The anatomy of abdominal aortic aneurysms: implications for sizing of endovascular grafts

Morphology-Related Limitations of Endovascular Aneurysm Repair Applicability in the Treatment of Abdominal Aortic Aneurysm in West-Central Poland

BACKGROUND

Morphology is one of the most important factors influencing the long-term durability of endovascular repair of an infrarenal abdominal aortic aneurysm (AAA). The knowledge of morphological characteristics of AAA that may differ in various populations seems to be important for further development of a technology of endovascular repair as well as for planning of treatment strategies. To analyze the current applicability of endovascular aneurysm repair (EVAR) in patients with an infrarenal AAA with an indication for elective treatment in west-central Poland.

METHODS

Computed tomography angiograms of 100 consecutive patients with infrarenal AAA deemed to require treatment were analyzed with an OsiriX DICOM viewer in 3D-multiplanar reconstruction mode. Proximal neck diameter, length, angulation, shape, the presence of thrombus and calcification, distal neck diameter, and morphology of the iliac arteries were determined. Three sets of morphological criteria were established. The optimal criteria consisted of a nonconical proximal neck without moderate or severe calcification or thrombus, with a diameter of 18-28 mm, length of ≥15 mm, and β angulation of <60%; a distal neck with a diameter of ≥20 mm; a landing zone in the common iliac arteries (CIAs) with a length of ≥10 mm and diameter of ≤20 mm; and external iliac arteries with diameters of ≥7 mm. The suboptimal criteria included proximal neck diameters of 18-32 mm, neck lengths ≥10 mm, infrarenal neck angulations of up to 75°, and CIA diameters of up to 25 mm. Finally, the extended suboptimal criteria included proximal neck diameters of 16-34 mm and infrarenal neck angulations ≤90°, without limits in the maximal diameter of the CIAs.

RESULTS

The median maximum aneurysm diameter was 61 mm. The optimal, suboptimal, and extended suboptimal criteria were met by 23%, 32%, and 53% of patients, respectively. The most common deviations were wide, conical, and angulated proximal necks and aneurysmal iliac arteries.

CONCLUSIONS

The majority of patients with AAA deemed to be candidates for elective repair do not meet the most favorable criteria for EVAR. Availability of better endovascular solutions for conical, angulated, and wide necks and aneurysmal iliac arteries would likely expand EVAR applicability. Open repair remains a valid option.

Natural History of the Iliac Arteries after Endovascular Abdominal Aortic Aneurysm Repair and Suitability of Ectatic Iliac Arteries as a Distal Sealing Zone

Purpose:

To investigate the natural history of dilated common iliac arteries (CIA) exposed to pulsatile blood flow after endovascular abdominal aortic aneurysm repair (EVAR) and the suitability of ectatic iliac arteries as sealing zones using flared iliac limbs.

Methods:

Follow-up computed tomograms of 102 CIAs in 60 EVAR patients were investigated. Diameter changes in CIAs ≤16 mm (group 1) were compared with changes in vessels where a dilated segment >16 mm in diameter continued to be exposed to pulsatile blood flow (group 2). Within group 2, cases in which the stent terminated proximal to the dilated artery segment (2a) were compared with those that had been treated with a flared limb (2b).

Results:

The mean CIA diameter increased by 1.0±1.0 mm in group 1 (p<0.001 versus immediately after EVAR) and by 1.5±1.7 mm in group 2 (p<0.001 versus immediately after EVAR) within an average follow-up of 43.6±18.0 months. Diameter increase was more pronounced in dilated CIAs (p=0.048), and it was not significantly different between groups 2a and 2b (p=0.188). No late distal type I endoleak or stent-graft migration associated with CIA ectasia was observed.

Conclusion:

Dilatation of the CIA is significant after EVAR, and it is more pronounced in ectatic iliac arteries. Although ectatic iliac arteries appear to be suitable sealing zones in the short term, continued follow-up is mandatory.

Endovascular Repair of Abdominal Aortic Aneurysm Using the EVT Device: Limited Increased Utilization with Availability of a Bifurcated Graft

Purpose:

To determine if the availability of a bifurcated graft would increase the percentage of patients eligible for endovascular repair of abdominal aortic aneurysms (AAAs).

Methods:

One hundred eighty-five consecutive patients were evaluated prospectively for endovascular AAA repair at a university referral center. Data were collected on eligibility for tube or bifurcated endovascular grafts, reasons for exclusion, aneurysm morphology, and the interventions performed.

Results:

Forty-six (25%) patients were eligible for endovascular treatment using the first-generation Endovascular Technologies (EVT) system: 19 (10%) for a tube graft and 27 (15%) for a bifurcated device. An unsuitable proximal neck was the reason for exclusion in 48% of patients (excess diameter in 27%, inadequate length in 21%). Unsuitable iliac configuration was present in 41% of those excluded; 29% of the common iliac arteries were enlarged or aneurysmal, while 12% were small or tortuous.

Conclusions:

Although a bifurcated graft more than doubles the eligibility of AAA patients for endovascular repair, the configuration of the proximal neck and iliac disease excluded the majority of AAA patients from endovascular therapy using the first generation EVT device.

Spiral CT Angiography versus Aortography in the Assessment of Aortoiliac Length in Patients Undergoing Endovascular Abdominal Aortic Aneurysm Repair

Purpose:

To compare measurements of aortoiliac length obtained with spiral computed tomographic angiography (CTA) and aortography in patients undergoing endovascular aneurysm repair.

Methods:

The distances from the lower-most renal artery to the aortic bifurcation and from the aortic bifurcation to the common iliac artery (CIA) bifurcation were measured using both CTA and aortography in 108 patients with abdominal aortic aneurysms.

Results:

The level of agreement between CTA and aortography was high, with 69% of aortic and 76% of iliac measurements within 1 cm and > 90% within 2 cm of each other. Mean differences were −0.35 ± 1.20 cm and 0.25 ± 1.10 cm, respectively, for aortic and iliac lengths. Aortography overestimated renal artery to aortic bifurcation length in comparison to CTA (p = 0.003), particularly in patients with large aneurysms (> 6.5 cm) and lumen diameters > 4.5 cm (p < 0.0001). Measurements of CIA length were shorter by aortography than CTA (p = 0.02).

Conclusions:

There is a high level of agreement between CTA and aortography in the measurement of aortoiliac length, but aortography overestimates renal artery to aortic bifurcation length in patients with large-diameter aneurysms and wide aneurysm lumens. CTA is sufficiently accurate in the majority of cases to be used as the sole basis for the construction of endovascular grafts.

Management of aortoiliac aneurysms by retrograde endovascular hypogastric artery preservation

We evaluated the outcome of the retrograde endovascular hypogastric artery preservation (REHAP) technique for the treatment of complex aortoiliac aneurysms (AIAs). Perioperative and long-term outcomes were assessed for 12 patients (mean age 77 years, range 64-86 years) who underwent elective endovascular AIA repair via aortouniiliac endografting and REHAP between January 2004 and January 2011. Preoperative images obtained by computed tomography were used for planning. Postoperative images were obtained one and six months after surgery, and once a year thereafter. Technical success was achieved in all cases. No patients exhibited endoleak related to the endoprosthesis, occlusion of implanted components, hip and/or buttock claudication, or colon or spinal cord ischemia during follow-up. This hybrid procedure illustrates the potential of REHAP in the treatment of AIA cases.

A Modular Aortouniiliac Endovascular Stent-graft is a Useful Device for the Treatment of Symptomatic and Ruptured Infrarenal Abdominal Aortic Aneurysms: One-year Results from a Multicentre Study

INTRODUCTION

Endovascular repair (EVAR) of acute symptomatic and ruptured abdominal aortic aneurysm (rAAA) can be difficult without a large stock of suitable graft sizes. We report a prospective European multicentre study of a modular aortouniiliac stent-graft.

PATIENTS AND METHODS

Seven centres, with elective EVAR experience, participated in the study. Sixty-five patients were enrolled from September 2002 - April 2005. Some 45 patients had rAAA and 20 were acutely symptomatic. Their median age was 74 (69-80.3) years, 49 (75%) were men. From a choice of 4 body and 4 limb sizes, stent-grafts were deployed under local or general anaesthesia.

RESULTS

The endovascular delivery system was introduced and the aneurysm excluded from the circulation in a median of 40 (30-60) minutes from the first incision. The median operative duration was 150 (120-190) mins, blood loss 300 ml (200-800). 33 (51%) operations were performed by a vascular surgeon alone. There were a total of 4 (6%) peri-operative re-interventions, endovascular (n=1), open (n=2) and thrombectomy (n=1). The peri-operative mortality in the rupture group was 40% and 10% in the symptomatic group.

CONCLUSIONS

Aortouniiliac stent-grafts provide rapid exclusion of rAAA. Suitably trained surgeons can do the operation without a radiologist's support. The mortality rate from rAAA treated with EVAR remains high.

Endovascular treatment of ruptured and symptomatic abdominal aortic aneurysms

OBJECTIVE

To report the experience of endovascular repair (ER) in patients with ruptured and symptomatic abdominal aortic aneurysms (rAAA and sAAA), comparing results with a cohort of controls who underwent open repair (OR) of sAAA or rAAA.

DESIGN

A historically controlled cohort study.

MATERIALS

Retrospective data from 21 patients who underwent ER and prospective data from 23 patients who underwent OR.

METHODS

Results were compared using the Mann-Whitney U-test.

RESULTS

Eleven ER patients had sAAAs and 10 had rAAAs. Nine OR patients had rAAAs and 13 had sAAAs. Thirty-day mortality was 11% in patients with rAAA in the ER group, and 54% in the OR group (p=0.03). There were no post-operative deaths in the patients who had an sAAA in the ER group, and one death in the patients who had sAAA in the OR group. Results as expressed as mean ER value versus mean OR value and p-value. ER was associated with significant reductions in the length of operation (2.6 versus 3.1h, p=0.03), blood transfusion requirements (0.86 versus 10.7 units p<0.01), time in critical care (1.5 versus 6.1 days, p=0.02), and total hospital stay (8.5 versus 17.5 days, p=0.01) compared with OR. There was no difference in time from admission to arrival in theatre between the two groups (3.4 versus 5.0h, p=0.35).

CONCLUSIONS

In patients with rAAA and sAAA that are suitable for stenting, ER has reduced mortality compared with open repair. Assessment for ER does not cause a pre-operative delay, operating time is reduced, blood transfusion requirements are reduced and there is a faster recovery.

Minilaparotomy for Aortoiliac Aneurysmal Disease

Vascular surgery is evolving, as other specialities, toward minimally invasive techniques. Presently, 3 approaches to aortoiliac disease are suggested as minimally invasive. Besides the endovascular procedures, laparoscopic techniques and minilaparotomy are being advocated. Although for aneurysmal disease, we favor a totally laparoscopic approach, criticisms raised over laparoscopy-assisted techniques by those advocating minilaparotomy led us to investigate the benefits of the latter technique. We first evaluated the procedure in 7 patients with infrarenal abdominal aortic aneurysm (AAA). We found the procedure impossible to perform with an 8- to 10-cm incision in 6 of the 7 patients. This led us to evaluate causes of failure of the technique. It appeared to us that most of our complications were related to inadequate exposure. Fifty consecutive computed tomography scans from patients with AAA of surgical size were then reviewed to evaluate the aneurysm lengths and compare them to the reported lengths of skin incision for minilaparotomy. Results were expressed adding a total of 2 cm for proximal and distal clamping. Only 2% of patients would present with aneurysms suitable for treatment through an 8-cm midline incision and 30% through a 10-cm incision. We then reviewed the literature on minilaparotomy. We believe that minilaparotomy should be reserved for those patients with purely aortic disease and the appropriate body habitus.

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.

Accuracy of computer-aided measurements in endovascular stent-graft planning: an experimental study with two phantoms

RATIONALE AND OBJECTIVES

The aim of this study was to evaluate the accuracy of the new measurement software, created for aortic stent-graft planning. The software finds semiautomatically the centerline of the vessel from computer tomographic angiography data and calculates semiautomatically diameters and lengths.

MATERIALS AND METHODS

Two phantoms were constructed, scanned by CT and measured with the measurement software. Results were compared with the known dimensions of the phantoms and mean fractional errors were calculated. Linear regression analysis was also made between measured and known diameters.

RESULTS

The mean fractional error (+/- SD) for all diameter measurements combined was 0.017 +/- 0.011. In the linear regression analysis, was 1.000. For length measurements, the mean fractional error (+/- SD) was 0.009 +/- 0.0006.

CONCLUSIONS

The software enables accurate measurements perpendicular or parallel to the semiautomatically created centerline path.

The endovascular management of ruptured abdominal aortic aneurysms

Endovascular aneurysm repair (EVAR) is a controversial technique, which remains the subject of a number of prospective randomised trials. Although questions remain regarding its long-term durability objective evidence exists which demonstrates its reduced physiological impact compared with conventional open repair. If this technique could be used in patients with ruptured abdominal aortic aneurysm (AAA) it may reduce the high peri-operative mortality. A review of the literature identified a limited experience with EVAR of ruptured AAA. Only a small number of case series with selected patients exist. The majority of patients were haemodynamically stable. However, the selective use of aortic occlusion balloons allowed successful endovascular management in a small number of unstable cases. All investigators had access to an "off the shelf" endovascular stent-graft (EVG). Per-operative mortality ranged from 9 to 45% and may reflect increasing experience and patient selection. A number of patients who underwent successful EVAR were turned down for open repair. A number of important lessons have been learned from these studies but questions remain regarding patient suitability and staffing issues. If these difficulties can be surmounted then the technique may offer an alternative to open repair.

Endovascular repair of ruptured abdominal aortic aneurysm--a challenge to open repair? Results of a single centre experience in 20 patients

INTRODUCTION

The mortality from ruptured abdominal aortic aneurysm (AAA) remains in the region of 50% despite advances in critical care. Endovascular repair of AAA has been shown to be associated with reduced physiological stress in the elective setting. It is hypothesised that the reduced physiological stress associated with EVAR may improve the outcome in patients with ruptured AAA.

METHODS

A feasibility study of endovascular repair of ruptured AAA was undertaken at the University Hospital, Nottingham, U.K. between 1994 and 2000. Patients admitted with ruptured AAA were assessed by a team familiar with endovascular techniques for elective repair of AAA. After giving informed consent patients underwent spiral computed tomographic angiography (CTA) in the majority of cases. Patients were then transferred to the operating theatre for EVAR.

RESULTS

Twenty patients underwent repair of ruptured AAA. Of these 20 patients, seven were referred from another hospital. Eight patients were considered unfit for open repair. The median duration of procedure was 180 min (range 120-480) and median blood loss was 1200 ml (range 750-2000 ml). The overall peri-operative mortality was 45%. A number of intra-operative and peri-operative procedures (both open and endovascular) were required to ensure aneurysm exclusion and to deal with the complications of endovascular surgery.

CONCLUSIONS

Ruptured AAA remains a particularly hazardous condition to treat. There are a number of advantages of EVAR in this condition. A number of the problems early in the experience of EVAR have been addressed, but further experience is required to demonstrate its efficacy when compared with open repair.

Adverse consequences of internal iliac artery occlusion during endovascular repair of abdominal aortic aneurysms

OBJECTIVE

Embolization of the internal iliac artery (IIA) may be performed during endovascular abdominal aortic aneurysm (AAA) repair if aneurysmal disease of the common iliac artery precludes graft placement proximal to the IIA orifice. The IIA may also be unintentionally occluded because of iliac trauma or coverage by the endograft. The purpose of this study was to determine the incidence, etiology, and consequences of IIA occlusion during endoluminal AAA repair.

METHODS

Over 2 years, 96 patients have undergone endoluminal AAA repair. The details of the operative procedure, reasons for IIA occlusion, perioperative complications, and clinical follow-up were recorded.

RESULTS

The IIA was intentionally occluded in 15 patients (16%) to treat 13 common iliac artery aneurysms, one IIA aneurysm, and one external iliac artery aneurysm. The IIA was unintentionally occluded in 9 patients (9%), resulting from traumatic iliac dissection in 5 patients and coverage of the IIA by the endograft in the remaining 4 patients. Three patients had colon ischemia. One patient with a unilateral IIA occlusion had sigmoid infarction necessitating resection. The other two patients underwent intentional occlusion of one IIA followed by unintentional occlusion of the contralateral IIA because of a traumatic iliac dissection. Both had postoperative abdominal pain and distention; rectosigmoid ischemia was revealed through colonoscopy. Conservative treatment with bowel rest and broad-spectrum antibiotics was successful in both cases. Nondisabling hip and buttock claudication occurred in seven patients (32%) at 1 month but resolved by 6 months in three of these patients.

CONCLUSION

Embolization of the IIA for iliac aneurysmal disease and unintentional IIA occlusion due to trauma or graft coverage occurs in a considerable number of patients undergoing endoluminal AAA repair. Most patients with unilateral occlusion do not experience colon ischemia or disabling claudication. Therefore, unilateral embolization of the IIA is well tolerated and allows for the endoluminal treatment of patients with both an AAA and an iliac artery aneurysm, thereby expanding the number of patients who can be managed with an endovascular approach. Although acute, bilateral IIA occlusions should be avoided, significant consequences were not observed in our small series of patients.

The value of intraoperative intravascular ultrasound for determining stent graft size (excluding abdominal aortic aneurysm) with a modular system

Since the introduction of endovascular stent grafts at our institution we have used intraoperative intravascular ultrasound (IVUS) to definitively determine stent graft size. In this study, expected stent graft size, based on preoperative helical CT scan measurements, was compared with the actual final size, based on intraoperative IVUS measurements. Between December 1996 and January 1998, 54 patients were treated with an AneuRxTM bifurcated stent graft. Preoperatively all patients underwent angiography and helical CT scanning. Expected stent graft size was determined according to these measurements. The final stent graft size was based on IVUS measurements acquired during the procedure. Differences in expected and final size were compared and follow-up endoleaks were also noted. Differences in diameter measurements between CT and IVUS were compared using the paired Student's t-test. Differences in expected and chosen stent graft length were compared using the McNemar's test for paired proportions of binomial outcomes. Our results showed that helical CT scanning overestimates diameter and underestimates length. This underestimation of length is explained by the tortuosity of the aorta and iliac arteries while using axial slices of the CT scan. The last-minute corrections based on the intraoperative IVUS measurements did not result in a high incidence of endoleaks at fixation zones. In our opinion, the possibility of making final corrections in the choice of diameter or length of the stent graft is the additional value of intraoperative IVUS.

Aortic stent-grafting with transrenal fixation: use of newly designed spiral Z-stent endograft

PURPOSE

To evaluate the feasibility and efficacy of a newly designed stent-graft placed across the renal arteries for exclusion of abdominal aortic aneurysms (AAAs) with short or tortuous proximal necks.

METHODS

Among a group of AAA patients treated with endovascular grafting, 5 had tortuous proximal necks and 13 had necks <20 mm (mean 13 mm). In these 18 cases, a 2- to 3-cm uncovered segment of the stent-graft was placed transrenally using a catheter inserted into the renal artery as a guide for graft margin positioning. A newly designed stent-graft was constructed from a custom-made spiral Z-stent covered with a thin-walled Dacron material; the endografts were deployed through 16-F (aortoaortic model) or 18-F sheaths (bifurcated devices). Renal function was assessed by preoperative and postoperative measurement of urea nitrogen and creatinine. Aneurysm exclusion and renal artery patency were evaluated during follow-up using spiral computed tomography and angiography.

RESULTS

The stent-grafts were correctly placed at the intended site in all 18 patients. Renal function was not affected except transiently in 1 patient who developed bilateral renal artery stenoses 24 hours after the procedure; Palmaz stents were deployed in each renal artery to reestablish satisfactory blood flow. Of the 33 renal arteries crossed by the bare stent-graft segment, all were patent over a mean 14-month follow-up (range 7-24), including the patient with Palmaz stents implanted for postprocedural renal stenosis. Complete aneurysm exclusion was maintained in 15 (83%) of 18 patients; proximal leaks persisted in 3 patients, including 2 with severely angled proximal necks.

CONCLUSIONS

Transrenal placement of the uncovered leading edge of custom-made spiral Z-stent-based endografts appears feasible and clinically effective in the treatment of AAAs with short or tortuous proximal necks.

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.

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

PURPOSE

To determine if the availability of a bifurcated graft would increase the percentage of patients eligible for endovascular repair of abdominal aortic aneurysms (AAAs).

METHODS

One hundred eighty-five consecutive patients were evaluated prospectively for endovascular AAA repair at a university referral center. Data were collected on eligibility for tube or bifurcated endovascular grafts, reasons for exclusion, aneurysm morphology, and the interventions performed.

RESULTS

Forty-six (25%) patients were eligible for endovascular treatment using the first-generation Endovascular Technologies (EVT) system: 19 (10%) for a tube graft and 27 (15%) for a bifurcated device. An unsuitable proximal neck was the reason for exclusion in 48% of patients (excess diameter in 27%, inadequate length in 21%). Unsuitable iliac configuration was present in 41% of those excluded; 29% of the common iliac arteries were enlarged or aneurysmal, while 12% were small or tortuous.

CONCLUSIONS

Although a bifurcated graft more than doubles the eligibility of AAA patients for endovascular repair, the configuration of the proximal neck and iliac disease excluded the majority of AAA patients from endovascular therapy using the first generation EVT device.

Endoluminal treatment of infrarenal aortic aneurysms: clinical experience with the Talent stent-graft system

PURPOSE

To evaluate the safety and efficacy of the Talent stent-graft (TSG) system in the endoluminal treatment of infrarenal abdominal aortic aneurysms (AAAs).

PATIENTS AND METHODS

Endoluminal treatment of an AAA was attempted in 30 men with a mean age of 70.5 years (range, 51-83 years). Seven patients had AAAs suitable for treatment with a tube graft. In the other patients, treatment with a bifurcated TSG was planned. All procedures were performed as a combined surgical-radiologic procedure in an angiographic room.

RESULTS

Primary technical success was achieved in 25 of 30 patients (83%). Technical failures were due to misplacement of the TSG (n = 2) with proximal leakage as a consequence, inability to gain access via the iliac arteries (n = 1), and a distal leakage (n = 2). Secondary interventions (n = 2) and spontaneous thrombosis of a distal leak (n = 1) increased the secondary technical success rate to 93% (28 of 30). Two procedures were converted to open surgery (conversion rate = 6%). One patient died during the first 30 days after uncomplicated stent-graft insertion because of myocardial infarction (30-day mortality = 5%). No complications occurred during a mean follow-up of 15.4 months (range, 6-19 months). The maximum diameter of the AAA decreased in eight patients and remained unchanged in the remaining patients. No increase in diameter was observed. No late endoleak or migration of the TSG was observed.

CONCLUSION

The TSG-system revealed satisfactory initial and early follow-up results. Treatment of AAAs with this stent-graft system is feasible. The technical success rate in carefully selected patients should be 90% or more. However, long-term observations are necessary to determine if the encouraging early results of this type of therapy can be preserved during long-term follow-up.

Spiral CT angiography versus aortography in the assessment of aortoiliac length in patients undergoing endovascular abdominal aortic aneurysm repair

PURPOSE

To compare measurements of aortoiliac length obtained with spiral computed tomographic angiography (CTA) and aortography in patients undergoing endovascular aneurysm repair.

METHODS

The distances from the lower-most renal artery to the aortic bifurcation and from the aortic bifurcation to the common iliac artery (CIA) bifurcation were measured using both CTA and aortography in 108 patients with abdominal aortic aneurysms.

RESULTS

The level of agreement between CTA and aortography was high, with 69% of aortic and 76% of iliac measurements within 1 cm and > 90% within 2 cm of each other. Mean differences were -0.35 +/- 1.20 cm and 0.25 +/- 1.10 cm, respectively, for aortic and iliac lengths. Aortography overestimated renal artery to aortic bifurcation length in comparison to CTA (p = 0.003), particularly in patients with large aneurysms (> 6.5 cm) and lumen diameters > 4.5 cm (p < 0.0001). Measurements of CIA length were shorter by aortography than CTA (p = 0.02).

CONCLUSIONS

There is a high level of agreement between CTA and aortography in the measurement of aortoiliac length, but aortography overestimates renal artery to aortic bifurcation length in patients with large-diameter aneurysms and wide aneurysm lumens. CTA is sufficiently accurate in the majority of cases to be used as the sole basis for the construction of endovascular grafts.

Initial experience with endovascular aneurysm repair: comparison of early results with outcome of conventional open repair

PURPOSE

To determine the safety, effectiveness, and problems encountered with endovascular repair of abdominal aortic aneurysm (AAA). Initial experience with endoluminal stent grafts was examined and compared with outcome for a matched concurrent control group undergoing conventional operative repair of AAA.

METHODS

Over a 3-year period, 30 patients underwent attempts at endovascular repair of infrarenal AAA. Of the 28 (93%) successfully implanted endografts, 8 were tube endografts, 8 bifurcated grafts, and 12 aortouniiliac grafts combined with femorofemoral bypass. Most of the procedures were performed in the past year because the availability of bifurcated and aortoiliac endografts markedly expanded the percentage of patients with AAA who might be treated with endoluminal methods. The follow-up period ranged from 1 to 44 months, with a mean value of 11 months.

RESULTS

Endovascular procedures demonstrated significant advantages with respect to reduced blood loss (408 versus 1287 ml), use of an intensive care unit (0.1 versus 1.75 days), length of hospitalization (3.9 versus 10.3 days), and quicker recovery (11 versus 47 days). Although the total number of postoperative complications was identical for the two groups, the nature of the complications differed considerably. Local and vascular complications characteristic of endovascular repair could frequently be corrected at the time of the procedure and tended to be less severe than systemic or remote complications, which predominated among the open surgical repair group. On an intent-to-treat basis, 23 (77%) of the 30 AAAs were successfully managed with endoluminal repair. The seven (23%) failures were attributable to two immediate conversions caused by access problems, three persistent endoleaks, one late conversion caused by AAA expansion, and one late rupture.

CONCLUSIONS

Although less definitive than those for conventional operations, these early results suggest that endovascular AAA repair offers considerable benefits for appropriate patients. The results justify continued application of this method of AAA repair, particularly in the treatment of older persons at high risk.

Common iliac artery aneurysms in patients with abdominal aortic aneurysms

OBJECTIVES

To determine the incidence of common iliac artery (CIA) aneurysms in patients with abdominal aortic aneurysms (AAA) and to evaluate the relationship between AAA and CIA diameter.

METHODS

Spiral CT angiography was used to measure the maximum diameters of the abdominal aorta and the common iliac arteries of 215 patients with AAA.

RESULTS

The median CIA diameter was 1.7 cm--significantly greater than the published mean of 1.25 (2 S.D. = 0.85-1.65) cm of an age-matched, non-vascular population. Thirty-four patients (16%) had unilateral and 26 patients (12%) bilateral CIA aneurysms > or = 2.4 cm diameter. Eight-six vessels (20%) were affected. Right CIA diameters were wider than left CIA diameters (p < 0.0001, Wilcoxon matched-pairs signed rank test). The correlation between AAA size and CIA diameter was weak.

CONCLUSIONS

The AAA population has abnormally dilated common iliac arteries. In this population, common iliac artery aneurysms should be defined as those greater than 2.4 cm diameter. 20% of CIAs in patients with AAA are aneurysmal according to this definition.