An RCT to compare a bio-cellulose wound dressing with a non-adherent dressing in VLUs.

OBJECTIVE: To compare the efficacy of a bio-cellulose dressing (BWD) versus a non-adherent wound contact layer in venous leg ulcer (VLU) outpatients. METHOD: In a prospective, randomised, controlled multicentre study, 48 VLU patients were randomised to receive compression bandages and either standard care (non-adherent dressing; n=23) or a BWD (Suprasorb X; n=25). VLUs were evaluated for debridement efficacy, time to 75-100% granulation and ≥ 50% re-epithelialisation, reduction of ulcer size and patient-reported ulcer pain, comparing the status at day 0 and weekly, over a 12-week study treatment period. RESULTS: Thirty-three patients (n=18 BWD and n=15 control dressing) were included in the analysis. Autolytic debridement was significantly faster in the BWD group, with an 84% removal of yellow tissue compared with 26% in the control group, over the 12-week period (p < 0.0001). A median of 25 days were required to achieve 75-100% granulation in the BWD group vs 36 days for controls. A median of 36 days was taken to achieve ≥ 50% re-epithelialisation in the BWD group vs 50 days for controls. Patient-reported ulcer pain reduced significantly faster in the BWD group (p < 0.05), by week 7, 100% of patients reported no pain, compared with 63% of controls. CONCLUSION: Autolytic debridement was faster and more effective in the BWD group compared with standard care, as was pain reduction. Although the time to healing was shorter with the BWD vs standard care, the difference was not statistically significant. DECLARATION OF INTEREST: This study was supported by Xylos Corporation. The study product was called X-Cell at the time, and is now available as Suprasorb X (Lohmann & Rauscher). Each principal investigator (Alvarez, Phillips, Menzoian, Etris-Brown) and respective clinical centre received funding for the conduct of the study. Each site executed a clinical study agreement independently with the sponsor. The sponsors had no role in the design and conduct of the study, in the collection, analysis, or interpretation of data, or in the preparation of the manuscript, review, or approval of the manuscript. None of the authors received administrative, technical or material support for the conduct of this study. The authors have no relevant financial interest in this article.

Changes in cellular motility and cytoskeletal actin in fibroblasts from patients with chronic venous insufficiency and in neonatal fibroblasts in the presence of chronic wound fluid.

PURPOSE: Fibroblasts (fb) play an important role in wound healing involving motility, contraction, fibrosis, and expression of the cytoskeletal protein alpha-smooth muscle actin (alpha-sma). Patients with chronic venous insufficiency (CVI) are known to have dermal changes and impaired venous ulcer healing. To investigate whether these dermal-fb have an altered ability to migrate and whether chronic wound fluid from venous ulcers alters neonatal fb motility, we examined cell migration and alpha-sma. METHODS: Fibroblasts were cultured from the margin of venous ulcers (du-fb, n = 4, CEAP 6), from patients with venous reflux without ulcer (dr-fb, n = 5, CEAP 2), and from the ipsilateral thigh of the same patients with (pu-fb) and without (pr-fb) ulcer, respectively. The abbreviations used are p and d, which represent proximal and distal, respectively; u and r represent ulcer and reflux, respectively. Neonatal foreskin fibroblasts (nf-fb) were exposed to chronic venous ulcer wound fluid (CVUWF, 300 microg protein/mL, n = 3) or bovine serum albumin (BSA, control). Fibroblast motility was determined by means of time-lapse photo-images, and the rate (micrometer per hour) was calculated. Immunohistochemistry for alpha-sma was analyzed with confocal laser microscopy. RESULTS: The rate of motility (micrometer per hour +/- SEM) was decreased for both du-fb (11.4 +/- 0.7) and dr-fb (13.8 +/- 0.6), when compared with pu-fb (21.9 +/- 0.9) and pr-fb (24.7 +/- 1.1), respectively. The motility rate for nf-fb was lower in CVUWF (24.7 +/- 2.0) than in BSA (37.1 +/- 6.7). An elevated level of microfilament bundles of alpha-sma for both du-fb and dr-fb, compared with those of pu-fb and pr-fb, and also in nf-fb treated with CVUWF was demonstrated by means of immunohistochemistry. CONCLUSION: These data demonstrate a reduced motility in the dermal fb of patients with CVI. Patients with reflux disease without ulcer are predisposed to these changes. Furthermore, it appears that CVUWF causes changes in motility and alpha-sma expression in nf-fb as demonstrated in du-fb. These findings suggest that reduced motility and CVUWF, representing the microenvironment of venous ulcers, play a significant role in impaired wound healing.

An anterior tibial artery aneurysm in a patient with neurofibromatosis.

Von Recklinghausen's Type 1 neurofibromatosis (NF) is a genetic disorder of neuroectodermal tissue. Arterial involvement has also been recognized. Stenotic lesions predominate, but aneurysms have been documented as well. Aortoiliac, visceral, and cervical aneurysms are well represented in the literature. Rarely noted, however, have been peripheral aneurysms. Typically in more proximal vessels, subclavian, femoral, and popliteal aneurysms have been mentioned. We present the case of a patient with type 1 NF and an anterior tibial artery aneurysm that was subsequently resected. neurofibromatous invasion of the vessel was confirmed by means of pathological tests. We think this is the first reported case of a tibial artery aneurysm associated with NF.

The role of a nurse case manager in implementing a critical pathway for infrainguinal bypass surgery.

BACKGROUND: A previous study showed the effectiveness of a clinical pathway for infrainguinal bypass surgery in reducing postoperative length of stay (LOS) in an acute care setting. Most of the deviations from the pathway were due to patient factors (50%) and/or external disposition problems (30%), but 20% were related to physician or system problems that could potentially be modified. The current study examined those factors influencing LOS following infrainguinal bypass surgery and the impact of daily rounds by a nurse case manager--a vascular nurse specialist--on LOS and pathway deviations. METHODS: Data were collected through detailed chart review and prospective tracking of pathway deviations. LOS was compared in 58 patients on the modified pathway (with the nurse case manager) to 69 patients on the original pathway and 67 prepathway controls. Multivariate analysis was used to identify factors influencing postoperative LOS and to compare LOS among the three groups. RESULTS: Use of a nurse case manager significantly reduced physician-related deviations, from the pathway from 10% to 0% (p = .015), and reduced system-related deviations from 3% to 0%. Median postoperative LOS was 7 days before the pathway was begun, 6 days with the original pathway, and 5 days after the introduction of a vascular nurse specialist (p = .0001). There were no differences in rates of complications, rates of readmission, or mortality. CONCLUSIONS: Intervention by a nurse case manager facilitated implementation of a critical pathway for patients undergoing infrainguinal bypass surgery, especially by preventing patient deviations due to intrainstitutional factors.

Contrast-enhanced moving-table MR angiography: prospective comparison to catheter arteriography for treatment planning in peripheral arterial occlusive disease.

PURPOSE: Prospective comparison of contrast-enhanced moving-table magnetic resonance (MR) angiography to catheter arteriography in endovascular and surgical treatment planning in patients with peripheral arterial occlusive disease. MATERIALS AND METHODS: Thirteen patients scheduled for catheter arteriography for lower extremity arterial occlusive disease underwent contrast-enhanced moving-table MR angiography immediately prior to arteriography. A treatment plan was determined by the vascular surgeon, based on MR angiography, who was blinded to the catheter arteriogram. The treatment plan determined by the MR angiogram was compared to the final treatment plan, which was based on the catheter arteriogram and intraluminal pressure measurements. RESULTS: Treatment plans based on MR angiography and catheter arteriography were identical in 10 of 13 patients (71%). For identifying lesions resulting in intervention, MR angiography had sensitivity of 100% and a positive predictive value of 92%. MR angiography had a treatment specific predictive value of 88% for each lesion identified, and 95% for lesions identified in patients evaluated for claudication. If treatment plans were based on MR angiography only, 46% of patients would have avoided catheter arteriography. CONCLUSION: Contrast-enhanced moving-table MR angiography may be an effective alternative to catheter arteriography in endovascular and surgical treatment planning in selected patients with peripheral arterial occlusive disease, but larger studies are necessary to confirm this.

The proliferative capacity of neonatal skin fibroblasts is reduced after exposure to venous ulcer wound fluid: A potential mechanism for senescence in venous ulcers.

PURPOSE: We have previously shown that fibroblasts cultured from venous ulcers display characteristics of senescence and have reduced growth rates. Susceptibility of young fibroblasts to the microcirculatory changes associated with venous ulcers, such as macrophage trapping and activation, could explain the prevalence of senescent fibroblasts in these wounds. METHODS: We tested the in vitro effect of venous ulcer wound fluid (VUWF), as well as pro-inflammatory cytokines known to be present in VUWF (TNF-alpha, IL-1beta, and TGF-beta1), on neonatal foreskin fibroblasts (NFFs). NFF growth rates, cellular morphology, and senescence-associated beta-galactosidase (SA-beta-Gal) activity were determined in the presence or absence of VUWF and the above cytokines. VUWF TNF-alpha concentration and the effect of anti-TNF-alpha antibody on VUWF inhibitory activity were determined in samples obtained from four patients with venous ulcers. RESULTS: NFF growth rates were significantly reduced by VUWF (42,727 +/- 6301 vs 3902 +/- 2191 P =. 006). TNF-alpha also significantly reduced NFF growth rates in a dose-dependent manner (P =.01). No significant growth-inhibitory activity was seen for IL-1alpha or TGF-beta. Incubation with VUWF significantly increased the percentage of SA-beta-Gal-positive fibroblasts in vitro on culture day 12 (P =.02). TNF-alpha and TGF-beta1 had similar effects. TNF-alpha was detected in all VUWF tested, with a mean of 254 +/- 19 pg/mL. CONCLUSION: These data suggest that the venous ulcer microenvironment adversely affects young, rapidly proliferating fibroblasts such as NFFs and induces fibroblast senescence. Pro-inflammatory cytokines such as TNF-alpha and TGF-beta1 might be involved in this process. The role of other unknown inhibitory mediators, as well as pro-inflammatory cytokines, in venous ulcer development and impaired healing must be considered.

The effect of passage number on fibroblast cellular senescence in patients with chronic venous insufficiency with and without ulcer.

BACKGROUND: Fibroblasts (fb) cultured from venous ulcer patients and patients with venous reflux disease without ulcer demonstrate characteristics of cellular senescence, such as increased fibronectin level and senescence-associated beta-galactosidase (SA beta-gal) positive cells. Cellular senescence is an in vitro event characterized by the progressive loss of proliferative capacity with increased passage number, and has been associated with impaired healing in vivo. This report examines progressive stages of cellular senescence in fb from the distal area (du-fb) and proximal fb (pu-fb) of patients with venous ulcer, as well as in distal fb (dr-fb) and proximal fb (pr-fb) from patients with venous reflux without ulcer, by comparing the population doubling time (T) and percent SA beta-gal expression. RESULTS: The mean value of T over 6 passages for fb in the ulcer group was 132.5 +/- 29.0 hours for pu-fb and 492.9 +/- 146.2 hours for du-fb (P = 0.0009). For fb in the reflux group the mean value of T over 5 passages was 79.3 +/- 12.8 hours for pr-fb and 94.2 +/- 16.8 hours for dr-fb (P = 0.8). Comparing ulcer and reflux fb, no difference in T was observed between pu-fb and pr-fb (P = 0.6), but a difference was noted between du-fb and dr-fb (P = 0.0004). The mean percent SA beta-gal activity for fb in the ulcer group was 11.2% +/- 3.1% for pu-fb and 63.8% +/- 8.9% for du-fb (P = 0.0001). Individual passages demonstrated significant difference (P <0.05) in SA beta-gal activity between pu-fb and du-fb at early and late passages. No difference was noted in SA beta-gal activity for fb in the reflux group or between pu-fb and pr-fb, but comparison between du-fb and dr-fb was significant (63.8% +/- 8.9% versus 7.8% +/- 2.9%; P = 0.0001). CONCLUSIONS: The in vitro passage of du-fb and pu-fb in chronic venous ulcer patients has an effect on T and cellular senescence as measured by SA beta-gal activity. Our data further suggest that du-fb are at a more progressive stage of cellular senescence when compared with pu-fb, and more importantly with fb cultured from patients with venous reflux without ulcer. These findings are consistent with impaired wound healing of venous stasis ulcer. The accumulation of senescent fb and a more advanced stage of cellular senescence of du-fb may explain why repeated episodes of venous ulceration are resistant to conservative treatment and require more aggressive measures of therapy.

The hemodynamics of steal syndrome and its treatment.

A 61-year-old man developed steal syndrome after creation of a transposed basilic vein arteriovenous fistula (AVF) resulting in rest pain and ischemic ulcers in the fingertips. Our initial surgically created stenosis reduced the diameter by 32% and the area by 56%, and increased the radial artery pressure from 52 to 78 mmHg, with relief of symptoms. Within 3 weeks his symptoms reappeared. Repeat measurements did not explain his return of symptoms. A second area of stenosis was created in the AVF, with a diameter reduction of 75%, and an area reduction of 94%. His symptoms resolved, and his ulcers healed. The hemodynamics of the AVF and the steal syndrome were evaluated by duplex imaging and Doppler pressure assessment. A greater stenosis increased the radial artery pressure from 78 to 140 mmHg while maintaining flow through the AVF. Rather than increasing the degree of stenosis at the first site, we created a second area of stenosis. Hemodynamically, this would be additive to the first without the risk of creating a high-grade stenosis that could thrombose the AVF. Increasing the resistance in the AVF will decrease flow in the AVF and, ultimately, increase flow to the hand.

Systemic treatment of venous leg ulcers with high doses of pentoxifylline: efficacy in a randomized, placebo-controlled trial.

Several small studies have indicated that the systemic administration of pentoxifylline may accelerate healing of venous leg ulcers. The goal of this study was to further evaluate these findings in a larger scale placebo controlled trial and to explore the effect of the dose of pentoxifylline on healing. The study used a prospective, randomized, double-blind, parallel group placebo controlled design in a multicenter outpatient setting. Patients with one or more venous ulcer were enrolled, with all patients receiving standardized compression bandaging for treatment for their ulcers. Patients were also randomized to receive either pentoxifylline 400 mg, pentoxifylline 800 mg (two 400 mg tablets), or placebo tablets three times a day for up to 24 weeks. The main outcome measure was time to complete healing of all leg ulcers, using life table analysis. The study was completed as planned in 131 patients. Patients receiving 800 mg three times a day of pentoxifylline healed faster than placebo (p = 0.043, Wilcoxon test). The median time to complete healing was 100, 83, and 71 days for placebo, pentoxifylline 400 mg, and pentoxifylline 800 mg three times a day, respectively. Over half of all patients were ulcer free at week 16 (placebo) and at week 12 in both pentoxifylline groups. Whereas the placebo group had only achieved complete healing in half of the cases by week 16, all of the subjects remaining in the group receiving the high dose of pentoxifylline had healed completely. Treatment with pentoxifylline was well tolerated with similar drop-out rates in all three treatment groups. Complete wound closure occurred at least 4 weeks earlier in the majority of patients treated with pentoxifylline by comparison to placebo. A higher dose of pentoxifylline (800 mg three times a day) was more effective than the lower dose. We conclude that pentoxifylline is effective in accelerating healing of leg ulcers.

Fibroblasts cultured from distal lower extremities in patients with venous reflux display cellular characteristics of senescence.

PURPOSE: Venous reflux precedes the development of venous ulcers. Our earlier work showed that the fibroblasts that are cultured from these wounds display more characteristics of senescence. We evaluated fibroblast senescence in patients with venous reflux but without ulcers to further investigate the role of venous reflux in the predisposition to venous ulcers. METHODS: Fibroblasts that were isolated from skin biopsy specimens of the "gaiter" area (distal) and of the ipsilateral thigh of the same patient (proximal) were compared. Twelve patients with venous reflux (9 patients in clinical, etiologic, anatomic, and pathologic classification 4; 3 patients in classification 5) with an average venous filling index of 5.45 mL/s and 4 patients without venous reflux were enrolled in the study. The growth rates, the response to basic fibroblast growth factor (b-FGF), and the senescence markers (beta-galactosidase activity at a pH level of 6, unstimulated fibroblasts fibronectin protein, and messenger RNA levels) were determined for each cell population. RESULTS: The number of senescence-associated beta-galactosidase positive cells (8.3% +/- 1.9% vs 2.2% +/- 0.8%; P =.008) and the level of cellular fibronectin protein (455.7 +/- 80 vs 210 +/- 51; P =.04) and messenger RNA (16.8 +/- 6.8 vs 13.5 +/- 5.7; P =.042) were significantly higher in the distal fibroblasts as compared with the proximal fibroblast cultures. The growth rates of the distal fibroblasts were lower when compared with the proximal fibroblasts (15,746 +/- 4287 cells/day vs 29,550 +/- 5035 cells/day; P <.002) but were not different in the presence of b-FGF (41,717 +/- 9542 cells/day vs 47,030 +/- 6133 cells/day; P =.53). In the patients without venous reflux, no site differences were noted in the growth rates or the senescence markers between the proximal and distal fibroblasts. CONCLUSION: Distal fibroblasts that are isolated from patients with venous reflux display more senescence characteristics than do proximal fibroblasts and have significantly lower growth rates. Despite senescence, b-FGF restored the distal-fibroblasts growth rate to that of the stimulated proximal fibroblasts, which proposes a therapeutic role for b-FGF. These changes precede ulcer formation and suggest a mechanism that is focal and intrinsically related to venous reflux.

Carotid endarterectomy in a patient with anterior ischemic neuropathy.

A case of anterior ischemic optic neuropathy (AION) associated with 90% stenosis of the ipsilateral internal carotid artery (ICA) and diminished blood flow through the ophthalmic artery was studied. After carotid endarterectomy (CEA), the patient showed subjective and measurable improvement in vision and increased ophthalmic artery flows. This observation supports the role for screening carotid duplex scanning and transcranial Doppler in patients with AION. Early CEA in patients with associated ipsilateral ophthalmic artery hypoperfusion may improve visual outcome.

Fibroblasts cultured from venous ulcers display cellular characteristics of senescence.

PURPOSE: A well-recognized characteristic of venous ulcers is impaired healing. Fibroblasts cultured from venous ulcers (wound-fb) have been shown to have reduced growth rates and are larger than normal fibroblasts (normal-fb) from the ipsilateral limb. Reduced growth capacity and morphologic changes are 2 well-known traits of cellular senescence. Other molecular changes are overexpression of matrix proteins, such as cellular fibronectin (cFN), and enhanced activity of beta-galactosidase at pH of 6.0 (senescence associated beta-Gal, or SA-beta-Gal). Senescence, an irreversible arrest of cell proliferation with maintenance of metabolic functions, may represent in vivo aging and thus may be related to impaired healing. METHODS: Cultured normal-fb and wound-fb from 7 venous ulcer patients (average age, 51 years) were obtained by taking punch biopsies of the perimeter of the ulcer and from the ipsilateral thigh of the same patient. Growth rates, SA-beta-Gal activity, and level of cFN protein (immunoblot) and message (Northern blot) were measured. RESULTS: In all patients, wound-fb growth rates were significantly lower than those of normal-fb (P =.006). A higher percentage of SA-beta-Gal positive cells were found in all wound-fb (average, 6.3% vs. 0.21%; P =.016). The level of cFN, was consistently higher in all wound-fb tested. Also, in 4 patients, the level of cFN messenger RNA (mRNA) was increased. CONCLUSION: Fibroblasts cultured from venous ulcers exhibited characteristics associated with senescent cells. Accumulation of senescent cell in ulcer environment may be associated with impaired healing.

Coronary artery bypass grafting in patients with cerebrovascular disease.

The incidence of carotid artery disease in patients undergoing coronary artery bypass grafting appears to be increasing as our population ages. The optimal treatment for these high-risk patients with concomitant carotid and coronary artery disease remains controversial. This review focuses on the management of patients with coexistent carotid and coronary arteriosclerosis. The significance and management of the patient with an asymptomatic carotid stenosis in patients undergoing coronary artery bypass grafting and the role of combined coronary artery bypass grafting and carotid endarterectomy in these patients will be discussed.

An association between periodontal disease and peripheral vascular disease.

BACKGROUND: Periodontal disease has been shown to be associated with increased risk of coronary heart disease. Because coronary heart disease and peripheral vascular disease (PVD) have similar pathophysiologies, we hypothesized that periodontal disease might be a risk factor for PVD. METHODS: Using the combined data from the Normative Aging Study and Dental Longitudinal Study of the US Department of Veterans Affairs, we examined the relationship between PVD and periodontal disease. Multivariate logistic regression analysis was used. RESULTS: Over the 25 to 30 years of follow-up, 80 of these initially healthy subjects developed PVD. Compared with controls (n = 1,030), subjects with clinically significant periodontal disease at baseline had a 2.27 increment in the risk of developing PVD (95% confidence interval 1.32 to 3.9, P value = 0.003). CONCLUSIONS: Periodontal disease emerged as a significant independent risk factor for PVD in a multivariate analysis that adjusted for other established risk factors.

Impact of a critical pathway on postoperative length of stay and outcomes after infrainguinal bypass.

PURPOSE: To determine the effect of a critical pathway on postoperative length of stay and outcomes after infrainguinal bypass. METHODS: A critical pathway for care of patients after infrainguinal bypass was introduced in December 1995 to coordinate postoperative care at our institution. We compared care of 67 consecutively treated patients before institution of the pathway with care of 69 consecutively treated patients with the critical pathway in place. Data collection was done by means of chart review. Univariate analyses were used to identify differences between prepathway and postpathway patients and to identify factors influencing postoperative length of stay. Multivariate analysis was used to identify factors that influenced length of stay and to examine the effect of use of the pathway after adjusting for other factors. RESULTS: Patients on the pathway were similar to prepathway controls with respect to comorbid illnesses, vascular risk factors, indications for surgical treatment, type of conduit, and type of operation. Factors associated with longer postoperative stays included distal anastomoses to tibial rather than popliteal vessels (p = 0.02), preexisting cardiac disease (p = 0.005), postoperative complications (p = 0.0003), lower preoperative hematocrit (p = 0.01), and elevated preoperative creatinine level (p = 0.006). Overall, pathway patients had somewhat shorter postoperative lengths of stay (median value 7 days; range 2 to 29 days) than prepathway patients (median value 6 days; range 2 to 35; p = 0.01), and the two groups had similar frequencies of postoperative complications, readmission, and 6-month mortality. However, patients on the pathway were more likely to be discharged to an intermediate-care facility rather than directly home. After 12 patients with extraordinarily prolonged postoperative stays were excluded, multivariate analysis indicated that pathway patients had significantly shorter postoperative stays (p = 0.001). However, the difference was not significant if patients with extraordinarily long postoperative stays were included in the analysis (p = 0.28). CONCLUSION: Use of a critical pathway was associated with a modest decrease in postoperative length of stay for most patients. This was accomplished without an adverse effect on readmission, complication, or mortality rates. However, the decrease in stay may have been achieved primarily by discharging more patients to intermediate-care facilities. The pathway did not appear to have any effect when the subset of patients with extraordinarily long stays because of complex medical problems was included.

Response of normal aorta to endovascular grafting: a serial histopathological study.

OBJECTIVE: To examine the histological changes caused by the presence of the endovascular stented graft in the native aorta. DESIGN AND INTERVENTION: Case series. Twenty Western crossbred adult male sheep underwent endovascular placement of an infrarenal aortic stented graft, using the Bard aortic aneurysm repair device catheter delivery system (Bard Vascular Systems, Dovermill, Mass). Six self-expanding wire hooks at the proximal anchor allow fixation to the aorta. After 1 month (n=6), 3 months (n=6), and 6 months (n=8), the animals underwent repeated angiography and intravascular ultrasonography to study the aorta and the graft. The aorta was explanted en bloc with the left renal artery, pressure perfused with a formalin gluteraldehyde solution, and then underwent histological examination with hematoxylin-eosin, trichrome, and elastic tissue staining. MAIN OUTCOME MEASURES: Description of histological changes at various intervals after endovascular stented graft placement. RESULTS: Significant histological findings include (1) complete incorporation of the grafts into the aortic wall, with a pseudointima of smooth muscle cells and collagen; (2) a foreign-body reaction around the graft; (3) an organized blood clot noted between the graft and the aortic wall, without evidence of recent blood flow through the perigraft space or the lumbar vessels; and (4) focal replacement by collagen of the inner one third to one half of the media at the proximal anchor sites. CONCLUSION: There was good incorporation of the graft without evidence of pressure necrosis, bleeding around the graft, or flow in the occluded lumbar vessels.

A new generation endovascular graft for repair of abdominal aortic aneurysms.

BACKGROUND: Several endovascular grafts are currently being evaluated for repair of abdominal aortic aneurysms (AAA). The goals of our study were twofold. First was to develop a new endovascular graft with several advantages over previous devices: (1) smaller size (16 fr), (2) recapturability (the device can be partially deployed and then recaptured and moved to a new location or entirely removed if needed), and (3) accuracy and ease of placement. Our second goal was to develop an animal model in which a full-scale prototype of the device could be tested. METHODS: Our final endovascular graft prototype was developed after extensive in-vitro testing, and trials of earlier prototypes in dog, pig, and female sheep models. Uncastrated male sheep, 75 to 100 kg, were chosen as the animal model in which to test the device. These animals had infrarenal aortas that were comparable to that of small humans, with diameters of 12 to 15 mm. Two models were used: (1) native infrarenal aorta, and (2) artificial infrarenal aneurysm. Pre-implant and postimplant angiography and intravascular ultrasound were used to evaluate graft placement, and were repeated prior to euthanasia and necropsy. RESULTS: The final prototype was implanted in 22 animals. Sixteen animals had the device placed in their native infrarenal aorta. Three animals were sacrificed immediately after implantation, and 6 more were euthanized after 2 weeks (n = 2), 6 weeks (n = 2), and 3 to 4 months (n = 2). In 7 animals the device is still in place. All procedures were successful. Pathology confirmed complete exclusion of the aorta and thrombosis of all lumbar branches covered by the graft. There was no evidence of graft malposition, migration, or perigraft leak, and no evidence of significant vessel injury on histology. Six animals had artificial aneurysms surgically created and then repaired with the device. A technical error resulted in a failure in 1 case; the remaining aneurysms were all successfully excluded. CONCLUSIONS: We report the development of a new endovascular prosthesis for the repair of AAA. Newer design features provide for smaller delivery size (16 fr), facilitate accurate placement, and provide the option when the device is partially deployed to recapture and reposition the device if necessary. In addition, we have developed an animal model in which this device, and future endovascular aortic devices, can be tested.