Nature and significance of endoleaks and endotension: summary of opinions expressed at an international conference

OBJECTIVE

Endoleaks and endotension are critically important complications of some endovascular aortic aneurysm repairs (EVARs). For the resolution of controversial issues and the determination of areas of uncertainty relating to these complications, a conference of 27 interested leaders was held on November 20, 2000.

METHODS

These 27 participants (21 vascular surgeons, five interventional radiologists, one cardiologist) had previously answered 40 key questions on endoleaks and endotension. At the conference, these 40 questions and participant answers were discussed and in some cases modified to determine points of agreement (consensus), near consensus (prevailing opinion), or disagreement.

RESULTS

Conference discussion added two modified questions for a total of 42 key questions for the participants. Interestingly, consensus was reached on the answers to 24 of 42 or 57% of the questions, and near consensus was reached on 14 of 42 or 33% of the questions. Only with the answers to four of 42 or 10% of the questions was there persistent controversy or disagreement.

CONCLUSION

The current endoleak classification system with some important modifications is adequate. Types I and II endoleak occur after 0 to 10% and 10% to 25% of EVARs, respectively. Many (30% to 100%) type II endoleaks will seal and have no detrimental effect, which never or rarely occurs with type I endoleaks. Not all endoleaks can be visualized with any technique, and increased pressure (endotension) can be transmitted through clot. Aneurysm pulsatility after EVAR correlates poorly with endoleaks and endotension. An enlarging aneurysm after EVAR mandates surgical or interventional treatment. These and other conclusions will help to resolve controversy and aid in the management of these vexing complications and should also point the way to future research in this field.

Efficacy of a bifurcated endograft versus open repair of abdominal aortic aneurysms: a reappraisal

OBJECTIVE

Late complications and graft failures have recently cast serious doubts on the durability of endovascular repair of abdominal aortic aneurysms (AAA). The results of a multicenter trial comparing a bifurcated endograft (AB) with standard open repair (OR) were reviewed to assess the late findings of both methods of AAA treatment.

PATIENTS AND METHODS

In a multicenter study of AB versus OR conducted from December 1995 to February 1998, 242 patients with AAA successfully treated with an AB and 111 control patients treated concurrently with OR were followed up at least yearly. Twenty-five immediate conversions were excluded from late follow-up. All imaging modalities obtained during follow-up were reviewed by a core laboratory for AAA size, endoleaks, migration, and device integrity. Clinical outcomes at the yearly visits were compared. All death reports were reviewed to classify the cause of death.

RESULTS

Average follow-up for the AB group was 36 months, with 194 patients at 3 years and 55 patients at 4 years. The cumulative mortality rate was similar between the AB (15.7%) and OR groups (12.6%; P =.59). The significant early benefit to the AB group in cardiopulmonary complications was no longer evident by 3 years. However, the AB advantage in total and bowel complications, as well as the higher renal complication rates, persisted. At 3 years, 73.7% of patients showed a significant reduction of their AAA size, whereas 25.7% still had an endoleak. One migration and two single hook fractures were noted. Graftrelated reinterventions were performed in 50 patients (20%) without any deaths. Twenty-eight patients (11.6%) underwent interventions for limb flow compromise, whereas 25 were treated for endoleak. Late conversion to OR was required in five patients (2%). No AAA ruptures were encountered in either group.

CONCLUSIONS

Rupture-free survival rates after treatment of AAA with the bifurcated AB are similar to those of the OR group. Notably the proximal attachment system is relatively stable and the AAA shrinks in three of four patients treated. Reinterventions are nonetheless required in nearly one of five patients. Although most late procedures are percutaneous, counseling regarding possible future interventions is necessary.

Can the internal iliac artery be safely covered during endovascular repair of abdominal aortic and iliac artery aneurysms?

Aneurysmal involvement of the common iliac (CIA) or the internal iliac arteries (IIA) have been relative contraindications for safe endovascular aortic aneurysm (AAA) repair. Our goal was to review our experience in dealing with this problem by performing permanent coverage of one or both IIA during endoluminal repair of aneurysms of the aortoiliac region and to develop a safe, durable strategy. Of the 228 consecutive patients who had endoluminal repair of abdominal aortic (AAA) and iliac artery (IAA) aneurysms between 4/1999 and 4/2001 at our institution, 49 patients underwent coverage and/or coil embolization of one or both IIA during repair because of complex aortoiliac anatomy. These patients were evaluated prospectively for short-term adverse outcome. The results showed that CIA or IIA aneurysms can be managed safely during endoluminal repair of AAA. The IIA can be covered or embolized with minimum adverse consequences in patients who have inadequate CIA for deployment of the aortic or iliac endograft. Unilateral IIA occlusion is well tolerated. We advocate that whenever bilateral IIA occlusion is necessary during endovascular aneurysm repair, one of the IIAs should be revascularized if it is not aneurysmal.

Endoleak: predictive value for aneurysm growth at 3 years

Endoleak is a unique radiographic finding after endovascular aneurysm repair. The prognostic implication of endoleak on aneurysm therapy outcome is unknown. Patients with 3 years of follow-up were examined to determine the predictive value of endoleak, as determined by the treating physician, for aneurysm growth. Patients enrolled in a clinical trial for a unibody, bifurcated endovascular graft (Ancure-Guidant/EVT, Menlo Park, CA) were examined with respect to endoleak, as determined by the primary investigator, and aneurysm diameter change. A total of 80 patients were available at 3 years for evaluation. CT scans and ultrasound were used to determine endoleak at discharge, at 6 months, and annually. Patients were categorized as no leak (NL; n = 59), early leak (EL, leak identified by 6 months; n = 15), and late leak (LL, leak identified at 12 months or later; n = 6). A change of 5 mm in transverse diameter relative to the original diameter was used to determine an increase or decrease. Therapeutic intervention for endoleak was analyzed separately in each group. From the results we were able to determine that most patients with distal type 1 or type 2 endoleak have shrinking or stable aneurysms. Endoleak is a poor predictor of aneurysm growth but is statistically associated with enlargement. Absence of endoleak is strongly, but not entirely, predictive of lack of aneurysm growth. Endoleak is a risk factor for aneurysm enlargement, warranting further investigation to examine the etiology of the image, but cannot be used as an endpoint for effective endovascular aneurysm treatment.

Exclusion of accessory renal arteries during endovascular repair of abdominal aortic aneurysms

OBJECTIVE

Adequate proximal neck length is important for proper endovascular treatment of abdominal aortic aneurysms (AAAs). Placement of endografts in AAAs with relatively short proximal necks may require covering the origin of accessory renal arteries. Exclusion of these arteries carries the theoretical concern of regional renal ischemia associated with loss of parenchyma or worsening hypertension. We reviewed our experience with accessory renal exclusions during endovascular AAA repair to determine the frequency and severity of complications.

METHODS

Complete records were available for review on 311 of 325 consecutive patients treated with endovascular grafts for AAAs from February 6, 1996, to March 15, 2001. The presence of accessory renal arteries was ascertained from preoperative/intraoperative aortography or from computed tomographic scanning. Sizes of the accessories were measured by using the main renal arteries as a reference. Considerations for excluding the accessory renal arteries were based on the likelihood of successful proximal attachment to healthy aorta, an accessory vessel whose size does not exceed the diameter of the main renal artery, and the absence of renal disease.

RESULTS

The mean follow-up was 11.5 months. Fifty-two accessory renal arteries were documented in 37 patients (12%), ranging from 1 to > or =3 per patient. Of these, 26 accessory renal arteries were covered in 24 patients. Patients ranged in age from 57 to 85 years (mean, 74.1 years), with 20 men and 4 women. The Ancure device was used in 23 patients and the Excluder device in one. Of the accessories excluded, 22 originated above the aneurysm and 4 originated directly from the aneurysm itself. There were no perioperative mortalities. One patient died 5 months after surgery from an unrelated condition. There was one type I (distal) endoleak and no type II endoleaks. Five patients (21%) had segmental renal infarction associated with the side of accessory renal artery exclusion. Only one patient with segmental infarction had significant postoperative hypertension that resulted in changes in blood pressure medication. The blood pressure reverted to normal 3 months later. One patient with a stenotic left main renal artery required exclusion of the accessory renal artery for successful proximal attachment. Serum creatinine levels remained unchanged throughout follow-up in all but one patient, in whom progressive postoperative renal failure developed despite normal renal flow scan, presumably from intraoperative manipulation and contrast nephropathy.

CONCLUSION

Exclusion of accessory renal arteries to facilitate endovascular AAA repair appears to be well tolerated. Long-term sequelae seem infrequent and mild.

Quality of life assessment in patients undergoing endovascular or conventional AAA repair

PURPOSE

To compare health-related quality of life outcomes in a cohort of abdominal aortic aneurysm (AAA) patients treated concurrently with either a conventional or endoluminal intervention.

METHODS

Between December 1997 and April 1999, 51 AAA patients treated by either open or endovascular techniques were enrolled in this prospective study. Conventional therapy was performed in 26 patients (19 men; mean age 70.4 +/- 6.0 years) with anatomical features unsuitable for the endovascular approach. Twenty-five patients (23 men; mean age 70.7 +/- 7.2 years) underwent endoluminal AAA exclusion using either the Ancure or bifurcated Enduring stent-grafts. The Medical Outcomes Study Short-Form 36-item health survey was administered preoperatively and at 1, 4, 8, and > or = 52 weeks after discharge.

RESULTS

At 1 week, both groups showed significant reductions (p < 0.001) in mean scores compared to baseline in 4 dimensions (physical function, social function, role-physical, and vitality), but the decline was more pronounced in patients having open repair. Endoluminal patients returned to their baseline scores by the 4th postoperative week, whereas complete recovery to baseline in the conventional patients was delayed to the 8th week.

CONCLUSIONS

Patients treated endoluminally exhibit better physical and functional scores as early as 1 week after discharge; they also return to baseline status significantly earlier than the conventional group. These findings document the perceived advantage of endovascular therapy over conventional AAA treatment.

Association of intraluminal thrombus in abdominal aortic aneurysm with local hypoxia and wall weakening

PURPOSE

Our previous computer models suggested that intraluminal thrombus (ILT) within an abdominal aortic aneurysm (AAA) attenuates oxygen diffusion to the AAA wall, possibly causing localized hypoxia and contributing to wall weakening. The purpose of this work was to investigate this possibility.

METHODS

In one arm of this study, patients with AAA were placed in one of two groups: (1) those with an ILT of 4-mm or greater thickness on the anterior surface or (2) those with little (< 4 mm) or no ILT at this site. During surgical resection but before aortic cross-clamping, a needle-type polarographic partial pressure of oxygen (PO2) electrode was inserted into the wall of the exposed AAA, and the PO2 was measured. The probe was advanced, and measurements were made midway through the thrombus and in the lumen. Mural and mid-ILT PO2 measurements were normalized by the intraluminal PO2 measurement to account for patient variability. In the second arm of this study, two AAA wall specimens were obtained from two different sites of the same aneurysm at the time of surgical resection: group I specimens had thick adherent ILT, and group II specimens had thinner or no adherent ILT. Nonaneurysmal tissue was also obtained from the infrarenal aorta of organ donors. Specimens were subjected to histologic, immunohistochemical, and tensile strength analyses to provide data on degree of inflammation (% area inflammatory cells), neovascularization (number of capillaries per high-power field), and tensile strength (peak attainable load). Additional specimens were subjected to Western blotting and immunohistochemistry for qualitative evaluation of expression of the cellular hypoxia marker oxygen-regulated protein.

RESULTS

The PO2 measured within the AAA wall in group I (n = 4) and group II (n = 7) patients was 18% +/- 9% luminal value versus 60% +/- 6% (mean +/- SEM; P <.01). The normalized PO2 within the ILT of group I patients was 39% +/- 10% (P =.08 with respect to the group I wall value). Group I tissue specimens showed greater inflammation (P <.05) compared with both group II specimens and nonaneurysmal tissue: 2.9% +/- 0.6% area (n = 7) versus 1.7% +/- 0.3% area (n = 7) versus 0.2% +/- 0.1% area (n = 3), respectively. We found similar differences for neovascularization (number of vessels/high-power field), but only group I versus control was significantly different (P <.05): 16.9 +/- 1.6 (n = 7) vs 13.0 +/- 2.3 (n = 7) vs 8.7 +/- 2.0 (n = 3), respectively. Both Western blotting and immunohistochemistry results suggest that oxygen-regulated protein is more abundantly expressed in group I versus group II specimens. Tensile strength of group I specimens was significantly less (P <.05) than that for group II specimens: 138 +/- 19 N/cm2 (n = 7) versus 216 +/- 34 N/cm2 (n = 7), respectively.

CONCLUSION

Our results suggest that localized hypoxia occurs in regions of thicker ILT in AAA. This may lead to increased, localized mural neovascularization and inflammation, as well as regional wall weakening. We conclude that ILT may play an important role in the pathology and natural history of AAA.

Adenovirus-mediated gene transfer of human inducible nitric oxide synthase in porcine vein grafts inhibits intimal hyperplasia

OBJECTIVE

The aim of this study is to determine whether adenoviral inducible nitric oxide synthase (iNOS) gene transfer could inhibit intimal hyperplasia (IH) in porcine internal jugular veins interposed into the carotid artery circulation.

METHODS

Porcine internal jugular veins were transduced passively with 1 x 10(11) particles of an adenoviral vector carrying either the human iNOS (AdiNOS) or beta-galactosidase (AdlacZ) cDNA for 30 minutes and then interposed into the carotid artery circulation. Segments of each vein graft were maintained in an ex vivo organ culture to measure nitrite accumulation, a marker of nitric oxide synthesis. The grafts were analyzed immunohistochemically for the presence of neutrophils, macrophages, and leukocytes by staining for myeloperoxidase, ED1, and CD45, respectively, at 3 (n = 4) and 7 (n = 4) days. Morphometric analyses and cellular proliferation (Ki67 staining) were assessed at 3 (n = 4), 7 (n = 4), and 21 days (n = 8).

RESULTS

AdlacZ-treated vein grafts demonstrated high levels of beta-galactosidase expression at 3 days with a gradual decline thereafter. Nitrite production from AdiNOS-treated vein grafts was approximately fivefold greater than AdlacZ-treated grafts (P =.00001). AdiNOS or AdlacZ treatment was associated with minimal graft inflammation. Cellular proliferation rates were significantly reduced in AdiNOS-treated grafts as compared with controls at both 3 (41%, P =.000004) and 7 days (32%, P =.0001) after bypass. This early antiproliferative effect was most pronounced at the distal anastomosis (65%, P =.0005). The iNOS gene transfer reduced the intimal/medial area ratio in vein grafts at 7 (36%, P =.009) and 21 days (30%, P =.007) versus controls. This inhibition of IH was again more prominent in the distal segments of the grafts (P =.01).

CONCLUSION

Adenovirus-mediated iNOS gene transfer to porcine internal jugular vein grafts effectively reduced cellular proliferation and IH. Although iNOS gene transfer reduced IH throughout the entire vein graft, the most pronounced effect was measured at the distal anastomosis. These results suggest potential for iNOS-based genetic modification of vein grafts to prolong graft patency.

Outcome events in patients with claudication: a 15-year study in 2777 patients

OBJECTIVE

The purpose of this study was to delineate the natural history of claudication and determine risk factors for death.

METHODS

We reviewed the key outcomes (death, revascularization, amputation) in 2777 male patients with claudication identified over 15 years at a Veterans Administration hospital with both clinical and noninvasive criteria. Patients with rest pain or ulcers were excluded. Data were analyzed with life-table and Cox hazard models.

RESULTS

The mean follow-up was 47 months. The cohort exhibited a mortality rate of 12% per year, which was significantly (P <.05) more than the age-adjusted US male population. Among the deaths in which the cause was known, 66% were due to heart disease. We examined several baseline risk factors in a multivariate Cox model. Four were significant (P <.01) independent predictors of death: older age (relative risk [RR] = 1.3 per decade), lower ankle-brachial index (RR = 1.2 for 0.2 change), diabetes requiring medication (RR = 1.4), and stroke (RR = 1.4). The model can be used to estimate the mortality rate for specific patients. Surprisingly, a history of angina and myocardial infarction was not a significant predictor. Major and minor amputations had a 10-year cumulative rate less than 10%. Revascularization procedures occurred with a 10-year cumulative rate of 18%.

CONCLUSIONS

We found a high mortality rate in this large cohort and four independent risk factors that have a large impact on survival. Risk stratification with our model may be useful in determining an overall therapeutic plan for claudicants. A history of angina and myocardial infarction was not a useful predictor of death, suggesting that many patients in our cohort presented with claudication before having coronary artery symptoms. Our data also indicate that claudicants have a low risk of major amputation at 10-year follow-up.

The Ancure endografting system: an update

The Ancure endografting system (Guidant Cardiac and Vascular Division, Menlo Park, Calif) features a unibody, nonsupported woven polyester graft designed to treat abdominal aortic aneurysms. It is constructed in tube, bifurcated, and aortoiliac configurations. The attachment system consists of a frame with four independent V-shaped double hooks that penetrate the arterial wall for fixation. There are separate attachment systems at the proximal and distal ends of the endoprosthesis. In September 1999, the Food and Drug Administration (FDA) approved the tube and bifurcated devices for general use. The aortoiliac device is under present consideration of the FDA. Phase II and III clinical trials of the system enrolled over 870 patients from the end of 1995 to the summer of 1999. The device was deployed successfully in 90% to 96% of cases, depending on the configuration and the phase of the trial. Mortality rates were similar to those of concurrent open surgical control rates, but serious morbidity was reduced. Long-term follow-up of the bifurcated group from phase II showed only one migration and no ruptures. Aneurysm size reduction in this group was noted in 51.3% of patients at 1 year and 68.5% at 2 years. In the same subset, type I endoleaks were noted in 2.7% at 1 year and 1.3% at 2 years. All postoperative imaging studies were reviewed by a core laboratory facility. The advantages of the ancure system include solid fixation, flexibility in accommodating morphologic changes, and excellent long-term clinical performance. The disadvantages include a large introducer system and the potential for limb obstruction by compression or angulation. However, limb compromise responds well to intraluminal stenting. The expected FDA approval of the aortoiliac device and a larger variety of graft sizes should expand the number of patients who can be treated with this system.

Is proximal aortic neck dilatation after endovascular aneurysm exclusion a cause for concern?

PURPOSE

The purpose of this study was to evaluate the extent and frequency of dilatation of the proximal aortic neck over time after endovascular exclusion of abdominal aortic aneurysms and the effect on the continued integrity of the repair.

METHODS

Patients enrolled in the multicenter tube and bifurcated trials of the Guidant-Endovascular Technologies Ancure endografting system and at least 1 year of follow-up were reviewed. Neck diameter measurements were obtained from computed tomography scans that were obtained with and without contrast by an independent core laboratory facility. The diameter was considered to be the minor axis of the first slice at which point at least one half of the proximal attachment frame was located. A change exceeding 2.5 mm was considered to be significant.

RESULTS

At 1 year, 13% of the patients (42/314 patients) showed evidence of proximal neck dilatation, with a mean diameter increase of 4.8 +/- 2.4 mm. The proportion of patients with dilatation increased to 21% at 2 years (48/226 patients) and 19% at 3 years (11/59 patients). The initial presence of an endoleak, the neck length, and the aneurysm size had no clear effect on the development of neck enlargement. Initial neck diameter was inversely related to and the strongest predictor of later dilatation. Graft oversizing was not an independent predictor of neck dilatation on multivariate analysis. Only one migration of the proximal attachment system was observed during follow-up.

CONCLUSION

Most proximal aortic necks remain stable, but approximately 20% of necks increase in diameter by 2 years. Smaller necks dilate more often than larger ones. This effect is independent from the frequent oversizing of grafts in smaller necks. The integrity of the repair remains good at 3 years of follow-up.

Endovascular repair of an aortoduodenal fistula

PURPOSE

To demonstrate the utility of endovascular stent-graft repair for the management of an unusual aortoduodenal fistula.

METHODS AND RESULTS

A 23-year-old man with an aortoduodenal fistula secondary to tumor necrosis was treated with a Corvita endoluminal stent-graft after several failed surgical attempts to repair the defect. At 2-year follow-up, the patient was clinically and radiographically devoid of any evidence of occult stent-graft infection.

CONCLUSIONS

This case illustrates the usefulness of endovascular repair for the treatment of a primary aortoduodenal fistula. Endovascular repair should be included in the armamentarium for the management of difficult aortoduodenal fistulas.

Long-term fate of the aneurysmal sac after endoluminal exclusion of abdominal aortic aneurysms

PURPOSE

Shrinkage of an abdominal aortic aneurysm (AAA) is the hallmark of successful endoluminal treatment. Our goal was to prospectively assess the midterm to long-term shrinkage of the AAA sac after endovascular repair.

METHODS

A total of 123 patients with AAA underwent endoluminal treatment with the Ancure device at our institution between February 1996 and February 2000. At least a 1-year follow-up was available for 70 of the 123 patients. AAA sac size, presence of endoleaks, calcifications, and outcome data were collected on these patients at 6, 12, 24, and 36 months after repair and compared with the preoperative AAA size and characteristics. All endoleaks found at the 6-month follow-up visit were treated aggressively with embolotherapy. An AAA sac regression of 0.5 cm or more was considered the minimum measurable decrease. Regression of the sac diameter to 3.5 cm or less was considered a complete collapse of the sac.

RESULTS

Successful endoluminal repair was accomplished in 119 of 123 patients. The mortality rate was 0.8% (1/123). There was a steady decrease in AAA sac size from baseline (5.56 +/- 0.1 cm), to 6 months (5.0 +/- 0.14 cm, P =.0006), to 12 months (4.65 +/- 0.13 cm, P =.04), and to 24 months (4.26 +/- 0.16 cm, P =.03). At 24 months, 74% (29/39) had a decrease in sac size of 0.5 cm or more, with 28% (11/39) complete collapse. Patients with initial endoleaks had the same likelihood of regression of sac size (> or = 0.5 cm) when compared with the group of patients with no endoleaks at the 24-month evaluation (64% vs 76%, P =.09).

CONCLUSION

Endoluminal AAA repair resulted in a significant reduction in sac size that continues up to 2 years. Significant shrinkage occurs as early as 6 months after placement. The initial presence of endoleaks does not predict the lack of sac regression.

Is routine use of the intensive care unit after elective infrarenal abdominal aortic aneurysm repair necessary?

INTRODUCTION

Postoperative care after infrarenal abdominal aortic aneurysm (AAA) repair has traditionally involved admission to the intensive care unit (ICU). With the advent of endovascular AAA repair, the management of open procedures has received increased scrutiny. We recently modified our AAA clinical pathway to include selective use of the ICU.

METHODS

Consecutive elective infrarenal AAA repairs performed by members of the vascular surgery division at a university medical center from 1994 to 1999 were analyzed retrospectively with a computerized database, the Medical Archival Retrieval System. Group I consisted of 245 patients who were treated in the ICU for 1 or more days, and Group II included 69 patients admitted directly to the floor. Ruptured, symptomatic, suprarenal, endovascular, and reoperative repairs were excluded. Outcome variables were compared over the 6-year period.

RESULTS

Floor admissions increased over the study period with 0%, 0%, 3.3%, 16.3%, 48.6%, and 43.6% of patients admitted directly to the surgery ward from 1994 to 1999. The average ICU length of stay declined from 4.6 to 1.2 days, whereas the hospital length of stay decreased from 12.5 to 6.8 days from 1994 to 1999. The change in ICU use had no effect on death (2.4% in Group I vs 0% in Group II). Major and minor morbidity was comparable. Hospital charges were significantly lower for patients in Group II.

CONCLUSION

A policy of selective utilization of the ICU after elective infrarenal AAA repair is safe. It can reduce resource use without a negative impact on the quality of care.

Is color-flow duplex a good diagnostic test for detection of isolated calf vein thrombosis in high-risk patients?

Color-flow duplex scanning (CDS) is a good diagnostic test for lower extremity proximal deep vein thrombosis (DVT). This report aims to evaluate the diagnostic accuracy of CDS in detecting isolated calf DVT in two in-hospital populations. A total of 166 patients had routine DVT testing with both CDS and venography: 99 total joint arthroplasty patients and 67 symptomatic in-hospital patients. Isolated calf DVT was noted in 34% of arthroplasty patients and 12% of symptomatic in-hospital patients. Peroneal DVT was most common. The sensitivity, specificity, positive predictive value, and negative predictive value (with 95% confidence interval [CI]) of CDS in detecting isolated calf DVT in the symptomatic in-hospital group was 39% (16%-62%), 98% (94%-99%), 88% (65%-99%), and 81% (71%-91%), respectively. In the arthroplasty patients these values were 13% (3%-23%), 92% (85%-99%), 60% (30%-90%), and 55% (45%-65%), respectively. CDS has a low sensitivity in detecting isolated calf DVT among hospitalized patients and cannot be deemed an effective tool for identifying clots limited to only one or two tibial vessels.

Endovascular repair of an aortoduodenal fistula

PURPOSE

To demonstrate the utility of endovascular stent-graft repair for the management of an unusual aortoduodenal fistula.

METHODS AND RESULTS

A 23-year-old man with an aortoduodenal fistula secondary to tumor necrosis was treated with a Corvita endoluminal stent-graft after several failed surgical attempts to repair the defect. At 2-year follow-up, the patient was clinically and radiographically devoid of any evidence of occult stent-graft infection.

CONCLUSIONS

This case illustrates the usefulness of endovascular repair for the treatment of a primary aortoduodenal fistula. Endovascular repair should be included in the armamentarium for the management of difficult aortoduodenal fistulas.

The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators

BACKGROUND

We previously reported the prevalence and associations of abdominal aortic aneurysm (AAA) in 73451 veterans aged 50 to 79 years who underwent ultrasound screening.

OBJECTIVE

To understand the prevalence of and principal positive and negative risk factors for AAA, and to assess reproducibility of our previous findings.

METHODS

In the new cohort of veterans undergoing screening, 52 745 subjects aged 50 to 79 without history of AAA underwent successful ultrasound screening for AAA, after completing a questionnaire on demographics and potential risk factors.

RESULTS

We detected AAA of 4.0 cm or larger in 613 participants (1.2%; compared with 1.4% in the earlier cohort). The direction and magnitude of the important associations reported in the first cohort were confirmed. Respective odds ratios for the major associations with AAA for the second and for the combined cohorts were as follows: 1.81 and 1.71 for age (per 7 years), 0.12 and 0. 18 for female sex, 0.59 and 0.53 for black race, 1.94 and 1.94 for family history of AAA, 4.45 and 5.07 for smoking, 0.50 and 0.52 for diabetes, and 1.60 and 1.66 for atherosclerotic diseases. The excess prevalence associated with smoking accounted for 75% of all AAAs of 4.0 cm or larger in the total population of 126 196. Associations for AAA of 3.0 to 3.9 cm were similar but tended to be somewhat weaker.

CONCLUSIONS

Our findings confirm our previous cohort findings. Age, smoking, family history of AAA, and atherosclerotic diseases remained the principal positive associations with AAA, and female sex, diabetes, and black race remained the principal negative associations.

Yield of repeated screening for abdominal aortic aneurysm after a 4-year interval. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators

BACKGROUND

Little is known about the rate at which new abdominal aortic aneurysms (AAAs) develop or whether screening older men for AAA, if undertaken, should be limited to once in a lifetime or repeated at intervals.

METHODS

A large population of veterans, aged 50 through 79 years, completed a questionnaire and underwent ultrasound screening for AAA. Of these, 5151 without AAA on the initial ultrasound (defined as infrarenal aortic diameter of 3.0 cm or larger) were selected randomly to be invited for a second ultrasound screening after an interval of 4 years. Local records and national databases were searched to identify deaths and AAA diagnoses made during the study interval in subjects who did not attend the rescreening.

RESULTS

Of the 5151 subjects selected for a second screening, 598 (11.6%) had died (none due to AAA), and 20 (0.4%) had an interim diagnosis of AAA. A second screening was performed on 2622 (50.9%), of whom 58 (2.2%; 95% confidence interval, 1.6%-2.8%) had new AAA. Three new AAAs were 4.0 to 4.9 cm, 10 were 3.5 to 3.9 cm, and 45 were 3.0 to 3.4 cm. Independent predictors of new AAA at the second screening included current smoker (odds ratio, 3.09; 95% confidence, 1.74-5.50), coronary artery disease (odds ratio, 1.81; 95% confidence interval, 1.07-3.07), and, in a separate model using a composite variable, any atherosclerosis (odds ratio, 1.97; 95% confidence interval, 1.16-3.35). Adding the interim and rescreening diagnosis rates suggests a 4-year incidence rate of 2.6%. Rescreening only in subjects with infrarenal aortic diameter of 2.5 cm or greater on the initial ultrasound would have missed more than two thirds of the new AAAs.

CONCLUSIONS

A second screening is of little practical value after 4 years, mainly because the AAAs detected are small. However, the incidence that we observed suggests that a second screening after longer intervals (ie, more than 8 years) may provide yields similar to those seen in initial screening and therefore warrants further study.

Endovascular treatment of iliac limb stenoses or occlusions in 31 patients treated with the ancure endograft

PURPOSE

The authors report their experience with treatment of iliac limb complications in patients treated with the Ancure endograft with Wallstents to provide additional support and thrombolysis when needed.

MATERIALS AND METHODS

From February 1996 to October 1999, 88 patients were treated for abdominal aortic aneurysm with use of the Ancure endograft. Of the 88 devices used, 20 were tube grafts and the remaining 68 devices had a total of 130 iliac limbs (bifurcated, n = 62; aortoiliac, n = 6). After graft deployment, all patients underwent intraoperative aortography; since July 1997, intravascular ultrasound (IVUS) has also been used.

RESULTS

Thirty-one patients (46%) required treatment of 47 (36%) limbs with Wallstents. Graft narrowing was observed in 41 limbs (27 patients) with IVUS immediately after graft deployment. All were successfully treated with placement of Wallstents. Before routine use of intraoperative IVUS, three patients presented between 2 and 6 weeks postoperatively with iliac limb thrombosis. All three limbs were successfully treated with thrombolysis and Wallstent placement to correct the underlying iliac problem. Additionally, two contralateral limbs in these three patients were also noted to have stenosis and were treated with use of Wallstents. The last patient required placement of a Wallstent to treat stenosis of surgical anastomosis of the iliac limb of an aortoiliac endograft at 3 days. All Wallstent-reinforced Ancure endografts remained patent from 1 to 36 months (mean, 14 months).

CONCLUSION

After placement of an Ancure bifurcated or aortoiliac endograft, iliac limb stenosis is easily detected with use of intraoperative IVUS. Such complications can be safely corrected with Wallstent placement. Postoperative limb occlusion at the authors' institution has been eliminated with such intervention.

Endovascular repair of the abdominal aortic aneurysm with the ancure endograft: CT follow-up of perigraft flow and aneurysm size at 6 months

PURPOSE

Perigraft flow--flow outside the graft lumen but contained within the abdominal aortic aneurysm (AAA)--is a potential complication after endovascular repair of AAA. Such flow may permit AAA growth and rupture. The purpose of this study is to evaluate with computed tomography (CT) the rate of spontaneous closure of perigraft flow and the effect of persistent flow on AAA diameter.

MATERIALS AND METHODS

During a 30-month period, the authors evaluated all CT scans in 50 patients who underwent AAA repair using the Ancure endograft system. CT was performed at discharge, 6, 12, and 24 months, and at 3 months if there was perigraft flow at discharge. Scans were reviewed for the presence, size, and location of perigraft flow, and measurement of AAA diameter. Transcatheter embolization was performed on those patients with persistent leak at 6 months.

RESULTS

Sixteen (32%) of 50 patients demonstrated perigraft flow on CT performed within 72 hours of placement. Resolution of perigraft flow by 6 months was found in nine (56%) of the 16 patients, in whom AAA size had decreased in five, had increased in none, and was unchanged in four. Seven patients had persistent leaks at 6-month CT; AAA size had decreased in one, had increased in one, and was unchanged in five. In 34 patients without leaks, AAA size had decreased in nine, had increased in one, and was unchanged on 24. There was no statistically significant difference for the relationship between resolution or persistence of perigraft flow and subsequent course of AAA diameter (P = .16).

CONCLUSIONS

Although perigraft flow is frequently seen (32%) early after repair of AAA with the Ancure system, spontaneous resolution by 6 months occurs in 56% of cases. AAA size decreased in a larger percentage of patients in whom perigraft leak was absent or resolved by 6 months compared with those in whom perigraft leak persisted at 6 months.