Study Seeking Way to Prevent Deadly Blood Clot in Stent Implanted Patients!

Every year, about 800,000 to 1 million American patients have one or more stents implanted inside their bodies to keep the artery open after it has been cleared out by angioplasty. While there is less than 1 percent has a clot form near the stent, there are still many complications, ranging from clots to strokes, heart attacks and even deaths.

In order to find out the best way to prevent potentially deadly blood clots from forming in heart patients who have artery-opening stents implanted, several competing drug and medical device makers are joining hands to start a new study, which also involves academic researchers and federal regulators, to find out how long patients should take blood-thinning medicine.

Since early this year, the trial has already been planned but the initial details were announced only on October 15, 2008 at a medical conference. The study will involve and be partly supported by the 4 United States competitors in the stent market plus 4 drug makers.

The multi-center study, which is expected to begin enrolling patients later 2008 or early 2009, will involve about 25,000 to 30,000 patients who have had one of the tiny, metal-mesh tubes implanted in a heart artery.

Most of these patients have today’s widely used drug-coated stents that will over time release a medication meant to prevent the artery from re-clogging. On the other hand, at least 5,000 of the participants will get older, bare-metal stents.

According to the investigators, patients in the study will get now-standard preventive treatment for a year after getting a stent implanted. Such treatment involves an anti-clotting drug and at least 81 mg of aspirin a day.

At the end of the one-year study, those who have no complications will be randomized, with half of them continuing on the dual blood-thinning therapy for an additional 18 months and the rest stopping it. Researchers will then determine which group had more heart attacks, strokes and deaths, as well as clots inside the stents.

Can Next-generation Heart Stent Perform Better than the Old One?

Stents are tiny metal wire-mesh tubes, with or without coated drugs. These devices can be inserted into blood vessels to keep them open so that blood flowing is ensure, and heart attack is prevented.

A new study found that patients using the so-called next-generation artery-opening device known as Xience drug-eluting stent had far fewer heart attacks and heart-related deaths after one year. The researchers from Columbia University in New York published their findings on April 22, 2008 in the Journal of the American Medical Association.

The study of 1,000 patients known as Spirit III compared results of Abbott’s Xience with Boston Scientific’s Taxus stent. It was reported that Xience proved significantly better at preventing scar tissue from re-narrowing treated blood vessels, a measure called in-segment late loss.

It also performed as well as Taxus in lowering rates of target vessel failure, a measure of re-treatment required either because the device did not work, or because of heart attacks or death. Furthermore, it also reduced major adverse cardiac events, including heart attacks and heart-related deaths by as much as 42 percent after one year.

The results of the study had no doubt convinced people that we are entering an era where we can make user of some safer and more effective drug-eluting stents.

Meanwhile, a team of researchers from Nanyang Technological University (NTU) in Singapore has been working on soluble stents for 5 years and they expect such stents can be tested on heart patients in Singapore within the next 2 years.

The soluble stents can dissolve completely over time and releases drugs or proteins to prevent side effects such as blood clots. As there is no foreign body remains in the blood vessel, it can heal much faster. This could lower the risk of the vessel becoming clogged over the next few years.

Stent-Related Blood Clot May Lead To Repeat Stent Thrombosis!

Angioplasty procedure is commonly used to clear the blockages in the coronary arteries that supply blood to the heart. Thereafter, stents, which are wire mesh tubes, will be inserted into the coronary arteries to help keep the vessels from reclogging.

The Dutch Stent Thrombosis Study indicated that one in six patients who suffer a potentially deadly clot inside a coronary stent are at a higher risk of developing another clot, especially if they had a second stent implanted during emergency treatment for the first clot.

The study was conducted by Dutch researchers from St. Antonius Hospital in Nieuwegein, the Netherlands, and its findings were presented at a joint meeting of the American College of Cardiology and the Society for Cardiovascular Angiography and Interventions in Chicago.

Clots that form inside a stent, which is known as stent thrombosis, can block the blood flow to the heart and can therefore cause a heart attack or even death. According to the researchers, using an additional stent during emergency treatment of a stent-related blood clot is a strong predictor of repeat stent thrombosis.

The study examined 437 patients with various types of stents who had stent thrombosis between January 2004 and February 2007 and found that 16.9 percent of the patients had multiple episodes of stent thrombosis: 61 patients had 2 episodes, 12 had 3 episodes and one had 4 episodes.

Meanwhile, the study also discovered that:

• Patients who had a second stent implanted during emergency treatment for their first clot were 4.2 times more likely to have another episode of stent thrombosis comparing with other patients.

• Patients who previously had a heart attack and those who developed a clot long after stent implantation (known as late stent thrombosis) were 2.6 times and 2.1 times respectively more likely to suffer a repeat episode.

Coronary Bypass Or Stents, Which One To Choose?

When a person is diagnosed with blockages in the coronary arteries, there is always a dilemma to face. Should he or she undergo bypass operation or choose the drug-eluting stents? This is certainly not an easy decision to make!

A group of researchers from the State University of New York, Rensselaer published their findings in the January 2008’s New England Journal of Medicine. In the paper, they indicated that patients with several blockages in their coronary arteries should choose to undergo bypass grafting instead of having the new generation of drug-eluting stents inserted because the mortality rates are lower.

The study compared outcomes of nearly 10,000 patients with multiple coronary lesions who were treated with drug-eluting stents and almost 7500 similar patients who underwent coronary artery bypass grafting.

After adjusting the presence of other illnesses, the chances that patients who died within 18 months were approximately 25 percent lower for those with the coronary bypass operation than those with insertion of drug-eluting stents. Estimated rates of heart attacks and need for another procedure also ranked bypass grafting higher than stenting.

The results more or less confirm that coronary artery bypass grafting remains the standard for car for patients who require clearing multiple coronary blockages. However, stents may still be an alternative for patients who are at high risk for surgical complications, or when the patient chooses a less invasive option instead.