Iliac anatomy and the incidence of adjunctive maneuvers during endovascular abdominal aortic aneurysm repair

Impact of iliac access in elective and non-elective endovascular repair of abdominal aortic aneurysm

Endovascular aortic repair (EVAR) is nowadays the establishment treatment for patients with abdominal aortic aneurysm (AAA) both in elective and urgent setting. Despite the large applicability and satisfactory results, the presence of hostile iliac anatomy affects both technical and clinical success. This narrative review aimed to report the impact of iliac access and related adjunctive procedures in patients undergoing EVAR in elective and non-elective setting. Hostile iliac access can be defined in presence of narrowed, tortuous, calcified, or occluded iliac arteries. These iliac characteristics can be graded by the anatomic severity grade score to quantitatively assess anatomic complexity before undergoing treatment. Literature shows that iliac hostility has an impact on device navigability, insertion and perioperative and postoperative results. Overall, it has been correlated to higher rate of access issues, representing up to 30% of the first published EVAR experience. Recent innovations with low-profile endografts have reduced large-bore sheaths related issues. However, iliac-related complications still represent an issue, and several adjunctive endovascular and surgical strategies are nowadays available to overcome these complications during EVAR. In urgent settings iliac hostility can significantly impact on particular time sensitive procedures. Moreover, in case of severe hostility patients might be written off for EVAR repair might be inapplicable, exposing to higher mortality/morbidity risk in this urgent/emergent setting. In conclusion, an accurate anatomical evaluation of iliac arteries during preoperative planning, materials availability, and skilled preparation to face iliac-related issues are crucial to address these challenges.

Endovascular management of aortic aneurysm with severe neck angulation and/or iliac artery tortuosity using multiple stiff wire technique: a case series

Background

Suitable aortic neck is one of the essential components for thoracic endovascular aortic repair (TEVAR) and endovascular aortic repair (EVAR). Advanced techniques were developed to adjust and compromise the aneurysm neck angulation but with adding additional devices and complexity to the procedure. We proposed a simple technique to modify severe neck angulation and/or iliac artery tortuosity by using the multiple stiff wire (MSW) technique.

Method

Two femoral accesses were required for the MSW technique. A guidewire with a support catheter was inserted through the right and left femoral arteries and positioned in the abdominal or thoracic aorta. Wire exchanges were done with extra stiff wire in both femoral accesses. It can be considered to add multiple stiff wires to align the torturous neck / iliac artery. Delivery of the stent graft main body can be done via one of the accesses.

Result

Six patients with different aortic pathology were admitted to our hospital. Four patients undergo EVAR procedure and two patients undergo TEVAR procedure. All patients had aortic neck angulation problems with one patient having iliac artery tortuosity. MSW technique was performed on the patients with good results. Follow-up CTA after 3 months revealed a good stent position without stent migration and no endoleak was found in all but one patient.

Conclusion

MSW technique is a simple and effective technique to modify aortic neck/iliac artery angulation in TEVAR or EVAR procedure.

Clinical Outcomes of Internal Iliac Artery Interruption during Endovascular Aneurysm Repair

Purpose

This study aimed to investigate the clinical outcomes of internal iliac artery (IIA) interruption during endovascular aneurysm repair (EVAR) and to identify the risk factors for ischemic complications.

Materials and Methods

Endovascular treatment was performed in 316 patients with aneurysms or pseudoaneurysms of the abdominal aorta or iliac arteries between March 2006 and January 2022. Medical records and radiological imaging studies were retrospectively reviewed. The incidences of buttock claudication, ischemic colitis, and spinal cord ischemia after IIA interruption were investigated as clinical outcomes. Binary logistic regression analysis were performed to identify the risk factors.

Results

IIA embolization was performed in 78 patients. Among the 42 patients who underwent IIA flow preservation procedures, the one-month computed tomography detected early failure in five patients. The origin of the IIA was covered with an endograft in ten patients who did not undergo embolization. Eventually, interruption of the IIA by EVAR was observed in 93 patients. Considering preoperative IIA occlusion, there was a total of six patients who did not have at least one IIA patency. Buttock claudication occurred in 32.6% of the patients, and none of the patients had ischemic colitis or spinal cord ischemia. In multivariable analysis, age ≤80 years and isolated iliac artery aneurysm were associated with the development of postoperative buttock claudication.

Conclusion

The most common complication after IIA interruption is buttock claudication; however, critical complications such as ischemic colitis or spinal cord ischemia are rare, even in bilateral IIA occlusion. Adjunctive procedures to preserve bilateral IIA perfusion should be adopted selectively.

Risk Factors for Early and Late Iliac Limb Occlusions of Stent Grafts Extending to the External Iliac Artery after Endovascular Abdominal Aneurysm Repair

BACKGROUND

Iliac limb stent grafting to the external iliac artery (EIA) is a commonly performed procedure in various situation during endovascular abdominal aneurysm repair (EVAR). However, this procedure is associated with a risk of graft occlusion. We evaluated risk factors affecting occlusion among patients who underwent iliac limb stent-graft extension to the EIA.

MATERIALS AND METHODS

We compared occluded limbs with patent limbs during the follow-up period using variables, including anatomical values, demographics, and other factors. Thereafter, we divided the occluded limbs into early and late occlusion subgroups. The main and subgroup analyses used the same variables. Survival analysis was performed to evaluate time-dependent risk factors for late limb occlusion.

RESULTS

From 2007 to 2016, 766 iliac limbs from 383 patients who underwent EVAR were initially included in our analysis. Among them, 134 iliac limbs underwent limb extension to the EIA. The limb extension was a significant risk factor for occlusion (hazard ratio = 6.34, P < 0.001). Occlusion occurred in 10 patients who underwent iliac limb extension. The size of common iliac artery (CIA) was associated with occlusion. The most significant factor was iliac bifurcation diameter (patent vs. occluded limbs, 21.6 ± 7.6 vs. 27.5 ± 9.5 mm, P = 0.005). Subgroup analysis revealed that the CIAs of the early occlusion subgroup were generally more tortuous (1.16 ± 0.33 vs. 1.47 ± 0.25, P = 0.091) and longer (53 ± 24 vs. 74 ± 9, P = 0.01) than those of the patent limb group. In addition, the EIA diameters of the late occlusion subgroup were narrower than those of the patent limb group (10.9 ± 1.6 mm vs. 9.1 ± 0.8 mm, P = 0.011). Using the log-rank test, those patients with an EIA diameter narrower than 10.1 mm had a higher risk for late limb occlusion (log-rank χ² = 5.73, P = 0.017) and the patients who did not take at least a single antiplatelet agent had a significantly higher chance of limb occlusion (log-rank χ² = 11.029, P = 0.001). In addition, the patients who did not take a statin had a higher risk for late limb occlusion (log-rank χ² = 7.41, P = 0.007).

CONCLUSIONS

Among patients who underwent EVAR with iliac limb extension, the CIA length affected early limb occlusion and predisposed patients to vessel injury or stent-graft kinking, and there was the possibility that CIA tortuosity was associated with a higher risk. The late occlusion subgroup had narrower EIAs than the patent limb group. Appropriate antiplatelet and statin therapy is expected to play a key role in the prevention of late limb occlusion after EVAR.

Adjunctive Procedures for Challenging Endovascular Abdominal Aortic Repair: When Needed and How Effective?

Endovascular aneurysm repair (EVAR) is now considered the first choice treatment modality for abdominal aortic aneurysm (AAA) treatment. Advocates for endovascular strategies will try to treat all AAA by EVAR, regardless if the anatomy is conducive for treatment or not. However, the long-term outcomes of EVAR outside the instructions for use (IFU) due to a hostile aneurysmal neck or iliac artery anatomy are known to be poor. The EVAR procedures can be classified according to the technical difficulty, IFU, and need for visceral revascularization: standard, adjunctive, and complex EVAR. The situation required for adjunctive procedures can be classified as the following four steps: a hostile neck (i.e., short or severely angled); large inferior mesenteric or lumbar artery; tough iliac artery anatomy, such as a short common iliac artery and stenotic external iliac artery; and limitations in vascular access. This article will discuss the adjunctive procedures to overcome hostile aneurysm neck and unsuitable iliac artery anatomy.

Changes in Apposition of Endograft Limbs in the Iliac Arteries After Endovascular Aneurysm Repair: Determination With New Computed Tomography-Applied Software

Purpose: To validate new computed tomography (CT)-applied software used to determine endograft limb position and apposition after endovascular aneurysm repair (EVAR). Materials and Methods: Twelve EVAR patients (mean age 81±6 years; 10 men) with distal stent-graft extensions for 15 (3 bilateral) type Ib endoleaks during follow-up were selected based on the availability of the following CT studies: pre-EVAR, 1 month, and the penultimate scan prior to the scan disclosing the type Ib endoleak. Twelve patients (mean age 82±7 years; 11 men) without endoleak and a similar interval between the primary EVAR procedure and the penultimate CT scan of the endoleak group were selected as controls using measurements from both endograft limbs (n=21, 3 excluded). Prototype Vascular Imaging Analysis software was adapted to calculate 6 parameters for the distal apposition zone: fabric distance, shortest apposition length, endograft diameter, iliac seal surface (ISS), iliac endograft apposition surface (IEAS), and percentage of iliac surface coverage (IEAS/ISS × 100). Measurements were performed on the preoperative, first postoperative, and penultimate/matched follow-up CT scans. Interobserver variability was assessed with the intraclass correlation coefficient (ICC). Continuous data are presented as the median [interquartile range (IQR) Q1, Q3]. Results: CTA follow-up was not significantly different between the endoleak and control groups [30 months (IQR 18, 58) vs 36 months (IQR 21, 59), p=0.843]. Interobserver agreement was good to excellent for all parameters (ICC 0.879-0.985). Preoperative anatomy and endograft dimensions on the first follow-up CTA scan did not differ significantly between the groups. When the penultimate CTA scan was compared with the first postoperative CT scan, endograft dimensions had significantly changed in the endoleak group; importantly, apposition was significantly decreased, and fabric distance was significantly increased, indicating limb retraction. Differences in changes in endograft dimensions were significant between the groups. Conclusion: New CT-applied software was introduced to visualize apposition and position changes of endograft limbs during follow-up. The software demonstrated good-to-excellent interobserver agreement and enabled accurate analysis of post-EVAR endograft dimensions. Significant changes in apposition and position were observed with the software on the penultimate CT scan prior to diagnosis of type Ib endoleak.

Treatment options for isolated iliac artery aneurysms and their impact on aortic diameter after treatment

Purpose

Isolated iliac artery aneurysm (IIAA) is uncommon. It is frequently treated by endovascular aneurysm repair (EVAR). This study was to evaluate treatment results of IIAA and survey aortic diameter after EVAR.

Methods

Patients treated for IIAA in Seoul St. Mary's Hospital and Bundang Seoul National University from 2005 to April 2016 were retrospectively enrolled. The inclusion criteria of IIAA was >30 mm of iliac artery aneurysm without abdominal aortic aneurysm, which was treated by open surgical repair (OSR) or EVAR. Patients' clinical characteristics, treatment results, and mortality were obtained from electronic medical records. Diameters of aorta and iliac arteries were measured periodically with scheduled interval based on CT scans.

Results

Forty-nine patients (40 males; mean age, 71.9 ± 11.1 years) were enrolled. Five ruptured IIAAs were treated with EVAR (n = 1) or hybrid methods (n = 4). The diameter of ruptured IIAAs was 65 ± 31.4 mm, which was not significantly different from that of elective (44.3 ± 17.0 mm). Forty-four elective IIAA underwent 9 OSR, 31 EVARs, and 3 hybrid treatments (15 bifurcated and 12 straight stent-grafts). Treatment success rate was 93.8% without hospital mortality. There were 4 type I endoleak, 1 type II endoleak, and 1 type III endoleak without aneurysm-related mortality during follow-up. However, the aortic diameter was increased over time though there was no change or decrease in common iliac artery's diameter.

Conclusion

Treatment of IIAA included various endovascular modalities as well as open surgery. Regular surveillance is still needed due to aortic dilatation after its treatment.

Early Experiences of Sandwich Technique to Preserve Pelvic Circulation during Endovascular Aneurysm Repair

Purpose

To report experiences of the sandwich technique (ST) for preservation of pelvic flow during endovascular repair of complex aortic or aortoiliac aneurysms.

Materials and Methods

Eight patients underwent elective endovascular aneurysm repair (EVAR) using the ST between March 2013 and February 2017. The anatomic indications for the ST were complex aortoiliac aneurysms (5 cases), abdominal aortic aneurysms (AAA) with non-diseased short common iliac arteries (2 cases) and AAA with unilateral occluded iliac artery (1 case). The ST was performed through both femoral and brachial approach. Patient clinical and radiologic data were collected and analyzed.

Results

Eight patients (7 male; mean age, 73.4 years) were followed over a mean period of 277 days (range, 9–1,106 days). The technical success rate was 100%. The primary patency rate of the iliac stent-grafts was 88% (14/16 cases). One internal iliac and 1 external iliac stent-graft occlusion was observed during the early postoperative period. There was 1 gutter endoleak which disappeared spontaneously within 4 days, and there were 2 type II endoleaks: one treated by coil embolization after 13 months, and the other observed without treatment. There were no cases of sac growth or aneurysm-related deaths, and no cases of buttock claudication or impotence.

Conclusion

The ST is a safe and feasible technique to preserve pelvic circulation during endovascular treatment of complex aortoiliac aneurysms. The need to expand the indications for complex EVARs with adjunctive procedures, such as the ST is highlighted in situations where branched/fenestrated device availability is limited.

Access From Above-Bailout Solution for Intraoperative Distal Migration of Abdominal Aortic Stent Graft

The majority of the ruptured abdominal aortic aneurysms today is treated endovascularly. In cases with short aneurysm neck, chimney technique can be used to extend landing zone in emergency setting. Additionally, the repositioning ability of C3 delivery system (Gore & Associates) allows better positioning in cases with challenging anatomy. In our experience, proximal reposition of partially deployed device can be problematic in some patients. We present a case of endovascular repair of ruptured abdominal aortic aneurysm using chimney technique where proximal reposition was achieved by snaring the aortic device via axillary access.

Early and Late Endograft Limb Proximal Migration with Resulting Type 1b Endoleak following an EVAR for Ruptured AAA

Introduction. Seal zone failure after EVAR leads to type 1 endoleaks and increases the risk of delayed aortic rupture. Type 1b endoleaks, although rare, represent a true risk to the repair. Case Presentation. We report the case of a 65-year-old female who underwent emergent endovascular repair for a ruptured infrarenal abdominal aortic aneurysm and developed bilateral type 1b endoleaks following proximal migration of both endograft limbs. The right-side failure was diagnosed within 48 hours from the initial repair and the left side at the 1-year follow-up. Both sides were successfully treated with endovascular techniques. A review of the literature with an analysis of potential risk factors is also reported. Conclusion. For patients undergoing EVAR for ruptured AAA and with noncalcified iliac arteries, more aggressive oversizing of the iliac limbs is recommended to prevents distal seal zone failures.

Influence of Anatomic Angulations in Chimney and Fenestrated Endovascular Aneurysm Repair

BACKGROUND

The lack of widespread availability of Fenestrated endovascular aneurysm repair (F-EVAR) encouraged alternative strategies. Hence, Chimney graft (CG)-EVAR spread when costs, manufacturing delays, or anatomy preclude F-EVAR. Our objective is to evaluate CG- and F-EVAR outcomes depending on the angulation of target renal arteries and hostility of iliac accesses in order to determine the potential impact of a choice made between both techniques on the basis of preoperative anatomic criteria.

METHODS

Consecutive patients treated by CG-EVAR or F-EVAR, from January 2010 to January 2015, were considered for inclusion. Anatomic parameters were defined by preoperative computed tomography angiography. A subgroup analysis was performed depending on renal arteries' angulation (cut-off: -30°) and iliac arteries' hostility (cut-off: diameter <6 mm, tortuosity index = 3).

RESULTS

Twenty-six patients were included the CG group (mean age 74.7 ± 6.9 years, 30 target vessels) and 66 in the F-EVAR group (71.7 ± 7.9 years, 133 target vessels). Infrarenal aortic neck length was significantly longer for CG-EVAR (3.3 ± 3.7 vs. 1.8 ± 3.2 mm, P = 0.04), while the distance between the superior mesenteric artery and highest renal artery was shorter in the CG group (11.7 ± 6.2 mm vs. 14.1 ± 5.9 mm, P = 0.06). Longitudinal angulation of the right renal artery was not statistically different between both groups, while the left renal artery presented with a significantly more downward angulation in the CG group (-32.0 ± 15.3 vs. -19.0 ± 19.6, P = 0.003). There were significantly more grade 3 iliac tortuosity indexes for CG-EVAR (P = 0.03) with significantly smaller external iliac diameters (7.8 ± 1.7 vs. 8.8 ± 1.6 mm, P = 0.0009). There was 1 renal artery early occlusion in the <-30° CG subgroup and 2 in the <-30° F-EVAR subgroup where severe downward angulation crushed the stents, with a tendency toward higher early occlusions compared with the ≥-30° F-EVAR subgroup (P = 0.054). Mean follow-up duration was 20 months in the CG group and 14 in the F-EVAR group. Kaplan-Meier estimates showed no significant difference in terms of overall survival, freedom from reintervention, freedom from type I or III endoleak, or patency. In the CG group, 14 patients (53.8%) presented with hostile iliac accesses without any significant difference in terms of limb events.

CONCLUSIONS

CG-EVAR is a complementary strategy to F-EVAR, and understanding which technique is applicable to which patient is important to improve outcomes. Our results suggest that considering renal artery angulation and diameter, iliac artery hostility, and aortic neck length among other parameters may help the surgeon make a decision toward the endovascular strategy that seems best suited for each specific patient.

An anatomic risk model to screen post endovascular aneurysm repair patients for aneurysm sac enlargement

BACKGROUND

Follow-up computed tomography angiography (CTA) scans add considerable postimplantation costs to endovascular aneurysm repairs (EVARs) of abdominal aortic aneurysms (AAAs). By building a risk model, we hope to identify patients at low risk for aneurysm sac enlargement to minimize unnecessary CTAs.

METHODS

895 consecutive patients who underwent EVAR for AAA were reviewed, of which 556 met inclusion criteria. A Probit model was created for aneurysm sac enlargement, with preoperative aneurysm morphology, patient demographics, and operative details as variables.

RESULTS

Our final model included 287 patients and had a sensitivity of 100%, a specificity of 68.9%, and an accuracy of 70.4%. Ninety-nine (35%) of patients were assigned to the high-risk group, whereas 188 (65%) of patients were assigned to the low-risk group. Notably, regarding anatomic variables, our model reported that age, pulmonary comorbidities, aortic neck diameter, iliac artery length, and aneurysms were independent predictors of post-EVAR sac enlargement. With the exception of age, all statistically significant variables were qualitatively supported by prior literature. With regards to secondary outcomes, the high-risk group had significantly higher proportions of AAA-related deaths (5.1% versus 1.1%, P = 0.037) and Type 1 endoleaks (9.1% versus 3.2%, P = 0.033).

CONCLUSIONS

Our model is a decent predictor of patients at low risk for post AAA EVAR aneurysm sac enlargement and associated complications. With additional validation and refinement, it could be applied to practices to cut down on the overall need for postimplantation CTA.

Internal Hernia Underneath an Elongated External Iliac Artery: A Complication After Extended Pelvic Lymphadenectomy and Robotic-assisted Laparoscopic Prostatectomy

Small bowel herniation underneath the iliac vessel after transperitoneal pelvic lymphadenectomy is a rare complication. This report describes the first case of bowel incarceration behind the external iliac artery after transperitoneal robotic-assisted radical prostatectomy with extended lymph node dissection in a patient with prostate cancer 1 year after surgery. After diagnosis on CT scan, an open resection of the ischemic bowel was performed. Because of thrombosis, the external iliac artery was opened, the clot was removed and the elongated artery was resected with end-to-end anastomosis. In case of a meandering iliac artery, a retroperitonealization after pelvic lymphadenectomy might be discussed.