Trans-Thoracic Echocardiographic Parameters for Prognostic Assessment Across the Spectrum of Heart Failure

Abstract

Heart failure with increasing life expectancy has become the leading cause of morbidity and mortality in modern day world, begetting great economic burden. Usually diagnosed by specific criteria, Framingham’s being the most commonly employed, heart failure has been classified on the basis of left ventricular ejection fraction measured by transthoracic echocardiography as heart failure with preserved ejection fraction (HFpEF, LVEF ≥ 50%), heart failure with mid-range EF (HFmrEF, LVEF 41-49%) and heart failure with reduced EF (HFrEF, LVEF ≤ 40%), constituting the “spectrum”. For the diagnosis of HFpEF, elevated biochemical markers and presence of cardiac structural abnormalities or diastolic dysfunction are also required whereas for the other types only ejection fraction, with appropriate symptoms/signs are needed. It is quite clear that echocardiography plays a central role in diagnosis and classification of heart failure. Mostly, of the prognostic markers mortality and hospitalization have been assessed in clinical trials. Here also echocardiography plays a prominent role and every modality of it (with numerous parameters) including M-mode, 2D, color, spectral and tissue Doppler along with recent addition of strain imaging provide important clues. These clues not only work for heart failure as a whole but also for the individual classes. Many studies have provided insights into the comparative efficacy of these markers across the spectrum. The prognostic power of these echo parameters has been assessed either individually or in combination. Various scoring systems have also been formulated. An individual patient can transit through the classes of heart failure over time and certain echo parameters provide an indication in this regard as well. Structural parameters of both sides of the heart along with functional and hemodynamic assessment provide prognostic insights with strain measures showing superiority. No large-scale clinical trial has yet been done in which all the parameters across the spectrum of heart failure have been studied. An appraisal of clinically important echo markers for prognostic assessment across the spectrum is the subject of this descriptive review.