Lesions Of Brachiocephalic Arteries Research Articles

Computational Stress Analysis of Atherosclerotic Plaques in ApoE Knockout Mice

The aortic sinus lesions of apolipoprotein E knockout (ApoE KO) mice seldom show any signs of fibrous cap disruption, whereas cap ruptures have been recently reported in the proximal part of their brachiocephalic arteries (BCA). We use histology based finite element analysis to evaluate peak circumferential stresses in aortic and BCA lesions from six 42-56 week-old fat-fed ApoE KO mice. This analysis is able to both explain the greater stability of aortic lesions in mice and provide new insight into the BCA lesion as a model for the stability of human lesions with and without microcalcifications in their fibrous caps. The predicted average peak stress in fibrous caps of aortic lesions of 205.8 kPa is significantly lower than the average value of maximum stresses of 568.8 kPa in BCA caps. The aortic plaque stresses only slightly depend on the cap thickness, while BCA lesions demonstrate an exponential growth of peak cap stresses with decreasing cap thickness similar to human vulnerable plaques. Murine BCA ruptured lesions with mean cap thickness of 2 microm show stresses approximately 1400 kPa, three times higher than human ruptured plaques with a mean cap thickness of 23 microm without microcalcifications in the cap, but nearly identical to the peak stress around an elongated microcalcification with aspect ratio 2 in a human thin cap approximately 50 microm thick. We predict biomechanical stress patterns in mouse BCA close to human vulnerable plaques without microcalcification in the cap, while aortic lesions show stress tendency similar to stable lesions in human.

Transgenic human CRP is not pro-atherogenic, pro-atherothrombotic or pro-inflammatory in apoE−/− mice

The pathogenic significance, if any, of the epidemiological association between baseline C-reactive protein (CRP) values and future atherothrombotic events is not known. We therefore investigated spontaneous atherosclerosis and atherothrombosis, and systemic markers of inflammation (acute phase proteins), in aged, normal diet-fed, male apolipoprotein E deficient (apoE−/−) mice with and without transgenic expression of human CRP. At 18 months of age, aortic atherosclerosis was extensive but with no significant difference in plaque size between C57BL/6apoE−/− mice with (apoE−/−-hCRP+) and without transgenic human CRP (apoE−/−). Atherosclerotic lesions in brachiocephalic arteries were typically complex and layered, with extensive fibrotic-cholesterol deposits, calcification and occasional recent intraplaque haemorrhage and thrombus, but with no significant overall differences between apoE−/− and apoE−/−-hCRP+ animals. Concentrations of mouse serum amyloid P component (SAP) were essentially normal throughout and did not differ between apoE−/− and apoE−/−-hCRP+ mice, or between wild-type (apoE+/+) and apoE−/− mice, regardless of human CRP expression. Mouse serum amyloid A protein (SAA), and human CRP concentrations were modestly but significantly higher in apoE−/−-hCRP+ than in apoE+/+-hCRP+ animals, but mouse SAA values were unaffected by transgenic expression of human CRP in either background. Thus, there was no evidence in this 18 month study of apoE−/−, and control apoE+/+ mice, that transgenic human CRP was pro-atherogenic, pro-inflammatory or pro-atherothrombotic.

Endovascular procedures in the treatment of obstructive lesions of the brachiocephalic arteries

To assess the early effects, possible risks, and long term results of percutaneous transluminal angioplasty (PTA) of brachiocephalic trunk (BT) and subclavian arteries (SA). During the period of 11 years, in 92 patients (57 males--62%, mean age 53.5 +/- 7.8 years) 93 PTA of SA/BT were performed; 70 (75%) lesions were stenosis, while 23 (25%) lesions were occlusions with mean diameter stenosis percent of 83.1 +/- 6.2%. Clinical indications were: vertebrobasilar insufficiency (n = 57), upper limb ischemia (n = 40), coronary steal syndrome (n = 4) and scheduled aorto-coronary bypass, using internal thoracic artery (ITA) (n = 4 asymptomatic patients). Mean lesion length was 22 +/- 8 mm. Eighty one (87%) out of 93 lesions were successfully dilated; all of 12 (13%) failures were due to unsuccessful recanalisation of occluded arteries. In 10 patients 10 stents were implanted (2 in BT and 8 in left SA). There were 6 (6.5%) procedural complications: 1 dissection, 1 thrombosis of the left SA, transient ischemic attack in 2 patients, and 2 cases of dislocation of atheromatous plaque from the right SA into the right common carotid artery. During the follow-up of 48 +/- 3 months, 16(20%) restenoses were treated by PTA (n = 7) or operatively (n = 9). Primary and secondary patency for all lesions treated during 11 years was 87% and 80%, respectively (stenosis: 97% and 89%; occlusions: 58% and 58%). PTA with or without stenting was relatively simple, efficient and safe procedure. It required short hospitalization with low treatment costs. If any of suboptimal results or chronic occlusions were present, the implantation of endovascular stents should have been considered.

The Isolated Posttraumatic Aneurysm of the Brachiocephalic Artery After Blunt Thoracic Contusion

Most supra-aortic aneurysms are localized in the extracranial carotid and subclavian artery. Aneurysms of the brachiocephalic artery (BCA) represent a rather rare finding. Chronic arteriosclerotic changes are responsible for the majority of cases. Posttraumatic BCA damage is only occasionally encountered, complete vascular dissection by perforating injuries being the dominant causative mechanism. Although isolated BCA trauma after blunt thoracic contusion is rare, brachiocephalic injury in association with aortic lesions seems to be the second most common site of vascular injury after the aorta. Cases of isolated blunt BCA trauma documented in the literature to date usually involved a complete avulsion of the artery from the aortic arch or complete rupture near the aortic origin. We present an isolated case of posttraumatic BCA aneurysm in a woman involved in a car accident who suffered blunt chest trauma with a subtotal, near circumferential vessel wall dissection of only the intima and media. Clinical features, diagnostic procedure, surgical treatment, and trauma mechanisms of postcontusional BCA lesions are described and discussed in reference to the literature.

Model of cerebral ischemia in dogs with pathological kinking and occlusion of the carotid arteries

An experimental model of brain ischemia in pathological kinking and occlusion of carotid artery has been developed on 40 dogs. Each model was documented angiographically, controlled with radionuclides, evaluated morphofunctionally. Basing on the results, surgical indications for correction of brachiocephalic artery lesions are provided.

Morphologic characteristics of naturally occurring atherosclerosis in the brachiocephalic artery of the pigeon

Endothelial characteristics and the macrophage foam cell nature of early naturally occurring lesions in the aorta and coronaries of the pigeon have been well characterized. However, the characteristics of pigeon atherosclerosis at other vascular sites have not been extensively studied. The present study was designed to compare atherosclerosis in the brachiocephalic artery with that in the coronaries and aorta. Forty-six White Carneau (WC) pigeons (26 female, 20 male) ranging in age from 2.5 to 7 years were necropsied after fixation under deep anesthesia by perfusion at 160 mm Hg with buffered glutaraldehyde. Arteries stained with Sudan IV for gross evaluation were subsequently processed for SEM and TEM. The occurrence of sudanophilia in the proximal brachiocephalic artery was greater in females ( 22 26 ) than in males ( 2 20 ). The endothelium, as studied by SEM, was intact over all normal and sudanophilic areas. Cell morphology varied with location in the vessel and gradually changed from polygonally shaped cells with prominent margins and protruding nuclei in the proximal brachiocephalic artery to elongated, flattened cells in distal regions. These regional differences were consistently observed, and did not correlate with age, gender, or areas of lipid accumulation. Unlike lesions in the coronary arteries and at the celiac bifurcation of the aorta, a relative paucity of white blood cells over diffuse sudanophilic areas was observed. This lack of adherent monocytes correlated with lesion ultrastructure. Connective tissue in the intima of the sudanophilic brachiocephalic arteries was disorganized, reflecting both an increase in matrix components and the presence of massive pools of extracellular lipid. Intracellular lipid was minimal and when present was confined to random droplets in the cytoplasm of intimal smooth muscle cells. Monocyte-derived foam cells, characteristic to other vascular beds, were absent from the brachiocephalic artery lesions. These results document differential lesion composition in the WC pigeons and suggest a gender-related susceptibility for brachiocephalic artery atherosclerosis in pigeons.