GREAT NECK, N.Y., Sept. 2 (UPI) -- Conflicting studies on two blood-thinning drugs, heparin and bivalirudin, show the drugs have no clear benefit over one another when used with patients undergoing cardiac stent placement except for one thing -- their cost.
Researchers point to inconsistencies in the 14 studies that have compared the drugs because of differences in doses of heparin and the use of glycoprotein inhibitors as being part of the reason the debate of which drug is superior has become "controversial" in the medical community.
Blood thinners are used during the placement of cardiac stents, mesh-like cages inserted into narrowed arteries to restore proper blood flow, to prevent blood clots during angioplasty procedures. Some studies have shown that bivalirudin is a safer option than the longtime standard option, heparin. Bivalirudin, however, costs about 400 times more than heparin.
"Which trial to believe is controversial and not entirely clear," said Dr. Peter Berger, senior vice president for clinical research at the North Shore-LIJ Health System, in a press release. "But nearly everyone agrees that if the more expensive blood thinner is not safer or better in some way, the less expensive one ought to be used."
The most recent study on the drugs, Minimizing Adverse Hemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox, or MATRIX, is published in the New England Journal of Medicine. Researchers recruited 8,404 patients at 78 medical centers in Europe who were undergoing stent placement.
The three-trial study sought to find which drug was more effective for patient outcome, whether continuing to give bivalirudin to patients 4 to 6 hours after surgery was beneficial, and how each effected arterial access for surgeons placing stents.
The researchers reported negligible differences in the benefits of the two drugs in all three cases, although lower doses of heparin were found to be safer and effective, especially when paired with a glycoprotein inhibitor.
In an editorial by Berger that is also published in the New England Journal of Medicine alongside the MATRIX study results, he suggests studies that more evenly test the effects of the two drugs -- including more accurately measuring, and explaining, the use of glycoprotein inhibitors -- are necessary to determine whether one drug truly has benefits over the other.
"Many studies raise more questions than they answer," Berger said. "It will be interesting to see whether doctors accept the results of the MATRIX Trial or wait for more studies before deciding which blood thinner they prefer."