When a patient feels chest pain upon exertion or has a heart attack, a clot or narrowing of the coronary arteries is usually the culprit. Cardiac stents are small expandable tubes that interventional cardiologists place in the heart’s arteries to open blockages and restore needed blood flow. However, all stents are not created equal, nor are they a perfect fix, so clinicians continue to seek a device that provides the maximum effectiveness with the least amount of risk.
Historically, the main drawback of simpler bare metal stents is their increased formation of scar tissue inside the stent, compared to newer drug-coated stents. However, drug-eluting stents typically require a longer course of anti-clotting agents, which puts patients at risk of a bleeding event. University of Vermont Professor of Medicine Matthew Watkins, M.D., was part of a team of international investigators who led a multicenter trial to evaluate the effectiveness of a new platinum chromium bare metal stent in higher risk patients with coronary artery disease.
“This trial involved reexamining an older technology, changing it, and determining if it can work better,” says Watkins.
One of the group’s coordinating principle investigators – John Wang, M.D., of Union Memorial Hospital in Baltimore, Md. – presented the nine-month clinical outcomes from the trial at the Cardiovascular Research Technologies 2014 annual meeting on February 24, 2014 in Washington, D.C. The study, which was sponsored by Boston Scientific, was recognized as a Top Ten Abstract at the meeting and is featured in the February 2014 Journal of the American College of Cardiology: Cardiovascular Interventions.
The multicenter, single arm OMEGA trial took place at 37 sites in Europe and the U.S., enrolling 328 patients aged 65 and older with higher risk profiles than previous bare mental stent trials. All patients in the study received an OMEGA/REBEL bare mental stent. UVM/Fletcher was one of the sites with leading enrollment for this study.
Watkins and his coauthors report that after nine months, participants with the OMEGA/REBEL stent appear to both have low rates of complications and lower than expected rates of scar tissue requiring further procedures. This supports safety and efficacy of the novel, platinum chromium OMEGA/REBEL bare metal stent for the treatment of coronary artery disease.
“In this trial, a new generation of bare metal stents appear to have better than expected long-term outcomes for patients, nearly matching the historical performance of drug-eluting stents,” says Watkins. “This is encouraging news for patients who may have problems with the more complex medical regimen used with drug-eluting stents.”
The next step, he says, will be publication of the trial’s results, with the anticipation of clinical use of this new bare mental stent in the near future.
Gene Therapy for Heart Failure Trial
Congestive heart failure patients are the focus of one of Watkins’ currently active clinical trials, which is examining the safety and benefit of a gene therapy treatment designed to increase the heart’s pumping function. UVM/Fletcher Allen is one of five U.S. sites enrolling patients in the trial, which is supported by the National Institutes of Health’s National Heart, Lung and Blood Institute and Renova Therapeutics.
The American Heart Association estimates that 5.7 million people suffer from heart failure, a condition characterized by a weakening and enlargement of the heart wall, which prevents the heart’s left ventricle from pumping enough blood.
For this trial, Watkins and colleagues are seeking to determine whether a procedure transferring genes for a heart protein known to make the heart beat stronger can increase heart pumping in patients with moderate to severe heart failure.
The gene product – coding for a protein called adenylyl cyclase type 6 or AC-6 – is delivered to hearts cells by the coronary arteries during cardiac catheterization. Once introduced, the researchers expect that the treatment will increase production of this heart protein, thereby improving the heart’s pumping function. Pre-clinical studies have shown favorable results.
Watkins looks forward to launching another intracoronary treatment trial, currently in the planning phase, that will test the effectiveness of allogenic – or donated – heart stem cells in improving heart pumping following heart attack.
For information about current clinical trials, contact Michaelanne Rowan, R.N., cardiology research supervisor, at Michaelanne.Rowan@vtmednet.org or 802-847-4746.