Infrarenal Aortic Aneurysm Research Articles

Directional Control for Precise Deployment of Endovascular Aneurysm Repair and Thoracic Endovascular Aortic Repair in Angulated Anatomy

Endovascular stent graft repair of aortic aneurysms has become the standard in most centers. Several anatomic constraints still prevent or compromise the use of this technology. Angulated infrarenal aortic necks or steep aortic arches may result in erratic stent graft deployment with inadvertent branch vessel coverage, inadequate lesion coverage, or bird beaking. We have developed a technique using off-the-shelf equipment to precisely control the deployment of stent grafts in challenging landing zones. Two patients with challenging proximal landing zones were treated by this technique. The first patient, a 72-year-old man, was treated with a Gore Excluder device (W. L. Gore & Associates, Flagstaff, Ariz) for a 5.6-cm infrarenal aortic aneurysm with an angulated neck. A standard J wire was passed through the device, captured with an endosnare, and removed through a Destino sheath (Oscor, Palm Harbor, Fla) in the contralateral groin. The through-and-through wire and sheath allowed the precise deflection of the device along the angulated neck. The device was deployed while deflected. The remainder of the case was unremarkable. The second patient was an 84-year-old man who developed a descending thoracic aortic intramural hematoma with acute enlargement and pseudoaneurysm in the setting of type III aortic arch. In the operating room, two GORE CTAG thoracic stent grafts were built up from the celiac into the proximal descending thoracic aorta. A final proximal stent graft was advanced into approximate position. Left brachial access was established, and a J wire was brought through and through from the stent graft into a 5F MPA catheter in the left brachial sheath. Through a combination of wire traction and forward force on the MPA catheter, the device was precisely positioned onto the lesser curve. The graft was deployed orthogonally at the level of the left carotid. A left subclavian snorkel was planned preoperatively and was placed. In both cases, technical success was attained. Follow-up imaging at 6 weeks in each case demonstrated continuous wall apposition and no endoleak. Anatomic constraints have limited or complicated the use of endovascular stent grafts for some aortic disease. The use of a through-and-through flexible wire and a stiff catheter or sheath allows precise placement in these challenging landing zones.

Sonographic Changes in Optic Nerve Sheath Diameter Associated with Supra- versus Infrarenal Aortic Aneurysm Repair.

Quantification of changes in optic nerve sheath diameter (ONSD) using ocular sonography (OS) constitutes an elegant technique for estimating intracranial and intraspinal pressure. Aortic aneurysm repair (AAR) is associated with a reasonable risk of increased spinal fluid pressure, which is largely dependent on the extent of aneurysm repair (supra- vs. infrarenal). The aim of this study was to compare ONSD measurements in patients with suprarenal AAR (sAAR) or infrarenal AAR (iAAR). Thirty patients who underwent elective endovascular repair of infrarenal aortic aneurysms (Group iAAR) were included in the study; the characteristics in these cases were prospectively analyzed and compared with those in a previously investigated group of 28 patients treated for suprarenal aortic aneurysms (Group sAAR). Six measurements of ONSDs were performed in each patient at five consecutive time points. Statistical analysis was performed using the Wilcoxon test. A P value < .05 was considered statistically significant. A highly significant difference between pre- and postinterventional values could be detected in both patient groups (P < .01). In Group sAAR, there was a mean .3-mm increase of the ONSD, whereas in Group iAAR, a mean .2-mm decrease could be detected. Both groups roughly reached baseline values by the end of their inpatient stay. ONSD changes seem to be a reliable marker to estimate spinal perfusion. Since OS provides a suitable bedside tool for rapid reevaluation, it may guide physicians in the identification and treatment of patients at high risk for spinal cord ischemia.

Organ protection during aortic cross-clamping.

Open surgical repair of an aortic aneurysm requires aortic cross-clamping, resulting in temporary ischemia of all organs and tissues supplied by the aorta distal to the clamp. Major complications of open aneurysm repair due to aortic cross-clamping include renal ischemia-reperfusion injury and postoperative colonic ischemia in case of supra- and infrarenal aortic aneurysm repair. Ischemia-reperfusion injury results in excessive production of reactive oxygen species and in oxidative stress, which can lead to multiple organ failure. Several perioperative protective strategies have been suggested to preserve renal function during aortic cross-clamping, such as pharmacotherapy and therapeutic hypothermia of the kidneys. In this chapter, we will briefly discuss the pathophysiology of ischemia-reperfusion injury and the preventative measures that can be taken to avoid abdominal organ injury. Finally, techniques to minimize the risk of complications during and after open aneurysm repair will be presented.

Elective Endovascular Aortic Aneurysm Repair Continues to Cost More than Open Abdominal Aortic Aneurysm Repair

Endovascular aortic aneurysm repair (EVAR) is now established as first-line treatment for infrarenal aortic aneurysms in the United States. Recent data from randomized trials suggest that elective EVAR is cost-effective compared with open abdominal aortic aneurysm repair (oAAA). Cost analysis for urgent aneurysm repair has not been reported. We evaluated the cost of elective and urgent EVAR and compared it with oAAA at a tertiary academic medical center. All infrarenal AAA repairs performed from 2004 to 2010 were retrospectively reviewed (n=172). Clinical characteristics of patients receiving EVAR and oAAA repair were compared. Direct costs, payments, and direct cost margin for the index inpatient episode were obtained from the hospital for all patients. Subsequent financial information including clinical, radiologic, and procedural cost was also available for 52 patients who had received all follow-up care in our institution for at least 1 year (EVAR 34, oAAA 18). Overall, elective EVAR patients were older, but oAAA patients had more comorbidities, with significantly more patients having dyspnea at rest and being totally dependent for activities of daily living. EVAR patients had significantly shorter lengths of stay, regardless of urgency and urgent AAA repair occurred more often by oAAA than EVAR (P<0.001; χ2). For elective patients, EVAR costs were 34.21% greater than for oAAA. There was a trend toward lower costs with EVAR versus oAAA in patients treated urgently by a ratio of 1.28:1. The hospital experienced a negative cost margin more often after elective EVAR versus oAAA. Negative cost margins were less frequent following urgent repair but still occurred twice as often in EVAR versus oAAA patients. Cost margins remained negative in all EVAR patients for at least 1 year and only 18% converted to a positive cost margin at a mean of 31months. At a tertiary academic institution, costs for elective EVAR are significantly higher than oAAA. EVAR may be relatively more cost-effective in urgent situations. Negative cost margins were more common in EVAR patients and 1-year follow-up with imaging in the same institution did not result in a positive margin.

Bifurcated-Bifurcated Aneurysm Repair: A Novel Technique to Repair Infrarenal Aortic Aneurysms in the Setting of Iliac Aneurysms

Bifurcated-Bifurcated Aneurysm Repair: A Novel Technique to Repair Infrarenal Aortic Aneurysms in the Setting of Iliac Aneurysms

Acute kidney injury after open and endovascular elective repair for infrarenal abdominal aortic aneurysms

The aim of this study was to evaluate the incidence of acute kidney injury (AKI) after open and endovascular abdominal aortic aneurysm repair according to the Aneurysm Renal Injury Score classification. We retrospectively evaluated 431 patients undergoing elective open aortic repair (OAR; n= 285) or endovascular repair (n= 146) for infrarenal aortic aneurysm. All data regarding preoperative and postoperative serum creatinine concentrations and postoperative outcomes were assessed. Univariate and multivariate logistic regression models investigated the association between AKI and different risk factors and complications. The incidence of AKI was significantly higher after OAR (26.3% vs 5.5%; P< .001). A significant share of patients who experienced AKI were restored to preoperative renal function at discharge (62.5% vs 77.5% in the endovascular and OAR groups, respectively; P= .37). Preoperative serum creatinine concentration was significantly higher in those patients who further developed AKI (1.25 vs 1.04mg/dL; P< .001). At the multivariate analysis, AKI was significantly associated with current smoking (odds ratio [OR], 2.05; 95% confidence interval [CI], 1.19-3.52; P= .01), hypertension (OR, 2.46; 95% CI, 1.21-4.3; P=.01), chronic renal disease (OR, 2.53; 95% CI, 1.42-4.53; P< .001), OAR (OR, 7.3; 95% CI, 3.25-16.42; P< .001), and arrhythmias (OR, 3.16; 95% CI, 1.09-9.13; P= .03). AKI stage did not affect postoperative outcomes, except for a longer hospital stay in patients in stage 2 and stage 3 compared with stage1. AKI is a common but often reversible complication, especially after OAR. There is an urgent need of a common classification for AKI after aortic surgery. New diagnostic markers for AKI should be evaluated in large-scale studies to assess their reliability.

Resultados tras el cambio de estrategia en el sellado distal de endoprótesis aórticas infrarrenales

IntroductionAfter assessing the results our own studies regarding the outcomes of patients in relation to distal sealing strategy, we modified our previous sealing approach of abdominal aortic endografts. For this study, distal sealing on common iliac artery (CI) is proposed when its diameter was less than 16mm, and in external iliac artery (EI) for diameters greater than 16mm. The aim of this study is to assess the effects of the modification of fixation criteria during follow-up. Patients and methodsPatients consecutively treated for infrarenal aortic aneurysms by elective endovascular repair during the period between January 2008 and December 2012 were included.Average iliac growth, type I distal endoleak (Ib), limb thrombosis, re-interventions due to iliac related complications were assessed, as well as overall mortality and aneurysm related mortality.Patients with less than 12 months follow-up were excluded, although they were included in the analysis to assess mortality. ResultsA total of 81 patients accounting for 126 iliacs were included. Distal fixation was carried out at CI in 86 and EI in 40 cases, respectively. Mean follow-up was 30.6±14 months. Average CI growth rate was –0.17±3mm (+1mm when fixation was performed in CI and -2.6mm when for fixation in EI; P=.0001); and -0.10±1.4mm for EI (–0.3mm when fixation was performed in CI and +0.4mm for fixation in EI; P=.01). No type 1b endoleaks or aneurysm ruptures were detected during follow-up. Total iliac re-intervention rate was 3.2% (4 cases, 1.1% in CI vs 7.5% in EI; P=.09). Limb thrombosis rate was higher in patients with sealing in EI (10% Vs 0%; P=.009), as well as the incidence of buttock claudication (37.5% vs. 4.6%; P=.0001). Perioperative mortality rate was 2.5%. Overall and aneurysm-related mortality at 3 years was 19.5% and 2.5% respectively (re-interventions did not have any influence on mortality rates). ConclusionsThe observed results support the strategy modification in distal sealing zone, eliminating the risk of Ib endoleaks and aneurysm rupture in our experience. However, distal sealing in EI was associated with a higher incidence of limb thrombosis (Without any increase in aneurysm-related mortality), and buttock claudication.

The effect of anatomical factors on mortality rates after endovascular aneurysm repair.

SummaryObjectiveThe objective of this study was to investigate the effect of anatomical characteristics on mortality rates after endovascular aneurysm repair (EVAR).MethodsWe investigated 56 EVAR procedures for infrarenal aortic aneurysms performed between January 2010 and December 2013, and the data were supplemented with a prospective review. The patients were divided into two groups according to the diameter of the aneurysm. Group I (n = 30): patients with aneurysm diameters less than 6 cm, group II (n = 26): patients with aneurysm diameters larger than 6 cm. The pre-operative anatomical data of the aneurysms were noted and the groups were compared with regard to postoperative results.ResultsThere were no correlations between diameter of aneurysm (p > 0.05), aneurysm neck angle (p > 0.05) and mortality rate. The long-term mortality rate was found to be high in patients in whom an endoleak occurred.ConclusionWe found that aneurysm diameter did not have an effect on postoperative mortality rates. An increased EuroSCORE value and the development of endoleaks had an effect on long-term mortality rates.

Inflammation, Endoleaks, and Aortic Remodeling--The Chicken or the Egg.

Shalaby and colleagues1have taken a fresh look at inflammationandaortic aneurysmsbyexamining thecontinued remodeling of the residual aneurysmal sac after endovascular repair of infrarenal aortic aneurysms (endovascular aneurysm repair [EVAR]). Two long-term pitfalls for EVAR areendoleaksandcontinuedexpansionof the residual sac.The rate of type II endoleaks may be as low as 15%2 or as high as 27%.3Type II endoleaksusually involve continued flowwithin the aneurysm sac. Approximately 60% resolve within 6 months, but persistence of a type II endoleak after the first 6 months is associatedwith higher rates (55%) of aneurysm sac enlargement.2 The search for risk factors for type II endoleaks and sac expansion have primarily focused on anatomical factors (after all, it is a plumbingproblem): thenumber of patent lumbars, the sizeof the inferiormesenteric artery, theburden of laminated thrombus in the aneurysm, or the technical complexities of the endovascular procedure. Inflammation in the arterialwall has long been suspected as a causative factor for thedevelopment and expansionof an infrarenal aortic aneurysm, which is the most common type of sporadic, nonsyndromic aneurysm. An abundance of inflammatory cells can be found in the aneurysm wall, as well as increases in proteolytic activity and matrix protein degradation.4 This article1 suggests that increased systemic inflammationmay play a role in the failure of sac shrinkage and the development of endoleaks. In a retrospective group of 79 patients undergoingEVAR, 65%had some type of inflammatory condition (eg, allergic rhinitis, osteoarthritis, gout, or rheumatoid arthritis). The “inflammatory” group showed comparable long-termsurvival, experiencedmorepostoperativecomplications (no surprise), and had a significantly higher rate of type II endoleaks, as well as less sac shrinkage in the longterm. Their observations support the intuitive idea that excessive systemic inflammation leads to a failure of aorticwall fibrosis and contraction, resulting in retarded sac shrinkage. Why should this cause more endoleaks, primarily an anatomic problem? Instead of the conventional wisdom that endoleaks cause a failure of sac shrinkage, perhaps the reverse is true: does failure of sac shrinkage foster endoleaks? Themain caveat to their conclusions is that their classification of systemic inflammatory diseasewas based on a diagnosis proffered by others and lacked independent confirmation or, even better, some objective measurements of inflammation.Without confirmatorydata, itwouldbehard to understandhowallergic rhinitisandrheumatoidarthritismight confer a similar derangement of the systemic inflammatory state. This points to a key therapeutic question: what aspect(s) of systemic inflammationmightbeassociatedwith failure of aortic remodeling and which pathways are involved? Some directions for further study may be found in disorders in transforminggrowth factor–βsignalingandtheSMADgenes, bothofwhich share clinical associationswith aneurysmal diseases and osteoarthritis.4,5

Radiation Exposure in Endovascular Infra-Renal Aortic Aneurysm Repair and Factors that Influence It.

ObjectiveThe endovascular repair of aortic abdominal aneurysms exposes the patients and surgical team to ionizing radiation with risk of direct tissue damage and induction of gene mutation. This study aims to describe our standard of radiation exposure in endovascular aortic aneurysm repair and the factors that influence it.MethodsRetrospective analysis of a prospective database of patients with abdominal infra-renal aortic aneurysms submitted to endovascular repair. This study evaluated the radiation doses (dose area product (DAP)), fluoroscopy durations and their relationships to the patients, aneurysms, and stent-graft characteristics.ResultsThis study included 127 patients with a mean age of 73 years. The mean DAP was 4.8 mGy.m2, and the fluoroscopy time was 21.8 minutes. Aortic bilateral iliac aneurysms, higher body mass index, aneurysms with diameters larger than 60 mm, necks with diameters larger than 28 mm, common iliac arteries with diameters larger than 20 mm, and neck angulations superior to 50 degrees were associated with an increased radiation dose. The number of anatomic risk factors present was associated with increased radiation exposure and fluoroscopy time, regardless of the anatomical risk factors.ConclusionThe radiation exposure during endovascular aortic aneurysm repair is significant (mean DAP 4.8 mGy.m2) with potential hazards to the surgical team and the patients. The anatomical characteristics of the aneurysm, patient characteristics, and the procedure's technical difficulty were all related to increased radiation exposure during endovascular aortic aneurysm repair procedures. Approximately 40% of radiation exposure can be explained by body mass index, neck angulation, aneurysm diameter, neck diameter, and aneurysm type.

Endovascular Treatment of Infrarenal Aortic Aneurism with Ovation Abdominal Stent Graft System

Purpose: This case reports and describes an endovascular aneurysm repair treated with Ovation® abdominal stent graft system (Tri Vascular Inc, Santa Rosa, Calif). A seventy-four-year-old male checked in at our hospital complaining of severe abdominal pain. On his physical exam and initial image study no gastro-intestinal anomalies were found that justified the complaint. The patient was then submitted to an abdominal-pelvic computed tomography angiography where was confirmed our previous conjecture of an infrarenal aortic aneurysm. The patient was forwarded for endovascular treatment using endoprosthesis (current generation stent grafts) with an ultra-low-profile delivery system, with excellent conformability, and kink resistant iliac limbs. The patient’s development following treatment was beyond expectations with radical clinical improvement and complete relief of symptoms. The results acquired in this case supports the viability an efficiency of abdominal aortic aneurysm endovascular treatment with the ovation stent graft system to treat a wide range of anatomies, especially in difficult anatomies, such as it is in this particular case.

Re-Rupture of Abdominal Aortic Aneurysm after Endovascular Repair from Infected Endograft

Introduction: Successful endovascular aortic aneurysm repair (EVAR) aims to prevent catastrophic rupture, however despite technical excellence at index operation, long term follow up remainsm and atory. This is due to the fact that delayed aortic rupture may occur in certain patients after EVAR. We present a technically challenging case which illustrates this concern. Case report: An 82 year old man underwent successful EVAR using a redesigned, clinical trial graft (Medtronic, Minneapolis, MN), five years prior to presentation. He was lost to follow after the initial procedure. At presentation to us, he demonstrated a 13.5cm, ruptured infrarenal aortic aneurysm due to proximal aortic neck enlargement and endograft slippage. Emergency repair included a proximal supra-renal endograft extension (Endologix, Irvine, CA), femoralfemoral bypass (PTFE), and open abdomen with negative-pressure therapy (Abthera, KCI, San Antonio, TX) He survived and was discharged with close follow-up. He re-presented six months later with flank pain and a WBC 22,000. A CT Scan was concerning for a new contained aortic rupture (16cm) and a recurrent proximal endograft slip. High clinical suspicion resulted in a return to operating room for axillary to femoralfemoral artery bypass (PTFE), followed by explantation of the endograft system, aortic sac resection, and omental flap coverage. Operative cultures yielded Staphylococcus epidermis. He survived again and was discharged on a plan for long term antibiotics on postoperative day 10. Conclusion: Long term follow up after EVAR may help to identify patients at high risk for endo-graft failures. Aortic neck enlargement leading to rupture may result from primary aneurysm growth, however infection can be an important cause. Time honored open aortic surgical techniques remain an important tool for every vascular surgeon.

The Need for Universal Access to More Flexible Endovascular Stent Graft Constructs

Abdominal aortic aneurysm (AAA) is the 13th leading cause of death in the United States, responsible for over 15,000 deaths annually. With improved screening methods and the advent of endovascular surgery, mortality from AAA has significantly decreased over the past twenty years [1]. Today it is estimated that >70% of aneurysms are amenable to endovascular repair [2]. While endovascular aortic aneurysm repair (EVAR) is confined to the treatment of infra-renal AAA with a ≥10 mm neck, complex endovascular stent grafts have been developed to treat AAA with <4 mm infra-renal neck (juxta-renal), involving the renal or visceral vessel orifices (para-renal or para-visceral), or extending to the diaphragm (Type IV thoraco-abdominal aneurysm) or thoracic aorta. It is estimated that 16% of infrarenal aortic aneurysms are juxta-renal, and a smaller percentage involve the more proximal abdominal aorta [3]. Fenestrated and branched endografts have been developed to treat proximal AAAs not amenable to standard EVAR. However, the extent of what can be treated is limited in the United States by the specific instructions for use (IFU) of each device and what has gone through the rigorous process of FDA approval. Instructions for use outline the recommended anatomic constraints for each device to maximize positive outcomes by guiding patient and device selection. Physicians can treat outside of the IFU but bear significant liability. While certain centers in the US conducting investigational research have access to order endografts outside of their IFU, practitioners in other countries are able to customize devices without these constraints. Patients who could otherwise undergo endovascular repair may be subject to high-risk open surgery, off-label use of devices to perform chimney/snorkel procedures, off-label use of existing FDA approved fenestrated devices, or medical management (at increased risk for aneurysm related death) due to these current restrictions.

Magyarországon végzett infrarenalis aortaaneurysma-műtétek eredményei az Érsebészeti Regiszter adatai alapján (2010–2014)

The Hungarian Society for Vascular Surgery decided to analyse and publish regularly the data of the Hungarian Vascular Registry. The aim of the authors was to present the outcome of infrarenal aortic aneurysm surgeries performed during the past five years. Prospectively collected multicentric data obtained from the Hungarian Vascular Registry between January 1, 2010 and December 31, 2014 were analysed retrospectively. Statistical analysis was performed using Fisher's exact test and odds ratio calculation. It was found that 16.72% of the 1435 operations were performed for ruptured aneurysms. Five institutes having the highest capacity performed 78.4% of the operations. In the ruptured aortic aneurysm group the age of patients was 71.77±9.82 years (mean±SD), and perioperative mortality was 33.75%. In the intact aortic aneurysm group the age of patients was 69.50±8.46 years and the perioperative mortality was 3.51%. In both groups perioperative mortality (ruptured: p<0,05, OR = 0.11; intact: p<0.05, OR = 0.26) and the length of hospital stay (ruptured: p<0.05, OR = 4.55; intact: p<0.001, OR = 4.27) were significantly lower in patients who had endovascular repair compared to those with open repair. In both groups perioperative mortality (ruptured: p<0.0001, OR = 0.32; intact: p<0.0001, OR = 0.23) and length of hospital stay (ruptured: p<0.05, OR = 3.16; intact: p<0.001, OR = 3.84) were significantly lower in the five institutes having the highest capacity than in the remaining institutes. In patients having endovascular repair and in institutes with high capacity the perioperative mortality and length of hospital stay were significantly lower.

Predictors and outcomes of endoleaks in the Veterans Affairs Open Versus Endovascular Repair (OVER) Trial of Abdominal Aortic Aneurysms

The Veterans Affairs Open Versus Endovascular Repair (OVER) Trial of Abdominal Aortic Aneurysms study was a randomized controlled trial comparing open vs endovascular repair (EVAR) in standard-risk patients with infrarenal aortic aneurysms. The analysis reported here identifies characteristics, risk factors, and long-term outcome of endoleaks in patients treated with EVAR in the OVER cohort. The OVER trial enrolled 881 patients, of whom 439 received successful EVAR. Logistic regression analysis was used to identify predictors for endoleaks and secondary interventions. Kaplan-Meier survival analysis, longitudinal plots, and generalized linear mixed models methods were used to describe time to endoleak detection, resolution, or death. During a mean follow-up of 6.2 ± 2.4 years, 135 patients (30.5%) developed 187 endoleaks. Four patients with EVAR went on to rupture; these four patients did not all have an endoleak. Mortality between patients who did and did not develop endoleaks was not significantly different. The 187 endoleaks included 12% type I, 76% type II, 3% type III, 3% type IV, and 6% indeterminate. Patient demographics and vascular risk factors were not associated with endoleak development. The presence of endoleaks resulted in an increase in aneurysm diameter over time (P < .0001). Fifty-three percent of endoleaks resolved spontaneously, and 31.9% received secondary interventions. The initial aneurysm size independently predicted a need for secondary interventions (P < .0003). Delayed type II endoleaks (detected >1 year after EVAR) were associated with aneurysm enlargement compared with the early counterpart. There was no difference in aneurysm size or length of survival between type II and other types of endoleak. We present one of the most comprehensive and longest follow-up analyses of patients treated with aortic endografts. Endoleaks were common and negatively affected aneurysm diameter reduction. Delayed type II endoleaks were associated with late aneurysm diameter enlargement. Endoleaks and aneurysm diameter enlargement were not associated with excess mortality compared with those without these features.

An Experimental Set-Up for Navigated-Contrast-Agent and Radiation Sparing Endovascular Aortic Repair (Nav-CARS EVAR)

Over the last decade endovascular stenting of aortic aneurysm (EVAR) has been developed from single centre experiences to a standard procedure. With increasing clinical expertise and medical technology advances treatment of even complex aneurysms are feasible by endovascular methods. One integral part for the success of this minimally invasive procedure is innovative and improved vascular imaging to generate exact measurements and correct placement of stent prosthesis. One of the greatest difficulty in learning and performing this endovascular therapy is the fact that the three-dimensional vascular tree has to be overlaid with the two-dimensional angiographic scene by the vascular surgeon. We report the development of real-time navigation software, which allows a three-dimensional endoluminal view of the vascular system during an EVAR procedure in patients with infrarenal aortic aneurysm. We used the preoperative planning CT angiography for three-dimensional reconstruction of aortic anatomy by volume-rendered segmentation. At the beginning of the intervention the relevant landmarks are matched in real-time with the two-dimensional angiographic scene. During the intervention the software continously registers the position of the guide-wire or the stent. An additional 3D-screen shows the generated endoluminal view during the whole intervention in real-time. We examined the combination of hardware and software components including complex image registration and fibre optic sensor technology (fibre-bragg navigation) with integration in stent graft introducer sheaths using patient-specific vascular phantoms in an experimental setting. From a technical point of view the feasibility of fibre-Bragg navigation has been proven in our experimental setting with patient-based vascular models. Three-dimensional preoperative planning including registration and simulation of virtual angioscopy in real time are realised. The aim of the Nav-CARS-EVAR concept is reduction of contrast medium and radiation dose by a three-dimensional navigation during the EVAR procedure. To implement fibre-Bragg navigation further experimental studies are necessary to verify accuracy before clinical application.

A Rare Presentation of an Aortoenteric Fistula After Aortic Aneurysm Repair

Aortoenteric fistula is a well described complication of endovascular repair of abdominal aortic aneurysms (AAA). Aortoenteric fistula formation is rare but potentially life-threatening and has been reported in 0.6%-2% of cases. Multiple causes of aortoenteric fistulas have been described including endograft infection, kinking of endograft within the aorta, or simple erosion of the foreign material. Although acute gastrointestinal bleeding is the most common presentation, chronic gastrointestinal bleeding and asymptomatic presentation have been described. Given its close proximity to the descending aorta, the third portion of the duodenum is the most common location for aortoenteric fistulas. We report an unusual case of an asymptomatic aortoenteric fistula to the duodenal bulb. An 80 year old female with history of chronic obstructive pulmonary disease, hypertension and peripheral vascular disease initially presented with intermittent abdominal pain and hematemesis. CT scan showed an infrarenal 6.5 cm AAA compressing the adjacent duodenum with evidence of air within the thrombus suggesting presence of an aortoenteric fistula to third portion of the duodenum. Patient underwent emergent placement of aortouniiliac endograft stent for repair of AAA by interventional radiology. She was maintained on total parenteral nutrition post procedure. Two months after AAA repair, an upper endoscopy was performed prior to the initiation of oral feeding and showed a 3 cm ulcer with graft material in the duodenal bulb. Patient was asymptomatic at this time with no evidence of gastrointestinal bleeding. There was no evidence of graft infection or migration. Although an unusual location, we believe the patient had developed a second aortoenteric fistula to the duodenal bulb. In recent years, endovascular aneurysm repair is the procedure of choice for repair of infrarenal aortic aneurysms. There have been multiple rare complications associated with this procedure, aortoenteric fistulas being one of the most described. Most patients present with acute gastrointestinal bleeding with fistulas affecting the third portion of the duodenum necessitating endovascular or surgical repair. There are no reported cases of asymptomatic fistulization to the duodenal bulb. Gastroenterologists should be aware of this unusual presentation.Figure 1

High Resolution Strain Analysis Comparing Aorta and Abdominal Aortic Aneurysm with Real Time Three Dimensional Speckle Tracking Ultrasound

Ultrasound measurement of aortic diameter for aneurysm screening allows supervision of aneurysm growth. Additional biomechanical analysis of wall motion and aneurysm deformation can supply information about individual elastic properties and the pathological state of the aortic wall. Local aortic wall motion was analyzed through imaged aortic segments according to age and pathology. Sixty-five patients were examined with a commercial four dimensional ultrasound system (4D-US). Three groups were defined: patients with normal aortic diameter and younger than 60 years of age (n = 21); those with normal aortic diameter and older than 60 years of age (n = 25); and those with infrarenal aortic aneurysm (n = 19). A diastolic reference shape of aortic wall segments was obtained and local and temporally resolved wall strain was determined. Indices characterizing the resulting wall strain distribution were determined. The analysis of biomechanical properties displayed increasing heterogeneous and dyssynchronous circumferential strain with increasing patient age. Young patients exhibited higher mean strain amplitude. The distribution of the spatial heterogeneity index and local strain ratio was inversely proportional to age. The maximum local strain amplitude was significantly higher in the young (0.26 ± 0.17) compared with the old (0.16 ± 0.07) or aneurysmal aorta (0.16 ± 0.10). Temporal dyssynchrony significantly differed between young (0.13 ± 0.10) and old (aneurysmal 0.31 ± 0.04, non-aneurysmal 0.29 ± 0.05), regardless of aortic diameter. The spatial heterogeneity index and local strain ratio differentiate non-aneurysmal and aneurysmal aorta, regardless of age. 4D-US strain imaging enables description of individual wall motion (kinematics) of the infrarenal aorta with high spatial and temporal resolution. Functional differences between young, old, and aneurysmal aorta can be described by mean (circumferential) strain amplitude, the spatial heterogeneity index, and the local strain ratio. Further investigation is required to refine this new perspective of patient individualized characterization of the pathological AAA wall and eventually to rupture risk stratification.

Evolution of the Diameter of Infrarenal Aortic Aneurysms Treated by EVAR and Study of the Predictive Factors of Anatomical Failure

To determine if the evolution of the diameter of an AAA one year after EVAR predicts the long-term evolution.

New Applications and Indications for Contrast-Enhanced Sonography in Endovascular Aortic Repair

After edovascular repair of infrarenal aortic aneurysms (EVAR) endoleaks may occur necessitating further therapy. Therefore a reliable method for follow-up imaging after EVAR for detection and control of endoleaks is of high importance. Contrast-enhanced sonography (CEUS) does not require the application of nephrotoxid contrast media and does not stress the patient. CEUS is increasingly used and enables a quick, non-invasive follow-up examination for patient after EVAR. In addition, interventions as therapy for endoleaks may be executed using ultrasound. Initial experience with CEUS-guided aortic stenting shows that the amount of contrast media as well as X-ray time may be reduced.