Aneurysm Volume Research Articles

Correlation between gray matter volume loss followed by aneurysmal subarachnoid hemorrhage and subarachnoid hemorrhage volume

Aneurysmal subarachnoid hemorrhage (SAH) can chronically affect cognitive function, and SAH has been suggested to result in regional brain damage. This study aimed to assess regional structural damage according to initial clinical status including SAH volume. A total of 63 consecutive patients treated with coil embolization for intracranial aneurysms for more than 6months were enrolled. Of these, 35 patients had SAH and 28 patients who were treated for unruptured aneurysms served as controls. Volumetric T1-weighted images were acquired with 1mm isotropic voxel. The SAH volume was measured semi-automatically from the initial brain CT scan. Voxel-based group comparison was conducted to assess regional gray matter volume (GMV) changes. Voxel-based multiple regression was conducted to analyze regional GMV change and SAH volume. The clinical factors (Glasgow Coma Scale (GCS), SAH volume, systolic blood pressure, and serum laboratory findings) associated with regional GMV were also analyzed by using multiple regression. The SAH group had significantly lower GMV in the left hippocampus and higher GMV in the visual cortex than controls (Alphasim-corrected p < 0.05, voxel level of p < 0.001). The GMV of the bilateral hippocampi, thalami, and left medial orbital gyrus was negatively correlated with the initial SAH volume (FDR-corrected p < 0.05). SAH volume and GCS were associated with the hippocampal GMV in multiple regression (p < 0.05). Chronic regional GMV change after SAH was related to the severity of initial clinical status including SAH volume. This finding supports the pathophysiological hypothesis of SAH-induced microstructural brain injury.

Time-Enhancement Curve of Four-Dimensional Computed Tomography Predicts Aneurysm Enlargement with Type-II Endoleak after Endovascular Aneurysm Repair.

Objective We investigated the hemodynamic features of Type-II endoleaks after endovascular aneurysm repair (EVAR) using four-dimensional (4D) computed tomography (CT) to identify patients with aneurysm enlargement. Methods During a 13-month period (January 2017–January 2018) at our institution, we performed 4D-CT examinations in 13 patients after EVAR because of suspected Type-II endoleaks. Three patients were excluded from the study because of other endoleaks or absence of detectable endoleaks. The ramaining 10 patients were divided into two groups: enlargement group ( n = 4), in which the aneurysm volume increased, and stable group ( n = 6), in which the aneurysm remained stable or shrank. A CT scanner and three-dimensional workstation were used. All images were obtained using a consistent protocol (22 phase scans using the test bolus tracking method). We analyzed the hemodynamics of the endoleak cavity (EC) relative to those of the aorta and evaluated the time-enhancement curves (TECs) using measurement protocols. The strengths of correlations between these factors in the two groups were analyzed statistically. Results TECs in the enlargement group showed a more gradual curve, and the upslope, the gradient of TEC in the ascending phase and the upslope index were significantly more gradual than those in the stable group ( p = 0.0247, 0.0243). The EC washout and the EC washout index were also more gradual than in the stable group's ( p = 0.019, 0.019). The enhancement duration was longer in the former than in the latter (80%, p = 0.0195; 70%, p = 0.0159; 60%, p = 0.0159). The CT number in the equilibrium phase was larger in the enlargement group than in the stable group ( p = 0.019). Conclusion The 4D-CT is useful for predicting aneurysm enlargement with Type-II endoleaks after EVAR.

Combining Volumetric and Wall Shear Stress Analysis from CT to Assess Risk of Abdominal Aortic Aneurysm Progression.

Background Despite known limitations, the decision to operate on abdominal aortic aneurysm (AAA) is primarily on the basis of measurement of maximal aneurysm diameter. Purpose To identify volumetric and computational fluid dynamics parameters to predict AAAs that are likely to progress in size. Materials and Methods This study, part of a multicenter prospective registry (NCT01599533), included 126 patients with AAA. Patients were sorted into stable (≤10-mL increase in aneurysm volume) and progression (>10-mL increase in aneurysm volume) groups. Initial AAA characteristics of the derivation cohort were analyzed (maximal diameter and surface, thrombus and lumen volumes, maximal wall pressure, and wall shear stress [WSS]) to identify relevant parameters for a logistic regression model. Model and maximal diameter diagnostic performances were assessed in both cohorts and for AAAs smaller than 50 mm by using area under the receiver operating characteristic curve (AUC). Results Eighty-one patients were included (mean age, 73 years ± 7 years [standard deviation]; 78 men). The derivation and validation cohorts included, respectively, 50 and 31 participants. In the derivation cohort, there was higher mean lumen volume and lower mean WSS in the progression group compared with the stable group (60 mL ± 14 vs 46 mL ± 18 [P = .005] and 66% ± 6 vs 53% ± 9 [P = .02], respectively). Mean lumen volume and mean WSS at baseline were correlated to total volume growth (r = 0.47 [P = .002] and -0.42 [P = .006], respectively). In the derivation cohort, a regression model including lumen volume and WSS to predict aneurysm enlargement was superior to maximal diameter alone (AUC, 0.78 vs 0.52, respectively; P = .003); although no difference was found in the validation cohort (AUC, 0.79 vs 0.71, respectively; P = .51). For AAAs smaller than 50 mm, a regression model that included both baseline WSS and lumen volume performed better than maximal diameter (AUC, 0.79 vs 0.53, respectively; P = .01). Conclusion Combined analysis of lumen volume and wall shear stress was associated with enlargement of abdominal aortic aneurysms at 1 year, particularly in aneurysms smaller than 50 mm in diameter. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Mitsouras and Leach in this issue.

Geometrical Evaluation of Aortic Sac Remodeling During Two-Step Thoracoabdominal Aortic Aneurysm Endovascular Repair

The present study evaluates aneurysmal sac remodeling and the loss of the intercostal arteries after the first step of staged treatment of thoracoabdominal aortic aneurysms (TAAAs). The purpose of this approach is to keep the aneurysmal sac temporarily perfused to induce progressive thrombosis of the aneurysm while simultaneously allowing the spinal cord to establish adequate perfusion thereby promoting the development of collateral circulation. All patients with type II or type III TAAAs, having undergone 2-step endovascular treatment with at least a 2-branch endoprosthesis at our institution between April 2017 and May 2019, were retrospectively evaluated. Thirty-day mortality and spinal cord ischemia was assessed. The mean number of the intercostal and lumbar arteries, coverage length between the left subclavian artery and the stent graft proximal landing zone, total volume of the aneurysmal sac, lumen volume, and thrombosis volume were measured by preoperative and first-step postoperative computed tomography angiography. Patients were also grouped based on the chosen endoprosthesis (group A: double-branch aneurysmal sac reperfusion; group B: single-branch aneurysmal sac reperfusion). Eleven patients (mean age: 76.5 years; range: 61-86) were considered. No 30-day mortality was observed after the first-step procedure, and 1 patient died after second-step treatment. No permanent paraplegia was observed after either the first or second endovascular steps. The lumen volume significantly decreased (27%; P<0.001) after first-step endovascular treatment although there was a significant increase in aneurysm thrombosis (34% to 54%). The mean number of the intercostal arteries decreased from 19.7 to 9.3 (P<0.001) after first-step endovascular treatment. Volume variations and percentage of intercostal loss did not significantly differ between the 2 groups. Although aneurysm volume continued to increase after first-step treatment, two-step endovascular treatment is a feasible alternative to reduce the risk of severe ischemia in patients with extended TAAAs.

Experience in the treatment of patients with fusiform aneurysms of cerebral vessels

Experience in the treatment of patients with fusiform aneurysms of cerebral vessels

Relationship between Aneurysm Volumetric Changes and Endoleaks after Endovascular Abdominal Aortic Aneurysm Repair

Objective To evaluate the relationship of volumetric changes and endoleaks after endovascular aneurysm repair(EVAR)for abdominal aortic aneurysms(AAAs). Methods We retrospectively evaluated the clinical and imaging data of 54 patients who had underwent EVAR within 1 month after their aneurysms were detected.All patients received abdominal and pelvic enhanced computed tomography(CTA)for two follow-up visits in Peking Union Medical College Hospital from July 2014 to February 2019.Three-dimensional volumes and maximum diameters on axial CT of the aortic aneurysms were calculated by dedicated semi-automated 3D segmentation software before surgery(V0 and D0),in the 4 th postoperative month(V1and D1),and in the 12 th postoperative month(V2and D2),respectively.The presence or absence of endoleak for each patient with the V1/V0,V2/V0,and V2/V1 were calculated to assess the significance of volume changes with respect to endoleaks and the correlation between volume changes and maximum diameter changes on axial CT images. Results Of the 54 patients,endoleaks were found in 11 patients at the first follow-up visit(4 months after surgery),among whom 8 patients were arranged a second follow-up visit(12 months after surgery),during which endoleaks were found in 5 patients.Fifteen of 43 non-leaked patients underwent a second CTA examination,which revealed endoleak in one case.Patients who did exhibit endoleaks[n =11,V1/V0=1.086(1.033,1.116)]showed significant increases in aneurysm volume when compared with those who did not exhbit endoleaks[n =43,V1/V0=1.019(0.970,1.065)]at the first follow-up visit(Z=-2.695,P=0.007),although no significant difference was found with regard to volume changes between endoleaks(n=6,V2/V0=1.1±0.2,V2/V1=1.0±0.1)and non-endoleaks(n=17,V2/V0=1.0±0.1,V2/V1=1.0±0.1)at the second follow-up visit(t=0.725,P=0.476)as well as between these two follow-up visits(t=-0.021,P=0.984).V0 and D0 were moderately correlated with V1 and D1,respectively(r=0.5,P<0.001)and strongly correlated with V2 and D2,respectively(r=0.8,P<0.001).V1 and D1 were strongly correlated with V2 and D2,respectively(r=0.8,P<0.001). Conclusions The changes of aneurysm volume cannot reliably reflect the occurrence of endoleaks.The change of maximum axial diameter of aneurysm has certain correlation with the changes of aneurysm volume.

Assessing the Risk of Intracranial Aneurysm Rupture Using Morphological and Hemodynamic Biomarkers Evaluated from Magnetic Resonance Fluid Dynamics and Computational Fluid Dynamics.

Purpose:Evaluate in vivo hemodynamic and morphological biomarkers of intracranial aneurysms, using magnetic resonance fluid dynamics (MRFD) and MR-based patient specific computational fluid dynamics (CFD) in order to assess the risk of rupture.Methods:Forty-eight intracranial aneurysms (10 ruptured, 38 unruptured) were scrutinized for six morphological and 10 hemodynamic biomarkers. Morphological biomarkers were calculated based on 3D time-of-flight magnetic resonance angiography (3D TOF MRA) in MRFD analysis. Hemodynamic biomarkers were assessed using both MRFD and CFD analyses. MRFD was performed using 3D TOF MRA and 3D cine phase-contrast magnetic resonance imaging (3D cine PC MRI). CFD was performed utilizing patient specific inflow–outflow boundary conditions derived from 3D cine PC MRI. Univariate analysis was carried out to identify statistically significant biomarkers for aneurysm rupture and receiver operating characteristic (ROC) analysis was performed for the significant biomarkers. Binary logistic regression was performed to identify independent predictive biomarkers.Results:Morphological biomarker analysis revealed that aneurysm size [P = 0.021], volume [P = 0.035] and size ratio [P = 0.039] were statistically significantly different between the two groups. In hemodynamic biomarker analysis, MRFD results indicated that ruptured aneurysms had higher oscillatory shear index (OSI) [OSI.max, P = 0.037] and higher relative residence time (RRT) [RRT.ave, P = 0.035] compared with unruptured aneurysms. Correspondingly CFD analysis demonstrated significant differences for both average and maximum OSI [OSI.ave, P = 0.008; OSI.max, P = 0.01] and maximum RRT [RRT.max, P = 0.045]. ROC analysis revealed AUC values greater than 0.7 for all significant biomarkers. Aneurysm volume [AUC, 0.718; 95% CI, 0.491–0.946] and average OSI obtained from CFD [AUC, 0.774; 95% CI, 0.586–0.961] were retained in the respective logistic regression models.Conclusion:Both morphological and hemodynamic biomarkers have significant influence on intracranial aneurysm rupture. Aneurysm size, volume, size ratio, OSI and RRT could be potential biomarkers to assess aneurysm rupture risk.

Machine deep learning accurately detects endoleak after endovascular abdominal aortic aneurysm repair

ObjectiveThe objective of this study was to develop a machine deep learning algorithm for endoleak detection and measurement of aneurysm diameter, area, and volume from computed tomography angiography (CTA). MethodsDigital Imaging and Communications in Medicine files representing three-phase postoperative CTA images (N = 334) of 191 unique patients undergoing endovascular aneurysm repair for infrarenal abdominal aortic aneurysm (AAA) with a variety of commercial devices were used to train a deep learning pipeline across four tasks. The RetinaNet object-detection convolutional neural network (CNN) architecture was trained to predict bounding boxes around the axial CTA slices that were then stitched together in two dimensions into a smaller region containing the aneurysm. Multiclass endoleak detection and segmentation of the AAA, endograft, and endoleak were performed on this smaller region. Segmentations on a single randomly selected contrast from each scan included 33 full and 68 partial segmentations for endograft and AAA and 99 full segmentations for endoleak. A modified version of ResNet-50 CNN was used to detect endoleak on individual axial slices. A three-dimensional U-Net CNN model was trained on the task of dense three-dimensional segmentation and used to measure diameter and volume with a specially designed loss function. We made use of fivefold cross-validation to evaluate model performance for each step, splitting training and testing data at each fold, such that multiple scans from the same patient were preserved with the same fold. Algorithm predictions for endoleak were compared with the radiology report and with a subset of CTA images independently read by two vascular specialists. ResultsThe localization portion of the network accurately predicted a region of interest containing the AAA in 99% of cases. The best model of binary endoleak detection obtained an area under the receiver operating characteristic curve of 0.94 ± 0.03 with an optimized accuracy of 0.89 ± 0.03 on a balanced data set. An introduced postprocessing algorithm for determining maximum diameter was used on both the predicted AAA segmentation and ground truth segmentation, predicting on average an absolute diameter error of 2.3 ± 2.0 mm by 1.4 ± 1.7 mm for each measurement, respectively. The algorithm measured AAA and endograft volume accurately (Dice coefficient, 0.95 ± 0.2) with an absolute volume error of 10.1 ± 9.1 mL. The algorithm measured endoleak volume less accurately, with a Dice score of 0.53 ± 0.21 and an average absolute volume error of 1.2 ± 1.9 mL. ConclusionsThis machine learning algorithm shows promise in augmenting a human's ability to interpret postoperative CTA images and may help improve surveillance after endovascular aneurysm repair. External validation on larger data sets and prospective study are required before the algorithm can be clinically applicable.

Endocan expression correlated with total volume of coronary artery dilation in patients with coronary artery ectasia.

IntroductionInflammation and angiogenesis disturbances are considered as factors contributing to the development of coronary artery ectasias (CAE). Endocan (endothelial cell-specific molecule-1 – ESM-1) regulates both inflammatory and angiogenetic processes. However, there are no data about the correlation between endocan level and the severity of CAE measured with total volume of coronary artery dilation.AimTo assess whether the severity of the inflammatory process measured as endocan concentration correlates with the total volume of CAE.Material and methodsWe selected prospectively a total of 43 consecutive patients with coronary artery ectasia from 2240 patients who underwent coronary angiography in our center. Determination of endocan was performed by using the Human Endothelial cell-specific Molecule 1 (ECSM1/ENDOCAN) ELISA Kit. 3D QCA (three-dimensional quantitative coronary angiography) was used for coronary lesion and aneurysm quantification. The total volume of dilation was defined as the volume of all aneurysms and ectasias of coronary arteries in 1 patient.ResultsThe mean volume of all aneurysms in 1 patient was 677 ±878.7 mm3. The total aneurysm volume was positively strongly correlated with endocan concentration (Pearson correlation coefficient: 0.811; 2-tailed p < 0.001).ConclusionsEndocan is a potential marker of vascular wall damage mainly as a result of inflammation in the course of atherosclerosis, but also vascular remodeling as a result of a disturbance of pro- and anti-angiogenic processes. Endocan level reflects the intensity of the above processes and therefore correlates with the severity of CAE, measured as the total volume of dilation.

Aneurysm Sac Thrombus Volume Predicts Aneurysm Expansion with Type II Endoleak After Endovascular Aneurysm Repair

Several studies have analyzed risk factors that may influence the incidence of type II endoleak with sac expansion after endovascular aneurysm repair (EVAR). However, the impact of intraluminal thrombus volume on the incidence of sac expansion with type II endoleak requires further analysis. This study examined the correlation between preoperative intraluminal thrombus and the incidence of type II endoleak and late sac expansion by measuring the thrombus volume. Between June 2007 and March 2014, 423 patients underwent EVAR at our institution. Two hundred and eighty patients with preoperative and postoperative computed tomography angiography (CTA) were included in this study. Data were collected prospectively and supplemented with a retrospective review of the medical records and radiologic images, and demographic and clinical characteristic profiles were collected. Logistic regression and Cox regression analyses were used to assess each variable's association with the incidences of persistent or new endoleak and sac expansion. Of the 280 patients, 46.7% (131 patients) had persistent type II endoleak, and 19.6% (55 patients) had persistent type II endoleak with significant sac expansion (≥5mm). The mean follow-up duration was 60months (interquartile range, 24-72months). Cox regression analysis showed that older age (P=0.001), intraluminal thrombus volume ratio (thrombus volume [T vol]/aortic aneurysm volume [A vol]) (P=0.042) and IMA diameter (P=0.004) were significant predictors of the incidence of sac expansion with persistent or new type II endoleak. The receiver operating characteristic curve analysis revealed a cutoff of 51% T vol/A vol (area under the curve [AUC]: 0.59) and 2.9mm (area under the curve [AUC]: 0.60). The rate of freedom from sac expansion (≥5mm) during followup was significantly higher in patients with ≥51% T vol/A vol than in those with a lower T vol/A vol (P=0.010). Preoperative sac thrombus volume, IMA diameter, and older age predict the incidence of aneurysm expansion with type II endoleak after EVAR.

Factors Associated With Lower Incidence of Rupture in Abdominal Aortic Aneurysms

Introduction: The only current standard in international guidelines for estimating rupture risk of an abdominal aortic aneurysm (AAA) is the maximum diameter. The aim of this study was to evaluate anatomical factors in large (>80mm) AAA, in which the impact of diameter on rupture incidence is similar and profound, that may be associated with lower incidence of rupture. Methods: This was a retrospective study including patients with large (>80mm) aneurysms. Total of 62 patients were included in the study; matched 1:1 for age, and smoking (31 elective; 92±9.7mm vs. 31 ruptures; 95.7±12mm; p=0.5). Pre-operative computed tomography angiography was analyzed with a dedicated workstation and AAA anatomical characteristics were compared. The prognostic utility of several factors on rupture occurrence was also examined with receiver operating characteristic (ROC) curves. Results: Significantly different anatomical characteristics between elective vs ruptures were infra-renal aortic neck diameter at 5mm, 10mm and 15mm, neck length and calcification, common iliac length (CIA), pelvic artery index, left CIA and external iliac artery, total and true lumen volume. Intraluminal thrombus (ILT) volume did not differ (elective vs. ruptures; 233cc vs 245cc, p=0.76), although its form did (elective vs. ruptures; no thrombus 0% vs 20%, p=0.025; circular thrombus 63.3% vs 44%, p=0.03, respectively). After multivariate analysis, shorter left CIA (OR 1.07, CI. 1.01- 1.1, p=0.016) and smaller total aneurysm volume (OR 1.007, CI. 1.001-1.014, p=0.016) were associated with intact AAA. After a ROC curve analysis, left CIA < 50mm demonstrated lower incidence of rupture with sensitivity 60% and specificity 78%, while for total aneurysm volume of < 380cc the sensitivity and the specificity was 60% and 60%, retrospectively. Conclusion: Anatomical characteristics other than maximum diameter AAAs seem to be associated with incidence of rupture. Lower total aneurysm volume, but not ILT volume, and shorter left CIA may be associated with lower incidence of AAA rupture, even in large diameter AAA. Disclosure: Nothing to disclose

Follow-Up on Small Abdominal Aortic Aneurysms Using Three-Dimensional Ultrasound: Volume Versus Diameter

Introduction - Rupture risk in abdominal aortic aneurysms (AAAs) is assessed from the AAA’s diameter (1-5); yet, every tenth rupture case occurs in a small aneurysm (1,6-9). This underlines the inadequacy of the diameter as a stand-alone parameter. In this prospective follow-up study, ultrasound determined aneurysm diameter was compared with aneurysm volume determined by three-dimensional ultrasound (3D-US) in a group of 179 AAA patients.

Spatial Distribution of Abdominal Aortic Aneurysm Surface Growth and Correlation with Diameter and Volume Expansion

Introduction - The management of Abdominal Aortic Aneurysms (AAAs) is currently based on maximum size and growth rate criteria. Large or rapidly growing AAAs are thought to be at an increased risk of rupture, thus being suitable for intervention. Size and growth are determined based on the maximum diameter alone. Nevertheless, this variable takes into account a single portion of the vessel, while expansion is non-uniform, characterized by significant spatial variability. We aim to quantify regional surface growth of a cohort of AAAs. Methods - This is a single institution study including 31 lesions. Each AAA should have at least one baseline and one follow-up CT scan. From those, 3-Dimensional AAA models were created by semi-automated segmentation using dedicated software. Maximum orthogonal diameter and total aneurysm volume were recorded and used to calculate annual growth rate. Regional surface growth was quantified using the VascForm algorithm, which is written in Matlab, adapted to aneurysm follow-up studies and has been recently validated.[1] In general it is based on non-rigid point cloud registration and the iterative closest point algorithm. Initially, surfaces are pre-aligned applying principal component analysis and a general deformation of the Source surface is performed in order to best match the Target. Then, the surfaces are finely matched through a non-rigid local deformation model and each point in the Source surface is placed closer to the Target surface. After the registration, the surface growth distribution is the discretized surface element growth distribution. Maximum and average surface growth were calculated and correlated with the diameter and volume growth rate. The Spearman rho correlation coefficients were calculated and the statistical significance was tested using a two-tailed test. In order to identify potential correlation between intraluminal thrombus deposition (ILT) and surface growth, the co-localization of maximum surface growth with initial ILT maximum thickness was examined. Results - Median annual surface growth was 6.7%(0%>68%) and maximum surface growth was 26%(12%>444%). Correlations between surface and diameter/volume growth are summarized in Table 1. In 48% of follow-ups (15/31), maximum surface growth occurred away from the site of maximum diameter and thus could not have been captured by the measurement of maximum diameter growth. Sixteen cases presented maximum surface growth away and fifteen at the region of maximum initial ILT thickness. AAAs in the former group had significantly lower initial ILT thickness (11.3 vs 19.5mm, p<0.001) compared to those in the latter.Tabled 1DmaxVolumeMaxSurfaceCorrelationCoefficient,465,544Sig. (2-tailed),014,009AvgSurfaceCorrelationCoefficient,389,866Sig. (2-tailed),045,000 Open table in a new tab Conclusion - Regional surface growth of AAAs is not uniform. Average and maximum surface growth are related to the diameter growth but the correlation is only moderate. Volume growth presents very strong correlation with average but only moderate correlation with maximum surface growth rate. Almost half of the lesions display maximum surface growth at a site different from that of maximum diameter. Regional growth is related to initial local amount of ILT. Surface growth provides a means to evaluate spatial distribution of AAA expansion which may be of value for rupture risk predictions. References Metaxa E, Iordanov I, Maravelakis E, Papaharilaou Y. A novel approach for local abdominal aortic aneurysm growth quantification. Medical & Biological Engineering. DOI 10.1007/s11517-016-1592-8.

Anatomical Differences Between Intact and Ruptured Large Abdominal Aortic Aneurysms

Purpose: To compare different anatomical characteristics between intact and ruptured large abdominal aortic aneurysms (rAAA >80 mm) with the goal of refining the process of estimating rupture risk. Materials and Methods: A retrospective study involving 62 male patients with large (>80 mm) aneurysms matched for age and smoking produced a 31-patient elective group with a mean maximum aneurysm diameter of 92±9.7 mm and a 31-patient rAAA group (mean maximum aneurysm diameter 95.7±12 mm). Preoperative computed tomography angiography scans were analyzed with a dedicated workstation, and anatomical characteristics of the aortic neck, iliac arteries, and aneurysm were compared in multivariable regression analyses; the outcomes are given as the odds ratio (OR) with 95% confidence interval (CI). The prognostic utility of several characteristics as predictors of rupture occurrence was examined with receiver operating characteristic (ROC) curves. Results: Anatomical characteristics differing significantly between elective and ruptured aneurysms were the infrarenal aortic neck diameters at 5 mm, 10 mm and 15 mm; the neck length and calcification; the common iliac artery (CIA) lengths; the iliac artery indexes; the left CIA and external iliac artery diameters; and the total and true lumen aneurysm volumes. Intraluminal thrombus (ILT) volume did not differ (p=0.76), although its distribution in elective vs ruptured cases did [absent: 0% vs 19%, respectively (p=0.025); circumferential: 61% vs 35%, respectively (p=0.04)]. Total aneurysm volume was higher in rAAA (442±140 mL) vs intact AAA (331±143 mL, p=0.014), while the ILT/total aneurysm volume rate was lower in rAAA (55%) vs intact AAA (70%, p=0.02). Multivariate analysis determined that a shorter left CIA (OR 1.07, 95% CI 1.01 to 1.1, p=0.016) and a smaller total aneurysm volume (OR 1.007, CI. 1.001 to 1.014, p=0.016) were associated with intact AAA. After a ROC curve analysis, left CIA length <50 mm demonstrated a lower incidence of rupture (sensitivity 60% and specificity 78%), while total aneurysm volume <380 mL had 60% sensitivity and specificity. Conclusion: Large rAAAs seem to have different anatomical characteristics than similarly sized intact AAAs. Large intact AAAs have lower total aneurysm volumes and shorter left CIAs, with higher ILT/aneurysm volume rates.

Volume variation may be a relevant metric in the study of aneurysm pulsatility: a study using ECG-gated 4D-CTA (PULSAN)

​Background and purposeIntracranial aneurysms are a frequently occurring disease, with an estimated prevalence of 2–5% in the general population. They usually remain silent until rupture occurs, with a mortality rate...

NHS hospital readiness to embrace the proposed NICE guidelines on abdominal aortic aneurysm: a public perspective.

The National Institute for Health and Care Excellence published a draft consultation update on abdominal aortic aneurysm, which was expected to be published on 7 November 2018. This article analyses the readiness of NHS hospitals and their workforce to embrace the proposed guidelines. The trust and individual surgeon-level anonymised data in the public domain for elective, rupture and complex abdominal aortic aneurysm cases were collected and analysed for all the acute care trusts providing these services from the Vascular Society of Great Briton and Ireland's prospective National Vascular Registry database. Of the 95 acute care trusts providing the service for the year 2017, the annual volume of infrarenal abdominal aortic aneurysm (both endovascular and open repairs) ranged between 0 and 137. Of these, 64 (67.36%) trusts had an annual volume of fewer than 60 cases. A total of 366 (approximately 75% of 490) vascular surgeons have performed 10 or fewer open abdominal aortic aneurysm repairs in three years (2014-2016) with a mean operating volume of 1.452 procedures per surgeon per three years (n = 254, median 0, interquartile range, IQR, 0-3, 0.484 procedures per surgeon per year) and about 51% of the vascular surgeons have only performed five or fewer procedures in those three years with a mean operating volume of 3.455 per surgeon per three years (n = 367, median 3, IQR 0-3, 1.151 per surgeon per year). The observations show that most UK acute hospitals lack the optimum case volume necessary to embrace the proposed change in the guideline.

Allogeneic Mesenchymal Stem Cells Induce Regulatory T Cells and Suppress Aneurysm Inflammation: Interim Results of the Phase 1 ARREST Trial

We have previously shown that patients with abdominal aortic aneurysm (AAA) have decreased number and diminished immune suppressive function of regulatory type 1 T cells (Tr1) and increased numbers of activated effector Th17 cells. The objective of this clinical trial was to assess the efficacy of allogeneic mesenchymal stem cells (MSCs) in inducing Tr1 cells and suppressing AAA inflammation. The AneuRysm Repression with mEsenchymal STem cells (ARREST) trial is a blinded, placebo-controlled phase 1 study in which patients with small AAA (30- to 50-mm diameter) are randomized to intravenous infusion of placebo (plasmalyte A), 1 million MSCs/kg, and 3 million MSCs/kg (n = 12/group). Blood samples are collected at baseline and at days 3, 7, 14, 28, and 60 and yearly. The primary end point is change in the ratio of Tr1:Th17 cells at 14 days after treatment using flow cytometry. Secondary end points are changes in FoxP3+ T-regulatory cells, myeloid-derived suppressor cells, microRNA profiles, serum cytokine levels, changes in AAA inflammation as measured by 18-fluorodeoxyglucose positron emission tomography/computed tomography, and changes in aneurysm diameter and volume at years 1 to 5. Twenty-one patients have been enrolled to date. There have been no treatment-related adverse events, and one patient withdrew after discovery of an occult pulmonary malignant neoplasm on baseline positron emission tomography/computed tomography. At day 14, the ratio of Tr1:Th17 cells increased by 20.3 ± 1.3-fold from baseline for the high-dose MSC group (n = 7) compared with 4.3 ±-fold for the low-dose group (n = 7; P < .01) and −10 .6± 2.3-fold for the placebo group (n = 7; P = .001; Fig). There was a decrease in 18-fluorodeoxyglucose uptake as measured by standard uptake values by 5.6% ±1.3% in the combined MSC group (n = 7) compared with an increase in standard uptake values of 4.1% ± 1.0% in the placebo group (n = 4; P < .05). Although the sample size was too small for statistical comparison, the average increase in maximal transverse diameter of AAA at 12 months after treatment was −1.6 ± 0.6 mm in the combined MSC group (n = 4 ) and 4.3 ± 0.9 mm in the placebo group. The results of the ARREST trial demonstrate a significant increase in Tr1 cells concurrent with a decrease in cytotoxic effector Th17 cells in an MSC dose-dependent fashion, achieving the primary end point. Preliminary data suggest that aneurysm inflammation and expansion are decreased with MSC treatment.

Treatment Trends and Outcome of Aneurysmal Subarachnoid Hemorrhage by Hospital Volume

Abstract INTRODUCTION With increasing availability of endovascular aneurysm treatment, more patients with aneurysmal subarachnoid hemorrhage (SAH) may be treated at lower-volume centers. In this nationwide observational cohort study, we determine treatment trends over time and their impact on SAH patient outcome. METHODS Using data from the Nationwide Inpatient Sample (NIS, 2005-2015), we identified patients with aneurysmal SAH treated with either endovascular coiling (EC) or surgical clipping (SC). Patients with SAH from other causes, such as trauma or arteriovenous malformations, were excluded. Primary endpoint was in-hospital mortality and was assessed using multivariate logistic regression adjusted for age, comorbidities, and annual hospital SAH volume. Lower volume centers were defined as centers performing 10 or fewer annual SAH treatments. RESULTS Among 105 557 patients with aneurysmal SAH from 2005 to 2015, 68% were female and the median age was 54 [IQR 46-64]. In total, 60% were treated with EC and 40% with SC. Over the time span of the study, the number of patients with SAH remained comparable (8798 vs 9833, 2005 vs 2015), and the number of hospitals treating SAH did not increase. Lower-volume hospitals were more likely to perform SC early in the cohort (32% EC vs 68% SC, 2005-2011) compared to later (72% EC vs 28% SC, 2012-2015). In adjusted logistic regression from data between years 2012 and 2015, we observed a continuous decline in the likelihood of in-hospital mortality with increasing annual SAH treatments, with a significant decrease among hospitals performing 12 or more cases per year (OR 0.74, CI 0.58-0.93, P &lt; .05). CONCLUSION In this observational cohort, we found increasing numbers of patients treated with EC at lower volume centers over time. Increasing annual aneurysmal SAH treatment volume corresponded with decreasing in-hospital mortality.

Determination of Aneurysm Volume Critical for Stability After Coil Embolization: A Retrospective Study of 3530 Aneurysms

Recurrence is one of the concerns even after successful endovascular treatment of intracranial aneurysms. We sought to determine the critical aneurysm volume and risk factors related to aneurysmal stability in patients undergoing coil embolization of intracranial aneurysms. Aneurysm volume and follow-up imaging data were retrieved in 3042 patients with 3530 aneurysms who were treated with endovascular coil embolization from January 2006 to October 2016. We analyzed the anatomic outcome in relation to aneurysm volume and determined the critical aneurysm volume favoring coil embolization. Recanalization rates were 2.8%, 6.3%, 19.4%, and 67.4% in each group with aneurysm volume of <10, 10-100, 100-1000, and >1000 mm3, respectively. When we investigated the 100-1000 mm3 group, the recanalization rate remarkably increased at 500 mm3 (16.4% vs. 57.5%, P<0.0001; odds ratio [OR], 6.968; 95% confidence interval [CI], 3.562-13.631). In the entire cohort, recanalization rates were significantly different between aneurysm volume of <500 and >500 mm3 (7.2% vs. 62.9%, respectively; P < 0.0001; OR, 21.848; 95% CI, 13.944-34.235). In aneurysm volumes of >500 mm3, the location was a significant prognostic factor for long-term stability (posterior circulation vs. anterior circulation; OR, 4.737; 95% CI, 1.275-17.602; P= 0.020). In our series of cerebral aneurysms treated with coil embolization, 500 mm3 was found to be the critical volume determining stability after coil embolization. Large volume aneurysms in the posterior circulation were especially prone to recanalization after coiling.

Giant intracranial aneurysms of the posterior circulation and their relation to the brainstem: analysis of risk factors for neurological deficits.

Giant posterior circulation aneurysms (GPCirAs) usually cause substantial mass effect on the brainstem, which may lead to neurological deficits. So far, there has been no systematic investigation of factors associated with such deficits in GPCirA. The authors aim to examine the risk factors for cranial nerve deficit (CND), motor deficit, and disability in patients with GPCirA. Using MR images obtained in 30 patients with unruptured GPCirA, the authors examined GPCirA volume, presence of hydrocephalus or partial thrombosis (PT) of the aneurysm, and the degree of brainstem displacement measured by the distance between the McRae line and the tip of the GPCirA (∆MT). They evaluated associations between these factors and neurological deficits. Thirty GPCirAs in 30 patients were included. The prevalence of CNDs was 50%. Patients with CNDs significantly differed from those without CNDs in terms of age (mean 51.0 years [SD 15.0 years] vs 69.0 years [SD 21.0 years], p = 0.01) and in ∆MT (median 50.7 mm [IQR 39.2-53.9 mm] vs 39.0 mm [IQR 32.3-45.9 mm], p = 0.02). The prevalence of motor deficits was 33.3%. Patients with motor deficits showed a larger ∆MT (median 50.5 mm [IQR 40.8-54.6 mm]) compared with those without (∆MT: median 39.1 mm [IQR 32.8-50.5 mm], p = 0.04). GPCirA volume was larger in patients with poor modified Rankin Scale (mRS) scores (median 14.9 cm3 [IQR 8.6-18.7 cm3]) than in those with mRS scores of 0-2 (median 6.8 cm3 [IQR 4.4-11.7 cm3], p = 0.03). After adjusting for patient age and the occurrence of hydrocephalus or PT, the authors found that higher degrees of disability were significantly associated with aneurysm volume (OR 1.13, 95% CI 1.0-1.3; p = 0.04), but not with ∆MT. The occurrence of CND or motor deficit was not associated with any of the examined variables. There was no correlation between GPCirA volume and ∆MT (rs = 0.01, p = 0.96). The prevalence of neurological deficits did not differ between GPCirA at the basilar apex, the basilar trunk, the vertebrobasilar junction, or the vertebral artery. In this study, the neurological condition of the patients was associated only with GPCirA volume and not with the degree of brainstem displacement, the occurrence of PT or hydrocephalus, or the exact location of the GPCirA. These findings highlight the clinical relevance of GPCirA volume and suggest that factors such as brainstem displacement or PT should play less of a role when finding arguments for or against treatment of GPCirA.Clinical trial registration no.: NCT02066493 (clinicaltrials.gov).