More Strain equals better accuracy? The use of various strain indices to differentiate Cardiac amyloidosis and Fabry disease

T. Steudel (Berlin)¹, G. Barzen (Berlin)², D. Frumkin (Berlin)³, E. Romero Dorta (Berlin)⁴, S. Spethmann (Berlin)⁵, G. Hindricks (Berlin)⁴, K. Stangl (Berlin)⁶, F. Knebel (Berlin)⁷, B. Heidecker (Berlin)⁸, S. Canaan-Kühl (Berlin)⁹, H. F. Pernice (Berlin)¹⁰, K. Hahn (Berlin)¹¹, I. Mattig (Berlin)⁴, A. M. Brand (Berlin)^8
1Deutsches Herzzentrum der Charité (DHZC) Klinik für Kardiologie, Angiologie und Intensivmedizin Berlin, Deutschland; ²Amyloidosis Center Charité Berlin (ACCB), Deutsches Herzzentrum der Charité, Charité - Universitätsmedizin Berlin Klinik für Kardiologie, Angiologie und Intensivmedizin Berlin, Deutschland; ³Deutsches Herzzentrum der Charite (DHZC) Berlin, Deutschland; ⁴Charité - Universitätsmedizin Berlin CC11: Med. Klinik m. S. Kardiologie und Angiologie Berlin, Deutschland; ⁵Charité - Universitätsmedizin Berlin Klinik für Kardiologie, Angiologie und Intensivmedizin Berlin, Deutschland; ⁶DHZC- Deutsches Herzzentrum der Charite Berlin Klinik für Kardiologie, Angiologie und Intensivmedizin, Campus Mitte Berlin, Deutschland; ⁷Sana Klinikum Lichtenberg Klinik für Innere Medizin II, Schwerpunkt Kardiologie Berlin, Deutschland; ⁸Charité - Universitätsmedizin Berlin CC 11: Med. Klinik für Kardiologie Berlin, Deutschland; ⁹Charité - Universitätsmedizin Berlin Nephrologie Berlin, Deutschland; ¹⁰Charité - Universitätsmedizin Berlin Klinik für Neurologie mit Experimenteller Neurologie Berlin, Deutschland; ¹¹Klinik für Neurologie Amyloidosis Center Charite Berlin Berlin, Deutschland

Background:
The discrimination of infiltrative cardiomyopathies or storage diseases such as Cardiac amyloidosis (CA) or Fabry disease (FD) remains challenging even when using strain derived LV parameters. The aim of this study was to improve the diagnostic accuracy by testing layer-specific strain and atrial strain measurements in addition to established disease specific LV longitudinal strain patterns.

Methods:
In a retrospective approach, we analyzed global and regional LV longitudinal strain patterns, LV radial layer strain as well as RA and LA strain indices in 76 patients with CA and 41 patients with FD. A Receiver operating curve (ROC) was performed to assess the diagnostic accuracy.

Results:
Patients in the CA group were older, predominantly men (80%) and had more comorbidities. They showed an overall further advanced cardiomyopathy compared to the FD group resulting in overall more deteriorated strain values. Global longitudinal and radial strain showed a good performance (AUC) [0.73 (CI 0.63 to 0.83) for GLS and 0.75 (CI 0.66 to 0.84) for GRS]. However, the established specific longitudinal strain patterns “apical sparing” and “posterolateral strain deficiency” remained superior to discriminate CA [AUC 0.87 (CI 0.79 to 0.95) for AS and 0.81(CI 0.72 to 0.89) for PLSD, p<0.001]. Measuring atrial strain patterns, left and right atrial reservoir strain showed an excellent diagnostic value to discriminate CA [LASr AUC 0.88 (CI 0.81 to 0.92) and RASr AUC 0.89 (CI 0.83 to 0.97)].

Conclusion:
Specific regional LV strain patterns and atrial mechanics feature a very high diagnostic accuracy to discriminate CA and FD in suspected storage disease.