AimsCardiac 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.Methods and resultsThe 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/m2 [41.1–59.8] vs. 55.7 g/m2 [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).ConclusionsMicrovascular 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.

中文翻译：

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心脏淀粉样变性中的微血管阻塞


目的心脏淀粉样变性 （CA） 的特征是淀粉样原纤维在细胞外间隙内沉积，导致心肌结构和毛细血管结构混乱。本研究旨在描述 CA 患者微血管阻塞 （MVO） 的患病率，并评估 MVO 与预后之间的关联。方法和结果研究人群包括 800 名患者，其中 400 名患有轻链 CA （AL-CA），400 名患有转甲状腺素蛋白 CA （ATTR-CA）。221 例 （27.6%） 患者存在 MVO，在 ATTR-CA 中比在 AL-CA 中更常见 （124 例 [56.1%] 对 97 例 [43.9%]，p = 0.033）。MVO 患者的心脏表型更严重，表现为较高的 N 末端脑钠肽前体（3516 ng/L [1944–6247] vs. 2508 ng/L [1203–5752]，p < 0.001），较差的整体纵向应变（-10.5% [-12.6;-7.9] vs. -12.0% [-16.0;-8.9]，p < 0.001）和较高的细胞外体积（56% [51–61] vs. 50% [45–57]， p < 0.001）。AL-CA和MVO患者的血清肌钙蛋白较高（86 ng/L [47–148] vs. 59 ng/L [44–78]，p < 0.001）和较高的T2（53 ms [50–56] vs. 50 ms [48–52]，p < 0.001），但细胞外体积较低（55% [50–60] vs. 58% [53–61]，p = 0.008）和较低的索引肌细胞体积（48.6 g/m2 [41.1–59.8] vs. 55.7 g/m2 [47.5–68.4]， p < 0.001） 比 ATTR-CA 和 MVO 患者。MVO 与总体人群 （风险比 [HR] 1.28,95% 置信区间 [CI] 1.03-1.59，p = 0.025）和 AL-CA 亚组 （HR 1.59,95% CI 1.17-2.17，p = 0.003） 但不 ATTR-CA （HR 1.04,95% CI 0.77-1.40，p = 0.814） 的死亡风险增加相关。结论微血管梗阻在 CA 中很常见，与淀粉样蛋白浸润标志物有关。 MVO 与 AL-CA 的死亡风险增加相关，但在 ATTR-CA 中则无关。这反映了这两种形式的 CA 之间疾病生物学的内在差异，MVO 可能与多个心肌过程、淀粉样蛋白浸润、水肿和心肌细胞死亡有关。