Relative Apical Sparing of Longitudinal Strain Using Two-Dimensional Speckle-Tracking Echocardiography Is Both Sensitive and Specific for the Diagnosis of Cardiac Amyloidosis
Can regional patterns of longitudinal strain (LS) identify individuals with cardiac amyloidosis (CA)?
This study retrospectively evaluated 55 consecutive individuals with CA and 30 controls with left ventricular hypertrophy (LVH), with the latter including 15 with hypertrophic cardiomyopathy and 15 with aortic stenosis. Patterns of LS were compared between groups using absolute comparisons and a relative comparison of apical to nonapical LS [mean apical LS/(mean basal LS + mean mid LS)].
Between individuals with CA and LVH, there was no difference in male gender (85% vs. 70%, p = 0.16), but there was a difference in mean age (68 ± 10 vs. 61 ± 16 years, p = 0.04). Patients with CA (vs. LVH) had differences in mean LV ejection fraction (47 ± 12 vs. 55 ± 13%, p < 0.01), and global LS (-8.9 ± 3.7 vs. -14.9 ± 4.4, p < 0.01). Using mixed model analysis, patients with CA had lower absolute global LS than patients with LVH (p < 0.001). The relative measure of apical LS was significantly increased in CA as compared to controls with LVH (p < 0.001). Using an optimal cutoff of 1.0 from the receiver operator curve analysis, the sensitivity and specificity to differentiate CA from LVH were 93% and 82%, respectively, with an area under the curve of 0.94. Using multivariable analysis, only relative apical LS was independently associated with CA (p = 0.004).
A LS pattern with relative sparing of the apex may be useful to differentiate patients with CA from individuals with LVH due to aortic stenosis or hypertrophic cardiomyopathy.
Identification of CA can often be challenging, and there is a need for improved noninvasive methods to identify this disease. This study reports that a LS pattern with relative sparing of the apex may represent a promising method to separate patients with CA from those with LVH due to aortic stenosis or hypertrophic cardiomyopathy. Future prospective studies in a population with suspected CA are needed to validate these findings.
Keywords: Cardiomegaly, Heart Diseases, Hypertrophy, Left Ventricular, Cardiomyopathies, Cardiomyopathy, Hypertrophic, Heart Failure
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