Endovascular repair of abdominal aortic aneurysm using the EVT device: limited increased utilization with availability of a bifurcated graft

Sonographic Evaluation of Aortic Endografts

The selective use of endovascular devices to repair abdominal aortic aneurysms was introduced in the early 1990s. Although placement of an aortic endograft offers patients a less morbid alternative to surgical repair, this procedure is not without complications. Persistent perfusion of the residual aneurysmal sac via endoleaks may place the patient at risk for aneurysmal enlargement and subsequent rupture. Historically, serial computed tomographic angiography has been used as the primary modality for assessment of aortic endografts. In recent years, sonography has been shown to provide a valued tool for ongoing surveillance of aortic endografts and identification of endoleaks, increasing aneurysmal size, hemodynamic disorders, and graft migration and/or kinking. Standardization of the sonographic evaluation yields accurate information vital to the long-term patency of these conduits.

Endovascular aneurysm repair with a bifurcated endovascular graft at a primary referral center: Influence of experience, age, gender, and aneurysm size on suitability

OBJECTIVE

The purpose of this study was to assess the suitability for endovascular repair of abdominal aortic aneurysm (EVAR) in an unselected patient population.

PATIENTS AND METHODS

Between February 1999 and May 2002 all consecutive patients with a nonemergent abdominal aortic aneurysm (AAA) were prospectively examined with contrast material-enhanced spiral computed tomography (CT). Those patients probably suitable for EVAR on the basis of CT findings underwent calibrated angiography. A panel of radiologists and vascular surgeons reviewed the clinical data and vascular anatomy, and decided on the appropriateness of EVAR with the bifurcated Zenith AAA endovascular graft.

RESULTS

One hundred seven patients were included. Fifty-six patients (52%) had one or more contraindications for EVAR. Unsuitability was most frequently (88%) related to the proximal neck. Inadequate neck length was the most common specific reason. Inadequate iliac anatomy was the reason for unsuitability in 59% of patients. The rate of unsuitability decreased from 61% during the first half of the study to 40% during the second half (P =.03) Unsuitability was equal between men and women. Age and maximum diameter did not differ between candidates and noncandidates.

CONCLUSION

Almost half (48%) of patients with an infrarenal AAA referred to a primary referral center are suitable for EVAR with the bifurcated Zenith AAA endovascular graft. Neck anatomy was the most frequent reason for rejection. Rate of suitability increased over time, probably as a result of increasing experience. Suitability was not influenced by gender, age, or aneurysm size.

Abdominal aortic aneurysms: elective endovascular repair versus conventional surgery--evaluation with evidence-based medicine techniques

PURPOSE

To use evidence-based techniques to compare elective open surgical repair of abdominal aortic aneurysms with endovascular repair by means of stent placement.

MATERIALS AND METHODS

A focused clinical question formed the basis of a literature search. Evidence-based criteria were used to appraise and assign a "level of evidence" to retrieved articles. The following data were determined from the best studies: systemic, local, and/or vascular complications; graft failure rates; blood loss; mortality; length of intensive care and/or hospital stay; mid- and long-term outcomes; cost of endovascular repair versus that of surgery; and eligibility for endovascular repair. Absolute risk reductions and/or increases and numbers needed to treat or harm were calculated.

RESULTS

The best current evidence came from 22 studies, which showed that there is slight, if any, difference between mortality rates of endovascular repair and surgery. Hospital and/or intensive care stay is shorter, blood loss less, and systemic complications fewer (numbers needed to treat, two to 12) with endovascular repair. Some authors reported a significant increase in local and/or vascular complications with endovascular repair (numbers needed to harm, two to six). Graft failure is significantly more common with endovascular repair (numbers needed to harm, four), and substantive adjunctive interventions are needed. Endovascular repair is more expensive than surgery.

CONCLUSION

Elective endovascular repair has short-term benefits compared with surgery. There is slight, if any, difference in mortality. Endovascular repair costs more than surgery. At follow-up, surgical grafts performed better.

Comparison of morphologic features of intact and ruptured aneurysms of infrarenal abdominal aorta

INTRODUCTION

Endovascular aneurysm repair (EVAR) has been suggested as a technique to improve outcome of ruptured abdominal aortic aneurysm (AAA). Whether this technique becomes an established treatment will depend, in part, on the anatomy of ruptured AAA.

METHODS

The anatomy of intact and ruptured AAA seen in a university department of vascular surgery over 5 years was reviewed. Aneurysm anatomy was assessed with spiral computed tomographic angiography. Suitability for EVAR was assessed from the dimensions of the proximal neck and common iliac arteries. Neck length less than 15 mm, neck width greater than 30 mm, and common iliac artery diameter greater than 22 mm were declared unsuitable for EVAR.

RESULTS

Three hundred sixty-three patients with intact AAA and 46 with ruptured AAA were identified. Larger intact aneurysms were significantly associated with longer renal artery-bifurcation distance and more complex proximal neck architecture. In this sample, patients with ruptured AAA were more likely to have larger aneurysms with shorter and narrower proximal necks. Significantly more intact aneurysms were morphologically suitable for endovascular repair compared with ruptured AAA (78% vs 43%; P <.001).

CONCLUSIONS

Ruptured AAA are less likely to be suitable for endovascular repair than are intact AAA, most probably because of larger diameter at presentation. Open repair will likely remain the treatment of choice in most patients with ruptured AAA, because of current morphologic constraints of endovascular repair.

Failure of endovascular aortoaortic tube grafts: a plea for preferential use of bifurcated grafts

OBJECTIVE

Aortoaortic tube graft repair was the first technique used for the endovascular treatment of abdominal aortic aneurysms (AAAs). However, progressive changes in the morphology of the distal aortic neck may be responsible for procedural failure. This study examines the use of aortoaortic tube prostheses and analyzes the factors that contributed to their failure and the methods used for their subsequent repair.

METHODS

During a 7-year period, 462 patients with abdominal aortic aneurysms underwent endovascular aortic aneurysm repair. Of these, 65 patients (14%) underwent treatment with aortoaortic tube endoprostheses. Aortoaortic tube prostheses used included Talent (n = 44) (Medtronic-Worldmedical, Sunrise, Fla), Vanguard (n = 8) (Boston Scientific, Natick, Mass), EVT/Ancure (n = 4) (Guidant, Menlo Park, Calif), and physician-fabricated (n = 9). All the tube graft procedures were performed in the operating room with fluoroscopic guidance. The average age of patients for aortoaortic tube grafts was 74.5 years, and 48 of the patients were men. Failure was defined as aneurysm expansion, any type I endoleak, or type II endoleak persistent after 6 months.

RESULTS

No aneurysm ruptures or perioperative deaths were seen. Retrograde aneurysm perfusion from lumbar or inferior mesenteric arteries (type II endoleak) that persisted beyond 6 months was present in three patients. Proximal attachment site endoleaks were present in two patients. No distal implantation site endoleaks were present within 1 month of the initial endovascular repair; however, endoleaks at the distal attachment site developed in 12 patients subsequently and included all graft types (Talent, n = 6; Vanguard, n = 2; Ancure/EVT, n = 1; physician-fabricated, n = 3). The average time interval to failure was 12.9 months. Preoperative distal aortic neck length showed a significant correlation with the subsequent development of distal endoleak (endoleak, 16.6 +/- 6.8 versus no endoleak, 23.3 +/- 9.6; P =.03). Preoperative distal aortic neck diameter, however, did not show significance (23.8 +/- 5.2 versus 22.6 +/- 4.7; P = not significant).

CONCLUSION

Endovascular aortoaortic tube grafts are vulnerable to failure even when initial exclusion of the aneurysm is successful. A significant association is seen between distal neck length and eventual failure. Because of the propensity toward eventual failure, the use of aortoaortic tube grafts in the infrarenal aorta cannot be recommended for typical fusiform aneurysms, even when an adequate distal neck appears to be present.

EVT endovascular graft for abdominal aortic aneurysm

BACKGROUND

A variety of prostheses are now available for the endovascular treatment of abdominal aortic aneurysm (AAA). Significant advantages of the EVT device are its unibody design, secure hook attachment system and graft fabric approximating that used in conventional surgery.

METHODS

Implantation of the EVT device was attempted in 60 patients who were studied prospectively with an analysis of subsequent problems encountered.

RESULTS

Conversion to open repair was required in four cases (6.7%). There were nine tube grafts inserted, 13 aorto-unilateral iliac with crossover grafts and 34 aorto-bi-iliac grafts. There was one death (mortality 1.7%). Endoleaks were identified in eight patients (14%), none of which were proximal; three sealed spontaneously, two were treated with coil embolization, two are being observed and one patient had an iliac attachment converted to an open anastomosis. Access vessel problems were seen in 21 patients (35%); two-thirds were corrected at the time of initial surgery. Seven patients (12%) had primary graft limb problems identified and treated before leaving the operating room. Nine patients (16%) developed secondary graft limb problems, which were diagnosed and treated after the initial surgery. Endovascular treatment was used in eight and was successful in six with surgical revision required in two. On review of these cases to assess if the problem could have been predicted at the time of initial surgery, it was felt that more aggressive treatment of intraoperatively diagnosed graft limb stenoses, even though considered mild, may have prevented 50% of subsequent secondary graft limb occlusions.

CONCLUSION

Although the EVT device has significant advantages in the endovascular management of aortic aneurysm, potential graft limb problems need to be actively identified with the majority able to be successfully managed by supplementary endovascular techniques.

The carotid artery as alternative access for endoluminal aortic aneurysm repair

Endograft treatment of aortic aneurysms has become a common procedure in many centers. However, not all patients are candidates for this new technology, because of their vascular anatomy and device limitations. One common problem is iliofemoral occlusive disease, which when present, even in a moderate degree, may preclude introduction of the large-diameter delivery devices currently in use. We present a case of a high-risk male patient with a thoracic aortic aneurysm and severe occlusive disease of the iliac arteries. An alternative approach for device delivery through the carotid artery was used and the procedure was successful with no neurologic complications. We recommend this technique for highly selected patients with an aneurysm who can undergo tube endograft repair without feasible access through the iliac or femoral arteries.

Endovascular repair of abdominal aortic aneurysms: eligibility rate and impact on the rate of open repair

OBJECTIVE

The purpose of this study was to determine the rate of eligibility among patients with abdominal aortic aneurysms (AAAs) considered for endovascular repair and to examine the effect of an endovascular program on the institutional pattern of AAA repair.

METHODS

All patients evaluated for endovascular AAA repair since the inception of an endovascular program were reviewed for determination of eligibility rates and eventual treatment. Open AAA repairs were categorized as simple (uncomplicated infrarenal), complex (juxtarenal, suprarenal, thoracoabdominal, infected), or ruptured, and their rates before and after initiation of an endovascular program were compared.

RESULTS

Over 3 years, 324 patients were considered for endovascular AAA repair; 176 (54%) were candidates, 138 (43%) were not candidates, and 10 (3%) did not complete the evaluation. The rate of eligibility increased significantly from 45% (66/148 patients) during the first half of this period to 63% (110/176 patients) during the second half (P <. 001). Candidates were significantly younger (74.4 +/- 7.6 years) than noncandidates (78.3 +/- 6.7 years) (P <.01), and their aneurysm diameter tended to be smaller (57.6 +/- 9.2 mm compared with 60.8 +/- 12.3 mm; P =.06). The most common reason for ineligibility was an inadequate proximal aortic neck. Of 176 candidates, 78% underwent endovascular repair, and 6% underwent open repair. Of 138 noncandidates, 56% underwent surgical repair. Over a period of 6 years, 542 patients with AAAs (429 simple, 86 complex, 27 ruptured) underwent open repair. The total number and ratio of simple to complex open repairs for nonruptured aneurysms during the 3 years before the initiation of the endovascular program (213 simple, 44 complex) were not significantly different from the repairs over the subsequent 3-year period (216 simple, 42 complex). Similarly, no difference in the total number and the ratio of simple to complex open repairs was found between the first and the second 18-month periods since the initiation of the endovascular program.

CONCLUSIONS

The rate of eligibility of patients with AAA for endovascular repair appears to be higher than previously reported. The presence of an active endovascular program has not decreased the number or shifted the distribution of open AAA repair.