Isolated Dissection of the Ductus Arteriosus Associated with Sudden Unexpected Intrauterine Death

We report five cases of sudden intrauterine death due to premature closure of the ductus arteriosus. In four cases, this was caused by dissecting the hematoma of the ductus arteriosus with intimal flap and obliteration of the lumen. In one case, the ductus arteriosus was aneurysmatic, with lumen occlusion caused by thrombus stratification. No drug therapy or free medication consumption were reported during pregnancy. The time of stillbirth ranged between 26 and 33 gestational weeks. We performed TUNEL analysis for apoptosis quantification. The dissecting features were intimal tears with flap formation in four of the cases, just above the origin of the ductus arteriosus from the pulmonary artery. The dissecting hematoma of the ductus arteriosus extended downward to the descending aorta and backward to the aortic arch with involvement of the left carotid and left subclavian arteries. TUNEL analysis showed a high number of apoptotic smooth muscle cells in the media in two cases. Abnormal ductal remodeling with absence of subintimal cushions, lacunar spaces rich in glycosaminoglycans (cystic medial necrosis), and smooth muscle cell apoptosis were the pathological substrates accounting for failure of remodeling process and dissection.

Age-Related Changes in the Canine Aorta

Degenerative changes in the aorta are commonly observed in both dogs and humans, and those changes that occur with age morphologically overlap with those observed in genetic or degenerative diseases. Therefore, recognition of age-related aortic changes is important for diagnosticians, as such histologic findings should be distinguished from lesions of specific diseases. The aortas from 37 dogs without clinical cardiovascular disease ranging in age from 2 months to 15 years were divided into 3 cohorts to assess age-relatedness, and evaluated histologically using standardized nomenclature and diagnostic criteria adapted and modified from the human literature. We found that the histopathologic severity scores for intimal thickening, translamellar medial fibrosis, loss of smooth muscle cell nuclei, and medial microcalcification were higher in older dogs, whereas the scores for both intralamellar and translamellar mucoid extracellular matrix accumulation (“cystic medial necrosis”) were not different among age groups. Dogs with translamellar medial fibrosis and aortic medial microcalcification were significantly older compared with dogs without these findings, while the presence of aortic medial chondro-osseous metaplasia was not related to age. Taken together, we demonstrate a range of age-related aortic histologic changes in dogs without clinical cardiovascular disease and suggest that integration of signalment and clinical data can aid in the differentiation of such findings from non-age-related disease processes.

Endovascular Embolization of a Dissected External Carotid Artery Pseudoaneurysm in a Young Female with Neurofibromatosis Complicated by Preeclampsia

Carotid artery pseudoaneurysms are infrequently encountered in clinical practice. Major contributory etiologies include blunt trauma, infections, cystic medial necrosis, fibromuscular dysplasia, arteriosclerosis, and congenital abnormalities. The authors report an exceedingly rare case of a dissected external carotid artery pseudoaneurysm in a 26-year-old female patient with neurofibromatosis complicated by preeclampsia at 28-week period of gestation, safely and successfully treated by coil embolization.

Genetic testing for bicuspid aortic valve

Bicuspid aortic valve (BAV) is a congenital defect in which the aortic valve has two rather than three leaflets. In many patients valve function may be normal but valve decompensation may occur due to other associated congenital abnormalities and secondary valve and aortic complications. Decompensation manifests as stenosis or regurgitation and thoracic aortic aneurysm and dissection. Cystic medial necrosis plays an important role in the pathogenesis of BAV. Prevalence of BAV is estimated at 0.5-2.0%. In children, 70-85% of stenotic aortic valves are bicuspid, compared to at least 50% in adults. BAV has autosomal dominant inheritance. This Utility Gene Test was developed on the basis of an analysis of the literature and existing diagnostic protocols. It is useful for confirming diagnosis, as well as for differential diagnosis, couple risk assessment and access to clinical trials.

Genetic diseases of the aorta: aortic diseases associated with bicuspid aortic valves

There is a genetic cause of bicuspid aortic valve. Dilatation of the aortic root and ascending aorta has long been considered genetically determined too and treated accordingly. In recent years, basic research combined with advanced cardiac imaging has made a strong case for another cause of this dilatation: an altered flow profile in the ascending aorta due to the abnormal geometry of the bicuspid valve, leading to an area of altered wall shear stress, which in turn leads to remodelling of the aortic wall, with apoptosis of vascular smooth muscle cells and disruption of media layer as a result. These histological changes, previously referred to as cystic medial necrosis, form the basis of a loss of structural integrity of the aortic wall, which makes it prone to dilatation, dissection, and rupture.

The JCR:LA-cp rat: a novel rodent model of cystic medial necrosis

Although there are multiple rodent models of the metabolic syndrome, very few develop vascular complications. In contrast, the JCR:LA-cp rat develops both metabolic syndrome and early atherosclerosis in predisposed areas. However, the pathology of the normal vessel wall has not been described. We examined JCR:LA control (+/+) or cp/cp rats fed normal chow diet for 6 or 18 mo. JCR:LA-cp rats developed multiple features of advanced cystic medial necrosis including “cysts,” increased collagen formation and proteoglycan deposition around cysts, apoptosis of vascular smooth muscle cells, and spotty medial calcification. These appearances began within 6 mo and were extensive by 18 mo. JCR:LA-cp rats had reduced medial cellularity, increased medial thickness, and vessel hypoxia that was most marked in the adventitia. In conclusion, the normal chow-fed JCR:LA-cp rat represents a novel rodent model of cystic medial necrosis, associated with multiple metabolic abnormalities, vascular smooth muscle cell apoptosis, and vessel hypoxia. NEW & NOTEWORTHY Triggers for cystic medial necrosis (CMN) have been difficult to study due to lack of animal models to recapitulate the pathologies seen in humans. Our study is the first description of CMN in the rat. Thus the JCR:LA-cp rat represents a useful model to investigate the underlying molecular changes leading to the development of CMN.