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Echo Diastolic Stress Test for Dyspnea
Study Questions:
Among dyspneic patients with mild left ventricular (LV) diastolic dysfunction, can clinical, biochemical, and resting echocardiographic markers predict an abnormal diastolic response to exercise?
Methods:
In 171 dyspneic patients (64 ± 8 years) with suspected heart failure with preserved ejection fraction (HFpEF) but resting peak early diastolic mitral inflow velocity/peak early diastolic mitral annular velocity ratio (E/e’) <14, a complete echocardiogram (including assessment of myocardial deformation and rotational mechanics) and blood assays for biomarkers were performed. Echocardiography following maximal exercise was undertaken to assess an abnormal diastolic response to exercise (exertional E/e’ >14). Patients were followed over 26.2 ± 4.6 months for endpoints of cardiovascular hospitalization and death.
Results:
An abnormal diastolic response to exercise was present in 103 subjects (60%). Independent correlates of an abnormal diastolic response to exercise were resting E/e’ (odds ratio [OR], 8.23; 95% confidence interval [CI], 3.54-9.16; p < 0.001); LV untwisting rate (OR, 0.60; 95% CI, 0.42-0.86; p = 0.006); and galectin-3, a marker of fibrosis (OR, 1.80; 95% CI, 1.21-2.67; p = 0.004). The use of resting E/e’ >11.3 and galectin-3 <1.17 ng/ml to select patients for further diagnostic processing would have allowed exercise testing to be avoided in 65% of subjects, at the cost of misclassification of 13%. The composite outcome of cardiovascular hospitalization or death occurred in 47 patients (27.5%). The predictive value of an abnormal diastolic response to exercise and the combined strategy (resting echocardiography and galectin-3 or exercise testing in case of an inconclusive first step) showed similar event prediction (36 vs. 34; p = 0.95).
Conclusions:
The authors concluded that the implementation of a two-step algorithm (echocardiographic evaluation of resting E/e’ followed by the assessment of galectin-3) may improve the diagnosis and prognostic assessment of individuals with suspected HFpEF who are unable to perform a diagnostic exercise test.
Perspective:
Among patients with symptoms of dyspnea, an abnormal diastolic response to exercise (mitral E/e’ >14, indicative of exercise-associated increase in LV filling pressure) may support a diagnosis of HFpEF despite resting echo/Doppler parameters that do not suggest advanced LV diastolic dysfunction (E/e’ <14). However, physical constraints can limit the ability to perform exercise testing. This study suggests that resting E/e’ >11.3 and blood galectin-3 <1.17 ng/ml could be useful surrogates for exercise echocardiography in the assessment of possible HFpEF as a cause of dyspnea. If these findings can be validated in other patient cohorts, the assessment of resting mitral E/e’ and blood galectin-3 could serve as diagnostic markers of HFpEF among patients with dyspnea.
Keywords: Biomarkers, Diagnostic Imaging, Diastole, Dyspnea, Echocardiography, Exercise Test, Galectin 3, Heart Failure, Stroke Volume, Ventricular Dysfunction, Left
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