Increased aortic tortuosity indicates a more severe aortic phenotype in adults with Marfan syndrome

Progression of arterial toursosity syndrome to multiple aneurysms: Role of defining aortic flow and biomechanics

Arterial tortuosity syndrome (ATS) is a rare aortopathy characterized by multiple areas of tortuosity, stenosis and aneurysms in large and mid-sized arteries. The management of this syndrome is challenging because its complexity and variability in presentation and progression require a thorough understanding of the biological and biomechanical changes that occur in the arterial system. Here we describe, for the first time, the progression of this disease diagnosed in a 3-year old girl and the use of modern imaging modalities including cardiac magnetic resonance (CMR) 4D Flow, 3D modeling, and computational fluid dynamic simulation to characterize the complex aortic flow and its biomechanics. The integration of these modalities with the clinical evaluation will help in our understanding of this disease and provide patient-specific management.

Comparability of semiautomatic tortuosity measurements in the carotid artery

Purpose

Increased arterial tortuosity has been suggested as a predisposing factor for carotid artery dissection, which is an important risk factor for development of extracranial carotid artery aneurysms (ECAA). Prior to comparison with non-ECAA controls, the optimal measurement technique should be defined. This study describes the difference between software packages in terms of reproducibility and absolute outcome of arterial tortuosity measurements in ECAA patients.

Methods

CT-angiography analysis was performed on 12 ECAA patients selected from our registry, using four software packages: 3mensio Vascular, TeraRecon, Vital Images, and Aycan OsiriX PRO. The tortuosity index (TI) was calculated from the skull base until the carotid bifurcation and aortic arch, and was defined as the centerline’s true length divided by the straight line distance. Intraclass correlation coefficients (ICC) with 95% confidence intervals were calculated to quantify inter- and intra-observer variability within one software package, and differences in measured TI between packages.

Results

Inter-observer agreement was nearly perfect for 3mensio, excellent for Vital Images and OsiriX, and substantial for TeraRecon, with ICC 0.99 (0.96–1.0), 0.90 (0.69–0.97), 0.84 (0.53–0.95), and 0.72 (0.28–0.91), respectively. Intra-observer agreement ranged from ICC 1.0 for 3mensio to 0.91 for TeraRecon. Agreements in TI ranged from ICC 0.99 (0.98–1.0) for 3mensio vs. OsiriX, to 0.95 (0.82–0.98) for 3mensio vs. TeraRecon. Median time needed to complete one round of measurements was highest for OsiriX (p = 0.013).

Conclusions

Carotid artery tortuosity measurements are reproducible and comparable between current commercially available software packages, with high intra-observer agreement. Although the reproducibility differed per software packages, all packages scored an acceptable inter-observer agreement.

Aortic arch tortuosity, a novel biomarker for thoracic aortic disease, is increased in adults with bicuspid aortic valve

INTRODUCTION

Arterial tortuosity has emerged as a predictor of adverse outcomes in congenital aortopathies using 3D reconstructed images. We validated a new method to estimate aortic arch tortuosity on 2D CT. We hypothesize that arch tortuosity may identify bicuspid aortic valve (BAV) patients at high risk to develop thoracic aortic aneurysms or aortic dissections (TAD).

METHODS

BAV subjects with chest CT scans were retrospectively identified in our clinical records and matched to tricuspid aortic valve (TAV) controls by age, gender, and presentation with TAD. Subjects with prior ascending aortic intervention were excluded. Measurements included aortic arch tortuosity, length, angle, width and height. Total aortic tortuosity was estimated in subjects with available abdominal images.

RESULTS

120 BAV and 234 TAV subjects were included. Our 2D measurements were highly correlated with 3D midline arch measurements and had high inter- and intra-observer reliability. Compared to TAV, BAV subjects had increased arch tortuosity (median 1.76 [Q1-Q3: 1.62-1.95] vs. 1.63 [1.53-1.78], P < 0.01), length (149 [136-160] vs. 135 [122-152] mm, P < 0.01), height (46 [41-53] vs. 39 [34-47] mm, P < 0.01), and vertex acuity (70 [61-77] vs. 75 [68-81] degree, P < 0.01). In a multivariable analysis, arch tortuosity remained independently associated with BAV after adjusting for aortic diameter and other clinical characteristics.

CONCLUSIONS

We found that aortic arch tortuosity is significantly increased in BAV and may identify BAV patients who are at increased risk for TAD. Further studies to evaluate the association between tortuosity and clinical outcomes are in progress.

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.

Lung Transplantation for FLNA-Associated Progressive Lung Disease

OBJECTIVE

To describe a series of patients with pathogenic variants in FLNA and progressive lung disease necessitating lung transplantation.

STUDY DESIGN

We conducted a retrospective chart review of 6 female infants with heterozygous presumed loss-of-function pathogenic variants in FLNA whose initial presentation was early and progressive respiratory failure.

RESULTS

Each patient received lung transplantation at an average age of 11 months (range, 5-15 months). All patients had pulmonary arterial hypertension and chronic respiratory failure requiring tracheostomy and escalating levels of ventilator support before transplantation. All 6 patients survived initial lung transplantation; however, 1 patient died after a subsequent heart-lung transplant. The remaining 5 patients are living unrestricted lives on chronic immunosuppression at most recent follow-up (range, 19 months to 11.3 years post-transplantation). However, in all patients, severe ascending aortic dilation has been observed with aortic regurgitation.

CONCLUSIONS

Respiratory failure secondary to progressive obstructive lung disease during infancy may be the presenting phenotype of FLNA-associated periventricular nodular heterotopia. We describe a cohort of patients with progressive respiratory failure related to a pathogenic variant in FLNA and present lung transplantation as a viable therapeutic option for this group of patients.

International Registry of Patients Carrying TGFBR1 or TGFBR2 Mutations: Results of the MAC (Montalcino Aortic Consortium)

BACKGROUND

The natural history of aortic diseases in patients with TGFBR1 or TGFBR2 mutations reported by different investigators has varied greatly. In particular, the current recommendations for the timing of surgical repair of the aortic root aneurysms may be overly aggressive.

METHODS AND RESULTS

The Montalcino Aortic Consortium, which includes 15 centers worldwide that specialize in heritable thoracic aortic diseases, was used to gather data on 441 patients from 228 families, with 176 cases harboring a mutation in TGBR1 and 265 in TGFBR2. Patients harboring a TGFBR1 mutation have similar survival rates (80% survival at 60 years), aortic risk (23% aortic dissection and 18% preventive aortic surgery), and prevalence of extra-aortic features (29% hypertelorism, 53% cervical arterial tortuosity, and 27% wide scars) when compared with patients harboring a TGFBR2 mutation. However, TGFBR1 males had a greater aortic risk than females, whereas TGFBR2 males and females had a similar aortic risk. Additionally, aortic root diameter prior to or at the time of type A aortic dissection tended to be smaller in patients carrying a TGFBR2 mutation and was ≤45 mm in 6 women with TGFBR2 mutations, presenting with marked systemic features and low body surface area. Aortic dissection was observed in 1.6% of pregnancies.

CONCLUSIONS

Patients with TGFBR1 or TGFBR2 mutations show the same prevalence of systemic features and the same global survival. Preventive aortic surgery at a diameter of 45 mm, lowered toward 40 in females with low body surface area, TGFBR2 mutation, and severe extra-aortic features may be considered.

The role of the multidisciplinary health care team in the management of patients with Marfan syndrome

Marfan syndrome (MFS) is a rare, severe, chronic, life-threatening disease with multiorgan involvement that requires optimal multidisciplinary care to normalize both prognosis and quality of life. In this article, each key team member of all the medical disciplines of a multidisciplinary health care team at the Hamburg Marfan center gives a personal account of his or her contribution in the management of patients with MFS. The authors show how, with the support of health care managers, key team members organize themselves in an organizational structure to create a common meaning, to maximize therapeutic success for patients with MFS. First, we show how the initiative and collaboration of patient representatives, scientists, and physicians resulted in the foundation of Marfan centers, initially in the US and later in Germany, and how and why such centers evolved over time. Then, we elucidate the three main structural elements; a team of coordinators, core disciplines, and auxiliary disciplines of health care. Moreover, we explain how a multidisciplinary health care team integrates into many other health care structures of a university medical center, including external quality assurance; quality management system; clinical risk management; center for rare diseases; aorta center; health care teams for pregnancy, for neonates, and for rehabilitation; and in structures for patient centeredness. We provide accounts of medical goals and standards for each core discipline, including pediatricians, pediatric cardiologists, cardiologists, human geneticists, heart surgeons, vascular surgeons, vascular interventionists, orthopedic surgeons, ophthalmologists, and nurses; and of auxiliary disciplines including forensic pathologists, radiologists, rhythmologists, pulmonologists, sleep specialists, orthodontists, dentists, neurologists, obstetric surgeons, psychiatrist/psychologist, and rehabilitation specialists. We conclude that a multidisciplinary health care team is a means to maximize therapeutic success.

Function of Ltbp-4L and fibulin-4 in survival and elastogenesis in mice

LTBP-4L and LTBP-4S are two isoforms of the extracellular matrix protein latent-transforming growth factor beta-binding protein 4 (LTBP-4). The mutational inactivation of both isoforms causes autosomal recessive cutis laxa type 1C (ARCL1C) in humans and an ARCL1C-like phenotype in Ltbp4^-/- mice, both characterized by high postnatal mortality and severely affected elastogenesis. However, genetic data in mice suggest isoform-specific functions for Ltbp-4 because Ltbp4S^-/- mice, solely expressing Ltbp-4L, survive to adulthood. This clearly suggests a requirement of Ltbp-4L for postnatal survival. A major difference between Ltbp4S^-/- and Ltbp4^-/- mice is the matrix incorporation of fibulin-4 (a key factor for elastogenesis; encoded by the Efemp2 gene), which is normal in Ltbp4S^-/- mice, whereas it is defective in Ltbp4^-/- mice, suggesting that the presence of Ltbp-4L might be required for this process. To investigate the existence of a functional interaction between Ltbp-4L and fibulin-4, we studied the consequences of fibulin-4 deficiency in mice only expressing Ltbp-4L. Resulting Ltbp4S^-/-;Fibulin-4^R/R mice showed a dramatically reduced lifespan compared to Ltbp4S^-/- or Fibulin-4^R/R mice, which survive to adulthood. This dramatic reduction in survival of Ltbp4S^-/-;Fibulin-4^R/R mice correlates with severely impaired elastogenesis resulting in defective alveolar septation and distal airspace enlargement in lung, and increased aortic wall thickness with severely fragmented elastic lamellae. Additionally, Ltbp4S^-/-;Fibulin-4^R/R mice suffer from aortic aneurysm formation combined with aortic tortuosity, in contrast to Ltbp4S^-/- or Fibulin-4^R/R mice. Together, in accordance with our previous biochemical findings of a physical interaction between Ltbp-4L and fibulin-4, these novel in vivo data clearly establish a functional link between Ltbp-4L and fibulin-4 as a crucial molecular requirement for survival and elastogenesis in mice.

Vascular Tortuosity May Be Associated With Cervical Artery Dissection

BACKGROUND AND PURPOSE

Dissection is an increasingly recognized cause of ischemic stroke, which occurs spontaneously or after trauma, in relatively young patients. We hypothesized that there might be a predisposing factor weakening the vascular wall and that arterial tortuosity might be higher in patients with dissection.

METHODS

We consecutively enrolled cervical artery dissection (CerAD) patients who had undergone magnetic resonance angiography. Age- and sex-matched healthy subjects who underwent magnetic resonance angiography in a routine health examination were used as controls. The tortuosity was measured semiautomatically from the carotid artery and vertebral artery (VA) arteries. Tortuosity index was defined as: [(arc/chord)-1×100] in each arteries. Independent risk factors associated with CerAD were investigated using multivariable analysis. Subgroup analysis according to the dissected artery was performed.

RESULTS

There were no differences in vascular risk factors between the 75 CerAD patients and the 75 controls. The tortuosity indexes of the contralesional VA (16.3±6.8 versus 12.1±4.5, respectively; P<0.001) and carotid artery (8.8±4.0 versus 7.3±2.9, respectively; P=0.01) were higher in patients with CerAD compared with those of control subjects. VA tortuosity (odds ratio, 1.175; P=0.001) was independently associated with the presence of CerAD. In subgroup analysis, VA tortuosity was significantly higher in 57 patients with VA dissection than in controls (P<0.001), and carotid artery tortuosity was marginally higher in 18 patients with carotid artery dissection (P=0.05).

CONCLUSIONS

CerAD is associated with tortuous cervical arteries, which may implicate weakened cervical vascular structure in these patients.

Novel 3D light microscopic analysis of IUGR placentas points to a morphological correlate of compensated ischemic placental disease in humans

The villous tree of the human placenta is a complex three-dimensional (3D) structure with branches and nodes at the feto-maternal border in the key area of gas and nutrient exchange. Recently we introduced a novel, computer-assisted 3D light microscopic method that enables 3D topological analysis of branching patterns of the human placental villous tree. In the present study we applied this novel method to the 3D architecture of peripheral villous trees of placentas from patients with intrauterine growth retardation (IUGR placentas), a severe obstetric syndrome. We found that the mean branching angle of branches in terminal positions of the villous trees was significantly different statistically between IUGR placentas and clinically normal placentas. Furthermore, the mean tortuosity of branches of villous trees in directly preterminal positions was significantly different statistically between IUGR placentas and clinically normal placentas. We show that these differences can be interpreted as consequences of morphological adaptation of villous trees between IUGR placentas and clinically normal placentas, and may have important consequences for the understanding of the morphological correlates of the efficiency of the placental villous tree and their influence on fetal development.

Recent progress in understanding the natural and clinical histories of the Marfan syndrome

Over the past 4 decades, remarkable progress in understanding the cause, pathogenesis, and management of the MFS has led to an increase in life expectancy to near normal for most patients. Accompanying this increased life span has been the emergence of previously rare or unanticipated clinical problems. Despite much more detailed knowledge of the molecular, cellular, and tissue effects of a mutation in FBN1, targeted, effective therapy remains elusive. Until such precision medicine takes hold, management will depend on early diagnosis, regular scrutiny by imaging, chronic β-blockade, and perhaps ARBs, and prophylactic cardiothoracic surgery. Without question, MFS will remain a fertile subject for basic, translational, and clinical research for the foreseeable future.

The Expanding Clinical Spectrum of Extracardiovascular and Cardiovascular Manifestations of Heritable Thoracic Aortic Aneurysm and Dissection

More than 30 heritable conditions are associated with thoracic aortic aneurysm and dissection (TAAD). Heritable syndromic conditions, such as Marfan syndrome, Loeys-Dietz syndrome, and vascular Ehlers-Danlos syndrome, have somewhat overlapping systemic features, but careful clinical assessment usually enables a diagnosis that can be validated with genetic testing. Nonsyndromic FTAAD can also occur and in 20%-25% of these probands mutations exist in genes that encode elements of the extracellular matrix, signalling pathways (especially involving transforming growth factor-β), and vascular smooth muscle cytoskeletal and contractile processes. Affected individuals with either a syndromic presentation or isolated TAAD can have mutations in the same gene. In this review we focus on the genes currently known to have causal mutations for syndromic and isolated FTAAD and outline the range of associated extracardiovascular and cardiovascular manifestations with each.