Boston Sci device cuts heart events, not deaths

* 41 pct reduction in heart failure events in clinical trial

* No mortality benefit, reflecting low death rate in study

* Result may boost market, but some heart doctors wary

BARCELONA, Sept 1 (Reuters) - Early intervention with Boston Scientific's BSX.N implantable devices, called cardiac resynchronisation therapy (CRT), helped patients' hearts work better but did not reduce mortality in a keenly awaited clinical trial.

The study, details of which were released on Tuesday, may grow the market for the expensive devices, which coordinate heart pumping through electrical pulses, beyond the sickest heart failure patients.

But some cardiologists gathered in Barcelona, where the data was presented at the annual meeting of the European Society of Cardiology, cautioned against rushing to use them too widely.

Boston Scientific first announced in June that its MADIT-CRT study of more than 1,800 patients had met its main goal.

The full details showed that the CRT devices when combined with a defibrillator, or ICD, cut the risk of death or heart failure interventions by 34 percent in asymptomatic and mild heart failure patients compared with defibrillators alone.

The benefit was driven not by a difference in deaths but by a 41 percent reduction in heart failure events, which investigators defined as those requiring hospitalisation or intervention with intravenous medication on an outpatient basis.

The results were also published online in the New England Journal of Medicine.

Principal investigator Arthur Moss of the University of Rochester Medical Center said the result was “striking”, adding the effect was more marked in women than in men.

The lack of impact on mortality was not surprising because the death rate in both groups of patients, who were followed for an average 2.4 years, was under 3 percent, he said.

“It will take time to really sink in. I think there will be a progressive avalanche (of increased use) because heart failure societies have been very frustrated in the last four or five years at having no new drugs for heart failure,” he said.

But Douglas Zipes of Indiana School of Medicine, the past president of the American College of Cardiology, was wary.

“This study may widen the net to capture more patients for CRT-ICD. But whether that is appropriate should be questioned. It is likely that our indications for ICD and now maybe for CRT as well are already too broad,” he said.

Nearly 22 million people worldwide suffer from heart failure, in which the heart struggles to pump blood around the body, and early-stage heart failure patients make up about 70 percent of the total.

The study has been highly anticipated by investors because of its potential to boost sales of more expensive ICDs that also have the CRT feature. Those so-called CRT-D devices cost $25-35,000, or about $7-$8,000 more than a standard ICD.

Growth in the ICD market has slowed in recent years after a wave of product recalls tempered their use.

According to American Heart Association president Clyde Yancy of Baylor University Medical Center in Dallas, cost will be key in deciding future use in less ill patients.

“We’re talking about a very expensive technology and a very large denominator of patients,” Yancy said.

Boston Scientific competes with Medtronic MDT.N and St. Jude Medical STJ.N in the market for devices that manage heart rhythms.

Standard defibrillators involve two electrical lead wires that extend to the heart’s right ventricle. CRT-D devices add a third lead that attaches to the left ventricle, helping it coordinate pumping of the chambers and improve efficiency. (Editing by Dan Lalor)