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PURPOSE The optimal modality for following aneurysm size and detecting endoleaks after endovascular aneurysm repair (EVAR) remains controversial. Computed tomographic angiography (CTA) has been widely employed but can be limited by metal artifact from stents, which is exacerbated by embolization coils placed during the treatment of type 2 endoleaks. The authors assessed interobserver agreement of CTA for measuring aneurysm size and presence of recurrent endoleak in patients with prior coil embolization of type 2 endoleaks. MATERIALS AND METHODS A total of 65 CTAs were retrospectively reviewed in a cohort of 27 patients (25 men; two women; mean age, 77.4 years) who had prior endoleak embolization after EVAR. Endoleak embolizations included transarterial ( n = 8) and translumbar ( n = 19) approaches. In each patient, maximal aneurysm diameter and presence/absence of recurrent endoleak was measured independently by two observers. Cohen's Kappa statistic was used to assess interobserver agreement, as well as paired two-tailed Student t tests for aneurysm diameter. RESULTS Recurrent type 2 endoleaks were detected with CTA in eight of 27 patients (30%) and on 13 of 65 CTAs (20%). A high degree of correlation (98.5%) was also seen between the two observers for presence of endoleak (Kappa 0.95). Mean aneurysm diameter for the entire cohort correlated closely between both observers: 54.8 mm ± 1.1 for observer A and 54.9 mm ± 1.1 for observer B ( P = .66). There was a disagreement between the readers of greater than 2 mm regarding aneurysm size in 13.8% of the CTAs (nine of 65 CTAs). CONCLUSION Despite the presence of streak artifact on CTA following coil embolization of type 2 endoleaks, CTA remains a useful study for following patients. The presence of embolization coils does not prevent CTA measurement of aneurysm diameter and detection of recurrent endoleak with a high degree of interobserver agreement.

Translumbar embolization was used to treat 11 type 2 endoleaks in nine patients with the liquid embolic agent n-butyl cyanoacrylate (NBCA). Nine of the embolizations were performed with a combination of stainless-steel coils and NBCAJ and the other two were performed with NBCA alone. There was complete occlusion on initial computed tomographic (CT) angiography in six of nine patients (66%), including the two cases treated with NBCA alone. Persistent endoleak on initial CT angiography occurred in three of nine patients (33%). Two of these patients underwent successful repeated embolization with NBCA. Aneurysm size remained unchanged in four patients (44%), decreased in four patients (44%), and increased in one patient (11%). No complications occurred. Initial results with the use of NBCA for endoleak embolization are encouraging.

PURPOSE Accurate endoleak detection and classification is critical for the follow-up of patients who have undergone endovascular aneurysm repair (EVAR). This determination is often made with computed tomography angiography (CTA). This investigation was performed to determine the accuracy of CTA in the classification of endoleaks in patients who have undergone EVAR. MATERIALS AND METHODS Thirty-six patients with endoleaks underwent both CTA and conventional contrast digital subtraction angiography (DSA) to determine endoleak etiology. Two independent radiologists determined the source of the endoleak based on a retrospective review of the CTA. The results of the CTA-based endoleak classification were compared to the reference standard, contrast DSA. RESULTS There was agreement regarding endoleak classification between CTA and DSA on 86% of the patients (31 of 36 patients). Correlation between the CTA reading of the two readers was 94% (34 of 36 patients), yielding a kappa statistic of 0.8. In three patients, the CTA reading incorrectly classified endoleaks as type 2 when the endoleaks were actually type 1 endoleaks on DSA. One patient was incorrectly classified as having a type 1 endoleak on CTA when it was a type 2 endoleak on DSA. Finally, one patient had a type 1 endoleak on DSA that was incorrectly classified as a type 3 endoleak on CTA. The change in CTA endoleak classification based on the DSA resulted in a significant change in patient management in four of the 36 patients (11%). CONCLUSIONS Endoleak classification based on CTA correlates fairly well with DSA findings. However, optimal endoleak management requires performance of selective angiograms with DSA to classify endoleaks that are detected on CTA.

When embolization of a collateral (type II) endoleak after endovascular repair of an abdominal aortic aneurysm is indicated, endoleak embolization with a translumbar approach is often the procedure of choice. Because of the position of the endoleak, it is sometimes necessary to use a right-sided translumbar approach and traverse the inferior vena cava when accessing the endoleak. Twelve type II endoleaks in nine patients were treated with transcaval translumbar embolization during a 34-month period. No clinically significant hemorrhage occurred. Embolizing type II endoleaks with a right translumbar approach is feasible. Long-term follow-up with more patients is necessary to fully evaluate the durability of this procedure.

Endovascular repair of abdominal aortic aneurysms shows promising initial results. Endoleaks represent one of the unique causes of endovascular repair failure not seen with traditional abdominal aortic aneurysm repair. Endoleaks occur when there is blood flow outside the stent-graft lumen but within the aneurysm sac. They can be difficult to diagnose and treat, and their management is a source of continued controversy. This review further defines endoleaks and the clinical challenges that they create. Current methods for endoleak detection, classification, and management are reviewed.

Six patients, ranging from 69 to 81 years of age, underwent iliac artery embolization with use of Detachable Silicon Balloons (DSB) 11-14 days before stent-graft repair of aneurysms. Balloons of 8.8-mm, 9.4-mm, and 9.9-mm sizes were used with 20-30 g of release force. Deployment difficulty was experienced in three cases. Five of six cases were successful, with the iliac artery remaining occluded at the time of endografting; one case required subsequent coil replacement. The average operative time for balloon embolization (75 min +/- 28) was shorter than that in 18 cases of coil embolization performed within the same time period (111 min +/- 105), but the difference was not significant (P = .21). Postoperatively, one patient (17%) reported buttock claudication after the procedure. Use of the DSB represents an alternative to use of coils for embolization of large and tortuous iliac arteries.

ENDOVASCULAR repair of abdominal aortic aneurysms is a rapidly proliferating technique. Unlike conventional “open” aneurysm repairs, patients may develop immediate or delayed “endoleaks” requiring remediation either by catheter-based or surgical intervention. Endoleaks are classified into one of four categories (1,2). A leak at an attachment site (proximal, middle, or distal) is classified as type 1. In collateral endoleaks (type 2), blood travels from a branch vessel in the nonstented portion of the aorta or iliac arteries. Blood flow then takes a circuitous route, emptying into the aneurysm sac via retrograde flow through a lumbar artery, inferior mesenteric artery, or other vessel originating from the aneurysm. This type of leak is the most common and is unrelated to the type or configuration of stent-graft used. Endoleaks that are a result of a defect in, or failure of, the graft material are defined as type 3, whereas those resulting from stent-graft wall porosity are called type 4. Most controversial is the fate of branch vessel (type 2) endoleaks, usually arising from inferior mesenteric artery or lumbar artery retrograde flow into the excluded abdominal aortic aneurysm sac. While some of these leaks have been demonstrated to thrombose with the passage of time, distressing reports of continued abdominal aortic aneurysm enlargement from untreated branch endoleaks are accumulating (3–5). One of the barriers to catheterbased remediation of type 2 endoleaks has been access to the offending vessel supplying the excluded abdominal aortic aneurysm sac. Access to the inferior mesenteric artery can be gained by catheterization of the superior mesenteric artery and selecting the inferior mesenteric artery through collaterals. This approach is tedious, time-consuming, and not always successful, particularly if there is an incomplete arc connecting the SMA-IMA axis (6– 10). Patent lumbar arteries are even less easily accessed. Translumbar access to the abdominal aorta was first introduced more than 70 years ago (11,12). Modifications made this technique of clinical value in the 1960s (13). Even though the long history and safety of this procedure is well documented, at the present time, translumbar angiography is usually reserved for patients with poor peripheral vascular access. The purpose of our investigation was to access the feasibility of direct aneurysm sac puncture and endoleak embolization via a translumbar approach. MATERIALS AND METHODS

PURPOSE The occurrence of kinking of stent-graft limbs depends on the patient's anatomy and the device used. The purpose of this investigation was to determine the rates of limb kinking in supported and unsupported aortic stent-grafts. MATERIALS AND METHODS The authors performed a retrospective review of patients undergoing placement of either a Guidant Ancure/EGS or Medtronic Talent aortic stent-graft for the treatment of abdominal aortic aneurysm as part of separate phase II and phase III clinical trials. The records of 91 consecutive patients with 149 limbs were reviewed. The type and configuration of each device and any procedure performed specifically relating to limb patency was recorded. An analysis was then performed comparing the rates of kinking in supported and unsupported groups. A review of the literature was also performed. RESULTS Overall, there was kinking in 18 of 149 limbs (12%). In the supported stent-graft group, 48 bifurcated and 26 aortomonoiliac grafts were placed, with a total of 122 limbs at risk. Six limbs (5%) in five patients required intervention as a result of limb kinking. Stents were placed intraoperatively in two limbs (2%) and postoperatively in four limbs (3%) for thrombosis or severe stenosis. In the unsupported group, 12 bifurcated and three aortomonoiliac grafts were placed, with a total of 27 limbs at risk. Twelve limbs (44%) in eight patients required some type of intervention as a result of limb kinking. Stents were placed intraoperatively in seven limbs (26%) and postoperatively in five limbs (19%) for thrombosis or severe stenosis. Rates of limb kinking were significantly different between the supported and unsupported groups ( P CONCLUSIONS The use of supported versus unsupported stentgrafts impacts the occurrence of limb kinking. A direct comparison of the groups suggests that an unsupported stent-graft will be more than 15 times more likely than a supported system to require intervention because of kinking.