Transthyretin amyloid cardiomyopathy (ATTR-CM) is increasingly diagnosed at an early stage of the disease natural history, defined as National Amyloidosis Centre (NAC) ATTR Stage I. The natural history of early-stage ATTR-CM remains poorly characterized. A retrospective multi-centre observational study of 879 patients with ATTR-CM, either wild-type TTR genotype or carrying the p.V142I TTR variant, and NAC ATTR Stage I biomarkers at the time of diagnosis who did not receive disease-modifying therapy for amyloidosis. Disease characteristics at diagnosis that were independently associated with mortality by Cox regression analysis were N-terminal pro-B-type natriuretic peptide (NT-proBNP), TTR genotype, and troponin T. Patients were categorized into NAC ATTR Stage Ia, defined as a furosemide equivalent diuretic requirement of 100 months in the 12% with Stage Ia disease [hazard ratio for death 5.06 (95% confidence interval 1.23–20.87); P = 0.025] despite significant cardiovascular morbidity at the time of diagnosis which increased during follow-up, including among patients diagnosed in NAC ATTR Stage Ia. Estimated survival among UK NAC ATTR Stage Ia patients was comparable to UK general population controls (P = 0.297). Patients with NAC ATTR Stage I ATTR-CM can be further stratified according to NT-proBNP concentration and diuretic requirement at diagnosis. Patients with Stage Ia ATTR-CM have significant cardiovascular morbidity despite good short- and mid-term survival. Patients diagnosed with NAC ATTR Stage Ia amyloidosis have an estimated median survival in excess of 100 months in the absence of disease-modifying therapy despite significant cardiovascular morbidity which increases further during follow up.

Background: We assesse the evolution and prognostic value of N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitivity troponin T (cTnT-HS) in transthyretin amyloid cardiomyopathy (ATTR-CA) before and after tafamidis treatment. Methods and Results: 454 ATTR-CA patients without tafamidis (Cohort A) and 248 ATTR-CA with tafamidis (Cohort B) were enrolled. Event-free survival (EFS) events were death, heart transplant, or acute heart failure. In Cohort A, 27% of patients maintained NT-proBNP < 3000 ng/L and 14% cTnT-HS < 50 ng/L at 12 months relative to baseline levels. In Cohort B, the proportions were 49% and 29%, respectively. In Cohort A, among the 333 patients without an increased NT-proBNP > 50% relative to baseline EFS was extended compared to the 121 patients with an increased NT-proBNP > 50% (HR: 0.75 [0.57; 0.98]; p = 0.032). In Cohort A, baseline NT-proBNP > 3000 ng/L and cTnT-HS > 50 ng/L and a relative increase of NT-proBNP > 50% during follow-up were independent prognostic factors of EFS. The slopes of logs NT-proBNP and cTnT-HS increased with time before and stabilized after tafamidis. Conclusion: ATTR-CA patients with increasing NT-proBNP had an increased risk of EFS. Tafamidis stabilize NT-proBNP and cTnT-HS increasing, even if initial NT-proBNP levels were >3000 ng/L. Thus suggesting that all patients, irrespective of baseline NT-proBNP levels, may benefit from tafamidis.

Background: Cardiac light chain amyloidosis (AL-CA) patients often die within three months of starting chemotherapy. Chemotherapy for non-immunoglobulin M gammopathy with AL-CA frequently includes bortezomib (Bor), cyclophosphamide (Cy), and dexamethasone (D). We previously reported that NT-ProBNP levels can double within 24h of dexamethasone administration, suggesting a deleterious impact on cardiac function. In this study, we evaluate the role of dexamethasone in early cardiovascular mortality during treatment. Methods and findings: We retrospectively assessed 100 de novo cardiac AL patients (62% male, mean age 68 years) treated at our institute between 2009 and 2018 following three chemotherapy regimens: CyBorDComb (all initiated on day 1; 34 patients), DCyBorSeq (D, day 1; Cy, day 8; Bor, day 15; 17 patients), and CyBorDSeq (Cy, day 1; Bor, day 8; D, day 15; 49 patients). The primary endpoint was cardiovascular mortality and cardiac transplantation at days 22 and 455. At day 22, mortality was 20.6% with CyBorDComb, 23.5% with DCyBorSeq, and 0% with CyBorDSeq (p = 0.003). At day 455, mortality was not significantly different between regimens (p = 0.195). Acute toxicity of dexamethasone was evaluated on myocardial function using a rat model of isolated perfused heart. Administration of dexamethasone induced a decrease in left ventricular myocardium contractility and relaxation (p<0.05), supporting a potential negative inotropic effect of dexamethasone in AL-CA patients with severe cardiac involvement. Conclusion: Delaying dexamethasone during the first chemotherapy cycle reduces the number of early deaths without extending survival. It is clear that dexamethasone is beneficial in the long-term treatment of patients with AL-CA. However, the initial introduction of dexamethasone during treatment is critical, but may be associated with early cardiac deaths in severe CA. Thus, it is important to consider the dosage and timing of dexamethasone introduction on a patient-severity basis. The impact of dexamethasone in the treatment of AL-CA needs further investigation.

Guidelines recommend screening for transthyretin amyloid cardiomyopathy (ATTR-CM) after age 65 years, yet some patients are diagnosed earlier. The purpose of this study was to compare the proportion, clinical characteristics, and prognosis of wild-type ATTR-CM diagnosed ≤65 years (ATTRwt-Yy) with those diagnosed >65 years (ATTRwt-O). Data from the HEAR (Healthcare European Amyloidosis Registry), a multicenter, noninterventional, longitudinal registry, were analyzed. Patients were categorized by age at diagnosis: ATTRwt-Yy (≤65 years) and ATTRwt-O (>65 years). ATTRwt-O patients were further classified by onset of first cardiac symptom: ATTRwt-Oy (≤65 years) and ATTRwt-Oo (>65 years). From July 2021 to May 2024, 3,980 ATTR patients were enrolled; 1,417 had ATTRwt-CM with documented symptom onset. Among them, 67 (4.7%) were ATTRwt-Yy, 111 (7.8%) ATTRwt-Oy, and 1,239 (87.4%) ATTRwt-Oo. Diagnostic delays were 0.65, 20.58, and 0.77 years, respectively (P < 0.001). Heart failure signs at presentation were seen in 34.9% of ATTRwt-Yy, 8.1% of ATTRwt-Oy, and 30.2% of ATTRwt-Oo (P < 0.001). ATTRwt-Yy patients had more extracardiac manifestations, notably osteoarticular disease, whereas rhythm disturbances predominated in ATTRwt-Oy. Median follow-up from diagnosis was 36.2, 23.6, and 22.4 months, respectively. ATTRwt-Yy patients had better survival after diagnosis compared to ATTRwt-O patients. ATTRwt-CM diagnosed before 65 years shows a distinct phenotype highlighting the need for tailored diagnostic and management strategies.