Isolated iliac artery aneurysms: Endovascular versus open elective repair

Patients and methods 

From January 1998 to December 2005, we treated 55 patients with 58 SIAAs greater than 3 cm in diameter. Thirty-two patients with 33 SIAAs were treated by EVIAR, and 23 patients with 25 SIAAs underwent open surgical repair. All endovascular procedures were performed by a vascular surgeon (S.S.) in the Department of Vascular Surgery, Hospital “Porz am Rhein,” Cologne, Germany, and the open procedures were performed in the Department of Vascular Surgery, “G. Gennimatas” Hospital, Aristotle University of Thessaloniki, Greece.

Patients with infected iliac aneurysms and those with concurrent aortic aneurysmatic disease and diameter of the infrarenal aorta greater than 30 mm were excluded from the study. However, the EVIAR group included six patients with false SIAAs after a previous open bifurcated graft AAA repair. Table I shows the demographic data and the clinical presentation of the patients.

Table I. Clinical characteristics of patients treated with open or endovascular elective repair of isolated iliac artery aneurysms

	Variable	EVIAR, n = 32 (33 SSAAs)	Open repair, n = 23 (25 SSAAs)	P value
	Age (y)			.206
	Mean ± SD	64±7.6	67±7.2
	Range	52-87	54-81
	Male gender	30(94%)	22(96%)	.624
	CAD or CHF history	18(56.3%)	11(47.8%)	.366
	Hypertension	13(40.6%)	18(78.3%)	.006
	COPD	10(31.3%)	6(26.1%)	.457
	CRF	3(9.4%)	3(13%)	.495
	Previous abdominal aortic operation	11(34.4%)	7(30.4%)	.496
	Diameter (mm)
	Mean ± SD	44.5±15.5	43.5±7.9
	Range	29-110	33-72	.756
	Symptomatic	12(37.5%)	10(43.5%)	.432

EVIAR, Endovascular iliac aneurysm repair; CAD, coronary artery disease; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; CRF, chronic renal failure.

In both centers, the standard preoperative workup included for all patients with normal renal function a spiral contrast-enhanced computed tomography scan, which was used for the assessment of the aneurysm’s anatomic characteristics and for the appropriate measurements in the EVIAR group. In patients with chronic renal failure, the preoperative aneurysm’s assessment was based on magnetic resonance scan. In a few cases, digital or magnetic resonance angiography was used selectively to detect severe tortuosity or stenosis of the iliac axis. Endovascular procedures were performed in the operating theater with the patient under endotracheal general anesthesia. In all EVIAR cases, vascular access was achieved through a small femoral cut-down, and intraoperative angiograms with marker catheters were used to confirm the preoperative measurements (diameters and length) and the selection of the stent graft’s appropriate size and to facilitate the precise deployment of the prothesis. Under fluoroscopy, the stent-graft devices were advanced into the iliac axis up to the planned graft deployment site. The optimal apposition of the graft was secured with postdeployment stent-graft dilation by using balloon catheters. Table II shows the 6 different commercially available stent grafts that were used in the 33 EVIAR patients. Device selection criteria were the suitability of the specific aneurysm’s anatomy and especially the length and diameter of the proximal and distal necks.

Table II. Operative data of the 33 EVIAR and 23 open operations

	Variable	EVIAR⁎	Open	P value
	Talent (iliac limb; Medtronic Vascular, Santa Rosa, Calif)	12(+4)†
	Passager (Boston Scientific, Watertown, Mass)	10(+2)†
	Excluder (iliac limb; W.L. Gore & Associates, Flagstaff, Ariz)	6
	Viabahn (W.L. Gore & Associates, Flagstaff, Ariz)	2
	Wallgraft (Boston Scientific, Natick, Mass)	2
	Vanguard (iliac limb; Boston Scientific, Natick, Mass)	1
	Silver bifurcated Dacron graft (Intervascular, Cedex, France)		4
	Fluoropassiv Dacron 8-mm graft (Vascutec, Inchinnan, Scotland)		12
	Carboflo PTFE 8-mm graft (Impra; Bard, Tempe, Ariz)		5
	“Simple” ligation		2
	Operative time, min (mean ± SD)	85.6±13.2	143±35.2	<.001
	Blood loss, mL (mean ± SD)	<50‡	318.3±120.2	<.001
	Postoperative hospital stay, d (mean ± SD)	2.1±0.6	4.8±1	<.001
	Buttock claudication	4	0	.105
	Wound complications	2	5	.099
	Postimplant syndrome	4	3	.630
	Follow-up, mo (mean ± SD)	35.3±21.3	31.3±19.9	.489

Statistically significant differences (at the .05 level) between the two groups are bold. EVIAR, Endovascular iliac aneurysm repair.

⁎ In 13 cases, the patent ipsilateral internal iliac artery was coil-embolized. † In 4 cases treated with Talent and 2 with Passager a second consecutive stent-graft was used. ‡ The blood loss through sheaths and femoral cut-down in all EVIAR cases was less than 50 mL.

In five cases, two consecutive stent grafts were used to achieve safe sealing and complete aneurysm exclusion. In two cases, postdeployment intraoperative angiograms showed proximal endoleaks, and a Palmaz XL-Stent (Cordis, Miami, Fla) was used to achieve complete proximal sealing. In one case, two separate femoral cut-downs and stent grafts were used to exclude bilateral SIAA. Device selection criteria changed through the 8 years of the study because of the evolution that occurred in commercially available stent grafts. The current technique includes mainly the use of iliac limbs or iliac extensions with a scheduled neck oversizing between 10% and 20% for the common iliac artery and 10% for the external iliac artery.

In 13 cases, the internal iliac artery, its branches, or both were embolized by using stainless-steel Gianturco coils with adherent fibers of polyester material (VortX spiral coils; Boston Scientific, Natick, Mass), whereas in 2 cases the native ipsilateral hypogastric artery (HA) was chronically occluded as a result of atherosclerosis. In all these cases, the contralateral HA was patent. In the eight cases in which the HA was aneurysmal, exclusion was achieved by embolization of the distal HA’s branches and coverage of the HA origin with a stent graft that extended from the common to the external iliac artery. In the remaining patients without HA aneurysms, the HA’s origin was coil-embolized before stent-graft deployment (Fig 1). There was no need for a postoperative intensive care unit (ICU) stay in any of the EVIAR patients. In the open group, four patients (one with contralateral HA occlusion) were treated under general endotracheal anesthesia by using midline laparotomy, a transperitoneal approach, and bifurcated Dacron graft (DuPont, Wilmington, Del) placement. In one of these cases, an extra side graft was placed for the separate revascularization of the left HA (Fig 2).

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Fig 1. Endovascular treatment of an isolated right common iliac aneurysm. (1) Extension and sizing of the aneurysm (measurements from preoperative computed tomographic scan). (2) Coil embolization of the right hypogastric artery using 7-mm spiral coils (VortX; Boston Scientific, Natick, Mass). (3) Proximal type I endoleak after placement of the stent graft (Talent iliac extension 16 × 20 × 105 mm rotated and deployed as 20 mm proximally and 16 mm distally; Medtronic Vascular, Santa Rosa, Calif). (4) Result after proximal Palmaz XL-Stent (Cordis, Miami, Fla) placement without endoleak.

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Fig 2. Bilateral isolated iliac artery aneurysms: open transperitoneal repair. (a) Multiplanar reformation computed tomographic scan shows the bilateral iliac aneurysms and hypogastric artery’s involvement. (b) Schematic depiction of the trifurcated graft placement. (c and d) Intraoperative images of the anastomotic sites.

In the remaining 17 open cases, epidural anesthesia and a lower lateral abdominal incision with a retroperitoneal approach to the entire iliac axis was used. Iliac repair and restoration of flow to the iliac axis was achieved by end-to-end graft placement (Dacron 8 mm in 12 and expanded polytetrafluoroethylene 8 mm in 5 cases). Revascularization of the ipsilateral internal iliac artery was achieved in the 15 of these cases, whereas in 2 the HA was ligated through the opened aneurysmal sac with a continuous suture before the restoration of the flow to the external iliac artery.

Finally, in the remaining two cases of hypogastric SIAA, both the proximal and distal necks of the aneurysm were ligated in one case, and in the second case, with very limited flow of the distal HA’s branches because of atherosclerosis, only the proximal neck was ligated. The four patients undergoing a transperitoneal approach under general anesthesia stayed at the ICU the first postoperative day, whereas there was no need for ICU stay in any of the patients who were treated through a retroperitoneal approach with epidural anesthesia.

Follow-up at 3, 6, 12, 18, and 24 months and annually thereafter included physical examination and duplex ultrasonography for all patients. Spiral computed tomographic scan was performed at the 1st, 6th, and 12th postoperative months and annually thereafter for all EVIAR patients to detect any migration, kinking, or endoleaks of the graft and to evaluate for possible aneurysm sac shrinkage. The mean follow-up period was similar in both groups: 35.3 ± 21.3 months for the EVIAR group and 31.3 ± 19.9 months for the open group (P < .489).

Statistical analysis was performed with SPSS (SPSS Inc, Chicago, Ill). Continuous data were compared by using the Student t test and categorical variables with the Fisher exact test as appropriate. The 3-year primary patency rates and freedom of secondary interventions were estimated by using the Kaplan-Meier life-table analysis.

Results 

The immediate technical success and early patency rates for the EVIAR cases were 100%. The renal function was not affected (increase of serum creatinine levels >10% beyond the second postoperative day) in any of these patients, even in the three EVIAR cases with chronic renal failure. Early complications occurred in four patients who underwent HA distal branch embolization. In these four cases, colonoscopy at the third postoperative day showed mild colonic mucosal ischemic changes. These four patients received conservative treatment with parenteral nutrition and broad-spectrum antibiotics for 1 week.

Control colonoscopy at the first month showed complete resolution of the colonic mucosal ischemia. These four patients also experienced transient buttock claudication at a walking distance of 0 to 100 m, which resolved by 4 weeks. There was no evidence of mild or serious colonic or pelvic structure ischemia in any of the other EVIAR cases. Two local groin hematomas also occurred that did not require further treatment. There was no 30-day mortality.

The 1-year and mid-term (36 months) primary graft patency rates in the EVIAR group were 97% in both intervals (Fig 3). Late complications included graft thrombosis 7 months after the EVIAR procedure in one octogenarian patient with a large (73-mm) SIAA. Despite the graft thrombosis, the patient had moderate claudication at a 100-m walking distance, and considering his advanced age, he refused the proposed secondary intervention. Excluding this case, 9 (28%) of the EVIAR-treated SIAA patients remained stable, and 23 cases (72%) had a minimal decrease in aneurysm size (defined as <10% of the preoperative diameter). During the entire follow-up period, there was no evidence of endoleaks, and, excluding the case of the graft thrombosis, there was no evidence of kinking or stent-graft migration in any other EVIAR-treated patient.

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Fig 3. Thirty-six-month graft primary patency rates in patients undergoing endovascular (EVIAR) or open repair of isolated iliac artery aneurysms (Kaplan-Meier life-table analysis, no significant difference; P = .938).

As shown in Table II,the mean operative time of open cases was 143 ± 35.2 minutes, compared with 85.6 ± 13.2 minutes for the EVIAR cases. The blood loss during the open procedures was approximately 318.3 ± 120.2 mL, whereas in the EVIAR group the mean blood loss was less than 50 mL. During surgery, five patients undergoing open repair required transfusion of one unit of packed red blood cells, and after surgery these same patients required transfusion of a second unit of packed red blood cells. The mean hospital stay of the open group patients was at 4.8 ± 1 days, including 1 day in the ICU for the four patients who were treated with a transperitoneal approach under general anesthesia. In contrast, the mean hospital stay of the EVIAR patients was only 2.1 ± 0.6 days, and the difference between the two groups concerning these three perioperative parameters was significant (P < .001). Two femoral wound complications occurred in the open group which were treated conservatively, two retroperitoneal incisional hematomas developed that necessitated transfusion of one unit of red packed cells in each case, and in one case, delayed healing of a left retroperitoneal incision occurred that was due to subcutaneous staphylococcus infection. There was also no 30-day mortality for patients treated with the open technique.

The 1-year and mid-term (36 months) primary graft patency rates in the open group were 100% in both intervals (Fig 3). Additionally, no evidence of buttock claudication or colonic or pelvic ischemia was found in any open-treated patients. Concerning the early and late complications, statistical analysis revealed no significant differences between the two groups of patients.

Discussion 

In this study, we compared the initial outcomes and mid-term results of the two different treatment options that are currently available for the management of isolated iliac artery aneurysms. Twenty-three consecutive patients were treated by conventional open repair in one center, and during the same period 32 consecutive patients were treated with an endovascular approach in a second center. This work represents the two centers’ experience with this problem and includes the potential of bias in the results even though it compares two consecutive series of patients treated with a single technique in each group.

Additionally, although secondary SIAAs after previous aortoiliac replacement or endovascular intervention are not true aneurysms, we included six patients with false SIAAs, after previous conventional aortoiliac reconstruction, in the EVIAR group because from the technical point of view these lesions require an approach similar to the true SIAAs, regardless of the etiology.12, 16 The demographic and clinical characteristics of the patients, as well as the anatomy and morphology of the treated aneurysms in both series, were similar to those described in previous reports, and there were no significant differences between groups.2, 7, 8, 12

Both techniques were associated with excellent immediate technical success and very good short- and mid-term (3 years) graft patency rates. Additionally, even though half of the patients had a history of coronary artery disease or congestive heart failure and almost one third had pulmonary obstructive disease, no postoperative myocardial infarctions, pulmonary complications, or deaths were observed. However, patients who underwent EVIAR treatment had a clear short-term advantage compared with the patients of the open surgical repair group, with earlier ambulation and hospital discharge. The mean operative time and the blood loss were also significant in favor of the EVIAR group.

In most (83%) open repair patients, regional anesthesia was used, whereas in all EVIAR patients general endotracheal anesthesia was performed because it is considered less time consuming and keeps the patient completely immobilized during the graft deployment. However, this difference between the two groups in anesthetic technique did not seem to affect the outcomes of EVIAR. A possible explanation for this might be that the short operative time (<90 minutes), the minimized blood loss, and the absence of any hemodynamic manipulations (ie, aortic clamping) in the EVIAR patients resulted in minimal aggravation of the patient’s cardiorespiratory function despite the mechanical ventilation of the general anesthesia. Conversely, most of the open group patients underwent a retroperitoneal approach with regional (epidural) anesthesia, the mean operative time was kept approximately at 2 hours 30 minutes, and the mean blood loss remained low. These factors may also have resulted in fewer cardiorespiratory complications.

In contrast with previous reports12, 17, 18, 19, 20 by Boules et al12 and Sahgal et al20 of a significant decrease of SIAA diameters in 87% and 97% of patients, respectively, in our series significant shrinkage of the aneurysm’s sac (>10% of the preoperative diameter) was observed in only one patient. Additionally, in that case the sac shrinkage and thrombus organization of a large (73-mm) SIAA resulted in angulation of the two deployed consecutive stent grafts, and this compromised iliac flow and subsequently led to graft thrombosis. Furthermore, the distal landing zone in that case was in the external iliac artery, and mirroring the data and experience from endovascular abdominal aortic repair with endografts extended in the external iliac artery, it seems reasonable to expect a higher possibility of graft thrombosis in such cases.21

Coil embolization was performed in five cases at the HA’s origin and in eight cases at the HA’s distal branches. This procedure, similar to results of previous reports, resulted in mild and transient buttock claudication in 4 (30%) of 13 cases, probably because of adequate collateral circulation from the patent contralateral HA.10, 12, 13 However, the internal iliac artery’s coil embolization in cases of contralateral HA occlusion—especially the distal branches’ embolization—has been reported to cause severe pelvic ischemia and should be performed with caution.22, 23

In 28 of 33 EVIAR-treated SIAAs, the length of the proximal neck was at least 10 mm, and this allowed a secure landing in the common iliac artery and proper proximal sealing of the graft. In five cases, the proximal neck was short or aneurysmatic, and techniques within vertical iliac extensions were used (Fig 1). Furthermore, in these cases, with the currently available options of stent grafts (including iliac limbs, iliac extensions, aortouni-iliac grafts, and even aortic bifurcated protheses), the length of the proximal neck is less important for excluding patients from EVIAR treatment because of anatomic unsuitability.

Current clinical practice in both centers includes endovascular repair as first-line treatment of isolated iliac aneurysms, with the following remarks. SIAAs with short proximal necks could be treated with EVIAR using conical iliac extensions and bifurcated endovascular protheses or with retroperitoneal open repair in low-risk patients. SIAAs of the common iliac artery with good proximal and distal necks are ideal cases for EVIAR treatment. Isolated iliac aneurysms with short distal necks or with hypogastric and/or external iliac artery involvement should be treated by EVIAR, from experienced hands with precise endograft placement and adjacent techniques such as HA coil embolization. Our open series included two patients with bilateral SIAAs and involvement of both internal iliac arteries. For these cases, the open repair in low-risk patients was indicated because it ensured the revascularization of one HA or even both HAs. Finally, a second indication for open repair might be the treatment of SIAAs in young patients between the fifth and sixth decade of life. In these patients, there is an increased possibility of detecting an AAA later in life. In that case, we believe that it is beneficial to treat the AAA with endovascular techniques and that it is safer and easier to advance the aortic endograft through a conventional iliac graft than through a respective iliac endograft. Additionally, for these young and “low-risk” patients, the lifelong radiographic EVIAR follow-up might be considerably unwanted or even irritating.

Conclusions 

Although the excellent morbidity and mortality rates in this series using open repair and a retroperitoneal approach challenges the necessity of endovascular repair, there is no doubt that EVIAR resulted in better early outcomes as well as equal outcomes at mid-term (3 years) follow-up. Thus, endovascular techniques in the elective treatment of isolated iliac artery aneurysms are safe and effective and could be offered as first-line treatment of isolated iliac aneurysms, pending the results of studies with long-term follow-up.

Author contributions