Type-II endoleaks following endovascular AAA repair: preoperative predictors and long-term effects

Clinical and Radiological Outcomes of Accessory Renal Artery Exclusion during Endovascular Repair of Abdominal Aortic Aneurysms

BACKGROUND

Accessory renal arteries (ARAs) frequently coexist with abdominal aortic aneurysms (AAA) and can influence treatment. This study aimed to retrospectively analyze the ARA's exclusion effect on patients undergoing standard endovascular aneurysm repair for AAA.

METHODS

The study focused on medium- and long-term outcomes, including type II endoleak, aneurysmal sac changes, mortality, reoperation rates, renal function, and infarction post-operatively.

RESULTS

76 patients treated with EVAR for AAA were included. One hundred and two ARAs were identified: 69 originated from the neck, 30 from the sac, and 3 from the iliac arteries. The ARA treatment was embolization in 15 patients and coverage in 72. Technical success was 100%. One-month post-operative computed tomography angiography (CTA) revealed that 76 ARAs (74.51%) were excluded. Thirty-day complications included renal deterioration in 7 patients (9.21%) and a blood pressure increase in 15 (19.73%). During follow-up, 16 patients (21.05%) died, with three aneurysm-related deaths (3.94%). ARA-related type II endoleak (T2EL) was significantly associated with the ARA's origin in the aneurysmatic sac. Despite reinterventions were not significantly linked to any factor, post-operative renal infarction was correlated with an ARA diameter greater than 3 mm and ARA embolization.

CONCLUSION

ARAs can influence EVAR outcomes, with anatomical and procedural factors associated with T2EL and renal infarction. Further studies are needed to optimize the management of ARAs during EVAR.

Preoperative predictive factors for type II endoleak: Trying to define high-risk patients

OBJECTIVE

Type 2 endoleaks (T2E) continue to be the "Achilles Heel" of endovascular aneurysm repair (EVAR). The aim of this study is to analyze preoperative factors of patients who underwent EVAR to define risk factors for T2E.

METHODS

From January 2015 to June 2020, 140 of 191 patients who underwent EVAR in our institution meet inclusion criteria for this study. Postoperative image control were performed using duplex ultrasound or CT scan. All T2E detected during follow-up were confirmed by angio CT. Preoperative anatomic and clinical variables were analyzed for T2E using t-test, Mann-Whitney U test and Fisher exact test. ROC curves and the corresponding area under the curve (AUC) were used to describe the predictive accuracy for endoleak.

RESULTS

T2E was detected in 16 patients (11.43%)0.12 of them (75%) were persistent and 10 (62.5%) provoked sac enlargement. Predictive factors for T2E were a greater IMA diameter (2.5 ± 0.5 vs. 3.3 ± 0.5, p < 0.001) and an increasing number of LA (4.8 ± 1.6 vs. 6.7 ± 1.4, p < 0.001). ROC curve analysis stablished thresholds of 3.5 mm for IMA diameter (sensitivity 77%, specificity 86%) and 5.5 for patent LA (sensitivity 88%, specificity 59%) as risk factor to develop T2E.

CONCLUSIONS

Preoperative aortic side branches embolization to avoid T2E is not still standarised. We tried to define a group of high-risk patients for T2E. According to our findings, patients with a preoperative IMA> 3 mm and more than 5 patent LA should be considered for pre-EVAR embolization.

Predictive Factors and Strategies to Prevent the Development of Type 2 Endoleaks following Endovascular Aneurysm Repair

Type 2 endoleaks are a potential complication of endovascular aortic repair for abdominal aortic aneurysms. They are caused by vessels that have been excluded from the aorta lumen, but may still fill the aneurysm sac due to collateral filling. Type 2 endoleaks may lead to increased morbidity and need for additional procedures. Being able to identify patients at risk for Type 2 endoleaks and prevent them is important for any physician who is performing endovascular aortic repair.

Type II Endoleaks After EVAR: A Literature Review of Current Concepts

Endoleak is the most frequent complication following endovascular aneurysm repair, which is not present in the surgical counterpart. The most frequent type of endoleak corresponds to type II, and its natural history remains poorly understood. Therefore, their treatment continues to be a topic of debate. The vast majority of the studies found in the literature are of a retrospective nature, and there are no prospective studies comparing intervention versus a conservative approach. Future studies should aim to compare not only different approaches to resolve type II endoleak but also when should be the right time to treat them, with the primary purpose of avoiding sac rupture. The objective of this review is to provide the reader with a literature overview about type II endoleaks to help in the decision-making process on this topic.

Advanced monoenergetic reconstruction technique for dual-energy computed tomography to evaluate endoleaks after endovascular stent-graft placement

PURPOSE

To evaluate the usefulness of the advanced monoenergetic imaging (AMI) reconstruction technique for dual-energy computed tomography to evaluate endoleaks after endovascular stent-graft placement.

MATERIALS AND METHODS

Ninety-five dual-phase (early and delayed phases) enhanced CT examinations were performed for 60 patients who underwent endovascular stent-graft placement. AM images were reconstructed at 40 keV and compared with the standard 120-kVp images (SI). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the aorta and endoleak were measured. Two radiologists subjectively assessed endoleak delineation and contrast enhancement conditions using a 5-point Likert scale (1: poor-5: excellent).

RESULTS

Mean SNRs of the aorta were higher by AMI (early; 34.7 ± 10.2 [SD], delay; 11.4 ± 3.2) than by SI (early; 23.1 ± 6.3, delay; 8.6 ± 2.2) (P < 0.001). SNRs of the endoleak were higher by AMI (early; 26.3 ± 7.5, delay; 10.5 ± 3.1) than by SI (early; 18.2 ± 4.7, delay; 8.3 ± 2.1) (P < 0.001). CNRs by AMI (early; 32.9 ± 9.8, delay; 8.9 ± 2.8) were higher than those by SI (early; 19.5 ± 6.0, delay; 4.7 ± 1.6) in both phases (P < 0.001). Endoleak delineation and contrast enhancement conditions by AMI (4.4 ± 1.0 and 4.5 ± 0.6) were higher than those by SI (3.4 ± 1.0 and 3.3 ± 0.8) in the delayed phase (P < 0.001). There was no difference in the early phase.

CONCLUSION

AMI may be useful for evaluating endoleaks after endovascular stent-graft placement.

Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm: A Comprehensive Review

Abdominal aortic aneurysm (AAA) can be defined as an abnormal, progressive dilatation of the abdominal aorta, carrying a substantial risk for fatal aneurysmal rupture. Endovascular aneurysmal repair (EVAR) for AAA is a minimally invasive endovascular procedure that involves the placement of a bifurcated or tubular stent-graft over the AAA to exclude the aneurysm from arterial circulation. In contrast to open surgical repair, EVAR only requires a stab incision, shorter procedure time, and early recovery. Although EVAR seems to be an attractive solution with many advantages for AAA repair, there are detailed requirements and many important aspects should be understood before the procedure. In this comprehensive review, fundamental information regarding AAA and EVAR is presented.

Combined Type III and Type II Endoleaks after Endovascular Aneurysm Repair: Presentation of 2 Cases and a Literature Review

Although endovascular aneurysm repair is a feasible option for high-risk patients resulting in lower perioperative mortality when compared with open repair, the need for reintervention and long-term follow-up affects its use. The aim of the current report is to present 2 cases of patients with type IIIa endoleak from limb disconnection (one patient with double-bilateral endoleak) combined with a late type II endoleak and symptomatic sac growth treated in our department. We also performed a literature review about type III endoleaks and their treatment options.

Selective Inferior Mesenteric Artery Embolization during Endovascular Abdominal Aortic Aneurysm Repair to Prevent Type II Endoleak

PURPOSE

The purpose of this study was to evaluate the efficacy of simultaneous IMA (s-IMA) embolization during the endovascular abdominal aortic aneurysm repair (EVAR).

MATERIALS AND METHOD

From July 2007 to January 2011, 189 patients in the no embolization (NE) group underwent EVAR without the indication for s-IMA embolization. Since February 2011 to April 2014, 143 patients have undergone EVAR. Among these patients, 26 patients underwent s-IMA embolism under a predefined indication and constituted the simultaneous embolization (SE) group. The indications for s-IMA embolization were defined by preoperative computed tomography (CT) findings, as follows: (1) the diameter was greater than 2.5 mm and (2) no stenosis due to thrombus or calcification at its orifice.

RESULTS

The incidence of a type II endoleak from the IMA was 3.4% (5/143) in the SE group patients and 13.2% (25/189) in the NE group patients (p = 0.013), and the incidence of a type II endoleak from all branches (i.e., IMA, lumbar, medial sacral arteries) was 15.4% (22/143) in the SE group patients and 32.3% (61/189) in the NE group patients (p = 0.0003). During the follow-up period (range, 6-72 months; mean: 28 months), the reintervention rate for a type II endoleak from the IMA and/or other branches was 9.5% (18/189) in the NE group and 0.6% (1/143) in the SE group (p = 0.0001).

CONCLUSION

In selected patients, performing an s-IMA embolization, based on CT findings, decreased the incidence of a type II endoleak and reintervention from the IMA and from all branches.

Abdominal aortic aneurysms: pre- and post-procedural imaging

Abdominal aortic aneurysm (AAA) is a relatively common, potentially life-threatening disorder. Rupture of AAA is potentially catastrophic with high mortality. Intervention for AAA is indicated when the aneurysm reaches 5.0-5.5 cm or more, when symptomatic, or when increasing in size > 10 mm/year. AAA can be accurately assessed by cross-sectional imaging including computed tomography angiography and magnetic resonance angiography. Current options for intervention in AAA patients include open surgery and endovascular aneurysm repair (EVAR), with EVAR becoming more prevalent over time. Cross-sectional imaging plays a crucial role in AAA surveillance, pre-procedural assessment, and post-EVAR management. This paper will discuss the current role of imaging in the assessment of AAA patients prior to intervention, in evaluation of procedural complications, and in long-term follow-up of EVAR patients.

Risk factors of secondary intervention for type II endoleaks in endovascular aneurysm repair: An 8-year single institution study

BACKGROUND/OBJECTIVES

The natural history of type II endoleaks (T2ELs) is still not completely understood; however, it is widely accepted that those associated with aneurysmal sac growth are harmful. We aimed to review our experience with T2ELs in endovascular aneurysm repair (EVAR).

METHODS

We retrospectively reviewed electronic medical records of all patients who underwent EVAR for infrarenal-type abdominal aortic aneurysms (AAAs) at a single institution from August 2007 to November 2015. Demographic and clinical data were collected. Preoperative contrast computed tomography scans were reviewed to determine aneurysm morphology (the maximum AAA diameter, number of lumbar arteries that enter the AAA sac, size of the inferior mesenteric artery (IMA), proximal neck diameter, proximal neck angle, existence of thrombosis, presence of atheroma, and existence of rupture).

RESULTS

Sixty-two patients underwent EVAR; the follow-up duration was 35.82 ± 31.89 months. There were statistically significant differences in female sex (P = .040), number of lumbar arteries on preoperative computed tomography scans (P = .010), and non-smoking status (P = .031) between patients with and without T2ELs. There were statistically significant differences in the maximum AAA diameter (P = .034) and size of the IMA (P = .043) between patients with and without secondary intervention in T2EL. There was one mortality after EVAR but no mortality associated with T2ELs.

CONCLUSIONS

A more judicious approach that considers risk factors of T2ELs is needed before EVAR. The risk of secondary intervention in patients developing a T2EL after EVAR could increase with the maximum AAA diameter ≥7 cm or IMA ≥3 mm.

Abdominal Aortic Aneurysm Type II Endoleaks

Type II endoleaks occur commonly following endovascular aneurysm repair (EVAR). Although they remain enigmatic, multiples studies have evaluated preoperative risk factors and strategies for prevention of type II endoleaks. Prophylactic treatment of type II endoleaks can include embolization of accessory arteries, as well as complete aneurysmal sac occlusion. Regular post-operative surveillance and screening for type II endoleaks with triple-phase CTA is the standard of care. Aneurysm size and growth rate are factors that predict whether a persistence type II endoleak is hemodynamically significant, and whether it requires treatment with percutaneous trans-lumbar or trans-arterial embolization techniques. Less commonly, type II endoleaks can be repaired using laparoscopic or open surgical ligation of feeder arterial branches. Emerging methods using endovascular aneurysm sac sealing technology may continue to alter the incidence and long-term management strategies of type II endoleaks. Here we review the latest strategies in the treatment of Type II endoleaks following EVAR.

Embolization of Onyx Causing Acute Limb Ischemia

We present the case of a patient with a refractory type II endoleak treated with translumbar Onyx with passage of the Onyx material into the endograft and subsequent embolization to the infrainguinal vasculature. This report represents a new complication of Onyx embolization that, to our knowledge, has not previously been described in the literature.

Stent Grafts for Thoracic Aortic Pathology: Single-Center Experience in Western Australia

The purpose of this article is to report a single-center experience in treating thoracic aortic pathology with stent grafts. This is a retrospective review of cases done within a period of 30 months.

Between January 2002 and May 2004, 12 patients were treated in our institution with thoracic stent grafts ( n = 12) for various clinical conditions. There were seven men and five women. Three patients required emergency treatment ( n = 3), two for aortic transection and one for iatrogenic injury during lung biopsy. Others were treated electively ( n = 9).

All patients were high risk for open surgery. There was one perioperative death, with a patient with multiple trauma succumbing to head injury 4 weeks after stent graft insertion. There was no incidence of paraplegia. Three patients underwent bypass surgery in the neck to achieve an adequate proximal seal zone prior to stent grafting. One patient with an aneurysm of the descending thoracic aorta required an extension limb below the original graft for an increase in sac size, possibly owing to endotension. Renal failure occurred in one patient and resolved without dialysis. One patient died 18 months after her procedure, possibly owing to aneurysm expansion.

Stent grafts are a viable alternative to open surgery for thoracic aortic pathology in high-risk individuals. Visceral and spinal cord ischemia is less prevalent with stent grafts compared with open surgery. The short-term results are promising. Long-term follow-up is awaited. Stent grafts might have greater impact in the thoracic aorta than the abdominal aorta for which they were initially developed.

The Influence of Preoperative Aneurysmal Thrombus Quantity and Distribution on the Development of Type II Endoleaks with Aneurysm Sac Enlargement After EVAR of AAA

PURPOSE

To determine the influence of preoperative aneurysmal thrombus quantity and distribution on the development of type II endoleak with aneurysm sac enlargement after endovascular aneurysm repair (EVAR).

MATERIALS AND METHODS

We retrospectively analyzed the pre- and postoperatively performed CT scans of 118 patients who had follow-up imaging for at least 1 year after EVAR available. We assessed preoperative thrombus perimeter (T Peri), diameter (T Dia), cross-sectional area (T CSA), and volume (T Vol). The preoperative thrombus distribution was classified into no thrombus, semilunar-shaped (anterior, right side, left side, posterior) thrombus, and circumferential type thrombus. The number of preoperative patent aortic side branches (ASB) was identified. Endpoint was type II endoleak with aneurysm volume (A Vol) increase of ≥5 % during follow-up.

RESULTS

During follow-up (2 years, range 1-9 years), 17 patients with type II endoleak had significant A Vol increase. Less preoperative T Peri, T Dia, T CSA, and T Vol were associated with A Vol increase. A circumferential thrombus distribution significantly protected against aneurysm enlargement (p = 0.028). The variables with the strongest significance for A Vol increase were preoperative T Vol/A Vol ratio (OR 0.95; p = 0.037) and number of patent ASB (OR 3.52; p < 0.001).

CONCLUSION

A low preoperative T Vol/A Vol ratio and a high number of patent ASB were associated with aneurysm sac enlargement after EVAR.

Type 2 Endoleaks: The Diagnostic Performance of Non-Specialized Readers on Arterial and Venous Phase Multi-Slice CT Angiography

Purpose

To define the diagnostic precision of non-specialized readers in the detection of type 2 endoleaks (T2EL) in arterial versus venous phase acquisitions, and to evaluate an approach for radiation dose reduction.

Methods

The pre-discharge and final follow-up multi-slice CT angiographies of 167 patients were retrospectively analyzed. Image data were separated into an arterial and a venous phase reading set. Two radiology residents assessed the reading sets for the presence of a T2EL, feeding vessels, and aneurysm sac size. Findings were compared with a standard of reference established by two experts in interventional radiology. The effective dose was calculated.

Results

Overall, experts detected 131 T2ELs, and 331 feeding vessels in 334 examinations. Persistent T2ELs causing aneurysm sac growth > 5 mm were detected in 20 patients. Radiation in arterial and venous phases contributed to a mean of 58.6% and 39.0% of the total effective dose. Findings of reader 1 and 2 showed comparable sensitivities in arterial sets of 80.9 versus 85.5 (p = 0.09), and in venous sets of 73.3 versus 79.4 (p = 0.15), respectively. Reader 1 and 2 achieved a significant higher detection rate of feeding vessels with arterial compared to venous set (p = 0.04, p < 0.01). Both readers correctly identified T2ELs with growing aneurysm sac in all cases, independent of the acquisition phase.

Conclusion

Arterial acquisitions enable non-specialized readers an accurate detection of T2ELs, and a significant better identification of feeding vessels. Based on our results, it seems reasonable to eliminate venous phase acquisitions.

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.

Open Surgical Repair Can Be One Option for the Treatment of Persistent Type II Endoleak after EVAR

PURPOSES

Endovascular abdominal aortic aneurysm repair (EVAR) is an increasingly used method of repairing abdominal aortic aneurysm (AAA). However, the treatment of persistent type II endoleak is still a controversial issue. Five cases are reported here in which we performed open surgical repair of growing aneurysm due to persistent type II endoleak.

METHOD

Totally 128 EVAR cases were retrospectively reviewed, which were operated in our hospital from April 2008 to October 2013. These cases were followed by periodical contrast-enhanced computed tomography (CT) after EVAR. When persistent type II endoleak caused aneurysm sac growth, we performed surgical repair method for the first line treatment. In the operation, we incised the aneurysm sac by abdominal small median incision approach and sutured lumber arteries from inside of aneurysm sac and tied inferior mesenteric artery (IMA) in addition to aneurysmorrhaphy. Contrast-enhanced CT scanning was performed in a week after open repair for the confirmation of complete treatment.

RESULTS

Five of 128 cases (3.9%) were needed to be surgically repaired because of aneurysm sac growth (>5 mm), including two ruptured AAA cases. All patients recovered uneventfully. Contrast-enhanced CT scanning performed a week after these operations showed no endoleak and intact stent grafts and reduction of the aneurysm size.

CONCLUSION

We believe open surgical repair method of persistent type II endoleak with aneurysm expansion is secure method, and can be one of the preferable options for this life threatening complication after EVAR.

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.

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.

Management of a right aberrant subclavian artery during complex hybrid stent-graft procedures: a rare and complex issue

A 76-year-old man with an ascending arch and proximal descending aortic aneurysm underwent a complex aortic replacement through a sternotomy with ligation of a right aberrant subclavian artery (RASA) distal to the right vertebral artery. The second-stage procedure was performed with a stent-graft deployed within the elephant trunk. At 6- and 12-month follow-up, the RASA was opacified by the patent right vertebral artery. Under ultrasound guidance, the patient's RASA stump was occluded by coils. Management of an RASA during complex hybrid stent-graft procedures is discussed.

Static sac size with a type II endoleak post-endovascular abdominal aortic aneurysm repair: surveillance or embolization?

A best evidence topic was written according to a structured protocol. The question addressed was whether embolization is superior to surveillance for a type II endoleak associated with a static sac size post-endovascular abdominal aortic aneurysm repair (EVAR). Four hundred and sixty-one papers were identified, of which 10 papers presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, and relevant outcomes and results are tabulated. A review of the available literature suggests that most type II endoleaks are innocuous and will seal spontaneously during the long-term follow-up, even when they persist for more than 6 months. An analysis of the large European Collaborators on Stent-Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) registry that includes prospective data on 2463 patients from 87 European hospitals showed that type II endoleaks were not associated with an increased risk of rupture; this correlates well with the large single-centre studies included in this review. Based on the available evidence, we conclude that the management of most isolated type II endoleaks should be conservative-with close radiological follow-up--even when persistent, with intervention restricted to theoese associated with sac enlargement >5 mm over a 6-month period or >10 mm when compared with pre-EVAR diameter.

Prevention of type II endoleak by laparoscopic inferior mesenteric artery ligation

Abdominal aortic aneurysm repair by endovascular techniques have gained wide acceptance as a treatment option. A potential well-known complication of endovascular repair includes endoleak. Specifically, type II endoleak, which is described as retrograde flow into the aneurysm sac through collateral vessels, can occur in up to 30% of patients. Certain preoperative factors can predict which patients may develop type II endoleak. This article describes laparoscopic inferior mesenteric artery ligation prior to endovascular abdominal aortic aneurysm repair as a viable treatment option in the prevention of type II endoleak.

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.

[Imaging of endoleaks after endovascular aneurysm repair (EVAR) with contrast-enhanced ultrasound (CEUS)]

Endoleaks following endovascular aneurysm repair (EVAR) are common and present a diagnostic challenge in the follow-up after EVAR. Contrast-enhanced ultrasound (CEUS) is a promising new method for the diagnosis and follow-up of endoleaks. CEUS with SonoVue allows a rapid and non-invasive diagnosis in the follow-up after EVAR. The sensitivity and specificity of conventional ultrasound compared to the multislice CT angiography is estimated to be 33-63% and 63-93%, respectively. These values can be increased through the use of CEUS in up to 98-100% (sensitivity) and 82-93% (specificity). This article describes the etiology, classification and importance of different types of endoleaks. The value of CEUS in this clinical scenario will be discussed.

Intraoperative Endoleak During EVAR: Frequency, Nature, and Significance

Objective: Endoleaks are critical complications of endovascular abdominal aortic aneurysm repair (EVAR). This study sought to determine the frequency and nature of intraoperative endoleaks and their impact on postoperative endoleak-related events. Methods: A retrospective chart review was performed of all patients who underwent EVAR at our institution. The impact of intraoperative endoleaks on postoperative endoleak rates and endoleak-related reintervention rates were assessed. Results: From December 18, 1996, to May 21, 2003, 241 patients underwent EVAR. An endoleak was observed during 126 (52.3%) procedures. Type I endoleaks were observed in 63 (26.1%) cases: 35 proximal and 31 distal endoleaks (3 cases at both attachments). Angioplasty, additional cuff placement, or stenting corrected 59 (89.4%) of these endoleaks. A total of 71 type II intraoperative endoleaks (29.5%) and 8 type IV endoleaks (3.3%) were observed without any attempted corrective maneuvers. Ten type III endoleaks (4.2%) occurred but all resolved with angioplasty or additional cuff placement. In all, 86 (35.7%) endoleaks persisted on completion angiogram. Patients with a type I or type II intraoperative endoleak were more likely to have an endoleak at 1.5 years (31.4% vs. 21.6%, P = .018). Reinterventions were required more often after an intraoperative type I endoleak (10% vs. 4%, P = .003). Patients with intraoperative endoleaks demonstrated a trend toward less postoperative aneurysm diameter reduction at 2 years (43.8% vs. 74.5%, P = .104). Conclusion: The presence of a type I or a type II endoleak during EVAR significantly increases the likelihood of a postoperative endoleak and should prompt a high degree of suspicion during follow-up.

Endovascular aneurysm repair: current and future status

Endovascular aneurysm repair has rapidly expanded since its introduction in the early 1990s. Early experiences were associated with high rates of complications including conversion to open repair. Perioperative morbidity and mortality results have improved but these concerns have been replaced by questions about long-term durability. Gradually, too, these problems have been addressed. Challenges of today include the ability to roll out the endovascular technique to patients with adverse aneurysm morphology. Fenestrated and branch stent-graft technology is in its infancy. Only now are we beginning to fully understand the advantages, limitations, and complications of such technology. This paper outlines some of the concepts and discusses the controversies and challenges facing clinicians involved in endovascular aneurysm surgery today and in the future.

Persistent type 2 endoleak after endovascular repair of abdominal aortic aneurysm is associated with adverse late outcomes

OBJECTIVE

Type 2 endoleak occurs in up to 20% of patients after endovascular aneurysm repair (EVAR), but its long-term significance is debated. We reviewed our experience to evaluate late outcomes associated with type 2 endoleak.

METHODS

During the interval January 1994 to December 2005, 873 patients underwent EVAR. Computed tomography (CT) scan assessment was performed < or =1 month of the operation and at least annually thereafter. Sequential 6-month CT scan follow-up was adopted for those patients with persistent type 2 endoleaks, and reintervention was limited to those with sac enlargement >5 mm. Study end points included overall survival, aneurysm sac growth, reintervention rate, conversion to open repair, and abdominal aortic aneurysm (AAA) rupture. Preoperative variables and anatomic factors potentially associated with these endpoints were assessed using multivariate analysis.

RESULTS

We identified 164 (18.9%) patients with early (at the first follow-up CT scan) type 2 endoleaks. Mean follow-up was 32.6 months. In 131 (79.9%) early type 2 endoleaks, complete and permanent leak resolution occurred < or =6 months. Endoleaks persisted in 33 patients (3.8% of total patients; 20.1% of early type 2 endoleaks) for >6 months. Transient type 2 endoleak (those that resolved < or =6 months of EVAR) was not associated with adverse late outcomes. In contrast, persistent endoleak was associated with several adverse outcomes. AAA-related death was not significantly different between patients with and without a type 2 endoleak (P = .78). When evaluating patients with no early endoleak vs persistent endoleak, freedom from sac expansion at 1, 3, and 5 years was 99.2%, 97.6%, and 94.9% (no leak) vs 88.1%, 48.0%, and 28.0% (persistent) (P < .001). Patients with persistent endoleak were at increased risk for aneurysm sac growth vs patients without endoleak (odds ratio [OR], 25.9; 95% confidence interval [CI] 11.8 to 57.4; P < .001). Patients with a persistent endoleak also had a significantly increased rate of reintervention (OR, 19.0; 95% CI, 8.0 to 44.7); P < .001). Finally, aneurysm rupture occurred in 4 patients with type 2 endoleaks. Freedom from rupture at 1, 3, and 5 years for patients with a persistent type 2 endoleak was 96.8%, 96.8%, and 91.1% vs 99.8%, 98.5%, and 97.4% for patients without a type 2 endoleak. Multivariate analysis demonstrated persistent type 2 endoleak to be a significant predictor of aneurysm rupture (P = .03).

CONCLUSIONS

Persistent type 2 endoleak is associated with an increased incidence of adverse outcomes, including aneurysm sac growth, the need for conversion to open repair, reintervention rate, and rupture. These data suggest that patients with persistent type 2 endoleak (>6 months) should be considered for more frequent follow-up or a more aggressive approach to reintervention.

An 8-year experience with type II endoleaks: Natural history suggests selective intervention is a safe approach

OBJECTIVE

The treatment of type II endoleaks remains controversial because little is known about their long-term natural history and impact on changes in aneurysm morphology. This study reviews type II endoleaks occurring in patients after endovascular abdominal aortic aneurysm repair (EVAR) at a single-institution over an 8-year period.

METHODS

All patients undergoing EVAR who had type II endoleaks documented on follow-up imaging studies at our institution between January 1997 and March 2005 were reviewed. Data regarding patient demographics in addition to aneurysm size, device type, operative complications, and secondary interventions were reviewed. Outcomes evaluated included the rate of spontaneous sealing, freedom from secondary intervention, and aneurysm enlargement, rupture, or conversion.

RESULTS

Type II endoleaks were present in 154 of 965 patients (16.0%) undergoing EVAR. Mean follow-up time was 22.0 months (range, 1 to 72 months). Fifty-five patients (35.7%) with type II endoleaks sealed spontaneously in a mean time of 14.5 months. According to Kaplan-Meier analysis, approximately 75% of type II endoleaks sealed spontaneously within a 5-year period. Nineteen patients (12.3%) with type II endoleaks were treated at a mean time of 19.9 months at the operating surgeon's discretion, including 13 with sac enlargement >5 mm. Kaplan-Meier analysis estimated that approximately 65% of the patients remained free of intervention after a period of 4 years. Thirteen patients (8.4%) experienced aneurysm sac enlargement >5 mm. Kaplan-Meier analysis estimated that approximately 80% of patients with type II endoleaks remained free of sac enlargement >5 mm over a 4-year period. No patients with type II endoleaks experienced rupture or required conversion to open repair during their follow-up. Cox regression analysis showed that cancer, coronary artery disease, and chronic obstructive pulmonary disease were associated with earlier spontaneous closure of the type II endoleaks (P < .05).

CONCLUSIONS

We observed that type II endoleaks have a relatively benign course, and in the absence of sac expansion, can be followed for a prolonged course of time without the need for intervention. The rate of spontaneous seal continues to increase with time and, therefore, close follow-up of patients with type II endoleaks who show no signs of aneurysm expansion is a safe approach. For patients in whom the exact etiology of their endoleak is in question, dynamic imaging should be used to exclude the presence of a type I endoleak.

The importance of iliac fixation in prevention of stent graft migration

OBJECTIVE

Secure proximal fixation of endografts to the infrarenal aortic neck is known to be important in the short- and long-term success of endovascular aneurysm repair. We sought to determine the relative importance of distal iliac fixation in preventing endograft migration and adverse clinical events after endovascular aneurysm repair.

METHODS

We reviewed the outcome of 173 patients treated from 1996 to 2003 at Stanford University Medical Center with an externally supported stent graft. Quantitative image analysis of the postimplantation computed tomography scan was performed to determine the proximal aortic and distal iliac fixation lengths and the proximity the distal end of the stent graft to the iliac bifurcation. Subsequent follow-up computed tomography scans were reviewed for evidence of stent graft migration. Patients were grouped according to good (>15 mm), intermediate, or bad (<10 mm) aortic fixation and good (iliac fixation length > or =25 mm and iliac limbs <10 mm from iliac bifurcation), intermediate, or bad (<25-mm fixation length) iliac fixation.

RESULTS

Stent graft migration of 10 mm or more was seen in 17 patients (10%) during the 23 +/- 19-month follow-up period. Patients with no migration had a greater iliac fixation length (30 +/- 12 mm) than those with migration (22 +/- 8 mm; P = .01), and the distal ends of the iliac limbs were closer to the iliac bifurcation (15 +/- 12 mm) than in patients with migration (25 +/- 10 mm; P < .001). Patients with no migration also had a greater proximal aortic fixation length (23 +/- 12 mm) than migration patients (13 +/- 7 mm; P = .001). There were no migrations among patients with good iliac fixation whether aortic fixation was good, intermediate, or bad (0/63; 0%). Among patients with bad/intermediate iliac and good aortic fixation, there were 5 (9%) of 58 patients had migrations. Patients with both bad/intermediate iliac and bad/intermediate aortic fixation had the highest migration rate (12/52; 23%). Cox proportional hazards regression modeling revealed that the significant factors predicting migration were poor proximity of the distal end of the iliac limbs to the iliac bifurcation (odds ratio 17.2; P = .01) and aortic fixation length (odds ratio 2.0; p = 0.007 for each centimeter). Iliac extender modules were placed in 9 patients with bad iliac fixation and migration, with no further migration during a mean follow-up of 12 months. Patients with good iliac and aortic fixation and no endoleak on the initial postprocedure computed tomography scan (n = 43) had no migrations, secondary procedures, or adverse clinical events over a 2-year follow-up period.

CONCLUSIONS

Iliac fixation, along with proximal aortic fixation, is an important factor in preventing the migration of stent grafts that have longitudinal columnar support. Patients with good iliac fixation did not experience migration even in the presence of suboptimal proximal aortic fixation. Close proximity of the distal end of the stent graft to the iliac bifurcation seems to provide stability against migration.

Computed tomography versus magnetic resonance imaging of endoleaks after EVAR

AIM

The aim of study was to compare the sensitivity of MRI and CTA for endoleak detection and classification after EVAR.

PATIENTS & METHODS

Twenty-eight patients, between 2 days and 65 months after EVAR, were evaluated with both CT and MRI. Twenty-five patients had an Ancure graft and the other three had an Excluder. The MRI protocol for endoleak evaluation included: a T1-weighted spin echo, a high-resolution 3D CE-MRA, and a post-contrast T1-weighted spin echo. In total 40 ml Gadolinium was administered. The CT protocol consisted of a blank survey followed by a spiral CT angiography (CTA) using 140 ml of Ultravist. An experienced, blinded observer evaluated all CTs and MRIs.

RESULTS

Using MRI and MRA techniques significantly more endoleaks (23/35) were detected than with CTA (11/35) (p=0.01, Chi-Square). CT could not determine the type of endoleak in 3 of the 11 endoleaks detected and was uncertain in one. MRI was uncertain about the type in 14 of the 23 endoleaks detected. All endoleaks visible on CT were visible by MRI as well.

CONCLUSIONS

MRI techniques are more sensitive for the detection of endoleak after endovascular AAA repair than CT.

Characterization of retrograde collateral (type II) endoleak using a new canine model

OBJECTIVE

The clinical significance of retrograde collateral arterial perfusion of abdominal aortic aneurysms after endovascular repair (type II endoleak) has not been completely characterized. In this study a canine model was used to analyze intra-aneurysmal pressure, thrombus histologic characteristics, endoleak patency, and radiographic appearance of type II endoleaks originating from single and multiple aneurysm side branches.

METHODS

Prosthetic aneurysms with an intraluminal solid-state strain-gauge pressure transducer were created in the infrarenal aorta of 14 mongrel dogs. A single collateral side branch was reimplanted in 4 animals, multiple side branches were reimplanted in 6 animals, and no side branches were reimplanted in 4 control animals. Intra-aneurysmal and systemic pressure was measured for 60 to 90 days after creation of the type II endoleak. Endoleak patency and flow were assessed with duplex ultrasound scanning and cine-magnetic resonance angiography. Histologic analysis of the intra-aneurysmal thrombus was also performed.

RESULTS

Stent-graft exclusion reduced intra-aneurysmal pressure significantly in all animals, as compared with systemic pressure (P < .001). All intra-aneurysmal pressure values are indexed to the systemic pressure, and are represented as a percentage of the simultaneously obtained systemic pressure, which has a value of 1.0. Type II endoleaks originating from multiple side branches exhibited significantly increased intra-aneurysmal systolic pressure, mean pressure, and pulse pressure, as compared with endoleaks derived from either a single side branch (systolic pressure: multiple, 0.70 +/- 0.28 vs single, 0.50 +/- 0.19; P < .001; mean pressure: multiple, 0.78 +/- 0.23 vs single, 0.59 +/- 0.22, P < .001; pulse pressure: multiple, 0.41 +/- 0.25 vs single, 0.17 +/- 0.15, P < .001) or excluded control aneurysms that had no side branches and no endoleak (systolic pressure, 0.17 +/- 0.09; mean pressure, 0.14 +/- 0.10; pulse pressure, 0.098 +/- 0.08; P < .001). Cine-magnetic resonance angiograms and duplex ultrasound scans documented persistent patency of multiple branch endoleaks up to the time of euthanasia. In contrast, single side branch endoleaks thrombosed within 3 days (P < .001). Thrombus in the aneurysm sac in close proximity to the endoleak contained intact red blood cells and limited fibrin. Thrombus distant from the endoleak demonstrated extensive fibrin deposition and degraded red blood cells.

CONCLUSION

The canine model may be used to reliably measure intra-aneurysmal pressure in the presence of patent and thrombosed type II endoleaks. In this model 2 or more side branches are necessary to maintain persistent patency of type II endoleaks. These endoleaks are associated with significantly elevated intra-aneurysmal pressure, that is, 70% to 80% of systemic pressure. These results suggest that persistent type II endoleaks have clinical significance.

CLINICAL RELEVANCE

Endoleaks originating from retrograde flow in the side branch vessels of the aneurysm generate significant levels of intra-aneurysmal pressure, that is, 70% to 80% of systemic pressure. At least 2 patent side branch vessels appear to be necessary to cause persistent patency of type II endoleak in the canine model. Further studies will be necessary to enable more complete characterization of retrograde endoleaks and to extend these findings to allow clinical application. However, these results suggest that persistently patent type II endoleaks are clinical significance and may require more intensive follow-up intervention.

Effectiveness of coiling in the treatment of endoleaks after endovascular repair

BACKGROUND

Persistent endoleaks are a common problem following endovascular repair of abdominal aortic aneurysms, and the best method of treatment has been an issue of debate. Some experimental evidence has suggested that coiling may not be an effective method because it allows transmission of pressure across the coils with continued expansion of the sac. We reviewed our experience with endoleak coiling to assess the degree of clinical success of this treatment.

METHODS

A retrospective review of patients with type I or type II endoleaks treated solely by coiling over a 7-year period (1997-2003) was performed. All endoleaks had been observed for at least 6 months prior to intervention to detect spontaneous resolution. All coils were delivered by selective catheterization of the endoleaks. For Type II endoleaks, the branches were all coiled at their junction with the sac when feasible and the endoleak cavity was packed. Clinical success was defined as cessation of endoleak on follow-up computed tomography as well as no further aneurysmal growth (> or =5mm minor axis).

RESULTS

Twenty-eight patients had their endoleaks treated only with coils. There were 22 Ancure, 2 Excluder, 2 AneuRx, and 2 Lifepath endografts in this patient cohort. Procedural morbidity was 0%. Mean follow-up after coiling for all patients was 18 months (range, 1-60 months) while mean follow-up for patients with a type I endoleak was 24 months. Clinical success was achieved in 15 of 19 (79%) patients with type II endoleaks and 8 of 9 (89%) patients with type I. Three patients, all with type I endoleak, required more than 1 episode of coiling, while 2 others, both with type II lumbar endoleaks, required repeat angiography due to inability to access the leak during the first attempt. There were 2 proximal and 6 distal type I endoleaks (2 aortic, 6 iliac) successfully treated while the type II successes included 8 inferior mesenteric artery and 7 sole lumbar endoleaks. Five patients continued to show evidence of endoleak over time: 2 endoleaks were associated with aneurysm growth leading to conversion in 1 patient, 2 patients with type II endoleaks are stable, and the sole type I endoleak with continued perigraft flow has shown significant shrinkage of the sac and continues to be observed 18 months later. No ruptures were noted during follow-up.

CONCLUSION

Coiling as the sole method of endoleak management may be a suitable treatment option in selected patients. Clinical success can be expected in over 80% of patients with type II and select type I endoleaks, with minimal morbidity.

Intra-aneurysm sac pressure measurements after endovascular aneurysm repair: differences between shrinking, unchanged, and expanding aneurysms with and without endoleaks

OBJECTIVE

Our objective was to study intra-aneurysm pressure after endovascular aneurysm repair (EVAR) in shrinking, unchanged, and expanding abdominal aortic aneurysms (AAAs) with and without endoleaks.

METHODS

Direct intra-aneurysm sac pressure measurement (DISP) by percutaneous translumbar puncture of the AAA under fluoroscopic guidance was performed 46 times during the follow-up of 37 patients (30 men; median age, 73 years [range, 58-82 years]; AAA diameter: median, 60 mm [range, 48-84 mm]). Three patients were included in two different groups because DISP was performed more than once with different indications. Tip-pressure sensors mounted on 0.014-inch guidewires were used for simultaneous measurement of systemic and AAA sac pressures. Mean pressure index (MPI) was calculated as the percentage of mean intra-aneurysm pressure relative to the simultaneous mean intra-aortic pressure.

RESULTS

Median MPI was 19% in shrinking (11 patients), 30% in unchanged (10 patients), and 59% in expanding (9 patients) aneurysms without endoleaks. Pulse pressure was also higher in expanding (10 mm Hg) compared with shrinking (2 mm Hg; P <.0001) AAAs. Four of the nine patients with expanding AAAs underwent five repeated DISPs later in the follow-up, and MPIs were consistently elevated. Seven of the 10 patients with unchanged AAAs without endoleaks underwent further computed tomography follow-up after DISP; 2 expanded (MPI, 47%-63%), 4 shrank (MPI, 21%-30%), and 1 remained unchanged (MPI, 14%). Type II endoleaks (6 patients, 7 DISPs) were associated with wide range of MPI (22%-92%). Successful endoleak embolization (n = 4) resulted in pressure reduction.

CONCLUSIONS

Intra-aneurysm sac pressure measurement is an important adjunctive for EVAR evaluation, possibly allowing early detection of failures. High pressure is associated with AAA expansion and low pressure with shrinkage. Type II endoleaks can be responsible for AAA pressurization, and successful embolization appears to result in pressure reduction.

Volume regression of abdominal aortic aneurysms and its relation to successful endoluminal exclusion

OBJECTIVES

Evaluating the success of endoluminal repair of abdominal aortic aneurysms (AAAs) is frequently based on diameter measurements and determining the presence of endoleaks. The use of three-dimensional volumetric data and observation of morphologic changes in the aneurysm and device have been proposed to be more appropriate for postdeployment surveillance. The purpose of this study was to analyze the long-term volumetric and morphologic data of 161 patients who underwent endovascular AAA exclusion and to assess the utility of volume measurements for determining successful AAA repair.

METHODS

Patients with spiral computed tomography scans obtained preoperatively, within the first postoperative month, at 6 months, and annually thereafter, were included in this analysis. Computerized interactive three-dimensional reconstruction of each AAA scan was performed. Total aneurysm sac volume was measured at each time interval (mean preoperative volume 169.0 +/- 78.5 mL), and the significance of volume changes was determined by mixed linear modeling, a form of repeated measures analysis, to account for longitudinal data clustered at the individual level. Sixty-two patients (38%) developed endoleaks at some time during follow-up-15 type I leaks, 45 type II leaks, and 2 type III leaks. The patients with type I and type III leaks were treated with cuffs, and the type II leaks were treated either with observation, side-branch embolization, or required open conversion.

RESULTS

Aneurysm sac volume increased slightly at 1-month follow-up (+3.3%), and then decreased steadily to -12.9% at 5 years (P <.0001). This effect remained unchanged after controlling for the three device types used in our study population. Patients who did not exhibit an endoleak (n = 99) showed a significant decrease in aneurysm volume across the entire follow-up duration when compared with those who did exhibit an endoleak (n = 62) (P <.0001). The presence of a 10% or greater decrease in volume at 6 months demonstrated a sensitivity of 64%, a specificity of 95%, a positive predictive value of 95%, a negative predictive value of 62%, and an accuracy of 75% for predicting primary clinical success defined by successful deployment of the device; freedom from aneurysm- or procedure-related death; freedom from endoleak, rupture, migration, or device malfunction; or conversion to open repair.

CONCLUSIONS

Volumetric analysis may be used to predict successful endoluminal exclusion of AAAs. Volume regression appears to be device-independent and should be expected in most clinically successful cases. The presence of volume increases in the first 6 months is suspicious for an endoleak that is pressurizing the aneurysm sac and heralds the need for closer evaluation and possible intervention. A volume decrease of 10% or greater at 6 months and continuing regression over time is associated with successful endovascular repair.

Distribution of sac pressure in an experimental aneurysm model after endovascular repair: the effect of endoleak types I and II

PURPOSE

To study in an experimental aneurysm model the differential distribution of strain/pressure (S/P) on the aneurysm wall before and after endograft exclusion and in the presence of individual type I and type II endoleaks.

METHODS

Two tapered elliptical Gore-Tex patches were sutured to an anterior and posterior longitudinal arteriotomy of an 8-mm Gore-Tex tube graft, thus creating a fusiform aneurysm. Two S/P transducers were placed at the proximal sac adjacent to the proximal neck, 2 at the site of the widest sac diameter, and 2 at the sac adjacent to the distal neck. The aneurysm, which was connected to a pulsatile pump system, was excluded using a 10-mm endograft. Type I and type II endoleaks were created and tested individually. S/P measurements were obtained at systemic systolic pressures (BP) of 80, 110, and 150 mmHg. Thrombosis of the sac contents was induced by injection of thrombin and calcium in the sac. Angiography was used to verify presence or absence of flow in the sac.

RESULTS

Aneurysm exclusion resulted in significant S/P reductions at all 3 BP levels versus prior to exclusion (p<0.05). Thrombus in the sac did not alter S/P in the excluded sac (p>0.05 for all 3 BP levels). In the presence of a proximal type I endoleak, S/P distribution was not uniform, and S/P at the proximal neck was close to S/P prior to exclusion (p>0.05 no graft versus type I endoleak for all 3 BP levels). This was also true in the presence of thrombus. With a type II endoleak, S/P was more evenly distributed and was not significantly elevated compared to the pressure without an endoleak (p>0.05, graft versus type II endoleak for all 3 BP levels). Thrombus had no effect on intrasac S/P with a type II endoleak. Intrasac S/P was significantly higher in the presence of a type I endoleak compared to a type II endoleak when BP=150 mmHg (p=0.008).

CONCLUSIONS

Endovascular exclusion of an aneurysm results in uniform S/P reduction in the aneurysm sac. Type I endoleak, but not type II endoleak, results in significantly higher S/P in an area of the sac adjacent to the proximal neck. Thrombus does not result in significantly different S/P distribution in the aneurysm sac.