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Echocardiographic Predictors of Outcome in Patients With Dilated Cardiomyopathy


As the burden of heart failure (HF) and cardiomyopathies continues to rise, the clinical need for early detection of individuals at risk becomes critical. Identification of patients with a poor prognosis allows for early interventions (primary prevention, medications, devices) that can dramatically change the course of their disease by improving quality of life and prolonging survival. Multiple predictors of outcomes in this population have been described ( Table 67.1 ). Although traditional clinical variables and biomarkers have been used to risk-stratify, , the addition of echocardiographic variables to clinical evaluation has shown to be of significant value.

Table 67.1
Predictors of Poor Outcomes in Patients With Dilated Cardiomyopathy
Clinical predictors Older age
Poor functional capacity (NYHA, 6-min walk test, VO 2 max)
S3
Cardiac cachexia
Poor perfusion (e.g., cold extremities, low urine output, altered mentation)
Recurrent HF decompensation
LBBB
Atrial fibrillation
Biomarkers Elevated BNP
Hyponatremia
BUN and creatinine (cardiorenal syndrome)
AST, ALT, and PT (liver dysfunction)
Echocardiographic predictors Low LVEF
LV remodeling (large ESV, EDV)
LV mass
Enlarged LA (LA volume)
Diastolic dysfunction
Dyssynchrony
Pulmonary hypertension
RV dysfunction
Severe MR
Severe TR
Myocardial ischemia and viability
ALT, Alanine aminotransferase; AST, aspartate aminotransferase; BNP, brain natriuretic peptide; BUN, blood urea nitrogen; EDV, end-diastolic volume; ESV, end-systolic volume; HF, heart failure; LA, left atrial; LBBB, left bundle branch block; LV, left ventricular; LVEF, left ventricular ejection fraction; MR, mitral regurgitation; NYHA, New York Heart Association; PT, prothrombin time; RV, right ventricular; TR, tricuspid regurgitation; VO 2 max, maximal oxygen uptake.

The role of cardiac imaging modalities, particularly echocardiography, has been expanding over the past decade. Historically used solely to diagnose cardiomyopathies and assess their severity, echocardiography’s role in early detection, prevention, and prognostication is now well established. The importance of a comprehensive echocardiographic evaluation to understand the underlying cause of the dilated cardiomyopathy (DCM; valvular, ischemic, idiopathic) cannot be overemphasized and certainly plays a role in estimating patient’s prognosis. This chapter focuses on the specific variables linked to prognostic assessment. Details on echocardiographic findings for specific causes can be found in different sections of this book.

Left Ventricular Ejection Fraction and Dimensions

Left ventricular ejection fraction (LVEF) is the most powerful predictor of death and cardiovascular events in patients with DCM. Quinones and colleagues demonstrated in the SOLVD trial that the mortality rate at 1 year was higher in those with LVEF below 35% ( Fig. 67.1 ), a finding that has consistently been verified in the literature. Although multiple thresholds have been evaluated, the overall concept is that prognosis worsens as LVEF decreases, even within patients with severe left ventricular (LV) dysfunction. This finding holds true despite the method of evaluation of LVEF, including two-dimensional (2D) biplane Simpson’s method of disks ( Fig. 67.2 ) and three-dimensional echocardiography ( Fig. 67.3 ). ,

Figure 67.1, All-cause mortality according to left ventricular ejection fraction (LVEF) in the Studies of Left Ventricular Dysfunction (SOLVD) trial. (Reproduced with permission from Quinones MA, et al: Echocardiographic predictors of clinical outcome in patients with left ventricular dysfunction enrolled in the SOLVD registry and trials: significance of left ventricular hypertrophy, J Am Coll Cardiol . 35:1237–1244, 2000.)

Figure 67.2, Left ventricular volumes and ejection fraction evaluation by biplane method of disks. Manual tracing of endocardial border is performed at end-systole ( C and D ) and diastole ( A and B ) in the apical two- and four-chamber views. The method uses calculation of volume of 20 disks of equal thickness to estimate ventricular volumes. The length of the left ventricle is critical for this calculation; therefore, avoiding foreshortening of the left ventricle becomes critical for its accuracy.

Figure 67.3, The advantage of this method over two-dimensional method of disks is that avoids foreshortening and that it uses an automated border detection that improves reproducibility.

LV mass has predictive value independent from other clinical variables and is additive to LVEF. In the Studies of Left Ventricular Dysfunction (SOLVD) trial and registry, patients with LVEF below 35% and LV mass greater than 298 g had the highest mortality rate. Similarly, patients with larger end-systolic and end-diastolic volumes are at higher risks of death and cardiovascular events. However, given the close relationship with LVEF, its independent value is more difficult to prove. Reverse LV remodeling (defined as an increase in LVEF or decrease in LV diastolic dimensions) resulting from optimal medical therapy in patients with DCM has shown to predict better outcomes (specifically mortality and need for heart transplantation).

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