Background: There are good data to support using a single high-sensitivity cardiac troponin T (hs-cTnT) below the limit of detection of 5 ng/L to exclude acute myocardial infarction. Per the US Food and Drug Administration, hs-cTnT can only report to the limit of quantitation of 6 ng/L, a threshold for which there are limited data. Our goal was to determine whether a single hs-cTnT below the limit of quantitation of 6 ng/L is a safe strategy to identify patients at low risk for acute myocardial injury and infarction. Methods: The efficacy (proportion identified as low risk based on baseline hs-cTnT<6 ng/L) of identifying low-risk patients was examined in a multicenter (n=22 sites) US cohort study of emergency department patients undergoing at least 1 hs-cTnT (CV Data Mart Biomarker cohort). We then determined the performance of a single hs-cTnT99th percentile in those with an initial hs-cTnT<6 ng/L). The clinically intended rule-out strategy combining a nonischemic ECG with a baseline hs-cTnT<6 ng/L was subsequently tested in an adjudicated cohort in which the diagnostic performance for ruling out acute myocardial infarction and safety (myocardial infarction or death at 30 days) were evaluated. Results: A total of 85 610 patients were evaluated in the CV Data Mart Biomarker cohort, among which 24 646 (29%) had a baseline hs-cTnT<6 ng/L. Women were more likely than men to have hs-cTnT<6 ng/L (38% versus 20%, P <0.0001). Among 11 962 patients with baseline hs-cTnT<6 ng/L and serial measurements, only 1.2% developed acute myocardial injury, resulting in a negative predictive value of 98.8% (95% CI, 98.6–99.0) and sensitivity of 99.6% (95% CI, 99.5–99.6). In the adjudicated cohort, a nonischemic ECG with hs-cTnT<6 ng/L identified 33% of patients (610/1849) as low risk and resulted in a negative predictive value and sensitivity of 100% and a 30-day rate of 0.2% for myocardial infarction or death. Conclusions: A single hs-cTnT below the limit of quantitation of 6 ng/L is a safe and rapid method to identify a substantial number of patients at very low risk for acute myocardial injury and infarction.

Aims: Myocardial longitudinal strain (LS) by two-dimensional (2D) speckle-tracking echocardiography has a diagnostic and prognostic role in cardiac amyloidosis (CA). Typically, the apical segments of the left ventricle (LV) are less affected by LS abnormalities, a finding called relative apical sparing (RELAPS). Whether a variable burden of CA might explain the RELAPS remains unknown. We aimed to evaluate the extent, distribution, and deposition pattern of amyloid in autopsy hearts of CA patients and to correlate the histopathology findings with 2D echocardiography. Methods and results: This is a retrospective study of whole heart specimens of CA patients who died and underwent autopsy and 2D echocardiography. Amyloid burden quantification was assessed by histomorphometry in each segment at different LV levels. The LS analysis results were compared with the amyloid burden and the base-to-apex distribution. Histopathology investigation of 27 hearts with CA [immunoglobulin light chains (AL) 17 cases and transthyretin (ATTR) 10 cases] demonstrated an amyloid base-to-apex gradient. In 11 CA patients with 2D echocardiography, analysis of LS and histological amyloid burden allowed to identify different patterns: RELAPS (8 cases, 73%), with (2) or without (6) amyloid gradient, normal or mildly reduced LS with diffuse low amyloid (2, 18%), and severely reduced LS with diffuse high amyloid (1, 9%). Conclusion: The typical RELAPS pattern at echocardiography is not always explained by a base-to-apex gradient of amyloid burden at histopathology, suggesting that RELAPS might be an epiphenomenon of complex interactions among amyloid infiltration, myocardial structure, and adaptation.

Transthyretin amyloidosis (ATTR) is a group of diseases caused by the deposition of insoluble fibrils derived from misfolded transthyretin, which compromises the structure and function of various organs, including the heart. Thromboembolic events and increased bleeding risk are among the most important complications of ATTR, though the underlying mechanisms are not yet fully understood. Transthyretin plays a complex role in the coagulation cascade, contributing to the activation and regulation of the coagulation and fibrinolytic systems. The prevalence of atrial fibrillation, cardiac mechanical dysfunction, and atrial myopathy in patients with ATTR may contribute to thrombosis, though such events may also occur in patients with a normal sinus rhythm and rarely in properly anticoagulated patients. Haemorrhagic events are modest and mainly linked to perivascular amyloid deposits with consequent capillary fragility and coagulation anomalies, such as labile international-normalised ratio during anticoagulant therapy. Therefore, it is paramount to carefully stratify the thrombotic and haemorrhagic risks, especially when initiating anticoagulant therapy. Our review aims to ascertain the prevalence of thromboembolic and haemorrhagic events in ATTR and identify potential risk factors and predictors and their impact on antithrombotic therapy.

Aims: Hereditary transthyretin amyloidosis (ATTRv) is a rare, heterogeneous, inherited disorder caused by over 130 gene mutations. Its prevalence was estimated to 4.33/million in 2020 in Italy. Whether growing disease awareness and improved diagnostics may have increased national diagnoses in the last 4 years is unresolved. Methods and results: All alive ATTRv diagnoses from 2004 to 2024 from 16 Italian referral centres were retrospectively assessed and included in the analysis. As of March 2024, 373 ATTRv patients were in active follow-up, with an overall national prevalence increased from 2020 previous survey up to 6.33/million. The most prevalent mutations were Ile68Leu (25.1%), Phe64Leu (21.9%), Val30Met (19.3%), Glu89Gln (10.7%), and Val122Ile (6.7%). Ile68Leu, Val122Ile, and Val30Met were more common in Northern and Central Italy, while Glu89Gln and Phe64Leu were prevalent in Southern Italy. Cardiovascular phenotype was the most common (35.6%), followed by neuropathic (33.2%) and mixed phenotypes (31.2%). Referral to disease-specific therapy mirrored the change in epidemiology. Conclusion: ATTRv prevalence in Italy has increased by 50% in a 4 years’ time frame, with a shift towards milder disease stages and more mixed phenotypes. These changes may reflect improved disease awareness, enhanced genetic screening, and comprehensive care in specialized centres.

Diagnosing myocardial infarction (MI) in patients with chronic kidney disease (CKD) is difficult as they often have increased high-sensitivity cardiac troponin T (hs-cTnT) concentrations. Observational U.S. cohort study of emergency department (ED) patients undergoing hs-cTnT measurement. Cases with >1 hs-cTnT increase >99^th percentile were adjudicated following the Fourth Universal Definition of MI. Diagnostic performance of baseline and serial 2-hour hs-cTnT thresholds for ruling-in acute MI was compared between those without and with CKD (eGFR <60 ml/min/1.73m²). The study cohort included 1992 patients, amongst whom 501 (25%) had CKD. There were 75 (15%) and 350 (70%) patients with CKD and 80 (5%) and 351 (24%) without CKD who had acute MI and myocardial injury. In CKD patients with baseline hs-cTnT thresholds of >52, >100, >200 or >300 ng/L, PPVs for MI were 36% (95% CI 28-45), 53% (95% CI 39-67), 73% (95% CI 50-89) and 80% (95% CI 44-98), and in those without CKD, 61% (95% CI 47-73), 69% (95% CI 49-85), 59% (95% CI 33-82) and 54% (95% CI 25-81). In CKD patients with a 2-hour hs-cTnT delta of >10, >20 or >30 ng/L, PPVs were 66% (95% CI 51-79), 86% (95% CI 68-96) and 88% (95% CI 68-97), and in those without CKD, 64% (95% CI 50-76), 73% (95% CI 57-86) and 75% (95% CI 58-88). Diagnostic performance of standard baseline and serial 2-hour hs-cTnT thresholds to rule-in MI is suboptimal in CKD patients. It significantly improves when using higher baseline thresholds and delta values.

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.