Medical Device Daily

A clinical study presented at the European Society of Cardiology (Sophia Antipolis, France) meeting in Barcelona has the potential to rewrite practice guidelines worldwide for implantation of devices to assist heart failure patients.

Panos Vardas, president of the European Heart Rhythm Association (EHRA), tried to slow the enthusiasm among presenters by stressing during a press conference that the results of the trials, which he acknowledged are practice-changing, need to be validated by publication in peer-reviewed journals.

The MADIT-CRT study, sponsored by Boston Scientific (Natick, Massachusetts), investigated whether patients with mild heart failure do better if they are implanted with a cardiac resynchronization therapy defibrillators (CRT-D) device, combining cardiac resynchronization therapy with defibrillation, than if they only receive the traditional and widely used implantable cardioverter defibrillator (ICD) device.

The trial led by Arthur Moss, MD, from the University of Rochester Medical Center (Rochester, New York) enrolled 1,820 patients from 110 centers in 14 countries who were randomized to receive either CRT-D or ICD.

Early intervention with CRT-D in mild heart failure slows the progression of heart failure, Moss reported, producing significant reductions in death and heart failure interventions, according to results from the MADIT-CRT trial.

Moss reported to colleagues at ESC 2009 that during a follow-up period that averaged 28 months, 17.2% of patients in the CRT group experiences either a heart failure event or death, compared to 25.3% in the ICD group.

The superiority of CRT-D therapy was found to be present in all patient sub-groups, including those with ischemic and non-ischemic types of heart disease, as well as in males and females, younger and older patients, and those with mild and more advanced heart dysfunction.

"Cardiac resynchronization therapy was dramatically effective in this large study population, with a 34% reduction in the risk of all-cause mortality or heart failure," he said, adding "The benefit is dominated by a 41% reduction in heart failure events."

"This result validates a new indication for cardiac resynchronization therapy in the prevention of heart failure in at-risk asymptomatic or mildly symptomatic cardiac patients," said Moss.

"It seems likely that this preventive CRT-D therapy will have widespread application and utilization," he concluded.

Around half of all patients with heart failure die suddenly due to ventricular arrhythmias, leading to the recommendation in both European and American clinical practice guidelines that survivors receive an ICD.

About one third of patients with low ejection fractions have abnormal electrical activation of the left ventricle resulting in dyssynchronous contraction of the walls of the left ventricle, leading to suboptimal ventricular filling, decreased stroke volume facilitation of mitral regurgitation, increased wall stress, and delayed relaxation, which has been associated with increased morbidity and mortality.

CRT-D was designed to simultaneously pace both the left and right ventricles in a synchronized manner, resulting in acute hemodynamic benefits.

"MADIT-CRT is providing insight into the potential of CRT-D therapy to intervene earlier in the natural progression of heart failure," said Vardas, adding that about 60% of all heart failure patients in Europe fall into the criteria used for patients enrolled into the study.

Vardas also expressed a concern that it may prove difficult to have CRT-D technology implemented throughout Europe.

"Currently, huge differences exist in the implementation of the guidelines from country to country," he said.

New data on Europe's 'burden of heart failure'

About 25,104 physicians and surgeons attending the ESC meeting participated in 600 hours of scientific sessions listening to presentations delivered by 3,800 speakers.

A key touchstone for presenters is the rapidly aging population of Europe that will only increase the burden of cardiovascular disease for national health systems, which is estimated to cost the economies of the 27 members of the European Union 1192 billion ($275 billion) per year with 57% of that figure accounted for by direct healthcare costs.

At ESC 2009, a recently completed analysis of more than one million hospital cases in Sweden over 16 years revealed that the impact of heart failure is as great as the most common and feared forms of cancer in respect to the risk of being hospitalized for the first time, poor overall survival and the number of premature life-years lost.

The ratio of heart failure to cancer cases overall was 1.5 to 1, and 59% of patients with heart failure died within five years of their first hospital admission, a lower survival rate than for the combined cancer population.

The estimated cost of heart failure due to loss of life and quality of life combined was SEK 16.4 billion ($2.3 billion) compared to SEK 5.3 billion ($746 million) and SEK 4.1 billion ($577 million) for lung and prostate cancer, respectively.

Novel study examines AF on a global scale

The Thrombosis Research Institute, a charitable foundation affiliated with Queen Mary University of London reported at ESC 2009 an innovative research initiative to understand the burden of atrial fibrillation (AF) called GARFIELD, the Global Anticoagulant Registry in the Field.

The GARFIELD Registry will follow 50,000 patients newly-diagnosed with AF who are also candidates for anticoagulant therapy to prevent blood clots leading to stroke over a six-year period in 32 countries.

A set of patients from 1,000 centers in 50 countries will be included in the registry.

Clinical sites will be randomly selected to participate to avoid the selection of only sites expert in AF management in order to provide a real-world view of how the disease AF is being managed across all care settings, such as hospitals, emergency departments, anticoagulant clinics and general practice settings.

"We need to better understand AF if we are to begin tackling its consequences in a meaningful way," said Prof. Ajay Kakkar, the director of the institute and Professor of Surgical Sciences at Queen Mary University.

In the European Union 4.5 million people have persistent AF where parts of the atria emit uncoordinated electrical signals that cause the chambers to pump too quickly and irregularly, thereby not allowing blood to be pumped out of the atria completely.

As a result, blood may pool and lead to thrombosis, or creating clots that could potentially lodge in an artery particularly in the brain leading to a stroke.

People with AF have a five times higher risk of suffering a stroke than the general population, and are also at high risk for heart failure, chronic fatigue and other heart rhythm problems.

"Anticoagulant therapy may be necessary for preventing thromboembolic stroke, yet few at-risk patients probably receive appropriate and potentially life-saving prophylactic therapy," Kakkar said, adding that GARFIELD aims to better understand the effectiveness and application of therapies.

Remote ICD monitoring speeds detection

The remote monitoring of patients with implantable cardiac devices (ICD) is believed to be a remedy for improving patient safety, streamlining hospital visits and enhancing the surveillance of both device- or patient-related clinical data.

Yet there has not been sufficient clinical evidence to support these assumptions about remote monitoring.

The TRUST trial presented at ESC 2009 claims to be the first prospective large scale effort to test such technology.

Centered on an internet-based, wireless remote monitoring system using the GSM telephone network called Biotronik Home Monitoring, TRUST is a randomized trial of 1,443 patients enrolled from 105 North American sites.

The study measured how reliably daily telemetric surveillance, which is automatic as it does not require patient activation, reported relevant clinical events, such as asymptomatic atrial fibrillation.

Niraj Varma, MD, with the Cleveland Clinic and the principal investigator for the TRUST trial reported that remote monitoring event notifications were evaluated in a median of three days compared to more than 30 days with conventional care, providing earlier detection and notification of both symptomatic and asymptomatic arrhythmic events and enabling earlier physician intervention.

The event notifications were triggered infrequently and did not overburden physician or clinic resources with distracting information, he reported.

Biotronik (Berlin) said it has an installed base of 200,000 home monitoring systems in 65 countries that are compatible with the company's pacemakers, ICD and cardiac resynchronization therapy devices.