Diagnosis and treatment of inferior mesenteric arterial endoleaks after endovascular repair of abdominal aortic aneurysms

Applying patient characteristics, stent-graft selection, and pre-operative computed tomographic angiography data to a machine learning algorithm: Is endoleak prediction possible?

INTRODUCTION

This study aims to predict endoleak after endovascular aneurysm repair (EVAR) using machine learning (ML) integration of patient characteristics, stent-graft configuration, and a selection of vessel lengths, diameters and angles measured using pre-operative computed tomography angiography (CTA).

METHODS

We evaluated 1-year follow-up CT scans (arterial and delayed phases) in patients who underwent EVAR for the presence or absence of an endoleak. We also obtained data on the patient characteristics, stent-graft selection, and preoperative CT vessel morphology (diameter, length, and angle). The extreme gradient boosting (XGBoost) for the ML system was trained on 30 patients with endoleaks and 81 patients without. We evaluated 5217 items in 111 patients with abdominal aortic aneurysms, including the patient characteristics, stent-graft configuration and vascular morphology acquired using pre-EVAR abdominal CTA. We calculated the area under the curve (AUC) of our receiver operating characteristic analysis using the ML method.

RESULTS

The AUC, accuracy, 95% confidence interval (CI), sensitivity, and specificity were 0.88, 0.88, 0.79-0.97, 0.85, and 0.91 for ML applying XGBoost, respectively.

CONCLUSIONS

The diagnostic performance of the ML method was useful when factors such as the patient characteristics, stent-graft configuration and vessel length, diameter and angle of the vessels were considered from pre-EVAR CTA.

IMPLICATIONS FOR PRACTICE

Based on our findings, we suggest that this is a potential application of ML for the interpretation of abdominal CTA scans in patients with abdominal aortic aneurysms scheduled for EVAR.

A systematic review of the current status of interventions for type II endoleak after EVAR for abdominal aortic aneurysms

OBJECTIVE

To study the mid- and long-term outcomes of type II endoleak treatment after EVAR and the technical aspects of different techniques to exclude endoleaks which different embolic agents.

METHODS

A systematic review was performed using the approach recommended by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for meta-analyses of interventional studies. The comprehensive search was conducted using the following database: MEDLINE, EMBASE, and the Cochrane Library. Patient characteristic, intervention approaches, embolic agents, and results at mid and long term follow up were studied.

RESULTS

A total of 6 studies corresponding to a total of 141 patients fulfilled the inclusion criteria with a mean age of 73-78.6 years and a mean duration of follow up varying from 25 to 42 months. There were different techniques for embolization used (translumbar, transarterial, and transcaval approach) with various types of embolic agents. In all studies, the indication for embolization of the type II endoleaks was sac enlargement of more than 5 mm. A wide range of technical success rate was reported regardless of the intervention strategy being used (17,6%-100%). The overall technical success rate of all studies was 62%.

CONCLUSION

This systematic review shows that there is a wide variety of techniques to exclude a persistent type II endoleak. Different kinds of embolic agents have be used. Due to a lack of peer reviewed data on longterm follow-up, it was not possible to come to recommendations what treatment would be the best for a durable exclusion of a persistent type II endoleak after an initially successful EVAR. There remains an urgent need for proper executed studies, either randomized or with close observation in relation to longer follow-up.

A novel approach for treating type II endoleaks utilizing contrast-enhanced ultrasound

Endoleaks are a frequent and well-known complication after endovascular repair of aortic aneurysms. An endoleak can lead to increased intrasac pressure, sac enlargement, and potential aneurysm rupture. Type II endoleaks result from retrograde filling of aortic branch vessels and can be treated with surgical, endovascular, or direct percutaneous approaches. Direct percutaneous treatment typically involves embolization of the perfused endoleak cavity typically using a translumbar approach with fluoroscopic guidance. We illustrate a novel image-guided approach for percutaneous transabdominal endoleak treatment using contrast-enhanced ultrasound in combination with fluoroscopy.

Comparison of Cost and Efficacy of Trufill® vs Histoacryl® n-Butyl Cyanoacrylate for Translumbar Type 2 Endoleak Embolization

PURPOSE

The study aimed to compare the cost and efficacy of translumbar approach type 2 endoleak repairs using either Trufill® or Histoacryl® n-BCA liquid embolic.

METHOD AND MATERIALS

This was a retrospective review of patients who had translumbar approach type 2 endoleak repairs using either Trufill® or Histoacryl®. Patients were included if they underwent a technically successful type 2 endoleak repair via a translumbar approach with Trufill® or Histoacryl® n-BCA. A multivariable analysis was performed with the primary clinical outcome of percent change in aneurysm diameter per month compared. Procedure cost was calculated based on typical materials used.

RESULTS

20 Trufill® and 14 Histoacryl® patients were included. The mean procedure cost was higher for Trufill® ($5,757.30 vs. $1,586.09, p ≤ 0.001). There was no significant difference between Trufill® or Histoacryl® patients for age at first embolization, gender, total number of embolizations, number of feeding branches, aneurysm sac size prior to embolization, or residual endoleak at first follow-up. Trufill® patients had more coils used (12.0 vs. 4.3, p = 0.0007), less glue used (0.9 vs. 2.1 mL, p < 0.001), longer follow-up duration (33.5 vs. 13.2 months, p = 0.002), more follow-up CT angiograms (CTA) (3.7 vs. 1.9, p = 0.01), and larger excluded aneurysm sac size at most recent CTA (7.1 cm vs. 5.9 cm, p = 0.04). Percent change in sac diameter per month was not significantly different between Trufill® and Histoacryl® (0.21% vs. -0.25%/month, p = 0.06, respectively). There were no complications.

CONCLUSION

Use of Histoacryl® over Trufill® n-BCA resulted in significantly less procedural cost while maintaining safety and efficacy.

Review of Type III Endoleaks

Endoleak remains a significant challenge to endovascular aneurysm repair, particularly as evolving techniques and devices have allowed treatment of increasingly complex aneurysm anatomy with increasing number of device components. Intervention is recommended for both type I and III endoleaks due to their risk of rupture, and endovascular techniques are the favored modality with placement of a bridging endograft over the endoleak defect. Conversion to open surgical repair remains the definitive option in cases where less invasive methods have failed or are precluded. In this article, the authors review evidence on the etiology, incidence, diagnosis, and current techniques for type III endoleak management.

Preoperative Inferior Mesenteric Artery Embolization is a Cost-effective Technique that May Reduce the Rate of Aneurysm Sac Diameter Enlargement and Reintervention After EVAR

BACKGROUND

Type II endoleaks are the most common complications after endovascular repair of abdominal aortic aneurysms (EVARs). Some studies have shown the benefit of preventive inferior mesenteric artery (IMA) embolization, but its efficacy and cost-effectiveness continue to be controversial. The aim of this study was to evaluate the efficacy of this procedure on the increase in aneurysmal sac diameter during follow-up.

MATERIALS AND METHODS

All consecutive patients who underwent the embolization of the IMA before EVAR in our center, between January 2014 and July 2016, were included. We retrospectively compared the diameter of the aortic aneurysm sac, the rate of endoleak and reinterventions, and the theoretical cost of management between these patients (group 2) and a historical cohort of patients treated for EVAR before January 2014 who did not undergo prior IMA embolization (group 1).

RESULTS

Two hundred twenty-four patients were retrospectively analyzed. After exclusion, we compared a group of 37 embolized patients with a control group of 46 patients. The rate of enlargement in the aneurysmal sac diameter was significantly higher in the control group at 2 years (27.9% vs. 4.3%, P = 0.025). The type II endoleak rate at 2 years was significantly higher in the control group (53.1% vs. 18.2%, P = 0.012), as was the aneurysm-related reintervention rate (31.1% vs. 8.1%, P = 0.013). Multivariate analysis confirmed these results. At 2 years of follow-up, there was no difference in the overall cost of patient management between the 2 groups.

CONCLUSIONS

Preventive IMA embolization is an effective, reliable, and cost-effective technique that seems to reduce the rate of the aneurysmal sac diameter enlargement, type II endoleak, and reinterventions after EVAR.

Medium-term outcomes of fenestrated endovascular repair of juxtarenal abdominal aortic aneurysms

BACKGROUND

Abdominal aortic aneurysms pose a substantial clinical burden, and a significant proportion are not anatomically suitable for open repair or standard endovascular aneurysm repair (EVAR), instead requiring fenestrated EVAR (fEVAR). We sought to compare clinical outcomes and trends over time in patients undergoing fEVAR in Australia.

METHODS

We conducted a retrospective analysis of all patients undergoing fEVAR at a tertiary referral centre between 2010 and 2015, including outcomes and complications, both as inpatients and after discharge.

RESULTS

Thirty-nine patients underwent fEVAR during the study period, with mean age of 75 years and mean aneurysm size of 61 mm. One hundred and thirty-four target vessels were treated and inhospital mortality was 5% (two patients). There were nine inhospital, eight Type II and one Type III endoleaks. Ten patients suffered acute kidney injury, one of whom required dialysis. Mean follow-up was 14.5 months (range: 0-46.7). Target vessel patency was 99.2% at follow-up. There were six Type II endoleaks at follow-up, and two patients died during the follow-up period (of non-aneurysm-related causes).

CONCLUSION

fEVAR is an effective treatment with low morbidity and mortality, and we have demonstrated excellent survival and target vessel patency at a mean follow-up of 14 months. Endoleak rates were low, despite the high complexity of the aneurysms treated.

Direct sac puncture versus transarterial embolization of type II endoleaks: An evaluation and comparison of outcomes

Purpose To determine the outcomes of type II endoleak embolization with aneurysm sac obliteration and whether the approach - direct sac puncture or transarterial - affects outcome. Methods A retrospective review of patients who underwent endovascular aneurysm repairs and subsequent type II endoleak embolization over 10 years was performed. Twenty-three patients (median age: 73 years, range: 40-88 years) underwent 35 embolizations. Embolization was performed with the goal of obliterating both the endoleak sac and feeding vessels. Embolization agents used include cyanoacrylate glue only (48%), glue and coils (36%), coils only (13%), and other (3%). Results Mean follow-up was 21.8 months. Patients underwent an average of 1.5 embolizations, with 35% requiring more than one. Technical success rate was 89%. Freedom from aneurysm sac expansion was achieved in 91%. Freedom from type II endoleak was accomplished in 70%. There were no ruptured aneurysms during the follow-up period. Direct sac puncture and transarterial approaches had similar incidences of aneurysm sac growth ( p = 0.74), persistent type II endoleak ( p = 0.32), and complications ( p = 0.64). However, direct sac puncture had significantly shorter fluoroscopy ( p < 0.001) and total procedure times ( p < 0.001) than transarterial embolizations. Conclusion Direct sac puncture and transarterial embolization of type II endoleak with aneurysm sac obliteration are similarly effective for the prevention of aneurysm sac growth. However, direct sac puncture is our preferred approach given its significantly shorter fluoroscopic and procedural times.

Predictive Factors for the Development of Type 2 Endoleak Following Endovascular Aneurysm Repair

Type 2 endoleak (T2EL) is the most common complication following endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms. The management of T2ELs is controversial due to the relatively low incidence of negative outcomes when secondary intervention is avoided. Some studies challenge this practice as demonstrated by adverse events following conservative treatment of T2ELs. Evidence has shown that the preoperative computed tomographic angiogram can predict the development of T2EL based on a patient's arterial anatomy, specifically vessels associated with increased rates of post-EVAR endoleak development. Preoperative embolization of those aortic branch vessels associated with T2ELs has shown decreased rates of postoperative complications and may result in a decreased need for surveillance and reintervention.

Detecting Aortic Graft Complications: A Spectrum of Computed Tomography Findings

Endovascular aneurysm repair (EVAR) is a successful technique as well as an excellent alternative to the surgical management of abdominal aortic aneurysms. EVAR has improved the mortality and morbidity of many patients who would have otherwise suffered greatly from the consequences of abdominal aortic aneurysms. However, EVAR is not without complications. Some complications require lifelong surveillance, whereas others may necessitate immediate surgical intervention. We discuss the various modalities available for the surveillance as well as the common complications that can be seen on computed tomography.

Predictive Factors for Type II Endoleaks after Treatment of Abdominal Aortic Aneurysm by Conventional Endovascular Aneurysm Repair

BACKGROUND

The aim of this study was to identify the predictive factors for the development of type II endoleaks (EL-II) after endovascular aneurysm repair (EVAR).

METHODS

We assessed the preoperative and postoperative computed tomography data of 308 patients who underwent EVAR between 2000 and 2012 and in 84 of whom primary or secondary EL-II occurred. The data analyzed were: demographics, number and diameter of lumbar arteries (LAs), inferior mesenteric artery (IMA), median sacral artery (MSA), accessory renal arteries (ARas), maximum diameter of infrarenal abdominal aortic aneurysm, diameter and length of proximal aortic neck. Statistical analysis was performed using Stata software (version 12). Categorical parameters were compared between groups using chi-squared or Fisher's exact tests as appropriate. Continuous variables were analyzed using Student's t-test or Mann-Whitney test as appropriate (normality studied by the Shapiro-Wilk and homoscedasticity verified using the Fisher-Snedecor test).

RESULTS

Of the 308 patients included (mean age, 73.8 ± 8.74 years), 284 (92%) were men, 61 (20%) were smokers, 113 (37%) had chronic obstructive pulmonary disease, 215 (70%) were taking antiplatelet. Respectively, 13, 51, 60, 103, 28, 40, 2, and 7 patients had 1, 2, 3, 4, 5, 6, 7, and 8 patent LAs. Before surgery, 221 IMAs and 136 MSA were patent. The sources of EL-II were: LA (n = 51), IMA (n = 22), MSA (n = 1), IMA and LA (n = 8), IMA and ARa (n = 1), and unknown (n = 1). Logistic regression models adjusting for clinically relevant covariables (age, American Society of Anesthesiologists, smoking status, dyslipidemia, and diuretics) were proposed to study morphologic EL-II predictive factors, first in the entire population, and then in the more specific population for whom IMA was patent. Risk factors of occurrence EL-II were: permeability of the IMA (70 patients [83%] vs. 155 [69%], P = 0.01), IMA diameter (3.49 mm vs. 2.71 mm, P < 0.001), number of LAs patent higher than or equal to 4 (P < 0.001), the mean LA diameter greater than 2.4 mm (P < 0.001), and MSA diameter (2.28 mm vs. 1.94 mm; P < 0.01).

CONCLUSIONS

Our results show the major role of the number and diameter of the patent aortic branches in the development of EL-II. As they can result in complications increasing the morbidity and mortality after EVAR, it is relevant to identify the risk factors of their occurrence.

MDCT of endoleaks following endovascular repair of abdominal aortic aneurysms

Endovascular aneurysm repair has been used to repair abdominal aortic aneurysms but necessitates surveillance to diagnose the delayed possibility of endoleak formation. Multi-detector computer tomography (MDCT) of the abdomen is one imaging technique used to diagnose enlargement of the aneurysm sac that may be indicative of endoleaks. MDCT has a role in identifying the initial endoleak formation and providing signs suggestive of the specific endoleak subtype; thus it is necessary for radiologists to be familiar with the findings of endoleak seen on MDCT. In this pictorial review, we explore the various types of endoleaks and their appearance on MDCT.

The Roadside Technique for Type II Endoleak Embolization 4 Years after Endovascular Aortic Aneurysm Repair

Endoleaks are the most common cause of reintervention after endovascular aortic aneurysm repair (EVAR). Type II endoleaks have been implicated as a risk factor for expansion and rupture. Several techniques have been described to manage type II endoleaks, being transarterial catheterization the most commonly used. In some cases this technique can be difficult or impossible to achieve. We report the use of a technique that offers a direct access to the aneurysm sac and the possibility of catheterization of the involved vessels or the embolization of the communication between them, even 4 years after EVAR.

Embolization by micro navigation for treatment of persistent type 2 Endoleaks after endovascular abdominal aortic aneurysm repair

Background:Endovascular repair has become established as a safe and effective method for treatment of abdominal aortic aneurysms. One major complication of this treatment is leakage, or endoleaks, of which type 2 leaks are the most common.Objective:To conduct a brief review of the literature and evaluate the safety and effectiveness of embolization by micronavigation for treatment of type 2 endoleaks.Method:A review of medical records from patients who underwent endovascular repair of abdominal aortic aneurysms identified 5 patients with persistent type 2 endoleaks. These patients were submitted to embolization by micronavigation.Results:In all cases, angiographic success was achieved and control CT scans showed absence of type 2 leaks and aneurysm sacs that had reduced in size after the procedure.Conclusion:Treatment of type 2 endoleaks using embolization by micronavigation is an effective and safe method and should be considered as a treatment option for this complication after endovascular repair of abdominal aortic aneurysms.

Type 2 Endoleaks Post-EVAR: Current Evidence for Rupture Risk, Intervention and Outcomes of Treatment

Type 2 endoleaks (EL2) are the most commonly encountered endoleaks following EVAR. Despite two decades of experience, there remains considerable variation in the management of EL2 with controversies ranging from if to treat, when to treat and how to treat. Here, we summarise the available evidence, describe the treatment techniques available and offer guidelines for management.

Preoperative inferior mesenteric artery embolization before endovascular aneurysm repair: decreased incidence of type II endoleak and aneurysm sac enlargement with 24-month follow-up

PURPOSE

To review the effect of preoperative embolization of the inferior mesenteric artery (IMA) before endovascular aneurysm repair (EVAR) on subsequent endoleaks and aneurysm growth.

MATERIALS AND METHODS

Between August 2002 and May 2010, 108 patients underwent IMA embolization before EVAR. Coil embolization was performed in all patients in whom the IMA was successfully visualized and accessed during preoperative conventional angiography. In this cohort, the incidences of type II endoleak, aneurysm sac volume enlargement at 24 months, and repeat intervention were compared with a group of 158 consecutive patients with a patent IMA on preoperative computed tomography angiography but not on conventional angiography, who therefore did not undergo preoperative embolization.

RESULTS

The incidence of type II endoleak was significantly higher in patients not treated with embolization (49.4% [78 of 158] vs 34.3% [37 of 108]; P = .015). The incidence of secondary intervention for type II endoleak embolization was also significantly higher in those who did not undergo embolization (7.6% [12 of 158] vs 0.9% [one of 108]; P = .013). At 24 months, an increase in aneurysm sac volume was observed in 47% of patients in the nonembolized cohort (21 of 45), compared with 26% of patients in the embolized cohort (13 of 51; P = .03). No aneurysm ruptures or aneurysm-related deaths were observed in either group. One patient in the embolization group developed mesenteric ischemia and ultimately died.

CONCLUSIONS

Preoperative embolization of the IMA was associated with reduced incidences of type II endoleak, aneurysm sac volume enlargement at 24 months, and secondary intervention.

Quality improvement guidelines for imaging detection and treatment of endoleaks following endovascular aneurysm repair (EVAR)

Major concerns after aortic aneurysm repair are caused by the presence of endoleaks, which are defined as persistent perigraft flow within the aortic aneurysm sac. Diagnosis of endoleaks can be performed with various imaging modalities, and indications for treatment are based on further subclassifications. Early detection and correct classification of endoleaks are crucial for planning patient management. The vast majority of endoleaks can be treated successfully by interventional means. Guidelines for Imaging Detection and Treatment of endoleaks are described in this article.

Transcatheter Transcaval Embolization of a Type II Endoleak After EVAR Using a Transseptal Needle-Sheath System

Purpose. The purpose of this study is to present an alternative technique for management of a type II endoleak associated with aneurysm sac enlargement. Technique. We report the use of a transseptal needle-sheath system for a transcatheter transcaval embolization (TTE) in a 3-staged treatment of a persistent type II endoleak after abdominal EVAR. Inferior vena cava is cannulated through a femoral venous access, and aneurysmal sac access is gained with a puncture through the walls of the 2 vessels at the site where the vein is adjacent to the aneurysm. The whole system (sheath–dilator–needle) is then advanced across the vascular walls into the aortic sac. Thus, embolization with glue is performed. Conclusion. The TTE using a transseptal needle-sheath system demonstrated to be feasible and effective to treat a persistent type II endoleak after failure of 2 attempts of transarterial embolization of the feeding vessels.

Ruptured aortic aneurysm from late type II endoleak treated by transarterial embolization

Endoleak is the most common complication after endovascular aneurysm repair. The most common type of endoleak, a type II endoleak, typically follows a benign course and is only treated when associated with increasing aneurysm size. In this case report, we describe a ruptured abdominal aortic aneurysm due to a late, type II endoleak occurring 10 years after endovascular aneurysm repair that was successfully treated by transarterial embolization.

Treatment of Type II Endoleaks With Ethylene-Vinyl-Alcohol Copolymer (Onyx)

We report our single-center experience in treating 101 type II endoleaks with ethylene-vinyl-alcohol copolymer (EVOH, Onyx). In all, 65 endoleaks were embolized transarterially, and 36 were treated through a translumbar approach. Since the first transarterial embolization, when we began attempts to treat all patients initially via common femoral access, 58 (65.9%) of 88 patients were successfully embolized transarterially. All endoleaks in the translumbar group were successfully treated. At a median follow-up length of 15 weeks, a decrease or stabilization in aneurysm size was observed in 39 (73.6%) of the 53 endoleaks that had adequate follow-up computed tomography imaging. The overall residual endoleak rate was 34.0%. There was no difference in efficacy when comparing transarterial and translumbar approaches. We demonstrate that in most cases, transarterial access of the endoleak nidus is feasible, and controlled embolization is possible using EVOH. Furthermore, EVOH appears effective in long-term stabilization of aneurysm size and in preventing residual endoleaks.

Direct insertion of Amplatzer plugs to control lumbar arteries during open repair of type II endoleaks

Type II endoleak after endovascular repair of an infrarenal aortic aneurysm (EVAR) may be difficult to diagnose and treat in the best of circumstances. Management is more difficult in the patient with significant renal insufficiency. We report an 81-year-old man with stage IV chronic kidney disease and a rapidly expanding, asymmetric aortic aneurysm sac, 31 months after EVAR. A type II lumbar endoleak was diagnosed by duplex ultrasound imaging and managed successfully with open aortic exposure and direct insertion of Amplatzer plugs into two bleeding lumbar arteries due to complex anatomic factors.

Ischemic Colitis Following Transarterial Embolization for Type 2 Endoleak of EVAR: Report of a Case

A 71 year old man was diagnosed to have enlargement of abdominal aortic aneurysm due to type 2 endoleak two years after endovascular aneurysm repair (EVAR). 3D-CT demonstrated a type 2 endoleak that originated from the superior mesenteric artery that fed the inferior mesenteric artery and the right iliolumbar artery that flowed into the 4th lumbar artery. Transarterial embolization was performed by means of N-butyl-2-cyanoacrylate (NBCA). After the treatment, he suffered ischemic colitis that extended from the sigmoid colon to the descending colon. Conservative treatment was mainly performed, and clinical improvement was observed over time. He was discharged after 73 postoperative days.

Endovascular management of the patent inferior mesenteric artery in two cases of uncontrolled type II endoleak after endovascular aneurysm repair

Context:

Endovascular aneurysm repair (EVAR) has well documented advantages over traditional open repair and has been widely adopted as the alternative treatment modality for abdominal aortic aneurysm. However, endoleaks specifically type II can be a significant problem with this technique leading to aortic sac expansion and potential rupture. A large number of type II endoleaks are caused by persistent inferior mesenteric artery (IMA) retrograde bleeding. Various methods to try to manage this complication have been previously described. IMA embolization via the marginal artery of Drummond, however, has not been adequately popularized as an alternative less invasive approach to the treatment of type II endoleak.

Case Report:

Two men, ages 77 and 81, underwent uneventful EVAR for 5.5 and 5.0 cm infrarenal abdominal aortic aneurysms, respectively, using Zenith Cook^® bifurcated stent grafts. Computed tomography angiography at 1 and 6 months postoperatively demonstrated small type II endoleaks in both cases which were followed clinically. Subsequent follow-up tomography scan at 12 months revealed persistent type II endoleaks related to retrograde filling from the IMA with significant enlargement of the aneurysm sacs. Both patients underwent successful IMA coil embolization via the marginal artery of Drummond.

Conclusions:

Percutaneous IMA embolization using standard endovascular techniques to access the marginal artery of Drummond is an alternative, and in our opinion, preferred technique for controlling type II endoleaks caused by a persistently patent IMA.

Iatrogenic Ureteral Injury during Translumbar Embolization of a Type II Endoleak

The persistence of flow within an aneurysm sac remains the so-called Achilles heel of endovascular aortic aneurysm repair. The management of type II endoleaks remains controversial, although aneurysm sac expansion is an accepted indication for intervention. The present case describes a patient with a type II endoleak following endovascular repair of an abdominal aortic aneurysm treated by translumbar embolization. The procedure was complicated by iatrogenic injury to the left ureter and nontarget embolization resulting in acute ureteral obstruction.

Treatment of complications following endovascular repair of abdominal aortic aneurysms

Endovascular aneurysm repair (EVAR) is an important treatment option for abdominal aortic aneurysms, with lower perioperative morbidity and mortality rates than open surgical aneurysm repair. However, EVAR is associated with several unique complications that are not encountered with surgical repair such as endoleaks, graft migration, and renal artery occlusion. Preservation of the morbidity and mortality advantages of EVAR relies on the successful treatment of these complications by minimally invasive, endovascular approaches. Some of the techniques used to treat EVAR complications include balloon dilation and stenting, deployment of additional stent-graft pieces, coil embolization, and thrombolysis. Although the employment of these endovascular salvage techniques is common, data regarding their intermediate- to long-term efficacy is sparse, and further studies are needed to determine their efficacy in preventing conversion to open aneurysm repair and aneurysm rupture.

Endoscopic type 2 endoleak repair following endovascular aortic aneurysm repair: acute results and follow-up experience

The purpose of this study was to evaluate immediate and long-term results of endoscopic type 2 endoleak repair (EER) following endovascular abdominal aortic aneurysm repair. The basic methods include a retrospective review of electronic and paper medical records of patients admitted or referred to our institution for EER. Between July 1999 and October 2007, eight consecutive patients underwent EER. Mean operative time was 190 (104–355) min. One patient died preoperatively, due to profuse venous bleeding . One procedure was redone due to a missed pair of lumbar arteries. Mean hospital stay was five days (2–10). During mean follow-up, 50 months (29–91), one patient required additional coil embolization for a persistent type 2 endoleak. Four patients were diagnosed with a type 1 and one with a type 3 endoleak; three of these patients required an additional procedure. In conclusion, in this small series EER proved not to be beneficial.

Percutaneous transabdominal approach for the treatment of endoleaks after endovascular repair of infrarenal abdominal aortic aneurysm

Objective

The purpose of this study was to evaluate the technical feasibility and clinical efficacy of percutaneous transabdominal treatment of endoleaks after endovascular aneurysm repair.

Materials and Methods

Between 2000 and 2007, six patients with type I (n = 4) or II (n = 2) endoleaks were treated by the percutaneous transabdominal approach using embolization with N-butyl cyanoacrylate with or without coils. Five patients underwent a single session and one patient had two sessions of embolization. The median time between aneurysm repair and endoleak treatment was 25.5 months (range: 0-84 months). Follow-up CT images were evaluated for changes in the size and shape of the aneurysm sac and presence or resolution of endoleaks. The median follow-up after endoleak treatment was 16.4 months (range: 0-37 months)

Results

Technical success was achieved in all six patients. Clinical success was achieved in four patients with complete resolution of the endoleak confirmed by follow-up CT. Clinical failure was observed in two patients. One eventually underwent surgical conversion, and the other was lost to follow-up. There were no procedure-related complications.

Conclusion

The percutaneous transabdominal approach for the treatment of type I or II endoleaks, after endovascular aneurysm repair, is an alternative method when conventional endovascular methods have failed.

Type II endoleaks: when is intervention indicated and what is the index of suspicion for types I or III?

One of the principal reasons for failure of endovascular aneurysm repair (EVAR) is the occurrence of endoleaks, which regardless of size or type can transmit systemic pressure to the aneurysm sac. There is little debate that type I endoleaks (poor proximal or distal sealing) are associated with continued risk of aneurysm rupture and require treatment. Similarly, with type III endoleak, there is agreement that the defect in the device needs to be addressed; however, what to do with type II endoleaks and their effect on long-term outcome are not so clear. Aneurysm sac change is a primary parameter for determining the presence of an endoleak and assessing its impact. While diameter measurement has been the most commonly used method for determining sac changes, volume measurement has now been proven superior for monitoring structural changes in the 3-dimensional sac. Determining the source of an endoleak and the direction of flow are necessary for proper classification; however, while computed tomographic angiography has high sensitivity and specificity for detecting endoleaks, it is limited in its ability to show the direction of flow. Contrast-enhanced duplex ultrasound, on the other hand, is better able to quantify flow and characterize endoleaks. Flow is evidence of pressure, and increasing intrasac pressure increases wall tension, thus inducing progressive aneurysm expansion until rupture. Hence, determining intrasac pressure is becoming a vital component of endoleak assessment. All endoleaks can create systemic pressure inside the aneurysm sac, and there are a variety of intrasac pressure transducers being evaluated to assess this effect. A clinical pathway for patients with suspected type II endoleaks is based on a combination of imaging and pressure measurements. Imaging alone requires at least two interval examinations to determine the trend, while pressure measurements give immediate reassurance or an indication to intervene. Although still under development, pressure measurement is destined for general use and will provide a scientific basis for the management of type II endoleaks.

Type II endoleak after endovascular repair of abdominal aortic aneurysm: effectiveness of embolization

The purpose of this study was to report our experience in treating type II endoleaks after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms. Two hundred eighteen patients underwent EVAR with a Zenith stent-graft from January 2000 to December 2005. During a follow-up period of 4.5 + or - 2.3 years, solely type II endoleak was detected in 47 patients (22%), and 14 of them underwent secondary interventions to correct this condition. Ten patients had transarterial embolization, and four patients had translumbar/transabdominal embolization. The embolization materials used were coils, thrombin, gelatin, Onyx (ethylene-vinyl alcohol copolymer), and glue. Disappearance of the endoleak without enlargement of the aneurysm sac after the first secondary intervention was achieved in only five of these patients (5/13). One patient without surveillance imaging was excluded from analyses of clinical success. After additional interventions in four patients and the spontaneous disappearance of type II endoleak in two patients, overall clinical success was achieved in eight patients (8/12). One patient did not have surveillance imaging after the second secondary intervention. Clinical success after the first secondary intervention was achieved in two patients (2/9) in the transarterial embolization group and three patients (3/4) in the translumbar embolization group. The results of secondary interventions for type II endoleak are unsatisfactory. Although the small number of patients included in this study prevents reliable comparisons between groups, the results seem to favor direct translumbar embolization in comparison to transarterial embolization.

Endovascular repair of a spontaneous right common iliac artery--inferior vena cava fistula due to infrarenal aortoiliac aneurysm

Most abdominal aortic aneurysms are asymptomatic, but 1% to 4% of cases present with a life-threatening complication. A spontaneous right common iliac artery-inferior vena cava fistula, a rare condition caused by infrarenal aortoiliac aneurysm, is reported. In this case, the condition was successfully managed with primary endovascular stent-graft treatment.

Aneurysm Sac Pressure after EVAR: The Role of Endoleak

OBJECTIVE

The relation between endoleak and aneurysm sac pressure is not completely clear. This review evaluates the effect of endoleaks on aneurysm sac pressure and summarizes the present knowledge regarding aneurysm sac pressure after EVAR.

METHODS

A systematic search of literature was carried out using MEDLINE, EMBASE and Web of Science. Studies were included if aneurysm sac pressure measurements as well as systemic pressure measurements were performed during or after EVAR. Mean pressure indices (MPI), ratio mean aneurysm sac pressure to mean systemic pressure), in the absence of endoleaks and in the presence of different type of endoleaks were compared.

RESULTS

Stent-graft deployment does not seem to result in immediate reduction of aneurysm sac in the absence of an endoleak. Aneurysm sac pressure is elevated in the presence of an endoleak. However, the MPIs differ widely between studies both in the absence and presence of an endoleak.

CONCLUSION

MPI is not specific to the type of endoleak. This implies that the same type of endoleak does not necessarily pose the same MPI and by this the same hazard of aneurysm rupture, because the aneurysm sac pressure is directly related to the aneurysm wall stress.