Transthyretin (TTR) amyloid cardiomyopathy (ATTR-CM) is a progressive disease that has emerged as a significant cause of heart failure. Advances in the understanding of ATTR-CM pathophysiology have revolutionised its therapeutic landscape over the past decade, with the development of targeted therapies that are able to improve survival and quality of life. TTR stabilizers, such as tafamidis and acoramidis, can reduce TTR instability and subsequent amyloid fibril formation. Clinical trials have demonstrated their efficacy both in improving survival and quality of life in patients with ATTR-CM. Gene-silencing therapies using small interfering RNAs (siRNAs), such as patisiran and vutrisiran, or antisense oligonucleotide inhibitors (ASOs), such as inotersen and eplontersen, serve as powerful therapeutic options by decreasing TTR production; trials on patients with ATTR-CM have been recently published or are ongoing. Novel, emerging therapies aim to enhance fibril clearance using monoclonal antibodies, such as NI006, that target amyloid deposits in the myocardium, promoting their depletion, plausibly with regression of the structural and functional impairments caused by the disease. Concurrently, advancements in diagnostic modalities have facilitated earlier detection of this disease, allowing the timely initiation of treatment with a more significant impact on patients’ survival and quality of life. Despite these strides, challenges remain, including the high cost of disease-modifying therapy and the need for response criteria to monitor treatment’s efficacy. Future directions will involve improving patients’ screening to achieve earlier diagnoses, optimising patients’ selection for disease-modifying therapy and identifying criteria for the treatment’s response or lack thereof to possibly consider therapy switch or associations. In this review, we will explore the more recent therapeutic advancements in ATTR-CM, starting from traditional heart failure therapies and moving to disease-modifying therapies with a detailed evaluation of the registration trials to explore the strengths and shortcomings of each treatment.
BACKGROUND: Thresholds to define prognosis with hs-cTnI (high-sensitivity cardiac troponin I) have not been systematically addressed in wild-type transthyretin amyloid cardiomyopathy, in part because of the multiplicity of hs-cTnI assays. The aims of this study were: first, to assess the prognostic performance of hs-cTnI measured with different assays in patients with wild-type transthyretin amyloid cardiomyopathy and, second, to identify assay-specific hs-cTnI thresholds for prognosis that could be integrated into staging systems for risk stratification. METHODS: Observational multicenter study of stable wild-type transthyretin amyloid cardiomyopathy patients from different cohorts using the Abbott Architect Stat hs-cTnI assay and the Beckman Coulter Access hs-cTnI assay (testing cohorts) and the Siemens Centaur XPT hs-cTnI assay (validation cohort). Outcome was all-cause mortality. RESULTS: In the Abbott cohort (n=136; median follow-up 22 [13–41] months; 31 [23%] deaths) and Beckman cohort (n=98; median follow-up 19 [12–28] months; 16 [16%] deaths), natural log-transformed hs-cTnI was an independent predictor of mortality (age- and sex-adjusted hazard ratio, 1.62 [95% CI, 1.11–2.35]; P =0.012 and 2.47 [95% CI, 1.48–4.14]; P 80 ng/L) and NPs (natriuretic peptides; NT-proBNP [N-terminal pro-B-type natriuretic peptide] >3000 ng/L or BNP [B-type natriuretic peptide] >250 ng/L) identified 3 groups with progressively worse prognosis. The staging system (using hs-cTnI >80 ng/L and NT-proBNP>3000 ng/L) was then applied to an independent cohort evaluated with the hs-cTnI Siemens assay (n=345, median follow-up 32 [24-42] months, 119 [34%] deaths). The significant differences between the groups were maintained. CONCLUSIONS: In patients with wild-type transthyretin amyloid cardiomyopathy, hs-cTnI is a strong and independent predictor of mortality. A threshold of hs-cTnI of 80 ng/L for these 3 assays provides effective risk stratification alone and in a staging system with NP.