Familial arteriopathy with associated pulmonary and systemic arterial stenoses

Supravalvar aortic stenosis: Imaging characteristics and associations on multidetector computed tomography angiography

AIM

To evaluate the imaging features and associations in patients with supravalvar aortic stenosis on multidetector computed tomography (CT) angiography.

MATERIALS AND METHODS

We retrospectively reviewed all CT angiography studies performed for evaluation of congenital heart diseases at our institution through the period from January 2014 to June 2020. Cases with supravalvar aortic stenosis were identified and classified as syndromic and nonsyndromic based on history, physical examination, and relevant investigations. The type and extent of vascular involvement and associated cardiovascular abnormalities were characterized.

RESULTS

Supravalvar aortic stenosis was identified in 26/3926 (0.66%) patients (22 males and 4 females; Age range: 2 months to 20 years). Discrete stenosis was seen in 14/26 (53.8%) patients, while diffuse involvement of the ascending aorta to varying degrees was seen in the remaining 12 (46.2%) patients. About 15/26 (57.7%) patients had pulmonary involvement at some level, namely, infundibular, valvar, supravalvar, or peripheral pulmonic stenosis while 15/26 (57.7%) patients had coronary arterial involvement either in the form of stenosis, occlusion, or ectasia. Aortic valvular abnormality including thickening, partial fusion, and adhesion of leaflet edges to the sinutubular junction causing reduced coronary inflow was seen in 15/26 (57.7%) patients. Associated ventricular septal defect, patent ductus arteriosus, and mitral valvular prolapse were seen in four (15.4%), five (19.2%), and two (7.7%) patients respectively.

CONCLUSION

Supravalvar aortic stenosis is a rare abnormality showing associated pulmonary arterial involvement, coronary arterial involvement, aortic valvular abnormalities, and associated congenital cardiac defects in the majority of cases, which may influence surgical outcomes.

Elastin, arterial mechanics, and cardiovascular disease

Large, elastic arteries are composed of cells and a specialized extracellular matrix that provides reversible elasticity and strength. Elastin is the matrix protein responsible for this reversible elasticity that reduces the workload on the heart and dampens pulsatile flow in distal arteries. Here, we summarize the elastin protein biochemistry, self-association behavior, cross-linking process, and multistep elastic fiber assembly that provide large arteries with their unique mechanical properties. We present measures of passive arterial mechanics that depend on elastic fiber amounts and integrity such as the Windkessel effect, structural and material stiffness, and energy storage. We discuss supravalvular aortic stenosis and autosomal dominant cutis laxa-1, which are genetic disorders caused by mutations in the elastin gene. We present mouse models of supravalvular aortic stenosis, autosomal dominant cutis laxa-1, and graded elastin amounts that have been invaluable for understanding the role of elastin in arterial mechanics and cardiovascular disease. We summarize acquired diseases associated with elastic fiber defects, including hypertension and arterial stiffness, diabetes, obesity, atherosclerosis, calcification, and aneurysms and dissections. We mention animal models that have helped delineate the role of elastic fiber defects in these acquired diseases. We briefly summarize challenges and recent advances in generating functional elastic fibers in tissue-engineered arteries. We conclude with suggestions for future research and opportunities for therapeutic intervention in genetic and acquired elastinopathies.

Elastin insufficiency predisposes to elevated pulmonary circulatory pressures through changes in elastic artery structure

Elastin is a major structural component of large elastic arteries and a principal determinant of arterial biomechanical properties. Elastin loss-of-function mutations in humans have been linked to the autosomal-dominant disease supravalvular aortic stenosis, which is characterized by stenotic lesions in both the systemic and pulmonary circulations. To better understand how elastin insufficiency influences the pulmonary circulation, we evaluated pulmonary cardiovascular physiology in a unique set of transgenic and knockout mice with graded vascular elastin dosage (range 45-120% of wild type). The central pulmonary arteries of elastin-insufficient mice had smaller internal diameters (P < 0.0001), thinner walls (P = 0.002), and increased opening angles (P = 0.002) compared with wild-type controls. Pulmonary circulatory pressures, measured by right ventricular catheterization, were significantly elevated in elastin-insufficient mice (P < 0.0001) and showed an inverse correlation with elastin level. Although elastin-insufficient animals exhibited mild to moderate right ventricular hypertrophy (P = 0.0001) and intrapulmonary vascular remodeling, the changes were less than expected, given the high right ventricular pressures, and were attenuated compared with those seen in hypoxia-induced models of pulmonary arterial hypertension. The absence of extensive pathological cardiac remodeling at the high pressures in these animals suggests a developmental adaptation designed to maintain right-sided cardiac output in a vascular system with altered elastin content.

Neonatal Williams syndrome presenting as an isolated supravalvular pulmonary stenosis

An infant with normal facies and none of the extracardiac anomalies usually associated with Williams syndrome presented at birth with an echocardiographic pattern of supravalvular pulmonary stenosis and displastic pulmonary valve. A clinical reappraisal was planned at 3 months of age, but the girl died suddenly at home at 2 months of age. At autopsy, both ventricles were hypertrophic, and the valves showed mild dysplasia. The walls of the great arteries were thick, with a "washed leather" consistency, but there was no gross evidence of discrete stenosis. The histologic mosaic appearance of the media of the great arteries, due to elastosis and extreme disarray of the elastic lamellae, prompted a postmortem diagnosis of supravalvar aortic stenosis and suggested a diagnosis of Williams syndrome, which was subsequently confirmed by fluorescence in situ hybridization. Pediatricians and pathologists should be alerted that Williams syndrome in the newborn may present as an isolated supravalvular pulmonary stenosis, whereas supravalvular aortic stenosis becomes clinically significant only a few months later.

Repair of a complex aortic arch anomaly associated with cutaneous hemangioma

Aortic coarctation and cutaneous hemangioma is a rare association. We describe the case of a neonate with abnormal looping of the aortic arch associated with hemangioma of the head and neck who underwent complex surgical repair without cardiopulmonary bypass.

Congenital supravalvar aortic stenosis: a simple lesion?

The underlying cause of congenital supravalvular aortic stenosis (SVAS) has recently been identified as a loss-of function mutation of the elastin gene on chromosome 7q11.23, resulting in an obstructive arteriopathy of varying severity, which is most prominent at the aortic sinutubular junction. The generalized nature of the disease explains the frequent association with stenoses of systemic and pulmonary arteries. Furthermore, localization of the supravalvular stenosis at the level of the commissures of the aortic valve has important implications for both aortic valve function and coronary circulation. This review summarizes the recent advances with regard to the pathogenesis of SVAS and describes the multitude of clinically relevant pathologic features other that the mere 'supra-aortic' narrowing that have important implications for surgical therapy.

Severe tortuosity and stenosis of the systemic, pulmonary and coronary vessels in 12 patients with similar phenotypic features: a new syndrome?

We describe what is, to the best of our knowledge, a previously unreported association in patients with similar facial features, skin and joint laxity, of lengthening and tortuosity of systemic, pulmonary and coronary vessels. We evaluated 12 patients with similar phenotypes, from eight different families. Detailed echocardiographic and angiographic evaluations were performed in all, and biopsies of the skin in seven. All patients have elongated facies, prominent ears, micrognathia and laxity of their joints. Angiographic pictures showed a varying degree of lengthening and tortuosity of systemic, pulmonary, and coronary arteries. Pulsatile carotid arteries formed cervical masses in 2 patients, and three had severe renal arterial stenoses. All showed varying degrees of branch and peripheral pulmonary arterial stenosis, necessitating placement of stents in six. Biopsy of the skin proved normal in all seven patients studied, thus excluding cutis laxa, Ehlers-Danlos and Marfan syndromes. The constellation of abnormalities suggests a genetic syndrome of connective tissue etiology. Further genetic studies, and gene mapping, are underway.

Surgery for bilateral outflow tract obstruction in elastin arteriopathy

OBJECTIVE

A number of patients with Williams syndrome or other forms of elastin arteriopathy have stenoses of pulmonary arteries in addition to supravalvular aortic stenosis. We sought to investigate the effect of the degree of pulmonary arterial stenosis on the prognosis after an operation for supravalvular aortic stenosis to help define the optimal treatment strategy for patients with severe forms of elastin arteriopathy.

METHODS

Between 1960 and 1999, 33 patients underwent operations for supravalvular aortic stenosis while having significant stenoses of the pulmonary arteries. We retrospectively reviewed patient charts, obtained current follow-up information, and determined risk factors for survival and reoperation.

RESULTS

Fifteen patients with moderate right-sided obstructions (confirmed by pulmonary artery Z-scores and right ventricular/descending aortic pressure ratio) underwent operations for supravalvular aortic stenosis only. Eighteen patients had more severe right-sided obstructions and underwent surgical relief of pulmonary arterial stenoses or right ventricular outflow tract obstruction in addition to operations for supravalvular aortic stenosis. Eight patients had undergone preoperative balloon dilations of stenotic pulmonary arteries. There were 6 early deaths and 1 late death in our series. Survival at 10 and 20 years was 76% (70% confidence interval, 68%-84%) and freedom from reintervention was 59% (70% confidence interval, 46%-71%) at 10 years and 49% (70% confidence interval, 35%-62%) at 20 years. Multivariate analysis revealed that patients with a right ventricular/descending aortic pressure ratio of 1.0 or more were at higher risk for reintervention but not for death.

CONCLUSIONS

Surgical treatment of pulmonary artery obstructions in elastin arteriopathy is palliative but, in conjunction with balloon dilation of peripheral pulmonary arteries, offers good long-term survival to patients with the severest form of elastin arteriopathy.

The aortic root in supravalvular aortic stenosis: the potential surgical relevance of morphologic findings

OBJECTIVE

We aimed to elucidate the structural basis of supravalvular aortic stenosis in the context of its surgical repair.

METHODS

We examined retrospectively the angiograms and echocardiograms of 37 patients and compared them with those of control groups. Additionally, we studied 8 pathologic specimens.

RESULTS

Partial adhesion of the leaflets to the stenosing ridge was observed in 54% of the cases and the leaflets were thickened and less mobile in 30%. Forty-five percent of the angiograms showed evidence of coronary orificial stenosis. The sinuses of Valsalva were significantly enlarged in 75% of the cases. Changes in dimensions of the aortic root were demonstrated more clearly by angiography than by echocardiography. In all anatomic specimens, a marked redundancy of the leaflets was observed and quantified.

CONCLUSIONS

Our data demonstrate that the entire valvular apparatus is always affected by the so-called supravalvular stenosis. Anatomic restoration of the aortic root should ideally take into account all of the deformed components by enlarging all three sinuses of Valsalva at the sinotubular junction.

Congenital stenotic arteriopathy with medial dysplasia of aorta, pulmonary artery, and their major branches

This report describes the morphological findings in a young child with congenital stenotic arteriopathy who died suddenly following arteriography. Hyperplasia of all of the medial components had produced severe thickening of the wall of the aorta (mean number of lamellar units = 133 in the thoracic aorta and 125 in the abdominal aorta), the pulmonary artery, and their major proximal branches, resulting in significant luminal narrowing. Bilateral renal artery stenosis, attributable mainly to intimal longitudinal smooth muscle hyperplasia associated with fibroelastosis, was the cause of her systemic hypertension. The left ventricle showed healed subendocardial infarction.

Autosomal dominant supravalvular aortic stenosis: large three-generation family

Supravalvular aortic stenosis (SVAS) can be inherited as an isolated autosomal dominant trait or can be a component manifestation of the Williams syndrome. Some consider the Williams syndrome to be due to more severe expression of the gene defect that causes isolated SVAS. We describe a family with isolated SVAS that is the largest thoroughly studied family with this disorder to our knowledge; no patients in this family had Williams syndrome. Five members of this family were reported by Lewis et al. (Dis Chest 55:372-379, 1969). We reevaluated this family and now include examinations of the parents, additional sibs and children of the original 5 patients. Twenty relatives had physical and echocardiographic examinations. In addition, information from outside sources was obtained on 7 relatives not personally evaluated. The SVAS showed marked variability of expression and was not associated with mental retardation or with the facial manifestations of Williams syndrome. We think that previous reports of Williams syndrome reputedly occurring within the same family as isolated autosomal dominant SVAS were inadequately documented. Based on our family and review of the literature, we suggest that isolated SVAS and Williams syndrome represent clinically distinct entities.

Familial supravalvular aortic stenosis: a genetic study

Supravalvular aortic stenosis (McKusick 18550) is a rare hereditary condition with autosomal dominant transmission. However, the available data have been limited to small family groups which do not allow the definition of the degree of penetrance of the disease. The present study describes a large family with a high frequency of supravalvular aortic stenosis including five generations and 80 subjects, the largest family group with this disease studied so far. The study was carried out prospectively in 66 subjects (clinical examination, ECG, M mode and two dimensional echocardiography). In 14 subjects available data were examined retrospectively. In 10 patients cardiac catheterisation was performed (prospective study in eight). The disease was present in 36 (45%) of the 80 subjects investigated, on the basis of clinical, echocardiographic, and haemodynamic (when available) criteria. The disease was found to be severe in eight cases (22%), moderate in six cases (17%), mild in 13 (36%), and undefined in eight (22%) patients. In one case (3%), multiple pulmonary stenoses were noted in the absence of supravalvular aortic stenosis. Genetic analysis of these data shows, for the first time, the degree of penetrance of the supravalvular aortic stenosis trait (K = 0.86) and confirms that it is transmitted with incomplete penetrance and variable expressivity.

Congenital stenotic arteriopathy with medial dysplasia

An unusual, uniformly stenotic arteriopathy involving the aorta and its major branches, the pulmonary trunk, and the left and right pulmonary arteries was found in association with a persistent common atrioventricular canal in an otherwise normal stillborn female infant. The uniform arterial thickening was due to hyperplastic medial elastic laminae, which were in an orderly arrangement in the inner two thirds but dysplastic in the outer third of the media of the arteries.

Radiologic case presentation

Images

Familial supravalvular aortic stenosis. Report of a large family and review of the literature

Familial supravalvular aortic stenosis has been recognized as a distinct syndrome. A large family with five proven cases and a review of the literature on familial supravalvular aortic stenosis are presented. The diagnosis was substantiated in all 63 cases by cardiac catheterization, surgery, or postmortem examination.

Surgical correction of diffuse supravalvular aortic stenosis involving the branches of the aortic arch

A case of diffuse supravalvular aortic stenosis including the ascending aorta, the aortic arch, and its branches is presented. The operative procedure employed for correction is presented in detail and discussed. This is the first report of the successful surgical treatment of this type of malformation.

Supravalvular aortic stenosis. Echocardiographic features

The echocardiographic manifestations of segmental supravalvular aortic stenosis are described in 2 patients. The diagnosis was confirmed by cardiac catheterization in both and at operation in 1. A systematic echocardiographic approach to such patients is described. The characteristic finding in these patients was the narrowing of the diameter of the aortic lumen at the stenotic area just distal to the aortic valve. As the transducer sweeps further cephalad the aortic lumen widens to a normal diameter. In one patient treated surgically, postoperative echogram demonstrated the narrowing to be reduced.

A developmental complex including supravalvular stenosis of the aorta and pulmonary trunk

A developmental complex is described characterized by (1) supravalvular stenosis of the aorta and pulmonary trunk, (2) dysplasia of valves and (3) stenosis of ostia of coronary arteries and branches of the aortic arch. From the four cases described, it is evident that not all of the features of the complex need be present in a given case and, when present, some lesions are not of functional significance. The variations underly the potential for differences in the hemodynamic states of affected subjects.