Anatomical Features of Abdominal Aortic Aneurysm on CT Angiography: A Comparison Study

Background: There is little information about the anatomical characteristics and relationship between ruptured and unruptured abdominal aortic aneurysm (AAA). Objective: The present study was to determine the anatomical differences between the two groups as assessed with multi-detector computed tomographic angiography (CTA). Materials and Methods: A retrospective review of all the patients diagnosed with AAA that underwent CTA before aortic repair were performed with matching between ruptured and unruptured groups for age and gender. Patient characteristics, and morphological data of aneurysmal and non-aneurysmal parts on CTA images were reviewed. Results: Ninety-six patients in each group were matched. The ruptured group had significantly lower systolic blood pressure (p=0.027), and higher blood creatinine (p=0.006). In the aneurysm part, maximal aneurysmal diameter was significantly larger in the ruptured group at 7.8 cm versus 6 cm (p<0.001), as well as the larger lumen diameter (p=0.006), longer aneurysmal length (p=0.005), shorter aneurysmal neck length (p=0.009), and thicker maximal thrombus thickness (p<0.001). In the non-aneurysmal part, the aortic diameter of the ruptured group was significantly larger in every location. Multivariate analysis indicated that maximal aneurysmal diameter, non-aneurysmal part of the infrarenal aortic diameter, aneurysmal neck length, and current smoking status remained significant variables for ruptured AAAs. Conclusion: Ruptured AAAs had shorter aneurysmal neck length and larger diameter of both aneurysmal and non-aneurysmal parts of AAA than unruptured group. Keywords: Abdominal aortic aneurysm; CT angiography

Value of 3D-DSA in the detection of intracranial aneurysms

Aim: To determine the value of three-dimensional (3D) digital subtraction angiography (DSA) in the detection of intracranial aneurysms and to compare 3D technique with DSA. Materials and Methods: A retrospective analysis of 50 patients with 60 intracranial aneurysms who underwent both conventional DSA and 3D-DSA for the evaluation of intracranial aneurysms was conducted. The presence of aneurysms, detection of aneurysmal neck, size, location, presence of additional and small aneurysms analyzed from the two protocols were compared. Results: Three-dimensional technique detected 54 aneurysms while conventional DSA detected 38 aneurysms. There was no correlation between aneurysm detection and aneurysm neck detection in the two technologies observed, but there was a difference in detection performance depending on the technology used. Three-dimensional technique detected 52 aneurysm necks while conventional DSA detected 24 aneurysm necks. There was a statistically significant and positive relationship between the detected size of the aneurysm using 3D technique and DSA technology. Three-dimensional technique detected 24 additional aneurysms while conventional DSA detected only six additional aneurysms. Conclusions: Three-dimensional technique are more successful in the detection of aneurysms, their necks and small aneurysms in comparison to digital subtraction angiography, but difference is not statistically significant. The size of the aneurysm statistically significant affects the aneurysm neck detection by conventional DSA.

Nautilus-assisted coil embolization for a complex AcomA wide-necked aneurysm in the setting of acute subarachnoid hemorrhage

Numerous devices and sophisticated strategies have been developed to further increase the number of aneurysms amenable to endovascular treatment.1–4 Despite the superfluity of available neurovascular armamentarium, wide-necked bifurcation aneurysms can still pose a significant technical challenge to the treating clinician.5–7 Neck bridging is a conceptually new approach, which provides increased occlusion rates with lower recurrence and complications rates.8–10 The Nautilus (EndoStream Medical) is an intrasaccular bridging device intended to assist in coil embolization of wide-necked cerebral aneurysms. This CE-marked device, available in various sizes, consists of flexible-layers, and is a nitinol-based, detachable implant. The device is delivered through a standard microcatheter with a minimal 0.0165" inner diameter and is fully radiopaque and completely resheathable.Owing to its unique ‘tornado’ like shape the device entirely reconstructs the aneurysmal neck, which facilitates the following coil embolization. In this video 1, we demonstrate the use of Nautilus - assisted coil embolization for a complex anterior communicating artery (AcomA) wide-necked aneurysm in the setting of acute subarachnoid hemorrhage.Video 1

Guidewires as Embolic Agents? Embolotherapy of Large Splenic Artery Aneurysms

Splenic artery aneurysms are among the more frequently diagnosed intra-abdominal aneurysms and are not infrequent in patients with raised portal venous pressure often requiring endovascular or surgical therapy. A 36-year-old female patient with Non-cirrhotic portal fibrosis and portal hypertension was diagnosed with multiple large splenic artery aneurysms for which she was initially operated which resulted in substantial blood loss during dissection that required embolotherapy. Initial attempts at coil embolization proved unsuccessful due to the wide aneurysmal neck and flow characteristics. Following which the aneurysmal sac was packed with multiple guidewires to act as a scaffold for further coil embolization. Subsequently, hemostasis was achieved and the patient underwent splenectomy later thereby demonstrating that embolization of large aneurysms can be accomplished with reasonable efficacy using guidewires.

The Polymer-Based Technology in the Endovascular Treatment of Abdominal Aortic Aneurysms

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta that progressively grows until it ruptures. Treatment is typically recommended when the diameter is more than 5 cm. The EVAR (Endovascular aneurysm repair) is a minimally invasive procedure that involves the placement of an expandable stent graft within the aorta to treat aortic disease without operating directly on the aorta. For years, stent grafts’ essential design was based on metallic stent frames to support the fabric. More recently, a polymer-based technology has been proposed as an alternative method to seal AAA. This review underlines the two platforms that are based on a polymer technology: (1) the polymer-filled endobags, also known as Endovascular Aneurysm Sealing (EVAS) with Nellix stent graft; and (2) the O-ring EVAR polymer-based proximal neck sealing device, also known as an Ovation stent graft. Polymer characteristics for this particular aim, clinical applications, and durability results are hereby summarized and commented critically. The technique of inflating endobags filled with polymer to exclude the aneurysmal sac was not successful due to the lack of an adequate proximal fixation. The platform that used polymer to create a circumferential sealing of the aneurysmal neck has proven safe and effective.

Visual complications after coil embolization of internal carotid artery aneurysms at the ophthalmic segment

Background Coil embolization of aneurysms of the ophthalmic segment of the internal carotid artery (ICA-OphA ANs) has potential risks of visual complications. We analyzed this risk and focused on the relationship of the ophthalmic artery (OphA) origin with the aneurysm neck. Methods From January 2003 to April 2018, 179 unruptured ICA-OphA ANs were treated with endovascular surgery in our institution. Two ruptured and four aneurysms with missing data were excluded. Finally, 173 unruptured aneurysms were included in this study. The aneurysms were classified into three groups according to the location of the OphA origin: Separate, Shared, and Dome type. We retrospectively assessed visual complications based on the relationship between types of aneurysm and postoperative angiographic findings for the OphA. Results Visual deficits remained permanent in eleven cases (6.4%). In the Dome type, visual complications were significantly more frequent compared to the Separate type. Change in the OphA flow was significantly associated with a higher complication rate of 2.9%, but patients with changed OphA flow had a significant rate of 7.5% ( p = 0.020). We found no significant difference in the incidence of visual complications concerning the use of perioperative antithrombotic therapy. Conclusions The location of OphA origin regarding the aneurysmal neck and postoperative OphA flow were significantly correlated with the visual outcome after coil embolization for ICA-OphA ANs. Post-procedural flow in the OphA was an important factor affecting the rate of ischemic retinal complications. Retinal embolic events occurred with preserved flow in the OphA, albeit at a lower rate.

Delayed Proximal Flow Diverting Stent Migration in a Ruptured Intracranial Aneurysm: A Case Report

A flow diverter can be used to treat a ruptured aneurysm, especially during complicated cases for endovascular or open microsurgical procedures. However, some complications have been reported such as occlusion of side branches or perforating arteries, stent migration or improper stent position, re-rupture of the aneurysm, and in-stent thrombosis. A 38-year-old man diagnosed with a ruptured left supraclinoid aneurysm was treated with a Pipeline embolization device. Despite adequate stent coverage of the aneurysmal neck, delayed proximal migration was seen in follow-up imaging. To our knowledge, proximal migration of the stent mostly happens intraoperatively due to an undersized stent or excessive stretching. We report a case of delayed proximal flow diverter stent migration.

Mechanical thrombectomy for occlusion near a ruptured intracranial aneurysm: A case report

Background: While recent randomized clinical trials have shown the efficacy of mechanical thrombectomy for acute large vessel anterior cerebral occlusion, cases in patients with a subarachnoid hemorrhage (SAH) were excluded from the study. Case Description: A 58-year-old man presented with a SAH as a result of a ruptured middle cerebral artery aneurysm. Coil embolization was performed, and a right intracranial angiography showed remnants of an aneurysmal neck. However, the following angiography also revealed a thromboembolic complication that occurred in the same territory as the ruptured aneurysm. The patient underwent a rescue mechanical thrombectomy under the working projection. We deployed a retrieval stent without covering the aneurysmal neck. The occluded vessel was recanalized without any hemorrhagic complication. Due to minimal intracerebral infarction, the patient had good outcomes. Conclusion: Mechanical thrombectomy is a useful option to retrieve a clot from an occluded intracranial vessel located near a ruptured aneurysm. Approaching the clot at the working projection is important to ensure safety in the setting of a ruptured aneurysm.

The Cascade device – In vitro tests to assess coil protrusion into the parent vessel

Background Balloon and stent-assisted coiling of aneurysms have increased the number of aneurysms available for endovascular treatment. Newer devices that allow flow within the parent vessel but coverage at the neck have recently entered the market. The Cascade is a new non-occlusive fully retrievable neck-bridging support device that has been designed to provide temporary support during coil embolisation of intracranial aneurysms. Methods Using a silicone aneurysm model three different aneurysms were catheterised with the coiling microcatheter placed in three different positions within each aneurysm – at the neck, centrally, and looped within the aneurysm. Multiple different coils were then deployed within each aneurysm with the Cascade device deployed across the neck to provide protection. In total 480 attempted coilings were performed. Aneurysm flow was used to calculate the change in intra-aneurysmal flow with the Cascade device deployed across the neck of the aneurysm. Results We did not observe a single episode of coil protrusion through the Cascade mesh nor did we observe any coil protrusion into the parent vessel when the Cascade was deployed across the neck. There was an average flow velocity reduction of 23% with the Cascade device deployed across the neck of the aneurysm. Conclusion The Cascade device offers robust protection of the aneurysmal neck and parent vessel as well as inducing significant intra-aneurysmal flow velocity reduction.

Prediction of the difficulty of proximal vascular control using 3D-CTA for the surgical clipping of internal carotid artery–posterior communicating artery aneurysms

OBJECTIVEDuring surgical clipping of internal carotid artery (ICA)–posterior communicating artery (PCoA) aneurysms, proximal vascular control (PVC) is difficult to achieve in some cases because of variations in the anatomy of this type of aneurysm and its parent arteries. The authors investigated morphometric features that may be predictive for the necessity of anterior clinoidectomy (ACL) or cervical ICA exposure for PVC.METHODSThe authors retrospectively reviewed 65 patients with an ICA-PCoA aneurysm treated with clipping during the previous 3 years. The factors considered for assessing the difficulty of attaining PVC included the following: the maximum diameter of the aneurysm; the distance between the tip of the anterior clinoid process (ACP) and the proximal aneurysmal neck; the presence of calcification at the ophthalmic segment of the ICA; and the angles between the communicating segment of the ICA and the ophthalmic segment of the ICA and a line perpendicular to the cranial base, which reflect the tortuosity of the ICA. These parameters were measured based on preoperative CTA results.RESULTSIn a total of 21 patients (32.3%), PVC was difficult to perform with the usual pterional approach. In 6 patients, temporary artery occlusions (TAOs) were difficult to achieve because of severe atherosclerotic wall changes in the ophthalmic segment of the ICA. For 15 patients, the ACPs overhanging the ophthalmic segment of the ICA obstructed the ability to secure a space for TAO. In the 21 patients with PVC difficulty, ACL alone, cervical ICA exposure alone, and both ACL and cervical ICA exposure were conducted in 6, 8, and 7 patients, respectively. Multivariate analysis with binary logistic regression revealed that the maximum diameter of the aneurysm (p = 0.041), the distance between the proximal neck of the aneurysm and the ACP tip (p = 0.002), and calcification of the ICA ophthalmic segment (p = 0.001) were significant predictive factors for difficulties with PVC. A receiver operating characteristic curve analysis revealed that a distance between the proximal aneurysmal neck and the ACP tip of ≤ 5.4 mm was the best cutoff value for predicting the difficulty of attaining PVC (area under the curve 0.800, sensitivity 80.0%, specificity 80.0%).CONCLUSIONSA short distance between the proximal aneurysmal neck and the ACP tip and the presence of calcification at the ophthalmic segment of the ICA on preoperative CTA are helpful for predicting the difficulty of achieving PVC.