European CRT Survey: Indications in Real Life Often Ahead of Guidelines

September 08, 2009

September 8, 2009 (Barcelona, Spain) - It seems that European cardiology has faith in cardiac resynchronization therapy (CRT), with stand-alone CRT devices or those that defibrillate (CRT-D) often going into groups for which there are no strong evidence-based indications. They include the very elderly and those not in sinus rhythm or with only mild heart failure and those without ECG-defined ventricular dyssynchrony, according to a survey of CRT practice patterns in 2008 through June 2009, in a dozen European countries, reported here at the European Society of Cardiology 2009 Congress.

The European CRT Survey included only patients with successful implantation procedures--no data were collected on failed procedures or patients screened for CRT but then excluded. With that caveat, complication rates were similar to those in the major CRT randomized trials such as COMPANION, CARE-HF, REVERSE, and MADIT-CRT, observed Dr Nigussie Bogale (University of Bergen, Stavanger, Norway) when reporting the results.

Nearly lost in the excitement over MADIT-CRT's findings at this meeting of significant clinical and reverse-remodeling benefits from CRT in patients with mild heart failure has been perspective on how the device therapy is actually used outside the world of clinical trials.

"In our almost two and a half thousand patients, we saw some very interesting things," the survey's lead investigator, Dr Kenneth Dickstein (University of Bergen), told heartwire . "A fourth of our patients had atrial fibrillation, and we have zero [randomized-trial] data on such patients. Almost a fourth had a previous device, so they were getting an upgrade." The major trials don't address them either.

"And probably most important, almost 20% have a narrow QRS complex, under 130 ms," he said. Those cases were probably at centers that put a lot of weight on dyssynchrony as measured by echocardiography, Dickstein observed. Dyssynchrony by echo can often be found in patients who don't meet the ECG definition.

Mechanical dyssynchrony wasn't even assessed in 46% of the cohort, according to Dickstein.

"This is how people are actually doing it," he said. "What's really happening is that doctors are exploring wider indications, they're extrapolating." Dickstein attributes that to "the power of the anecdotal experience," which has convinced many clinicians that CRT can produce striking clinical improvements in heart-failure patients even when used off-label.

The survey looked at 2438 successful CRT implantations in 12 European nations and Israel, including 571 in Italy and 321 in Sweden, the countries contributing the most patients.

Findings in the European CRT Survey: Features of device recipients

Parameters Baseline prevalence (%)
Age >75 31
HF hospitalization within previous year 57
Prior device implantation 26
Atrial fibrillation 23
QRS <120 ms a 9
QRS 120–129 ms 10
NYHA class 1 b 2
NYHA class 2 20
LVEF >35% 17
Moderate to severe mitral regurgitation 35

a. mean baseline QRS in the survey 157 ms
b. mean baseline LVEF in the survey 27%

There were few complications; the rates of bleeding and pneumothorax were each 1% and the rates of pocket hematoma and lead dislocation were 3% each.

Dr Angelo Auricchio (Fondazione Cardiocentro Ticino, Lugano, Switzerland), one of the survey's lead participants, observed that there are at least non–randomized-trial data supporting CRT in patients with AF or mild disease. A number of them suggest that "patients with atrial fibrillation may receive the same degree of benefit, reduction of hospitalization, as patients in sinus rhythm."

The guidelines recognize this by giving CRT a qualified recommendation in the presence of AF based on a reduced level of evidence, which explains why a large percentage in the survey had AF. "It's exciting, because it's what we'd like to see."

Prevalence of AF, very narrow QRS, and ischemic disease by age in the European CRT Survey

Parameter Age <75 (%) Age >75 (%) p
Atrial fibrillation 21 28 <0.0001
QRS <120 ms 10 5 <0.01
Ischemic disease 48 57 <0.001

As discussant following Bogale's presentation of the survey, Dr Jean-Claude Daubert (University of Rennes, France) said that the CRT use in NYHA class 1-2 heart failure "is clearly in anticipation of [revised] guidelines" and possibly based on the REVERSE trial's finding of a benefit in such mild disease. However, he cautioned, "We don't know exactly what the risk/benefit ratio is of using CRT in that relatively low-risk population."

Also, he said, "We cannot today recommend the use of CRT in the population of narrow-QRS patients." Daubert pointed out that no benefit was seen the RethinQ study, which entered patients with a QRS <130 ms.

The survey also suggests that in Europe, at least, CRT is underused in women and the very elderly, he said. And it carries a low risk of complications and so appears "relatively safe," although there would have been a better fix on safety if it hadn't excluded patients with failed implantations or VT/VF.

As a window into current European practice, he said, the survey "is a very good start."

To access complete presentation slides (pdfs), click here.

Bogale reported that "some authors" of the survey have received grants or honoraria from Biotronik, Boston Scientific, Medtronic, Sorin, and St Jude Medical. Daubert discloses receiving consulting fees from Medtronic and St Jude Medical and honoraria for speaking from Biotronik, Medtronic, Sorin Group, and St Jude Medical.