Viagra Coated Stent Reduces Blood Clots, Prevents Narrowing of Coronary Arteries

A preliminary research has found that stents coated with an erectile dysfunction drug may help prevent arteries from becoming narrow or blocked again.

What are Stents?

Atherosclerosis, also known as blocked coronary arteries, is the build-up of fatty deposits called plaques on the inner walls of the arteries. These plaques can affect the blood flow to the heart muscle, leading to heart diseases. A stent is a metal mesh that opens a blocked artery and reduces the risk of a heart attack Angioplasty and stenting are performed to widen the blocked artery. Some stents are bare metal, and some are coated with medications (drug-eluting stents) to help keep the artery open. Stenting may involve some risks. Traditionally used bare metal stents can lead to excessive tissue growth within the treated portion of the artery, causing restenosis, whereby the artery becomes narrow or blocked again.

Drug-eluting stents coated with medications can help prevent restenosis. However, these drug-eluting stents may lead to the development of a blood clot near the stent soon after the placement procedure. To prevent the formation of blood clot, patients are routinely prescribed aspirin and other anti-platelet medications.

To overcome these complications after stenting, a research team at the National University Hospital, Seoul, conducted a series of studies. They conducted research into the role of the commonly used erectile dysfunction drug, sildenafil, in reducing both restenosis and blood clot formation.

Initially, sildenafil was developed as a medication for treating high blood pressure. However, its side effect was revealed to be the improvement of erectile dysfunction. Sildenafil is sold under the brand name Viagra.

Sildenafil in Preventing Restenosis

The research team tested the effect of sildenafil in rats. The findings showed that

• Sildenafil drug was effective in reducing the clumping of blood platelets by 30%
• The drug increased the activity of an enzyme, protein kinase G (PKG), which helps prevent the thickening of artery walls when given after injury to the artery
• Stent implantation can reduce PKG activity, increase the thickening of artery walls, as well as the clumping of platelets. But the drug sildenafil activates the PKG pathway, which prevents restenosis

The findings suggest that sildenafil could be used for coating drug-eluting stents. Sildenafil could also be prescribed orally to prevent restenosis following stent implantation.

“The enzyme PKG is highly expressed in arteries as well as in the erectile tissue of the penis, and sildenafil works in both,” said lead study author Dr Han-Mo Yang, an associate professor in the division of cardiology at Seoul National University Hospital.

"Our study is limited by involving only animals. If clinical trials show that sildenafil reduces restenosis after stent placement, it could be used in the clinical setting right away because the drug is already used in the real world for other purposes," said Yang.

The preliminary research is presented at the American Heart Association's Basic Cardiovascular Sciences 2017 Scientific Sessions.

Reference:

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Source-Medindia