Diagnostic value of papillary muscle hypertrophy and mitral valve thickness to discriminate cardiac amyloidosis and Fabry disease.

BACKGROUND: Cardiac amyloidosis (CA) and Fabry disease (FD) cause myocardial damage but may also affect the valvular and subvalvular apparatus. We aimed to evaluate the diagnostic accuracy of new echocardiographic indices including mitral valve thickness and papillary muscle (PM) hypertrophy to differentiate CA and FD. METHODS: In patients with confirmed CA and FD, a detailed assessment of valvular function, mitral valve leaflet thickness and PM area as well as PM left ventricular area ratio (PM/LV-ratio) was performed in offline analyses. Receiver operating characteristic curve analyses were conducted to determine the diagnostic accuracy of mitral valve thickness, PM hypertrophy, and PM/LV-ratio to distinguish CA from FD. RESULTS: We retrospectively analyzed a cohort of 129 patients (FD n = 49, CA n = 80). CA patients showed significantly more thickened mitral valve leaflets (4.1 ± 1.3 mm vs. 2.9 ± 1.1 mm, p < 0.001) and a higher PM area [4.0 (3.1-4.6) mm2 vs. 2.8 (2.1-4.6) mm2, p = 0.009] with a comparable PM/LV-ratio in both groups. Mitral valve thickness showed the highest diagnostic accuracy to discriminate CA [AUC 0.77 (95% CI 0.67-0.87)]. The prevalence of aortic, tricuspid, and pulmonary valve regurgitation was significantly higher in CA (aortic regurgitation ≥ II° 13% vs. 4%, tricuspid regurgitation≥ II° 19% vs. 8%, p < 0.001). CONCLUSION: Our results suggest that the assessment of mitral valve thickness may be a new useful echocardiographic parameter to differentiate CA and FD, whereas papillary muscle hypertrophy and PM/LV-ratio showed a limited diagnostic performance to discriminate CA. German clinical trials registry: DRKS00027403.

Diagnostic value of left ventricular layer strain and specific regional strain patterns in cardiac amyloidosis and Fabry disease.

Aims: Layer-specific left ventricular (LV) strain alterations have been suggested as a specific finding in Fabry disease (FD). Our study aimed to assess the diagnostic value of layer-specific radial strain (RS) indices compared to the established LV regional strain pattern in cardiac amyloidosis (CA) and FD, i.e. apical sparing and posterolateral strain deficiency (PLSD). Methods and results: We retrospectively analysed the global, subendocardial, subepicardial LV radial strain, the corresponding strain gradient, as well as the regional and global longitudinal strain. The diagnostic accuracy of the diverse LV strain analyses was comparatively assessed using receiver operating characteristic curve and multivariable regression analyses. In 40 FD and 76 CA patients, CA featured more reduced layer strain values [global RS -12.3 (-15.6 to -9.6) in CA vs. -16.7 (-20.0 to -13.6) in FD; P < 0.001; subendocardial RS -22.3 (-27.4 to -15.9) vs. -28.3 (-31.8 to -23.6), P < 0.001; subepicardial RS -6.6 (-8.6 to -4.7) in CA vs. -8.9 (-11.7 to - 6.5) in FD; P < 0.001]. Global radial and longitudinal strain held an area under the curve (AUC) of 0.75 (0.66-0.84) and AUC 0.73 (0.63-0.83). While the apical sparing and PLSD strain pattern showed the highest accuracy as single parameters [AUC 0.87 (0.79-0.95) and 0.81 (0.72-0.89), P < 0.001], the combination of subendocardial RS and the apical sparing pattern featured the highest diagnostic accuracy [AUC 0.92 (0.87-0.97)]. Conclusion: Combining radial strain-derived parameters to the established strain pattern apical sparing and PLSD improve the diagnostic accuracy in the echocardiographic assessment in suspected storage disease.

Right heart and left atrial strain to differentiate cardiac amyloidosis and Fabry disease.

Echocardiographic differentiation of cardiac amyloidosis (CA) and Fabry disease (FD) is often challenging using standard echocardiographic parameters. We retrospectively analyzed the diagnostic accuracy of right heart and left atrial strain parameters to discriminate CA from FD using receiver operating characteristic curve analyses and logistic regression models. A total of 47 FD and 88 CA patients with left ventricular wall thickening were analyzed. The comparison of both cardiomyopathies revealed significantly reduced global and free wall longitudinal right ventricular strain (RVS; global RVS: CA - 13 ± 4%, n = 67, vs. FD - 18 ± 4%, n = 39, p < 0.001) as well as right atrial strain (RAS; reservoir RAS: CA 12 ± 8%, n = 70, vs. FD 26 ± 9%, n = 40, p < 0.001) and left atrial strain (LAS) in CA patients. Individually, global RVS as well as phasic LAS and RAS showed the highest diagnostic accuracy to distinguish CA and FD. The best diagnostic accuracy was achieved by combining the age, basal RV diameter, global RVS, and reservoir and conduit RAS (area under the curve 0.96 [95% CI 0.90-1.00]). Differential echocardiographic diagnostic work-up of patients with suspected CA or FD can be improved by integrating structural and functional parameters of the right heart and the left atrium.Trial registration: DRKS00027403.