ABSTRACT
OBJECTIVES: One possible reason for the long-term patency of no-touch saphenous vein grafts is the preservation of the vasa vasorum in the adventitia/perivascular adipose tissue. In this study, we investigated the vasa vasorum of the no-touch saphenous vein graft in vivo using frequency-domain optical coherence tomography, performed qualitative and quantitative analyses, and compared them with the conventional saphenous vein graft. METHODS: A frequency-domain optical coherence tomography study was performed on 14 saphenous vein grafts at the postoperative coronary angiography 1-2 weeks after surgery (no-touch group, n = 9; conventional group, n = 5). RESULTS: Many signal-poor tubular lumen structures that can be recognised in the cross-sectional and longitudinal profiles, which indicates the vasa vasorum, were observed in the adventitial/perivascular adipose tissue layer in the no-touch saphenous vein grafts. In contrast, the vasa vasorum was less abundant in the conventional saphenous vein grafts. The vasa vasorum volume per millimetre of graft in the no- touch group was significantly higher than in the conventional group (0.0020 [0.0017, 0.0043] mm3 and 0.0003 [0.0000, 0.0006] mm3, P = 0.023). CONCLUSIONS: Frequency-domain optical coherence tomography showed abundant vasa vasorum in the thick adventitia/perivascular adipose tissue layer of no-touch saphenous veins in vivo. In contrast, few vasa vasorum was observed in the conventional saphenous vein grafts.
ABSTRACT
Thrombus formation plays a crucial role in the clinical treatment of certain diseases. In conditions such as aortic dissection and cerebral aneurysm, complete thrombus occlusion in the affected region is desired to reduce blood flow into the false lumen or aneurysm sac, leading to a decrease in the tension exerted on the vascular wall and making it less likely to rupture. However, desired thrombosis sometimes fails to occur. Predicting thrombus formation can provide valuable information in such cases. This article offers a comprehensive review of conventional methods for predicting thrombus formation. In reviews conducted from the year 2000 to the present, the number of published related papers every five years has increased more than tenfold. We also found that the predictive methods can be classified into two categories: those based on the hemodynamic evaluation parameters and those based on hemodynamic and mathematical models that simulate the transport and reaction of blood components. Through our discussions, we identified several challenges that need to be resolved, including predictions based on patient-specific condition, model validation, multi-scale problems, the mechanisms of thrombus formation, and ensuring cost effectiveness. This review aims to guide researchers interested in exploring thrombus formation prediction within clinical treatments.
ABSTRACT
Computational fluid dynamics was performed to simulate haemodynamics of type B aortic dissection complicated by mesenteric malperfusion caused by dynamic obstruction in a 70-year-old man. Streamline analysis showed disappearance of antegrade flow in the false lumen of the descending aorta and attenuation of intermittent flap-induced disruption of visceral vessel perfusion after entry coverage. Quantitative analysis showed endovascular repair increased perfusion volume of the coeliac artery and superior mesenteric artery by 55.6% and 77.4%, respectively. Entry closure with thoracic endovascular prosthesis improved mesenteric malperfusion by attenuating the intermittent flap-induced perfusion disruption.