SCAN-MP Study: High Prevalence of Transthyretin Cardiac Amyloidosis in Older Black and Hispanic Individuals with Heart Failure

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By Lucas Marinacci on

Key Points

  • ATTR cardiac amyloidosis (ATTR-CA) is frequently diagnosed in older Black individuals with heart failure (HF), particularly in men over 75 years of age.
  • The SCAN-MP study provides observational data showing an overall prevalence of 6.5% for transthyretin cardiac amyloidosis (ATTR-CA) among Black and Caribbean Hispanic individuals aged 60 and older with HF.
  • Most cases of ATTR-CA (60.5%) were wild-type (ATTRwt-CA), while 39.5% were hereditary (ATTRv-CA) associated with the V142I TTR gene variant.
  • Prevalence in Black participants was markedly higher than in Hispanic participants, emphasizing the importance of targeted screening in high-risk populations.
  • A genotype-first approach would miss over half of affected individuals, as many cases are wild-type ATTR-CA, highlighting the importance of imaging in the diagnostic algorithm.

ATTR-CA is a treatable but underdiagnosed cause of heart failure (HF) in older adults, especially in minoritized populations. ATTR-CA is caused by deposition of transthyretin amyloid fibrils in cardiac tissue, either due to sporadic disease (wild-type or ATTRwt-CA) or because of an underlying genetic mutation (variant ATTR or ATTRv-CA). The most common TTR mutation, V142I (formerly V122I), occurs in 3.4% of self-identified Black US adults and has been linked to increased morbidity and mortality.

On November 18th  2024, the results of “The Screening for Cardiac Amyloidosis with Nuclear Imaging in Minority Populations (SCAN-MP) Study” were presented at AHA Scientific Sessions 2024. The purpose of this study was to determine the prevalence of ATTR-CA among a sample of older Black or Hispanic patients with HF as well as the proportions of those with ATTRv-CA versus ATTRwt-CA.

This prospective, multi-center, observational cohort study included 650 Black or Caribbean Hispanic individuals aged 60 years or older with heart failure. Participants with normal left ventricular (LV) wall thickness or an LV ejection fraction (LVEF) of less than 30% were excluded. ATTR-CA was diagnosed using Tc-99m-pyrophosphate scintigraphy, alongside blood testing to exclude light-chain amyloidosis, and genetic testing to identify TTR gene variants. Comprehensive echocardiographic, biochemical, physical performance, and symptom burden data were collected (NCT03812172). The mean age was 73 years, 50.6% were women, and 71.4% identified as Black, with a median wall thickness of 13mm and median LVEF 61%.

The study found an overall prevalence of ATTR-CA of 6.5% (95% CI 4.6-8.5). Of these cases, 60.5% were wild-type ATTR-CA, while 39.5% were hereditary ATTRv-CA linked to the V142I mutation.  The overall prevalence of V142I allele was 5.6% and among participants carrying the V142I allele, 45.5% had ATTRv-CA. The prevalence of ATTR-CA was significantly higher in Black participants (8.3%) compared to Hispanic participants (2.2%; p<0.01). In Black participants, prevalence increased markedly with age, rising from 3.9% in those aged 75 years or younger to 15.8% in those over 75 years (p<0.0001). The highest prevalence (20%) was observed in Black men older than 75 years.

The findings from SCAN-MP highlight that relying solely on genetic testing would miss more than half of cases, as wild-type ATTR-CA accounted for the majority of diagnoses. It also underscores the importance of imaging-based screening in high-risk populations, particularly older Black individuals with increased LV wall thickness or unexplained heart failure symptoms. There is a critical need for targeted diagnostic strategies and comprehensive screening programs to improve detection, enable timely treatment, and ultimately improve outcomes for at-risk groups.

 

  1. Ruberg FL, Blaner WS, Chiuzan C, Connors LH, Einstein AJ, Fine D, Helmke S, Kurian D, Pandey S, Raiszadeh F, Rodriguez C, Sabogal N, Teruya S, Winburn M, Chung WK, Cohn E, Miller EJ, Kelly JW, Maurer MS. Design and Rationale the SCAN-MP (Screening for Cardiac Amyloidosis With Nuclear Imaging in Minority Populations) Study. J Am Heart Assoc. 2023 Apr 18;12(8):e028534. doi: 10.1161/JAHA.122.028534. Epub 2023 Apr 17. PMID: 37066788; PMCID: PMC10227254.