This study compared the effect of two different types of blood thinners, aspirin and anticoagulants, after valve replacement surgery. 

As blood flows through and out of the heart, it needs to flow through heart valves. Heart valves separate each of the heart compartments and stop the blood from flowing backwards. When a heart valve is damaged, the valve can be replaced using a prosthetic. Heart valve prosthetics can either be mechanical (made of man-made materials) or biological (made of human or animal tissue). After surgery, patients are at risk of developing blood clots and need to take blood thinners. For mechanical prosthetics, blood thinners are required for life, while biological prosthetics (bioprosthetics) require only short-term blood thinning (approx. 3 months) after surgery.

This study compared the effects of the use of two blood-thinning treatments after bioprosthetic heart valve surgery of the aortic valve. The aortic valve helps to pump blood from the heart to the rest of the body and is the most common valve that requires replacement. 

The study collected data from 1,118 patients that underwent aortic valve replacement and received postoperative blood thinning treatment for up to 6 months across Europe, Canada and India. Patients either had aortic valve replacement alone, or in combination with coronary artery bypass surgery. The study focused on two treatments: anticoagulants (vitamin K inhibitors; for example warfarin) and the antiplatelet aspirin. Both treatments prevent blood clot formation by inhibiting different parts of the clot formation pathway.

The study found that patients who received anticoagulants had a higher risk of developing complications such as coronary artery disease and kidney damage. 2.8% of patients on anticoagulants suffered from thromboembolism (clot formation) compared to 1.5% treated with the antiplatelet aspirin. Furthermore, patients on anticoagulants were more likely to suffer from major bleeding (3.6%) compared to aspirin (1.3%).

Compared with aspirin, treatment with anticoagulants was associated with more health complications within 6 months after bioprosthetic aortic valve replacement surgery, suggesting that aspirin is the preferred treatment. 

In addition to anticoagulant and aspirin treatment, another blood thinner, heparin, was also given to a large amount of patients, which is likely to obscure the results.  

If you or someone you know is interested in undergoing valve replacement surgery, ask a doctor the different post-operative blood thinning treatments that are available to help reduce the chances of complications.