In Brief | Rare Diseases | Cardiovascular Diseases
Revealing Cardiac Amyloidosis: A Fresh Perspective on Rare Diseases in Cardiology
Time to read: 03: 23
Time to listen: 08:54
Originally Published: 20 December 2024
Sourced: American Journal of Translational Research
Type of article: In Brief
MedED Catalogue Reference: MIBRR002
Category: Cardiovascular Disease
Cross Reference: Gerontology
Keywords: cardiac amyloidosis, cardiac abnormalities, heart failure, rare diseases
The pathogenesis of cardiac amyloidosis (CA) is unclear, with diverse and non-specific clinical manifestations complicating diagnosis and management. As a result, treatment and prognosis vary widely among different subtypes, emphasising the need for tailored therapies based on specific subtype and etiology to optimise outcomes.
This is a review of original research published in American Journal of Translational Research,15 September 2024. This article does not represent the original research, nor is it intended to replace the original research. Unless otherwise references, all information contained in this review is referenced to the original work. Access the full Disclaimer Information.
Amyloidosis is a rare systemic disease characterized by abnormal protein deposits in various organs, including the heart.
When these deposits infiltrate the myocardium, the condition is termed cardiac amyloidosis (CA), leading to structural and functional cardiac abnormalities, heart failure, and arrhythmias. Despite its significance, CA has been historically underdiagnosed due to limited clinical awareness and diagnostic challenges.The most common subtypes affecting the heart include primary systemic light chain amyloidosis, transthyretin amyloidosis, and secondary amyloidosis.
Early symptoms of CA are often nonspecific, contributing to delayed diagnosis. Many patients are diagnosed at an advanced stage with severe heart failure, where conventional heart failure treatments are largely ineffective, resulting in high mortality rates.
Additionally, CA patients with significant symptoms are often excluded from clinical trials, further limiting understanding and therapeutic advancements. Existing research is mostly based on single-centre case reports, with a lack of comprehensive clinical studies.
This study aimed to enhance the understanding of cardiac amyloidosis (CA) by investigating its unclear pathogenesis, diverse and nonspecific clinical manifestations, and the varying treatment responses and prognoses of different subtypes.
Study Methodology
Patients met strict inclusion criteria, including confirmed amyloid deposits via Congo red staining and at least one clinical indicator such as heart failure symptoms, NYHA classification, or elevated biomarkers (NT-proBNP, cTnT). Exclusion criteria eliminated cases with severe organ dysfunction, other malignancies, pregnancy, psychiatric conditions, or incomplete clinical data.
Findings
This study followed 39 patients diagnosed with cardiac amyloidosis (CA), a rare and often fatal condition caused by amyloid deposits infiltrating the heart.
The cohort consisted of 23 men (58.97%) and 16 women (41.03%), with an average diagnosis age of 60.5 years.
Many patients exhibited systemic involvement—61.54% had varying degrees of anaemia, 48.72% showed elevated cardiac troponin T (cTnT), and all patients (100%) had abnormally high N-terminal pro-brain natriuretic peptide (NT-proBNP), a key biomarker of heart failure.
Renal impairment was also common, affecting 71.79% of patients.
Electrocardiograms (ECGs) frequently showed hallmark CA patterns, including low limb-lead voltage, atrioventricular block, tachyarrhythmias, and atrial fibrillation.
Echocardiography (UCG) revealed characteristic features—atrial enlargement, weakened ventricular wall motion, and thickened interventricular septum with speckled echogenicity.
Significant mitral and tricuspid regurgitation, along with pulmonary hypertension, were also observed. Cardiac MRI confirmed ventricular thickening with delayed gadolinium enhancement, reinforcing the extensive myocardial involvement.
Congo red staining was positive in all patients, confirming amyloid deposition in affected tissues.
Despite receiving treatment, prognosis was poor. The median follow-up period was 29.5 months, during which 27 patients succumbed to progressive heart failure.
Notably, survival analysis revealed that men had significantly worse overall survival (OS) than women, and those undergoing chemotherapy or with renal impairment had particularly poor outcomes (P<0.05). These findings highlight the urgent need for earlier diagnosis, tailored treatments, and further research into the complexities of CA.
Conclusion
Cardiac amyloidosis (CA) is a rare disease resulting from systemic amyloid deposition, where accurate diagnosis and precise typing are crucial for effective management. Tailored treatment based on the specific subtype and underlying cause is essential to improving long-term outcomes.
Importance of this study for South Africa
According to researchers Madu et al.Transthyretin cardiac amyloidosis (TTR-CA) is increasingly recognized as a major cause of heart failure, potentially accounting for up to a third of diastolic heart failure cases. The pathogenic mutation of the transthyretin gene (TTR), specifically p.V142I, is prevalent in people of African descent, particularly in individuals of West African descent.1,2
These patients' significant challenges include a lack of awareness, which often leads to misdiagnosis, coupled with restricted access to diagnostic technologies and novel treatment and insufficiently trained healthcare personnel. As early diagnosis and intervention are vital for improving outcomes, underscoring the urgent need for enhanced education about CA and improved access to diagnostic care and therapeutic options for affected individuals in the region.
Access the Original Trial
Huang, H., Liu, Y., Chen, X., Guo, H., Yin, Y., Ding, M., & Liu, Y. (2024). Analysis and insights of cardiac amyloidosis: novel perception of rare diseases in cardiology. American journal of translational research, 16(9), 4534–4548. https://doi.org/10.62347/KXHZ6884
Additional References
1. Lekpa, F. K., Ndongo, S., Pouye, A., Tiendrebeogo, J. W., Ndao, A. C., Ka, M. M., & Diop, T. M. (2012). Les amyloses en Afrique subsaharienne [Amyloidosis in sub-Saharan Africa]. Medecine et sante tropicales, 22(3), 275–278. https://doi.org/10.1684/mst.2012.0085
2. Madu, E.C., Mezue, K. Uneven burden of cardiac amyloidosis in people of African descent — global imbalance in resources and access. BMC Global Public Health 1, 15 (2023). https://doi.org/10.1186/s44263-023-0
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