Risk Factor Analysis for Buttock Claudication after Internal Iliac Artery Embolization with Endovascular Aortic Aneurysm Repair

Sandwich stent located in the iliac artery dislodged into the thoracic aorta and its remedy

The sandwich stent technique is a commonly used method to preserve unilateral internal iliac artery flow when treating iliac artery aneurysm. In this case, covered stent grafts (Viabahn, Gore) were used to build the iliac limb of a sandwich stent. However, if Viabahn is released without long sheath protection, the trigger wire is easily wound on another stent, resulting in the Viabahn delivery system being inseparable from the stent. If we drag it forcefully, it would easily cause the entire sandwich stent graft to shift or even fall into the thoracic aorta. This complication is catastrophic. Here we report the case of a patient whose sandwich stent system disengaged and entered the thoracic aorta. We took corresponding measures to remedy it.

Effect of preservation of antegrade hypogastric flow on development of claudication following aortoiliac aneurysm repair

OBJECTIVE

The objective of this study was to compare the rate of development of buttock claudication in patients undergoing aortoiliac aneurysm repair with and without exclusion of antegrade hypogastric arterial flow. In the absence of convincing data, questions remain regarding the best management of hypogastric arterial flow to prevent the theoretical risk of buttock claudication.

METHODS

The Veterans' Affairs Open Versus Endovascular Repair (OVER) Cooperative Study prospectively collected information on buttock claudication. Trial participants were specifically prompted both pre- and postoperatively to report the development of claudication symptoms at several anatomic levels. Of note, trial investigators were specifically trained to occlude the trunk hypogastric arterial, preserving the anterior and posterior divisions. Bayesian survival models were created to evaluate time to development of left, right, or bilateral buttock claudication according to the presence/absence of antegrade hypogastric perfusion.

RESULTS

A total of 881 patients from the OVER trial with information regarding status of hypogastric flow were included in the analysis. Of these, 788 patients maintained bilateral antegrade hypogastric arterial perfusion, 63 had right hypogastric coverage/occlusion, and 27 had left hypogastric coverage/occlusion, whereas 3 patients had bilateral hypogastric coverage/occlusion. Just under 5% of all patients (n = 41) developed buttock claudication. After adjustment for smoking, chronic obstructive pulmonary disease, medications, study arm, preoperative activity level, body mass index, age, and diabetes, intervention-related changes to hypogastric perfusion had no effect on time to development of buttock claudication. A Maximum A Posteriori Kullback- Leibler misfit χ² was 14.45 with 24 degrees of freedom, resulting in a goodness of fit P-value of P = .94, indicative of a good fit.

CONCLUSIONS

OVER is the largest aneurysm treatment study to prospectively collect data related to the development of claudication as well as hypogastric preservation status. Despite this, we were unable to find evidence to support the assertion that preservation of antegrade hypogastric flow decreases the rate of development of buttock claudication symptoms. The low rate of development of buttock claudication overall and in the subgroups is striking.

Effects of nonselective internal iliac artery angioembolization on pelvic venous flow in the swine model

BACKGROUND

Pelvic angioembolization (AE) is a mainstay in the treatment algorithm for pelvic hemorrhage from pelvic fractures. Nonselective AE refers to embolization of the bilateral internal iliac arteries (IIAs) proximally rather than embolization of their tributaries distally. The aim of this study was to quantify the effect of nonselective pelvic AE on pelvic venous flow in a swine model. We hypothesized that internal iliac vein (IIV) flow following IIA AE is reduced by half.

METHODS

Nine Yorkshire swine underwent nonselective right IIA gelfoam AE, followed by left. Pelvic arterial and venous diameter, velocity, and flow were recorded at baseline, after right IIA AE and after left IIA AE. Linear mixed-effect model and signed rank test were used to evaluate significant changes between the three time points.

RESULTS

Eight swine (77.8 ± 7.1 kg) underwent successful nonselective IIA AE based on achieving arterial resistive index of 1.0. One case was aborted because of technical difficulties. Compared with baseline, right IIV flow rate dropped by 36% ± 29% (p < 0.05) and 54% ± 29% (p < 0.01) following right and left IIA AE, respectively. Right IIA AE had no initial effect on left IIV flow (0.37% ± 99%, p = 0.95). However, after left IIA AE, left IIV flow reduced by 54% ± 27% (p < 0.01). Internal iliac artery AE had no effect on the external iliac arterial or venous flow rates and no effect on inferior vena cava flow rate.

CONCLUSION

The effect of unilateral and bilateral IIA AE on IIV flow appears to be additive. Despite bilateral IIA AE, pelvic venous flow is diminished but not absent. There is abundant collateral circulation between the external and internal iliac vascular systems. Arterial embolization may reduce venous flow and improve on resuscitation efforts in those with unstable pelvic fractures.

LEVEL OF EVIDENCE

Prognostic, level IV.

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 blood flow distribution after hypogastric artery embolization and the ischaemic tolerance of the pelvic circulation

This study aimed to compare the pelvic cavity vasculature before and after the interventional occlusion of a hypogastric artery (IOHA) and to reveal the protective mechanism of the collateral vessels against pelvic ischaemia.Sixty-nine patients with abdominal aortic or aortoiliac aneurysms who underwent endovascular aneurysm repair accompanied with IOHA were retrospectively analysed. Patients were divided into those who complained of buttock claudication (BC) group and asymptomatic patients (non-BC group).Two analyses were performed. In Study 1, the factors associated with postoperative BC were evaluated in patients who underwent IOHA using only 0.035 Tornade embolization coils. In Study 2, the pelvic arterial volume (PAV) was assessed in patients with both pre- and postoperative multidetector computed tomography images. PAV was calculated by subtracting the aortoiliac artery volume from the total PAV. The PAV ratio was defined as the postoperative PAV divided by preoperative PAV and represented collateral development in the pelvis.In Study 1, BC occurred in 16 patients (BC group) and did not occur in 25 patients (non-BC group). Significantly more coils were used in the BC group than in the non-BC group (8.6 ± 1.0 vs 5.6 ± 0.83, P = .013). Study 2 had 24 patients in the BC group and 31 patients in the non-BC group. The PAV ratio was significantly higher in the BC group than in the non-BC group (0.93 ± 0.05 vs 0.62 ± 0.04, P<.0001).The use of more coils in IOHA is associated with BC. In addition, volumetric analysis revealed that less collateral vessel development occurred in the non-BC group than in the BC group, which might reflect a potential reservation capacity of non-BC patients for acute pelvic ischaemia.

Open Versus Endovascular Repair of Isolated Iliac Artery Aneurysms

PURPOSE:

Outcomes of open iliac artery repair (OIR) and endovascular iliac artery repair (EVIR) were compared at a tertiary referral vascular center.

METHODS:

From 2004 to 2015, all patients treated for isolated iliac artery aneurysms (IAAs) were retrospectively identified, and patient records and computed tomography (CT) scans were analyzed. The primary end point was overall survival; secondary end points were 30-day mortality and morbidity and freedom from reintervention. For follow-up, data from outpatient visits and CT scans following a standard surveillance protocol were used.

RESULTS:

A total of 106 IAAs in 94 patients were treated (mean follow-up: 35.7 months; 66 OIR; 40 EVIR). Six (15%) aneurysms from the EVIR group and 4 (6.1%) from open-operated IAA presented in the state of rupture. There was no difference in overall survival between EVIR and OIR ( P = .14). In multivariable analysis, higher risk of death was associated with ruptured IAA (rIAA; hazard ratio [HR]: 40.44, 95% confidence interval [CI]: 2.05-796.18; P = .02) and coronary heart disease (HR: 11.07, 95% CI: 1.94-63.36; P < .01). The 30-day mortality was 1.9% overall (0% OIR, 5.0% EVIR, P = .27), but there were no differences between OIR and EVIR in 30-day morbidity ( P = .11). Freedom from reintervention was higher for OIR than for EVIR ( P < .01). In multivariable analysis, a higher reintervention rate was seen in EVIR (HR: 10.80, 95% CI: 2.20-53.01; P < .01) and in rIAA (HR: 12.02, 95% CI: 1.31-111.11; P = .03).

CONCLUSION:

Iliac artery aneurysmss can be safely and effectively treated by EVIR or OIR regarding 30-day morbidity, mortality, and long-term survival, although freedom from reintervention is significantly lower after EVIR.

Persistent Buttock Claudication after Endovascular Abdominal Aortic Aneurysm Repair

We describe the successful surgical treatment of a 71-year-old man affected by right buttock claudication after a right internal iliac artery (IIA) coil embolization as an adjunct to endovascular iliac artery aneurysm repair. Computed tomography angiography revealed extensive aortoiliac calcifications and thrombus in the vessel walls. Despite patency of the contralateral IIA and preservation of right distal collateral flow through ipsilateral hypogastric branches, the symptom was persistent and disabling. The high-risk patient underwent an "open" repair of the infrarenal abdominal aneurysm with removal of the entire stent-graft and concomitant revascularization of the right IIA. Post-operative recovery was uneventful, and the patient remained asymptomatic during a 30-month follow-up. This case underscores the importance of considering all potential solutions, including open surgery, to preserve pelvic inflow after aortoiliac stent grafting, particularly for high-risk patients with vulnerable plaque and higher risk of thrombus embolization.

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.