Morphological and Hemodynamic Discriminators for Rupture Status in Posterior Communicating Artery Aneurysms

Background and Purpose

The conflicting findings of previous morphological and hemodynamic studies on intracranial aneurysm rupture may be caused by the relatively small sample sizes and the variation in location of the patient-specific aneurysm models. We aimed to determine the discriminators for aneurysm rupture status by focusing on only posterior communicating artery (PCoA) aneurysms.

Materials and Methods

In 129 PCoA aneurysms (85 ruptured, 44 unruptured), clinical, morphological and hemodynamic characteristics were compared between the ruptured and unruptured cases. Multivariate logistic regression analysis was performed to determine the discriminators for rupture status of PCoA aneurysms.

Results

While univariate analyses showed that the size of aneurysm dome, aspect ratio (AR), size ratio (SR), dome-to-neck ratio (DN), inflow angle (IA), normalized wall shear stress (NWSS) and percentage of low wall shear stress area (LSA) were significantly associated with PCoA aneurysm rupture status. With multivariate analyses, significance was only retained for higher IA (OR = 1.539, p < 0.001) and LSA (OR = 1.393, p = 0.041).

Conclusions

Hemodynamics and morphology were related to rupture status of intracranial aneurysms. Higher IA and LSA were identified as discriminators for rupture status of PCoA aneurysms.     

Morphological Parameters Associated with Ruptured Posterior Communicating Aneurysms

The rupture risk of unruptured intracranial aneurysms is known to be dependent on the size of the aneurysm. However, the association of morphological characteristics with ruptured aneurysms has not been established in a systematic and location specific manner for the most common aneurysm locations. We evaluated posterior communicating artery (PCoA) aneurysms for morphological parameters associated with aneurysm rupture in that location. CT angiograms were evaluated to generate 3-D models of the aneurysms and surrounding vasculature. Univariate and multivariate analyses were performed to evaluate morphological parameters including aneurysm volume, aspect ratio, size ratio, distance to ICA bifurcation, aneurysm angle, vessel angles, flow angles, and vessel-to-vessel angles. From 2005–2012, 148 PCoA aneurysms were treated in a single institution. Preoperative CTAs from 63 patients (40 ruptured, 23 unruptured) were available and analyzed. Multivariate logistic regression revealed that smaller volume (p = 0.011), larger aneurysm neck diameter (0.048), and shorter ICA bifurcation to aneurysm distance (p = 0.005) were the most strongly associated with aneurysm rupture after adjusting for all other clinical and morphological variables. Multivariate subgroup analysis for patients with visualized PCoA demonstrated that larger neck diameter (p = 0.018) and shorter ICA bifurcation to aneurysm distance (p = 0.011) were significantly associated with rupture. Intracerebral hemorrhage was associated with smaller volume, larger maximum height, and smaller aneurysm angle, in addition to lateral projection, male sex, and lack of hypertension. We found that shorter ICA bifurcation to aneurysm distance is significantly associated with PCoA aneurysm rupture. This is a new physically intuitive parameter that can be measured easily and therefore be readily applied in clinical practice to aid in the evaluation of patients with PCoA aneurysms.     

前交通动脉复合体的显微外科解剖研究

目的:通过手术显微镜对前交通动脉复合体及穿支进行解剖和测量,进一步熟悉和掌握该复合体的结构及毗邻血管的走行,为前交通动脉瘤手术提供解剖学依据.方法:用红色乳胶经颈内动脉对15例(30侧)福尔马林固定的湿性尸头进行灌注,然后在手术显微镜下对前交通动脉复合体进行解剖观测,所得结果用SPSS17.0软件进行统计分析.测量大脑前动脉A1和A2段、前交通动脉、Heubner回返动脉、A1段和前交通动脉穿支的长度、直径和各种形态变异.结果:未经选择的标本双侧A1发育无明显差异;术中对Heubner回返动脉、A1段穿支、前交通动脉穿支应仔细分辨加以保护;A1中1/3段穿支少,可作为前交通动脉瘤手术时临时阻断A1的部位;血管造影时前交通动脉不易看清与多种因素有关.结论:前交通动脉复合体复杂多变,熟悉前交通动脉复合体及穿支的解剖特点,对外科医生处理该区疾病至关重要.

Abstract：

Objective:To investigate the anatomy structure and adjacent vessels by investigating the anterior communicating artery complex and its perforating branches under an surgery microscope, in order to, to provide anatomical datas for anterior communicating aneurysms. Method: A total of 15 adult cadaveric heads (30 cerebral hemispheres) fixed with formalin were used, red latex was injected into internal carotid artery. Anterior communicating artery complexes were dissected, detected by surgery microscope.The results were analyzed with SPSS 17.0 statistical software. The lengthes, diameters and variations of the anterior cerebral artery(ACA)A 1 segment, A2 segment, anterior communicating artery (AComA), Heubner recurrent artery(HRA), perforating branches of A1 segment and AcomA were measured. Result:There were no statistically significant differences between two sides of A1 segment in length and diameter. HRA, perforating branches of Al segment and AComA should be carefully recognized and protected during the operation on anterior communicating aneurysms. The middle 1/3 of A1 segment which had less perforating branches was the best position for temporary occlusion during the operation on anterior communicating aneurysms. It is difficult to distinguish AComA in cerebral angiography. Conclusion: The anterior communicating artery complex was regarded as the most complex. Being familiar with the anatomy of the anterior communicating artery complex and the perforating branches enabled neurosurgeons to handle the diseases in this area efficiently.     

Posterior Cerebral Artery Angle and the Rupture of Basilar Tip Aneurysms

Since the initial publication of the International Study of Unruptured Intracranial Aneurysms (ISUIA), management of unruptured intracranial aneurysms has been mainly based on the size of the aneurysm. The contribution of morphological characteristics to treatment decisions of unruptured aneurysms has not been well studied in a systematic and location specific manner. We present a large sample of basilar artery tip aneurysms (BTA) that were assessed using a diverse array of morphological variables to determine the parameters associated with ruptured aneurysms. Demographic and clinical risk factors of aneurysm rupture were obtained from chart review. CT angiograms (CTA) were evaluated with Slicer, an open source visualization and image analysis software, to generate 3-D models of the aneurysms and surrounding vascular architecture. Morphological parameters examined in each model included aneurysm volume, aspect ratio, size ratio, aneurysm angle, basilar vessel angle, basilar flow angle, and vessel to vessel angles. Univariate and multivariate analyses were performed to determine statistical significance. From 2008–2013, 54 patients with BTA aneurysms were evaluated in a single institution, and CTAs from 33 patients (15 ruptured, 18 unruptured) were available and analyzed. Aneurysms that underwent reoperation, that were associated with arteriovenous malformations, or that lacked preoperative CTA were excluded. Multivariate logistic regression revealed that a larger angle between the posterior cerebral arteries (P1-P1 angle, p = 0.037) was most strongly associated with aneurysm rupture after adjusting for other morphological variables. In this location specific study of BTA aneurysms, the larger the angle formed between posterior cerebral arteries was found to be a new morphological parameter significantly associated with ruptured BTA aneurysms. This is a physically intuitive parameter that can be measured easily and readily applied in the clinical setting.     

Histological Analysis of Extracranial Carotid Artery Aneurysms

Introduction

Extracranial carotid artery aneurysms (ECAA) are rare but may be accompanied with significant morbidity. Previous studies mostly focused on diagnostic imaging and treatment. In contrast, the pathophysiological mechanisms and natural course of ECAA are largely unknown. Understanding the pathophysiological background may add to prediction of risk for adverse outcome and need for surgical exclusion. The aim of this study was to investigate the histopathological characteristics of ECAA in patients who underwent complete surgical ECAA resection.

Material and Methods

From March 2004 till June 2013, 13 patients were treated with open ECAA repair. During surgery the aneurysm sac was resected and processed for standardized histological analysis. Sections were stained with routine hematoxylin and eosin and special stains to detect elastin, collagen, different types of inflammatory cells, vascular smooth muscle cells and endothelial cells.

Results

Histopathological characterization revealed two distinct categories: dissection (abrupt interruption of the media; n = 3) and degeneration (general loss of elastin fibers in the media; n = 10). In the degenerative samples the elastin fibers in the media were fragmented and were partly absent. Inflammatory cells were observed in the vessel wall of the aneurysms.

Conclusion

Histological analysis in this small sample size revealed dissection and degeneration as the two distinct underlying mechanisms in ECAA formation.     

Correlation Between the Rupture Risk and 3D Geometric Parameters of Saccular Intracranial Aneurysms

The purpose of this study is to evaluate the association of the location and geometric parameters of intracranial aneurysm with the risk of rupture. A retrospective study consisted of 284 patients diagnosed with saccular intracranial aneurysm between January 2009 and May 2013 at Wuxi Third People’s Hospital was conducted. 3D digital subtraction angiography images from all patients (240 ruptured, 44 unruptured) were obtained and analyzed. The location of the aneurysms and the 3D geometric parameters including the aneurysm depth, the neck size, diameter of the parent artery, aneurysm angle, aspect radio, size ratio, and the neck-to-parent-artery ratio (NPR) were compared between ruptured and unruptured groups. Results: In ruptured group, anterior communicating artery, posterior communicating artery (PCoA), and the bifurcation of internal carotid artery (ICA) were the top three locations for aneurysm occurrence, accounting for 40.00, 30.42, and 12.08 % respectively. While in the unruptured group, top three locations were PCoA (36.36 %), posterior cerebral circulation (18.18 %), and the bifurcation of the ICA (15.91 %). Distribution of aneurysm location is significantly different (p < 0.05) between ruptured and unruptured aneurysms. For the 3D geometric parameters characterizing aneurysm, aneurysm depth (p < 0.05), parent artery diameter (p < 0.05), aneurysm angle (p < 0.01), aspect ratio (p < 0.01), and size ratio (p < 0.01) all showed a significant difference between ruptured and unruptured group. No difference was found in the neck size and the NPR ratio between the two groups. 3D geometric parameters such as aneurysm depth, parent artery diameter, aneurysm angle, aspect ratio, and size ratio can be helpful in evaluating the rupture risk of saccular intracranial aneurysm for a better prevention and prognosis.     

血管内栓塞治疗已破裂后交通动脉瘤的临床研究

目的:探讨已破裂后交通动脉瘤的血管内栓塞介入治疗的临床疗效.方法:对73例血管内介入栓塞治疗已破裂后交通动脉瘤患者资料回顾分析,观察临床治疗效果.结果:所有患者均成功栓塞,获100％栓塞35个(47.9％),95％栓塞24个(32.9％),90％栓塞13个(17.8％),80％栓塞1个(1.4％),发生并发症6例(8.2％),术后随访未见复发病例(0.0％).结论:已破裂后交通动脉的血管内介入栓塞治疗是一种微创、安全、有效的方法.     

显微外科手术治疗破裂前循环脑动脉瘤的临床研究

目的:旨在进一步提高手术治疗破裂的前循环脑动脉瘤的效果.方法:回顾性分析显微手术治疗的56例破裂前循环脑动脉瘤患者的临床资料.结果:56例病人,共61个脑动脉瘤,其中45枚行动脉瘤颈夹闭,6枚夹闭瘤颈后切除瘤体,另10枚动脉瘤予以瘤壁包裹加固术.术后第3天发生血管闭塞1例,遗留肢体偏瘫.25例随访1个月～5年,恢复良好17例,中残或重残2例,死亡2例.结论:显微手术治疗破裂的脑动脉瘤,不仅有效地防止再出血,而且有利于脑血管痉挛的防治.术后扩充血容量,提升血压,扩张血管对防治脑血管痉挛具有相当好的疗效.     

诱导MSCs向成骨细胞分化相关因素研究现状

骨髓间充质干细胞(mesenchymal steml cells,MSCs)是干细胞家族的重要成员,是一类具有自我增殖和多项分化潜能的多能干细胞.MSCs定向分化为成骨细胞将可能为包括骨缺损、骨折不愈合、股骨头坏死等多种骨科难治性疾病的治疗带来一场革新.本文主要介绍了化学因素、生物因素、他汀类药物、物理因素、转基因技术以及中医药等相关因素诱导MSCs向成骨细胞分化的研究现状.     

颅内动脉瘤栓塞术的临床分析

目的：用动脉瘤栓塞体积比评价颅内动脉瘤栓基术的治疗效果,观察颅内动脉瘤栓塞术治疗颅内动脉瘤的影响因素及颅内动脉瘤栓塞术的术后情况。方法：选取112例行血管内栓塞治疗的患者为研究对象,按术后动脉瘤栓塞体积比分成VER〉25％和VER〈25％两组,观察不同的栓塞材料（电解可脱弹簧圈、水解可脱弹簧圈）和术中血管的痉挛程度（轻、中、重）对栓塞程度的影响;术后随访106例病人,按动脉瘤栓塞体积比分成VER〉25％和VER〈25％两组,统计两组患者的再出血率和复发率,用动脉瘤栓塞体积比评价栓塞术的预后效果。结果：动脉瘤栓塞体积比VER〉25％和VER〈25％两组间进行比较,不同血管痉挛情况下和使用不同的栓塞材料在两组间均存在显著差异（P〈O．05）,具有统计学意义;术后随访半年,比较VER〉25％和VER〈25％两组的再出血率也有显著差异（P〈O．05）,具有统计学意义。结论：动脉瘤栓塞体积比在评价颅内动脉瘤栓塞术中有重要意义,血管痉挛情况、栓塞材料是影响颅内动脉瘤栓塞术栓塞疗效的主要影响因素;术后随访证实动脉瘤栓塞体积比对评价动脉瘤栓塞术的预后有一定的作用。