Vascular grafts

Autogenous vein is the conduit of choice in the surgical creation of bypasses of small–to– medium–caliber vessels in patients with peripheral occlusive arterial disease and will remain so for the near future. The success rate of bypasses using conduits of diameters greater than 6 mm has been excellent, whereas the majority of bypasses using smaller conduits fail within 5 years. In addition, due to a steep increase in rates of diabetes and decreasing cardiovascular mortality rates, increasing challenges are presented by this population. These facts have motivated much of the research in the cardiovascular arena over the past four decades, with improved techniques and new materials. Strategies to improve outcomes include the use of alternative materials including autologous, nonautologous and prosthetic grafts, utilizing different methods for their harvesting and preservation; tissue engineering, using either polymer– or biological–based scaffolds for cell seeding; endovascular methodologies; and gene therapy. This report presents an overview of the several options currently available in the management of patients with peripheral arterial occlusive disease, as well as the ongoing research directed towards the creation of an artificial engineered vessel, discussing experimental work in which endothelial cells have been seeded on different scaffolds and finally the potential application of gene therapy in the field of vascular reconstruction.     

Vascular graft research: endothelial cell seeding of synthetic bypass grafts

Over thirty years ago, bypass grafts first became available for human use. This technological development provided patients with improved functioning and quality of life. It is a peculiarity of nature that humans do not heal synthetic bypass grafts with an endothelial lining as other animals will. Researchers have developed the technology to take endothelial cells from a peripheral vein of a person and plant them inside a synthetic bypass graft. Now, science has progress to the point of applied research. In the application of this research to patients, knowledge will be obtained to see if seeding of grafts makes a difference. Hope is on the forefront that peripheral vascular surgery patients may be able to have synthetic grafts that are more like the vessels that they were created with and this will lead to improved functioning and quality living.     

Vascular embolization

Summary

Vascular embolization has been shown to be of great value in a variety of clinical situations, and in many of these itshould be the procedure of first choice, either prior to, or as an alternative to, more conventional surgical or medical therapy. Clinicians should be aware of the numerous indications for this technique and the often excellent results that are obtained. This article describes the techniques used for vascular occlusion, defines many of its indications and reviews some of the results and complications that have been reported with embolization procedures.     

Vascular regeneration

Tissue regeneration by using stem/progenitor cells has been recognized as a maintenance or recovery system of many organs in adult. The isolation of endothelial progenitor cells (EPCs) derived from the peripheral blood (PB) was one of the amazing discovery for the recognition of "neovessel formation" in adult occurring as physiological and pathological responses. These findings that EPCs home to sites of neovascularization and differentiate into endothelial cells (ECs) in situ is consistent with "vasculogenesis", a critical paradigm well described for embryonic neovascularization, but proposed recently in adults in whom a reservoir of stem or progenitor cells contributes to vascular organogenesis. On the basis of the regenerative potency, these stem/progenitor cells are expected as a key factor of therapeutic applications for the ischemic diseases.     

血管性帕金森综合征

随影像学发展和尸解病例增多 ,血管性帕金森综合征已渐为人们所认识。本文对血管性帕金森综合征的病因、发病机制、病理改变、临床表现、血液流变学、经颅多普勒、头颅CT、MRI改变 ,诊断与鉴别诊断以及治疗和康复等研究进展进行综述     

Vascular syndromes

Patients with suspected transient ischemic attacks are frequently seen in the Emergency Department. Accurate diagnosis is crucial but often very difficult because signs and symptoms often will have resolved when the patient is seen. This article reviews the details of the history and physical examination that may help to establish a correct diagnosis.     

Vascular depression

It has been reported that 20-65% of cerebral infarction patients suffers from depression. On the other hand, elderly-onset depression has more cerebro-vascular changes such as deep white matter lesion and periventricular hyperintensity on MRI than young-onset depression. These findings together leads new disease category 'vascular depression' (VD), meaning depression primarily caused by cerebral infarction. VD patients show less family history and symptomatic changes within a day than those with non-vascular depression. Though anti-depressants are effective on VD, they have higher incidence of side effect on VD than on non-vascular depression. Benzodiazepines and cerebral circulation and metabolism enhancers are also used in VD therapy. The prognosis of VD is worse than that of non-VD or cerebral infarction without depression.     

Recanalization of autogenous vein grafts

I have documented the recanalization of a venous graft placed in the peripheral venous system to replace a severely disrupted peripheral vein. This case demonstrates the feasibility of such a maneuver, where indicated, to preclude large vein ligation or permanent venous obstruction resulting from inappropriate venography.