New echo heart failure index better stratifies risk

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Researchers have identified five transthoracic echocardiographic measurements that independently predict heart failure in patients with stable CAD and combined them as an index that might be useful for risk stratification and serial observations.

Steven M. Stevens, MD, and colleagues at the University of California, San Francisco, and the VA Medical Center, San Francisco, performed transthoracic echocardiography (TTE) in 1,024 outpatients with stable CAD enrolled in the Heart and Soul study and followed them for 4.4 years (J Am Coll Cardiol Img 2009;2:11–20).

They evaluated the association of 15 TTE measurements with subsequent heart failure hospital stay. Of the 15 variables, five measurements were independent predictors of heart failure: left ventricular mass index (LVMI), left atrial volume index (LAVI), mitral regurgitation (MR), left ventricular outflow tract velocity-time integral (VTI LVOT), and diastolic dysfunction (DD).

In multivariate analysis, each of the five measurements independently predicted heart failure:

  1. LVMI >90 g/m2
  2. pseudo-normal or restrictive DD
  3. VTILVOT 29 ml/m2.

Combining these measurements, the Heart Failure Index ranged from 0 to 8, representing risk as follows: 3 points for LVMI, 2 points for DD, and 1 point for VTI LVOT, MR, and LAVI.

Among participants with 0 to 2 points: 4 percent had heart failure hospital stays; 3 to 4 points: 10 percent; 5 to 6 points: 24 percent; and 7 to 8 points: 48 percent.

“In creating this index, we initially studied a group of 15 historically and intuitively promising echocardiographic measurements. By choosing the most predictive among them, we eliminated those that were statistically redundant, leaving those that were independent predictors of heart failure,” wrote the authors.

Researchers also said that this Heart Failure Index “presents compelling evidence that these measurements be routinely performed in most clinical settings.”

Stevens and colleagues said that ejection fraction (EF) was absent from the index because there was not a large proportion of patients in this study with reduced EF. They noted the index’s “unique role in identifying diastolic heart failure given the relatively preserved EF in this patient population and that DD, LV mass, and left atrial volume make up 6 of the index’s 8 points.”

They concluded that the TTE Heart Failure Index might be most suitable for predicting heart failure in a patient population with relatively preserved systolic function.