Relationship between severity of HDP-99mTc myocardial uptake on bone scintigraphy (BS) and severity of cardiac involvement in transthyretine cardiac amyloïdosis (TTR-CA)

Bone scintigraphy (BS) with HDP-99mTc is routinely used to diagnose transthyretine cardiac amyloidosis (TTR-CA), but the interplay between BS and cardiac prognosis parameters is unclear. To evaluate if myocardial uptake (MU) intensity on BS correlates with cardiac electric, echographic and biomarkers abnormalities in patients with TTR-CA. Patients with confirmed TTR-CA underwent complete evaluation including ECG, echocardiography and biomarkers to describe: voltage (SV1 + RV5, in mV), left ventricular mass (LVM, g/m2), interventricular septum thickness (dIVS) and TAPSE (in mm), NT-proBNP and troponine. Patients were classified into 3 categories according to MU on BS with Perugini (P) score: PI (MU < chest bones), PII (MU = chest bones) and PIII (MU > bones). Main end-point was LVM and Voltage/Mass ratio (VMR, μVolts/g/m2). Among the 65 patients included, mean age was 82 ± 8 years and 82% were males. Overall mortality 20%. On BS, 6 patients (9%) were ranked as PI, 28 (43%) PII and 31 (48%) PIII, with no difference on mortality rates. After ANOVA, mean LVM, dIVS (P = 0.001), left atrial volume signicatively raised throughout the 3 categories of PS, whereas VMR and TAPSE were lower (Table 1 and Fig. 1). After Pearson test, PS correlated with LVM (r = +0.48, P = 0.03) and VMR (r = –0.44, P = 0.0004), but also: dIVS (r = +0.43, P = 0.0004), left atrial volume (r = 0.37, P = 0.003), TAPSE (r = –0.32, P = 0.01), NT-proBNP (r = +0.28, P = 0.03) and troponine levels (r = +0.26, P = 0.04). In TTR-CA patients, Perugini score correlates with cardiac mass and voltage and might be a marker of advanced disease. Further studies are needed to confirm these results.