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Late-Breaking Clinical Trials

The following are short explanations of late breaking clinical trials from today's trials sessions at the American College of Cardiology meeting in Orlando, Florida.

In-stent renarrowing: are balloons or more stents the better treatment?

(ORLANDO, FLA.)óRapid growth in the use of coronary stents, tiny metal scaffolds that can prop open heart vessels that have been narrowed by disease, has given rise to a relatively new and hard-to-treat problem. In-stent restenosis occurs when scar-like tissue grows through the stent to re-narrow and sometimes block the vessel, often giving the patient chest pain. A randomized trial has sought to determine which of the two most common treatments for in-stent restenosis—insertion of a new stent or inflation of an angioplasty balloon—is more likely to keep the vessel open.

In the "Restenosis Intra-Stent: Balloon Angioplasty vs. Elective Stenting" (RIBS) trial, 450 patients with stented but renarrowed heart vessels were randomly assigned to repeat therapy with either angioplasty balloons or additional stenting. Early results from the trial, which was conducted at 24 institutions in Spain and Portugal, showed that repeat stenting initially opened the heart vessels wider.

More important, however, is whether one of the treatments is better at preventing further vessel renarrowing after six months. Dr. Fernando Alfonso, Universitario San Carlos, Madrid, reported those more conclusive findings from the RIBS trial on Sunday, March 18, at 8:45 a.m. at the American College of Cardiology 50th Annual Scientific Session in Orlando, Fla.

Trial tests radiation therapy for new and repeat coronary stenting procedures

(ORLANDO, FLA.)—Several devices are now available for applying radiation to recurrent narrowings within coronary stents—or in-stent restenoses—at the same time they are also treated with angioplasty balloons or additional stents. But it is unknown whether this form of radiation therapy, called intracoronary brachytherapy, will also prevent renarrowing of coronary lesions that are being stented for the first time. That may change with the reporting of the "Beta-Cath System Trial," which has tested the effectiveness of brachytherapy in patients with narrowings in either previously treated or yet untreated heart vessels.

"This is the only trial in the world with sufficient statistical power to test the potential for radiation therapy for treating coronary lesions that have not previously been stented," said Dr. Richard E. Kuntz.

If the study shows brachytherapy to reduce the risk of renarrowing after first stenting procedures as well as later ones, "it could extend the radiation treatment to the broader population of patients with new lesions," said Dr. Kuntz, who is with the Division of Clinical Biometrics at Brigham and Women's Hospital, Boston.

Dr. Kuntz presented the results of the Beta-Cath System Trial at 8:58 a.m. on Sunday, March 18, at the American College of Cardiology 50th Annual Scientific Session in Orlando, Fla.

Final results of heart laser-channel technique randomized trial to be reported

(ORLANDO, FLA.)—Many inconclusive studies have suggested that the practice of using lasers to create channels in heart muscle, called transmyocardial laser revascularization, seems to improve the clinical condition of patients with advanced coronary heart disease. But last year the preliminary findings of a randomized, double-blind, controlled trial, the kind of study experts agree produces the most reliable data, suggested that the technique does not work. The final results of that study, including patient outcomes observed during the 12 months following the treatment, are to be reported at the American College of Cardiology 50th Annual Scientific Session in Orlando, Fla.

The unique laser treatment, also called direct myocardial revascularization or DMR, calls for a fiberoptic laser catheter to be threaded through the arteries into the heart chambers. The laser is used to bore a series of holes into the heart muscle. How those laser channels might eventually lead to reductions in the severity of coronary disease symptoms has long been something of a mystery.

When Dr. Martin B. Leon, Lenox Hill Heart and Vascular Institute, New York City, reported early results from the "DMR in Regeneration of Endomyocardial Channels Trial" (DIRECT) last year, DMR was no more effective than a placebo sham-DMR procedure. Dr. Leon made his presentation of final outcomes from the DIRECT trial at the ACC session on Sunday, March 18, at 9:10 a.m.

Randomized trial tests bypass surgery against coronary stenting for multivessel disease

(ORLANDO, FLA.)—Coronary stenting is usually preferred over bypass graft surgery in patients with symptoms caused by narrowings in one main heart vessel. But which of the two revascularization approaches may be better for patients with such disease in multiple heart vessels remains controversial. Now, preliminary findings from the "Stent or Surgery" (SoS) trial suggest that patients with such multivessel coronary disease may fare better over the long term if they get bypass surgery rather than stenting.

In the SoS trial, nearly 1,000 patients with multivessel coronary disease who were eligible for either stenting or bypass surgery were randomly assigned to undergo one or the other treatment. The trial's investigators are comparing the rates of such major clinical events as death, heart attack, and development of chest pain in the two groups over the course of one to four years. Early analyses, conducted before the patients had been followed for the one-year minimum required by the trial's design, suggest a major advantage for bypass surgery.

Dr. Rodney Stables reported the more conclusive one-year results of the SoS trial at the American College of Cardiology 50th Annual Scientific Session in Orlando, Fla. Dr. Stables, of the Royal Liverpool University Hospital and the Cardiothoracic Centre, Liverpool, United Kingdom, presented his results at 9:22 a.m. on Sunday, March 18.

Trial compares surgery, angioplasty, and drug therapy for multivessel heart disease

(ORLANDO, FLA.)—Of the three common treatments for patients who have symptoms cause by narrowings in at least two major heart vessels—bypass surgery, angioplasty, or medications only—none has been conclusively shown to be produce significantly better outcomes than the others. But early findings from a randomized comparison of the three approaches now suggest that the late risk of serious clinical events like heart attack or death is about the same with surgery as with drug therapy alone.

"Medical therapy alone is a reasonable alternative, with no higher risk of morbidity or mortality than that associated with bypass surgery," said Dr. Whady Hueb, principal investigator of the "Medicine, Angioplasty, or Surgery Study" (MASS-II). That conclusion is based on one-year follow-up data for about 90 percent of the study's 1,086 patients who had symptoms caused by multi-vessel coronary disease and were randomly assigned to one of the three treatments.

Dr. Hueb, of the Heart Institute, University of Sao Paulo, Brazil, presented the preliminary results of MASS-II on Sunday, March 18, at 9:34 a.m. at the American College of Cardiology 50th Annual Scientific Session in Orlando, Fla.

Radiation treatment tested against recurrent narrowings in stented bypass grafts

(ORLANDO, FLA.)—The lengths of vein or artery surgically implanted to bypass blood flow around narrowings in the major heart vessels can also start to close off from disease. Such restenosis or renarrowing in bypass grafts can be treated with coronary stents, but the risk that recurrent lesions will grow within those stents is frustratingly high. Now, a radiation therapy technique that has been approved for the treatment of in-stent restenosis in native heart vessels has been tested for effectiveness in bypass grafts.

In the "Washington Radiation for In-Stent Restenosis Trial for Saphenous Vein Grafts" (SVG-WRIST), 120 patients with recurrent, diffuse narrowings in stented bypass grafts were randomly assigned to undergo the radiation treatment, called brachytherapy, or a sham brachytherapy procedure that served as a placebo. The radiotherapy source consisted of a string of pellets containing iridium-192, an emitter of gamma radiation. The seed string is inserted through a catheter and temporarily positioned within the restenotic stented bypass graft.

Several devices for performing brachytherapy were approved last year by the U.S. Food and Drug Administration specifically for use on restenoses within stents that had been previously placed in native coronary arteries.

Dr. Ron Waksman, of the Washington Hospital Center in Washington, D.C., presented preliminary results of SVG-WRIST at 9:46 a.m. on Sunday, March 18, at the American College of Cardiology 50th Annual Scientific Session in Orlando, Fla.

Defibrillator implants tested in patients with hearts dilated from unknown causes

(ORLANDO, FLA.)—Patients with dilated heart chambers, common in several types of advanced cardiac disease, can be at increased risk of dying suddenly from an abnormal heart rhythm. Implantable devices that deliver shocks to return the rhythm to normal are often used to lower their risk of death. But the extent of this strategy's effectiveness is not well understood.

Now, a small randomized study suggests that preventive defibrillator implantation does not prolong survival in a specific subset of such patients, those with hearts dilated from unknown causes, or idiopathic dilated cardiomyopathy (DCM).

The "Cardiomyopathy Pilot Trial" (CAT), which enrolled 104 patients with idiopathic DCM and severely decreased heart function, "did not provide evidence in favor of prophylactic implantable cardioverter-defibrillator implantation" in this group, according to Dr. Karl Heinz- Kuck, St. Georg Hospital, Hamburg, Germany.

Dr. Kuck presented the results of the CAT study, which followed patients for as long as seven years, on Sunday, March 18, at 8 a.m. at the American College of Cardiology 50th Annual Scientific Session in Orlando, Fla.

Pacing technique and drug therapy are synergistic for drug-resistant atrial fibrillation

(ORLANDO, FLA.)—Patients with chronic atrial fibrillation may also have bradyarrhythmias, a slow heartbeat that is usually treated by implantation of a pacemaker with or without the use of medications. It has been known that certain atrial pacing techniques seem to improve the effectiveness of such antiarrhythmic drugs in suppressing atrial fibrillation episodes.

One of the largest prospective, randomized studies of these issues has found that a specific, nonstandard atrial pacing strategy prolonged the interval between episodes of drug-resistant atrial fibrillation better than did other standard atrial pacing methods.

"This trial for the first time establishes a synergistic relationship between an atrial pacing technique and antiarrhythmic therapy in patients with drug-refractory atrial fibrillation," said Dr. Sanjeev Saksena, who is director of the Cardiovascular Institute at the Atlantic Health System, Millburn, N.J., and professor of medicine at Robert Wood Johnson School of Medicine.

"It shows that dual-site right atrial pacing suppresses the atrial fibrillation that breaks through despite drug therapy," said Dr. Saksena, "allowing patients who would otherwise be considered treatment failures to maintain control of their arrhythmia."

Dr. Saksena presented the results of the "Dual-Site Atrial Pacing for Prevention of Atrial Fibrillation" trial (DAPPAF) on Sunday, March 18, at 9:15 a.m. at the American College of Cardiology 50th Annual Scientific Session in Orlando, Fla.

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