Endovascular stent grafting in the presence of aortic neck filling defects: early clinical experience

Endovascular repair of abdominal aortic aneurysms: stent-graft fixation across the visceral arteries

PURPOSE

Recent studies have suggested that transrenal artery fixation of endovascular stent-grafts is safe and may be a desirable means of reducing the risk of type I endoleaks, particularly those with short infrarenal necks. The close proximity of the superior mesenteric and celiac arteries to the renal arteries may commonly result in the placement of the stent struts across all the vessels of the visceral segment of the aorta. The purpose of this study was to determine the incidence and impact of transvisceral artery fixation during aortic stent-graft deployment for the treatment of abdominal aortic aneurysms (AAAs).

METHODS

From January 1997 to June 1999, 192 patients (165 men, 27 women; mean age, 82 years) with AAAs were treated with an endovascular graft secured proximally to the aorta with a long (15 mm) uncovered stent segment (60 Parodi/Palmaz, 132 Talent-LPS). Preoperative and postoperative abdominal aortograms and intravenous contrast enhanced spiral computed tomography (CT) scans were performed. Follow-up CT scans were obtained at 3, 6, and 12 months and yearly thereafter as a means of determining stent position and visceral artery patency

RESULTS

In 95 patients (49%), the uncovered stent was at or above the level of the superior mesenteric artery. In 23 patients (12%), the stent extended to the level of the celiac axis. In a mean follow-up period of 25 months (range, 6-44 months), serum creatinine levels remained stable, no stenoses or occlusions occurred in the celiac, superior mesenteric, or renal arteries, and no evidence of renal, hepatic, splenic, or intestinal infarction was present on contrast enhanced spiral CT scans. There were no type I endoleaks.

CONCLUSION

Transvisceral fixation of the uncovered proximal aortic stent occurs frequently during deployment of devices designed for transrenal fixation and is associated with no early morbidity. Long-term follow-up is necessary to ensure that there are no late sequelae.

Impact of exclusion criteria on patient selection for endovascular abdominal aortic aneurysm repair

PURPOSE

Wide-ranging predictions have been made about the usefulness of endovascular repair for patients with abdominal aortic aneurysms (AAAs). The availability of US Food and Drug Administration-approved devices has removed the restrictions on patient selection, which had been controlled by device trials. This study examined the applicability of endovascular AAA repair and identified the anatomic barriers to successful endovascular AAA repair that should guide future device development.

METHODS

All patients who came to our institution for infrarenal AAA repair between April 1998 and June 2000 were offered evaluation for endovascular repair. Thin-cut spiral computed tomography scans and arteriograms were obtained on all patients, and their anatomic characteristics were prospectively entered into a database. A wide selection of available devices allowed the treatment of diverse AAA anatomic features.

RESULTS

A total of 307 patients were examined (264 men, 43 women). Of these, 204 patients (66%; 185 men, 19 women) underwent endovascular repair, and 103 patients (34%, 79 men, 24 women) were rejected. Reasons for exclusion included short aneurysm neck (56, 54%), inadequate access because of small iliac arteries (48, 47%), wide aneurysm neck (41, 40%), presence of bilateral common iliac aneurysms extending to the hypogastric artery (22, 21%), excessive neck angulation (14, 14%), extensive mural thrombus in the aneurysm neck (10, 10%), extreme tortuosity of the iliac arteries (10, 10%), accessory renal arteries originating from the AAA (6, 6%), malignancy discovered during the examination (5, 5%), and death during the examination interval (2, 2%). Rejected patients had an average of 1.9 exclusion criteria (range, 1 to 4). A disproportionate number of women were excluded because of anatomic findings (P = .0009). Although 80% of patients who were at low risk for surgery qualified for endovascular repair, only 49% of our patients who were at high risk for surgery were acceptable candidates (P < .001). Of the 103 patients who were excluded, 34 (33%) underwent open surgical repair, and the remaining 69 (67%) were deemed to be unfit for open surgery. Three patients (1.4%) failed endograft placement because of inadequate vascular access.

CONCLUSION

Most infrarenal AAAs (66%) can be treated with endovascular devices currently available commercially or through US Food and Drug Administration-approved clinical trials. However, patients who are at high risk for surgery and might benefit most from endovascular repair are less likely to qualify for the procedure (49%). Men (70%) are more likely than women (40%) to meet the anatomic criteria for endografting. Difficulties with vascular access and attachment site geometry predominate as reasons for exclusion. Our findings suggest that smaller profile devices, which can negotiate small and tortuous iliac arteries, are needed. Proximal and distal attachment site problems require devices that can accommodate wide and angulated attachment necks and achieve short seal zones.

Internal iliac artery revascularization as an adjunct to endovascular repair of aortoiliac aneurysms

PURPOSE

Endovascular repair of aortoiliac aneurysms may be limited by extension of the aneurysm to the iliac bifurcation, necessitating endpoint implantation in the external iliac artery. In such cases the circulation to the internal iliac artery is interrupted. Bilateral internal iliac artery occlusion during endovascular repair may be associated with significant morbidity, including gluteal claudication, erectile dysfunction, and ischemia of the sigmoid colon and perineum. We have employed internal iliac artery revascularization (IIR) to allow endograft implantation in the external iliac artery while preserving flow to the internal iliac artery in patients with aneurysms involving the iliac bifurcation bilaterally.

METHODS

A total of 11 IIR procedures were performed in 10 patients undergoing endovascular abdominal aortic aneurysm (AAA) repair (9 men, 1 woman; mean age, 74 years). IIR was accomplished via a retroinguinal incision in 9 cases and a retroperitoneal incision in 2 cases. Six-mm polyester grafts were used for external-to-internal iliac artery bypass in 10 cases and internal iliac artery transposition onto the external iliac artery was used in one case. Endovascular AAA repair was performed using a modular bifurcated device (Talent-LPS, Medtronics, Minneapolis, Minn) after IIR. Bypass graft patency was determined immediately after the surgery, at 1 month, and every 3 months thereafter, using duplex ultrasound scanning and computed-tomography angiography. Mean aneurysm diameters were as follows: AAA, 6.4 +/- 0.7 cm; ipsilateral common iliac, 3.7 +/- 1.0 cm; contralateral common iliac, 3.9 +/- 0.8 cm.

RESULTS

Successful IIR and endovascular AAA repair were accomplished in all cases. No proximal, distal, or graft junction endoleaks occurred. Two patients demonstrated retrograde aneurysm side-branch endoleaks originating from the lumbar arteries. One thrombosed spontaneously within 3 months. One perioperative myocardial infarction occurred. Reduction in aneurysm size was documented in 5 aortic, 5 ipsilateral iliac, and 3 contralateral iliac aneurysms. Gluteal claudication, erectile dysfunction, colon and perineal ischemia, and mortality did not occur. All IIRs have remained patent during a follow-up period of 4 to 15 months (mean, 10.1 months).

CONCLUSIONS

IIR may be used with good short-term to intermediate-term patency to prevent pelvic ischemia in patients whose aneurysm anatomy requires extension of the endograft into the external iliac artery. This may allow endovascular AAA repair to be performed in patients who might otherwise be at risk for developing complications associated with bilateral internal iliac artery occlusion.