Cardiac resynchronization therapy in heart failure trial (CARE-HF)

Cardiovascular News

CRT benefits greater in presence of more severe cardiac dyssynchrony, low SBP3

August 2007

MedWire News: Cardiac resynchronization therapy (CRT) provides greater benefits in heart failure (HF) patients with more severe cardiac dyssynchrony and low systolic blood pressure, report CARE-HF investigators.

Having already found that CRT reduces morbidity and mortality in patients with HF and cardiac dyssynchrony in the CARE-HF (CRT in HF) trial, Nick Freemantle (University of Birmingham, UK) and team used risk modeling to define patient characteristics associated with the primary outcome of death from any cause or unplanned cardiovascular hospitalization.

CARE-HF included 813 patients who were followed-up for a mean of 29.4 months.

The results, reported in the European Heart Journal, showed that ischemic etiology of HF, more severe mitral regurgitation, and increased N-terminal pro-brain natriuretic peptide were independent predictors of the primary outcome, with respective hazard ratios (HRs) of 1.89, 1.71, and 1.31.

Only echocardiographically determined interventricular mechanical delay (IVMD) and SBP predicted response to CRT, with “modest statistical precision,” the authors note.

Patients with increasing SBP appeared to receive less benefit from CRT (HR=1.02) while patients with more severe IVMD appear to benefit more from treatment (HR=0.99), they report.

“This more detailed analysis provides evidence that IVMD and to a lesser extent SBP predict patients’ response to CRT,” Freemantle and co-authors write.

They caution that the model used is “exploratory” and the interactions between CRT and either IVMD or SBP are not particularly strong. But they note that the influence of IVMD on CRT effects are “consistent with the view that IVMD is a more precise physiological marker of cardiac dyssynchrony, the problem that CRT is designed to treat, than any other variable analyzed.”

Thus, they say, IVMD could potentially be used as an inclusion criterion in future randomized controlled trial examining the effects of CRT in patient populations not included in CARE-HF, such as those with less severe symptoms or shorter QRS intervals.

Link:

Eur Heart J 2007; 28: 1827-1834