The genetics of aortopathies: Hereditary thoracic aortic aneurysms and dissections

Aortopathies encompass a variety of inherited and acquired pathologies that increase risk of life‐threatening dissection or rupture. Identifying individuals with hereditary thoracic aortic aneurysm and dissection (HTAAD) for longitudinal monitoring, medical therapy, or elective and preventative repair is paramount to reduce risk of cardiovascular‐related mortality and complications from dissection and rupture. Over the past couple of decades, pathogenic variants in numerous genes have been identified in relation to HTAAD. The genetic diagnosis can help stratify patient risk and provide guidance on medical treatment, timing of prophylactic surgical repair, as well as longitudinal surveillance and imaging. Implicated genes and their associated proteins have been found to act on a diverse variety of pathways, cells and structural components linked to transforming growth factor beta (TGF‐β) signaling pathways, disruption of the vascular smooth muscle cell contractile apparatus, and primary disruption of extracellular matrix homeostasis. This review describes relevant genetic variants that may help identify and guide the management of hereditary thoracic aortic aneurysms and dissections.     

Thoracic aortic disease in two patients with juvenile polyposis syndrome and SMAD4 mutations

Dilation or aneurysm of the ascending aorta can progress to acute aortic dissection (Thoracic Aortic Aneurysms and Aortic Dissections, TAAD). Mutations in genes encoding TGF‐β‐related proteins (TGFBR1, TGFBR2, FBN1, and SMAD3) cause syndromic and inherited TAAD. SMAD4 mutations are associated with juvenile polyposis syndrome (JPS) and a combined JPS–hereditary hemorrhagic telangiectasia (HHT) known as JPS–HHT. A family with JPS–HHT was reported to have aortic root dilation and mitral valve abnormalities. We report on two patients with JPS–HHT with SMAD4 mutations associated with thoracic aortic disease. The first patient, an 11‐year‐old boy without Marfan syndrome features, had JPS and an apparently de novo SMAD4 mutation (c.1340_1367dup28). Echocardiography showed mild dilation of the aortic annulus and aortic root, and mild dilation of the sinotubular junction and ascending aorta. Computed tomography confirmed aortic dilation and showed small pulmonary arteriovenous malformations (PAVM). The second patient, a 34‐year‐old woman with colonic polyposis, HHT, and features of Marfan syndrome, had a SMAD4 mutation (c.1245_1248delCAGA). Echocardiography showed mild aortic root dilation. She also had PAVM and hepatic focal nodular hyperplasia. Her family history was significant for polyposis, HHT, thoracic aortic aneurysm, and dissection and skeletal features of Marfan syndrome in her father. These two cases confirm the association of thoracic aortic disease with JPS–HHT resulting from SMAD4 mutations. We propose that the thoracic aorta should be screened in patients with SMAD4 mutations to prevent untimely death from dissection. This report also confirms that SMAD4 mutations predispose to TAAD. © 2012 Wiley Periodicals, Inc.     

GenTAC registry report: Gender differences among individuals with genetically triggered thoracic aortic aneurysm and dissection

Previous data suggest women are at increased risk of death from aortic dissection. Therefore, we analyzed data from the GenTAC registry, the NIH‐sponsored program that collects information about individuals with genetically triggered thoracic aortic aneurysms and cardiovascular conditions. We performed cross‐sectional analyses in adults with Marfan syndrome (MFS), familial thoracic aortic aneurysm or dissection (FTAAD), bicuspid aortic valve (BAV) with thoracic aortic aneurysm or dissection, and subjects under 50 years of age with thoracic aortic aneurysm or dissection (TAAD <50 years). Women comprised 32% of 1,449 subjects and were 21% of subjects with BAV, 34% with FTAAD, 22% with TAAD <50 years, and 47% with MFS. Thoracic aortic dissections occurred with equal gender frequency yet women with BAV had more extensive dissections. Aortic size was smaller in women but was similar after controlling for BSA. Age at operation for aortic valve dysfunction, aneurysm or dissection did not differ by gender. Multivariate analysis (adjusting for age, BSA, hypertension, study site, diabetes, and subgroup diagnoses) showed that women had fewer total aortic surgeries (OR = 0.65, P < 0.01) and were less likely to receive angiotensin converting enzyme inhibitors (ACEi; OR = 0.68, P < 0.05). As in BAV, other genetically triggered aortic diseases such as FTAAD and TAAD <50 are more common in males. In women, decreased prevalence of aortic operations and less treatment with ACEi may be due to their smaller absolute aortic diameters. Longitudinal studies are needed to determine if women are at higher risk for adverse events. © 2013 Wiley Periodicals, Inc.     

Endovascular repair of thoracic aortic aneurysm

A thoracic aortic aneurysm (TAA) is a potentially life-threatening condition with structural weakness of the aortic wall, which can progress to arterial dilatation and rupture. Today, both an increasing awareness of vascular disease and the access to tomographic imaging facilitate the diagnosis of TAA even in an asymptomatic stage. The risk of rupture for untreated aneurysms beyond a diameter of 5.6 cm ranges from 46% to 74% and the two-year mortality rate is greater than 70%, with most deaths resulting from rupture. Treatment options include surgical and non-surgical repair to prevent aneurysm enlargement and rupture. While most cases of ascending aortic involvement are subject to surgical repair (partially with valve-preserving techniques), aneurysm of the distal arch and descending thoracic aorta are amenable to emerging endovascular techniques as an alternative to classic open repair or to a hybrid approach (combining debranching surgery with stent grafting) in an attempt to improve outcomes.     

Cantu syndrome: A longitudinal review of vascular findings in three individuals

Cantu syndrome is a rare autosomal dominant disorder caused by missense variants in ABCC9 and KCNJ8. It is characterized by hypertrichosis, neonatal macrosomia, coarse facial features, and skeletal anomalies. Reported cardiovascular anomalies include cardiomegaly, structural defects, collateral vessels, and rare report of arteriovenous malformation (AVM). Arterial dilation is reported in a few individuals including one with surgical intervention for a thoracic aortic aneurysm. The natural history of this aortopathy including the rate of progression or risk for dissection is unknown and longitudinal patient data is unavailable. We present data from vascular imaging in three individuals with genetically confirmed Cantu syndrome over 3 to 14 years of follow‐up. All patients had generally stable aortic dilation, which did not reach the surgical threshold, including one individual followed closely through pregnancy. In adulthood, one individual had a maximum ascending aortic measurement of 4.2 cm. Two pediatric patients had aortic root or ascending z‐scores of approximately +3. A large asymptomatic pelvic AVM was identified in one individual on head‐pelvis MRI. While the data reported in these individuals is reassuring regarding the risk for progressive disease, further data from additional individuals with Cantu syndrome is needed to best inform screening recommendations, improve understanding of dissection risk, and guide management.     

Matrix metalloproteinase family polymorphisms and the risk of aortic aneurysmal diseases: A systematic review and meta‐analysis

It has been suggested that matrix metalloproteinase (MMP) polymorphisms are associated with the pathogenesis of aortic aneurysmal diseases. In this study, we conducted a systematic review with an update meta‐analysis to investigate the relationship between MMP family polymorphisms and aortic aneurysmal diseases. We systematically reviewed 24 polymorphisms in 8 MMP genes related to the risk of abdominal aortic aneurysm (AAA), thoracic AA or thoracic aortic dissection (TAD). A total of 19 case‐control studies with 15 highly studied MMP polymorphisms were included in our meta‐analysis. Our results suggested that MMP2rs243865, MMP3rs3025058, MMP13rs2252070 polymorphisms were significantly associated with AAA risk, MMP2rs11643630, MMP8rs11225395 polymorphisms were correlated with TAD risk, and MMP9rs3918242 under the dominant model could increase AAA risk in hospital‐based subgroup. No associations with aortic aneurysmal diseases were identified for other polymorphisms assessed in our meta‐analysis. In summary, some studied MMP polymorphisms associated with the risk of aortic aneurysmal diseases are potential predictive biomarkers for the clinical application. Moreover, other MMP polymorphisms with limited studies but relevant to aortic aneurysmal formation and progression need further prospective and large investigations to confirm results.     

Digital vascular lesions detected by transillumination

Abnormalities of the capillaries of the digits in hereditary hemorrhagic telangiectasia can be detected by shining through a narrow beam of light through the dorsal side and visualizing the vasculature on the palmar side, a procedure termed transillumination. This study was performed to determine if this method can detect digital vascular abnormalities in aortopathies and arteriopathies. Transillumination was performed in patients with Marfan syndrome (MFS), thoracic aortic aneurysm and dissection (TAAD), vascular Ehlers–Danlos syndrome (vEDS), bicuspid aortic valve with aortopathy, and arteriopathies without aortopathy. Subjects with no known vascular disorders were controls. Digital vascular abnormalities were present in some patients with all of the disorders and were especially frequent in MFS, TAAD, and vEDS. All patients had significantly more digital vascular abnormalities than control subjects. Transillumination can detect vascular abnormalities in digits of patients with a variety of conditions with aortopathy or arteriopathy.     

A novel SMAD3 mutation caused multiple aneurysms in a patient without osteoarthritis symptoms

Heterozygous mutations in the SMAD3 gene were recently described as the cause of a form of non-syndromic familial aortic thoracic aneurysm and dissection (FTAAD) transmitted as an autosomal dominant disorder and often associated with early-onset osteoarthritis. This new clinical entity, called aneurysms-osteoarthritis syndrome (AOS) or Loeys-Dietz syndrome 3 (LDS3), is characterized by aggressive arterial damages such as aneurysms, dissections and tortuosity throughout the arterial tree. We report, here, the case of a 45 year-old man presenting multiple visceral arteries and abdominal aortic aneurysms but without dissection of the thoracic aorta and without any sign of osteoarthritis. Exome-sequencing revealed a new frameshift heterozygous c.455delC (p.Pro152Hisfs*34) mutation in the SMAD3 gene. This deletion is located in the exon 3 coding for the linker region of the protein and causes a premature stop codon at positions 556–558 in the exon 4. The same mutation was found in the proband's mother and sister who had open surgery for abdominal aortic aneurysm and in one of his children who was 5 year-old and did not present aneurysm yet.     

An unanticipated copy number variant of chromosome 15 disrupting SMAD3 reveals a three‐generation family at serious risk for aortic dissection

Several genes involved in the familial appearance of thoracic aortic aneurysms and dissections (FTAAD) have been characterized recently, one of which is SMAD3. Mutations of SMAD3 cause a new syndromic form of aortic aneurysms and dissections associated with skeletal abnormalities. We discovered a small interstitial deletion of chromosome 15, leading to disruption of SMAD3, in a boy with mild mental retardation, behavioral problems and revealed features of the aneurysms‐osteoarthritis syndrome (AOS). Several family members carried the same deletion and showed features including aortic aneurysms and a dissection. This finding demonstrates that haploinsufficiency of SMAD3 leads to development of both thoracic aortic aneurysms and dissections, and the skeletal abnormalities that form part of the aneurysms‐osteoarthritis syndrome. Interestingly, the identification of this familial deletion is an example of an unanticipated result of a genomic microarray and led to the discovery of important but unrelated serious aortic disease in the proband and family members.     

Inflammatory thoracic aortic aneurysm (lymphoplasmacytic thoracic aortitis): a 13-year-experience at a German Heart Center with emphasis on possible role of IgG4

Background & aim: Aortic aneurysms represent one of the major causes of cardiovascular surgery. Their etiology varies greatly based on patient’s age and other clinicopathologic determinants. In addition to common atherosclerotic vascular diseases, an inflammatory etiology, in particular IgG4-related disease (IgG4-RD) has increasingly emerged as a cause of dissecting inflammatory aortic aneurysms (IAA). Methods: To assess the frequency and types of IAA, we reviewed all cases of aortic aneurysms resected at our Erlangen Heart Center during 2000-2013. Results: 376 patients underwent resection of aortic aneurysms in the study period. These are further categorized as ascending aortic aneurysms (45%), aortic arch aneurysm (2%), descending aortic aneurysm (3%), type A dissection (46%) and type B dissection (4%). Fifteen cases (4%) showed variable lymphoplasmacytic inflammation thus qualifying as IAA. Affected were 9 females and 6 males (female to male ratio = 1.5:1; age range: 52-80 yrs; mean: 70 yrs; median: 72 yrs). None was known to have IgG4-RD and serum IgG4 and/or IgG levels (known in 6 cases) were normal. Variable sclerosing lymphoplasmacytic inflammation was seen either confined to the adventitia (periaortitis; mainly in males) or extending through all layers (mainly in females). A wide range of IgG4 plasma cells (range: 3-182/HPF; mean: 51/HPF) and IgG4: IgG ratios (range: 0.02 to 0.91; mean: 0.37) were detected. All but one of the cases with at least focally transmural inflammation showed a higher IgG4: IgG ratios in excess of 0.3 (range, 0.32-0.91; median, 0.62). Lymphoid follicle and variable fibrosis were common but obliterative phlebitis was not seen. Conclusion: IgG4-rich sclerosing lymphoplasmacytic thoracic aortitis is a constant histological feature of thoracic IAA. Normal serum IgG4 in most patients, predilection for women and absence of other features of IgG4-RD all suggest a tissue-specific localized autoimmunological process and argue against a systemic disorder. The relationship (if any) of IgG4-rich lymphoplasmacytic thoracic aortitis in those patients with IAA lacking other organ manifestations or an elevated serum IgG4 level to systemic IgG4-RD remains unclear and merit further studies.     

An autopsy case of aortic dissection due to giant cell arteritis

Giant cell arteritis (GCA) is a systemic vasculitis affecting mainly large and medium-sized arteries. GCA sometimes involves the aorta and its major branches and causes aortic dissection as a rare complication. We have experienced an autopsy case of aortic dissection due to GCA. The patient was an 87-year-old Japanese woman with Stanford type A aortic dissection who died 7 days after admission. Two years previously she had been diagnosed as having abdominal aortic aneurysm and undergone endovascular aneurysm repair (EVAR). Although she had no characteristic symptoms of GCA, autopsy revealed marked granulomatous inflammation in the dissected area and coronary arteries. Active arteritis was evident not only in the arteries of the upper extremity but also those in the lower extremity. Granulomatous inflammation was not evident in the aneurysm. The aortic dissection might have been an initial manifestation of GCA. We report the regions of GCA extension and its histology in detail.     

Performant Mutation Identification Using Targeted Next‐Generation Sequencing of 14 Thoracic Aortic Aneurysm Genes

At least 14 causative genes have been identified for both syndromic and nonsyndromic forms of thoracic aortic aneurysm/dissection (TAA), an important cause of death in the industrialized world. Molecular confirmation of the diagnosis is increasingly important for gene‐tailored patient management but consecutive, conventional molecular TAA gene screening is expensive and labor‐intensive. To circumvent these problems, we developed a TAA gene panel for next‐generation sequencing of 14 TAA genes. After validation, we applied the assay to 100 Marfan patients. We identified 90 FBN1 mutations, 44 of which were novel. In addition, Multiplex ligation‐dependent probe amplification identified large deletions in six of the remaining samples, whereas false‐negative results were excluded by Sanger sequencing of FBN1, TGFBR1, and TGFBR2 in the last four samples. Subsequently, we screened 55 syndromic and nonsyndromic TAA patients. We identified causal mutations in 15 patients (27%), one in each of the six following genes: ACTA2, COL3A1, TGFBR1, MYLK, SMAD3, SLC2A10 (homozygous), two in NOTCH1, and seven in FBN1. We conclude that our approach for TAA genetic testing overcomes the intrinsic hurdles of consecutive Sanger sequencing of all candidate genes and provides a powerful tool for the elaboration of clinical phenotypes assigned to different genes.     

腔内隔绝术在主动脉瘤外科治疗中的应用

目的：探讨腔内隔绝术治疗主动脉夹层动脉瘤、腹主动脉瘤的操作方法及近期疗效。方法：采用腔内隔绝术治疗主动脉夹层动脉瘤3例、腹主动脉瘤2例。结果：5例主动脉瘤腔内隔绝术均获得成功，术后3例主动脉夹层动脉瘤的假腔立刻消失，2例腹主动脉瘤瘤体成功隔绝。无支架移位；术中发生内漏1例，经及时处理后消失；2例术后出现移植后综合征，经对症处理后缓解。随访3-21个月，无移植物移位及器官缺血，假腔内见血栓形成。结论：腔内隔绝术治疗主动脉瘤创伤小．安全、恢复快，有着较好的近期效果。     

Allometric considerations when assessing aortic aneurysms in Turner syndrome: Implications for activity recommendations and medical decision‐making

In Turner syndrome, the potential to form thoracic aortic aneurysms requires routine patient monitoring. However, the short stature that typically occurs complicates the assessment of severity and risk because the relationship of body size to aortic dimensions is different in Turner syndrome compared to the general population. Three allometric formula have been proposed to adjust aortic dimensions, all employing body surface area: aortic size index, Turner syndrome‐specific Z‐scores, and Z‐scores based on a general pediatric and young adult population. In order to understand the differences between these formula we evaluated the relationship between age and aortic size index and compared Turner syndrome‐specific Z‐scores and pediatric/young adult based Z‐scores in a group of girls and women with Turner syndrome. Our results suggest that the aortic size index is highly age‐dependent for those under 15 years; and that Turner‐specific Z‐scores are significantly lower than Z‐scores referenced to the general population. Higher Z‐scores derived from the general reference population could result in stigmatization, inappropriate restriction from sports, and increasing the risk of unneeded medical or operative treatments. We propose that when estimating aortic dissection risk clinicians use Turner syndrome‐specific Z‐score for those under fifteen years of age.

     

JNK/c-Jun信号通路在大鼠胸主动脉瘤模型中的表达及意义

目的 探讨c -Jun氨基末端激酶(JNK)及c-Jun在实验性大鼠胸主动脉瘤中的表达及其意义. 方法 将20只成年雄性Wistar大鼠随机分为两组,即对照组和手术组.采用氯化钙(CaCl2)诱导法制备胸主动脉瘤模型,于术后4周取外敷CaCl2段胸主动脉.用免疫组织化学和Western blotting方法检测动脉瘤壁JNK和c-Jun的表达. 结果 免疫组织化学显示,磷酸化JNK(p-JNK)和磷酸化c-Jun( p-c-Jun)主要表达于动脉瘤中膜,而对照组表达很弱.Western blotting显示,动脉瘤组织中p-JNK和p-c-Jun表达均强于对照组. 结论 p-JNK和p-c-Jun在动脉瘤中表达强于对照组,JNK/c-Jun信号通路可能在动脉瘤形成过程中起重要作用.     

Autosomal dominant inheritance of a predisposition to thoracic aortic aneurysms and dissections and intracranial saccular aneurysms

A genetic predisposition for thoracic aortic aneurysms and dissections (TAAD) can be inherited in an autosomal dominant manner with decreased penetrance and variable expression. Four genes identified to date for familial TAAD account for approximately 20% of the heritable predisposition. In a cohort of 514 families with two or more members with presumed autosomal dominant TAAD, 48 (9.3%) families have one or more members who were at 50% risk to inherit the presumptive gene causing TAAD had an intracranial vascular event. In these families, gender is significantly associated with disease presentation (P < 0.001), with intracranial events being more common in women (65.4%) while TAAD events occurred more in men (64.2%,). Twenty‐nine of these families had intracranial aneurysms (ICA) that could not be designated as saccular or fusiform due to incomplete data. TGFBR1, TGFBR2, and ACTA2 mutations were found in 4 families with TAAD and predominantly fusiform ICAs. In 15 families, of which 14 tested negative for 3 known TAAD genes, 17 family members who were at risk for inheriting TAAD had saccular ICAs. In 2 families, women who harbored the genetic mutation causing TAAD had ICAs. In 2 additional families, intracranial, thoracic and abdominal aortic aneurysms were observed. This study documents the autosomal dominant inheritance of TAADs with saccular ICAs, a previously recognized association that has not been adequately characterized as heritable. In these families, routine cerebral and aortic imaging for at risk members could prevent cerebral hemorrhages and aortic dissections. © 2011 Wiley‐Liss, Inc.     

高脂饮食对大鼠胸主动脉瘤形成过程中细胞黏附分子表达的影响

目的 探讨高脂饮食对胸主动脉瘤形成过程中细胞黏附分子包括血管细胞黏附分子-1(VCAM-1)和细胞间黏附分子-1(ICAM-1)表达的影响.方法 将30只成年雄性Wistar大鼠随机分为3组,即对照组、手术组和高脂饮食组,采用氯化钙(CaCl2)诱导法制备胸主动脉瘤模型,于术后4周取外敷CaCl2段胸主动脉.采用地衣红染色和HE染色观察胸主动脉形态学改变;免疫组织化学技术检测CD45、VCAM-1和ICAM-1的表达.结果 高脂饮食组动脉管径较手术组扩张明显,动脉管壁破坏更广泛,伴有更多的炎性细胞浸润;VCAM-1、ICAM-1较手术组表达升高.结论 高脂饮食可促进胸主动脉瘤管壁VCAM-1和ICAM-1的表达.     

Aortic arch geometry predicts outcome in patients with Loeys–Dietz syndrome independent of the causative gene

This study aimed to investigate the potential association between imaging features and cardiovascular outcomes in patients with Loeys–Dietz syndrome (LDS). We performed a retrospective cohort study of 36 patients with LDS and described cardiovascular events and imaging data. We observed different clinical courses in patients with LDS, irrespective of the causative gene. Angular or elongated aortic arch geometry correlated with aortic dissection (R = .39, p = .02), occurrence of the first cardiovascular event before 45 years of age (R = .36, p = .03), and the number of operations (R = 0.47, p = .004), but not with age (R = ?.05, p = .79) or the causative gene (R = ?0.04, p = .79). Relative absences of cardiovascular events at ages 20, 40, and 60 were 100, 75, and 56%, respectively, in patients with “romanesque” aortic arches, and 74, 39, and 21%, respectively, in patients with “gothic” and “elongated” aortic arches (p = .03). Angular or elongated aortic arch geometry is associated with early‐onset of disease and a worse cardiovascular outcome in LDS patients. Large multicenter studies are warranted to elucidate the impact of aortic arch morphology evaluation in clinical practice.     

Expanding the genetic and phenotypic spectrum of ACTA2-related vasculopathies in a Dutch cohort

PurposeHeterozygous pathogenic/likely pathogenic (P/LP) variants in the ACTA2 gene confer a high risk for thoracic aortic aneurysms and aortic dissections. This retrospective multicenter study elucidates the clinical outcome of ACTA2-related vasculopathies.MethodsIndex patients and relatives with a P/LP variant in ACTA2 were included. Data were collected through retrospective review of medical records using a standardized questionnaire.ResultsA total of 49 individuals from 28 families participated in our study. In total, 20 different ACTA2 variants were detected. Aortic events occurred in 65% of the cases (78.6% index patients and 47.6% relatives). Male sex and hypertension emerged as significantly associated with aortic events. Of 20 individuals, 5 had an aortic diameter of <45 mm (1.77 inches) at the time of the type A dissection. Mean age at first aortic event was 49.0 ± 12.4 years. Severe surgical complications for type A and type B dissection occurred in 25% and 16.7% of the cases and in-hospital mortality rates were 9.5% and 0%, respectively.ConclusionP/LP ACTA2 variants are associated with an increased risk for an aortic event and age-related penetrance, which emphasizes the importance of early recognition of the disease. Caregivers should be aware of the risk for aortic dissections, even in individuals with aortic diameters within the normal range.     

姜黄素对大鼠胸主动脉瘤Bcl-2和Bax表达的影响

目的 探讨姜黄素对大鼠胸主动脉瘤形成过程中Bcl-2和Bax表达的影响。方法 将30只成年雄性Wistar大鼠随机分为3组,即对照组、动脉瘤组和姜黄素治疗组。采用氯化钙（CaCl2）诱导法制备胸主动脉瘤模型,术后4周取材。HE染色及地衣红染色观察胸主动脉组织学改变;免疫组织化学和Western blotting方法检测动脉瘤壁Bcl-2和Bax的表达。结果 姜黄素可明显抑制胸主动脉的扩张。与对照组比较,动脉瘤组Bax表达水平明显升高,Bcl-2表达水平降低,姜黄素能有效降低动脉瘤中Bax的表达,升高Bcl-2表达水平。 结论 姜黄素可以促进胸主动脉瘤Bc1-2蛋白的表达,抑制Bax蛋白的表达,降低Bax/Bcl-2的比值。