Health

Viagra may limit clot formation after a stent placement surgery

The surgical placement of stents to prevent heart attacks is quite common, but sometimes it may cause thrombosis or narrowing of the arteries. A new study suggests that a popular drug for erectile dysfunction can reduce the risk of these complications.

Stents are small metal mesh tubules that are placed in the damaged arteries to keep them open and to facilitate blood flow. According to the American Heart Association, their use is quite common.

In some patients the stents reduce the risk of stenosis, but others may have the opposite effect as the tissue that grows rapidly around the metal mesh can lead to clot formation and narrowing of the arteries. This is particularly the case when using non-drug stents to prevent thrombosis and vascular stenosis.

Despite the use of drug-coated stents, the risk of clots still exists. A new preliminary study conducted by the Seoul National University Hospital in South Korea found that drugs used to treat erectile dysfunction can effectively prevent thrombus formation.

Sildenafil used to treat erectile dysfunction – the known viagra – originally developed as an antihypertensive, and is now marketed under the brand name Revatio for the treatment of arterial pulmonary hypertension. The drug can increase blood flow and relax the arteries, thus achieving more free circulation of blood in the vessels.

The new study revealed that sildenafil reduced platelet aggregation by 30%. Platelets are the reason why bleeding stops after any injury. These are cells that detect the damage in a vessel and are directed there to form a thrombus. Therefore, people who have thrombus arteries are prescribed medications that lower platelet levels to reduce the risk of heart attack or stroke.

In the present study the researchers found that sildenafil increases the activity of an enzyme called protein kinase G (PKG). PKG prevents thickening of the artery walls after an operation and helps to avoid complications.

The authors of the study explain that stent placement reduces PKG activity and leads to thickening of the arteries and increased platelet aggregation. For this reason activation of PKG is very important for the mechanism by which sildenafil can prevent the artery stenosis again.

The drawback of the study is that it was conducted only in animals. If the clinical trials show similar results, the drug may be administered immediately as it is already tested for other purposes. Researchers argue that sildenafil may be the ideal drug either for lining stents or for oral ingestion after surgery.