Histopathologic findings in ascending aortas from individuals with Loeys-Dietz syndrome (LDS)

Cerebral arteriopathies of childhood and stroke - A focus on systemic arteriopathies and pediatric fibromuscular dysplasia (FMD)

Systemic vascular involvement in children with cerebral arteriopathies is increasingly recognized and often highly morbid. Fibromuscular dysplasia (FMD) represents a cerebral arteriopathy with systemic involvement, commonly affecting the renal and carotid arteries. In adults, FMD diagnosis and classification typically relies on angiographic features, like the 'string-of-beads' appearance, following exclusion of other diseases. Pediatric FMD (pFMD) is considered equivalent to adult FMD although robust evidence for similarities is lacking. We conducted a comprehensive literature review on pFMD and revealed inherent differences between pediatric and adult-onset FMD across various domains including epidemiology, natural history, histopathophysiology, clinical, and radiological features. Although focal arterial lesions are often described in children with FMD, the radiological appearance of 'string-of-beads' is highly nonspecific in children. Furthermore, children predominantly exhibit intimal-type fibroplasia, common in other childhood monogenic arteriopathies. Our findings lend support to the notion that pFMD broadly reflects an undefined heterogenous group of monogenic systemic medium-or-large vessel steno-occlusive arteriopathies rather than a single entity. Recognizing the challenges in categorizing complex morphologies of cerebral arteriopathy using current classifications, we propose a novel term for describing children with cerebral and systemic vascular involvement: 'cerebral and systemic arteriopathy of childhood' (CSA-c). This term aims to streamline patient categorization and, when coupled with advanced vascular imaging and high-throughput genomics, will enhance our comprehension of etiology, and accelerate mechanism-targeted therapeutic developments. Lastly, in light of the high morbidity in children with cerebral and systemic arteriopathies, we suggest that investigating for systemic vascular involvement is important in children with cerebral arteriopathies.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Genetic Basis, New Diagnostic Approaches, and Updated Therapeutic Strategies of the Syndromic Aortic Diseases: Marfan, Loeys-Dietz, and Vascular Ehlers-Danlos Syndrome

Syndromic aortic diseases (SADs) encompass various pathological manifestations affecting the aorta caused by known genetic factors, such as aneurysms, dissections, and ruptures. However, the genetic mutation underlying aortic pathology also gives rise to clinical manifestations affecting other vessels and systems. As a consequence, the main syndromes currently identified as Marfan, Loeys-Dietz, and vascular Ehlers-Danlos are characterized by a complex clinical picture. In this contribution, we provide an overview of the genetic mutations currently identified in order to have a better understanding of the pathogenic mechanisms. Moreover, an update is presented on the basis of the most recent diagnostic criteria, which enable an early diagnosis. Finally, therapeutic strategies are proposed with the goal of improving the rates of patient survival and the quality of life of those affected by these SADs.

Association Between Genetic Diagnosis and Clinical Outcomes in Patients With Heritable Thoracic Aortic Disease

Background Differences in the clinical course of heritable thoracic aortic disease based on the disease-causing gene have not been fully evaluated. To clarify the clinical relevance of causative genes in heritable thoracic aortic disease, we assessed the clinical course of patients categorized based on genetic diagnosis. Methods and Results We investigated cardiovascular events and mortality in 518 genetically diagnosed patients in 4 groups: Group 1, FBN1 (n=344); Group 2, TGFBR1, TGFBR2, SMAD3, or TGFB2 (n=74); Group 3, COL3A1 (n=60); and Group 4, ACTA2 or MYH11 (n=40). The median age at the first cardiovascular event ranged from 30.0 to 35.5 years (P=0.36). Patients with gene variants related to transforming growth factor-β signaling had a significantly higher rate of subsequent events than those with FBN1 variants (adjusted hazard ratio, 2.33 [95% CI, 1.60-3.38]; P<0.001). Regarding the incidence of aortic dissection, there were no significant differences among the 4 groups in male patients (36.3%, 34.3%, 21.4%, and 54.2%, respectively; P=0.06). Female patients with COL3A1 variants had a significantly lower incidence than female patients in the other 3 groups (34.2%, 59.0%, 3.1%, and 43.8%, respectively; P<0.001). Conclusions Gene variants related to transforming growth factor-β signaling are associated with a higher incidence of subsequent cardiovascular events than FBN1 variants. COL3A1 variants might be related to a lower incidence of aortic dissection than other gene variants in women only. Identifying the genetic background of patients with heritable thoracic aortic disease is important for determining appropriate treatment.

Coronary Artery Disease Risk Gene PRDM16 is Preferentially Expressed in Vascular Smooth Muscle Cells and a Potential Novel Regulator of Smooth Muscle Homeostasis

Objective

Vascular smooth muscle cells (VSMCs) are the primary contractile component of blood vessels and can undergo phenotypic switching from a contractile to a synthetic phenotype in vascular diseases such as coronary artery disease (CAD). This process leads to decreased expression of SMC lineage genes and increased proliferative, migratory and secretory abilities that drive disease progression. Super-enhancers (SE) and occupied transcription factors are believed to drive expression of genes that maintain cell identify and homeostasis. The goal of this study is to identify novel regulator of VSMC homeostasis by screening for SE-regulated transcription factors in arterial tissues.

Approach and Results

We characterized human artery SEs by analyzing the enhancer histone mark H3K27ac ChIP-seq data of multiple arterial tissues. We unexpectedly discovered the transcription factor PRDM16, a GWAS identified CAD risk gene with previously well-documented roles in brown adipocytes but with an unknown function in vascular disease progression, is enriched with artery-specific SEs. Further analysis of public bulk RNA-seq and scRNA-seq datasets, as well as qRT-PCR and Western blotting analysis, demonstrated that PRDM16 is preferentially expressed in arterial tissues and in contractile VSMCs but not in visceral SMCs, and down-regulated in phenotypically modulated VSMCs. To explore the function of Prdm16 in vivo, we generated Prdm16 SMC-specific knockout mice and performed histological and bulk RNA-Seq analysis of aortic tissues. SMC-deficiency of Prdm16 does not affect the aortic morphology but significantly alters expression of many CAD risk genes and genes involved in VSMC phenotypic modulation. Specifically, Prdm16 negatively regulates the expression of Tgfb2 that encodes for an upstream ligand of TGF-β signaling pathway, potentially through binding to the promoter region of Tgfb2 . These transcriptomic changes likely disrupt VSMC homeostasis and predispose VSMCs to a disease state.

Conclusions

Our results suggest that the CAD risk gene PRDM16 is preferentially expressed in VSMCs and is a novel regulator of VSMC homeostasis. Future studies are warranted to investigate its role in VSMCs under pathological conditions such as atherosclerosis.

Thoracolumbar Scoliosis in Pediatric Patients With Loeys-Dietz Syndrome: A Case Series

Background Loeys-Dietz syndrome (LDS) is a genetic connective tissue disorder that predominantly affects cardiovascular, skeletal, and craniofacial structures. Associated thoracolumbar scoliosis in LDS can be challenging to manage, though other etiologies of pediatric scoliosis have better-defined management guidelines. We examined our institutional experience regarding the treatment of pediatric patients with LDS and scoliosis. Methodology In this retrospective study, all patients seen at our pediatric tertiary care center from 2004 through 2018 with a diagnosis of LDS were reviewed, and those with radiographic diagnoses of scoliosis (full-length scoliosis X-rays) were included. Demographic, clinical, and radiographic parameters were collected, and management strategies were reported. Results A total of 39 LDS patients whose ages ranged between seven and 13 years were identified. A total of nine patients were radiographically diagnosed with scoliosis, but three patients were excluded due to incomplete medical records, leaving six patients. The median age at scoliosis diagnosis was 11.5 years, with a median follow-up of 51 months. Two patients were successfully managed with observation (average initial Cobb angle (CA): 14°, average final CA: 20.5°). Two were braced, one successfully (initial CA: 15°, final CA: 30°) and one with a progressive disease requiring surgery (initial CA: 40°, final CA: 58°). Of the two who were offered surgical correction, one underwent surgery with a durable correction of spinal deformity (CA: 33° to 19°). One patient underwent a recent correction of aortic root dilatation and was not a candidate for scoliosis surgery. Conclusions Principles of adolescent idiopathic scoliosis management such as bracing for CA of 20-50° and surgery for CA of >50° can be applied to LDS patients with good outcomes. This augments our understanding of the treatment algorithm for pediatric patients with LDS.

The genetic basis of thoracic aortic disease: The future of aneurysm classification?

The expansion in the repertoire of genes linked to thoracic aortic aneurysms (TAA) has revolutionised our understanding of the disease process. The clinical benefits of such progress are numerous, particularly helping our understanding of non-syndromic hereditary causes of TAA (HTAAD) and further refinement in the subclassification of disease. Furthermore, the understanding of aortic biomechanics and mechanical homeostasis has been significantly informed by the discovery of deleterious mutations and their effect on aortic phenotype. The drawbacks in genetic testing in TAA lie with the inability to translate genotype to accurate prognostication in the risk of thoracic aortic dissection (TAD), which is a life-threatening condition. Under current guidelines, there are no metrics by which those at risk for dissection with normal aortic diameters may undergo preventive surgery. Future research lies with more advanced genetic diagnosis of HTAAD and investigation of the diverse pathways involved in its pathophysiology, which will i) serve to improve our understanding of the underlying mechanisms, ii) improve guidelines for treatment and iii) prevent complications for HTAAD and sporadic aortopathies.

Multiple deep femoral artery aneurysms with Loeys-Dietz syndrome

A 60-year-old man with Loeys-Dietz syndrome (LDS) underwent surgery for multiple left deep femoral artery aneurysms (DFAAs). An intraoperative graft replacement was performed from the common femoral artery to the distal DFAAs; the superficial femoral artery was sutured to the graft. DFAAs in association with LDS and the occurrence of multiple DFAAs are rare. To the best of our knowledge, no studies have reported their coexistence. Graft replacement was decided as the optimal treatment for our patient. However, treatment should be considered on a patient-by-patient basis. Therefore, a lower limb arterial examination should accompany the screening of patients with LDS.

Isolated aneurysmal disease as an underestimated finding in individuals with JAG1 pathogenic variants

Pathogenic variants in JAG1 are known to cause Alagille syndrome (ALGS), a disorder that primarily affects the liver, lung, kidney, and skeleton. Whereas cardiac symptoms are also frequently observed in ALGS, thoracic aortic aneurysms have only been reported sporadically in postmortem autopsies. We here report two families with segregating JAG1 variants that present with isolated aneurysmal disease, as well as the first histological evaluation of aortic aneurysm tissue of a JAG1 variant carrier. Our observations shed more light on the pathomechanisms behind aneurysm formation in JAG1 variant harboring individuals and underline the importance of cardiovascular imaging in the clinical follow-up of such individuals.

The Genetics and Typical Traits of Thoracic Aortic Aneurysm and Dissection

Genetic predisposition and risk factors such as hypertension and smoking can instigate the development of thoracic aortic aneurysm (TAA), which can lead to highly lethal aortic wall dissection and/or rupture. Monogenic defects in multiple genes involved in the elastin-contractile unit and the TGFβ signaling pathway have been associated with TAA in recent years, along with several genetic modifiers and risk-conferring polymorphisms. Advances in omics technology have also provided significant insights into the processes behind aortic wall degeneration: inflammation, epigenetics, vascular smooth muscle phenotype change and depletion, reactive oxygen species generation, mitochondrial dysfunction, and angiotensin signaling dysregulation. These recent advances and findings might pave the way for a therapy that is capable of stopping and perhaps even reversing aneurysm progression.

Different ascending aortic phenotypes with similar mutations in 2 patients with Loeys-Dietz syndrome type 2

Our goal was to present 2 infants with confirmed Loeys-Dietz syndrome. The missense mutations in exon 7 of the TGFBR2 gene are only 5 codons apart (c.1597T>C and c.1582C>G). Phenotypically, the aneurysms of the ascending aorta were restricted to different segments of the aorta: the suprajunctional segment in 1 patient and the aortic root in another. These cases highlight the complexity of signaling pathways and gene expression in the pathogenesis of aortic aneurysms.

Prevalence of Intracranial Aneurysms in Hereditary Hemorrhagic Telangiectasia: Report from a Single Reference Center

BACKGROUND AND PURPOSE

Neurologic manifestations in hereditary hemorrhagic telangiectasia include an increased incidence of brain abscesses and ischemic strokes due to paradoxic embolization in addition to a wide spectrum of symptoms and complications due to typical brain vascular malformations. Intracranial aneurysms are not part of this brain vascular malformation spectrum. The aim of this study was to determine their prevalence in patients with hereditary hemorrhagic telangiectasia.

MATERIALS AND METHODS

This was a single-center, retrospective study. Adult patients from the institutional Hereditary Hemorrhagic Telangiectasia registry with a definitive diagnosis of hereditary hemorrhagic telangiectasia and an available report or angiographic imaging study were included and reviewed to determine the intracranial aneurysm prevalence. In addition, the morphologic characteristics of intracranial aneurysms and possible associated risk factors were collected.

RESULTS

Two hundred twenty-eight patients were analyzed. Thirty-seven aneurysms in 33 patients (14.5%; 95% CI, 9.9%-19%) were found. The median diameter of intracranial aneurysms was 3.2 mm (interquartile range, 2.6-4.4 mm). No association between intracranial aneurysm and sex, age, or genetic background was noted. There were no subarachnoid hemorrhagic events due to intracranial aneurysm rupture.

CONCLUSIONS

Due to the high prevalence of intracranial aneurysms in adult patients with hereditary hemorrhagic telangiectasia, further studies regarding bleeding risks and monitoring should be addressed.

Increased intracranial arterial tortuosity is associated with worse cardiovascular outcome in patients with Loeys-Dietz syndrome

The aim of our study was to evaluate the association between intracranial arterial tortuosity and cardiovascular outcome in patients with Loeys-Dietz syndrome (LDS). We performed a retrospective analysis of all patients with genetically confirmed LDS who underwent at least one brain MRA at our institution (n = 32); demographic and clinical features were evaluated in relation to the tortuosity of intracranial arteries as measured by tortuosity index (TI), which was calculated using the formula: [(centerline length) / (straight-line length)-1] × 100. Receiver operating characteristic curve analysis for intracranial TI and the binary end point of aortic surgery showed vertebrobasilar TI (VBTI) to be the best classifier among the examined arterial segments (AUC = 0.822). Patients with higher VBTI showed a greater incidence of aortic surgery (p < 0.001) and underwent more surgical and endovascular procedures (p = 0.006), with a higher rate of operations (p = 0.002). Kaplan-Meier analysis showed a significantly longer surgery-free survival in patients with lower arterial tortuosity (p < 0.001). At multivariate analysis, higher VBTI was associated with an increased risk of surgery (p < 0.001), which was independent of gene mutation and patient age. Increased VBTI is a marker of adverse cardiovascular outcome in patients with LDS, which can be easily measured on brain MRA, and may be useful in the management of this heterogeneous patient population.

Neurovascular Syndromes

Patients with cerebrovascular syndromes are at risk for additional concerns associated with their syndrome. A wide variety of syndromes are associated with cerebrovascular diseases. Multidisciplinary care is helpful to ensure comprehensive evaluation and management. Precise diagnosis and appreciation for the underlying syndrome is critical for effective cerebrovascular and broader care. This text focuses on these conditions with a focus on underlying pathophysiology and associated genetics, presentation, diagnosis, and management of each disease.

Rare Neurovascular Diseases in Korea: Classification and Related Genetic Variants

Rare neurovascular diseases (RNVDs) have not been well-recognized in Korea. They involve the central nervous system and greatly affect the patients' lives. However, these diseases are difficult to diagnose and treat due to their rarity and incurability. We established a list of RNVDs by referring to the previous literature and databases worldwide to better understand the diseases and their current management status. We categorized 68 RNVDs based on their pathophysiology and clinical manifestations and estimated the prevalence of each disease in Korea. Recent advances in genetic, molecular, and developmental research have enabled further understanding of these RNVDs. Herein, we review each disease, while considering its classification based on updated pathologic mechanisms, and discuss the management status of RNVD in Korea.

The Contribution of Glycosaminoglycans/Proteoglycans to Aortic Mechanics in Health and Disease: A Critical Review

While elastin and collagen have received a lot of attention as major contributors to aortic biomechanics, glycosaminoglycans (GAGs) and proteoglycans (PGs) recently emerged as additional key players whose roles must be better elucidated if one hopes to predict aortic ruptures caused by aneurysms and dissections more reliably. GAGs are highly negatively charged polysaccharide molecules that exist in the extracellular matrix (ECM) of the arterial wall. In this critical review, we summarize the current understanding of the contributions of GAGs/PGs to the biomechanics of the normal aortic wall, as well as in the case of aortic diseases such as aneurysms and dissections. Specifically, we describe the fundamental swelling behavior of GAGs/PGs and discuss their contributions to residual stresses and aortic stiffness, thereby highlighting the importance of taking these polyanionic molecules into account in mathematical and numerical models of the aorta. We suggest specific lines of investigation to further the acquisition of experimental data to complement simulations and solidify our current understanding. We underscore different potential roles of GAGs/PGs in thoracic aortic aneurysm (TAAD) and abdominal aortic aneurysm (AAA). Namely, we report findings according to which the accumulation of GAGs/PGs in TAAD causes stress concentrations which may be sufficient to initiate and propagate delamination. On the other hand, there seems to be no clear indication of a relationship between the marked reduction in GAG/PG content and the stiffening and weakening of the aortic wall in AAA.

Transforming Growth Factor-β and the Renin-Angiotensin System in Syndromic Thoracic Aortic Aneurysms: Implications for Treatment

Thoracic aortic aneurysms (TAAs) are permanent pathological dilatations of the thoracic aorta, which can lead to life-threatening complications, such as aortic dissection and rupture. TAAs frequently occur in a syndromic form in individuals with an underlying genetic predisposition, such as Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). Increasing evidence supports an important role for transforming growth factor-β (TGF-β) and the renin-angiotensin system (RAS) in TAA pathology. Eventually, most patients with syndromic TAAs require surgical intervention, as the ability of present medical treatment to attenuate aneurysm growth is limited. Therefore, more effective medical treatment options are urgently needed. Numerous clinical trials investigated the therapeutic potential of angiotensin receptor blockers (ARBs) and β-blockers in patients suffering from syndromic TAAs. This review highlights the contribution of TGF-β signaling, RAS, and impaired mechanosensing abilities of aortic VSMCs in TAA formation. Furthermore, it critically discusses the most recent clinical evidence regarding the possible therapeutic benefit of ARBs and β-blockers in syndromic TAA patients and provides future research perspectives and therapeutic implications.

Loeys-Dietz syndrome associated with a heterozygous mutation in TGFBR2 in a female infant: A case report

Loeys-Dietz syndrome (LDS) is an unusual hereditary connective tissue disease with no clear standard clinical diagnosis. The present report describes a case of an infant diagnosed with LDS at the age of 2 months and 23 days. To the best of our knowledge, this case represents the youngest reported case of LDS in China. Whole exome sequencing revealed a heterozygous variation, c.1441(exon 6)G>A [p.E481k(p.Glu481Lys) (NM_001024847)], located at chr3:30715708 in the transforming growth factor β receptor 2 gene. The patient underwent systematic rehabilitation and standard high-risk infant follow-up. Currently, the overall development of the patient continues to improve. The patient can walk with assistance, stand up on her feet unaided, exhibits improved optical line of sight and both eyes can move up and down, side to side (left and right) and track moving objects. The parents have been advised that a further echocardiogram should be performed as soon as possible and regular follow-up sessions with a cardiovascular specialist are ongoing. LDS diagnosis was confirmed in the patient based on collective findings of skeletal system changes, ocular hypertelorism, ocular exotropia, micrognathia and high-vaulted palate, in combination with a specific pathogenic gene mutation.

Identification of a Pathogenic TGFBR2 Variant in a Patient With Loeys-Dietz Syndrome

Loeys-Dietz syndrome (LDS) is a rare connective tissue genetic disorder that is caused by a pathogenic variant in genes of transforming growth factor (TGF) beta receptor 1 (TGFBR1), TGFBR2, mothers against decapentaplegic homolog 2 (SMAD2), SMAD3, TGFB2, or TGFB3. It is characterized by aggressive vascular pathology, aneurysms, arterial tortuosity, bifid uvula, hypertelorism, and cleft palate. Here we present a 42-year-old female patient with LDS. The patient underwent rapidly progressing artery aneurysms and life-threatening aortic dissection. Spontaneous fracture of the first metatarsal bone was noted in her medical record. Physical examination revealed a delayed wound healing on her left abdomen. Considering these clinical manifestations, we speculated that there was a genetic defect in the connective tissue, which provides strength and flexibility to structures such as bones, skins, ligaments, and blood vessels. Thus, whole exome sequencing (WES) was performed on the proband and revealed a heterozygous missense pathogenic variant (c.1613T > C/p.Val538Ala) in TGFBR2, which was a de novo variant in the proband as confirmed by the segregation analysis in parental samples. Although this variant was discovered and associated with the phenotype of LDS previously, the pathogenicity of the variant had not been confirmed by cellular functional assay yet. To further validate the effects of the variant in vitro, we assessed the canonical TGF-β signaling pathway in mutant cells. Our results showed that the p.Val538Ala variant significantly decreased TGF-β-induced gene transcription and the phosphorylation of Smad2, which were consistent with other pathogenic variants of TGFBR2. In conclusion, this study demonstrates that the p.Val538Ala pathogenic variant in TGFBR2 leads to aberrant TGF-β signaling and LDS in this patient.

Oxidant/Antioxidant Profile in the Thoracic Aneurysm of Patients with the Loeys-Dietz Syndrome

Patients with the Loeys-Dietz syndrome (LDS) have mutations in the TGF-βR1, TGF-βR2, and SMAD3 genes. However, little is known about the redox homeostasis in the thoracic aortic aneurysms (TAA) they develop. Here, we evaluate the oxidant/antioxidant profile in the TAA tissue from LDS patients and compare it with that in nondamaged aortic tissue from control (C) subjects. We evaluate the enzymatic activities of glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD) isoforms, and thioredoxin reductase (TrxR). We also analyze some antioxidants from a nonenzymatic system such as selenium (Se), glutathione (GSH), and total antioxidant capacity (TAC). Oxidative stress markers such as lipid peroxidation and carbonylation, as well as xanthine oxidase (ORX) and nuclear factor erythroid 2-related factor 2 (Nrf2) expressions, were also evaluated. TAA from LDS patients showed a decrease in GSH, Se, TAC, GPx, GST, CAT, and TrxR. The SOD activity and ORX expressions were increased, but the Nrf2 expression was decreased. The results suggest that the redox homeostasis is altered in the TAA from LDS patients, favoring ROS overproduction that contributes to the decrease in GSH and TAC and leads to LPO and carbonylation. The decrease in Se and Nrf2 alters the activity and/or expression of some antioxidant enzymes, thus favoring a positive feedback oxidative background that contributes to the TAA formation.

The complex interplay among atherosclerosis, inflammation, and degeneration in ascending thoracic aortic aneurysms

OBJECTIVE

To assess the histopathological findings of a large series of ascending thoracic aortic aneurysm (TAA) surgical specimens applying the updated classification on noninflammatory degenerative and inflammatory aortic diseases proposed by the Association for European Cardiovascular Pathology and the Society for Cardiovascular Pathology clinicopathological correlations.

METHODS

A total of 255 patients surgically treated for ascending TAA were enrolled. Surgical ascending aorta specimens were examined.

RESULTS

The histopathological substrate of ascending TAAs was mainly degenerative (67.5%), but with a remarkable prevalence of atherosclerotic lesions (18.8%) and aortitis (13.7%). Degenerative patients more frequently had bicuspid aortic valve (37.2%; P = .002). Patients in the atherosclerotic group were older (median age, 69 years; P < .001), more often with a history of hypertension (87.5%; P = .059), hypercholesterolemia (75%; P = .019), diabetes (16.6%; P = .054), current smoking (22.9%; P = .066), and a history of coronary artery disease (18.7%; P = .063). Patients with aortitis represented the older group (median age, 75 years, P < .001), were mostly females (68.6%; P < .001), and had a larger ascending aorta diameter (median, 56 mm; P < .001). Both patients with atherosclerosis and aortitis presented a higher incidence of concomitant abdominal aortic aneurysm (20.8% and 22.8%, respectively; P < .001).

CONCLUSIONS

Although degenerative histopathology is the most frequent substrate in ascending TAA, atherosclerosis and inflammation significantly contribute to the development of chronic aortic thoracic disease.

The Chalice Sign : Characteristic Morphology of the Cervical Carotid Bifurcation in Patients with Loeys-Dietz Syndrome

BACKGROUND AND PURPOSE

Loeys-Dietz syndrome (LDS) is a connective tissue disorder characterized by arterial aneurysms and dissections. This study sought to assess and describe the arterial changes of the cervical arterial vasculature of such patients, with an emphasis on the carotid bifurcation.

MATERIAL AND METHODS

A retrospective review of patients with a known diagnosis of LDS was carried out. The maximum diameters of the external carotid artery (ECA) and internal carotid artery (ICA) origins, common carotid artery (CCA) terminus, maximum transverse and craniocaudal dimensions of the carotid bulb, and bifurcation angle were measured. The presence of a chalice sign was defined as a carotid bifurcation angle of ≥80°. A semi-quantified analysis of vertebral artery tortuosity was completed as well. All measurements were compared to a cohort of age-matched controls.

RESULTS

A total of 21 patients with LDS were included. Compared to normal controls, the presence of a chalice sign had 61.9% sensitivity and 100.0% specificity for LDS if present bilaterally; the sensitivity and specificity of a unilateral chalice sign were 66.7% and 82.3%, respectively. Patients with LDS also had significantly higher rates of a bilateral chalice sign compared to patients with vascular Ehlers-Danlos syndrome (vEDS) (61.9% versus 0%, P <0.0001) and patients with Marfan syndrome (61.9% versus 14.3%, P = 0.001).

CONCLUSION

Patients with LDS have characteristic findings of the cervical arterial vasculature that enables them to be distinguished from normal controls as well as patients with connective tissue diseases, such as Marfan syndrome and vEDS; most notably including marked widening of the carotid bifurcation angle in what is proposed to be named the chalice sign.

Changes in Aortic Wall Thickness at a Site of Entry Tear on Computed Tomography before Development of Acute Aortic Dissection

Objective: To determine if there are changes in the aortic wall before acute aortic dissection (AD) that can be observed on contrast-enhanced computed tomography (CECT). Materials and Methods: Twenty-two patients with AD who underwent CECT before developing AD were retrospectively identified and enrolled as the AD group. Twenty-five consecutive patients who underwent CECT and did not develop AD were enrolled as the control group. In the AD group, the site of entry tear was detected on CECT images; the aortic wall thickness at this site, defined as the dissection-related wall thickness (D-T), was then measured on CECT images acquired before AD. Moreover, the mean thickness of the ascending, thoracic descending, and abdominal aortic walls before AD was defined as the non-dissection-related wall thickness (non-D-T). In the control group, the aortic wall thickness was measured similarly and defined as the control wall thickness (C-T). The D-T, non-D-T, and C-T values were compared using one-way analysis of variance with the Games-Howell pairwise comparison test. Results: The D-T (2.17±0.75 mm) was significantly greater than the non-D-T (1.58±0.22 mm; P<.01) and C-T (1.53±0.15 mm; P<.01). Conclusion: The aortic wall may have become thicker prior to the onset of AD.

Alcohol Consumption and Aortic Root Dilatation: Insights from the Corinthia Study

Aortic diameter and progression to thoracic aortic aneurysm are influenced by several factors. In this study, we investigated the association of alcohol consumption with aortic root and ascending aorta dilatation. In the context of the Corinthia study, we examined 1751 patients with echocardiography. Several demographic and clinical characteristics were recorded. Alcohol consumption was assessed based on a questionnaire of frequency, type, and quantity. Accordingly, patients were categorized as everyday alcohol consumers (EDACs) and as social drinkers (SoD). Everyday alcohol consumers were further categorized to group 1: 0 to 1 drink/d; group 2: 1 to 2 drinks/d; and group 3: ≥3 drinks/d. From the study population, 40% were categorized as EDAC and had an increased aortic root diameter (AoRD) and an elevated AoRD index compared with SoD. Interestingly, there was a stepwise increase in aortic root and ascending aorta diameter according to daily alcohol consumption. Specifically, patients consuming ≥3 drinks of alcohol/d had increased indexed aortic by 1.4 mm/m2 compared with SoD even after adjustment for possible confounders. Daily alcohol consumption is associated with increased aortic root diameter. These findings may have important clinical implications, especially in patients with borderline or dilated aortic root, and merit further investigation.

Computed Tomography of Cardiac Valves: Review

Valvular heart disease is a common clinical problem. Although echocardiography is the standard technique for the noninvasive evaluation of the valves, cardiac CT has evolved to become a useful tool in the evaluation of the cardiac structures as well. Importantly, CT allows for improved quantification of valvular calcification due to its superior spatial resolution. It may improve the detection of small valvular or perivalvular pathology or the characterization of valvular masses and vegetations. This review describes the assessment of normal and diseased heart valves by cardiac CT and discusses its strengths and weaknesses.

Absence of LTBP-3 attenuates the aneurysmal phenotype but not spinal effects on the aorta in Marfan syndrome

Fibrillin-1 is an elastin-associated glycoprotein that contributes to the long-term fatigue resistance of elastic fibers as well as to the bioavailability of transforming growth factor-beta (TGFβ) in arteries. Altered TGFβ bioavailability and/or signaling have been implicated in aneurysm development in Marfan syndrome (MFS), a multi-system condition resulting from mutations to the gene that encodes fibrillin-1. We recently showed that the absence of the latent transforming growth factor-beta binding protein-3 (LTBP-3) in fibrillin-1-deficient mice attenuates the fragmentation of elastic fibers and focal dilatations that are characteristic of aortic root aneurysms in MFS mice, at least to 12 weeks of age. Here, we show further that the absence of LTBP-3 in this MFS mouse model improves the circumferential mechanical properties of the thoracic aorta, which appears to be fundamental in preventing or significantly delaying aneurysm development. Yet, a spinal deformity either remains or is exacerbated in the absence of LTBP-3 and seems to adversely affect the axial mechanical properties of the thoracic aorta, thus decreasing overall vascular function despite the absence of aneurysmal dilatation. Importantly, because of the smaller size of mice lacking LTBP-3, allometric scaling facilitates proper interpretation of aortic dimensions and thus the clinical phenotype. While this study demonstrates that LTBP-3/TGFβ directly affects the biomechanical function of the thoracic aorta, it highlights that spinal deformities in MFS might indirectly and adversely affect the overall aortic phenotype. There is a need, therefore, to consider together the vascular and skeletal effects in this syndromic disease.

Carotid Artery Tortuosity Index Is Associated With the Need for Early Aortic Root Replacement in Patients With Loeys-Dietz Syndrome

OBJECTIVE

This study aimed to determine if carotid arterial tortuosity represents a marker of disease severity in Loeys-Dietz syndrome (LDS).

METHODS

Fifty-four 54 LDS patients (mean age, 17.0 years) who underwent computed tomogram angiography from January 2004 to December 2013 were retrospectively identified. Carotid artery tortuosity index (CATI) was calculated from computed tomogram angiography. Clinical variables were obtained from the medical records. Relationship between CATI and need for aortic root replacement was evaluated with Cox proportional hazard model and Kaplan-Meier analysis.

RESULTS

Higher CATI was associated with the need for aortic root replacement (P < 0.001) in the univariate Cox proportional hazard model. Patients were stratified based on both CATI and aortic root size in Kaplan-Meier analysis, and patients with higher CATI were more likely to require aortic root replacement (P < 0.001) in both aortic root size strata.

CONCLUSION

Increased carotid artery tortuosity is associated with the need for early aortic root replacement in patients with LDS.

Endovascular repair of tortuous recurrent femoral-popliteal aneurysm in a patient with Loeys-Dietz syndrome

Loeys-Dietz syndrome is a rare connective tissue disorder with widespread arterial tortuosity and aneurysms. This syndrome is most notable for its aortic disease, including aortic root dilation and aortic dissection or rupture. Although not as well studied, peripheral artery aneurysms are a prevalent concurrent manifestation and have previously been repaired with both open and endovascular approaches. There are minimal data about the durability and technical considerations of endovascular repair in this disease. We report a case of a patient who developed an extremely tortuous recurrent femoral-popliteal artery aneurysm secondary to aneurysmal degeneration around previously placed stents that was treated with an endovascular approach.

Aortic root and hemiarch replacement in a patient with Loeys-Dietz and hypoplastic left heart syndromes

A 15-year-old patient with hypoplastic left heart syndrome underwent 3-stage palliation by the age of 3 years. He was later diagnosed with Loeys-Dietz syndrome. On follow-up imaging, the neoaorta was dilated at 50 mm in diameter. He underwent aortic root replacement with a composite valve conduit and hemiarch replacement, using a boat-shaped Dacron graft. The uncertainty of how univentricular circulation would tolerate long bypass time steered us away from a total arch replacement. His postoperative recovery was uneventful. Imaging postoperatively demonstrated stable dilatation of the aorta distal to the hemiarch replacement. Considering the risk of reintervention, we elected to monitor the distal aorta. The combination of Loeys-Dietz syndrome and hypoplastic left heart syndrome presents unique challenges, rarely reported in the literature.

Exome Sequencing Identifies Candidate Genetic Modifiers of Syndromic and Familial Thoracic Aortic Aneurysm Severity

Thoracic aortic aneurysm (TAA) is a genetic disease predisposing to aortic dissection. It is important to identify the genetic modifiers controlling penetrance and expressivity to improve clinical prognostication. Exome sequencing was performed in 27 subjects with syndromic or familial TAA presenting with extreme phenotypes (15 with severe TAA; 12 with mild or absent TAA). Family-based analysis of a subset of the cohort identified variants, genes, and pathways segregating with TAA severity among three families. A rare missense variant in ADCK4 (p.Arg63Trp) segregated with mild TAA in each family. Genes and pathways identified in families were further investigated in the entire cohort using the optimal unified sequence kernel association test, finding significance for the gene COL15A1 (p = 0.025) and the retina homeostasis pathway (p = 0.035). Thus, we identified candidate genetic modifiers of TAA severity by exome-based study of extreme phenotypes, which may lead to improved risk stratification and development of new medical therapies.

Loss-of-function mutations in the X-linked biglycan gene cause a severe syndromic form of thoracic aortic aneurysms and dissections

PURPOSE

Thoracic aortic aneurysm and dissection (TAAD) is typically inherited in an autosomal dominant manner, but rare X-linked families have been described. So far, the only known X-linked gene is FLNA, which is associated with the periventricular nodular heterotopia type of Ehlers-Danlos syndrome. However, mutations in this gene explain only a small number of X-linked TAAD families.

METHODS

We performed targeted resequencing of 368 candidate genes in a cohort of 11 molecularly unexplained Marfan probands. Subsequently, Sanger sequencing of BGN in 360 male and 155 female molecularly unexplained TAAD probands was performed.

RESULTS

We found five individuals with loss-of-function mutations in BGN encoding the small leucine-rich proteoglycan biglycan. The clinical phenotype is characterized by early-onset aortic aneurysm and dissection. Other recurrent findings include hypertelorism, pectus deformity, joint hypermobility, contractures, and mild skeletal dysplasia. Fluorescent staining revealed an increase in TGF-β signaling, evidenced by an increase in nuclear pSMAD2 in the aortic wall. Our results are in line with those of prior reports demonstrating that Bgn-deficient male BALB/cA mice die from aortic rupture.

CONCLUSION

In conclusion, BGN gene defects in humans cause an X-linked syndromic form of severe TAAD that is associated with preservation of elastic fibers and increased TGF-β signaling.Genet Med 19 4, 386-395.

Neurovascular manifestations of connective-tissue diseases: A review

Patients with connective tissue diseases are thought to be at a higher risk for a number of cerebrovascular diseases such as intracranial aneurysms, dissections, and acute ischemic strokes. In this report, we aim to understand the prevalence and occurrences of such neurovascular manifestations in four heritable connective tissue disorders: Marfan syndrome, Ehlers-Danlos syndrome, Neurofibromatosis Type 1, and Loeys-Dietz syndrome. We discuss the fact that although there are various case studies reporting neurovascular findings in these connective tissue diseases, there is a general lack of case-control and prospective studies investigating the true prevalence of these findings in these patient populations. Furthermore, the differences observed in the manifestations and histology of such disease pathologies encourages future multi-center registries and studies in better characterizing the pathophysiology, prevalence, and ideal treatment options of neurovascular lesions in patents with connective tissue diseases.

Marfan syndrome associated aortic disease in neonates and children: a clinical-morphologic review

BACKGROUND

Marfan syndrome (MFS) is a multisystem connective tissue disorder that can lead to aortic dilation requiring aortic root replacement. Neonatal MFS (nMFS) is a rare and severe form of MFS compared to classic MFS (cMFS). Aortic root histology in MFS is thought to demonstrate predominantly medial degeneration (MD) of a translamellar mucoid extracellular matrix accumulation (MEMA-T) vs. the intralamellar mucoid extracellular matrix accumulation (MEMA-I) seen in other aortopathies. The objective of this study was to describe the clinical and histopathologic features of nMFS and cMFS patients undergoing aortic root replacement.

METHODS

Children with MFS who underwent aortic root replacement between 2000 and 2012 at a single institution were included. Medical records including clinical details, aortic dimensions (Z scores), and histology including MD type were obtained. Statistics were descriptive with univariate analysis of age at surgery and type of MD.

RESULTS

Eleven patients, 3 (27%) with nMFS, were included. Root dilation at time of surgery was greater in nMFS compared to cMFS (Z=12.8 vs. 7.6, P=.005), and nMFS patients were younger at time of surgery (7.3 vs. 18.8 years, P=.002). Histology in the nMFS group demonstrated MEMA-I in one and no MD in two. In the cMFS group, there were three with MEMA-T, four with MEMA-I, and one with both types.

CONCLUSION

In summary, nMFS has earlier root dilation often in the absence of MD. Both forms of MD were present in our cohort, and there was no correlation between age at surgery and type of MD.

Aortic and Pulmonary Root Aneurysms in a Child With Loeys-Dietz Syndrome

We report the case of an 11-year-old boy with Loeys-Dietz syndrome, with both aortic and pulmonary aneurysms requiring cardiac operation because of progressive valve incompetence resulting from loss of coaptation of the cusps. Arterial medial changes, consisting of disarray of elastic fibers and increased collagen deposition, were observed in surgical specimens from both the aorta and the pulmonary artery of our patient, and the strong pSmad2 nuclear staining of smooth muscle cells of both aortic and pulmonary tunica media are the best evidence of transforming growth factor-β pathway activation in Loeys-Dietz syndrome.

Aortic Aneurysm: Etiopathogenesis and Clinicopathologic Correlations

Aortic aneurysm (AA) is one of the life-threatening aortic diseases, leading to aortic rupture of any cause including atherosclerotic and non-atherosclerotic diseases. AA is diagnosed in a variable proportion of patients with dilated aorta by imaging modality. The etiopathogenesis of AA remains unclear in many aortic diseases. Furthermore, although it may be difficult to explain all phenotypes of patients even if genetic mutation could be identified in some proteins such as smooth muscle cell α-actin (ACTA2), myosin heavy chain 11 (MYH11) or SMAD3, individualized consideration of these factors in each patient is essential on the basis of clinicopathological characteristics.

Aortic complications following pediatric heart transplantation: A case series and review

Aortic complications occur rarely after pediatric orthotopic heart transplantation, but are typically accompanied by catastrophic events. We describe the three cases of major aortic complications in our experience of 329 pediatric heart transplants. This case series and review highlight the important risk factors for aortic complications after heart transplantation.

Consensus statement on surgical pathology of the aorta from the Society for Cardiovascular Pathology and the Association For European Cardiovascular Pathology: II. Noninflammatory degenerative diseases - nomenclature and diagnostic criteria

Surgical aortic specimens are usually examined in Pathology Departments as a result of treatment of aneurysms or dissections. A number of diseases, genetic syndromes (Marfan syndrome, Loeys-Dietz syndrome, etc.), and vasculopathic aging processes involved in vascular injury can cause both distinct and nonspecific histopathologic changes with degeneration of the media as a common denominator. Terminology for these changes has varied over time leading to confusion and inconsistencies. This consensus document has established a revised, unified nomenclature for the variety of noninflammatory degenerative aortic histopathologies seen in such specimens. Older terms such as cystic medial necrosis and medionecrosis are replaced by more technically accurate terms such as mucoid extracellular matrix accumulation (MEMA), elastic fiber fragmentation and/or loss, and smooth muscle cell nuclei loss. A straightforward system of grading is presented to gauge the extent of medial degeneration and synoptic reporting tables are provided. Herein we present a standardized nomenclature that is accessible to general pathologists and useful for future publications describing these entities.

Brain Arterial Diameters as a Risk Factor for Vascular Events

Background

Arterial luminal diameters are routinely used to assess for vascular disease. Although small diameters are typically considered pathological, arterial dilatation has also been associated with disease. We hypothesize that extreme arterial diameters are biomarkers of the risk of vascular events.

Methods and Results

Participants in the Northern Manhattan Study who had a time-of-flight magnetic resonance angiography were included in this analysis (N=1034). A global arterial Z-score, called the brain arterial remodeling (BAR) score, was obtained by averaging the measured diameters within each individual. Individuals with a BAR score <−2 SDs were considered to have the smallest diameters, individuals with a BAR score >−2 and <2 SDs had average diameters, and individuals with a BAR score >2 SDs had the largest diameters. All vascular events were recorded prospectively after the brain magnetic resonance imaging. Spline curves and incidence rates were used to test our hypothesis. The association of the BAR score with death (P=0.001), vascular death (P=0.02), any vascular event (P=0.05), and myocardial infarction (P=0.10) was U-shaped except for ischemic stroke (P=0.74). Consequently, incidence rates for death, vascular death, myocardial infarction, and any vascular event were higher in individuals with the largest diameters, whereas individuals with the smallest diameters had a higher incidence of death, vascular death, any vascular event, and ischemic stroke compared with individuals with average diameters.

Conclusions

The risk of death, vascular death, and any vascular event increased at both extremes of brain arterial diameters. The pathophysiology linking brain arterial remodeling to systemic vascular events needs further research.

Giant vein graft aneurysm complicated by Loeys-Dietz syndrome

Loeys-Dietz syndrome (LDS) is a recently reported autosomal dominant aortic aneurysm syndrome with widespread systemic involvement. Although connective tissue diseases carry a theoretical risk of aneurysmal degeneration in vein grafts, there are no reports of vein graft aneurysm (VGA) in patients with connective tissue disease. We herein report the first case of a giant VGA that was manifested 5 years after the reconstruction of a popliteal artery aneurysm associated with LDS. A pathologic examination of the VGA revealed high proteoglycan deposition and medial degeneration of the diffuse type in the VGA; these findings conformed to LDS.

True extracranial carotid artery aneurysm in a child

Isolated true aneurysm of the extracranial carotid artery is a rare entity in the pediatric population, with nine reported cases found in the literature. Contrary to adult carotid aneurysms, which are often due to atherosclerotic disease, pediatric aneurysms are more likely to be the result of congenital malformations, connective tissue diseases, or systemic inflammatory conditions. We present the case of a 10-year-old boy with an isolated true aneurysm of the internal carotid artery and a review of the literature.