Statistical evaluation of measured biomechanical properties of human brain aneurysm samples.

Background and purpose:

Human brain aneurysms may often prove fatal if not re­cognized in time and treated accordingly. The understanding of development and rupture of aneurysms can significantly be improved by the application of numerical modelling, which in turn, requires the knowledge of mechanical properties of vessel wall. This study aims to identify assumed differences with respect to age, sex, spatial orientation, and rupture by utilizing detailed statistical analysis of uniaxial tensile measurements of human brain aneurysm samples, performed by the authors in a previous project.

At surgery of 42 patients, aneu­rysm fundi were cut distally to the clip. In each case, depending on size, varying number of stripes (altogether 88) were prepared and uniaxial stress-strain measurements were performed. Quantities related to the capacity, energy absorption or stiffness were determined and statistically analysed.

The number of specimens in the aneurysm sample was sufficient to establish statistical differences with respect to sex and rupture (p<0.05). No significant differences were detected in orientation, though higher values of stresses and deformations were ob­tained in the circumferential direction com­pared to the meridional direction. 

Significant differences bet­ween sexes with respect to ultimate deformations were demonstrated according to expectation, and the hypothesis on equality of energy capacity could be supported. Similarity of curves with respect to specimen orientation was also observed and ruptured aneurysm sacs tended to be smaller in size. It seems that differences and trends described in this paper are realistic and need to be applied in numerical modelling.

Verification of a simplified aneurysm dimensionless flow parameter to predict intracranial aneurysm rupture status.

OBJECTIVES: Aneurysm number (An) is a novel prediction tool utilizing parameters of pulsatility index (PI) and aneurysm geometry. An has been shown to have the potential to differentiate intracranial aneurysm (IA) rupture status. The objective of this study is to investigate the feasibility and accuracy of An for IA rupture status prediction using Australian based clinical data. METHODS: A retrospective study was conducted across three tertiary referral hospitals between November 2017 and November 2020 and all saccular IAs with known rupture status were included. Two sets of An values were calculated based on two sets of PI values previously reported in the literature. RESULTS: Five hundred and four IA cases were included in this study. The results demonstrated no significant difference between ruptured and unruptured status when using An ≥1 as the discriminator. Further analysis showed no strong correlation between An and IA subtypes. The area under the curve (AUC) indicated poor performance in predicting rupture status (AUC1 = 0.55 and AUC2 = 0.56). CONCLUSIONS: This study does not support An ≥1 as a reliable parameter to predict the rupture status of IAs based on a retrospective cohort. Although the concept of An is supported by hemodynamic aneurysm theory, further research is needed before it can be applied in the clinical setting. ADVANCES IN KNOWLEDGE: This study demonstrates that the novel prediction tool, An, proposed in 2020 is not reliable and that further research of this hemodynamic model is needed before it can be incorporated into the prediction of IA rupture status.

Contemporary management of aneurysmal subarachnoid haemorrhage. An update for the intensivist.

Aneurysmal subarachnoid haemorrhage (aSAH) is a rare yet profoundly debilitating condition associated with high global case fatality and morbidity rates. The key determinants of functional outcome include early brain injury, rebleeding of the ruptured aneurysm and delayed cerebral ischaemia. The only effective way to reduce the risk of rebleeding is to secure the ruptured aneurysm quickly. Prompt diagnosis, transfer to specialized centers, and meticulous management in the intensive care unit (ICU) significantly improved the prognosis of aSAH. Recently, multimodality monitoring with specific interventions to correct pathophysiological imbalances has been proposed. Vigilance extends beyond intracranial concerns to encompass systemic respiratory and haemodynamic monitoring, as derangements in these systems can precipitate secondary brain damage. Challenges persist in treating aSAH patients, exacerbated by a paucity of robust clinical evidence, with many interventions showing no benefit when tested in rigorous clinical trials. Given the growing body of literature in this field and the issuance of contemporary guidelines, our objective is to furnish an updated review of essential principles of ICU management for this patient population. Our review will discuss the epidemiology, initial stabilization, treatment strategies, long-term prognostic factors, the identification and management of post-aSAH complications. We aim to offer practical clinical guidance to intensivists, grounded in current evidence and expert clinical experience, while adhering to a concise format.

Intraoperative neuromonitoring as real-time diagnostic for cerebral ischemia in endovascular treatment of ruptured brain aneurysms.

OBJECTIVE: To evaluate the diagnostic accuracy of intraoperative neurophysiological monitoring (IONM) during endovascular treatment (EVT) of ruptured intracranial aneurysms (rIA). METHODS: IONM and clinical data from 323 patients who underwent EVT for rIA from 2014-2019 were retrospectively reviewed. Significant IONM changes and outcomes were evaluated based on visual review of data and clinical documentation. RESULTS: Of the 323 patients undergoing EVT, significant IONM changes were noted in 30 patients (9.29%) and 46 (14.24%) experienced postprocedural neurological deficits (PPND). 22 out of 30 (73.33%) patients who had significant IONM changes experienced PPND. Univariable analysis showed changes in somatosensory evoked potential (SSEP) and electroencephalogram (EEG) were associated with PPND (p-values: <0.001 and <0.001, retrospectively). Multivariable analysis showed that IONM changes were significantly associated with PPND (Odd ratio (OR) 20.18 (95%CI:7.40-55.03, p-value: <0.001)). Simultaneous changes in both IONM modalities had specificity of 98.9% (95% CI: 97.1%-99.7%). While sensitivity when either modality had a change was 47.8% (95% CI: 33.9%-62.0%) to predict PPND. CONCLUSIONS: Significant IONM changes during EVT for rIA are associated with an increased risk of PPND. SIGNIFICANCE: IONM can be used confidently as a real time neurophysiological diagnostic guide for impending neurological deficits during EVT treatment of rIA.

Impact of fludrocortisone on the outcomes of subarachnoid hemorrhage patients: A retrospective analysis.

BACKGROUND: Whether the use of fludrocortisone affects outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH). METHODS: We conducted a retrospective analysis of 78 consecutive patients with a ruptured aSAH at a single academic center in the United States. The primary outcome was the score on the modified Rankin scale (mRS, range, 0 [no symptoms] to 6 [death]) at 90 days. The primary outcome was adjusted for age, hypertension, aSAH grade, and time from aSAH onset to aneurysm treatment. Secondary outcomes were neurologic and cardiopulmonary dysfunction events. RESULTS: Among 78 patients at a single center, the median age was 58 years [IQR, 49 to 64.5]; 64 % were female, and 41 (53 %) received fludrocortisone. The adjusted common odds ratio, aOR, of a proportional odds regression model of fludrocortisone use with mRS was 0.33 (95 % CI, 0.14-0.80; P = 0.02), with values <1.0 favoring fludrocortisone. Organ-specific dysfunction events were not statistically different: delayed cerebral ischemia (22 % vs. 39 %, P = 0.16); cardiac dysfunction (0 % vs. 11 %; P = 0.10); and pulmonary edema (15 % vs. 8 %; P = 0.59). CONCLUSIONS: The risk of disability or death at 90 days was lower with the use of fludrocortisone in aSAH patients.

Epithelial-mesenchymal transition related genes in unruptured aneurysms identified through weighted gene coexpression network analysis.

Intracranial aneurysm (IA) can cause fatal subarachnoid hemorrhage (SAH) after rupture, and identifying patients with unruptured IAs is essential for reducing SAH fatalities. The epithelial-mesenchymal transition (EMT) may be vital to IA progression. Here, identified key EMT-related genes in aneurysms and their pathogenic mechanisms via bioinformatic analysis. The GSE13353, GSE75436, and GSE54083 datasets from Gene Expression Omnibus were analyzed with limma to identify differentially expressed genes (DEGs) among unruptured aneurysms, ruptured aneurysms, and healthy samples. The results revealed that three EMT-related DEGs (ADIPOQ, WNT11, and CCL21) were shared among all groups. Coexpression modules and hub genes were identified via weighted gene co-expression network analysis, revealing two significant modules (red and green) and 14 EMT-related genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggested that cytokine interactions were closely related. Gene set enrichment analysis revealed that unruptured aneurysms were enriched for the terms "inflammatory response" and "vascular endothelial growth". Protein-protein interaction analysis identified seven key genes, which were evaluated with the GSE54083 dataset to determine their sensitivity and specificity. In the external validation set, we verified the differential expression of seven genes in unruptured aneurysms and normal samples. Together, these findings indicate that FN1, and SPARC may help distinguish normal patients from patients with asymptomatic IAs.

Intentional Bilateral Renal Artery Coverage During Ruptured Endovascular Paraanastomotic Pseudoaneurysm Repair.

The development of a paraanastomotic pseudoaneurysm is a serious complication after open prosthetic reconstruction of the aorta for occlusive or aneurysmal disease. Open repair of these lesions has previously been associated with high rates of morbidity and mortality. Endovascular repair may provide suitable treatment for proximal paraanastomotic aortic bypass graft pseudoaneurysms in patients who are poor candidates for open surgery. Bilateral renal artery coverage may be necessary to achieve adequate fixation and seal during life-threatening emergency cases of pseudoaneurysm rupture. Due to the infrequency of reported cases, the consequences of bilateral renal artery occlusion during these complex procedures are poorly understood. We present a case of a proximal paraanastomotic aortobifemoral bypass pseudoaneurysm rupture that was managed using endovascular repair with intentional coverage of both renal arteries. We also review the contemporary literature on endovascular management of paraanastomotic aneurysms and discuss the role of bilateral renal artery coverage in treating select patients with complex ruptured aortic pathology.

Newly Identified Hemodynamic Parameter to Predict Thin-Walled Regions of Unruptured Cerebral Aneurysms Using Computational Fluid Dynamics Analysis.

BACKGROUND: The thin-walled regions (TIWRs) of intracranial aneurysms have a high risk of rupture during surgical manipulation. They have been reported to be predicted by wall shear stress and pressure (PS) based on computational fluid dynamics analysis, although this remains controversial. In this study, we investigated whether the oscillatory shear index (OSI) can predict TIWRs. METHODS: Twenty-five unruptured aneurysms were retrospectively analyzed; the position and orientation of the computational fluid dynamics color maps were adjusted to match the intraoperative micrographs. The red area on the aneurysm wall was defined as TIWR, and if most of the regions on the color map corresponding to TIWR were OSI low (lower quartile range), time-averaged wall shear stress (TAWSS) high, or PS high (upper quartile range), each region was defined as a matched region and divided by the total number of TIWRs to calculate the match rate. In addition, the mean values of OSI, TAWSS, and PS corresponding to TIWRs were quantitatively compared with those in adjacent thick-walled regions. RESULTS: Among 27 TIWRs of 25 aneurysms, 23, 10, and 14 regions had low OSI, high TAWSS, and high PS regions (match rate: 85.2%, 37.0%, and 51.9%), respectively. Receiver operating characteristic curve analysis demonstrated that OSI was the most effective hemodynamic parameter (area under the curve, 0.881), followed by TAWSS (0.798). Multivariate analysis showed that OSI was a significant independent predictor of TIWRs (odds ratio, 18.30 [95% CI, 3.2800-102.00], P < 0.001). CONCLUSIONS: OSI may be a unique predictor for TIWRs. Low OSI strongly corresponds with TIWRs of intracranial aneurysms.

Flow Diversion in Acute Sub Arachnoid Haemorrhage: A Single Centre Five Year Experience.

OBJECTIVES: The role of flow-diversion in acute sub-arachnoid haemorrhage (SAH) is controversial. Many of the published data warns of high rates of procedure-related complications and aneurysmal rebleed. This study evaluates the safety, efficacy, clinical and angiographic outcomes of acute flow-diversion at our institute. METHODS: The institutional database from June 2015 to June 2020 was retrospectively reviewed for aneurysmal SAH (aSAH) treated with flow diversion. Clinical presentation, procedural details, complications, anti-platelet usage, rebleeding and aneurysm occlusion rates and outcomes were recorded. RESULTS: 22 (59% females; median age 56 years) consecutive patients were identified. None of them were on regular antiplatelets/anticoagulation in the 15-days preceding the treatment. The mean aneurysm diameter was 5.4 mm and the median delay to flow-diversion was 2 days. Almost 73% (16/22) of patients had adjunctive coiling in the same session. There was no aneurysmal rebleed at a median follow up of 8.5 months and 86.3% (19/22 patients) had good clinical outcomes (3-month MRS 0-2). Adverse events related to the flow diversion procedure were seen in 3 patients; none of them had a medium to long-term clinical consequence. Three patients died from complications of SAH, unrelated to the procedure. Vascular imaging follow-up was available for 20 patients and the complete aneurysm occlusion rate was 95%. CONCLUSION: Flow-diversion could be a reasonably safe and effective technique for treating ruptured aneurysms in appropriately selected patients when conventional options of surgical clipping and coiling are considered challenging.

Enigma of what is Known about Intracranial Aneurysm Occlusion with Endovascular Devices.

Aneurysmal subarachnoid Hemorrhage is a major cause of neurological morbidity and mortality. Over the years vascular neurosurgery has witnessed technological advances aimed to reduce the morbidity and mortality. Several endovascular devices have been used in clinical practice to achieve this goal in the management of ruptured and unruptured cerebral aneurysms. Recurrence due to recanalization is encountered in all of these endovascular devices as well as illustrated by Barrow Ruptured Aneurysm Trial. Histological and molecular characterization of the aneurysms treated with endovascular devices is an area of active animal and human research studies. Yet, the pathobiology illustrating the mechanisms of aneurysmal occlusion and healing lacks evidence. The enigma of aneurysmal healing following treatment with endovascular devices needs to be de-mystified to understand the biological interaction of endovascular device and aneurysm and thereby guide the future development of endovascular devices aimed at better aneurysm occlusion. We performed a comprehensive and detailed literature review to bring all the known facts of the pathobiology of intracranial aneurysm healing, the knowledge of which is of paramount importance to neurosurgeons, an interventional neuroradiologist, molecular biologist, geneticists, and experts in animal studies. This review serves as a benchmark of what is known and platform for future studies basic science research related to intracranial aneurysms.

Cross-over Deployment of a Tapered Stent Graft to Repair a Ruptured Isolated Internal Iliac Aneurysm.

We report the case of a 72-year-old man who presented with a left ruptured internal iliac aneurysm (IIA). A percutaneous cross-over approach was used to coil-embolize the 3 distal branches of the IIA. A tapered endograft limb was then delivered via the right common femoral artery using a femorofemoral through-and-through cross-over approach. The widest part of the graft was deployed in the common iliac artery and the smallest in the external iliac artery. This percutaneous endovascular technique opens up new perspectives in emergency care for ruptured internal iliac artery aneurysms.

Clinical and radiological outcomes in relation with the anatomical orientation of clipped middle cerebral artery bifurcation aneurysms.

BACKGROUND: The middle cerebral artery (MCA) bifurcation represents the most frequent location for intracranial aneurysms. Often, the aneurysmal dome can hide the origin of perforating arteries from the M1 segment during the surgical clipping causing ischemic lesions and worse clinical outcome. The aim of this paper is to analyze the association between the orientation of the aneurysm sac and the clinical and radiological outcomes after surgical clipping. METHODS: Data from 50 MCA bifurcation clipped aneurysms in 47 patients were collected retrospectively. Three different groups were identified according to the aneurysmal sac orientation: anterior-inferior, posterior and superior. A possible association between the aneurysmal sac projection and the outcome was searched through a univariable logistic regression analysis. RESULTS: Statistical analysis showed significant correlation between the radiologic evidence of post-operative ischemia in the posterior group (p = 0.046, RR = 1.65) and an increased risk in the superior orientation group (p = 0.145, RR = 1.38). The anterior-inferior group was, instead, significantly associated with no evidence of radiologic ischemia (p = 0.0019, RR = 0.58). CONCLUSION: The orientation of the aneurysmal dome and sac represents a fundamental feature to be considered during the surgical clipping of the MCA aneurysms. Indeed, its posterior and superior projection is associated with a higher incidence of radiologic ischemic lesions due to the origin of perforating arteries from M1 segment behind the aneurysmal sac. The anterior-inferior orientation, on the contrary, is associated with a lower risk.

Long-term outcomes of endovascular treatment of isolated subclavian artery aneurysms.

OBJECTIVES: The aim of the present study was to review our institutional experience of endovascular treatment for isolated subclavian artery aneurysms and evaluate the long-term outcomes. METHODS: A retrospective review of all patients with isolated subclavian artery aneurysms who underwent endovascular treatment between March 2008 and March 2020 was performed. The demographics, aneurysmal characteristics, treatment strategies, and in-hospital and follow-up outcomes were recorded and then analyzed. RESULTS: From March 2008 to March 2020, 35 isolated subclavian artery aneurysms were endovascularly treated at our institution. Atherosclerosis was the most common cause of aneurysms in this series. Most aneurysms were intrathoracic (91.4%) and located at the right side (77.1%). There were 26 true aneurysms, seven pseudoaneurysms, and two ruptured isolated subclavian artery aneurysms. Five types of endovascular strategies were performed. Covered stent placement across the aneurysm was the most (54.3%) commonly used method. Technical success was achieved in all patients. The median postoperative in-hospital stay was 4.0 days (range, 1-15 days). One patient died after discharge but within 30 days of surgery due to myocardial infarction. The median follow-up time was 62.0 months (range, 3-132 months). No death, stroke, stent fractures, or severe upper limb ischemia developed during the follow-up period. The cumulative survival rate at five years was 97.1%. The overall complication rate was 25.7% and one-third of complications (8.6%) required reinterventions. CONCLUSIONS: Endovascular treatment for isolated subclavian artery aneurysms is safe, effective and technically achievable in most patients. Short- and long-term outcomes are promising. Reasonable and flexible use of covered stents can also get satisfactory outcomes in some complicated lesions such as isolated subclavian artery aneurysms located at the origin of the right subclavian artery, avoiding the huge surgical trauma caused by conventional open repair.

The Woven EndoBridge (WEB) Versus Conventional Coiling for Treatment of Patients with Aneurysmal Subarachnoid Hemorrhage: Propensity Score-Matched Analysis of Clinical and Angiographic Outcome Data.

OBJECTIVE: Conventional coiling is standard for treatment of ruptured intracranial aneurysms. We compared clinical and angiographic outcomes between intrasaccular flow disruption with the Woven EndoBridge (WEB) and conventional coiling in patients with aneurysmal subarachnoid hemorrhage (aSAH) using a propensity score-matched analysis. METHODS: This is a retrospective study of consecutive patients with aSAH treated with the WEB or conventional coiling between 2010 and 2019. Baseline characteristics, procedural complications, angiographic results, and functional outcome were compared between both groups. RESULTS: Fifty-two patients treated with the WEB and 236 patients treated by coiling were included. The WEB group was characterized by a higher patient age (P = 0.024), a wider aneurysm neck (P < 0.001), and more frequent location at the posterior circulation (P = 0.004). Procedural complications were comparable between WEB (19.2%) and coiling (22.7%, P = 0.447). In-hospital mortality rates were higher in the coiling group (WEB: 5.8%, coiling: 17.8%; P = 0.0034). Favorable outcome (modified Rankin scale ≤2) was obtained in 51.3% after WEB embolization and in 55.0% after coiling (P = 0.653). Retreatment was performed in 26.4% of patients after WEB and in 25.8% after coiling (P = 0.935). Propensity score analysis confirmed these results and revealed higher adequate occlusion rates at midterm follow-up for WEB-treated aneurysms (WEB: 93.9%, coiling: 76.2%, P = 0.058). CONCLUSIONS: Compared with conventional coiling, aSAH patients treated with the WEB have a similar clinical and potentially improved angiographic outcome at midterm follow-up. The WEB might be considered as an alternative to conventional coiling for the treatment of RIAs, in particular for those with wide-necked and thus challenging anatomy.

Hemodynamic Force as a Potential Regulator of Inflammation-Mediated Focal Growth of Saccular Aneurysms in a Rat Model.

Past studies have elucidated the crucial role of macrophage-mediated inflammation in the growth of intracranial aneurysms (IAs), but the contributions of hemodynamics are unclear. Considering the size of the arteries, we induced de novo aneurysms at the bifurcations created by end-to-side anastomoses with the bilateral common carotid arteries in rats. Sequential morphological data of induced aneurysms were acquired by magnetic resonance angiography. Computational fluid dynamics analyses and macrophage imaging by ferumoxytol were performed. Using this model, we found that de novo saccular aneurysms with a median size of 3.2 mm were induced in 20/45 (44%) of animals. These aneurysms mimicked human IAs both in morphology and pathology. We detected the focal growth of induced aneurysms between the 10th and 17th day after the anastomosis. The regional maps of hemodynamic parameters demonstrated the area exposed to low wall shear stress (WSS) and high oscillatory shear index (OSI) colocalized with the regions of growth. WSS values were significantly lower in the growing regions than in ones without growth. Macrophage imaging showed colocalization of macrophage infiltration with the growing regions. This experimental model demonstrates the potential contribution of low WSS and high OSI to the macrophage-mediated growth of saccular aneurysms.

Hemodynamics in aneurysm blebs with different wall characteristics.

BACKGROUND: Blebs are important secondary structures of intracranial aneurysms associated with increased rupture risk and can affect local wall stress and hemodynamics. Mechanisms of bleb development and evolution are not clearly understood. We investigate the relationship between blebs with different wall characteristics and local hemodynamics and rupture sites. METHODS: Blebs with different wall appearances in intra-operative videos were analyzed with image-based computational fluid dynamics. Thin red blebs were compared against thick atherosclerotic/hyperplastic white/yellow blebs. Rupture points were identified in videos of ruptured aneurysms harboring blebs. RESULTS: Thin blebs tended to be closer to the inflow than atherosclerotic blebs of the same aneurysm (P=0.0234). Blebs near the inflow had higher velocity (P=0.0213), vorticity (P=0.0057), shear strain rate (P=0.0084), wall shear stress (WSS) (P=0.0085), and WSS gradient (P=0.0151) than blebs far from the inflow. In a subset of 12 ruptured aneurysms harboring blebs, rupture points were associated with thin blebs in 42% of aneurysms, atherosclerotic blebs in 25%, and were away from blebs in the remaining 33%. CONCLUSIONS: Not all blebs are equal; some have thin translucent walls while others have thick atherosclerotic walls. Thin blebs tend to be located closer to the inflow than atherosclerotic blebs. Blebs near the inflow are exposed to stronger flows with higher and spatially variable WSS than blebs far from the inflow which tend to have uniformly lower WSS. Aneurysms can rupture at thin blebs, atherosclerotic blebs, and even away from blebs. Further study of wall failure in aneurysms with different bleb types is needed.

Hemodynamic conditions that favor bleb formation in cerebral aneurysms.

BACKGROUND: Although it is generally believed that blebs represent weaker spots in the walls of intracranial aneurysms (IAs), it is largely unknown which aneurysm characteristics favor their development. OBJECTIVE: To investigate possible associations between aneurysm hemodynamic and geometric characteristics and the development of blebs in intracranial aneurysms. METHODS: A total of 270 IAs in 199 patients selected for surgical clipping were studied. Blebs were visually identified and interactively marked on patient-specific vascular models constructed from presurgical images. Blebs were then deleted from the vascular reconstruction to approximate the aneurysm before bleb formation. Computational fluid dynamics studies were performed in these models and in cases without blebs. Hemodynamic and geometric characteristics of aneurysms with and without blebs were compared. RESULTS: A total of 173 aneurysms had no blebs, while 97 aneurysms had a total of 122 blebs. Aneurysms favoring bleb formation had stronger (p<0.0001) and more concentrated inflow jets (p<0.0001), higher flow velocity (p=0.0061), more complex (p<0.0001) and unstable (p=0.0157) flow patterns, larger maximum wall shear stress (WSS; p<0.0001), more concentrated (p=0.0005) and oscillatory (p=0.0004) WSS distribution, and a more heterogeneous WSS field (p<0.0001), than aneurysms without blebs. They were also larger (p<0.0001), more elongated (p<0.0001), had wider necks (p=0.0002), and more distorted and irregular shapes (p<0.0001). CONCLUSIONS: Strong and concentrated inflow jets, high-speed, complex, and unstable flow patterns, and concentrated, oscillatory, and heterogeneous WSS patterns favor the formation of blebs in IAs. Blebs are more likely to form in large, elongated, and irregularly shaped aneurysms. These adverse characteristics could be considered signs of aneurysm instability when evaluating aneurysms for conservative observation or treatment.

Experience of managing superior mesenteric artery aneurysm and its midterm follow-up results with 18 cases.

OBJECTIVES: To characterize the clinical features, treatment, and prognosis of superior mesenteric artery aneurysms and provide evidence for clinical decision-making. METHODS: We retrospectively reviewed the diagnosis and treatment of 18 cases of superior mesenteric artery aneurysm admitted to our center from 2003 to 2020, including demographic data, risk factors, clinical manifestations, diagnosis, treatment strategies, and follow-up results. RESULTS: The average age of the patients was 49.1 years, and males accounted 83.3%. The development of the disease was associated with infection, hypertension, pancreatitis, and trauma, but no significant associations with atherosclerosis were noted by our results. Nine patients were diagnosed with true aneurysm, seven patients with pseudoaneurysm, and two patients with dissecting aneurysm. Rupture of aneurysm occurred in three patients (16.7%), and one of them died before surgery. The surgery success rate was 94.1%, and open surgery was performed on nine patients, endovascular surgery on three patients, and conservative treatment on three patients. The follow-up rate was 77.8% (14/18), and the average follow-up time was 48.2 months. The mortality and reintervention rate during follow-up was 0. The two-year patency rate of artificial vessels and covered stents was 50%. CONCLUSION: The clinical manifestations and features of superior mesenteric artery aneurysms vary between patients. Careful evaluation of vascular anatomy and personalized treatment strategy are critical in the management of superior mesenteric artery aneurysms. Midterm follow-up results of superior mesenteric artery aneurysms are satisfactory.

Effect of bifurcation in the hemodynamic changes and rupture risk of small intracranial aneurysm.

The role of bifurcations is prominent in the intracranial aneurysm (IA) evaluation, and there are many contradictions and complexities in the rupture risk of small IA. Therefore, in the present study, the effect of bifurcation on the manner of hemodynamic changes and the rupture risk of the small middle cerebral artery (MCA) aneurysm is investigated. 3D anatomical models of the MCAs of 21 healthy subjects, 19 patients/IA/bifurcation, and 19 patients/IA were generated, and the models were analyzed by the computational fluid dynamic (CFD) analysis. The presence of bifurcation in the pathway of the blood flow in the parent artery of healthy subjects has reduced the maximum velocity, flow rate, and wall shear stress (WSS) by 25.8%, 38.6%, and 11.1%, respectively. The bifurcation decreased the maximum velocity and flow rate in the neck and sac of the aneurysm by 1.65~2.1 times, respectively. It increased the maximum WSS, and phase lag between the WSS graph of healthy subjects and patients by 12.8%~13.9% and 10.2%~40.4%, respectively. The effect of bifurcation on the Womersley number change in the aneurysm was insignificant, and the blood flow was in the laminar flow condition in all samples. The results also showed bifurcation increased the phase lag between the flow rate and pressure gradient graphs up to approximately 1.5 times. The rupture prediction index for patients/IA/bifurcation and patients/IA was 62.1%(CV = 4.1) and 51.8%(CV = 4.4), respectively. Thus, in equal conditions, the presence of bifurcation increased the probability of the rupture of the aneurysm by 19.9%.

Association between sleep duration and rupture of intracranial aneurysms: A single-center retrospective study.

OBJECTIVE: To assess the relationship between sleep duration and risk of rupture of intracranial aneurysms (IAs). METHODS: According to our inclusion and exclusion criteria, 683 patients admitted to Beijing Tiantan Hospital were included in this study. There were 201 patients in the ruptured group and 482 patients in the unruptured group. Sleep duration was divided into three levels: ≥8 h (long), 6-8 h (normal), ≤6 h (short). Correlation between different sleep duration and rupture of IAs was evaluated by univariate and multivariate regression analysis. RESULTS: The results of multivariate analysis demonstrated that there was a statistical difference between sleep duration of ≤6 h and sleep duration ≥8 h (OR = 1.76, CI = [1.08-2.87], p = 0.025). There was no statistically significant difference between the group with sleep duration of 6-8 h and sleep duration of ≥8 h (OR = 1.04, CI = [0.65-1.67], p = 0.857). CONCLUSION: Short sleep duration (≤6 h) may be related to the rupture of intracranial aneurysms. The reason for this correlation is not yet clear. We suspect that it may be caused by a series of physiological changes caused by reduced sleep.