ESC guidelines give top recommendation to CRT for mild heart...

ESC guidelines give top recommendation to CRT for mild heart failure
SEPTEMBER 1, 2010 | Steve Stiles


Stockholm, Sweden - An update to the European guidelines for use of device therapy in heart failure extends its strongest, most evidence-based recommendationclass I, level of evidence Afor use of cardiac resynchronization therapy (CRT) from the traditional NYHA class 3-4 indication to include patients with "mild" NYHA class 2 heart failure [1].
The class I A recommendation in NYHA 2 heart failure, for curtailing disease progression rather than "morbidity or mortality reduction" as allowed in NYHA 3-4, is based on the randomized, controlled REVERSE and especially MADIT-CRT studies, whichas previously covered by heartwireincluded NYHA class 1-2 patients and saw CRT significantly improve HF hospitalization or death and HF-free survival, respectively.

The expanded indication in the European guidelines, which do not include NYHA class 1 heart failure or have a restriction based on left bundle-branch block (LBBB), varies somewhat from what was proposed for expanded indications in the US in March by an an FDA advisory panel. As reported then by heartwire, the panel voted unanimously in favor of making CRT indicated in NYHA class 2 and, in patients with ischemic heart failure, class 1 with an LVEF <30% and a QRS duration >130 ms. Added to the requirements was LBBB, which emerged as a marker of good response in a MADIT-CRT post hoc analysis.

The new document, released here at the European Society of Cardiology 2010 Congress and published online by the organization in European Heart Journal August 27, 2010, restricts the QRS-interval requirement from >120 ms for NYHA 3-4 patients to >150 ms for those in class 2. Both I A recommendations stipulate that the patient must have an LVEF <35% and be on optimal medication and in sinus rhythm.

In general, the guidelines give about equal weight to CRT therapy that includes (CRT-D) or does not include a defibrillator (CRT-P).

Dr Kenneth Dickstein (University of Bergen, Stavanger University Hospital, Norway), chair of the task force that wrote the new guidelines, told heartwire that the expanded I A indication is "revolutionary" in derivation from the clinical-trial evidence. Traditionally, guidelines are based on outcomes in patients defined by the entry criteria of the relevant clinical trials. But it's common for patients actually enrolled to differ substantially from the prospectively defined ideal.

"We've done something new in this guideline. It's the first time, instead of taking the description of the cohort in the protocol literally, we looked at the cohort that was actually included in the trial and evaluated how those patients did," he said.

For example, Dickstein noted, MADIT-CRT allowed patients in NYHA class 1 or 2 to enter the trial, but ultimately class 1 patients, who typically have a history of symptoms but are symptom-free on medical therapy, accounted for only 15% of the population. In subgroup analysis, they did not show a significant benefit from CRT.

Also, the trial's inclusion criteria included a QRS duration >130 ms, yet the CRT benefit was concentrated in the majority of patients with QRS >150 ms, a cut point that was prospectively defined.

So the new class I A recommendation, Dickstein said, was limited to patients who showed a high likelihood of a good response to CRT in the trial: NYHA class 2, but not class 1, with a QRS duration >150 ms.

On the other hand, women, especially those with LBBB, showed an especially pronounced clinical response to device therapy in MADIT-CRT compared with men. But those data have yet to be formally peer reviewed and published, and the analysis by sex wasn't prespecifiedso the guidelines update doesn't consider them, according to Dickstein.

Also new to the European guidelines are class IIa recommendations for CRT in patients with permanent atrial fibrillation (AF) who are either pacemaker dependent with bradycardia or after atrioventricular-nodal ablation.

Finally, observed Dickstein, a class IIb recommendation for left ventricular assist device (LVAD) destination therapy is included for patients with NYHA class 3b-4 heart failure and an LVEF no higher than 25%.

For destination therapy, he said, continuous-flow pumps like the Thoratec Heartmate 2 "are certainly superior" to pulsatile LVADs like the same company's outmoded Heartmate XVE.

http://www.theheart.org/article/1117827.do

*HTWR is quickly becoming more dominant in Europe than THOR*