Descending Aorta Research Articles

Which is the proper reference tissue for measuring the change in FDG PET metabolic volume of cardiac sarcoidosis before and after steroid therapy?

BackgroundCardiac sarcoidosis (CS) is a rare but potentially life-threatening disease that causes conduction disturbance, systolic dysfunction, and, most notably, sudden cardiac death. 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) plays important roles not only in diagnosing CS but also in evaluating the effects of anti-inflammatory therapy. A volume-based analysis of parameters measured by FDG PET, so-called cardiac metabolic volume (CMV), has emerged as a new assessment tool. CMV is measured as the volume within the boundary determined by a reference tissue such as the liver and the blood pool uptake. However, there is a possibility that oral steroid therapy could lead to variations of the liver and the blood pool uptake. Here, we attempted to evaluate the steroid effects on the liver and the blood pool uptake.A total of 38 CS patients who underwent FDG PET/CT before and during steroid therapy were retrospectively enrolled. Volumes of interest (VOIs) were placed in the right lobe of the liver and descending aorta (DA). The maximum standardized uptake value (SUVmax), SUVmean, and SUVpeak of the liver and DA were compared between time points before and during steroid therapy.ResultsThe SUVmax, SUVmean, and SUVpeak of the liver during steroid therapy significantly increased from the time point before the therapy (SUVmax 3.5 ± 0.4 vs. 3.8 ± 0.6, p = 0.014; SUVmean 2.7 ± 0.3 vs. 3.0 ± 0.5, p = 0.0065; SUVpeak 3.0 ± 0.4 vs. 3.4 ± 0.6, p = 0.006). However, the SUVmax, SUVmean, and SUVpeak in the DA did not significantly change (SUVmax 2.2 ± 0.3 vs. 2.2 ± 0.4, p = 0.46; SUVmean 1.9 ± 0.3 vs. 2.0 ± 0.4, p = 0.56; SUVpeak 2.0 ± 0.3 vs. 2.0 ± 0.3, p = 0.70).ConclusionsWe measured FDG uptake in the liver and blood pool before and during steroid therapy. Steroid therapy increased the liver uptake but not the blood pool uptake. Our findings suggested that the DA uptake is a more suitable threshold than liver uptake to evaluate therapeutic effects using volume-based analysis of cardiac FDG PET.

Metformin Improves Insulin Resistance (IR) and Vascular Health in Youth with Type 1 Diabetes (T1D)

Cardiovascular disease is the leading cause of mortality in T1D and relates to IR. We demonstrated that lean and obese T1D youth have IR and that metformin improves surrogate markers of IR in obese T1D youth. Yet, little is known about vascular health in T1D youth or about the effect of metformin on directly-measured IR or vascular health. In The Effects of MEtformin on cardiovasculaR function in AdoLescents with type 1 Diabetes (EMERALD) study, we hypothesized that T1D youth have impaired vascular function and that metformin decreases IR and improves vascular health. 49 T1D youth ages 12-21 years (40% with BMI ≥ 90%ile; 44% male) and 24 controls of similar age, BMI and sex underwent phase contrast MRI of the ascending (AA) and descending aorta (DA) to determine aortic pulse wave velocity (PWV) and wall shear stress (WSS). T1D youth also had carotid intima-media thickness (cIMT) by ultrasound, DXA scan, fasting labs following overnight IV glycemic control, and a hyperinsulinemic-euglycemic clamp (80 mU/m2/min insulin) to assess IR (glucose infusion rate [mg/kg/min)]/insulin or M/I). T1D youth were then randomized 1:1 to 2g of metformin or placebo daily, and all measures repeated at 3 months. At baseline, T1D youth vs. controls had elevated aortic PWV (AA: 3.7±0.2 vs. 2.5±0.4 m/s, p<0.05; DA: 4.2±0.2 vs. 3.1±0.3 m/s, p=0.02) and WSS (AA: 1.1±0.04 vs. 0.9±0.N/m2, p=0.003; DA: 1.6±0.vs. 1.1±0.07 N/m2, p<0.0001). Compared to the placebo group, T1D youth in the metformin group had no baseline differences but had improvement at 3 months in M/I (12.2±3.2 vs. -2.4±3.6 uIU/uL, p<0.01), AA PWV (-1.1±1.1 vs. 4.1±1.6 m/s, p<0.04), AA WSS (-0.03±0.04 vs. 0.2±0.N/m2, p<0.03) and far wall diastolic cIMT (-0.04±0.01 vs. 0.00±0.01 mm, p=0.04) in baseline-adjusted models. T1D youth have IR and vascular dysfunction compared to controls of similar age, sex and BMI. Metformin mitigated IR and improved aortic and carotid health in T1D youth, and thus may hold promise as a cardiovascular protective intervention. Disclosure K.J. Nadeau: None. P. Bjornstad: Consultant; Self; Boehringer Ingelheim GmbH. M. Sch fer: None. L. Browne: None. A. Baumgartner: None. Y. Garcia Reyes: None. A. Maniatis: None. R. Wadwa: Advisory Panel; Self; Eli Lilly and Company. Research Support; Self; MannKind Corporation, Dexcom, Inc., Xeris Pharmaceuticals, Inc., Bigfoot Biomedical. S. Nayak: None. L. Pyle: None. M. Cree-Green: None. J.E. Reusch: Research Support; Self; Merck & Co., Inc.. Board Member; Self; American Diabetes Association. Research Support; Self; AstraZeneca. Other Relationship; Self; Sanofi-Aventis.

ABNORMAL FLOW PATTERN AND GEOMETRY ARE INTERRELATED AND CONTRIBUTE TO PROXIMAL DESCENDING AORTA DILATION IN MARFAN PATIENTS

Objective: Marfan syndrome (MFS) is a hereditary connective tissue disorder caused by mutation in the FBN1 gene. Diseases of the ascending aorta (AAo), like dilation or type A dissection, are very prevalent. However, after improvements in the surgical AAo management, diseases of the descending aorta (DAo) emerged as a clinical issue. Recent qualitative studies in MFS have revealed the existence of abnormal vortex in the proximal DAo which were related to local dilation. However, any study has investigated the origin of these vortices. The aim of the present investigation was to investigate the relationship between aortic geometry and abnormal flow characteristics in the thoracic aorta of MFSDesign and method: Fifty-tree confirmed MFS patients without congenital heart diseases or aortic valve disease were prospectively included from our Aortic unit. Also, 40 age-matched healthy volunteers (HV) were recruited. All participants underwent non-contrast-enhanced 4D flow-MRI, obtaining flow field and angiography. Geometric parameters (diameter, ellipticity and curvature) and rotational flow characteristics (in-plane rotational flow IRF, systolic flow reversal ratio SFRR) were evaluated (see figure 1) at 20 planes through the thoracic aorta. Results: Aortic diameters were significantly-larger in MFS in the proximal AAo (p < 0.001) and in the proximal DAo (p = 0.028) compared to HV, while no differences were found in the remaining region. Ellipticity was increased and peak of aortic curvature was larger and more distal in MFS compared to controls (figure 2) Rotational flow (IRF, related to helicity) was reduced in MFS patients in the majority of the thoracic aorta, while SFRR (backward systolic flow) was increased in the proximal AAo and DAo. Bivariate correlation showed inverse relation between arch ellipticity (R = −0.34, p = 0.016) as well as proximal DAo peak curvature (R = −0.35, p = 0.015) and arch IRF. Maximum proximal DAo diameter was negatively correlated with local IRF (R = −0.3, p = 0.038) and positively correlated with local SFRR (R = 0.605, p < 0.001). Conclusions: Abnormal aortic ellipticity and curvature were evident in MFS patients and related to a reduction of flow helicity and increase of vorticity in the DAo. Longitudinal studies are needed to investigate eventual prognostic value of aortic geometry and flow in MFS patients.

Influence of Aortic Dilation on the Regional Aortic Stiffness of Bicuspid Aortic Valve Assessed by 4-Dimensional Flow Cardiac Magnetic Resonance: Comparison With Marfan Syndrome and Degenerative Aortic Aneurysm

ObjectivesThis study sought to ascertain whether patients with a bicuspid aortic valve (BAV) have an intrinsic alteration in regional aortic stiffness compared with patients with tricuspid aortic valve (TAV) and Marfan syndrome (MFS) patients with similar aortic sizes, as well as to assess the influence of ascending aorta (AAo) dilation on regional stiffness parameters in BAV patients. BackgroundImaging biomarkers as predictors of BAV, MFS, and degenerative AAo aneurysms in TAV patients (DA-TAV) are lacking. Biomechanical characterization has been proposed as a possible tool for further aneurysm stratification. MethodsA total 234 subjects (136 BAV, 44 MFS, and 18 DA-TAV patients and 36 healthy control subjects) were included. The cardiac magnetic resonance protocol comprised 4-dimensional flow to assess AAo and descending aorta (DAo) pulse wave velocities (PWVs) and double-oblique, 2-dimensional, steady-state free-precession cine cardiac magnetic resonance to compute aortic distensibility (AD). ResultsOn adjusted analysis, nondilated BAV patients had similar PWV and AD as healthy control subjects in both AAo and DAo, whereas dilated BAV did not differ from DA-TAV. In contrast, AAo and DAo stiffness in MFS patients was markedly greater than in BAV patients, increasing slightly with dilation severity. AAo PWV showed a biphasic pattern in BAV patients: it first decreased and then increased throughout AAo dilation, with a clear turning point at 50 mm, whereas distensibility did not discern mildly dilated aorta. In multivariate analysis adjusted for clinical and demographic characteristics, only PWV was related to AAo dilation in BAV patients. ConclusionsThe mechanical properties of AAo aneurysms are similar in BAV and TAV patients, whereas MFS patients have a stiffer aorta. Aortic stiffness strongly depends on dilation severity. AAo PWV resulted in a potentially clinically useful biphasic trend with respect to aneurysm diameter, whereas distensibility did not discern mildly dilated aorta. Beyond clinical risk factors, PWV but not AD was independently related to AAo dilation in BAV patients.

Automatic tube potential selection with tube current modulation in coronary CT angiography: Can it achieve consistent image quality among various individuals?

The present study included a total of 111 consecutive patients who had undergone coronary computed tomography (CT) angiography, using a first-generation dual-source CT with automatic tube potential selection and tube current modulation. Body weight (BW) and body mass index (BMI) were recorded prior to CT examinations. Image noise and attenuation of the proximal ascending aorta (AA) and descending aorta (DA) at the middle level of the left ventricle were measured. Correlations between BW, BMI and objective image quality were evaluated using linear regression. In addition, two subgroups based on BMI (BMI ≤25 and >25 kg/m2) were analyzed. Subjective image quality, image noise, the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) were all compared between those. The image noise of the AA increased with the BW and BMI (BW: r=0.453, P<0.001; BMI: r=0.545, P<0.001). The CNR and SNR of the AA were inversely correlated with BW and BMI, respectively. The image noise of the DA and the CNR and SNR of the DA exhibited a similar association to those with the BW or BMI. The BMI >25 kg/m2 group had a significant increase in image noise (33.1±6.9 vs. 27.8±4.0 HU, P<0.05) and a significant reduction in CNR and SNR, when compared with those in the BMI ≤25 kg/m2 group (CNR: 18.9±4.3 vs. 16.1±3.7, P<0.05; SNR: 16.0±3.8 vs. 13.6±3.2, P<0.05). Patients with a BMI of ≤25 kg/m2 had more coronary artery segments scored as excellent, compared with patients with a BMI of >25 kg/m2 (P=0.02). In conclusion, this method is not able to achieve a consistent objective image quality across the entire patient population. The impact of BW and BMI on objective image quality was not completely eliminated. BMI-based adjustment of the tube potential may achieve a more consistent image quality compared to automatic tube potential selection, particularly in patients with a larger body habitus.

Computational study of aortic hemodynamics for patients with an abnormal aortic valve: The importance of secondary flow at the ascending aorta inlet.

Blood flow in the aorta is helical, but most computational studies ignore the presence of secondary flow components at the ascending aorta (AAo) inlet. The aim of this study is to ascertain the importance of inlet boundary conditions (BCs) in computational analysis of flow patterns in the thoracic aorta based on patient-specific images, with a particular focus on patients with an abnormal aortic valve. Two cases were studied: one presenting a severe aortic valve stenosis and the other with a mechanical valve. For both aorta models, three inlet BCs were compared; these included the flat profile and 1D through-plane velocity and 3D phase-contrast magnetic resonance imaging derived velocity profiles, with the latter being used for benchmarking. Our results showed that peak and mean velocities at the proximal end of the ascending aorta were underestimated by up to 41% when the secondary flow components were neglected. The results for helical flow descriptors highlighted the strong influence of secondary velocities on the helical flow structure in the AAo. Differences in all wall shear stress (WSS)-derived indices were much more pronounced in the AAo and aortic arch (AA) than in the descending aorta (DAo). Overall, this study demonstrates that using 3D velocity profiles as inlet BC is essential for patient-specific analysis of hemodynamics and WSS in the AAo and AA in the presence of an abnormal aortic valve. However, predicted flow in the DAo is less sensitive to the secondary velocities imposed at the inlet; hence, the 1D through-plane profile could be a sufficient inlet BC for studies focusing on distal regions of the thoracic aorta.

Cross-sectional Areas of the Thoracic Aorta in Children and Adolescents With Repaired Tetralogy of Fallot Obtained by Cardiac Magnetic Resonance Angiography

Dilatation of the thoracic aorta is a well-known finding in corrected Tetralogy of Fallot. Complications are rare but can be life-threatening. Standard 1-dimensional (1D) measurements have several limitations. We sought to establish contrast-enhanced magnetic resonance angiography cross-sectional areas of the aorta that could serve as reference values and to identify parameters that are associated with aortic dilatation. We enrolled 101 children and adolescents. The aortic areas were measured at the level of the aortic sinus (AS), the sinotubular junction (STJ), the ascending aorta (AA), the brachiocephalic trunk (TBC), and the descending aorta (DA). Sex-specific aortic dimensions were presented as percentile curves as well as regression equations. Furthermore volumetric and functional parameters as well as clinical data were analyzed to identify parameters that are associated with aortic dilatation. Aortic areas (mm) for female subjects were 139+366×body surface area (BSA) for the AS, 134+255×BSA for the STJ, 113+239×BSA for the AA, 88+185×BSA proximal to the TBC, and 2.9+88×BSA for the DA. Aortic areas (mm) for male subjects were 162+403×BSA for the AS, 171+258×BSA for the STJ, 151+233×BSA for the AA, 73+206×BSA proximal to the TBC, and 21+80×BSA for the DA. The postoperative interval and age at examination were parameters associated with aortic size. We provide aortic areas in children and adolescents after correction of Tetralogy of Fallot measured by contrast-enhanced magnetic resonance angiography. Our 2D data may better depict the geometry of enlarged aortae than standard 1D diameters and serve as reference values for evaluating aortic disease in these patients.

Determination of aortic stiffness using 4D flow cardiovascular magnetic resonance - a population-based study

BackgroundIncreased aortic stiffness is an independent predictor of cardiovascular disease. Optimal measurement is highly beneficial for the detection of atherosclerosis and the management of patients at risk. Thus, it was our purpose to selectively measure aortic stiffness using a novel imaging method and to provide reference values from a population-based study.MethodsOne hundred twenty six inhabitants of Freiburg, Germany, between 20 and 80 years prospectively underwent 3 Tesla cardiovascular magnetic resonance (CMR) of the thoracic aorta. 4D flow CMR (spatial/temporal resolution 2mm3/20ms) was executed to calculate aortic pulse wave velocity (PWV) in m/s using dedicated software. In addition, we calculated distensibility coefficients (DC) using 2D CINE CMR imaging of the ascending (AAo) and descending aorta (DAo). Segmental aortic diameter and thickness of aortic plaques were determined by 3D T1 weighted CMR (spatial resolution 1mm3).ResultsPWV increased from 4.93 ± 0.54 m/s in 20–30 year-old to 8.06 ± 1.03 m/s in 70–80 year-old subjects. PWV was significantly lower in women compared to men (p < 0.0001). Increased blood pressure (systolic r = 0.36, p < 0.0001; diastolic r = 0.33, p = 0.0001; mean arterial pressure r = 0.37, p < 0.0001) correlated with PWV after adjustment for age and gender. Finally, PWV increased with increasing diameter of the aorta (ascending aorta r = 0.20, p = 0.026; aortic arch r = 0.24, p = 0.009; descending aorta r = 0.26, p = 0.004). Correlation of PWV and DC of the AAo and DAo or the mean of both was high (r = 0.69, r = 0.68, r = 0.73; p < 0.001).Conclusions4D flow CMR was successfully applied to calculate aortic PWV and thus aortic stiffness. Findings showed a high correlation with distensibility coefficients representing local compliance of the aorta. Our novel method and reference data for PWV may provide a reliable biomarker for the identification of patients with underlying cardiovascular disease and optimal guidance of future treatment in studies or clinical routine.

Interrupted right-sided aortic arch: performance of umbilical xenograft after primary neonatal corrective surgery

Interrupted aortic arch (IAA) associated with right-sided aorta descendens is a rare congenital malformation. We present a case of a female patient who was diagnosed with type B IAA and received primary corrective surgery as a neonate. A bovine umbilical vascular graft was used to establish aortic arch continuity. Thirty-nine years later the same patient presents with graft-dilatation and a distal aneurysm requiring a surgery. This case shows a late complication of a biological xenograft in term of long-term material performance. Moreover, it highlights the necessity for regular follow-ups in order to detect and treat late onset complications respectively.

4D flow MRI, cardiac function, and T1 -mapping: Association of valve-mediated changes in aortic hemodynamics with left ventricular remodeling.

Patients with bicuspid aortic valve (BAV) show altered hemodynamics in the ascending aorta that can be assessed by 4D flow MRI. Comprehensive cardiac MRI was applied to test the hypothesis that BAV-mediated changes in aortic hemodynamics (wall shear stress [WSS] and velocity) are associated with parameters of left ventricular (LV) remodeling. Retrospective data analysis. Forty-nine BAV patients (mean age = 50.2 ± 13.5, 62% male). Balanced steady-state free precession (bSSFP)-CINE, pre- and postcontrast T1 mapping with modified Look-Locker inversion recovery (MOLLI), time-resolved 3D phase-contrast (PC) MRI with three-directional velocity encoding (4D flow MRI) at 1.5 and 3T. Quantification of LV volumetric data and myocardial mass, extracellular volume fraction (ECV), aortic valve stenosis (AS), and regurgitation (AR). 3D aortic segmentation, quantification of peak systolic velocities, and 3D WSS in the ascending aorta (AAo), arch, and descending aorta (DAo). Two-sided nonpaired t-test to compare subgroups. Pearson correlation coefficient for correlations between aortic hemodynamics and LV parameters. Of the 49 BAV patients, 35 had aortic valve dysfunction (AS [n = 7], AR [n = 16], both AS and AR [n = 12]). Mean systolic WSS in the AAo, peak systolic velocities in the AAo and arch, and LV mass were significantly higher (P < 0.001) in the AS/AR group compared to the patients without AS/AR. In the complete group, we observed significant relationships between increased LV mass and elevated peak systolic velocity (r = 0.57, r = 0.58; P < 0.001) and WSS in the AAo and arch, respectively (r = 0.54, r = 0.46; P < 0.001). We detected an association between ECV and WSS in the AAo (r = 0.38, P = 0.02). These relations did not hold true for patients without AV dysfunction. AS and AR in BAV patients have a major impact on elevated aortic peak velocities and WSS that were associated with parameters of LV remodeling. 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017.

Low Peak dP/dt in the Descending Aorta in Patients After Successful Aortic Arch Repair.

One of the most important problems in patients with aortic coarctation or interruption of the aortic arch after successful aortic arch repair is developing cardiovascular disease in the future. It has been reported that the repaired site is stiff and generates a new pressure wave reflection, which could lead to cardiovascular disease. The purpose of this study was to clarify the influence of the repaired portion's stiffness on the pressure waveform in patients. Fifteen patients (age: 7.4 ± 3.2years) who had successful aortic arch repair were enrolled. Their peak dP/dt in the ascending aorta (AAo) and the descending aorta (DAo) were compared with those of age-matched controls with a normal aortic arch. The ascending and descending aortic systolic blood pressures in aortic arch repair patients were higher than those in age-matched controls (AAo: 103.1 ± 13.3 vs. 91.9 ± 9.2mmHg, p = 0.012 and DAo: 108.7 ± 16.4 vs. 96.5 ± 9.9mmHg, p = 0.020). Although no difference existed in the peak dP/dt in the AAo between the aortic arch repair patients and the controls (572.1 ± 100.1 vs. 543.3 ± 110.2mmHg/s, p = 0.460), the peak dP/dt in the DAo in the aortic arch repair patients was significantly lower than that in the controls (489.3 ± 75.2 vs. 579.4 ± 106.0mmHg/s, p = 0.013). The peak dP/dt in the DAo in aortic arch repair patients is low. The stiff repaired site may attenuate pulsation.

Value of three-vessel and trachea view plus aortic arch coronal section in ultrasonic diagnosis and classification of fetal right aortic arch

Objective To explore the value of three-vessel and trachea(3VT) view plus aortic arch coronal section in ultrasonic diagnosis and classification of fetal right aortic arch(RAA). Methods Echocardiography data and follow-up results of 44 fetuses with RAA were retrospectively analyzed. Sonographic features on 3VT view and aortic arch coronal section were summarized. Results Among 44 fetuses with RAA, 27 cases(61.36%) were RAA with aberrant left subclavian artery(ALSA) and the left ductus arteriosus(LDA) connecting the ALSA and U-shaped vascular ring was formed; 17 cases(38.64%) were mirror right aortic arch(MRAA). Among 17 cases with MRAA, 3 cases were with LDA connecting the descending aorta(DAO) and U-shaped vascular ring was formed; 1 case was with LDA connecting the left innominate artery(LINA), 8 cases were with absent ductus arteriosus(ADA), 5 case were with right ductus arteriosus(RDA), no vascular ring was formed. Parts of MRAA were combined with other complex intracardiac abnormalities. RAA-ALSA-LDA were rarely combined with intracardiac abnormalities. Conclusions 3VT view is simple and intuitive for diagnosing RAA. Aortic arch coronal section has great clinical value in determining the concrete type of RAA. Key words: Echocardiography; Fetus; Aortic disease; Three-vessel and trachea view; Aortic arch coronal section

Association of descending thoracic aortic plaque with brain atrophy and white matter hyperintensities: The Framingham Heart Study

Background and aimsAortic atherosclerosis is an aggregate marker of vascular risk factor exposure and has been associated with intracranial atherosclerosis and stroke. We hypothesized that atherosclerosis of the descending aorta (DAo) could be a risk marker for brain aging and injury. MethodsWe evaluated 1527 participants (mean age 59.9 years, 53.5% women) in the Framingham Offspring cohort who underwent both aortic and brain MRI. Participants were free of clinical stroke, dementia, or other neurological illness at the time of axial MRI of the thoracic and abdominal DAo and subsequent brain MRI. We related the prevalence and burden of aortic plaque to total cerebral brain volume (TCBV) and white matter hyperintensity volume (WMHV). An additional analysis compared incidence of stroke or TIA in participants with and without DAo plaques. ResultsPresence of thoracic DAo plaque (8%) was associated with decreased TCBV in sex-pooled analysis (−0.77, SE 0.25, p = 0.002, equivalent to 4.5 years of aging) and with increased WMHV only in men (0.26, SE 0.12, p = 0.032, equivalent to 6.5 years aging). We observed similar associations of DAo plaque burden with TCBV and WMHV. There were 43 strokes and 11 TIAs in prospective follow-up (median 7 years). Presence of DAo plaque was not associated with subsequent stroke or TIA. ConclusionsIn this cross-sectional community-based study, we found DAo plaque is associated with accelerated brain aging. These data underscore the potential implications of incidentally identified subclinical aortic atherosclerosis and question whether targeted intervention in these high risk individuals can modulate cognitive decline.

Vascular geometry as a risk factor for non-penetrating traumatic injuries of the aortic arch.

PurposeTo assess biomechanical factors in aortic arch geometry contributing to the development of non-penetrating aortic arch injury (NAAI) in multiply injured patients with an Injury Severity Score (ISS) ≥ 16.Material and methods230 consecutive multiply injured trauma patients with an ISS ≥ 16 admitted to our Level-I trauma center during a consecutive 24-month period were prospectively included of whom 13 presented with NAAI (5.7%). Standardized whole-body CT in a 2x128-detector-row scanner included a head-and-neck CTA. Aortic arch diameters, width, height, angles and thoracic width and height were measured in individuals with NAAI and ISS-, sex-, age-, and trauma mechanism-matched controls.ResultsThere was no difference between groups regarding sex, age, ISS, and aortic diameters. The aortic arch angle in individuals with NAAI (71.3° ± 14.9°) was larger than in healthy control (60.7° ± 8.6°; p*<0.05). In patients with NAAI, the distance between ascendent and descendent aorta was larger (5.2 cm ± 1.9 cm) than in control (2.8 ± 0.5 cm; ***p<0.001). The aortic arch is higher above tracheal bifurcation in NAAI (3.6 cm ± 0.6 cm) than in matched control (2.4 cm ± 0.3 cm; ***p<0.001). Accordingly, the area under the aortic arch, calculated as half of an eliptic shape, is significantly larger in patients with NAAI (15.0 cm2 ± 6.5 cm2) when compared to age- and sex-matched controls without NAAI (5.5 cm2 ± 1.3 cm2; ***p<0.001).ConclusionBesides the magnitude of deceleration and direction of impact, width and height of the aortic arch are the 3rd and 4th factor directly contributing to the risk of developing traumatic NAAI in severely injured patients.

Safety and Feasibility of the Transcatheter Approach to Create a Reverse Potts Shunt in Children With Idiopathic Pulmonary Arterial Hypertension

BackgroundThe reversed Potts shunt improves right ventricular (RV) function in patients with suprasystemic pulmonary arterial hypertension (PAH). The proximity of the left pulmonary artery (LPA) to the descending aorta (DAo) permits the creation of a transcatheter connection. We sought to assess the safety, feasibility, and hemodynamic efficacy of the transcatheter Potts shunt (TPS) in children. MethodsThe TPS procedure was performed using radiofrequency energy for vessel perforation and deployment of a covered stent to connect the DAo and LPA. Procedural details and clinical follow-up data were collected prospectively. ResultsA TPS was successfully created in 6 children (mean age, 11.0 ± 4.2 years) with drug-refractory suprasystemic PAH and deteriorating RV function. All patients exhibited nearly complete equalization of aortic and pulmonary pressures and improvement in RV contractility within days after TPS placement. Two patients with pre-existing severe biventricular dysfunction and pericardial effusion experienced acute low-output states immediately after shunt creation because of sudden reductions in left ventricular (LV) preload, resulting in cardiac arrest, irreversible brain damage, and death. Stent dislodgement and embolization into the iliac artery occurred in 1 patient. The stent was successfully secured and followed by placement of a second stent at the target location. The procedure was uncomplicated in 4 patients, who remain alive after a mean follow-up of 10 ± 2.6 months. Intravenous vasodilator therapy was weaned uneventfully after TPS in 3 patients. ConclusionsTPS creation in children is feasible and results in hemodynamic improvement. Further insights into high-risk markers, such as reduced preprocedural LV function and preload reserves, are important for guiding patient selection.

Importance of variants in cerebrovascular anatomy for potential retrograde embolization in cryptogenic stroke.

To test the hypothesis that variants in cerebrovascular anatomy will affect the number of patients demonstrating a plausible retrograde embolization mechanism from plaques in the descending aorta (DAo). Thirty-five patients (aged 63 ± 17years) with cryptogenic stroke underwent 4D flow MRI for the assessment of aortic 3D blood flow and MR angiography for the evaluation of circle of Willis, posterior circulation, and aortic arch architecture. In patients with proven DAo plaque, retrograde embolization was considered a potential mechanism if retrograde flow extended from the DAo to a supra-aortic vessel supplying the cerebral infarct territory. Retrograde embolization with matching cerebral infarct territory was detected in six (17%) patients. Circle of Willis and aortic arch variant anatomy was found in 60% of patients, leading to reclassification of retrograde embolization risk as present in three (9%) additional patients, for a total 26% of cryptogenic stroke patients. 4D flow MRI demonstrated 26% concordance with infarct location on imaging with retrograde diastolic flow into the feeding vessels of the affected cerebral area, identifying a potential etiology for cryptogenic stroke. Our findings further demonstrate the importance of cerebrovascular anatomy when determining concordance of retrograde flow pathways with vascular stroke territory from DAo plaques. • Retrograde embolization from descending aortic plaques constitutes a plausible etiology in cryptogenic stroke. • Common variants of cerebrovascular anatomy are important in determining retrograde embolization mechanism. • Variant cerebrovascular anatomy can link retrograde flow pathways with vascular stroke territory.

Pro‐atherogenic disturbed flow increases endothelial stiffness via enhanced CD36/Cav1‐ mediated oxLDL uptake

ObjectiveDisturbed flow (DF) is known to induce endothelial dysfunction and synergistically with plasma dyslipidemia promote plaque formation. Little is known, however, about the synergistic impact of DF and dyslipidemia on endothelial biomechanical properties. Our goal was to determine the impact of DF on endothelial stiffness and evaluate the role of dyslipidemia/oxidized low density lipoprotein (oxLDL) in this process.Methods and ResultsEndothelial elastic modulus of intact mouse aortas ex vivo and of human aortic ECs (HAECs) exposed to laminar or disturbed flow in vitro was measured using atomic force microscopy. The endothelial monolayer of the aortic arch (AA) was found to be significantly stiffer than the descending aorta (DA) (4.2+1.1 vs. 2.5+0.2 kPa for AA vs. DA) in mice maintained on low fat diet (LFD). This effect was significantly exacerbated by a short‐term high‐fat diet (HFD) (8.7+2.5 vs. 4.5+1.2 kPa for AA vs. DA). Exposure of HAECs to DF in vitro resulted in a 50% increase in oxLDL uptake and significant endothelial stiffening in the presence but not in the absence of oxLDL. DF was shown to increase the expression of oxLDL receptor CD36 and the downregulation of CD36 abrogated DF‐induced endothelial oxLDL uptake and stiffening. ECs deficient in caveolin1 (Cav1) had no significant oxLDL uptake and no DF‐induced EC stiffening. Furthermore, genetic deficiencies of CD36 and of Cav1 abrogated endothelial stiffening in the aortic arch ex vivo in mice fed either LFD or HFD.ConclusionsDisturbed flow facilitates endothelial CD36/Cav1‐dependent uptake of oxidized lipids resulting in a local increase of endothelial stiffness in pro‐atherogenic areas of the aorta.Support or Funding InformationThis study is supported by NIH grants HL‐073965 (IL,DE), HL‐083298 (IL,RM,MC,PVS), and R00 HL‐103789 (YF); AHA MWA Pre‐doctoral Fellow 14PRE20490156 (EL) and the Chicago Biomedical Consortium with support from the Searle Funds at the Chicago Community Trust (DE).

Aortic Atherosclerosis Determines Increased Retrograde Blood Flow as a Potential Mechanism of Retrograde Embolic Stroke

Background: Retrograde brain embolization from complex plaques of the proximal descending aorta (DAo) has been identified as a new potential mechanism of stroke. Our purpose was to identify predictors of increased retrograde aortic blood flow indicating an elevated risk of brain embolization from the DAo. Methods: A total of 485 patients with acute ischemic stroke were prospectively included and underwent transesophageal echocardiography. Blood flow velocities in the proximal DAo were studied using 2D pulse-wave Doppler ultrasound. Velocity-time integrals (VTI) were calculated for antegrade and retrograde velocity directions. The ratio (VTI_retrograde/VTI_antegrade) was used to estimate retrograde flow extent. Associations between patient demographics, cardiovascular risk factors, echocardiographic parameters, and VTI_ratio were analyzed using multivariate linear regression. Results: Retrograde blood flow in the DAo occurred in all patients. Velocity profiles in the proximal DAo were as follows (mean ± SD): VTI_antegrade = 21.1 ± 6.5, VTI_retrograde = 11.0 ± 3.6, and VTI_ratio = 0.54 ± 0.16. Diameter (r = 0.25, p < 0.001), presence of complex plaques (r = 0.12, p = 0.007), and reduced strain of the DAo (r = -0.23, p < 0.001) had significant partial effects in a predictor model based on predefined variables, which predicted 26% (adjusted R² = 0.26) of the variance in VTI_ratio. A unit increase in the DAo diameter was associated with a 2% increase in VTI_ratio (95% CI 1-2.8%, p < 0.001). Presence of complex plaques increased VTI_ratio by 7% (95% CI 2-13%, p = 0.007) and an increase in strain by 0.1 indicated a decrease in VTI_ratio by about 11% (95% CI 6.2-15.5%, p < 0.001). Complex atheroma was found in the proximal DAo of 79 subjects, of which 40 (50.6%) had a VTI_ratio above average (VTI_ratio ≥0.54) compared to 87 of 261 (33.3%) patients without any complex plaques (p < 0.001). Twenty-five of 79 (31.7%) patients with complex DAo plaques had a VTI_ratio ≥0.60, which indicates a high likelihood of retrograde pathline length of ≥3 cm and thus increased risk of retrograde cerebral embolization. Stroke etiology of those 25 patients was determined in 13 and cryptogenic in 12 cases. Conclusions: Retrograde blood flow in the DAo was found in all stroke patients. However, it increased further in patients with concomitant complex plaques, low strain, and/or large aortic diameter, that is, in those with atherosclerosis of the DAo. Accordingly, such patients may be predisposed to retrograde embolization in case of occurrence of a complex plaque in proximity to a brain-supplying artery.

Effects of Valsalva Maneuver by Different Breath-holding Techniques to Detect Pulmonary Thromboembolism in a Contrast-enhanced Computed Tomography Examination.

The purpose of this study is to measure the hemodynamics on the effect of Valsalva maneuver aiming at pulmonary thromboembolism (PTE) using 2-dimensional (2D) phase contrast imaging of magnetic resonance image (MRI), Philips Ingenia 3.0-tesla (T). The maximal inspiration reduced the blood flow rate in various degrees at all measurement positions, superior vena cava (SVC), inferior vena cava (IVC), pulmonary artery (PA), ascending aorta (AA), and descending aorta (DA). This result suggests that the contrast effect in the PA might become weak during general PA phase to give a substantial influence of Valsalva maneuver in the condition after maximum inspiration. A contrast-enhanced computed tomography (CT) examination aiming at detection for PTE should be scanned without an advance maximum inspiration.

Longitudinal Evaluation of Aortic Hemodynamics in Marfan Syndrome: New Insights from a 4D Flow Cardiovascular Magnetic Resonance Multi-Year Follow-Up Study

BackgroundThe aim of this 4D flow cardiovascular magnetic resonance (CMR) follow-up study was to investigate longitudinal changes in aortic hemodynamics in adolescent patients with Marfan syndrome (MFS).Methods4D flow CMR for the assessment of in-vivo 3D blood flow with full coverage of the thoracic aorta was performed twice (baseline scan t1/follow-up scan t2) in 19 adolescent MFS patients (age at t1: 12.7 ± 3.6 years, t2: 16.2 ± 4.3 years) with a mean follow-up duration of 3.5 ± 1.2 years. Ten healthy volunteers (24 ± 3.8 years) served as a control group. Data analysis included aortic blood flow visualization by color-coded 3D pathlines, and grading of flow patterns (helices/vortices) on a 3-point scale (none, moderate, severe; blinded reading, 2 observers). Regional aortic peak systolic velocities and systolic 3D wall shear stress (WSS) along the entire aortic wall were quantified. Z-Scores of the aortic root and proximal descending aorta (DAo) were assessed.ResultsRegional systolic WSS was stable over the follow-up duration, except for a significant decrease in the proximal inner DAo segment (p = 0.02) between t1 and t2. MFS patients revealed significant lower mean systolic WSS in the proximal inner DAo compared with volunteers (0.78 ± 0.15 N/m2) at baseline t1 (0.60 ± 0.18 N/m2; p = 0.01) and follow-up t2 (0.55 ± 0.16 N/m2; p = 0.001). There were significant relationships (p < 0.01) between the segmental WSS in the proximal inner DAo, DAo Z-scores (r = −0.64) and helix/vortex pattern grading (r = −0.55) at both t1 and t2. The interobserver agreement for secondary flow patterns assessment was excellent (Cohen’s k = 0.71).ConclusionsMFS patients have lower segmental WSS in the inner proximal DAo segment which correlates with increased localized aberrant vortex/helix flow patterns and an enlarged diameter at one of the most critical sites for aortic dissection. General aortic hemodynamics are stable but these subtle localized DAo changes are already present at young age and tend to be more pronounced in the course of time.