Voltage/mass ratio (VMR) prognosis value in heart failure (HF) patients with transthyretin cardiac amyloidosis (ATTR-CA)

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Transthyretin cardiac amyloidosis (ATTR-CA) is an emerging cause of heart failure (HF) and is associated with cardiac mass hypertrophy and voltage impairment, but little is known on how theses markers interplay with survival. Objective To evaluate if cardiac voltage/mass ratio (VMR) is associated with prognosis in HF patients involving ATTR-CA. Methods Patients with confirmed mutated (m) or wild-type (wt) ATTR-CA addressed in a single cardiology center underwent retrospective ECG and echocardiographic study to define voltage with Sokolow indice (SV1+RV5, in mV) and left ventricular mass (LVM, g/m²) according to ASE definition. Two groups of patients were defined according to the median cardiac voltage/mass ratio (VMR in µV/g/m²) : Low (VMR < 6.1) or normal (VMR ≥ 6.1). Tc99m-HDP myocardial uptake (MU) on bone scintigraphy (BS) was described according to Perugini (P) classification : PI (MU < chest bones), PII (MU = chest bones) and PIII (MU > bones). Main end-point was overall mortality. Results Among the 74 patients included, mean age was 82±7 years, 80% were males (Graph 1) and 25 (34%) were classified as ATTRwt-CA, 3 (4%) as ATTRm-CA, and 46 (62%) had ongoing genetic exploration. Mean follow-up was 543±332 days. Overall mortality was 21%. On BS, 6 patients (8%) were ranked as PI, 30 (42%) PII and 36 (50%) PIII, with no difference on mortality rates. After ANOVA, mean VMRi significantly decreased with intensity of Tc99m-HDP myocardial uptake on BS (p=0.033, Graph 2A). After log-rank test, survival was impaired in the low VMR group (p=0.034, Graph 2B). After Cox regression, low voltage/masse ratio remained associated with increased risk of mortality (HR 4.6, 95% CI [1.1–18.6], p=0.03), after adjusting on age, sex, left ventricle ejection fraction and log(NT-proBNP). Conclusion VMR is a simple index to collect and significantly associated with impaired survival in HF patients with ATTR-CA. Further studies are needed to confirm these results.