On the Importance of Including Cohesive Zone Models in Modelling Mixed-Mode Aneurysm Rupture.

INTRODUCTION: The precise mechanism of rupture in abdominal aortic aneurysms (AAAs) has not yet been uncovered. The phenomenological failure criterion of the coefficient of proportionality between von Mises stress and tissue strength does not account for any mechanistic foundation of tissue fracture. Experimental studies have shown that arterial failure is a stepwise process of fibrous delamination (mode II) and kinking (mode I) between layers. Such a mechanism has not previously been considered for AAA rupture. METHODS: In the current study we consider both von Mises stress in the wall, in addition to interlayer tractions and delamination using cohesive zone models. Firstly, we present a parametric investigation of the influence of a range of AAA anatomical features on the likelihood of elevated interlayer traction and delamination. RESULTS: We observe in several cases that the location of peak von Mises stress and tangential traction coincide. Our simulations also reveal however, that peak von Mises and intramural tractions are not coincident for aneurysms with Length/Radius less than 2 (short high-curvature aneurysms) and for aneurysms with symmetric intraluminal thrombus (ILT). For an aneurysm with (L/R = 2.0), the peak σ vm moves slightly towards the origin while the peak T t is near the peak bulge with a separation distance of ~ 17 mm. Additionally, we present three patient-specific AAA models derived directly from CT scans, which also illustrate that the location of von Mises stress does not correlate with the point of interlayer delamination. CONCLUSION: This study suggests that incorporating cohesive zone models into clinical based FE analyses may capture a greater proportion of ruptures in-silico.

Presumed renal arterial aneurysm in a cat.

A 3-year-old cat was presented for an abdominal ultrasound examination with apathy and anemia. The US revealed the enlargement of the left kidney with a hypoechoic subcapsular thickening. An abnormal, tortuous vessel was visible in the medulla with arterial flow on pulsed-wave Doppler examination. The CT examination confirmed the ultrasound findings and a presumptive diagnosis of the intraparenchymal renal aneurysm was made. Four days later, the cat presented again with a worsening of its condition. The US features were suggestive for that of an aneurysm rupture.

Giant Thoracic Aortic Aneurysm Rupture in a Patient with Extensive Atherosclerotic Disease.

Aneurysmal dilatations can affect any aortic segment and represent the result of various causes, atherosclerotic disease being the most common and frequently involved. We hereby illustrate a case of a patient with thoracic aortic aneurysm rupture due to extensive atherosclerotic disease, with multiple complex penetrating ulcerated atherosclerotic plaques located in the descending aorta. CT angiography evaluation included a comprehensive description of imaging features and extent of the thoracic aortic aneurysm, the presence of thrombus, relationship to adjacent structures and branches, associated complications. Teaching Point: Thoracic aortic aneurysm rupture due to extensive atherosclerotic disease with multiple penetrating ulcers.

Identifying hemodynamic factors associated with the rupture of anterior communicating artery aneurysms based on global modeling of blood flow in the cerebral artery network.

Anterior communicating artery (ACoA) aneurysms are more prone to rupture compared to aneurysms present in other cerebral arteries. We hypothesize that systemic blood flow in the cerebral artery network plays an important role in shaping intra-aneurysmal hemodynamic environment thereby affecting the rupture risk of ACoA aneurysms. The majority of existing numerical studies in this field employed local modeling methods where the physical boundaries of a model are confined to the aneurysm region, which, though having the benefit of reducing computational cost, may compromise the physiological fidelity of numerical results due to insufficient account of systemic cerebral arterial hemodynamics. In the present study, we firstly carried out numerical experiments to address the difference between the outcomes of local and global modeling methods, demonstrating that local modeling confined to the aneurysm region results in inaccurate predictions of hemodynamic parameters compared with global modeling of the ACoA aneurysm as part of the cerebral artery network. Motivated by this finding, we built global hemodynamic models for 40 ACoA aneurysms (including 20 ruptured and 20 unruptured ones) based on medical image data. Statistical analysis of the computed hemodynamic data revealed that maximum wall shear stress (WSS), minimum WSS divergence, and maximum WSS gradient differed significantly between the ruptured and unruptured ACoA aneurysms. Optimal threshold values of high/low WSS metrics were determined through a series of statistical tests. In the meantime, some morphological parameters of aneurysms, such as large nonsphericity index, aspect ratio, and bottleneck factor, were found to be associated closely with aneurysm rupture. Furthermore, multivariate logistic regression analyses were performed to derive models combining hemodynamic and morphological parameters for discriminating the rupture status of aneurysms. The capability of the models in rupture status discrimination was high, with the area under the receiver operating characteristic curve reaching up to 0.9. The findings of the study suggest that global modeling of the cerebral artery network is essential for reliable quantification of hemodynamics in ACoA aneurysms, disturbed WSS and irregular aneurysm morphology are associated closely with aneurysm rupture, and multivariate models integrating hemodynamic and morphological parameters have high potential for assessing the rupture risk of ACoA aneurysms.

Ruptured external iliac artery aneurysm: A case report.

INTRODUCTION: Iliac artery aneurysms are rare, with isolated iliac artery aneurysms responsible for only 2 % of all aneurysmal diseases. External iliac artery (EIA) aneurysms are extremely rare, and the exact cause is unknown. In this case, we report a giant aneurysm without any risk factor presented with rupture and managed by open repair. PRESENTATION OF CASE: An 85-year-old man presented to the emergency department with sudden onset right lower quadrant abdominal pain and vague right lower limb pain. After a complete physical examination, an abdominopelvic CT scan revealed an 80 mm EIA aneurysm containing thrombosis and active leakage. The patient underwent open repair of an aneurysm using a graft between the Aorta and EIA. The surgery was uneventful. Later in the ICU, the patient experienced a cardiac arrest and unfortunately could not recover from it. DISCUSSION: In this case, a patient with a relatively large aneurysm presented with abdominal pain and lower limb discomfort. Although endovascular surgery is recommended for the repair of iliac aneurysms, open repair is common for ruptured aneurysms. Endovascular repair is less invasive but may lead to contrast-induced renal dysfunction. Open repair may induce complications such as sexual dysfunctions, graft infection, and pelvic ischemic conditions. CONCLUSION: EIA aneurysms are exceedingly rare. They may present with a Rupture that puts the patient in critical condition, such as in this case. Due to the hemodynamic instability, open repair is considered one of the main approaches for repairing the aneurysm.

Aneurysm sac shrinkage at 1 year after fenestrated-branched endovascular aortic repair of complex aortic aneurysms offers mid-term survival advantage.

OBJECTIVES: To investigate the impact of 1-year changes in aneurysm sac diameter on patient survival after fenestrated-branched endovascular aortic repair (FB-EVAR) of complex abdominal aortic aneurysms or thoracoabdominal aortic aneurysms. METHODS: We reviewed the clinical data of patients enrolled in a prospective nonrandomized study investigating FB-EVAR (2013-2022). Patients with sequential follow up computed tomography scans at baseline and 6 to 18 months after FB-EVAR were included in the analysis. Aneurysm sac diameter change was defined as the difference in maximum aortic diameter from baseline measurements obtained in centerline of flow. Patients were classified as those with sac shrinkage (≥5 mm) or failure to regress (<5 mm or expansion) according to sac diameter change. The primary end point was all-cause mortality. Secondary end points were aortic-related mortality (ARM), aortic aneurysm rupture (AAR), and aorta-related secondary intervention. RESULTS: There were 549 patients treated by FB-EVAR. Of these, 463 patients (71% male, mean age, 74 ± 8 years) with sequential computed tomography imaging were investigated. Aneurysm extent was thoracoabdominal aortic aneurysms in 328 patients (71%) and abdominal aortic aneurysms in 135 (29%). Sac shrinkage occurred in 270 patients (58%) and failure to regress in 193 patients (42%), including 19 patients (4%) with sac expansion at 1 year. Patients from both groups had similar cardiovascular risk factors, except for younger age among patients with sac shrinkage (73 ± 8 years vs 75 ± 8 years; P < .001). The median follow-up was 38 months (interquartile range, 18-51 months). The 5-year survival estimate was 69% ± 4.1% for the sac shrinkage group and 46% ± 6.2% for the failure to regress group. Survival estimates adjusted for confounders (age, chronic pulmonary obstructive disease, chronic kidney disease, congestive heart failure, and aneurysm extent) revealed a higher hazard of late mortality in patients with failure to regress (adjusted hazard ratio, 1.72; 95% confidence interval, 1.18-2.52; P = .005). The 5-year cumulative incidences of ARM (1.1% vs 3.1%; P = .30), AAR (0.6% vs 2.6%; P = .20), and aorta-related secondary intervention (17.0% ± 2.8% vs 19.0% ± 3.8%) were both comparable between the groups. CONCLUSIONS: Aneurysm sac shrinkage at 1 year is common after FB-EVAR and is associated with improved patient survival, whereas sac enlargement affects only a minority of patients. The low incidences of ARM and AAR indicate that failure to regress may serve as a surrogate marker for nonaortic-related death.

A Comparison of Perioperative Complications and Outcomes in Patients Undergoing Cerebral Aneurysm Clipping Performed Ultra-Early (≤ 24 hours) versus Late (> 24 hours): A 7-Year Retrospective Study of 302 Patients.

Objectives The intracerebral aneurysm with subarachnoid hemorrhage (SAH) has a high morbidity and mortality rate. This study aimed to compare the incidences of perioperative complications in ultra-early surgery (within 24 hours) with those in late surgery (> 24 hours). Methods Retrospective data were reviewed for 302 patients who underwent craniotomies with aneurysm clipping between January 2014 and December 2020. Perioperative data were obtained from the medical records and reviewed by the investigators. The complications were compared between ultra-early and late operations. We were interested in major complications such as delayed ischemic neurologic deficit (DIND), intraoperative aneurysm rupture (IAR), and anesthesia-related complications. The short-term (in hospital) and long-term (1 year) outcomes in patients with or without DIND and IAR were compared. The collected data was statistically analyzed. Results Three hundred and two patients were analyzed, and 264 patients had completed follow-up. The ultra-early cases (150 patients) had a higher American Society of Anesthesiologists physical status, a lower Glasgow Coma Scale, and higher Hunt and Hess scales. The surgeons operated on more cases of the anterior cerebral artery as ultra-early operations. The incidence rates of DIND, IAR, severe hemodynamic instability, and cardiac arrest were 5.6, 8.3, 6.3, and 0.3%, respectively, which were not different between groups. However, the reintubation rate was higher in the ultra-early surgery cases (0 vs. 3.3%, p = 0.023). The DIND and IAR patients had poorer short-term (in hospital) outcomes. Conclusions There were no differences in major complications between ultra-early and late craniotomy with aneurysm clipping. However, the reintubation rate was strikingly higher in the ultra-early group. Patients with major complications had early, unfavorable outcomes.

Intracranial mycotic aneurysm rupture following cupping therapy.

Background: Cupping therapy is an alternative treatment that uses a small glass cup to suck the skin with a needle and has been used to manage skin problems and pain. However, serious complications have been reported. Herein, we describe a case of intracranial mycotic aneurysm rupture after cupping therapy. Case Description: A 25-year-old male patient presented with a headache and fever after cupping therapy for atopic dermatitis. He was diagnosed with infective endocarditis, and antibiotic therapy was initiated. After that, he suddenly lost consciousness, and head imaging revealed a cerebral hemorrhage due to a ruptured intracranial mycotic aneurysm. He underwent craniotomy, which was successful, and he was transferred to a rehabilitation center with a modified Rankin scale score of 2 at three months post-stroke. Conclusion: This case serves as a reminder of life-threatening infectious complication risks after cupping therapy. A patient who has a compromised skin barrier may experience serious adverse effects, especially when cupping is performed without implementing suitable infection prevention measures.

Traumatic Aneurysm Involving the Posterior Communicating Artery.

Traumatic intracranial aneurysms (TICAs) are rare, accounting for less than 1% of all intracranial aneurysms. However, they are associated with a mortality rate of over 50%. The case presented herein focuses on a posterior communicating artery TICA caused by violent aggression. A 41-year-old man with massive subarachnoid hemorrhage (SAH), on admission to hospital, had a CT angiography that showed a ruptured left posterior communicating artery aneurysm with continuous blood loss and underwent neurosurgical cooling. The CT scan also showed fractures of the mandible, mastoid and left styloid process, as well as brain contusions caused by blows and kicks. Despite medical treatment and surgery, after four days, he died. The assault dynamics were recorded by a camera in the bar. The damage was caused by kicks to the neck and head. The forensic neuropathological examination showed the primary injury (SAH, subdural hemorrhage, cerebral contusions, head-neck fractures), as well as secondary damage following the attack (cerebral infarcts, edema, supratentorial hernia, midbrain hemorrhage). The coil was intact and well positioned. In this case, circumstantial information, medical records, and the type of injury could shed light on the mechanism of the production of a TICA. In addition, the CT angiography and histological investigations helped to distinguish a recent and traumatic aneurysm from a pre-existing one. Following precise steps, the study of aneurysms can be helpful in clarifying their traumatic origin even when the victim was taking drugs. The aim of this study is also to share the diagnostic process that we used in the forensic field for the assessment of suspected traumatic aneurysms.

Dietary Iron Restriction Protects against Aneurysm Rupture in a Mouse Model of Intracranial Aneurysm.

INTRODUCTION: Iron accumulation in vessel walls induces oxidative stress and inflammation, which can cause cerebrovascular damage, vascular wall degeneration, and intracranial aneurysmal formation, growth, and rupture. Subarachnoid hemorrhage from intracranial aneurysm rupture results in significant morbidity and mortality. This study used a mouse model of intracranial aneurysm to evaluate the effect of dietary iron restriction on aneurysm formation and rupture. METHODS: Intracranial aneurysms were induced using deoxycorticosterone acetate-salt-induced hypertension and a single injection of elastase into the cerebrospinal fluid of the basal cistern. Mice were fed an iron-restricted diet (n = 23) or a normal diet (n = 25). Aneurysm rupture was detected by neurological symptoms, while the presence of intracranial aneurysm with subarachnoid hemorrhage was confirmed by post-mortem examination. RESULTS: The aneurysmal rupture rate was significantly lower in iron-restricted diet mice (37%) compared with normal diet mice (76%; p < 0.05). Serum oxidative stress, iron accumulation, macrophage infiltration, and 8-hydroxy-2'-deoxyguanosine in the vascular wall were lower in iron-restricted diet mice (p < 0.01). The areas of iron positivity were similar to the areas of CD68 positivity and 8-hydroxy-2'-deoxyguanosine in both normal diet and iron-restricted diet mouse aneurysms. CONCLUSIONS: These findings suggest that iron is involved in intracranial aneurysm rupture via vascular inflammation and oxidative stress. Dietary iron restriction may have a promising role in preventing intracranial aneurysm rupture.

Neutrophils: Novel Contributors to Estrogen-Dependent Intracranial Aneurysm Rupture Via Neutrophil Extracellular Traps.

Background Intracranial aneurysms (IAs) are more prevalent in women than men, and aneurysmal subarachnoid hemorrhage disproportionately affects postmenopausal women. These sex differences suggest estrogen protects against IA progression that can lead to rupture, but the underlying mechanisms are not fully understood. Although studies have demonstrated estrogen regulates inflammatory processes that contribute to IA pathogenesis, the role of neutrophils remains to be characterized. Using a murine model, we tested our hypothesis that neutrophils contribute to IA pathophysiology in an estrogen-dependent manner. Methods and Results We compared neutrophil infiltration in C57BL/6 female mice that develop IAs to those with a normal circle of Willis. Next, we investigated the estrogen-dependent role of neutrophils in IA formation, rupture, and symptom-free survival using a neutrophil depletion antibody. Finally, we studied the role of neutrophil extracellular trap formation (NETosis) as an underlying mechanism of aneurysm progression. Mice that developed aneurysms had increased neutrophil infiltration compared with those with a normal circle of Willis. In estrogen-deficient female mice, both neutrophil depletion and NETosis inhibition decreased aneurysm rupture. In estrogen-deficient female mice treated with estrogen rescue and estrogen-intact female mice, neither neutrophil depletion nor NETosis inhibition affected IA formation, rupture, or symptom-free survival. Conclusions Neutrophils contribute to aneurysm rupture in an estrogen-dependent manner. NETosis appears to be an underlying mechanism for neutrophil-mediated IA rupture in estrogen deficiency. Targeting NETosis may lead to the development of novel therapeutics to protect against IA rupture in the setting of estrogen deficiency.

Analysis of independent risk factors for aneurysm rupture based on carotid tortuosity index and morphological parameters of single intracranial aneurysms in anterior circulation.

PURPOSE: Our study focused on the risk factors associated with anterior circulation intracranial aneurysm (IA) rupture by examining the carotid artery (CA) tortuosity index (TI) and anterior circulation IA morphological parameters. METHOD: This study conducted a retrospective analysis of clinical and imaging data from 163 patients with anterior circulation IA diagnosed by head and neck computed tomography angiography (CTA). The patients were categorized into two groups: the ruptured group (57 cases) and the unruptured group (106 cases). CA was categorized based on its location into three segments: the extracranial segment of the internal carotid artery (EICA) TI, the angle of the internal carotid artery (ICA) and the common carotid artery (CCA) TI. Measure the morphological parameters of all IA: IA length neck (L), IA height (H), aneurysm diameter width (D), the ratio of L to the mean diameter of the IA-bearing artery (SR), the ratio of H to D (AR), the angle of flow inflow (FA) and IA angle (AA). The study conducted five types of analysis to determine the risk factors for anterior circulation IA rupture. The first was an univariate analysis of the risk factors. The second was an analysis of the correlation between CA TI and IA morphological parameters. The third used multivariate logistic stepwise regression analysis to analyse independent risk factors for IA rupture. The fourth was to plot ROC curves to build a predictive model for IA rupture and calculate diagnostic thresholds. Finally, a data set from another hospital (78 cases) was used as a validation set to validate the multivariate model. RESULT: Univariate analysis revealed that there were statistically significant differences (P < 0.05) in gender, EICA TI, location of IA and IA morphological parameters (FA, H, AR, L, SR), which acted as risk factors for anterior circulation IA rupture. The results of Spearman correlation analysis indicate that CCA TI is significantly correlated with SR, H and L (P < 0.05), while EICA TI is significantly correlated with FA and L (P < 0.05). The results of multivariate logistic analysis showed that FA (OR = 1.072, 95%CI = 1.04-1.10, P < 0.001), SR (OR = 4.949, 95%CI = 1.96-12.53, P = 0.001), EICA TI (OR = 1.037, 95%CI = 1.01-1.07, P = 0.003) were independent risk factors for IA rupture. The ROC curve plotting results suggest that the area under the curve (AUC) of FA is 0.860 with a diagnostic threshold of 110.1°; the AUC of SR is 0.786 with a diagnostic threshold of 1.67; the AUC of EICA TI is 0.723 with a diagnostic threshold of 28.845; the AUC of the three combined is 0.903 with a threshold of 0.480. The combined factor diagnostic model is validated according to the validation set, and the results show that the AUC (0.866) of the validation set is not much different from the AUC (0.903) of the multivariate model, and the multivariate model has a better diagnostic effect. CONCLUSION: In clinical practice, it is important to consider the evaluation of aneurysm rupture in combination with imaging, as FA, SR and ECIA TI are independent risk factors for IA rupture in the anterior circulation. Unlike the IA morphological parameters, EICA TI is an often overlooked extracranial parameter, but is equally important in its power to predict IA rupture. When the EICA TI exceeds 28.845, the IA has the possibility of rupture. Finally, multivariate diagnostic model are of interest when considering rupture of the anterior circulation IA.

The Role of NF-κB in Intracranial Aneurysm Pathogenesis: A Systematic Review.

Intracranial aneurysms (IAs) are abnormal dilations of the cerebral vessels, which pose a persistent threat of cerebral hemorrhage. Inflammation is known to contribute to IA development. The nuclear factor "kappa-light-chain-enhancer" of activated B-cells (NF-κB) is the major driver of inflammation. It increases the expression of inflammatory markers and matrix metalloproteinases (MMPs), which contribute heavily to the pathogenesis of IAs. NF-κB activation has been linked to IA rupture and resulting subarachnoid hemorrhage. Moreover, NF-κB activation can result in endothelial dysfunction, smooth muscle cell phenotypic switching, and infiltration of inflammatory cells in the arterial wall, which subsequently leads to the initiation and progression of IAs and consequently results in rupture. After a systematic search, abstract screening, and full-text screening, 30 research articles were included in the review. In this systematic review, we summarized the scientific literature reporting findings on NF-κB's role in the pathogenesis of IAs. In conclusion, the activation of the NF-κB pathway was associated with IA formation, progression, and rupture.

Endovascular and Open Surgical Treatment of Ruptured Splenic Artery Aneurysms: A Case Report and a Systematic Literature Review.

BACKGROUND: Ruptured splenic artery aneurysms (r-SAA), although rare, are burdened by high morbidity and mortality, even despite emergent surgical repair. It is suggested that endovascular treatment can achieve reduction in peri-operative death and complication rates, as in other vascular diseases, but evidence of such benefits is still lacking in this particular setting. We report a case of an r-SAA treated by trans-arterial embolization and then converted to open surgery for persistent bleeding, and we provide a systematic review of current results of open and endovascular repair of r-SAAs. MATERIALS AND METHODS: A 50-year-old male presenting in shock for a giant r-SAA underwent emergent coil embolization and recovered hemodynamic stability. On the following day, he underwent laparotomy for evacuation of the huge intraperitoneal hematoma, but residual bleeding was noted from the splenic artery, which was ligated after coil removal, and a splenectomy was performed. A systematic literature review of the reported mortality and complications of r-SAA undergoing open (OSR) or endovascular (EVT) treatment was performed using the main search databases. All primary examples of research published since 1990 were included regardless of sample size. The main outcome measures were mortality and reinterventions. Secondary outcomes were post-operative complications. RESULTS: We selected 129 studies reporting on 350 patients-185 treated with OSR and 165 with EVT. Hemodynamically unstable patients and ruptures during pregnancy were more frequently treated with open repair. Overall, there were 37 deaths (mortality: 10.6%)-24 in the OSR group and 13 in the EVTr group (mortality: 12.9% and 7.8% respectively, p-value: 0.84). There were 37 reinterventions after failed or complicated endovascular repair -6 treated with endovascular re-embolization and 31 with laparotomy and splenectomy (22.4%); there were 3 (1.6%) reinterventions after open repair. Overall complication rates were 7.3% in the EVT group (n: 12) and 4.2% in the OSR group (n: 7), and did not require reintervention. No significant differences in overall complications or in any specific complication rate were observed between the two groups. CONCLUSIONS: Current results of r-SAA treatment show equipoise terms of morbidity and mortality between open and endovascular repair; however, in case of hemodynamic instability and rupture during pregnancy, open surgery might still be safer. Moreover, endovascular repair is still burdened by a significantly higher rate of reinterventions, mostly with conversions to open surgery.

Case report: Unveiling the unforeseen: a catastrophic encounter of giant aortic aneurysm rupture during re-sternotomy in a patient with bicuspid aortic valve and previous surgical aortic valve replacement.

Due to structural abnormalities in the leaflets, patients with bicuspid aortic valve (BAV) may develop isolated aortic valve disease, such as aortic regurgitation, aortic stenosis, or a combination of both. In addition to valvular pathology, numerous studies have indicated that approximately 40% of BAV patients exhibit aortic pathologies characterized by aortic dilatation. According to guidelines for valvular diseases, patients with BAV who require surgical aortic valve replacement (SAVR) and have a diameter of the aortic sinuses or ascending aorta ≥4.5 cm are recommended to undergo concomitant replacement of the aortic sinuses or ascending aorta. However, we encountered a case in 2020 involving a patient with severe aortic regurgitation due to BAV and an ascending aortic diameter of 4.2 cm. This patient underwent SAVR and ascending aortoplasty surgery at our center. Remarkably, three years postoperatively, the patient's aortic diameter rapidly expanded by nearly threefold, which also suggests the risk of encountering a giant aortic root aneurysm during reoperation. Unfortunately, a fatal rupture of a giant aortic root aneurysm was encountered during re-sternotomy. Fortunately, with adequate preoperative planning, we successfully managed to avert this perilous situation. The patient recovered without complications and was discharged on the 8th day. Individualized surgical plans were formulated based on a comprehensive evaluation of the perioperative conditions.

Early Relative Growth Rate of Abdominal Aortic Aneurysms and Future Risk of Rupture or Repair.

OBJECTIVE: This study aimed to test whether the relative growth rate of subthreshold abdominal aortic aneurysms (AAAs) in the first 24 months of surveillance predicts the risk of future rupture or repair. METHODS: This was a single centre retrospective observational analysis of all small (< 45 mm diameter) and medium (45 - 54 mm in men, 45 - 50 mm in women) AAAs entered into ultrasound surveillance between January 2002 and December 2019, which received ≥ 24 months of surveillance. Relative growth rates were calculated from measurements taken in the first 24 months of surveillance. The Kaplan-Meier method was used to estimate intervention and rupture free proportions five years following diagnosis for AAAs growing by < 5% and by ≥ 5% in the first 24 months of surveillance. Multivariable Cox regression analysis was used to further analyse this relationship by adjusting for factors found to be significantly associated with outcome in univariable analysis. RESULTS: A total of 556 patients with AAAs (409 men, 147 women) were followed for ≥ 24 months. This included 431 small AAAs. Of these, 109 (25.3%) grew by < 5% in the first 24 months of surveillance and had a cumulative event free proportion of 0.98 ± 0.05 at five years compared with 0.78 ± 0.05 for the ≥ 5% growth group (p < .001). Of 125 medium AAAs, 26 (20.8%) grew by < 5% in the first 24 months of surveillance and had a cumulative event free proportion of 0.73 ± 0.11 at five years compared with 0.29 ± 0.13 for the ≥ 5% growth group (p = .024). Baseline diameter and early relative growth rate were strongly and independently predictive of future intervention or rupture with hazard ratios of 9.16 (95% CI 5.98 - 14.03, p < .001) and 4.46 (95% CI 2.45 - 8.14, p < .001), respectively. CONCLUSION: The results suggest that slow expansion of small (< 45 mm) AAAs observed over an isolated 24 month period is indicative of a very low risk of rupture or repair in the medium term. Isolated growth rates may be a useful tool with which to triage low risk AAAs and prevent unnecessary surveillance.

StrokeNet: An automated approach for segmentation and rupture risk prediction of intracranial aneurysm.

Intracranial Aneurysms (IA) present a complex challenge for neurosurgeons as the risks associated with surgical intervention, such as Subarachnoid Hemorrhage (SAH) mortality and morbidity, may outweigh the benefits of aneurysmal occlusion in some cases. Hence, there is a critical need for developing techniques that assist physicians in assessing the risk of aneurysm rupture to determine which aneurysms require treatment. However, a reliable IA rupture risk prediction technique is currently unavailable. To address this issue, this study proposes a novel approach for aneurysm segmentation and multidisciplinary rupture prediction using 2D Digital Subtraction Angiography (DSA) images. The proposed method involves training a fully connected convolutional neural network (CNN) to segment aneurysm regions in DSA images, followed by extracting and fusing different features using a multidisciplinary approach, including deep features, geometrical features, Fourier descriptor, and shear pressure on the aneurysm wall. The proposed method also adopts a fast correlation-based filter approach to drop highly correlated features from the set of fused features. Finally, the selected fused features are passed through a Decision Tree classifier to predict the rupture severity of the associated aneurysm into four classes: Mild, Moderate, Severe, and Critical. The proposed method is evaluated on a newly developed DSA image dataset and on public datasets to assess its generalizability. The system's performance is also evaluated on DSA images annotated by expert neurosurgeons for the rupture risk assessment of the segmented aneurysm. The proposed system outperforms existing state-of-the-art segmentation methods, achieving an 85 % accuracy against annotated DSA images for the risk assessment of aneurysmal rupture.

Predictive Model Evaluating Risk of Hemorrhage in Intracranial Aneurysms: Analysis from Prospectively Collected HEAT Trial Database.

OBJECTIVE: We analyzed the data of patients enrolled in the Hydrogel Endovascular Aneurysm Treatment (HEAT) trial to develop and validate a model to predict the risk of aneurysmal hemorrhage. METHODS: Analysis included data from 600 patients enrolled for the HEAT trial and included single saccular aneurysms of 3-14 mm size. Baseline characteristics were compared between patients with ruptured and unruptured aneurysms. Regression analysis was performed in the training set to identify significant risk factors and was validated in the validation dataset. The complete dataset was used to formulate a scoring model in which positive and negative predictors were assigned 1 and -1 points, respectively. RESULTS: Data from 593 patients were analyzed in which 169 (28.5%) patients had ruptured aneurysms. The training (n = 297) and validation dataset (n = 296) had a comparable proportion of ruptured aneurysms (29.3% and 27.7%). Dome-to-neck ratio >2.5 (odds ratio [OR] 3.66), irregular shape (OR 3.79), daughter sac (OR 5.89), and anterior and posterior communicating artery locations (OR 3.32 and 3.56, respectively) had a higher rupture rate. Use of aspirin was associated with lower risk of hemorrhage (OR 0.16). The area under the curve from the receiver operating curve analysis was 0.88, 0.87, and 0.87 in the training, validation, and combined data set, respectively. The scoring model created a score of -1 to 2, yielding an of aneurysmal hemorrhage probability from 1.5% (score -1) to 70% (score 2). CONCLUSIONS: This prospective study identifies dome-to-neck ratio >2.5, irregular shape, presence of daughter sac, absence of aspirin use, and aneurysm location at anterior communicating and posterior communicating artery as factors associated with increased risk of hemorrhagic presentation in small- to medium-sized intracranial aneurysms. Our model provides an estimate of rupture risk based on the presence or absence of these factors.

Renin-Angiotensin-Aldosterone System Inhibitors Are Associated With Favorable Outcomes Compared to Beta Blockers in Reducing Mortality Following Abdominal Aneurysm Repair.

Background The best medical therapy to control hypertension following abdominal aortic aneurysm repair is yet to be determined. We therefore examined whether treatment with renin-angiotensin-aldosterone system inhibitors (RAASIs) versus beta blockers influenced postoperative and 1-year clinical end points following abdominal aortic aneurysm repair in a Medicare-linked database. Methods and Results All patients with hypertension undergoing endovascular aneurysm repair and open aneurysm repair in the Vascular Quality Initiative Vascular Implant Surveillance and Interventional Outcomes Network database between 2003 and 2018 were included. Patients were divided into 2 groups based on their preoperative and discharge medications, either RAASIs or beta blockers. Our cohort included 8789 patients, of whom 3523 (40.1%) were on RAASIs, and 5266 (59.9%) were on beta blockers. After propensity score matching, there were 3053 matched pairs of patients in each group. After matching, RAASI use was associated with lower risk of postoperative mortality (odds ratio [OR], 0.3 [95% CI, 0.1-0.6]), myocardial infarction (OR, 0.1 [95% CI, 0.03-0.6]), and nonhome discharge (OR, 0.6 [95% CI, 0.5-0.7]). Before propensity score matching, RAASI use was associated with lower 1-year mortality (hazard ratio [HR], 0.4 [95% CI, 0.4-0.5]) and lower risk of aneurysmal rupture (HR, 0.7 [95% CI, 0.5-0.9]). These results persisted after propensity score matching for mortality (HR, 0.4 [95% CI, 0.4-0.5]) and aneurysmal rupture (HR, 0.7 [95% CI, 0.5-0.9]). Conclusions In this large contemporary retrospective cohort study, RAASI use was associated with favorable postoperative outcomes compared with beta blockers. It was also associated with lower mortality and aneurysmal rupture at 1 year of follow-up.