Main Category: Blood / Hematology
Article Date: 18 Jan 2012 - 15:00 PST
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According to a study in the January 18 issue of JAMA, patients who stop using an antiplatelet agent, such as clopidogrel, before undergoing cardiac surgery to reduce their risk of bleeding and received intravenously the platelet inhibitor cangrelor, achieved a higher rate of maintenance of platelet inhibition than those who were given placebo.
The researchers explained:
"Thienopyridines (antiplatelet agents) are among the most widely prescribed medications, but their use can be complicated by the unanticipated need for surgery. Despite increased risk of thrombosis, guidelines recommend discontinuing thienopyridines 5 to 7 days prior to surgery to minimize bleeding."
However, stopping antiplatelet treatment before operations, such as coronary artery bypass grafting (CABG) too early has been linked to higher ischemic complications. Strategies of platelet inhibition need to be defined in order to safely "bridge" patients to their surgery, with minimum risk of bleeding complications or ischemic events, according to the researchers. Cangrelor is characterized by fast, effective, predictable, and reversible platelet inhibition with fast offset of effect, desirable pharmacodynamic properties for these types of patients.
Dominick J. Angiolillo, M.D., Ph.D., of the University of Florida, Jacksonville and his team conducted a randomized, multicenter trial that included 210 individuals with acute coronary syndrome (ACS), or patients treated with a coronary stent and receiving an antiplatelet agent prior to CABG surgery, in order to analyze if cangrelor is an effective and safe medication for connecting individuals receiving antiplatelet agents to CABG surgery.
Patients discontinued antiplatelet agent use 5 to 7 days prior to surgery and were given either cangrelor or placebo for at least 48 hours, which was stopped 1 to 6 hours prior to surgery. For patients who received cangrelor the median time of infusion was 2.8 days, compared to 3.4 days for those who received placebo. The primary safety end point was excessive CABG surgery-related bleeding, while the main measure of effectiveness was platelet reactivity of less than 240 P2Y12 Reaction Units (PRUs), which was evaluated each day.
The authors found that the percentage of participants with platelet reactivity of less than 240 RPU throughout the entire infusion of the investigation drug was considerably lower in the placebo group (19.0% [16 of 84]) than the cangrelor group (98.8% [83 of 84]).
The investigators say: "The percentage of overall samples displaying platelet reactivity less than 240 PRU, patients with all samples with baseline PRU value, total patient samples that maintained higher than 60 percent platelet inhibition during study drug infusion were all greater with cangrelor than with placebo."
In total, 22 participants experienced study-defined excessive CABG surgery-related bleeding. The researchers found that excessive CABG surgery-related bleeding was not considerably different among patients who received cangrelor (11.8% [12 of 102]) or those who received placebo (10.4% [10 of 96]). For both groups, pre-CABG-surgery major-bleeding events were rare; minor bleeding events were more prevalent among participants in the cangrelor group.
The investigators conclude:
"In this trial, cangrelor achieved and maintained target levels of platelet inhibition known to be associated with a low risk of thrombotic events compared with placebo, without a significant excess in bleeding complications. Our data support the hypothesis that intravenous cangrelor is a feasible management strategy in patients waiting for cardiac surgery who require prolonged platelet P2Y12 inhibition after thienopyridine discontinuation."
Written By Grace Rattue
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today
MLA
18 Jan. 2012.
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