FDA keeps close watch on heparin dosing reports


The Food and Drug Administration (FDA) is closely monitoring reports of higher than usual doses of heparin being required to achieve activated clotting times (ACT) during cardiac procedures.

The FDA “is aware of spontaneous adverse event reports submitted to FDA’s MedWatch” and “continues to closely monitor adverse event reports for heparin,” the agency said in a statement sent to Vascular Specialist.

Clinicians started to notice difficulty in reaching optimal ACT with the widely used anticoagulant earlier this year. “Reports describing a requirement of higher than usual doses of heparin, or the opposite, of bleeding following heparin administration, are not historically unusual for this drug,” the FDA statement continued.

“FDA review of these reports is ongoing, but to date, the reporting has not had a consistent pattern suggesting deficient product quality. FDA laboratory testing of finished heparin product has been conducted when samples were provided. All samples tested to date have been within United States Pharmacopeia (USP) specification.

“FDA continues to execute a robust surveillance program for heparin—including surveillance of spontaneous adverse event reports and quality testing of imported crude heparin, active
pharmaceutical ingredient (API), and finished dosage forms—from all source countries to make sure the drugs meet quality standards.”

Since being introduced into clinical practice more than 70 years ago, unfractionated heparin has been administered during non-cardiac arterial procedures in order to prevent thromboembolic
complications. Vascular surgeons and interventional radiologists use a standardized bolus of 5,000IU of heparin during non-cardiac arterial procedures. This stands in stark contrast to cardiac interventions, where heparin is used in higher dosages.

The federal agency said clinicians who suspect product quality defects to file a report to its MedWatch program and to manufacturers.

The FDA believes that “variability in heparin response may be attributed to individual patient or healthcare system factors, and not a heparin product quality defect.”

Last year, researchers found that implementing a method of heparinization guided ACT—with a goal of 200–220 seconds—provides a “promising” increase in safety and may decrease risk of thromboembolic events while not increasing bleeding complications during vascular procedures.

Arno Wiersema, MD, a vascular surgeon in Hoorn, the Netherlands, presented the findings of the pilot ACTION trial, stating he and his colleagues “believe it is time to upgrade one of the foundations of vascular surgery to optimize patient care and to prove that ACT-guided heparinization results in far fewer thromboembolic complications.”

Speaking at Charing Cross (CX) in April last year, Wiersema said, “The success of open and endovascular arterial interventions depends on a delicate balance between coagulation and anticoagulation.”


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