An atherosclerotic plaque requires a nutrient blood supply, which is predominantly derived from arterial vasa vasorum. A variety of factors (environmental and genetic) contribute to the initiation and growth of atherosclerosis within vessel walls. Chemotactic factors, such as tissue ischemic and hypoxic factors, stimulate the release of vascular endothelial growth factor (VEGF) proteins, resulting in vessel wall angiogenesis. These developments often precede the formation of the luminal plaque. In this report, we describe the use of contrast-enhanced carotid ultrasound (CECU) imaging for the detection and quantification of intra-plaque neovascularization. The efficacy of CECU was measured against the neovascular density observed within the tissue specimens obtained at the time of carotid endarterectomy surgery. The objective of this study was to provide a histologic correlation between CECU and carotid artery atherosclerotic plaque neovascularization. Fifteen patients with significant atherosclerotic carotid artery disease received a CECU examination prior to undergoing a carotid endarterectomy (CEA). Two patients received bilateral endarterectomies, resulting in a total of 17 cases. At the time of surgery, carotid plaque samples were surgically removed and stained with specific vascular markers (CD31, CD34, von Willebrand factor, and hemosiderin) designed to identify the presence and degree of neovascularization. The intra-plaque neovascularization recorded on preoperative CECU was correlated with the degree of neovascularization noted in the tissue specimens. The CECU neovascularization was correlated to CD31-stained tissue specimens. This correlation value was 0.68 using Spearman's rank method. When CECU results were correlated with the other histologic markers (CD34, von Willebrand factor, and hemosiderin), a correlation of 0.50 was obtained. In conclusion, contrast-enhanced carotid ultrasound correlated to the presence and degree of intra-plaque neovascularization as determined from histology specimens.
Safety of carotid artery surgery depends on proper case selection, meticulous surgical technique, and appropriate protection of the brain during carotid artery cross‐clamping. Various methods have been devised to determine the adequacy of collateral circulation, none of which has been proven practical and totally reliable. Attempts at increasing cerebral perfusion to the ischemic portion of the brain by induced hypertension, hypercarbia, and hypocarbia have been ineffective.
The purpose of this presentation is to report our experience with routine intraluminal shunting in carotid artery surgery during the past 17 years. Advantages of routine shunting include maintenance of regional cerebral blood flow at the preclamping level and the elimination of any need for monitoring and haste during surgery. Insertion of the tube, properly done, does not injure the arterial wall and should not cause embolization. The presence of the tube within the arterial lumen does not interfere with exposure of the atheroma, yet it facilitates repair of the incision and prevents stricture by faulty suturing technique. Results of carotid artery surgery measured by the incidence of stroke are compared between shunted and nonshunted series. A review of the literature confirms our impression that shunting reverses ischemic changes detected by EEG and regional cerebral blood flow determinations. The usefulness of shunting in the surgical management of internal carotid aneurysm, kinked carotid artery, carotid body tumor, and carotid‐subclavian bypass graft is also described.
Noninvasive surrogate markers of atherosclerosis allow the physician to identify subclinical disease before the occurrence of adverse cardiovascular events, thereby limiting the need to perform invasive diagnostic procedures. Imaging modalities, such as carotid artery ultrasound, two-dimensional echocardiography, coronary artery calcium imaging, cardiac magnetic resonance imaging, ankle-brachial indices, brachial artery reactivity testing, and epicardial coronary flow reserve measurements, provide information that may improve the predictive value of a person's risk of developing clinically significant atherosclerotic disease. Newer imaging modalities have also emerged to bring insight into the pathophysiology and treatment of atherosclerosis.
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