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Microvascular obstruction in cardiac amyloidosis.

Authors :: Netti L
Ioannou A
Martinez-Naharro A
Razvi Y
Porcari A
Venneri L
Maestrini V
Knight D
Virsinskaite R
Rauf MU
Kotecha T
Patel RK
Wechelakar A
Lachmann H
Kellman P
Manisty C
Moon J
Hawkins PN
Gillmore JD
Fontana M
Source :: European journal of heart failure [Eur J Heart Fail] 2024 Oct 18. Date of Electronic Publication: 2024 Oct 18.
Publication Year :: 2024
Publisher :: Ahead of Print
Abstract: Aims: Cardiac amyloidosis (CA) is characterized by deposition of amyloid fibrils within the extracellular space, causing disarray of the myocardial structure and capillary architecture. This study aims to characterize the prevalence of microvascular obstruction (MVO) in patients with CA and to assess the association between MVO and prognosis.<br />Methods and Results: The study population comprised 800 patients, of which 400 had light-chain CA (AL-CA) and 400 had transthyretin CA (ATTR-CA). MVO was present in 221 (27.6%) patients, and more common in ATTR-CA than AL-CA (124 [56.1%] vs. 97 [43.9%], p = 0.033). Patients with MVO had a more severe cardiac phenotype evidenced by higher N-terminal pro-brain natriuretic peptide (3516 ng/L [1944-6247] vs. 2508 ng/L [1203-5752], p < 0.001), worse global longitudinal strain (-10.5% [-12.6; -7.9] vs. -12.0% [-16.0; -8.9], p < 0.001), and higher extracellular volume (56% [51-61] vs. 50% [45-57], p < 0.001). Patients with AL-CA and MVO had a higher serum troponin (86 ng/L [47-148] vs. 59 ng/L [44-78], p < 0.001), and higher T2 (53 ms [50-56] vs. 50 ms [48-52], p < 0.001), but lower extracellular volume (55% [50-60] vs. 58% [53-61], p = 0.008) and lower indexed myocyte cell volume (48.6 g/m <superscript>2</superscript> [41.1-59.8] vs. 55.7 g/m <superscript>2</superscript> [47.5-68.4], p < 0.001) than patients with ATTR-CA and MVO. MVO was associated with an increased risk of mortality in the overall population (hazard ratio [HR] 1.28, 95% confidence interval [CI] 1.03-1.59, p = 0.025), and the subgroup with AL-CA (HR 1.59, 95% CI 1.17-2.17, p = 0.003) but not ATTR-CA (HR 1.04, 95% CI 0.77-1.40, p = 0.814).<br />Conclusions: Microvascular obstruction is common in CA and is related to markers of amyloid infiltration. MVO is associated with an increased risk of mortality in AL-CA, but not in ATTR-CA. This reflects the intrinsic differences in disease biology between these two forms of CA, with MVO likely related to multiple myocardial processes, amyloid infiltration, oedema and myocyte death.<br /> (© 2024 The Author(s). European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)