Familial aorto-cervicocephalic arterial dissections and congenitally bicuspid aortic valve

Prevalence and Outcomes of Bicuspid Aortic Valve in Patients With Aneurysmal Sub-Arachnoid Hemorrhage: A Prospective Neurology Registry Report

Background Intracranial aneurysms are reported in 6%-10% of patients with bicuspid aortic valve (BAV), and routine intracranial aneurysm surveillance has been advocated by some. We assessed the prevalence and features of the most important patient-outcome: aneurysmal sub-arachnoid hemorrhage (aSAH), as compared with controls without aSAH, and tricuspid aortic valve (TAV) with aSAH. Methods and Results Adult patients with accurate diagnosis of aSAH and at least one echocardiogram between 2000 and 2019 were identified from a consecutive prospectively maintained registry of aSAH admissions. Controls without a diagnosis of SAH were age- and sex-matched. BAV prevalence was confirmed echocardiographically. Severity of aSAH was categorized using modified Fisher and World Federation of Neurological Scale. Neurologic outcome was assessed using modified Rankin score. A total 488 aSAH cases and 990 controls were identified and BAV status was confirmed. Prevalence of BAV in patients with aSAH was 1.2% (6/488) versus 3.5% (35/990) in controls, P=0.01. BAV+aSAH were noted to be younger than TAV+aSAH (56±11 versus 68±14; P=0.03) with smaller aneurysms (5±2 versus 7±4; P=0.31). The severity of aSAH was lesser in BAV+aSAH than TAV (modified Fisher grade>2 50% versus 74%; P=0.19, World Federation of Neurological Scale grade>3 17% versus 36%; P=0.43). BAV+aSAH had less severe neurologic disability (modified Rankin score 3%-6 33% versus 49% in TAV; P=0.44) and comparable in-hospital mortality rates (P=0.93). BAV had lower odds for aSAH on multivariate analysis (odds ratio 0.23[CI 0.08-0.65]; P=0.01). Conclusions Prevalence of BAV was 3 times lower in the aSAH registry than in controls without aSAH. BAV+aSAH had clinically smaller aneurysms, clinically smaller bleeds, and better neurologic outcome as compared with TAV+aSAH, which needs to be confirmed in larger studies. These findings argue against routine surveillance for intracranial aneurysms in patients with BAV without aortic coarctation.

Carotid Stiffness Assessment With Ultrafast Ultrasound Imaging in Case of Bicuspid Aortic Valve

AIMS

To compare the carotid stiffness and flow parameters by ultrafast ultrasound imaging (UF), in bicuspid aortic valve (BAV) patients to first-degree relatives (controls).

METHODS

BAV patients (n = 92) and controls (n = 48) were consecutively included at a reference center for BAV. Aortic valve and ascending aorta were evaluated by echocardiography. Common carotid arteries were evaluated by UF with a linear probe. A high frame rate (2,000 frames/s) was used to measure the pulse wave velocity (PWV). The arterial diameter change over the cardiac cycle was obtained by UF-Doppler imaging. This allowed us to measure the distensibility and the maximal rate of systolic distension (MRSD). The wall shear stress (WSS) was measured based on the same acquisitions, by analyzing blood flow velocities close to the carotid walls.

RESULTS

BAV patients had significantly larger aortic diameters (p < 0.001) at the Valsalva sinus and at the tubular ascending aorta but no larger carotid diameters. No significant differences were found in carotid stiffness parameters (distensibility, MRSD, and PWV), even though these patients had a higher aortic stiffness. Carotid stiffness correlated linearly with age and similar slopes were obtained for BAV patients and controls. No difference in carotid WSS was found between BAV patients and controls.

CONCLUSION

Our results clearly show that the carotid stiffness and flow parameters are not altered in case of BAV compared with controls.

The Bicuspid Condition of the Aortic Valve Does Not Alter the Incidence of Accessory Coronary Artery Ostia in Syrian Hamsters (Mesocricetus auratus)

In man and Syrian hamsters (Mesocricetus auratus), the prevalence of anomalies in the origin of the coronary arteries is significantly higher in individuals with bicuspid than with normal aortic valves. In hamsters, the incidence of accessory ostia is similar in individuals with normal and anomalous coronary arteries, all of them possessing a normal (tricuspid) aortic valve. In order to evaluate whether or not the presence of bicuspid aortic valves alters the incidence of accessory ostia, 1,050 hearts from hamsters with bicuspid valves were examined. In 594 of them the coronary arteries were normal. The remaining 456 hearts showed coronary artery anomalies characterized by the absence of any artery arising from the left side of the valve. The incidence of accessory ostia was 3.9% in hamsters with normal coronary arteries and 2.2% in those with anomalous coronary patterns. Overall, 3.1% of the accessory ostia were associated with a septal artery and another 0.2% with a conal artery. These data referring to the bicuspid valves were compared with those already published on normal valves. The results of statistical analyses showed that having a bicuspid aortic valve does not alter the incidence of accessory coronary ostia. In the set of tricuspid and bicuspid valves, the incidence of accessory ostia was significantly lower on the left side than on the right side of the valve. This, together with the fact that in the present animal model the coronary anomalies were characterized by the absence of arteries on the left side of the valve, suggests that the embryonic region corresponding to the left side of the aortic valve primordium is particularly associated with preventing the normal development of coronary vessels.

Prevalence of Intracranial Aneurysms in Patients with Aortic Dissection

BACKGROUND AND PURPOSE

There is an uncertainty about the association between intracranial aneurysms and aortic dissection. We aimed to determine the prevalence of intracranial aneurysms in patients with aortic dissection and evaluate the independent risk factors for the presence of intracranial aneurysms in these patients.

MATERIALS AND METHODS

Seventy-one patients with a confirmed aortic dissection who underwent additional brain imaging were enrolled as the aortic dissection group, and 2118 healthy individuals with brain imaging, as controls. Demographic data were obtained from their medical records, including age, sex, comorbidities, and arch vessel involvement of aortic dissection. Two readers reviewed all brain images independently regarding the presence, morphology, size, and location of intracranial aneurysms. Baseline characteristics were compared between the aortic dissection group and controls by propensity score matching, and logistic regression analysis was performed for independent risk factors for the presence of intracranial aneurysms.

RESULTS

The prevalence of intracranial aneurysms was 12.96% in the aortic dissection group and 1.85% in controls (P = .022). The mean diameter of intracranial aneurysms was significantly larger in the aortic dissection group (5.79 ± 3.26 mm in aortic dissection versus 3.04 ± 1.57 mm in controls; P = .008), and intracranial aneurysms of >7 mm were also more common in the aortic dissection group (28.6% in aortic dissection versus 5.3% in controls, P = .003). On multivariate analysis, arch vessel involvement of aortic dissection was an independent risk factor for the presence of intracranial aneurysms (odds ratio, 6.246; 95% confidence interval, 1.472-26.50; P = .013).

CONCLUSIONS

Patients with aortic dissection have a high prevalence of intracranial aneurysms, and selective screening for brain vessels could be considered in these patients with arch vessel involvement. A further prospective study is needed to demonstrate a substantial prevalence of intracranial aneurysms.

Bicuspid Aortic Valve: a Review with Recommendations for Genetic Counseling

Bicuspid aortic valve (BAV) is the most common congenital heart defect and falls in the spectrum of left-sided heart defects, also known as left ventricular outflow tract obstructive (LVOTO) defects. BAV is often identified in otherwise healthy, asymptomatic individuals, but it is associated with serious long term health risks including progressive aortic valve disease (stenosis or regurgitation) and thoracic aortic aneurysm and dissection. BAV and other LVOTO defects have high heritability. Although recommendations for cardiac screening of BAV in at-risk relatives exist, there are no standard guidelines for providing genetic counseling to patients and families with BAV. This review describes current knowledge of BAV and associated aortopathy and provides guidance to genetic counselors involved in the care of patients and families with these malformations. The heritability of BAV and recommendations for screening are highlighted. While this review focuses specifically on BAV, the principles are applicable to counseling needs for other LVOTO defects.

Proteomics of Ascending Aortic Aneurysm with Bicuspid or Tricuspid Aortic Valve

Bicuspid aortic valve is often associated with lesions of the ascending aorta, which differ histologically from those in tricuspid valve patients. We undertook proteomic analyses to assess differences at the proteome level. Aortic samples were collected from 20 patients undergoing aortic valve and/or ascending aortic replacement; 9 had a bicuspid valve: 5 with aortic aneurysm (diameter > 50 mm) and 4 without dilation; 11 had a tricuspid valve: 6 with aortic aneurysm and 5 without dilation. Patients with histologically proven connective tissue disorders were excluded. Samples were dissected, solubilized, and subjected to 2-dimensional gel electrophoresis. Gel patterns showed an average of 580 protein spots in samples from bicuspid valve patients, and 564 spots in those with tricuspid valves. Comparative analysis revealed a correlation coefficient of 0.93 for protein expression in the bicuspid valve group compared to the tricuspid group. Three protein spots were significantly over-expressed and 4 were significantly down-regulated in the bicuspid group compared to the tricuspid group. The lowest correlation in protein expression was between non-dilated aortic tissues. These differences between aortic tissues of bicuspid and tricuspid valve patients suggest that mechanisms of aortic dilation might differ, at least in part, between such patients.

Surgical repair of aortic dissection 16 years post-Ross procedure

The Ross procedure is an excellent choice for younger patients in need of aortic valve replacement. While patients have benefited from superior survival rates associated with this procedure, complications related to aortic root dilatation and degeneration of the autograft may be encountered later in life. These challenges may be exacerbated in those with underlying connective tissue abnormalities, a phenomenon commonly observed in the bicuspid aortic valve population. In this report, we present the case of a patient who presented with an aortic dissection 16 years after a Ross procedure for aortic insufficiency in the setting of a bicuspid aortic valve, and review the existing literature related to this adverse event.

Notch-dependent EMT is attenuated in patients with aortic aneurysm and bicuspid aortic valve

Bicuspid aortic valve is the most common congenital heart malformation and the reasons for the aortopathies associated with bicuspid aortic valve remain unclear. NOTCH1 mutations are associated with bicuspid aortic valve and have been found in individuals with various left ventricular outflow tract abnormalities. Notch is a key signaling during cardiac valve formation that promotes the endothelial-to-mesenchymal transition. We address the role of Notch signaling in human aortic endothelial cells from patients with bicuspid aortic valve and aortic aneurysm. Aortic endothelial cells were isolated from tissue fragments of bicuspid aortic valve-associated thoracic aortic aneurysm patients and from healthy donors. Endothelial-to-mesenchymal transition was induced by activation of Notch signaling. Effectiveness of the transition was estimated by loss of endothelial and gain of mesenchymal markers by immunocytochemistry and qPCR. We show that aortic endothelial cells from the patients with aortic aneurysm and bicuspid aortic valve have down regulated Notch signaling and fail to activate Notch-dependent endothelial-to-mesenchymal transition in response to its stimulation by different Notch ligands. Our findings support the idea that bicuspid aortic valve and associated aortic aneurysm is associated with dysregulation of the entire Notch signaling pathway independently on the specific gene mutation.

Spontaneous internal carotid artery rupture during neck dissection in osteogenesis imperfecta patient

OBJECTIVE

Several connective tissue disorders are associated with vascular wall abnormalities, including spontaneous dissection of the cervical arteries. Osteogenesis imperfecta (OI) is a hereditary disorder, with rare neurovascular complications, which potentially lead to life-threatening events.

METHODS

We presented a case of spontaneous internal carotid artery (ICA) rupture that occurred in a 52-year-old-woman, suffering from OI type I, and who underwent a bilateral modified radical neck dissection (mRND) plus total thyroidectomy for a T4aN1b thyroid cancer. During mRND, an ICA's spontaneous rupture occurred.

RESULTS

Histopathologic report suggested a structural defect of the arterial wall without cancer infiltration. The patient did not experience any neurologic complications.

DISCUSSION

Head and neck surgeons have to be aware about early clinical recognition of possible cervical vascular abnormalities, in patients with connective tissue disorders, potentially responsible for dramatic vascular rupture during cervical surgical procedures.

Echocardiographic evidence of innate aortopathy in the human intracranial aneurysm

BACKGROUND

Intracranial aneurysm (IA) is significantly more prevalent in patients with coarctation of the aorta or bicuspid aortic valve than in the general population, suggesting a common pathophysiology connecting IA and aortopathy. Here, we analyzed echocardiographic aortic root dimension (ARD) in patients with IA to confirm this possibility.

METHODS

From January 2008 to December 2010, 260 consecutive patients with IA who were admitted to our institution for coil embolization or for acute stroke management and who also underwent echocardiography were enrolled. We hypothesized that patients with large, ruptured, or multiple IAs are more likely to harbor co-prevalent aortopathy as measured by ARD compared to patients with small, isolated, unruptured IAs. Eccentric group was defined as patients aged <55 years with at least one ruptured aneurysm, an aneurysm ≥7 mm in size, or multiple aneurysms; the remainder was classified into a non-eccentric group. Clinical, angiographic, and echocardiographic findings of the two groups were compared.

RESULTS

ARD was significantly larger in the eccentric group than in the non-eccentric group (P = 0.049), and the difference was confirmed by multivariable analysis (P = 0.02). Subgroup analysis of patients aged <55 years showed similar result for ARD (P = 0.03), whereas hypertension was more associated with the non-eccentric group (P = 0.01). In addition, height was inversely related to aneurysm size after adjustment for age, sex, weight, ARD, smoking status, and number of aneurysms (P = 0.004).

CONCLUSIONS

A certain group of IA patients share a common intrinsic wall defect with aortopathy. Shared neural crest cell origin may give rise to this phenomenon.

Hereditary connective tissue diseases in young adult stroke: a comprehensive synthesis

Though the genetic background of ischaemic and haemorrhagic stroke is often polygenetic or multifactorial, it can in some cases result from a monogenic disease, particularly in young adults. Besides arteriopathies and metabolic disorders, several connective tissue diseases can present with stroke. While some of these diseases have been recognized for decades as causes of stroke, such as the vascular Ehlers-Danlos syndrome, others only recently came to attention as being involved in stroke pathogenesis, such as those related to Type IV collagen. This paper discusses each of these connective tissue disorders and their relation with stroke briefly, emphasizing the main clinical features which can lead to their diagnosis.

Cardiac neural crest orchestrates remodeling and functional maturation of mouse semilunar valves

Congenital anomalies of the aortic valve are common and are associated with progressive valvular insufficiency and/or stenosis. In addition, aneurysm, coarctation, and dissection of the ascending aorta and aortic arch are often associated conditions that complicate patient management and increase morbidity and mortality. These associated aortopathies are commonly attributed to turbulent hemodynamic flow through the malformed valve leading to focal defects in the vessel wall. However, numerous surgical and pathological studies have identified widespread cystic medial necrosis and smooth muscle apoptosis throughout the aortic arch in affected patients. Here, we provide experimental evidence for an alternative model to explain the association of aortic vessel and valvular disease. Using mice with primary and secondary cardiac neural crest deficiencies, we have shown that neural crest contribution to the outflow endocardial cushions (the precursors of the semilunar valves) is required for late gestation valvular remodeling, mesenchymal apoptosis, and proper valve architecture. Neural crest was also shown to contribute to the smooth muscle layer of the wall of the ascending aorta and aortic arch. Hence, defects of cardiac neural crest can result in functionally abnormal semilunar valves and concomitant aortic arch artery abnormalities.

Bicuspid aortic valve disease

Bicuspid aortic valve (BAV) disease is the most common congenital cardiac defect. While the BAV can be found in isolation, it is often associated with other congenital cardiac lesions. The most frequent associated finding is dilation of the proximal ascending aorta secondary to abnormalities of the aortic media. Changes in the aortic media are present independent of whether the valve is functionally normal, stenotic, or incompetent. Although symptoms often manifest in adulthood, there is a wide spectrum of presentations ranging from severe disease detected in utero to asymptomatic disease in old age. Complications can include aortic valve stenosis or incompetence, endocarditis, aortic aneurysm formation, and aortic dissection. Despite the potential complications, 2 large contemporary series have demonstrated that life expectancy in adults with BAV disease is not shortened when compared with the general population. Because BAV is a disease of both the valve and the aorta, surgical decision making is more complicated, and many undergoing aortic valve replacement will also need aortic root surgery. With or without surgery, patients with BAV require continued surveillance. Recent studies have improved our understanding of the genetics, the pathobiology, and the clinical course of the disease, but questions are still unanswered. In the future, medical treatment strategies and timing of interventions will likely be refined. This review summarizes our current understanding of the pathology, genetics, and clinical aspects of BAV disease with a focus on BAV disease in adulthood.

Screening for intracranial aneurysms in patients with bicuspid aortic valve

Objective: Bicuspid aortic valve (BAV) is a common congenital heart defect affecting half to 2% of the population. A generalized connective tissue disorder also involving the intracranial arteries has been suspected in this patient population. We therefore screened a group of patients with BAV for the presence of intracranial aneurysms.

Methods: Magnetic resonance angiography or CT angiography of the brain was used in 61 patients with BAV (age, 29–70 years [mean 48 years]) and in 291 controls (28–78 years [mean 56 years]).

Results: Intracranial aneurysms were detected in 6 of 61 patients with BAV (9.8%; 95% confidence interval [CI] 2.4%–17.3%). This was significantly higher than in the control population (3/291 [1.1%; 95% CI 0%–2.2%]) (p = 0.0012). Female sex (p = 0.02) and advanced age (p = 0.003), risk factors for intracranial aneurysm development, were more common in the control population than among the patients with a BAV. No significant differences were detected in age, sex, smoking, arterial hypertension, alcohol use, aortic diameter, or frequency of aortic coarctation between BAV patients with and without intracranial aneurysms.

Conclusion: In this case-control study, the frequency of intracranial aneurysms among our bicuspid aortic valve patient population was significantly higher than in the control population.

Basal and oxidative stress-induced expression of metallothionein is decreased in ascending aortic aneurysms of bicuspid aortic valve patients

BACKGROUND

Bicuspid aortic valve (BAV) is a heritable condition that has been linked by an unknown mechanism to a predisposition for ascending aortic aneurysm. Matrix metalloproteinases have been implicated in this predisposition. Metallothionein is a poorly characterized, metal-binding protein that regulates matrix metalloproteinases and is an antioxidant known to be upregulated under oxidative stress.

METHODS AND RESULTS

To determine putative factors involved in the pathogenesis of aortic aneurysm in BAV patients, our first goal was to identify genes that are dysregulated in ascending aortic aneurysms of BAV patients compared with tricuspid aortic valve patients and nondiseased (control) donors. By microarray analysis (22,000 probe sets), 110 dysregulated genes were identified in BAV compared with tricuspid aortic valve patients and control donors; 8 were genes of the metallothionein family. Metallothionein gene expression and protein expression were significantly lower in aortic tissue and cultured aortic smooth muscle cells from BAV patients compared with control subjects. Matrix metalloproteinase-9 expression was increased in BAV aortic samples relative to controls. BAV aorta was more susceptible to oxidative stress, and induction of metallothionein under oxidative stress was reduced in BAV patients compared with control subjects.

CONCLUSIONS

These results demonstrate dysregulated metallothionein expression in ascending aortic smooth muscle cells of BAV patients that may contribute to an inadequate response to oxidative stress and provoke aneurysm formation. We hypothesize that metallothionein plays a pivotal role in the response of ascending aortic smooth muscle cells to oxidative stress cues normally involved in the maintenance of the extracellular matrix, including the regulation of matrix metalloproteinase expression.

The dilated aorta in patients with congenital cardiac defects

Many patients with congenital cardiac disease are at risk for progressive aortic dilation. The mechanisms underlying aortic dilation in this patient cohort are described, and the similarities to the pathophysiologic alterations seen in Marfan syndrome are highlighted. Indications for treatment are discussed.

The genetics of congenital heart disease: a review of recent developments

PURPOSE OF REVIEW

As our understanding of the molecular regulation of cardiac development has progressed, an increasing number of genes that cause congenital heart disease when mutated are being identified. This review focuses on the progress made during the past year.

RECENT FINDINGS

After PTPN11 was identified as a Noonan syndrome disease gene, additional discoveries have made clear that mutations in other genes along the RAS signaling pathway can cause a spectrum of syndromes and possibly isolated congenital heart disease. Similarly, alterations of genes in other signaling and transcriptional pathways may contribute to the development of atrial septal defects and bicuspid aortic valves. Recently identified disease genes for syndromes associated with congenital heart disease are also reviewed. Finally, the possibility that somatic mosaicism may contribute to the development of congenital heart disease is discussed.

SUMMARY

The recent knowledge about the molecular genetic causes of congenital heart disease is reviewed. In many instances, these gene discoveries are being rapidly translated into meaningful genetic testing, which is improving the diagnosis and prognostication for congenital heart disease in isolation or in the context of a syndrome. Ultimately, genetic information will be necessary for planning care as well as clinical research.

Genetic Basis of Thoracic Aortic Aneurysms and Dissections: Potential Relevance to Abdominal Aortic Aneurysms

Ascending thoracic aortic aneurysms leading to type A dissections (TAAD) have long been known to occur in association with a genetic syndrome such as Marfan syndrome (MFS). More recently, TAAD has also been demonstrated to occur as an autosomal dominant disorder in the absence of syndromic features, termed familial TAAD. Familial TAAD demonstrates genetic heterogeneity, and linkage studies have identified TAAD loci at 5q13-14 (TAAD1), 11q23 (FAA1), 3p24-25 (TAAD2), and 16p12.2-13.13. The genetic heterogeneity of TAAD is reflected by variation in disease in terms of the age of onset, progression, penetrance, and association with additional cardiac and vascular features. The underlying genetic heterogeneity of TAAD is reflected in the phenotypic variation associated with familial TAAD with respect to age of onset, progression, penetrance, and association with additional cardiac and vascular features. Mutations in the TGFBR2 gene have been identified as the cause of disease linked to the 3p24-25 locus, implicating dysregulation of TGF-beta signaling in TAAD. Mutations in myosin heavy chain (MYH11), a smooth muscle cell-specific contractile protein, have been identified in familial TAAD associated with patent ductus arteriosus (PDA) linked to 16p12.2-12.13. The identification of these novel disease pathways has led to new directions for future research addressing the pathology and treatment of TAAD.

Ascending aorta dilatation in aortic valve disease: morphological analysis of medial changes

We investigated whether and how the severity of medial degeneration lesions varies along the circumference of the dilated intrapericardial aorta. Two groups of aortic wall specimens, respectively harvested in the convexity and concavity of ascending aorta in 72 patients undergoing surgery for dilatation of the intrapericardial aorta associated with aortic valve disease, were separately sent for pathology, morphometry, and ultrastructural examination. Cystic medial necrosis, fibrosis, and elastic fiber fragmentation were classified into three degrees of severity; their mean degree and morphometric findings in the convexity and in the concavity specimens were compared by paired t-test. Correlation between echocardiographic degree of aortic dilatation and severity of medial degeneration was assessed separately for each of the two groups of specimens. Morphologically, medial degeneration was found in all cases; a higher mean degree was found in the convexity group (2.39 +/- 0.58 vs 1.44 +/- 0.65 in the concavity group; P < 0.001). At morphometry normal smooth muscle cells in the convexity specimens were significantly reduced (P = 0.007); the length (P = 0.012) and number (P = 0.009) of elastic fibers reduced and increased, respectively. Moreover, in the convexity specimens a significantly smaller amount of smooth muscle cells and an increase of immunohistochemical labeling of apoptosis-associated proteins in the subintimal layer of the media was noticed. Correlation between aortic ratio and medial degeneration degree was significant in the convexity group (P < 0.001), but not in the concavity group (P = 0.249). Scanning electron microscopy analysis confirmed morphological results and allowed us to better distinguish the early pathological cavities from the microvessels, which were in the outer media in normal aorta and ubiquitous in aortitis or atherosclerosis. Electron transmission microscopy analysis showed changes in the extracellular matrix and smooth muscle cells, and these changes increased from the intima to the adventitial layer of the media. In dilated intrapericardial aorta, medial degeneration changes and expression of apoptosis-associated proteins are more marked in the ascending aorta convexity, likely due to hemodynamic stress asymmetry. Ultrastructural findings allow us to distinguish the early medial changes not yet evident on light microscopy.

Aortic dilatation in patients with bicuspid aortic valve

The association of a bicuspid aortic valve (BAV) with abnormalities of the proximal thoracic aorta, including dilatation, aneurysm and dissection, has been previously described, leading to the hypothesis of a common underlying developmental defect involving the aortic valve and the aortic wall. Consequently, any patient with BAV should receive a careful assessment not only of the valve function, but also of the aortic root and the ascending aorta. Dilatation of the proximal thoracic aorta is a common finding in patients with BAV and is believed to be related to aortic rupture and dissection. Because progressive dilatation can occur, careful long-term surveillance of the aortic dimensions is required. Prophylactic surgical repair of the dilated aorta should be recommended more aggressively for patients with BAV than for those with a tricuspid aortic valve. However, the optimal timing of aortic surgery in BAV patients remains uncertain because of the limited data available on the natural history of asymptomatic aortic dilatation.

Post-stenotic aortic dilatation

Aortic stenosis is the most common valvular heart disease affecting up to 4% of the elderly population. It can be associated with dilatation of the ascending aorta and subsequent dissection. Post-stenotic dilatation is seen in patients with AS and/or aortic regurgitation, patients with a haemodynamically normal bicuspid aortic valve and following aortic valve replacement. Controversy exists as to whether to replace the aortic root and ascending aorta at the time of aortic valve replacement, an operation that potentially carries a higher morbidity and mortality. The aetiology of post-stenotic aortic dilatation remains controversial. It may be due to haemodynamic factors caused by a stenotic valve, involving high velocity and turbulent flow downstream of the stenosis, or due to intrinsic pathology of the aortic wall. This may involve an abnormality in the process of extracellular matrix remodelling in the aortic wall including inadequate synthesis, degradation and transport of extracellular matrix proteins. This article reviews the aetiology, pathology and management of patients with post-stenotic aortic dilatation.

Solitary coronary ostium in the aorta in Syrian hamsters. A morphological study of 130 cases

BACKGROUND

Solitary coronary ostium in the aorta (SCOA) is a rare anomaly, the pathogenesis of which remains uncertain. The lack of an animal model is one of the reasons why little understanding of this question has been gained. The aim was to examine the coronary distribution patterns associated with SCOA in laboratory inbred Syrian hamsters.

METHODS

The study concerns 130 cases detected in a database consisting of 1,202 internal casts of the heart, great arterial trunks, and coronary arteries.

RESULTS

In 21 (16.2%) cases, the solitary ostium was located in the left aortic sinus. In a further 58 (44.6%) cases, it was in the right aortic sinus. In the remaining 51 (39.2%) cases, the ostium was in the right side of the ventral aortic sinus of a bicuspid aortic valve. The distribution patterns were classified according to the location of the solitary ostium and the presence, or absence, and course of the main coronary arterial vessels. Overall, 14 categories were established, 10 of which had their counterpart in man.

CONCLUSIONS

The findings reported substantiate the use of the present inbred Syrian hamsters for further studying the morphogenesis of the SCOA. The results of a statistical analysis indicate that when a sole coronary ostium becomes established in the aortic root, the development of the resultant anomalous coronary arterial tree tends to happen through preferential pathways. In addition, they indicate that the branching mode of the coronary tree and the condition of the aortic valve are independent traits.

Genetic basis of thoracic aortic aneurysms and aortic dissections

Ascending thoracic aortic aneurysms leading to type A dissections (TAAD) can occur in association with a genetic syndrome, such as Marfan syndrome (MFS), or as an autosomal dominant disorder in the absence of syndromic features, termed familial TAAD. Familial TAAD demonstrates genetic heterogeneity, and linkage studies have identified three TAAD loci at 5q13-14 (TAAD1), 11q23 (FAA1), and 3p24-25 (TAAD2). The underlying genetic heterogeneity of TAAD is reflected in the phenotypic variation associated with familial TAAD with respect to age of onset, progression, penetrance, and association with additional cardiac and vascular features. Recently, mutations in the TGFBR2 gene have been identified as the cause of disease linked to the TAAD2 locus, supporting the hypothesis that dysregulation of TGFbeta signaling is a mechanism leading to aneurysms and dissections. The recent identification of the TGFbeta pathway as a key target in the molecular pathogenesis of TAAD has opened new avenues for future genetic and therapeutic research.

Indications, Timing, and Prognosis of Operative Repair of Aortic Dissections

Since the first description of aortic dissection in the 1700s, the understanding and treatment of this catastrophic disease has evolved. Aortic dissections are identified as a tear in the aortic intima and inner layer of the media that allows for blood flow within the aortic wall. The area of the vessel involved determines its classification. The classification, in turn, helps to predict outcomes, which allows for appropriate treatment planning. The goal of this article is to outline the operative indications and timing for Stanford type A and type B dissections, based on prior reported data and our own clinical experience with 176 patients treated surgically at the Yale Center for Thoracic Aortic Disease. With this data we will revisit the importance of looking at each patient individually to devise an appropriate operative plan, with the knowledge that treatment for type A dissections is operative and treatment for type B dissections is medical unless patients present with actual or impending rupture, malperfusion, or failure of medical management.

Spontaneous dissection of carotid and coronary arteries

The authors report a case of spontaneous dissection of both carotid arteries, followed by spontaneous dissection of the left anterior descending coronary artery after a few days. No major abnormalities of collagen production were found. This case may be underlain by a dysplasia of common precursors of the carotid and coronary walls.

Bilateral spontaneous vertebral artery dissection: management during labor and vaginal delivery

We report the successful management of labor and delivery of a parturient with a history of spontaneous bilateral vertebral artery dissection. We also outline the reasons why the obstetric anesthetist should be aware of this condition as well as other cranio-cervical dissections.

A syndrome of spontaneous cerebral and cervical artery dissections with angiolipomatosis. Report of two cases

A primary or systemic arteriopathy is frequently suspected in patients with spontaneous cerebral or cervical artery dissections. The authors report on two patients with such dissections accompanied by angiolipomatosis, a previously unreported association, and propose a common developmental defect in these patients. A 50-year-old man with subcutaneous angiolipomatosis developed painful monocular blindness. Angiography studies revealed a spontaneous extracranial internal carotid artery (ICA) dissection and an ipsilateral fusiform intracranial ICA aneurysm. The ICA dissection was treated with aspirin, and after 6 months a craniotomy was performed. The aneurysm was found to be fusiform; it involved the entire supraclinoid portion of the ICA, and was wrapped with cotton. A 49-year-old man with a congenitally bicuspid aortic valve and subcutaneous angiolipomatosis developed posterior neck pain. Magnetic resonance imaging and angiography demonstrated a fusiform distal vertebral artery aneurysm. A craniotomy was performed and the aneurysm was found to incorporate the posterior inferior cerebellar artery as well as a perforating artery: the lesion was wrapped cotton. The tunica media of the arteries of the head and neck as well as the aortic valvular cusps are derived from neural crest cells, and angiolipomatosis has been associated with tumors of neural crest derivation. These associations indicate that a neural crest disorder may be the underlying abnormality in these patients.

Ascending aortic aneurysm associated with bicuspid and tricuspid aortic valve: involvement and clinical relevance of smooth muscle cell apoptosis and expression of cell death-initiating proteins

OBJECTIVE

There is relationship between a dilated ascending aorta and a bicuspid aortic valve. Controversy exists concerning techniques available for surgical restoration of the functional and anatomical integrity of the aortic root. The present study was undertaken to define the histopathologic and molecular biologic condition of ascending aortic aneurysms associated with bicuspid (BAV) or tricuspid aortic valve (TAV) and the relationship to valve sparing or pulmonary autograft procedures.

METHODS

Aortic aneurysm wall specimens from 20 patients (10 BAV; 10 TAV) undergoing elective repair and normal aortic tissues from organ donors (n=5) were analysed for patterns of smooth muscle cells (SMCs) and infiltrating leukocytes (immunohistochemistry), apoptosis (in situ end-labelling of DNA-fragments (TUNEL)), and expression of the death-promoting proteins perforin, Fas, and FasLigand (Immunoblotting).

RESULTS

Segments from aneurysms exhibited a distinct pattern of medial destruction, elastic fragmentation, and disorientation with rarefication of SMCs. BAV wall segments contained more cells bearing markers of apoptosis than TAV specimens whereas normal aorta displayed only few apoptotic cells (P<0.05). TUNEL showed higher levels of DNA fragmentation in BAV than in TAV, and double immunostaining identified SMCs as the principal cell type displaying fragmented DNA. Immunohistochemistry confirmed expression of death-promoting mediators by infiltrating lymphocytes, and Western blotting documented their presence in BAV and TAV aneurysmal tissue, with the greatest increases seen in specimens from aneurysms associated with BAV.

CONCLUSIONS

There is evidence for a molecular link between SMC apoptosis initiated by infiltration and local signal expression of immune cells and weakening of the aortic wall being more prevalent in patients with BAV. Our findings may suggest a mechanism responsible for aneurysm formation of the aorta and aortic dilatation after autograft root or sinus remodelling procedures.

Morphometric analysis of aortic media in patients with bicuspid and tricuspid aortic valve

BACKGROUND

Patients with bicuspid aortic valves tend to develop dilatation of the ascending aorta. The aim of this study was to analyze whether or not there is any histologic difference in the aortic media of patients with a bicuspid aortic valve or a tricuspid aortic valve.

METHODS

A morphometric analysis of the wall of the ascending aorta was performed in 107 patients with bicuspid aortic valves undergoing aortic valve operations. The thickness of the elastic lamellae of the aortic media and the distances between the elastic lamellae were measured with the use of an image analysis system. The histologic specimens of the ascending aorta from 61 surgical patients with tricuspid aortic valve disease served as a control.

RESULTS

The patients with bicuspid aortic valves had thinner elastic lamellae of the aortic media (2.71 +/- 0.23 microm) of the ascending aortic wall than the patients with tricuspid aortic valve disease (2.83 +/- 0.23 microm) (p = 0.006). The patients with bicuspid aortic valves also had greater distances between the elastic lamellae (27.21 +/- 8.69 microm) of the ascending aortic wall in comparison with the patients with tricuspid aortic valve disease (24.34 +/- 5.32 microm) (p = 0.033). There was no difference in the total thickness of the aortic media between the groups (p = 0.62).

CONCLUSIONS

Patients with a bicuspid aortic valve had thinner elastic lamellae of the aortic media and greater distances between the elastic lamellae than patients with a tricuspid aortic valve.

The treatment of spontaneous carotid and vertebral artery dissections

Spontaneous dissections of the carotid and vertebral arteries in the neck are a common cause of stroke in young and middle-aged people. Moreover, they are increasingly recognized as the cause of a wide variety of other, more subtle, neurologic signs and symptoms. The cause of these arterial dissections largely remains unexplained but probably involves a combination of genetic and environmental factors. Magnetic resonance imaging has largely surpassed angiography as the imaging study of choice. The treatment of carotid and vertebral artery dissections is based on rather incomplete evidence. Anticoagulation with heparin followed by warfarin remains the treatment of choice in most major medical centers and is supported by the demonstration of emboli as the most common cause of stroke in these patients. The burgeoning interest in endovascular techniques has resulted in many patients being treated for carotid and vertebral artery dissections with percutaneous angioplasty and stent deployment. Although the treatment of dissections is generally well tolerated and the radiographic results are impressive, most dissections heal spontaneously and the associated aneurysms never rupture and rarely cause delayed ischemic symptoms. Surgical treatment of dissections, consisting of an in situ interposition graft or extracranial-intracranial bypass, is indicated only for those patients with persistent symptoms refractory to maximal medical therapy who are not candidates for endovascular treatment.

Risk factors for arterial ischemic stroke in children

Since early recurrence occurs in at least 10% of patients presenting with their first stroke in childhood in the reported series, the search for modifiable risk factors should be a priority. Risk factors for stroke in adults include hypertension, diabetes, and smoking, as well as cardiac disease and sickle cell anemia; asymptomatic cerebrovascular disease and transient ischemic events may predict stroke in this age group. The investigation of a child with a stroke has traditionally focused on finding a single cause rather than looking for risk factors to which the patient may be exposed life long. Approximately half of children presenting with stroke have a known predisposing condition, but some have unexpected pathologies such as primary cerebrovascular disease associated with congenital heart anomalies, or may have modifiable risk factors such as hypertension associated with sickle cell disease. The literature on children presenting with initially unexplained (cryptogenic) stroke suggests that there is a daunting list of possible causes, but since the series have mainly been small, it has been difficult to evaluate the relative importance of the reported associations. This paper reviews the literature on congenital, genetic, and acquired risk factors for stroke in childhood, and includes data from the large series of patients seen at Great Ormond Street Hospital over the past 10 years. The majority have arteriographic abnormalities and there is little evidence for asymptomatic cardiac disease. Genetic predisposition, trauma, infection, and nutritional deficiencies appear to be important, although case-control studies will be required to prove causation. Appropriate screening for modifiable risk factors may lead to prevention of recurrence in some patients. In the long term, an understanding of the multiple etiologies of childhood cerebrovascular disease and ischemic stroke may lead to primary prevention in this age group, and perhaps in adults.

Natural history, pathogenesis, and etiology of thoracic aortic aneurysms and dissections

The natural history of thoracic aortic aneurysms and dissections is diverse, reflecting a broad spectrum of etiologies which include increasing aortic size, hypertension, and genetic factors. The pathogenesis is related to defects or degeneration in structural integrity of the adventitia, not the media, which is required for aneurysm formation. The ascending and descending aorta appear to have separate underlying disease processor that lead to a weakened vessel wall and an increased susceptibility for dissection. Etiologic factors for aortic aneurysms and dissections are multifactorial, reflecting genetic, environmental, and physiologic influences.

Histologic abnormalities of the ascending aorta and pulmonary trunk in patients with bicuspid aortic valve disease: clinical relevance to the ross procedure

OBJECTIVE

Bicuspid aortic valve disease is often associated with dilation of the aortic root and ascending aorta. This study examines the histologic features of the ascending aorta and main pulmonary artery of patients with and without aortic valve disease.

METHODS

Samples from ascending aorta and main pulmonary artery were obtained at the time of the operation from 20 patients with bicuspid aortic valve and 11 patients with tricuspid aortic valve disease. In addition, samples were also obtained from autopsy cases with normal aortic valve. The histologic changes were graded from 1 to 3 according to severity of degenerative changes.

RESULTS

In the ascending aorta, the severity of cystic medial necrosis (P =.001), elastic fragmentation (P =.002), and changes in the smooth muscle cell orientation (P =.002) were significantly more severe in patients with bicuspid than in those with tricuspid aortic valve disease. In the pulmonary trunk specimens, those 3 histologic features were also significantly more severe in patients with bicuspid than those with tricuspid valves (P =.001, P =.01, and P =.04, respectively). Seventy-five percent of patients with bicuspid aortic valve disease had grade 3 degenerative changes, whereas only 14% of those patients with tricuspid aortic valve disease had similar degrees of degenerative changes.

CONCLUSION

Patients with bicuspid aortic valve disease have more severe degenerative changes in the media of the ascending aorta and main pulmonary artery than patients with tricuspid aortic valve disease. These findings may explain root and ascending aortic dilation in patients with bicuspid aortic valve disease and pulmonary autograft dilation in certain patients after the Ross procedure.

Persistent dissection of carotid artery in patients operated on for type A acute aortic dissection--carotid ultrasound follow-up

Over a period of 5 years, 124 patients were operated on at the National Institute of Cardiology in Warsaw for acute aortic dissection, 27 of whom died. The 97 patients discharged from the hospital were included in the present analysis. The age of the patients ranged from 25 to 73 years with a mean of 50+/-10 years. Ultrasound examination of carotid arteries was performed with the patient lying on his back using a Toshiba 340A color Doppler system with a linear array probe of 7.5 MHz. Of the 97 patients examined, 15 (15%) had a dissection of at least one of the common carotid arteries (CCA). Two had Marfan syndrome. In 11 patients the dissection involved the right common carotid artery and in four it involved both the left and right common carotid arteries. The flow in the true lumen of CCA and ICA was preserved in all patients and the degree of narrowing ranged from 30 to -70%. Only one of the 15 patients with CCA dissection had an ipsilateral neurological deficit which was already present before the aortic aneurysm operation. Ultrasound follow-up was performed in all patients with the CCA dissection found on first examination. The mean duration of follow-up was 21 months. In 14 patients the degree and extent of the dissection as well as the narrowing of the true lumen was comparable, and in one patient the false channel closed spontaneously. During follow-up there were no new major neurological events despite the persistence of the CCA dissection with different degrees of narrowing of the true lumen. Doppler ultrasound examination of the carotid arteries can supply additional information about the extent of the dissection, and help to assess the flow in the persisting 'double channel' common carotid artery during the follow-up of patients.

Aortic root dilatation in young men with normally functioning bicuspid aortic valves

OBJECTIVE

To evaluate the dimensions of the aortic root in a selected population of young males with isolated normally functioning bicuspid aortic valve.

DESIGN AND SETTING

Echocardiographic and Doppler evaluation of conscripts with bicuspid aortic valve at the time of military pre-enrolment screening in two military hospitals.

SUBJECTS AND METHODS

66 consecutive young men with a normally functioning bicuspid aortic valve were studied to assess aortic size at four aortic levels: annulus, sinuses of Valsalva, supra-aortic ridge, and proximal ascending aorta; 70 consecutive normal young subjects, matched for age and body surface area, were used as controls.

RESULTS

In men with a bicuspid aortic valve, the diameter of the aortic root was significantly larger than in controls at the sinuses (3.16 (0.37) v 2.87 (0.31) cm, p < 0.001), at the supra-aortic ridge (2.64 (0.46) v 2.47 (0.28) cm, p = 0.01), and at the level of the proximal ascending aorta (3.12 (0.48) v 2.69 (0.28) cm, p < 0.001). The prevalence of aortic root dilatation was 7.5% at the annulus (5/66), 19.6% at the sinuses (13/66), 15% at the supra-aortic ridge (10/66), and 43.9% at the ascending aorta (29/66); 32 subjects (48%) had aortic root dimensions comparable with controls, while 34 (52%) had definitely abnormal aortic root dimensions.

CONCLUSIONS

Aortic root enlargement in people with a bicuspid aortic valve occurs independently of haemodynamic abnormalities, age, and body size. However, there appear to be different subgroups of young adults with bicuspid aortic valves, one of which is characterised by aortic dilatation, possibly caused by a congenital abnormality of the aortic wall.

[Cervical artery dissection: recent data physiopathologic hypotheses]

INTRODUCTION

Cervicocranial arterial dissection is a major cause of cerebral infarction in young subjects. Traumatic and infectious factors are frequently suspected to be at the origin of cervicocranial artery dissection. However, they are usually too minor or too common to explain the vessel wall split-off. Underlying arteriopathy predisposing to dissections is therefore often suspected.

CURRENT KNOWLEDGE AND KEY POINTS

The hypothesis of an underlying arteriopathy is based in certain cases on either the discovery of hereditary connective tissue disorders (or secondary signs of these diseases) or their frequent association with vascular and cardiac morphological abnormalities, thus suggesting extracellular matrix abnormalities. Current histological and biochemical data do not suggest the existence of a unique form of the disease but rather indicate the presence of various matrix abnormalities that could involve one of the fibrillar components or its enzymatic regulation.

FUTURE PROSPECTS AND PROJECTS

Classification of dissections according to the various vascular wall alterations would therefore permit to better define recurrence and familial risks and to improve overall management of the patients.

Cervical artery dissection is associated with widened aortic root diameter

OBJECTIVE

Dissection of the internal carotid and vertebral arteries is a well recognized cause of stroke, especially in the middle-aged. The exact etiology of this condition is controversial. According to one theory there is an underlying vasculopathy originating from disturbed development of the neural crest. The neural crest gives rise to several tissues, including the tunica media of large cervical arteries and the outflow tract of the heart. We attempted to test the theory that developmental abnormality at the level of the neural crest may play a role in dissection of the large cervical arteries.

METHODS

We designed a retrospective case control study. By means of transthoracic echocardiography we measured the aortic root diameter in a group of patients with radiographically determined dissection of at least one large artery in the neck. The results were compared to a control group.

RESULTS

In comparison to age matched controls, male patients were found to have a significantly larger aortic root. Although a similar trend was apparent in females, the difference between the patient and control group of females was not statistically significant.

CONCLUSIONS

Patients with cervical artery dissections may have other abnormalities in other organs arising from the neural crest. A larger prospective clinical study and further research are needed to establish a firm link between dissection of the cervical arteries and abnormalities in other organs.

Seasonal pattern of spontaneous cervical artery dissection

OBJECT

The etiology of spontaneous cervical artery dissection is poorly understood; however, it may involve genetic and environmental factors. The purpose of this study was to determine whether seasonality of spontaneous cervical artery dissection exists.

METHODS

The seasonal pattern of spontaneous cervical artery dissection was analyzed in a group of 200 consecutive patients (104 females and 96 males with a mean age of 44.9 years) who were evaluated using the Rayleigh test during the period from 1970 to 1990. The majority of patients resided in the midwestern section of the United States, where large seasonal fluctuations in climate occur. A circannual periodicity was found in the frequency of spontaneous cervical artery dissections with a peak occurring in October (p < 0.02). The seasonal variation was substantial, with approximately 58% more patients suffering a cervical artery dissection during autumn than during other seasons.

CONCLUSIONS

A seasonal pattern of spontaneous cervical artery dissection exists with a peak occurring in October. The cause of the seasonality remains to be explained; however, weather- or infectious disease-related factors may provide etiological leads.