Computer simulation and analysis of hemodynamic changes in abdominal aortic aneurysms treated with fenestrated endovascular grafts

The purpose of this study was to perform a simulation of blood flow and analyze the hemodynamic changes in patients with abdominal aortic aneurysms (AAA) treated with fenestrated stent grafts. Four patients with AAA undergoing multislice computed tomography angiography pre-and post-fenestrated stent graft implantation were selected for inclusion in the study. Geometric models and hexahedral volume meshes were successfully generated for pre- and post-stent fenestrated implantation. The blood flow pattern was simulated inside the abdominal aortic aneurysm and arterial branches, as well as with a stentgraft in situ. Flow visualization showed that flow disturbances inside the aneurysm were apparently decreased and flow rate was not affected significantly at the renal arteries after deployment of the fenestrated stents into these branches. The wall pressure was found to reduce inside the aneurysm sac following implantation of stent grafts. In this preliminary study, we successfully simulated the flow characteristics in abdominal aortic aneurysm before and after fenestrated endovascular repair

Fenestrated Stent Graft Repair of Abdominal Aortic Aneurysm: Hemodynamic Analysis of the Effect of Fenestrated Stents on the Renal Arteries

Objective: We wanted to investigate the hemodynamic effect of fenestrated stents on the renal arteries with using a fluid structure interaction method. Materials and Methods: Two representative patients who each had abdominal aortic aneurysm that was treated with fenestrated stent grafts were selected for the study. 3D realistic aorta models for the main artery branches and aneurysm were generated based on the multislice CT scans from two patients with different aortic geometries. The simulated fenestrated stents were designed and modelled based on the 3D intraluminal appearance, and these were placed inside the renal artery with an intra-aortic protrusion of 5.0-7.0 mm to reflect the actual patients' treatment. The stent wire thickness was simulated with a diameter of 0.4 mm and hemodynamic analysis was performed at different cardiac cycles. Results: Our results showed that the effect of the fenestrated stent wires on the renal blood flow was minimal because the flow velocity was not significantly affected when compared to that calculated at pre-stent graft implantation, and this was despite the presence of recirculation patterns at the proximal part of the renal arteries. The wall pressure was found to be significantly decreased after fenestration, yet no significant change of the wall shear stress was noticed at post-fenestration, although the wall shear stress was shown to decrease slightly at the proximal aneurysm necks. Conclusion: Our analysis demonstrates that the hemodynamic effect of fenestrated renal stents on the renal arteries is insignificant. Further studies are needed to investigate the effect of different lengths of stent protrusion with variable stent thicknesses on the renal blood flow, and this is valuable for understanding the long-term outcomes of fenestrated repair

Pericardial biopsy and fenestration

Employing a video thoracoscopic pericardial fenestration constitutes a promising technique for the investigation and treatment of chronic pericardial effusions. It combines the benefit of low invasiveness with the advantages of open biopsy. The procedure simultaneously allows both an accurate diagnosis under visual control (inspection, aspiration, well targeted biopsy of pathological processes) and the performance of effective therapeutic intervention. Without imposing unacceptable stress, it also facilitates rapid symptom relief in patients with advanced malignant disease whose general condition is severely impaire

The use of dynamic volumetric CT angiography (DV-CTA) for the characterization of endoleaks following fenestrated endovascular aortic aneurysm repair (f-EVAR)

Accurate endoleak classification is essential following fenestrated endovascular aneurysm repair (f-EVAR). Both endoleak type and exact source of endoleak have implications upon the urgency and complexity of future management strategies. Herein we report on a patient with a documented endoleak post-f-EVAR, in which the source of blood flow into the aneurysm sac could not be determined using conventional computed tomographic angiography. Consequently, dynamic volumetric computed tomographic angiography (DV-CTA) was employed, which clearly illustrated the site of origin of the endoleak. DV-CTA enables accurate endoleak characterization following f-EVAR, with excellent conspicuity of the source of blood flow into the aneurysm sac

Early report from an investigator-initiated investigational device exemption clinical trial on physician-modified endovascular grafts

ObjectiveTo determine whether a physician-modified endovascular graft (PMEG) is a safe and effective method for treating patients with juxtarenal aortic aneurysms who are deemed unsuitable for open repair.MethodsA nonrandomized, prospective, consecutively enrolling investigational device exemption clinical trial was used. Data collected on patients treated with PMEG between April 2011 and August 2012 were analyzed. Subjects were followed with computed tomography, visceral duplex, and four-view X-ray at 30 days, 6 months, and 1 year. The protocol was designed to include follow-up to 5 years. The primary safety end point was the proportion of subjects who experienced a major adverse event (MAE) within 30 days of the procedure. The primary efficacy end point was the proportion of subjects experiencing treatment success.ResultsDuring the 16-month study period, 28 patients were consented and 26 underwent endovascular repair using PMEGs. Anatomic, operative details, and length of stay were recorded and included aneurysm diameter (mean, 62.5 mm), proximal neck length (mean, 4.4 mm), graft manufacture time (mean, 59.7 minutes), procedure time (mean, 169 minutes), fluoroscopy time (mean, 42.8 minutes), total contrast usage (mean, 63 mL), estimated blood loss (mean, 221 mL), and length of hospital stay (mean, 4.9 days). There were 63 fenestrations created for 48 renal arteries and 15 superior mesenteric arteries. Renal artery fenestrations were stented whenever possible (96%) and superior mesenteric artery fenestrations were all left unstented. There were no unanticipated adverse device events, no MAEs, and only a single minor adverse device event treated with a successful reintervention. At 30 days, there were no type I or III endoleaks and only four type II endoleaks (15.4%). Two patients died during the study period, one at day 23 from respiratory failure (in-hospital and 30-day mortality = 3.8%) and one at day 210 from urosepsis and congestive heart failure. MAEs occurred in 11.5% of patients at 30 days. The primary efficacy end point was achieved in 87.5% of patients (technical success 100%, freedom from migration, rupture or conversion, type I or III endoleaks, or sac enlargement = 100%, 100%, 87.5%, and 87.5%, respectively).ConclusionsThese preliminary data suggest that endovascular repair with PMEG is safe and effective for managing patients with juxtarenal aortic aneurysms. Endovascular repair with PMEG has acceptable early rates of morbidity, mortality, and endoleak. This endovascular aortic strategy is particularly appealing for those patients presenting with symptomatic or ruptured aortic aneurysms until reliable off-the-shelf solutions become widely available

Paraplegia induced by mild trauma in a child with thoracic spinal arachnoid cyst

AbstractSpinal arachnoid cysts are rare entities that often present with progressive myelopathy and are treated via surgical excision and fenestration. The acute onset of symptoms from these lesions is not well described in the literature. We report an 18-month-old child with acute onset of paraplegia following a mild trauma, who was found to have a compressive dorsal thoracic intradural spinal arachnoid cyst and emergently treated via surgical decompression and cyst resection. After several months of physical therapy the child achieved meaningful neurologic recovery. Spinal arachnoid cysts can cause acute decompensation in children with serious neurological injury following mild trauma, this risk should be weighed when managing asymptomatic lesions

An Adjuvant Technique in Endovascular Treatment of Post-Dissection Thoraco-Abdominal Aortic Aneurysms

Introduction: In chronic aortic dissection complicated by aneurysmal degeneration, the absence of spontaneous tears between the true and false lumen at visceral artery level may limit treatment by fenestrated/branched endovascular aneurysm repair (F/BEVAR). The creation of new fenestrations may be required to allow access to the visceral vessels. Technique: In this video, the endovascular treatment of a 70 year old white man with chronic type B aortic dissection complicated by Crawford type II thoraco-abdominal aortic aneurysmal degeneration is presented. The right renal artery had a false lumen origin without nearby visible re-entry tears. He underwent dissection flap fenestration at visceral vessel level using a transjugular intrahepatic portosystemic shunt (TIPS) needle and subsequent dilation with a high pressure balloon. A Zenith TX2 dissection endovascular graft was deployed proximally and extended distally with a Zenith dissection endovascular stent until the fenestration level was reached. In a second stage, a F/BEVAR was performed, with fenestration to the left renal artery and branches to right renal artery, superior mesenteric artery, and coeliac trunk. One year follow up computed tomography angiography showed visceral branch patency and a reduction of the aneurysm sac. Discussion: The chronic dissection flap may be thick and fibrotic, creating a technical challenge for endovascular fenestration. The off label use of a TIPS needle in this procedure created a new fenestration at the desired level and allowed definitive post-dissection treatment of the thoraco-abdominal aneurysm.publishersversionpublishe