Genetics of syndromic and nonsyndromic aortopathies.

PURPOSE OF REVIEW: To review the literature and provide a summary of management of syndromic and nonsyndromic aortopathies. RECENT FINDINGS: The number of newly identified genetic causes for aortopathies have continued to increase over the past 10 years. The number of reported individuals with most hereditary aneurysm genes is small but increasing with more publications focusing describing the natural history caused by each gene. SUMMARY: Aortopathy can present as an isolated finding or present as part of a larger genetic syndrome. Advances in genetic testing technology has shed light on the increasing importance of molecular diagnostics in the evaluation and management of patients with hereditary aortic disease. Molecular diagnostics and family phenotyping can aide in the diagnosis and management of pediatric patients with aortic disease.

Loeys-Dietz syndrome: Intermediate-term outcomes of medically and surgically managed patients.

OBJECTIVES: Loeys-Dietz syndrome (LDS) is an aggressive connective tissue disorder associated with increased risk of aortic dissection and aneurysm rupture at an early age and smaller aortic diameters. We report our experience with LDS to better understand its natural history and treatment outcomes and help establish treatment guidelines. METHODS: We retrospectively reviewed all patients with LDS who underwent medical or surgical treatment at Cleveland Clinic before April 27, 2017. Primary endpoints were postoperative in-hospital morbidity and mortality. Secondary endpoints were aorta-related reoperations and short- and long-term mortality. RESULTS: We identified 53 patients with LDS. Of these, 33 (62%) underwent aortic surgery. Mean age was 39 ± 14 years, and mean maximum aortic diameter was 4.3 cm. There were 2 (6%) deaths after urgent or emergency surgery. Twenty-two patients (67%) required no aortic reoperation; 20 of these had prophylactic surgery. Multiple aortic operations were performed on 11 (33%) patients, 9 of whom experienced aortic dissections. Six patients (18%) required total aortic replacement. Among 19 patients with modified root reimplantation, no aorta- or valve-related complications occurred. Overall, 33 patients underwent 58 aortic and 81 cardiovascular operations, with 1 late death. Kaplan-Meier survival of the aortic-surgery cohort was 89% at 10 years (median follow-up 5.2 years). There were no late deaths in the non-aortic surgery group (20/53; 38%). CONCLUSIONS: Prophylactic aortic surgical outcomes in LDS are excellent. Surgical reintervention remains high, particularly after aortic dissections. Close surveillance of medically managed and postoperative patients and early prophylactic surgery are crucial to avoid aortic catastrophe and achieve a good long-term prognosis.

Increased Mutagen Sensitivity and DNA Damage in Pulmonary Arterial Hypertension.

RATIONALE: Pulmonary arterial hypertension (PAH) is a serious lung condition characterized by vascular remodeling in the precapillary pulmonary arterioles. We and others have demonstrated chromosomal abnormalities and increased DNA damage in PAH lung vascular cells, but their timing and role in disease pathogenesis is unknown. OBJECTIVES: We hypothesized that if DNA damage predates PAH, it might be an intrinsic cell property that is present outside the diseased lung. METHODS: We measured DNA damage, mutagen sensitivity, and reactive oxygen species (ROS) in lung and blood cells from patients with Group 1 PAH, their relatives, and unrelated control subjects. MEASUREMENTS AND MAIN RESULTS: Baseline DNA damage was significantly elevated in PAH, both in pulmonary artery endothelial cells (P < 0.05) and peripheral blood mononuclear cells (PBMC) (P < 0.001). Remarkably, PBMC from unaffected relatives showed similar increases, indicating this is not related to PAH treatments. ROS levels were also higher (P < 0.01). DNA damage correlated with ROS production and was suppressed by antioxidants (P < 0.001). PBMC from patients and relatives also showed markedly increased sensitivity to two chemotherapeutic drugs, bleomycin and etoposide (P < 0.001). Results were consistent across idiopathic, heritable, and associated PAH groups. CONCLUSIONS: Levels of baseline and mutagen-induced DNA damage are intrinsically higher in PAH cells. Similar results in PBMC from unaffected relatives suggest this may be a genetically determined trait that predates disease onset and may act as a risk factor contributing to lung vascular remodeling following endothelial cell injury. Further studies are required to fully characterize mutagen sensitivity, which could have important implications for clinical management.

Family history of aortic disease predicts disease patterns and progression and is a significant influence on management strategies for patients and their relatives.

BACKGROUND: While a positive family history (FH) is a known risk factor for developing an aneurysm, its association with the extent of disease has not been established. We evaluated the influence of a FH of aortic disease with respect to the pattern and distribution of aortic aneurysms in a given patient. METHODS AND RESULTS: From November 1999 to November 2011, 1263 patients were enrolled in physician-sponsored endovascular device trials to treat aortic aneurysms. Of the 555 patients who were alive and returning for follow-up, we obtained 426 (77%) family histories. Three-dimensional imaging studies were used to identify the presence of aneurysms; 36% (155/426) of patients had a FH of aortic aneurysms and 5% (21/155) had isolated intracranial aneurysms. A logistic regression model was used to compare aortic morphology between patients with a positive or negative FH for aneurysms. Patients with a positive FH of aortic aneurysms were younger at their initial aneurysm (63 vs 70 years; P < .0001), more frequently had proximal aortic involvement (root: odds ratio [OR], 5.4; P < .0001; ascending: OR, 2.9; P < .001; thoracic: OR, 2.2; P = .01) with over 50% of FH patients ultimately developing suprarenal aortic involvement (P = .0001) and had a greater incidence of bilateral iliac artery aneurysm (OR, 1.8; P = .03). CONCLUSIONS: FH is an important tool that provides insight into the expected behavior of the untreated aorta and has significant implications for the development of treatment strategies. These findings should be used to guide patient's management with regard to treatment, follow-up paradigms, genetic testing, and screening of other family members.

Low yield of genetic testing for known vascular connective tissue disorders in patients with fibromuscular dysplasia.

Patients with fibromuscular dysplasia (FMD) may have clinical features consistent with Mendelian vascular connective tissue disorders. The yield of genetic testing for these disorders among patients with FMD has not been determined. A total of 216 consecutive patients with FMD were identified. Clinical characteristics were collected and genetic test results reviewed for abnormalities in the following genes: transforming growth factor-ß receptor 1 and 2 (TGFßR1 and TGFßR2), collagen 3A1, fibrillin-1, smooth muscle α-actin 2, and SMAD3. A total of 63 patients (63/216; 29.2%) were referred for genetic counseling with testing performed in 35 (35/63; 55.6%). The percentage of patients with a history of arterial or aortic dissection, history of aortic aneurysm, systemic features of a connective tissue disorder, and a family history of sudden death was significantly larger in the group that underwent genetic testing (62.9% vs 18.2%, p < 0.001; 8.6% vs 1.7%, p = 0.02; 51.4% vs 17.1%, p < 0.001; and 42.9% vs 22.7%, p = 0.04, respectively). Two patients were found to have distinct variants in the TGFßR1 gene (c.611 C>T, p.Thr204lle and c.1285 T>C, p.Tyr429His). The yield of genetic testing for vascular connective tissue disorders was low in a high-risk subset of FMD patients. However, two patients with a similar phenotype had novel and distinct variants in the TGFßR1 gene, a finding which merits further investigation.

BMPR2 mutation in a patient with pulmonary arterial hypertension and suspected hereditary hemorrhagic telangiectasia.

Pulmonary arterial hypertension (PAH) and hereditary hemorrhagic telangiectasia (HHT) are distinct clinical entities caused by germline mutations in genes encoding members of the TGFbeta/BMP superfamily: BMPR2 in PAH and ACVRL1, ENG, or SMAD4 in HHT. When PAH and HHT occasionally co-exist within the same family, ACVRL1 mutations predominate. We report a 36-year-old woman initially diagnosed with PAH at age 24. At 35, following massive hemoptysis, multiple pulmonary arteriovenous malformations were discovered, prompting evaluation for HHT. She met the Curaçao diagnostic criteria for suspected HHT based on additional findings of nasal telangiectases and epistaxis. Mutation analysis of ACVRL1, ENG, and SMAD4 was normal, but a germline nonsense mutation in BMPR2 was identified. This is the first known report of HHT features, particularly pulmonary AVMs, associated with a BMPR2 mutation. It adds further weight to a common molecular pathogenesis in PAH and HHT, and highlights that BMPR2 gene analysis is indicated in patients affected with both HHT and PAH.