emergency medical teams throughout North Carolina. All 21 centers that perform primary PCI for STEMI patients are involved in the project, according to Christopher Granger, MD, a cardiologist at Duke University Medical Center in Durham and lead investigator of RACE.

The standardized approach for RACE is based on the current ACC/AHA guidelines, which do not reflect the positive results for bivalirudin in the HORIZONS AMI trial. In HORIZONS AMI, patients who received bivalirudin had significantly lower rates of major bleeding, all-cause death and death from cardiac causes after one year, compared to the standard drug therapy of UFH and GP IIb/IIIa inhibitors.

The current guidelines do recommend bivalirudin for patients with a history of heparin-induced thrombocytopenia (HIT) and as an “alternative agent” for patients with no history of HIT. Vanscoy suggests, based on HORIZONS AMI data, that the use of bivalirudin may confer both an economic and clinical advantage. Data on bivalirudin are still being analyzed, but the current information indicates that the drug works well with many subgroups, which Vanscoy attributes to the agent’s short half-life (average 25 minutes compared to 1.5 hours for UFH).

The Minneapolis Heart Institute has implemented a standardized anticoagulant protocol for the rapid transfer of STEMI patients. The Level One network involves 35 hospitals across a stretch of 210 miles. Each hospital administers 600 mg of clopidogrel (Plavix, Bristol-Myers Squibb), aspirin and an IV bolus of heparin. This type of standardization is gaining popularity, as it reduces errors and confusion, says Timothy Henry, MD, director of research at the Minneapolis Heart Institute and an interventional cardiologist at Abbott Northwestern Hospital in Minneapolis.

Columbia University Medical Center in New York City has acute coronary syndrome committees comprised of physicians, ER doctors and cardiologists who determine treatment for chest pain patients, according to Gregg Stone, MD, director of cardiovascular research and education at Columbia and principal investigator of HORIZONS AMI. Nearly all STEMI patients at Columbia are treated with a mechanical reperfusion strategy, then “the interventional cardiologist’s opinion will dominate in the cath lab,” Stone says. Currently, all ?STEMI primary PCI patients who present at Columbia receive four baby aspirin, 600 mg clopidogrel, beta blockers in the absence of contraindications and, since HORIZONS AMI, bivalirudin alone. Prior to HORIZONS AMI, patients received UFH and GP IIb/IIIa inhibitors.

At Duke, most STEMI patients undergoing primary PCI receive