Correlation of four-dimensional ultrasound strain analysis with computed tomography angiography wall stress simulations in abdominal aortic aneurysms.

Objective: Biomechanical modeling of infrarenal aortic aneurysms seeks to predict ruptures in advance, thereby reducing aneurysm-related deaths. As individual methods focusing on strain and stress analysis lack adequate discretization power, this study aims to explore multifactorial characterization for progressive aneurysmal degeneration. The study's objective is to compare stress- and strain-related parameters in infrarenal aortic aneurysms. Methods: Twenty-two patients with abdominal aortic aneurysms (AAAs) (mean maximum diameter, 53.2 ± 7.2 mm) were included in the exploratory study, examined by computed tomography angiography (CTA) and three-dimensional real-time speckle tracking ultrasound (4D-US). The conformity of aneurysm anatomy in 4D-US and CTA was determined with the mean point-to-point distance (MPPD). CTA was employed for each AAA to characterize stress-related indices using the semi-automated A4-clinics RE software. Five segmentations from one 4D-US examination were fused into one averaged model for strain analysis using MATLAB and the Abaqus solver. Results: The mean MPPD between the adjacent points of the 4D-US and CTA-derived geometry was 1.8 ± 0.4 mm. The interclass correlation coefficients for all raters and all measurements for the maximum AAA diameter in 2D, 4D ultrasound, and CTA indicate moderate to good reliability (interclass correlation coefficient1 0.69 with 95% confidence interval [CI], 0.49-0.84; P < .001). The peak wall stress (PWS) correlates fairly with the maximum AAA diameter in 2D-US (r = 0.54; P < .01) and 4D-US (r = 0.53; P < .05) and moderately strongly with the maximum exterior AAA diameter (r = 0.63; P < .01). The peak wall rupture risk index shows a strong correlation with the PWS (ρ > 0.9; P < .001) and is influenced by anatomical parameters with equal strength. Isolated observation of the intraluminal thrombus does not provide significant information in the determination of PWS. The maximum AAA diameter in 2D-US shows a fair negative correlation with the mean circumferential, longitudinal and in-plane shear strain (ρ = -0.46; r = -0.45; ρ = -0.47; P < .05 for all). The circumferential strain ratio as an indicator of wall motion heterogeneity increases with the aneurysm diameter (r = 0.47; P < .05). The direct comparison of wall strain and wall stress indices shows no quantitative correlation. Conclusions: The strain and stress analyses provide independent biomechanical information of AAAs. At the current stage of development, the two methods are considered complementary and may optimize a more patient-specific rupture risk prediction in the future.

Co-prevalence of arterial aneurysm location - a correlation analysis based on a retrospective cross-sectional observational study.

Background: The aim of this retrospective single-centre cross-sectional observational study was to investigate co-prevalence of arterial aneurysm location systematically. Patients and methods: Patients with the diagnosis of any arterial aneurysm from January 2006 to January 2016 were investigated in a single centre. Patients with hereditary disorders of connective tissue, systemic inflammatory disease, or arterial pathologies other than true aneurysms were excluded. Aneurysm locations were assessed for every patient included. For patients with at least two co-existing aneurysms, co-prevalence of aneurysm location was investigated by calculating correlation coefficients and applying Fisher's exact test. This study report is prepared according to the STROBE statement. Results: Of 3107 identified patients with arterial aneurysms, 918 were excluded. Of the remaining 2189 patients, 951 patients with at least two aneurysms were included in the study. Bilateral aneurysm combinations of paired iliac, femoral and popliteal arteries showed the highest correlation (ϕ=0.35 to 0.67), followed by bilateral combinations of subclavian (ϕ=0.36) and internal carotid (ϕ=0.38) arteries. Abdominal aortic aneurysms in combination with visceral artery aneurysms (ϕ=-0.24 to -0.12), popliteal arteries (ϕ=-0.22) and the ascending aorta (ϕ=-0.19) showed the lowest correlation, followed by the descending aorta in combination with the common iliac arteries (ϕ=-0.12 to -0.13). Conclusions: In our study sample, aneurysm co-prevalence was highly non-random. This should be considered in the context of aneurysm screening programs.

A novel scatterplot-based method to detect copy number variation (CNV).

Objective: Most methods to detect copy number variation (CNV) have high false positive rates, especially for small CNVs and in real-life samples from clinical studies. In this study, we explored a novel scatterplot-based method to detect CNVs in microarray samples. Methods: Illumina SNP microarray data from 13,254 individuals were analyzed with scatterplots and by PennCNV. The data were analyzed without the prior exclusion of low-quality samples. For CNV scatterplot visualization, the median signal intensity of all SNPs located within a CNV region was plotted against the median signal intensity of the flanking genomic region. Since CNV causes loss or gain of signal intensities, carriers of different CNV alleles pop up in clusters. Moreover, SNPs within a deletion are not heterozygous, whereas heterozygous SNPs within a duplication show typical 1:2 signal distribution between the alleles. Scatterplot-based CNV calls were compared with standard results of PennCNV analysis. All discordant calls as well as a random selection of 100 concordant calls were individually analyzed by visual inspection after noise-reduction. Results: An algorithm for the automated scatterplot visualization of CNVs was developed and used to analyze six known CNV regions. Use of scatterplots and PennCNV yielded 1019 concordant and 108 discordant CNV calls. All concordant calls were evaluated as true CNV-findings. Among the 108 discordant calls, 7 were false positive findings by the scatterplot method, 80 were PennCNV false positives, and 21 were true CNVs detected by the scatterplot method, but missed by PennCNV (i.e., false negative findings). Conclusion: CNV visualization by scatterplots allows for a reliable and rapid detection of CNVs in large studies. This novel method may thus be used both to confirm the results of genome-wide CNV detection software and to identify known CNVs in hitherto untyped samples.

Histopathological Characterization of Abdominal Aortic Aneurysms from Patients with Multiple Aneurysms Compared to Patients with a Single Abdominal Aortic Aneurysm.

The aim of this study was to investigate histopathological differences in abdominal aortic aneurysms (AAAs) between patients with multiple and single arterial aneurysms, as we suspect that there are different underlying mechanisms in aneurysm formation. Analysis was based on a previous retrospective study on patients with multiple arterial aneurysms (mult-AA; defined as at least four, n = 143) and a single AAA (sing-AAA, n = 972) who were admitted to our hospital for treatment between 2006 and 2016. Available paraffin-embedded AAA wall specimens were derived from the Vascular Biomaterial Bank Heidelberg (mult-AA, n = 12 vs. sing-AAA, n = 19). Sections were analyzed regarding structural damage of the fibrous connective tissue and inflammatory cell infiltration. Alterations to the collagen and elastin constitution were assessed by Masson-Goldner trichrome and Elastica van Gieson staining. Inflammatory cell infiltration, response and transformation were assessed by CD45 and IL-1ß immunohistochemistry and von Kossa staining. The extent of aneurysmal wall alterations was assessed by semiquantitative gradings and was compared between the groups using Fisher's exact test. IL-1ß was significantly more present in the tunica media in mult-AA compared to sing-AAA (p = 0.022). The increased expression of IL-1ß in mult-AA compared to sing-AAA indicates inflammatory processes play a role in aneurysm formation in patients with multiple arterial aneurysms.

Association of Tumor Volumetry with Postoperative Outcomes for Cervical Paraganglioma.

Objectives: To analyze the association of tumor volume with outcome after surgery for cervical paraganglioma. Materials and Methods: This retrospective study included consecutive patients undergoing surgery for cervical paraganglioma from 2009-2020. Outcomes were 30-day morbidity, mortality, cranial nerve injury, and stroke. Preoperative CT/MRI was used for tumor volumetry. An association between the volume and the outcomes was explored in univariate and multivariable analyses. A receiver operating characteristic (ROC) curve was plotted, and the area under the curve (AUC) was calculated. The study was conducted and reported according to the STROBE statement. Results: Volumetry was successful in 37/47 (78.8%) of included patients. A 30-day morbidity occurred in 13/47 (27.6%) patients with no mortality. Fifteen cranial nerve lesions occurred in eleven patients. The mean tumor volume was 6.92 cm3 in patients without and 15.89 cm3 in patients with complications (p = 0.035) and 7.64 cm3 in patients without and 16.28 cm3 in patients with cranial nerve injury (p = 0.05). Neither the volume nor Shamblin grade was significantly associated with complications on multivariable analysis. The AUC was 0.691, indicating a poor to fair performance of volumetry in predicting postoperative complications. Conclusions: Surgery for cervical paraganglioma bears a relevant morbidity with a particular risk of cranial nerve lesions. Tumor volume is associated with morbidity, and MRI/CT volumetry can be used for risk stratification.

Case report: Resuscitative endovascular balloon occlusion after iatrogenic injury of the common iliac artery during neurosurgical dorsal lumbar microdiscectomy.

Introduction and importance: This case report describes resuscitative endovascular balloon occlusion (REBOA) of the aorta in a patient with life-threatening iatrogenic bleeding of the right common iliac artery during elective dorsal lumbar spine surgery. REBOA is an emergency procedure for temporary intra-aortic balloon occlusion being increasingly reported and published since its inauguration in 1954. The interdisciplinary management of hemorrhage and technical notes for a successful REBOA procedure will be presented. Case presentation: A 53-year-old female patient was admitted to the neurosurgery clinic suffering from left-sided L5 radiculopathy. During surgery, the anterior longitudinal ligament was perforated and an arterial vessel was lacerated. The patient became hemodynamically unstable demanding prompt supine repositioning and cardiopulmonary resuscitation (CPR). REBOA enabled cardiovascular stabilization after 90 min of CPR and laparotomy with vascular reconstruction and contributed to the survival of the patient without major clinical deficits. The patient was discharged from the ICU after 7 days. Clinical discussion: Resuscitative endovascular balloon occlusion of the aorta is an emergency procedure to control life-threatening hemorrhage. REBOA should be available on-scene and applied by well-trained vascular surgery personnel to control vascular complications or extend to emergency laparotomy and thoracotomy with aortic cross-clamping in case of in-hospital non-controllable hemorrhages. In case of ongoing CPR, we recommend surgical groin incision, open puncture of the pulseless common femoral artery, and aortic balloon inflation in REBOA zone I. Hereby, fast access and CPR optimization for heart and brain perfusion are maintained. Conclusion: Training for REBOA is the decisive factor to control selected cases of in-house and outpatient massive arterial abdominal bleeding complications.

Characteristics of patients with multiple arterial aneurysms.

Background: The aim of this retrospective cross-sectional observational study was to determine differences of patients with multiple arterial aneurysms to patients with single arterial aneurysms. Patients and methods: Patients with the diagnosis of an arterial aneurysm from January 2006 to January 2016 in the department of vascular surgery Heidelberg were investigated. Excluded were patients with hereditary disorders of connective tissue or systemic inflammatory disease, as well as other arterial pathologies than true aneurysms. Patients with multiple aneurysms (defined by at least four aneurysms) were compared to patients with single aneurysms concerning age at initial diagnosis, sex and affected arterial site. To verify the findings, a replication of the study was performed at a comparable institution. Results: Of 3107 patients with arterial aneurysms, 918 were excluded. Of the resulting 2189 patients, 1238 (56.6%) patients had a single, 808 (36.9%) two or three, and 143 (6.5%) at least four aneurysms (group mult-AA). Nine hundred seventy-two patients (44.4%) had a single abdominal aortic aneurysm (group sing-AAA). Age at initial diagnosis differed between mult-AA (66.7±9.5 y) and sing-AAA (69.1±8.6 y) (p=0.0338). Within mult-AA, 138 patients (96.5%) were male, compared with 865 patients (89.0%) in sing-AAA (p=0.0041). The most frequent aneurysm localization shifted from the abdominal aorta and its branches in patients with a single aneurysm (n=1029; 83.1%) to pelvic and leg arteries in patients with at least four aneurysms (n=318; 63.2%). The replication of the study at the department of vascular surgery Frankfurt confirmed the younger age at initial diagnosis in mult-AA (67.3±12.5 y) compared to sing-AAA (70.9±9.6 y) (p=0.0259) and the distribution shift toward the arteries below the aortic bifurcation in mult-AA. Conclusions: Patients with multiple aneurysms are younger at initial diagnosis and differ concerning aneurysm localization compared to patients with a single aneurysm.

Gene Expression Profiling in Abdominal Aortic Aneurysms.

Gene expression profiling of abdominal aortic aneurysms (AAA) indicates that chronic inflammatory responses, active matrix metalloproteinases, and degradation of the extracellular matrix components are involved in disease development and progression. This study investigates intra- and interpersonal RNA genome-wide expression profiling differences (Illumina HumanHT-12, BeadCHIP expression) of 24 AAA biopsies from 12 patients using a single gene and pathway (GeneOntology, GO enrichment) analysis. Biopsies were collected during open surgical AAA repair and according to prior finite element analysis (FEA) from regions with the highest and lowest wall stress. Single gene analysis revealed a strong heterogeneity of RNA expression parameters within the same and different AAA biopsies. The pathway analysis of all samples showed significant enrichment of genes from three different signaling pathways (integrin signaling pathway: fold change FC 1.63, p = 0.001; cholecystokinin receptor pathway: FC 1.60, p = 0.011; inflammation mediated by chemokine signaling pathway: FC 1.45, p = 0.028). These results indicate heterogeneous gene expression patterns within the AAA vascular wall. Single biopsy investigations do not permit a comprehensive characterization of activated molecular processes in AAA disease.

Multiple Arterial Dissections and Connective Tissue Abnormalities.

BACKGROUND: Although patients with multiple arterial dissections in distinct arterial regions rarely present with known connective tissue syndromes, we hypothesized that mild connective tissue abnormalities are common findings in these patients. METHODS: From a consecutive register of 322 patients with cervical artery dissection (CeAD), we identified and analyzed 4 patients with a history of additional dissections in other vascular beds. In three patients, dermal connective tissue was examined by electron microscopy. DNA from all four patients was studied by whole-exome sequencing and copy number variation (CNV) analysis. RESULTS: The collagen fibers of dermal biopsies were pathologic in all three analyzed patients. One patient carried a CNV disrupting the COL3A1 and COL5A2 genes (vascular or hypermobility type of Ehlers-Danlos syndrome), and another patient a CNV in MYH11 (familial thoracic aortic aneurysms and dissections). The third patient carried a missense substitution in COL5A2. CONCLUSION: Three patients showed morphologic alterations of the dermal connective tissue, and two patients carried pathogenic variants in genes associated with arterial connective tissue dysfunction. The findings suggest that genetic testing should be recommended after recurrent arterial dissections, independently of apparent phenotypical signs of connective tissue disorders.

Arterial Aneurysm Localization Is Sex-Dependent.

The aim of this study was to investigate sex-dependent aneurysm distributions. A total of 3107 patients with arterial aneurysms were diagnosed from 2006 to 2016. Patients with anything other than true aneurysms, hereditary connective tissue disorders or vasculitides (n = 918) were excluded. Affected arterial sites and age at first aneurysm diagnosis were compared between women and men by an unpaired two-tailed t-test and Fisher's exact test. The study sample consisted of 2189 patients, of whom 1873 were men (85.6%) and 316 women (14.4%) (ratio m:w = 5.9:1). Men had considerably more aneurysms in the abdominal aorta (83.4% vs. 71.1%; p < 0.001), common iliac artery (28.7% vs. 8.9%; p < 0.001), internal iliac artery (6.6% vs. 1.3%; p < 0.001) and popliteal artery (11.1% vs. 2.5%; p < 0.001). In contrast, women had a higher proportion of aneurysms in the ascending aorta (4.4% vs. 10.8%; p < 0.001), descending aorta (11.1% vs. 36.4%; p < 0.001), splenic artery (0.9% vs. 5.1%; p < 0.001) and renal artery (0.8% vs. 6.0%; p < 0.001). Age at disease onset and further aneurysm distribution showed no considerable difference. The infrarenal segment might be considered a natural border for aneurysm formation in men and women suspected to have distinct genetic, pathophysiologic and ontogenetic factors. Screening modalities for women at risk might need further adjustment, particularly thoracic cross-sectional imaging complementation.

Genetic Variation in LRP1 Associates with Stanford Type B Aortic Dissection Risk and Clinical Outcome.

Genetic variation in LRP1 (low-density lipoprotein receptor-related protein 1) was reported to be associated with thoracic aortic dissections and aneurysms. The aims of this study were to confirm this association in a prospective single-center patient cohort of patients with acute Stanford type B aortic dissections (STBAD) and to assess the impact of LRP1 variation on clinical outcome. The single nucleotide variation (SNV) rs11172113 within the LRP1 gene was genotyped in 113 STBAD patients and 768 healthy control subjects from the same population. The T-allele of rs11172113 was more common in STBAD patients as compared to the reference group (72.6% vs. 59.6%) and confirmed to be an independent risk factor for STBAD (p = 0.002) after sex and age adjustment in a logistic regression model analyzing diabetes, smoking and hypertension as additional risk factors. Analysis of clinical follow-up (median follow-up 2.0 years) revealed that patients with the T-allele were more likely to suffer aorta-related complications (T-allele 75.6% vs. 63.8%; p = 0.022). In this study sample of STBAD patients, variation in LRP1 was an independent risk factor for STBAD and affected clinical outcome.

Inflammasomes in the Pathophysiology of Aortic Disease.

Aortic diseases comprise aneurysms, dissections, and several other pathologies. In general, aging is associated with a slow but progressive dilation of the aorta, along with increased stiffness and pulse pressure. The progression of aortic disease is characterized by subclinical development or acute presentation. Recent evidence suggests that inflammation participates causally in different clinical manifestations of aortic diseases. As of yet, diagnostic imaging and surveillance is mainly based on ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). Little medical therapy is available so far to prevent or treat the majority of aortic diseases. Endovascular therapy by the introduction of covered stentgrafts provides the main treatment option, although open surgery and implantation of synthetic grafts remain necessary in many situations. Because of the risks associated with surgery, there is a need for identification of pharmaceutical targets interfering with the pathophysiology of aortic remodeling. The participation of innate immunity and inflammasome activation in different cell types is common in aortic diseases. This review will thus focus on inflammasome activities in vascular cells of different chronic and acute aortic diseases and discuss their role in development and progression. We will also identify research gaps and suggest promising therapeutic targets, which may be used for future medical interventions.

Acute Stanford type B aortic dissection-who benefits from genetic testing?

BACKGROUND: Stanford type B aortic dissection is a rare, life-threatening complex phenotype associated with several modifiable and genetic risk factors. In the current study of a hospital-based, consecutive series of aortic dissection patients we propose a selection based on age and family history of aortic disease for genetic testing and detection of causative gene variants. METHODS: In this single center cohort study from 2013 to 2018 patients with acute Stanford type B aortic dissections were consecutively treated and analyzed by next generation sequencing based on selection criteria (age of disease onset ≤45 years and/or positive familial history for aortic disease) to detect genome-wide pathogenic variants in protein-coding sequences and to identify large copy number variants (CNV). Variants in a predefined panel of 30 genes associated with the familial thoracic aortic aneurysm and dissection (TAAD) syndrome were evaluated. RESULTS: From 105 patients nine matched selection criteria for genetic testing. Next-generation sequencing analysis revealed causal variants in FBN1 (fibrillin-1) in three patients: a pathogenic missense variant [c.6661T>C, p.(Cys2221Arg)] and two truncating variants [c.4786C>T, p.(Arg1596Ter)] and [c.6366C>CA, p.(Asp2123GlufsTer5)]. A fourth patient carried a large (>1,000,000 bp) CNV in the long arm of chromosome 10, deleting eleven genes, including the whole ACTA2 (actin alpha 2) gene. The latter two genetic findings have not been reported before. CONCLUSIONS: Selection of patients on the basis of young age and familial inheritance of aortic disease favors the identification of disease-causing genetic variants in a clinical cohort of patients with Stanford type B aortic dissection.

Inflammasome activity in leucocytes decreases with abdominal aortic aneurysm progression.

Abdominal aortic aneurysms (AAAs) are characterized by chronic inflammatory cell infiltration. The present extended immunohistochemistry study aimed to characterize inflammation in AAA and aortic control samples. In specific, the composition of the infiltrating immune cells and the expression of five inflammasome components in these immune cells were evaluated, in order to characterize their role in AAA development. A total of 104 biopsies from 48 AAA patients and 40 healthy specimens from organ donors were evaluated for their grade of inflammation. Infiltrating leukocytes were characterized by specific markers (CD3, CD20 and CD68), intramural localization and inflammasome protein expression [NLR family pyrin domain containing 3 (NLRP3), absent in melanoma 2 (AIM2), apoptosis­associated speck­like protein containing a caspase recruitment domain (ASC), Caspase­1 and Caspase­5]. Macrophages, B and T lymphocytes were detected to a similar extent in grade 1, 2 and 3 AAA specimens, whereas in control samples, B and T lymphocytes were rarely observed in grade 1 lesions. Expression frequencies of NLRP3, AIM2 and Caspase­5 were significantly higher in grade 1 lesions of AAA samples compared with grade 1 lesions in control samples. Finally, AIM2, ASC, and Caspase­5 displayed significantly lower expression frequencies in grade 3 compared with grade 2 AAA specimens, and all inflammasome components were less frequently detected in grade 3 than in grade 1 lesions of AAA. This indicates that inflammasome activities decrease with AAA progression in infiltrating leukocytes. No statistically significant association was found for grade 2 and grade 3 lesions and total leukocyte count, C­reactive protein levels, maximal aortic diameter, plasma cholesterol level or biomechanical parameters (derived from finite element analysis) of the respective patients. Overall, the aortic wall of AAA contained lymphocytes and macrophages with different states of activity. The present data suggested that therapeutic inhibition of specific inflammasome components might counteract AAA development and progression.

Genetic Imbalance Is Associated With Functional Outcome After Ischemic Stroke.

Background and Purpose- We sought to explore the effect of genetic imbalance on functional outcome after ischemic stroke (IS). Methods- Copy number variation was identified in high-density single-nucleotide polymorphism microarray data of IS patients from the CADISP (Cervical Artery Dissection and Ischemic Stroke Patients) and SiGN (Stroke Genetics Network)/GISCOME (Genetics of Ischaemic Stroke Functional Outcome) networks. Genetic imbalance, defined as total number of protein-coding genes affected by copy number variations in an individual, was compared between patients with favorable (modified Rankin Scale score of 0-2) and unfavorable (modified Rankin Scale score of ≥3) outcome after 3 months. Subgroup analyses were confined to patients with imbalance affecting ohnologs-a class of dose-sensitive genes, or to those with imbalance not affecting ohnologs. The association of imbalance with outcome was analyzed by logistic regression analysis, adjusted for age, sex, stroke subtype, stroke severity, and ancestry. Results- The study sample comprised 816 CADISP patients (age 44.2±10.3 years) and 2498 SiGN/GISCOME patients (age 67.7±14.2 years). Outcome was unfavorable in 122 CADISP and 889 SiGN/GISCOME patients. Multivariate logistic regression analysis revealed that increased genetic imbalance was associated with less favorable outcome in both samples (CADISP: P=0.0007; odds ratio=0.89; 95% CI, 0.82-0.95 and SiGN/GISCOME: P=0.0036; odds ratio=0.94; 95% CI, 0.91-0.98). The association was independent of age, sex, stroke severity on admission, stroke subtype, and ancestry. On subgroup analysis, imbalance affecting ohnologs was associated with outcome (CADISP: odds ratio=0.88; 95% CI, 0.80-0.95 and SiGN/GISCOME: odds ratio=0.93; 95% CI, 0.89-0.98) whereas imbalance without ohnologs lacked such an association. Conclusions- Increased genetic imbalance was associated with poorer functional outcome after IS in both study populations. Subgroup analysis revealed that this association was driven by presence of ohnologs in the respective copy number variations, suggesting a causal role of the deleterious effects of genetic imbalance.

Familial aortic disease and a large duplication in chromosome 16p13.1.

BACKGROUND AND PURPOSE: A recurrent duplication of chromosome 16p13.1 was associated with aortic dissection as well as with cervical artery dissection. We explore the segregation of this duplication in a family with familial aortic disease. METHODS: Whole exome sequencing (WES) analysis was performed in a patient with a family history of aortic diseases and ischemic stroke due to an aortic dissection extending into both carotid arteries. RESULTS: The index patient, his affected father, and an affected sister of his father carried a large duplication of region 16p13.1, which was also verified by quantitative PCR. The duplication was also found in clinically asymptomatic sister of the index patient. WES did not detect pathogenic variants in a predefined panel of 11 genes associated with aortic disease, but identified rare deleterious variants in 14 genes that cosegregated with the aortic phenotype. CONCLUSIONS: The cosegregation of duplication 16p13.1 with the aortic phenotype in this family suggested a causal relationship between the duplication and aortic disease. Variants in known candidate genes were excluded as disease-causing in this family, but cosegregating variants in other genes might modify the contribution of duplication 16p13.1 on aortic disease.

Gene Expression Profiling in Abdominal Aortic Aneurysms After Finite Element Rupture Risk Assessment.

PURPOSE: To investigate the association between local biomechanical rupture risk calculations from finite element analysis (FEA) and whole-genome profiling of the abdominal aortic aneurysm (AAA) wall to determine if AAA wall regions with highest and lowest estimated rupture risk show different gene expression patterns. METHODS: Six patients (mean age 74 years; all men) scheduled for open surgery to treat asymptomatic AAAs (mean diameter 55.2±3.5 mm) were recruited for the study. Rupture risk profiles were estimated by FEA from preoperative computed tomography angiography data. During surgery, AAA wall samples of ~10 mm2 were extracted from the lowest and highest rupture risk locations identified by the FEA. Twelve samples were processed for RNA extraction and subsequent whole genome expression profiling. Expression of single genes and of predefined gene groups were compared between vessel wall areas with highest and lowest predicted rupture risk. RESULTS: Normalized datasets comprised 15,079 gene transcripts with expression above background. In biopsies with high rupture risk, upregulation of 18 and downregulation of 18 genes was detected when compared to the low-risk counterpart. Global analysis of predefined gene groups revealed expression differences in genes associated with extracellular matrix (ECM) degradation (p<0.001), matrix metalloproteinase activity (p<0.001), and chemokine signaling (p<0.001). CONCLUSION: Increased expression of genes involved in degrading ECM components was present in AAA wall regions with highest biomechanical stress, supporting the thesis of mechanotransduction. More experimental studies with cooperation of multicenter vascular biobanks are necessary to understand AAA etiologies and identify further parameters of FEA model complementation.

Next generation sequencing analysis of patients with familial cervical artery dissection.

BACKGROUND: The cause of cervical artery dissection is not well understood. We test the hypothesis that mutations in genes associated with known arterial connective tissue disorders are enriched in patients with familial cervical artery dissection. PATIENTS AND METHODS: Patient duos from nine pedigrees with familial cervical artery dissection were analyzed by whole exome sequencing. Single nucleotide variants in a panel of 11 candidate genes (ACTA2, MYH11, FBN1, TGFBR1, TGFBR2, TGFB2, COL3A1, COL4A1, SMAD3, MYLK and SLC2A10) were prioritized according to functionality (stop-loss, nonsense, and missense variants with polyphen-2 score ≥0.95). Variants classified as "benign" or "likely benign" in the ClinVar database were excluded from further analysis. For comparison, non-benign stop-loss, nonsense and missense variants with polyphen-2 score ≥0.95 in the same panel of candidate genes were identified in the European non-Finnish population of the ExAC database (n = 33,370). RESULTS: Non-benign Single nucleotide variants in both affected patients were identified in four of the nine cervical artery dissection families (COL3A1; Gly324Ser, FBN1: Arg2554Trp, COL4A1: Pro116Leu, and TGFBR2: Ala292Thr) yielding an allele frequency of 22.2% (4/18). In the comparison group, 1782 variants were present in 33,370 subjects from the ExAC database (allele frequency: 1782/66,740 = 2.7%; p = 0.0008; odds ratio = 14.2; 95% confidence interval = 3.8-52.9). CONCLUSION: Cervical artery dissection families showed enrichment for non-benign variants in genes associated with arterial connective tissue disorders. The observation that findings differed across families indicates genetic heterogeneity of familial cervical artery dissection.