Prognostic value of cardio-pulmonary exercise testing in cardiac amyloidosis.

Nicol M; Deney A; Lairez O; Vergaro G; Emdin M;Inamo J; Montfort A; Neviere R; Damy T; Harel S;Royer B; Baudet M; Cohen-Solal A; Arnulf B;Logeart D;

European journal of heart failure [Eur J Heart Fail] 2020 Oct 02. Date of Electronic Publication: 2020 Oct 02.

Background: In amyloid patients, cardiac involvement dramatically worsens functional capacity and prognosis.
Purpose: We sought to study how the cardio-pulmonary exercise test (CPET) could help in functional assessment and risk stratification of patients with cardiac amyloidosis (CA).
Methods: We carried out a multicenter study including patients with light chain (AL) or transthyretin (TTR) CA. All patients underwent exhaustive examination including CPET and follow-up. The primary prognostic endpoint was the occurrence of death or heart failure (HF) hospitalization.
Results: We included 150 patients: 91 AL and 59 TTR CA. Median age, systolic blood pressure, NT-proBNP and cardiac troponin T were 70 [64-78] years old, 121 [IQR 109-139] mmHg, 2809 [IQR 1218-4638] ng/L and 64 [IQR 33-120] ng/L respectively. NYHA classes were I- II in 64%. Median peak VO 2 and circulatory power were low at 13.0 mL/kg/min [10.0-16.9] and 1729 mmHg.mL -1 min _1 [1318-2614] respectively. The VE/VCO 2 slope was increased to 37 [IQR 33-45]. Seventy-seven patients (51%) had chronotropic insufficiency. After a median follow-up of 20 months, there were 37 deaths and 44 HF hospitalizations. Multivariate Cox analysis shows that peak VO 2  ≤ 13 mL/kg/min (HR 2.7; CI95% 1.6-4.8), circulatory power ≤ 1800 mmHg.mL.min -1 (HR 2.4; CI95% 1.2-4.6) and NT-proBNP ≥1800 ng/L (HR 2.2; CI95% 1.1-4.3) were associated with the primary outcome. There was no event in patients with both peak VO2 > 13 mL/kg/min and NTproBNP <1800 ng/L, while the association of VO2 ≤ 13 mL/kg/min and NTproBNP ≥1800 ng/L identified a very high-risk subgroup.
Conclusion: In CA, CPET helps to assess functional capacity, circulatory and chronotropic responses and helps to assess the prognosis of patients along with cardiac biomarkers.