Stable Aneurysm Research Articles

A technique for creating an experimental type Ia endoleak model in the thoracic aorta of swine

This study aimed to create an animal model of type Ia endoleak that creates persistent problems after thoracic endovascular aortic repair. In six swine, thoracic aortic aneurysms were created using the harvested jugular vein. We created a type Ia endoleak using a composite stent-graft comprising the first stent-graft (reverse-tapered: thicker part, 16mm; thinner part, 10mm) and the second stent-graft (tapered: thicker part, 18-20mm; thinner part, 16mm). This double-component stent-graft was deployed in the abdominal aorta and then moved upward to the proximal entry site of the thoracic aneurysm using the inflated balloon for precise positioning. After the surgical procedure and on postoperative day 8, aortography was performed to detect residual endoleak, and then the swine were euthanized. A stable aneurysm (mean size of all aneurysms, 16.8 ± 1.72mm × 11.8 ± 2.32mm) and type Ia endoleak were successfully observed in all swine. A single stent-graft was sufficient in one of the six swine. A novel technique to create a type Ia endoleak model can be successfully developed in swine.

Utility of skull X-rays in identifying recurrence of coiled cerebral aneurysms.

ObjectiveA high rate of cerebral aneurysm recurrence following endovascular coiling has prompted the use of digital subtraction angiography (DSA) for interval follow-up. However, the utility of skull x-rays as an alternative screening method for aneurysm recurrence is unproperly characterized.MethodsRetrospective review of a prospective registry of ruptured and unruptured cerebral aneurysms. Anteroposterior and lateral skull x-rays were obtained immediately at the end of the procedure and at 6-month follow-up. Aneurysm recurrence was defined by comparing post-procedure and 6-month DSA imaging. A true positive was defined as a change in coil mass morphology on at least one projection with aneurysm recurrence on DSA, and a true negative defined as a stable coil mass on both projections and no recurrence on DSA. Receiver operating characteristic area under the curve (AUC) statistics was used to assess the performance of skull x-rays in identifying aneurysm recurrence.ResultsA total of 118 cerebral aneurysms were evaluated with DSA imaging and skull x-rays. A change in coil mass morphology on one projection of skull x-rays correctly detected all true recurrences with a sensitivity of 100% (95% confidence interval [CI], 91-100%). Skull x-rays failed to identify a stable aneurysm coil mass in 15 cases, with a specificity of 79% (68-88%). Skull x-rays performed with AUC 0.8958 (95% CI, 0.8490-0.9431) in identifying aneurysm recurrence.ConclusionsThe findings of our study suggest that skull x-rays may represent a low-cost, non-invasive screening tool to rule out aneurysm recurrence, which can potentially aid in decreasing the utilization of DSA in the follow-up of patients with coiled cerebral aneurysms.

Complex and continuous change in hypothetic risk of rupture of intracranial cerebral aneurysms – Bleb mandala –

BackgroundThis study of the intraoperative microscopic findings indicated complex behavior of aneurysmal bleb affects the rupture risk. MethodsA total of 300 consecutive relatively small (mean 6.2 mm) unruptured ICAs were clipped from July 2005 to January 2019. Microscopically identified blebs were divided into four types based on external appearances. Type A bleb was a thick-walled bleb. Type B bleb was a thin-walled reddish bleb. Type C bleb was a healing organized bleb. Type D was a hemosiderin-laden bleb. Type B and D blebs were considered to be risky blebs for rupture. ICAs with bleb(s) were further categorized into two types, stable aneurysms and unstable aneurysms with Type B and/or D bleb(s). The number and nature of the blebs were compared with the demographic data of the patients and radiological findings of the ICAs to evaluate possible predictors of the hypothetic rupture risk. ResultsAneurysms tended to enlarge as the number of blebs increased (p = 0.073). High risk Type B bleb had significantly larger number of blebs (p < 0.05). Healing Type C bleb was significantly more common in the group with two blebs than one bleb (p < 0.01). No significant differences were found between stable and unstable aneurysms in aneurysm multiplicity, size, and radiological bleb. ConclusionsAneurysm state continuously changes due to the dynamic change of bleb number and nature. Our data suggests the necessity of new repeatable vessel-wall imaging technology to select risky unstable ICAs for treatment.

Off the Shelf Fenestrated Stent Grafts: “Mind The Gap?”

Off the Shelf Fenestrated Stent Grafts: “Mind The Gap?”

Chapter 6 - Advanced vascular imaging techniques

This chapter outlines recent advances in imaging of disorders of the cervicocerebral vasculature that permit evaluation of the lumen, the vessel wall, and the patterns of blood flow within the vessel. Noninvasive MR techniques to evaluate the vessel lumen, such as noncontrast time-of-flight magnetic resonance angiography and contrast-enhanced magnetic resonance angiography (CEMRA) are routinely used in diagnosis, planning, and posttreatment follow-up. More recently, high-resolution vessel wall imaging MRI (VWMRI) has been developed, which provides additional information about the vessel wall or aneurysm wall. VWMRI wall signal and enhancement patterns may permit differentiation between vasculopathies and between stable and unstable unruptured aneurysms. In addition, the study of blood flow patterns using phase-contrast MRI (4D flow MRI) and image-based computational fluid dynamics has been used to characterize flow and wall shear stress within aneurysms, flow within arteriovenous malformations (AVMs) and pulsatile tinnitus. Digital subtraction angiography (DSA), however, remains the gold standard in the evaluation and treatment of neurovascular diseases. New adjunctive DSA techniques, such as 4D-DSA reconstruction and color flow analysis, are also covered. These new MRI and DSA techniques increase diagnostic accuracy, improve understanding of the pathophysiology and natural history of neurovascular disease, inform and guide treatment, and may provide risk stratification for patients being considered for therapy.

Analysis of hemodynamic changes from aneurysm inception to large sizes.

While previous studies have identified many risk factors for the progression and rupture of cerebral aneurysms, the changes in aneurysm flow characteristics during its evolution are not fully understood. This work analyzes the changes in the aneurysm hemodynamic environment from its initial development to later stages when the aneurysm has substantially enlarged. A total of 88 aneurysms at four locations were studied with image based computational fluid dynamics (CFD). Two synthetic sequences representing the aneurysm geometry at three earlier stages were generated by shrinking the aneurysm sac while keeping the neck fixed or shrinking the neck simultaneously. The flow conditions were then quantitatively compared between these two modes of evolution. As aneurysms enlarged, the inflow rate increased in growing neck sequences, but decreased in fixed neck sequences. The inflow jet became more concentrated in both sequences. The mean aneurysm flow velocity and wall shear stress decreased in both sequences, but they decreased faster in enlarging aneurysms if the neck was fixed. Additionally, the intra-aneurysmal flows became more complex and more unstable, wall shear stress distribution became more oscillatory, and the area under low wall shear stress increased for both sequences. The evolution of flow characteristics of aneurysms with fixed and growing necks are different. The observed trends suggest that fixed neck aneurysms may evolve towards a flow environment characteristic of stable aneurysms faster than aneurysms with growing necks, which could also evolve towards a more disfavorable environment.

Lack of durability after transarterial ethylene-vinyl alcohol copolymer-embolization of type II endoleak following endovascular abdominal aortic aneurysm repair.

Background: Type II endoleak (T2EL) after endovascular aortic repair is associated with AAA sac enlargements in up to 25%, reduction of attachment zones and rarely with aortic rupture. Indications for therapy and efficacy of interventions of T2EL are not clearly established. Transarterial embolization with application of ethylene-vinyl alcohol copolymer has been described with varying outcomes. Aim of this study is to evaluate durability of OnyxTM embolization (OE) in T2EL in a consecutive series at a single tertiary vascular center. Patients and methods: Demographic data, technical success, pre- and postoperative aneurysm growth, morbidity, mortality and reintervention rates during hospital stay as well as in follow up were recorded in patients treated with OE for T2EL between 01/2015 and 12/2017. The primary endpoint was defined as persistence or reoccurrence of T2EL (durability of OE). Results: In total 15 patients (78±6years, 13 men) were treated with OE because of sac enlargement (average growth of 12±8%, n=12), persistent bleeding after AAA rupture (n=2) or persistent T2EL with stable but large aneurysm diameter (n=1). Mean length of stay was 8±11 days. Technical success was 93.3% (n=14). Inhospital-morbidity was 26.7%, in-hospital- and 1-year-mortality rate were 6.6% (n=1) and 20.0% (n=3). T2EL persisted in 20.0% (n=3) despite of OE. Re-EL-II occurred after 40 (30-114) days in 33.3% (n=5). Reintervention rate was 13.3% (n=2, atday 48 and 319). Altogether clinical success with stable aneurysm diameter was achieved in 80.0% (n=12), but durable elimination of EL was only achieved in 46.7% of patients (n=7). Conclusions: OE is technically possible in more than 90% of patients but might be associated with severe complications. Durability of this treatment is low, since T2EL persist or reoccur in more than 50% of all patients. OE of T2EL should be reserved for few selected cases.

A CASE OF TYPE II MYOCARDIAL INFARCTION INDUCED BY SEVERE AORTIC STENOSIS

SESSION TITLE: Medical Student/Resident Cardiovascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Severe aortic stenosis is known to be associated with a multitude of complications including heart failure, pulmonary hypertension, arrhythmias, acute coronary syndrome, and sudden cardiac death. We present a case of acute coronary syndrome in the setting of severe aortic stenosis. CASE PRESENTATION: 81-year-old man with PMH of moderate aortic stenosis(AVA 1.1cm2, gradient 29mmHg), atrial fibrillation, ascending aortic aneurysm, presented with sudden onset of chest pain. On arrival, he was hypoxic and was in bradycardic with HR in ’30s. After receiving atropine, his HR improved to ’50s. EKG showed junctional escape rhythm at 43 bpm, with significant ST Elevation of up to 4 mm in leads 2,3, aVF, V3-6, occasional PVCs with R on T phenomenon. Subsequently, he became pulseless and developed torsades requiring defibrillation X2 along with brief CPR to achieve spontaneous circulation. Troponin was elevated at 64.6 which later peaked to >200. Emergent LHC was done which showed normal coronary arteries with no significant blockages. Temporary femoral transvenous pacemaker placed for presumed bradycardia mediated torsades. CTA showed a stable aortic aneurysm and ECHO showed progression of aortic stenosis severity. Cardiac MRI was done to rule out myocarditis and other infiltrative etiologies. Cardiac MRI showed patchy focal fibrosis and edema of basal inferior septum most consistent with focal myocarditis. The magnitude of the troponin elevation way higher when compared with the area of focal myocarditis indicating there could be another mechanism of myocardial injury. The likely hypothesis is that patient developed Torsades secondary to bradycardia in the setting of Type II MI induced by severe aortic stenosis. Subsequently patient underwent TAVR and single chamber defibrillator as secondary prevention to prevent sudden cardiac death. DISCUSSION: AS when severe can cause various structural and autoregulatory changes leading to impairment of coronary flow reserve and myocardial ischemia in the absence of significant coronary artery disease. Compensatory LVH in AS increases the myocardial oxygen demand and also causes extravascular compression of the coronary microcirculation increasing the resistance in the microvasculature leading to impairment of myocardial perfusion. Severe AS is associated with a high risk of sudden cardiac death. A potential mechanism of SCD is activation of ventricular baroreceptors resulting in paradoxical bradycardia, decreased contractility, and hypotension (Bezold-Jarisch reflex). Timely valvular repair is known to decrease the complications of severe AS. Recent trials like RECOVERY are showing promising results of early surgery in asymptomatic severe AS Patients CONCLUSIONS: Severe aortic stenosis can result in sudden cardiac death secondary decreased coronary flow reserve in the absence of significant coronary artery disease. Reference #1: Circulation. 2003;107:3121–3123 Why Angina in Aortic Stenosis With Normal Coronary Arteriograms? K. Lance Gould and Blase A. Carabello Reference #2: Cardiol Res Pract. 2010;2010:423465. Published 2010 Jul 20. doi:10.4061/2010/423465 A case of critical aortic stenosis masquerading as acute coronary syndrome. Wayangankar SA, Dasari TW, Lozano PM, Beckman KJ. Reference #3: Nat Rev Cardiol 15, 420–431 (2018). https://doi.org/10.1038/s41569-018-0011-2 Pathophysiological coronary and microcirculatory flow alterations in aortic stenosis.Michail, M., Davies, J.E., Cameron, J.D. et al. DISCLOSURES: No relevant relationships by Tahreem Ahmad, source=Web Response No relevant relationships by Waqas Ali, source=Web Response No relevant relationships by Tariq Hassan, source=Web Response No relevant relationships by Pranali Santhoshini Pachika, source=Web Response

Management of a giant aortic root aneurysm in a young patient with Marfan syndrome: a case report

IntroductionMarfan syndrome (MFS) is a common heritable connective tissue disease involving multiple organs. Even though the clinical manifestations of MFS can be various, aortic root aneurysm is estimated as one of the most serious complications. We herein describe an individualized treatment decision-making process for a 23-year-old male with MFS, suffering from a giant but stable aortic root aneurysm which is extremely rare at his age.CaseThe patient, a 23-year-old male with a family history of MFS, presented to our cardiovascular department because of progressive exertional chest distress, fatigue and occasional precordial pain. Physical examinations revealed 190.5 cm of height, high myopia, and a diastolic murmur at the aortic valve area. Laboratory examinations for systemic vasculitis and infectious diseases were negative. Transthoracic echocardiography and enhanced thoracic computed tomography (CT) scan revealed the existence of a giant aortic root aneurysm (125.1 mm in short-axis), severe aortic valve regurgitation, cardiac dilatation (LV; 99 mm in diastolic diameter) and a poor ejection fraction (EF; 18%). Considering the risk of rupture or dissection of the dilated aortic root, we performed Bentall procedure based on the results of multidisciplinary team discussion and intraoperative exploration. Postoperative thoracic CT scan revealed a normal sized reconstructed aortic root, and the patient was discharged uneventfully 7 days later.ConclusionIt is extremely rare to report such a giant aortic root aneurysm in a young patient. In the treatment decision-making process, the patient’s specific situation should be taken into consideration. A mechanical Bentall procedure seems to be an acceptable option for some selected cases.

Surgical treatment patterns and clinical outcomes of patients treated for expanding aneurysm sacs with type II endoleaks after endovascular aneurysm repair

ObjectivePersistent type II endoleaks (T2ELs) after endovascular aneurysm repair (EVAR) with sac growth have been associated with adverse events, including rupture. Whereas intervention in the presence of aneurysm growth has become an accepted treatment paradigm for T2ELs, the efficacy and clinical success of such interventions remain unclear. Therefore, we examined the treatment patterns and clinical outcomes of patients undergoing T2EL interventions after EVAR. MethodsWe performed a retrospective review of all patients treated for expanding aneurysm sacs with T2ELs after EVAR at an academic medical center between 2006 and 2017. The primary outcomes assessed were need for repeated intervention; intervention types; and achievement of clinical success, defined as stable aneurysm sac size on computed tomography angiography after treatment. ResultsFifty-six patients underwent 119 interventions, of which 107 (90%) were technically successful. The median time from EVAR to index T2EL procedure was 37 months (interquartile range, 17-56 months), and the median follow-up time from first T2EL procedure was 27 months (interquartile range, 10-51 months). The most common index procedure was transarterial lumbar embolization (64%), followed by transarterial inferior mesenteric artery (20%), transcaval (14%), and translumbar embolization (1.8%). Thirty-three (59%) patients required further procedures for persistent aneurysm sac expansion. For subsequent T2EL interventions, the most common endovascular procedure was transarterial lumbar embolization (21%), followed by transcaval (21%), translumbar (11%), and transarterial inferior mesenteric artery embolization (8.6%). Twelve patients (21%) were found to have loss of proximal or distal seal on subsequent imaging and required graft extensions to stabilize aneurysm sac size. Ten patients (18%) ultimately underwent graft explantation or sacotomy with oversewing of the endoleak source. Freedom from any endoleak-related reintervention was 57% at 1 year and 36% at 3 years. Freedom from open treatment was 93% at 1 year and 82% at 3 years. Of the 44 patients with ≥6-month follow-up, 39 (89%) achieved clinical success. However, only 11 patients (25%) achieved clinical success without any further reintervention, and 29 patients (66%) achieved clinical success without open treatment. ConclusionsDespite high technical success, endoleak recurrence after T2EL treatment is common, and multiple interventions are often needed to stabilize aneurysm sac size in patients diagnosed with T2EL-associated sac growth. Notably, one in five patients treated for T2ELs was discovered, on further evaluation, to have proximal or distal seal zone loss that necessitated repair to achieve sac stability. Thus, thorough assessment of all endoleak types should be performed in patients with T2ELs associated with sac growth before T2EL treatment to ensure appropriate care and to minimize ineffective interventions.

Prognostic Significance of Aneurysm Sac Shrinkage After Endovascular Aneurysm Repair

Purpose: To investigate whether patients who develop aneurysm sac shrinkage following endovascular aneurysm repair (EVAR) have better outcomes than patients with a stable or increased aneurysm sac. Materials and Methods: The Healthcare Databases Advanced Search interface developed by the National Institute for Health and Care Excellence was used to interrogate MEDLINE and EMBASE. Thesaurus headings were adapted accordingly. Case-control studies were identified comparing outcomes in patients demonstrating aneurysm sac shrinkage after EVAR with those of patients with a stable or expanded aneurysm sac. Pooled estimates of dichotomous outcome data were calculated using the odds ratio (OR) and 95% confidence interval (CI). Meta-analysis of time-to-event data was conducted using the inverse-variance method; the results are reported as a summary hazard ratio (HR) and 95% CI. Summary outcome estimates were calculated using random-effects models. Results: Eight studies were included in quantitative synthesis reporting a total of 17,096 patients (8518 patients with sac shrinkage and 8578 patients without sac shrinkage). The pooled incidence of sac shrinkage at 12 months was 48% (95% CI 40% to 56%). Patients with aneurysm sac shrinkage had a significantly lower hazard of death (HR 0.73, 95% CI 0.60 to 0.87), secondary interventions (HR 0.42, 95% CI 0.29 to 0.62), and late complications (HR 0.37, 95% CI 0.24 to 0.56) than patients with a stable or increased aneurysm sac. Furthermore, their odds of rupture were significantly lower than those in patients without shrinkage (OR 0.09, 95% CI 0.02 to 0.36). Conclusion: Sac regression is correlated to improved survival and a reduced rate of secondary interventions and EVAR-related complications. The prognostic significance of sac regression should be considered in surveillance strategies. Intensified surveillance should be applied in patients who fail to achieve sac regression following EVAR.

Modified Intravascular Interventional Operation of Balloon-Bound Elastase Induction Method to Establish Rabbit Aneurysm Model Using Cardiovascular Angiography

Objective: In this paper, we establish a simple, efficient and stable rabbit aneurysm model using modified intravascular interventional operation of balloon-bound elastase induction method. Methods: We selected 20 healthy adult New Zealand white rabbits. An aortic aneurysm model of rabbit right common carotid artery was established by modified intravascular interventional balloon-binding elastase induction method using cardiovascular angiography. The cerebral angiography confirmed the model successfully after 4 weeks. Some animals were given paraffin-embedded H-E staining and elastic fiber staining after sacrifice. Angiography was performed for all experiments to build our models and to confirm our findings. Results: Two rabbits died during postoperative feeding, and the remaining 18 rabbits were cultured for 4 weeks and confirmed by angiography to make an aneurysm model. The success rate of aneurysm was 90%, the diameter of the tumor-bearing artery was 3.12±0.20, the short diameter of the tumor was 3.41±0.88, the long diameter of the tumor was 6.30±1.65, and the width of the neck was 3.49±0.80. HE pathology showed that the destruction of the elastic layer of the aneurysm disappeared, similar to the pathological changes of human aneurysms. Conclusions: The rabbit model of aneurysm was established by modified intravascular intervention combined with elastase induction based on angiography. It is similar to human aneurysm in morphology, histology and hemodynamics. The method is simple, the damage is small, the aneurysmal formation rate is high, and the performance is high. Stable and reliable, low production cost, it is an ideal animal model for the development of preclinical neurological interventional devices.

Visualization of Aneurysm Healing : Enhancement Patterns and Reperfusion in Intracranial Aneurysms after Embolization on 3T Vessel Wall MRI.

Wall enhancement of intracranial aneurysms in vessel wall magnetic resonance imaging (MRI) has been linked to aneurysm progression. The clinical significance of aneurysm enhancement after embolization has not yet been investigated. The goal of this study was to identify factors associated with aneurysm wall enhancement and reperfusion after embolization. Patients who underwent treatment of intracranial aneurysms with coils or the Woven Endobridge (WEB) and follow-up MR vessel wall imaging were included. Enhancement of the treated aneurysms was separately recorded for the following locations: a)wall at the neck, b)wall at the dome, and c)in the aneurysmal cavity. Reperfusion was determined on follow-up digital subtraction angiography (DSA) and MR time of flight (TOF) angiography. In this study 48 patients with 53aneurysms were included. Wall enhancement at the neck and the dome of the aneurysm was significantly associated with time between embolization and follow-up MRI under 6months. Enhancement inside the aneurysmal cavity was significantly associated with afollow-up time longer than 6months, and with stable aneurysms without reperfusion. Wall enhancement is aregular feature in intracranial aneurysms after embolization and decreases over time. Enhancement inside the aneurysmal cavity is associated with astable state and could possibly serve as an imaging marker of completed aneurysm healing.

1981 A Case of Jejunal Diverticulum Causing Life-Threatening Hemorrhage

INTRODUCTION: Diverticulosis seldom causes life threatening hemorrhage and is frequently found in the large bowel. Rare cases of small bowel diverticula are most notably known to appear in the duodenum. Even rarer are severe small bowel diverticulum bleeds in the jejunum with one study noting approximately 50 cases reported in the literature. Due to the difficult location, many have gone unidentified and ultimately resulted in small bowel resections. We present a 58-year-old man with a life threatening jejunal diverticular bleed that was diagnosed and treated conservatively. CASE DESCRIPTION/METHODS: A 58-year-old Hispanic male with past medical history significant for upper GI bleed requiring multiple transfusions, chronic pancreatitis, and SMA thrombosis presented to the ED for recurrent melena. He was previously admitted for suspected GI bleed with no identifiable source on colonoscopy, EGD, and outpatient capsule endoscopy. On this admission, vitals were hemodynamically stable but labs revealed a hemoglobin of 3.3. After appropriate resuscitation, push endoscopy revealed a bleeding proximal jejunal diverticulum which was tattooed, coagulated with epinephrine and clipped. CTA of abdomen showed a stable dissecting aneurysm in between the origin of the inferior pancreaticoduodenal arcade and jejunal branches. He was stabilized and discharged with follow up. DISCUSSION: Small bowel diverticulosis is usually found incidentally in asymptomatic patients. Because jejunal diverticuli are novelty differentials, often forgotten, diagnosis becomes delayed even with the use of standard endoscopy, resulting in significant morbidity and mortality. Several noninvasive studies can be done initially to assess for bleeding. With advances in technology such as small bowel enteroscopy, specifically push enteroscopy, jejunal diverticulum can be diagnosed earlier and treated with clipping as opposed to surgical resection which has been the mainstay treatment for refractory bleeding. This case brings to light a rare manifestation of small bowel diverticuli where future research could be dedicated. There has been another case with similar presentation in which the patient also had history of a SMA clot. This poses the question of whether there is a correlation and if it could be explained by the compromised integrity of the small bowel wall due to the lack of blood flow making it easier for diverticuli to arise there. It also raises the question as to why certain patients are more predisposed to developing these outpouchings.

High-frequency murine ultrasound provides enhanced metrics of BAPN-induced AAA growth.

An abdominal aortic aneurysm (AAA), defined as a pathological expansion of the largest artery in the abdomen, is a common vascular disease that frequently leads to death if rupture occurs. Once diagnosed, clinicians typically evaluate the rupture risk based on maximum diameter of the aneurysm, a limited metric that is not accurate for all patients. In this study, we worked to evaluate additional distinguishing factors between growing and stable murine aneurysms toward the aim of eventually improving clinical rupture risk assessment. With the use of a relatively new mouse model that combines surgical application of topical elastase to cause initial aortic expansion and a lysyl oxidase inhibitor, β-aminopropionitrile (BAPN), in the drinking water, we were able to create large AAAs that expanded over 28 days. We further sought to develop and demonstrate applications of advanced imaging approaches, including four-dimensional ultrasound (4DUS), to evaluate alternative geometric and biomechanical parameters between 1) growing AAAs, 2) stable AAAs, and 3) nonaneurysmal control mice. Our study confirmed the reproducibility of this murine model and found reduced circumferential strain values, greater tortuosity, and increased elastin degradation in mice with aneurysms. We also found that expanding murine AAAs had increased peak wall stress and surface area per length compared with stable aneurysms. The results from this work provide clear growth patterns associated with BAPN-elastase murine aneurysms and demonstrate the capabilities of high-frequency ultrasound. These data could help lay the groundwork for improving insight into clinical prediction of AAA expansion.NEW & NOTEWORTHY This work characterizes a relatively new murine model of abdominal aortic aneurysms (AAAs) by quantifying vascular strain, stress, and geometry. Furthermore, Green-Lagrange strain was calculated with a novel mapping approach using four-dimensional ultrasound. We also compared growing and stable AAAs, finding peak wall stress and surface area per length to be most indicative of growth. In all AAAs, strain and elastin health declined, whereas tortuosity increased.

Wall Enhancement in Evolving Cerebral Aneurysms on Magnetic Resonance Vessel Wall Imaging

Abstract INTRODUCTION Recent magnetic resonance (MR) vessel wall imaging studies have indicated cerebral aneurysms in the active state could show wall enhancement along the aneurysm wall (CEAW). While ruptured aneurysms frequently show CEAW, CEAW in the unruptured aneurysms at evolving state, ie growing or symptomatic, has not been studied in detail. We assessed the degree of CEAW in evolving unruptured aneurysms by comparing separately with each of those in stable unruptured aneurysms and ruptured aneurysms. METHODS We performed quantitative analyses of CEAW in consecutive 26 evolving aneurysms using MR vessel wall imaging. Three-dimensional T1-weighted fast spin-echo sequence was obtained before and after contrast media injection, and the contrast ratio of aneurysm wall against the pituitary stalk (CRstalk) was calculated as the indicator of CEAW. We compared aneurysm characteristics of evolving aneurysms with those of 69 stable unruptured and 67 ruptured aneurysms. RESULTS The CRstalk in evolving aneurysms was significantly higher than those in stable aneurysms (0.54 vs 0.34; P &lt; .0001), and lower than those in ruptured aneurysms (0.54 vs 0.83; P &lt; .0002). In multivariable analysis, CRstalk remained significant in comparing evolving with stable aneurysms (odds ratio, 12.23; 95% confidence interval, 3.53-42.41), and with ruptured aneurysms (odds ratio, 0.083; 95% confidence interval, 0.022-0.310). CONCLUSION The CEAW in evolving aneurysms was higher than those in stable aneurysms, and lower than those in ruptured aneurysms.

Clinical Significance of Conversion From Computational Fluid Dynamics to Morphology for Risk Evaluation of Aneurysm Recurrence After Coiling

Abstract INTRODUCTION Hemodynamic factors play a critical role in the recurrence of intracranial aneurysms after coiling. However, the computational fluid dynamics (CFD) analyses are not consistently performed all over the world, and its benefits were limited in the specific institutes. We tried to convert the hemodynamic parameters to morphological factors for the risk evaluation of aneurysm recurrence after coiling. METHODS Using pretreatment 3-dimensional rotational angiography data of 50 internal carotid artery aneurysms (7 recanalized, 43 stable) treated with endovascular coiling, we created a virtual post-coiling model produced by cutting the aneurysm dome for construction of virtual coil plane. At the virtual coil plane, we evaluated the pressure difference, which was defined as the pressure elevation at the coil plane from the parent artery divided by the dynamic pressure at the parent artery. After a statistical analysis of the relationship between the pressure difference and aneurysm recurrence, we performed statistical comparisons of pressure difference with morphological factors. RESULTS Recanalized aneurysms showed a significantly higher pressure difference than stable aneurysms (P &lt; .001). The receiver operating characteristic analysis showed that the area under the curve value for the pressure difference (0.967). Morphologically, all 5 aneurysms that had the virtual coil plane at the line of upper border of internal carotid artery had a significantly higher pressure difference (P &lt; .001) and recurred after coiling (P &lt; .001). CONCLUSION The pressure difference in the virtual post-coiling model had a strong association with aneurysm recurrence after coiling. Additionally, the location of the coil plane as a morphological factor was significantly associated with pressure difference and aneurysm recurrence. The conversion of hemodynamic factors into simple morphological factors may contribute to expanded applications of the CFD analysis.

Correlation Between Laminar Wall Shear Stress and Growth of Unruptured Cerebral Aneurysms: In Vivo Assessment

Cerebral aneurysm growth is significantly associated with aneurysm rupture, but risk factors for aneurysm growth are not well characterized. It is believed that altered intracranial hemodynamics may contribute to the pathophysiology of aneurysm growth, but these mechanisms are not fully understood. Here, we assess the correlation between growth of unruptured cerebral aneurysms over time and average laminar shear stress on the wall of the parent vessel proximal to the aneurysm. Patients with unruptured, untreated cerebral aneurysms followed over time at our institution between 2005 and 2017 were retrospectively reviewed. Patients were included if at least 1 quantitative magnetic resonance angiography study was performed at baseline and follow-up. The nonparametric Wilcoxon-Mann-Whitney test was used to compare mean parent vessel-laminar wall shear stress (PV-LWSS) proximal to the aneurysm in growing versus stable aneurysms. Change in PV-LWSS over time was evaluated using the 1-way repeated measures analysis of variance test. Thirty-three patients with 45 total aneurysms were included (63% female, mean age 60 years). Four patients presented with aneurysm growth over time. Unstable aneurysms had significantly higher PV-LWSS compared with stable aneurysms at the time of first diagnosis (29.3 vs. 13.1 dynes/cm2, P= 0.02) and at 1-year follow-up (25.8 vs. 12.3 dynes/cm2, P= 0.05). The subset of unruptured cerebral aneurysms that demonstrate growth over time has a significantly higher mean PV-LWSS than stable aneurysms, as measured by quantitative magnetic resonance angiography. This information at the time of diagnosis may help predict future aneurysm growth, stratify rupture risk, and identify those aneurysms that should undergo prophylactic treatment.

Intracranial aneurysm rupture score may correlate to the risk of rebleeding before treatment of ruptured intracranial aneurysms.

Aneurysm rebleeding after rupture can result in a catastrophic outcome with high mortality and morbidity. In this study, we evaluated the correlation of IARS (intracranial aneurysm rupture score) and aneurysm rebleeding. The aim of this study was to explore the clinical utility of IARS for better clinical decision-making. The patients with ruptured intracranial aneurysms between January 2017 and September 2018 were reviewed. Propensity scoring match was performed to construct a cohort. The morphological and hemodynamic parameters were obtained. The difference between stable aneurysms and rebleeding aneurysms was compared. Subsequently, the correlation of IARS and aneurysm rebleeding was studied. The matching process constructed a cohort, including 5 rebleeding aneurysms and 15 stable aneurysms. By comparing the difference between stable aneurysms and rebleeding aneurysms, the statistical significance was found in diameter of neck (p = 0.036), aspect ratio (p = 0.004) and size ratio (p = 0.029), normalized wall shear stress average (p = 0.026), low shear area ratio (p = 0.028), oscillatory shear index (OSI) (p = 0.031), and deviated angle (p = 0.025). The IARS here had a strong correlation with the aneurysm rebleeding, and the interval from the first bleeding to the rebleeding tended to shorten with the increase of IARS (R = 0.715, p = 0.027). IARS had a good predicting value for the aneurysm rebleeding (area under the curve = 0.756, p < 0.001). Based on this preliminary study, intracranial aneurysm rupture score may correlate to the rebleeding in ruptured aneurysms. For ruptured aneurysms with high IARS scores, surgery should be given priority, and medical treatment is not recommended.

High Pressure in Virtual Postcoiling Model is a Predictor of Internal Carotid Artery Aneurysm Recurrence After Coiling.

Hemodynamic factors play a crucial role in the recurrence of intracranial aneurysms after coiling. However, the strongest factor for predicting recurrence remains unclear because each risk factor has been investigated and reported separately. To clarify the strongest predictor of recurrence with computational fluid dynamics (CFD). Using pretreatment patient-specific 3-dimensional rotational angiography data of 50 internal carotid artery (ICA) aneurysms (7 recanalized, 43 stable) treated with endovascular coiling, we created a precoiling model and a virtual postcoiling model produced by manually cutting the aneurysm by the flat plane corresponding to the virtual coil surface. We conducted CFD analysis to investigate inflow dynamics in the precoiling model and pressure difference and wall shear stress on the virtual coil surface. The pressure difference was calculated by subtracting average pressure at the proximal ICA from the maximum pressure at the coil surface and dividing by dynamic pressure at the proximal ICA for normalization. We compared hemodynamic parameters in both models between recanalized and stable aneurysms. Compared with stable aneurysms, recanalized aneurysms showed a significantly larger inflow area and higher inflow rate in the precoiling model (P = .016, .028), and higher pressure difference at the coil surface in the postcoiling model (P<.001). The receiver-operating characteristic analysis showed that the area under the curve value for the pressure difference (0.967) was superior to that of other evaluated parameters. The pressure difference in the virtual postcoiling model may be a strong predictor of recurrence after coiling.