Utility of left atrial and ventricular strain for diagnosis of transthyretin amyloid cardiomyopathy in aortic stenosis.

Aims: To clarify the usefulness of left atrial (LA) function and left ventricular (LV) function obtained by two-dimensional (2D) speckle tracking echocardiography to diagnose concomitant transthyretin amyloid cardiomyopathy (ATTR-CM) in patients with aortic stenosis (AS).

Methods And Results: We analysed 72 consecutive patients with moderate to severe AS who underwent Tc-pyrophosphate (PYP) scintigraphy at Kumamoto University Hospital from January 2012 to September 2020. We divided these 72 patients into 2 groups based on their Tc-PYP scintigraphy positivity or negativity. Among 72 patients, 16 patients (22%) were positive, and 56 patients (78%) were negative for Tc-PYP scintigraphy. In clinical baseline characteristics, natural logarithm troponin T was significantly higher in the Tc-PYP scintigraphy-positive than scintigraphy-negative group (-2.9 ± 0.5 vs. -3.5 ± 0.8 ng/mL, P < 0.05). In conventional echocardiography, the severity of AS was not significantly different between these two groups. In 2D speckle tracking echocardiography, the relative apical longitudinal strain (LS) index (RapLSI) [apical LS/ (basal LS + mid LS)] was significantly higher (1.09 ± 0.49 vs. 0.78 ± 0.23, P < 0.05) and the peak longitudinal strain rate (LSR) in LA was significantly lower in the Tc-PYP scintigraphy-positive than scintigraphy-negative group (0.36 ± 0.14 vs. 0.55 ± 0.20 s , P < 0.05). Multivariable logistic analysis revealed the peak LSR in LA and RapLSI were significantly associated with Tc-PYP scintigraphy positivity. Receiver operating characteristic analysis showed that the area under the curve (AUC) of the peak LSR in LA for Tc-PYP scintigraphy positivity was 0.79 and that the best cut-off value of the peak LSR in LA was 0.47 s (sensitivity: 78.6% and specificity: 72.3%). The AUC of RapLSI for Tc-PYP scintigraphy positivity was 0.69, and the cut-off value of RapLSI was decided as 1.00 (sensitivity: 43.8% and specificity: 87.5%) according to the previous report. The Tc-PYP scintigraphy positivity in patients with RapLSI ≥ 1.0 and the peak LSR in LA ≤ 0.47 s was 83.3% (5/6), and the Tc-PYP scintigraphy negativity in patients with RapLSI < 1.0 and the peak LSR in LA > 0.47 s was 96.6% (28/29).

Conclusions: Left atrial and LV strain analysis were significantly associated with Tc-PYP scintigraphy positivity in ATTR-CM patients with moderate to severe AS. The combination of the peak LSR in LA and RapLSI might be a useful predictor of the presence of ATTR-CM in patients with moderate to severe AS.