Spontaneous ruptured aortic plaque and injuries: insights for aging and acute aortic syndrome from non-obstructive general angioscopy

Abstract

Recent advances in non-obstructive general angioscopy (NOGA) have enabled the detection of aortic atherosclerosis. The incidence of spontaneous ruptured aortic plaques (SRAPs) and aortic injuries was found to be high in patients diagnosed with or suspected of having coronary artery disease. These facts may result in a paradigm shift for diseases such as aging and acute aortic syndrome because the incidence of systemic embolic diseases and aortic disease are assumed be high. Aortic thromboembolism has been thought to be mainly iatrogenic and is referred to as "cholesterol embolization syndrome" or "cholesterol crystal embolization", although the cholesterol crystals (CCs) were not demonstrated routinely as real images. Atheromatous materials, fibrins, calcifications, macrophages, and a mixture of such substances are released through a puff or puff-chandelier rupture. Among atheromatous materials, CCs can be easily detected clinically in sampled blood via polarized light microscopy. Atheromatous materials include rich CCs and free monolayers, and multilayer CCs are released when the atheromatous materials from vulnerable plaques break into pieces, such as in puff or puff-chandelier rupture. Released SRAPs seem to be asymptomatic; however, accumulation of SRAPs referred to as accumulated spontaneous asymptomatic plaques may cause aging through systemic "embolic" processes, such as mechanical obstruction and an inflammasome pathway. Unique findings in "atherosclerotic" acute aortic syndrome, such as a clear boundary between the dissected lesion and the normal lesion, fissure/fissure bleeding suggesting an entry or a reentry, and subintimal blood flow detected through NOGA are reported. Fissure/ fissure bleeding and subintimal blood flow may be the first or last triggers of "atherosclerotic" acute aortic syndrome. Pre-emptive diagnosis and risk stratification of acute "atherosclerotic" aortic dissection and feedback for endovascular therapy may be enabled through the use of NOGA in the future.

Acute thoracic aorta dissection: unraveling the pathophysiology of a silent killer

“…The endothelium is activated by the expression of adhesion molecules, in addition to high levels of interferon alpha and beta that are generated after activation of the Toll-like receptor 9. T cells produce pro-inflammatory mediators, such as interferon gamma (IFN-γ), which favors the adhesion of monocytes to the endothelium and their migration to the intimal layer, leading to a local inflammatory action [12][13][14][15] .…”

“…T lymphocytes and macrophages can be found diffusely along the medial layer, in focal accumulations between the layers of SMCs, and within the wall of the vasa vasorum, suggesting its possible migration from the adventitia to the media of the aortic wall. These inflammatory cells are potential sources of proteases that can degrade the ECM and lead to aortic wall weakening, called tunica media degeneration [13][14][15][16][17][18] .…”

“…In contrast, the increased expression and disordered collagen deposition may correspond to a slow repairing and pro-fibrotic process triggered by the fragmentation and depletion of elastic fibers. This fibrosis can also be due to an increase in the expression and release of growth factors that can culminate in an increase in collagen and consequent increase in arterial stiffness (Figure 3) [13][14][15][16][17][18][19][20][21][22][23][24][25] .…”

Preventive Effects of Quercetin against the Onset of Atherosclerosis-Related Acute Aortic Syndromes in Mice

“…Aortic aneurysms and aortic dissection are among the atherosclerosis-related acute aortic syndromes [ 1 , 2 , 3 ]. An aneurysm is a condition in which a part of the wall of the aorta circumferentially or locally enlarges or protrudes [ 4 ].…”

A new beginning of aortic angioscopy in diagnosis and treatment in acute aortic syndrome?

“…This is due to the advantage of angioscopic high spatial resolution of 150 mm, which is superior to other devices including CT, MRI and TEE. Also, the aortic angioscopy has excellent features to visualize dynamic changes of aortic plaques, disruption spontaneously plaque rupture among other things [6]. Accurate observing the inside of aortic lumen with non-obstructive angioscopy will come to be able to evaluate the development of aortic atherosclerosis.…”