Aspirin should be chosen over warfarin to prevent blood clotting in children who undergo a surgery that replumbs their hearts, according to a study led by the Murdoch Children’s Research Institute.

The research will have implications for clinicians when prescribing blood-thinning medications after Fontan surgery, a complex congenital heart disease operation redirecting blood flow from the lower body to the lungs.

The Fontan procedure is offered to children born with severe heart defects, allowing the child to live with just 1 pumping heart chamber instead of 2, according to the press release.

Chantal Attard, MD, noted that although the operation could not completely fix the heart, most were able to live well into adulthood and have relatively normal lives. However, those who have the procedure were at an increased risk for blood clots.

"Blood clots are dangerous because they can cause the heart to fail or lead to a stroke. For this reason, all patients are given blood thinning medications, with warfarin and aspirin the most common," Attard said in the press release. "Warfarin can be affected by food, other medications and illness, so patients must have regular blood tests to check their warfarin levels are safe."

The study involved 121 patients enrolled in the Australian and New-Zealand Fontan Registry. The researchers found that stroke was common regardless of which medication the patient took. Patients on warfarin, however, had poorer bone mineral density and were at a higher risk of bleeding.

Attard noted that the research showed that for patients who undergo Fontan surgery and do not have additional blood clotting risk factors, aspirin should be offered over warfarin.

Given the need for regular international normalized ratio monitoring of warfarin, a shift to aspirin would also have a cost benefit to the patient and the health care system, according to Attard.

Aspirin preferred to prevent blood clots in kids after heart surgery. EurekAlert! Published February 14, 2021. Accessed February 17, 2021.