Plaque Composition and No-Reflow Phenomenon During Percutaneous Coronary Intervention of Low-Echoic Structures in Grayscale Intravascular Ultrasound

Abstract

It has been reported that coronary vasa vasorum is associated with plaque vulnerability, and low-echoic structures in grayscale intravascular ultrasound (IVUS) are consistent pathologically with vasa vasorum. However, the association of low-echoic structures with plaque composition and no-reflow phenomenon during percutaneous coronary intervention (PCI) is unclear. We investigated plaque composition in virtual histology IVUS (VH-IVUS) and no-reflow phenomenon during PCI of low-echoic structures.A total of 106 lesions being treated by VH-IVUS before PCI were included in this study. Low-echoic structure was defined as a small tubular structure exterior to media without a connection to the vessel lumen in ≥ 3 consecutive crosssectional IVUS images. Lesions with low-echoic structures were found in 42% (45/106).Lesions with low-echoic structures were more prevalent in acute coronary syndrome (ACS) patients (53% [24/45] versus 20% [12/61], P < 0.001), had more positive remodeling (49% [22/45] versus 21% [13/61], P = 0.003), a larger number of VH-IVUS derived thin-cap fibroatheromas (VH-TCFAs) (0.64 ± 0.53 versus 0.05 ± 0.22, P < 0.001), more VH-TCFAs with a baseline plaque burden of 70% or more and minimal luminal area of 4.0 mm(2) or less (29% [13/45] versus 2% [1/61], P < 0.001), and more frequent no-reflow phenomenon after stent implantation and more final TIMI flow grade 0/1/2 (38% [17/45] versus 5% [3/61], P < 0.001; 9% [4/45] versus 0% [0/61], P = 0.03) than lesions without low-echo structures.Lesions with low-echoic structures in grayscale IVUS had high plaque vulnerability and were more prevalent in ACS patients, positive remolding, and VH-TCFAs, and they had more frequent no-reflow phenomenon during PCI than lesions without low-echoic structures.

Determinants of Slow Flow in Percutaneous Coronary Intervention to the Culprit Lesion of Non-ST Elevation Myocardial Infarction

“…Furthermore, this study was underpowered to prove the safety of modest stent expansion. In addition, although the low attenuation plaque was considered as a risk factor for slow flow phenomenon and distal embolization, 30) our study could not show the significant association between the low attenuation plaque and slow flow, while the presence of low attenuation plaque was numerically greater in the slow flow group (52.9%) than in the non-slow flow group (36.1%) without reaching statistical significance (P = 0.18). This study was also underpowered to prove the association between the low attenuation plaque and slow flow.…”

“…The main point of the modest stent expansion strategy was to avoid stent overexpansion. Because the culprit of acute coronary syndrome shows greater positive remodeling than that of stable disease, 30) operators tend to select big stent if only the positively remodeled culprit was used for vessel reference. In the modest stent expansion strategy, we might select appropriate size of stent by checking the lumen size at the distal reference segments 31) rather than the lumen size at the culprit.…”

Risk Factors for No-Reflow Phenomenon after Percutaneous Coronary Intervention in Patients with Acute Coronary Syndrome

“…No-reflow phenomenon is one of the common complications after emergency PCI, with incidence rates of 5-25% 8 . Its pathophysiological mechanisms mainly include endothelial dysfunction, microvascular dysfunction, microvascular spasm, reperfusion injury, and microvascular embolism, among others.…”

Association of Isoprostanes-Related Oxidative Stress with Vulnerability of Culprit Lesions in Diabetic Patients with Acute Coronary Syndrome

“…A cute coronary syndrome (ACS) is a group of severe cardiovascular diseases and the common cause of cardiac death worldwide. Some pathological evidences showed that ACS is likely caused by vulnerable coronary plaques, 1) which is characterized by thin-cap fibroatheroma (TCFA), large lipid-rich necrotic core, and macrophage infiltration. 2,3) Severe atherosclerotic lesions are frequently observed in diabetic patients.…”