The 'Echo Heart Failure Score': an echocardiographic risk prediction score of mortality in systolic heart failure

Abstract

Aims: Although many transthoracic echocardiographic (TTE) measurements have been shown to predict outcome in heart failure (HF), whether incremental risk prediction is afforded by their combination is unknown. We developed a simple echocardiographic risk score of mortality in HF patients.

Methods and results: We performed TTE in 747 systolic HF patients followed-up for 34 ± 23 months. The Cox hazard model was used to evaluate the association between 14 TTE parameters and death. The Echo Heart Failure Score (EHFS) was derived by assigning the value of 1 to each independent predictor when present, and 0 when it was absent, and then by summing the number. The 3-year risk prediction improvement was tested by adding the EHFS to a model containing clinical predictors, and by calculating the C index and net reclassification improvement (NRI). Five baseline TTE variables (end-systolic volume index, left atrial volume index, mitral E-wave deceleration time, tricuspid annular peak systolic excursion, and pulmonary artery systolic pressure) remained independent predictors of mortality. The mortality rate (per 100 patients/year) significantly increased with EHFS ranging from 0 to 5 (EHFS = 0, 2.7%; 1, 5.2%; 2, 10.1%; 3, 13.7%, 4, 29.7%; 5, 36.9%; P < 0.0001). Patients with EHFS ≥3 had a mortality hazard ratio of 3.58 (95% confidence interval 2.74-4.78) compared with EHFS <3. Adding EHFS to the base model improved the C index (from 0.74 to 0.81, P < 0.0001), yielding a continuous NRI of 0.63 (P < 0.0001).

Conclusions: The EHFS, an easily obtainable echo score, improved risk prediction of death over traditional prognostic factors in systolic HF patients, and it may prove useful for risk stratification.

Keywords: Echocardiography; Heart failure; Prognosis; Risk score.