Association of troponin I and macrophages in cardiac tamponade with Stanford type A aortic dissection.

Background: Acute aortic dissection has a high mortality rate, especially for Stanford type A with a dissected ascending aorta. Cardiac tamponade is one of the most common complications of acute type A aortic dissection (ATAAD) and can cause death. However, the pathogenesis is often unclear. We aimed to examine laboratory findings at the onset of disease and macrophage involvement.

Methods: Hematological and biochemical parameters, and D-dimer, brain natriuretic peptide (BNP), and high-sensitivity troponin I (hs-cTnI) levels in 70 patients with ATAAD at our hospital were investigated. Additionally, the myocardium and aorta after autopsy of an ATAAD case with cardiac tamponade were pathologically examined.

Results: Forty-four ATAAD cases were complicated by cardiac tamponade. The mean age of patients with cardiac tamponade and proportion of patients over 70 years of age were both significantly higher than for those without cardiac tamponade. Evaluable D-dimer values were higher than 0.5 μg/mL in all patients. Significantly elevated laboratory parameters in patients with cardiac tamponade included: lactate dehydrogenase, aspartate aminotransferase, C-reactive protein, lactate, BNP, and hs-cTnI. However, multivariate analysis showed only hs-cTnI was significantly associated with cardiac tamponade. Histological examination revealed numerous M2-like macrophages infiltrating the myocardium and dissecting aorta, expressing CC chemokine ligand (CCL)2 together with vascular endothelial growth factor-C and matrix metalloproteinase-9. The peripheral monocyte-to-neutrophil ratio (MNR) was also significantly higher in cardiac tamponade.

Conclusions: In ATAAD patients with cardiac tamponade, hs-cTnI was significantly elevated and CCL2 expression was observed, which may be involved in the expression of M2-like macrophages via an increased MNR.