Endovascular repair of abdominal aortic aneurysm: getting out of trouble

Straight aortic endograft in abdominal aortic disease

Background

We describe our 8-year experience with the use of endovascular techniques (ET) for the treatment of abdominal aortic aneurysms (AAA) through a straight endograft.

Methods

We retrospectively reviewed data of all patients who were treated for AAA using ET in two centres from 1998 to 2012 and who received a single straight endograft (group A) or a double straight tube (group B). Outcomes were analyzed to assess survival, absence of endoleak and absence of reintervention for both groups. Log-rank and Chi-Square were used as appropriate to make comparison between the two groups. P values < .05 were considered statistically significant.

Results

Fifty-three patients from 1998 to May 2012 were treated for AAA using a straight endograft. In 28 cases (52.8%) a single aortic straight tube was used (Group A), while in the remaining cases a “double trombone technique” was used (Group B).

Primary success was obtained in 52 cases (98.1%). In one patient of group A immediately after the operation we observed a type Ia endoleak, which was correct with a proximal aortic cuff.

Fluoroscopy time, operation time, amount of intraprocedural contrast medium and blood loss were slightly higher for group B, even if not significantly. Mortality at 30 days was nil for both groups. Mean follow-up was 49 months (range 2–153 months).

Five patients died in group A, four of them for a neoplastic disease and the remaining for aortic rupture. No patients died in group B. Endoleaks occurred more frequently in patients of group A (5 type I endoleaks and 1 type II endoleak from a lumbar artery).

Reintervention were more frequent for patients of group A, being type I endoleak the main cause. A stent fracture was observed in a patient who received EVAR by “trombone technique” 3 months later. Reintervention was then necessary and a third stent was successfully placed to cover the lesion.

Conclusions

In our experience the endovascular repair of AAA using straight aortic endografts was a safe and effective technique. Reintervention and endoleaks were slightly more frequent in patients who had received a single endograft compared to patients who were treated using the “trombone technique”.

Endovascular Repair of Abdominal Aortic Aneurysm With Extreme Iliac Artery Tortuosity

Iliac artery tortuosity can be a limiting factor in treating abdominal aortic aneurysms by endovascular means. In this case, a 6F catheter guiding sheath was used to allow tracking of the superstiff wire to straighten the iliac artery on the left. This allowed for tracking of the larger sheath so that a bifurcated device could be completed. This technique may be useful in dealing with extreme iliac tortuosity if one is unable to advance the superstiff wire.

Impact of aortoiliac tortuosity on endovascular repair of abdominal aortic aneurysms: evaluation of 3D computer-based assessment

OBJECTIVE

The purpose of this study was to examine the effect of aortoiliac tortuosity, as assessed by observers and 3-dimensional (3D) computer-based methods, on the conduct and outcome of endovascular repair of abdominal aortic aneurysms.

METHODS

Infrarenal aortoiliac tortuosity was measured in 75 patients (mean follow-up, 14.8 +/- 10.4 months) who underwent endovascular repair of abdominal aortic aneurysms by using the following four methods: (1) grading by 2 experienced observers; (2) tortuosity index measured as the inverse radius of curvature (cm(-1)) at 1-mm intervals along the median luminal centerline (MLC) on 3D reconstructions of computed tomography (CT) angiograms and was calculated as the sum of values greater than 0.3 cm(-1); (3) MLC-straight line length ratio from renal to hypogastric arteries; (4) manual measurement of angles at points of angulation on anteroposterior and lateral projections of 3D CT reconstructions. In evaluating association between these measures, correlation between human observers was accepted as the gold standard.

RESULTS

For rating of overall aortoiliac tortuosity, interobserver correlation (r = 0.67) was comparable with correlation of observers with tortuosity index (r = 0.67 and 0.56), whereas correlations of each observer with MLC-straight line ratio (r = 0.50 and 0.56) and cumulative angulation (r = 0.44 and 0.44) were significant but weaker. For determining the relative tortuosity of right and left aortoiliac access, agreement between observers and tortuosity index (54% and 58%; P < .05; kappa, 0.33 and 0.38) was not as good as between observers (68%; P < .001; kappa, 0.53). This difference was primarily related to evaluation of the aorta, where interobserver correlation (r = 0.71) was better than that between each observer and tortuosity index (r = 0.47 and 0.55), whereas correlations in the iliac arteries were comparable (r = 0.64 and 0.67) (all coefficients P < .01). Increased tortuosity was associated with a more complex endovascular repair, as reflected by longer fluoroscopy time (P = .05), use of more contrast material (P = .03), use of extender modules (P = .04), and more frequent use of arterial reconstruction (P = .01), but was not associated with a higher overall complication rate. Increased tortuosity, when it occurred in the aortic neck, was associated with predischarge endoleak (P = .03) but not with late endoleak, intervention, or aneurysm-related adverse events.

CONCLUSION

Aortoiliac tortuosity is associated with increased complexity of endovascular aneurysm repair and with predischarge endoleak but does not appear to affect intermediate-term results. Computer-based 3D measurement of aortoiliac tortuosity is feasible and clinically meaningful. Its ultimate role in relation to human assessment must be further defined in future studies.

Impact of endovascular repair for abdominal aortic aneurysms in octogenarians

A total of 50 consecutive patients (86% male; median age, 82 years) underwent endovascular repair of abdominal aortic aneurysms (AAAs) ranging from 4.0 to 9.0 cm (median, 5.2 cm). Efficacy of aneurysm exclusion was assessed by angiography, duplex scan, and/or contrast-enhanced computed tomography (CT). Acute technical success was 82%. Access failed in one patient, and immediate conversion to open operation was required in two patients. Improper deployment of the endoluminal graft (ELG) across the renal arteries occurred in one patient. The median operation time, estimated blood loss, packed red blood cells received, contrast volume, and length of intensive care and hospital stay were 128 min, 200 mL, 0.1 unit, 297 mL, 0.9 days, and 3 days, respectively. ELG limb thrombosis was seen in one patient. There were 4 (8%) early endoleaks, and 2 endoleaks were discovered in other patients at 3 and 6 months. Local/vascular and remote/systemic postoperative complications were seen in 13 (26%) and 9 (18%) patients, respectively. At a median follow-up of 11 months (range 2 to 36 months), clinical success was 78%. The aneurysm sac diameter (n = 49) decreased from a preoperative median of 5.2 to 4.7 cm (p = 0.0001). Technical success was high, and results at 11 months were satisfactory. Long-term outcomes require further study.

Ancillary techniques to facilitate endovascular repair of aortic aneurysms

PURPOSE

The ability to treat abdominal aortoiliac aneurysms and thoracic aortic aneurysms may be limited by coexisting arterial disease. Device deployment may be impaired by occlusive disease and tortuosity of the arteries used to access the aneurysm or by suitability of the implantation sites. In this study we describe the auxiliary procedures performed to circumvent these obstacles and thereby enable endovascular aneurysm repair.

PATIENTS AND METHODS

Between January 1, 1993, and December 31, 1999, 390 patients treated for aneurysm of the aorta with endovascular devices were entered prospectively in a vascular registry. Fifty (12%) of the 390 patients required adjunctive surgical techniques to (1) create or extend the length of the proximal or distal device implantation site or (2) permit device navigation through diseased iliac arteries. Auxiliary techniques used to extend or enhance implantation sites were elephant trunk graft (n = 2), the construction of renovisceral bypass grafts (n = 1), and subclavian artery transposition (n = 2). Plication of the common iliac artery at its bifurcation was performed in conjunction with femorofemoral bypass graft in nine patients to allow preservation of pelvic circulation by avoiding internal iliac artery sacrifice. Construction of a bypass graft to transpose the internal iliac artery orifice was performed in one patient. The auxiliary techniques used to facilitate device navigation were iliac artery angioplasty or stenting (n = 8), external iliac artery endovascular endarterectomy or straightening (n = 14), endoluminal iliofemoral bypass conduit (n = 5), and the construction of an open iliofemoral bypass conduit (n = 8).

RESULTS

Successful deployment of the endovascular devices was achieved in 49 (98%) of 50 patients. Auxiliary techniques were successful in providing access for endovascular device deployment in all 35 patients (100%). Mean follow-up for techniques to facilitate device navigation is 26 months for endovascular procedures and 42 months for the open bypass graft construction patients; no occlusions were observed at this moment. There were five patients with incisional hematomas that did not necessitate intervention. Fourteen (94%) of 15 patients underwent successful device implantation after the auxiliary maneuvers to enhance implantation site. Mean follow-up for implantation site manipulation is 28 months. One of the subclavian transpositions had a new onset of Horner's syndrome, two of nine patients who had common iliac artery ligated had retroperitoneal hematomas that did not necessitate interventions, and no colon ischemia was seen. The patient who underwent nonanatomic bypass grafting of viscero-renal arteries had a retroperitoneal hematoma that necessitated reexploration.

CONCLUSIONS

Significant coexisting arterial disease may be encountered in patients with aortic or iliac aneurysms. Identification of coexisting arterial diseases is essential to help tailor the appropriate supplemental surgical procedure to allow the performance of endovascular aneurysm repair in patients who would otherwise require open surgical repair.

Endoleak after endovascular repair of abdominal aortic aneurysm

PURPOSE

We sought to assess the role of endovascular techniques in the management of perigraft flow (endoleak) after endovascular repair of an abdominal aortic aneurysm.

METHOD

We performed endovascular repair of abdominal aortic aneurysm in 114 patients, using a variety of Gianturco Z-stent-based prostheses. Results were evaluated with contrast-enhanced computed tomography (CT) at 3 days, 3 months, 6 months, 12 months, and every year after the operation. An endoleak that occurred 3 days after operation led to repeat CT scanning at 2 weeks, followed by angiography and attempted endovascular treatment.

RESULTS

Endoleak was seen on the first postoperative CT scan in 21 (18%) patients and was still present at 2 weeks in 14 (12%). On the basis of angiographic localization of the inflow, the endoleak was pure type I in 3 cases, pure type II in 9, and mixed-pattern in 2. Of the 5 type I endoleaks, 3 were proximal and 2 were distal. All five resolved after endovascular implantation of additional stent-grafts, stents, and embolization coils. Although inferior mesenteric artery embolization was successful in 6 of 7 cases and lumbar embolization was successful in 4 of 7, only 1 of 11 primary type II endoleaks was shown to be resolved on CT scanning. There were no type III or type IV endoleaks (through the stent-graft). Endoleak was associated with aneurysm dilation two cases. In both cases, the aneurysm diameter stabilized after coil embolization of the inferior mesenteric artery. There were two secondary (delayed) endoleaks; one type I and one type II. The secondary type I endoleak and the associated aneurysm rupture were treated by use of an additional stent-graft. The secondary type II endoleak was not treated.

CONCLUSIONS

Type I endoleaks represent a persistent risk of aneurysm rupture and should be treated promptly by endovascular means. Type II leaks are less dangerous and more difficult to treat, but coil embolization of feeding arteries may be warranted when leakage is associated with aneurysm enlargement.

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.

Endovascular repair of aortic aneurysms: critical events and adjunctive procedures

OBJECTIVE

We sought to define the learning curve relative to the incidence and range of intraoperative problems and to establish guidelines for troubleshooting during the endovascular repair of infrarenal aortic aneurysms.

METHODS

We prospectively evaluated our first 75 consecutive cases over a 12-month period and focused on perioperative critical events and adjunctive procedures as categorical outcome measures collected during the operation. Patients were separated into three groups on the basis of the date of their operation, such that group 1 consisted of our first 25 cases, group 2 our next 25 cases, and group 3 our last 25 cases.

RESULTS

At least one critical event and adjunctive procedure marked 67 (89%) of 75 cases. In 51%, there were at least two critical events and adjunctive procedures. There were no immediate open conversions or intraoperative deaths. Access problems occurred in 28% of the 75 cases and were addressed by use of brachial-femoral artery access (30%), iliac artery/aortic bifurcation balloon angioplasty (8%), and iliofemoral conduits (4%). Graft foreshortening was the most common deployment event (44%), necessitating distal covered extensions. Iliac graft limb twists and kinks occurred in 12% of cases and were managed with balloon angioplasty and uncovered stents. General incidents included balloon ruptures (10%), arterial dissections (6%), iliac artery rupture (2.6%), and lower extremity ischemia (4%). The two cases of iliac artery rupture were managed with distal covered extensions, and there were no cases of atheroemboli. Intraoperative endoleaks were encountered in 44% of the cases and included proximal attachment sites (15%), distal attachment sites (9%), type 2 sources, and "blushes." Management of intraoperative endoleaks included proximal/distal covered extensions and re-ballooning. Our 30-day endoleak rate was 20%. The incidence of critical events did not decrease in the latter one third compared with the first two thirds of cases.

CONCLUSIONS

Critical events occur frequently during endovascular repair of aortic aneurysms. The intraoperative problems range from the common endoleaks, access and deployment issues, and balloon ruptures, to rare but life-threatening complications such as iliac artery rupture. A toolbox of accessories that includes wires, catheters, large balloons, covered proximal and distal extensions, and uncovered stents is essential given the frequency of adjunctive procedures. Successful aortic endografting requires more than mere familiarity with basic endovascular techniques.

Aortic side branch embolization before endovascular aneurysm repair: incidence of type II endoleak

PURPOSE

To assess the feasibility of embolization of aortic side branches and its impact on the incidence of type II endoleak after endovascular aneurysm repair.

MATERIALS AND METHODS

Endovascular aneurysm repair was performed in 74 patients. Aortic side branch vessels were evaluated on the preoperative angiogram and computed tomography (CT) and, where embolization of lumbar and inferior mesenteric vessels was considered technically possible, this was attempted prior to endovascular repair. Follow-up CT was used to assess the presence of type II endoleak.

RESULTS

Seventy-two patients were followed up for longer than 1 month. Embolization was attempted in 25 cases, successfully in 10, with partial success in 11, and failure in four. Twenty patients with successful or partly successful preoperative embolization were discharged and followed-up. Four (20%) had demonstrable type II endoleak during follow-up, with two of these persisting at latest follow-up. Of 43 patients without previous embolization, there were 10 (23.3%) type II endoleaks during the follow-up period, four of these persisting. In cases with type II endoleak, mean sac diameter change was -0.5 mm in the cases with previous embolization and +3.1 mm without. The mean period to onset of type II endoleak was 6.9 months without, and 15.3 months with, previous embolization.

CONCLUSION

Although the cohort size is below a level that would confer significance, the trend of these findings is such as to suggest a lack of influence of aortic side branch embolization on the incidence of type II endoleak during the follow-up period.

Endovascular Treatment of Aortic Disease

A review is given of endovascular treatment for AAA, thoracic aortic aneurysms, dissections as well as complications following previous aortic surgery. In several of these conditions endovascular treatment has advantages like a reduced operative trauma, shorter stay in hospital, and the possibility of treating patients who would have been unfit for open surgery. On the other hand, problems like endoleak, deformation of the endoprosthesis, retrograde filling of the aneurysmal sack, and graft limb occlusion need to be solved before the place of endovascular treatment can be defined. It is possible that the steadily improving quality of the implants as well as the introducer systems will widen the indications for endovascular surgery, but randomised clinical trials are warranted and a longer follow-up period is necessary to draw final conclusions.

Special iliac artery considerations during aneurysm endografting

BACKGROUND

The feasibility of endograft exclusion of abdominal aortic aneurysms (AAA) has been established. However, the technical challenges of graft delivery through tortuous or diseased iliac arteries and the treatment of associated iliac aneurysmal disease have received little attention.

METHODS

Over 19 months, 74 patients underwent endoluminal repair of AAA and/or iliac artery aneurysms. Iliac anatomy that required special consideration during endografting was reviewed.

RESULTS

Of the 74 patients, 35 (47%) had iliac anatomy that required special attention. Thirteen patients (18%) had aneurysmal involvement of a common iliac artery. Eleven of these patients required endograft extension into the external iliac artery (EIA) and hypogastric coil embolization due to the proximity of the aneurysm to the hypogastric origin. Eleven patients with ectatic, nonaneurysmal iliac arteries required aortic cuffs to achieve a distal seal in these oversized vessels. Iliac artery tortuosity or stenosis were complicating factors in 27 of the 74 patients (36%), requiring the use of brachial guidewire tension in 2 patients to facilitate tracking of the delivery device. Five patients with severely splayed aortic bifurcations required crossed placement of the iliac limbs to prevent kinking of the endograft. Occlusive atherosclerotic disease of the EIA mandated preprocedural dilatation and stenting in 3 patients and postprocedural surgical EIA reconstruction in another 5 patients. Three patients who underwent successful endograft placement required subsequent endovascular repair of traumatized EIAs.

CONCLUSIONS

Iliac artery anatomy plays a significant role in the endoluminal treatment of infrarenal abdominal aortic aneurysms, complicating the procedure in up to 47% of patients with otherwise suitable anatomy. A variety of supplemental procedures, both surgical and endovascular, may be required to facilitate endograft placement. A special understanding of these constraints and proper planning is required for optimal therapy.