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STUDY DESIGN A retrospective study. OBJECTIVE To determine the incidence of pedicle screws close to vital structures and to identify patient or curve characteristics that increase the risk of screw misplacement. SUMMARY AND BACKGROUND Most pedicle screw misplacements are asymptomatic, thus they are frequently undetected. This study identifies the rate of screw placement in proximity to vital structures using postoperative computed tomography scans. METHODS A total of 2132 screws in 101 patients, who underwent posterior spinal fusion for spinal deformity, were reviewed. Screws adjacent to great vessels and viscera were identified and evaluated. Patients with screws at risk (group B) were compared with patients without screws at risk (group A). Patient and curve characteristics were analyzed to determine whether a correlation with screw misplacement exists. RESULTS A total of 40 at risk screws (∼2%) were identified in 25 patients (∼25%). These 40 screws were in proximity to the aorta (31), left subclavian artery (1), esophagus (3), trachea (3), pleura (1), and diaphragm (1). Of the 31 screws close to the aorta, 10 screws in 6 patients were impinging or distorting the aortic wall. One hundred percent of misplaced screws were in the thoracic spine, 50% were misplaced laterally, 50% were 35 mm long, 57.5% were in pedicles with normal morphology, and 75% were in curves between 40 and 70 degrees. Median screw misplacement rate was 10% in group A and 13% in group B. Adjusted for age and preoperative Cobb angle, patients with a higher misplacement rate were more likely to have screws adjacent to vital organs [adjusted odds ratio: 1.06 (95% confidence interval, 1.01-1.13), P=0.033]. CONCLUSIONS Although only a small number of screws were at risk, they occurred in a large percentage of patients (25%). A single at-risk screw causes a significant complication for the patient. Postoperative imaging beyond routine x-rays may be needed to detect at-risk screws in asymptomatic patients.

Objective Proximal neck dilatation (PND) and/or endograft migration with the subsequent development of type I endoleak is a significant cause of late endograft failure after endovascular abdominal aortic aneurysm repair (EVAR). Although there are numerous reports examining PND in patients receiving endografts that use self-expanding stents (SES) for proximal fixation, there are no such reports for patients treated with endografts that use balloon-expanding stents (BES). The purpose of this study was to investigate PND and endograft migration after EVAR with BES endografts. Methods We retrospectively reviewed all charts and all serial computed tomographic scans available for patients who underwent EVAR with a BES endograft (surgeon-made, aortounifemoral polytetrafluoroethylene graft with a proximal Palmaz stent) between August 1997 and October 2002. Only patients with longer than a 12-month follow-up were analyzed. Neck diameter was measured at the level of the lowest renal artery and at 5 mm below it. PND was defined as neck enlargement of 2.5 mm or more. To assess endograft migration, the distance between the superior mesenteric artery and the cranial end of the BES was measured. Stent migration was defined as a change of 5 mm or more. Results A total of 77 patients received this device during the study period. The technical success rate was 99%. The 1-, 3-, and 5-year survival was 66%, 48%, and 29.5%, respectively. Complete serial computed tomographic scans were available in 41 of the 48 patients who survived 12 months or longer after the operation. The mean follow-up period for these patients was 31 months (range, 12-66 months). The maximum aneurysm diameter was either unchanged or decreased in 35 patients (85%). The immediate postoperative proximal neck diameter was 19 to 29 mm (median, 24 mm). This was unchanged at the latest follow-up. None of the patients had significant PND. The cranial end of the BES was located in the area between 14 mm proximal and 36 mm distal to the superior mesenteric artery (median, 6 mm). None of the patients developed significant endograft migration. Conclusions Neither PND nor endograft migration was observed with the BES endograft. The nature of the SES may be responsible for the observed neck dilatation and device migration after EVAR with SES endografts. This study suggests that BES may be a better fixation method for EVAR.

The clinical significance of type II endoleaks is not well understood. Some evidence, however, indicates that some type II endoleaks might result in aneurysm enlargement and rupture. To identify factors that might contribute to aneurysm expansion, we analyzed the influence of several variables on aneurysm growth in patients with persistent type II endoleaks after endovascular aortic aneurysm repair (EVAR).In a series of 348 EVARs performed during a 10-year period, 32 patients (9.2%) developed type II endoleaks that persisted for more than 6 months. Variables analyzed included those defined by the reporting standards for EVAR (SVS/AAVS) as well as other endoleak characteristics. Univariate, receiver operating characteristic curve, and Cox regression analyses were used to determine the association between variables and aneurysm enlargement.The median follow-up period was 26.5 months (range, 6-88 months). Thirteen patients (41%) had aneurysm enlargement by 5 mm or more (median increase in diameter, 10 mm), whereas 19 (59%) had stable or shrinking aneurysm diameter. Univariate and Cox regression analyses identified the maximum diameter of the endoleak cavity, ie, the size of the nidus as defined on contrast computed tomography scan, as a significant predictor for aneurysm enlargement (relative risk, 1.12; 95% confidence interval, 1.04-1.19; P =.001). The median size of the nidus was 23 mm (range, 13-40 mm) in patients with aneurysm enlargement and 8 mm (range, 5-25 mm) in those without expansion (Mann-Whitney U test, P.001). Moreover, receiver operating characteristic curve and Cox regression analyses showed that a maximum nidus diameter greater than 15 mm was particularly associated with an increased risk of aneurysm enlargement (relative risk, 11.1; 95% confidence interval, 1.4-85.8; P =.02). Other risk factors including gender, smoking history, hypertension, need of anticoagulation, aneurysm diameter, type of endograft used, and number or type of collateral vessels were not significant predictors of aneurysm enlargement.In patients with persistent type II endoleaks after EVAR, the maximum diameter of the endoleak cavity or nidus is an important predictor of aneurysm growth and might indicate the need for more aggressive surveillance as well as earlier treatment.

ObjectivesReduction of length of stay (LOS) is critical for optimal use of hospital resources. We developed and evaluated a system to aggressively reduce LOS for vascular surgery.MethodKey to this system, which we introduced on January 1, 2001, was appointment of a LOS officer, who communicated daily during hospitalization with patients and families about discharge planning, organized outpatient services for wound care and rehabilitation to transition patients quickly to nonhospital care, and had biweekly meetings with relevant paramedical services. LOS for 509 patients operated on in 2000 (standard group) was compared with LOS for 474 operated on in 2001 and 595 patients operated on in 2002 (LOS reduction groups). Data for all patients with aortic aneurysm, carotid artery stenosis, lower extremity critical ischemia or amputation, and foot debridement were included.ResultsLOS in 2000 averaged 8.5 days, compared with 5.9 days in 2001 and 5.6 days in 2002. All decreases in LOS for each diagnostic category in 2001 and 2002 were statistically significant (P = < .001-.03). There was no significant increase in readmission rate (2.2% vs 1.9% and 2.0%, respectively), mortality rate (0.8% vs 0.6% and 0.7%, respectively), or percent of patients who received endovascular treatment (18% vs 16% and 14%, respectively). These decreases in LOS saved the hospital more than $616,200 in 2001, and $847,550 in 2002 ($500/patient-day).ConclusionsA committed LOS officer with major specific daily responsibilities for decreasing LOS and discharging patients resulted in a 31% to 33% decrease in LOS, with important cost savings to the hospital and no negative effect on patient care.

Purpose: To evaluate the patency rates of femorofemoral grafts performed in conjunction with aortomonoiliac or aortomonofemoral (AMI/F) endografts. Methods: Over the past 8 years, 110 patients (98 men; mean age 77 ± 7 years, range 57–90) underwent aortoiliac aneurysm repair with an AMI/F endograft. Follow-up data in these patients were prospectively collected for a mean 2.3 years (range 1–68 months). Results: There were 2 early (Conclusions: Femorofemoral bypasses with AMI/F endografts for aneurysmal disease are durable procedures and have better patency than femorofemoral grafts used to treat occlusive disease. Femorofemoral bypass patency rates alone are not a disadvantage of aortomonoiliac endografts.

Ruptured abdominal aortoiliac aneurysms, when treated with open surgical repair, have high morbidity and mortality rates. Since 1994, the authors have used endovascular approaches to treat this entity. Patients with presumed ruptured aortoiliac aneurysms were treated with restricted fluid resuscitation (hypotensive hemostasis), transport to the operating room, placement under local anesthesia of a brachial or femoral guide wire into the supraceliac aorta, and arteriography. If aortoiliac anatomy was suitable, an endovascular graft (stent-graft) repair was performed. If the anatomy was unfavorable, standard open repair was performed. Only if circulatory collapse occurred was a supraceliac balloon placed and inflated using the previously positioned guidewire. Of 35 patients treated in this manner, 29 underwent endovascular graft repair, and 6 required open repair. Four patients died within 30 days (operative mortality rate, 11%). Only 10 patients required supraceliac balloon control. Endovascular grafts, when combined with hypotensive hemostasis and other endovascular techniques including proximal balloon control, may improve treatment outcomes with ruptured abdominal aortoiliac aneurysms. The authors believe these techniques will become widely used for the treatment of ruptured aneurysms.

Objective: Patients with infrainguinal occlusive disease may experience spontaneous symptomatic improvement. This is generally thought to be from augmented collateral circulation. This study reports another mechanism. Methods: Over a 20-year period, 4123 paients underwent lower extremity arteriography for limb ischemia. For a variety of reasons, 451 patients had repeat arteriography. Results: Five patients were identified as having conclusive arteriographic evidence of spontaneous recanalization of occluded arterial segments without having undergone any surgical or thrombolytic interventions. Repeat contrast arteriography was performed on these patients for failing grafts (n = 2) or contralateral lower extremity ischemia (n = 3). Three other patients had magnetic resonance arteriographic or duplex arteriographic evidence of spontaneous arterial recanalization. Spontaneous recanalizaton occurred in ileofemoral (n = 2), superficial femoral (n = 2), popliteal (n = 3), and peroneal (n = 1) arterial segments. The average time interval of occlusion to recanalization was 21 weeks (2 weeks to 2 years). Two of the eight patients had failed revascularization procedures before spontaneous recanalization. All eight patients had restoration of pulses distal to the recanalized segments and significant symptomatic improvement as defined with the Society for Vascular Surgery/American Association for Vascular Surgery categories for limb ischemia. Conclusion: Spontaneous recanalization of arterial segments can occur and must be considered when evaluating other proposed treatments of critical limb ischemia, including cilostazol, lytic agents, and angiogenic agents, such as vascular endothelial growth factor. Although its true incidence is unknown, this represents another mechanism for spontaneous symptomatic improvement without treatment in patients with severe limb ischemia. (J Vasc Surg 2002;36:1161-6.)

Objective: Carotid artery stenting (CAS) for treatment of carotid stenosis has not received wide acceptance because of the availability of carotid endarterectomy (CEA) with its excellent results and because of the risk of embolic stroke associated with CAS. The feasibility and efficacy of cerebral protection devices that may prevent such embolic complications have yet to be shown. We report our initial results with CAS performed with cerebral protection. Methods: For a period of 28 months, 31 patients with carotid artery stenosis, most of whom were considered at high risk for CEA (87%), underwent treatment with CAS in conjunction with either the PercuSurge GuardWire (n = 19; Medtronic, Minneapolis, Minn), the Cordis Angioguard filter (n = 7; Cordis, Warren, NJ), or the ArteriA Parodi Anti-embolization catheter (n = 4; ArteriA, San Francisco, Calif) with US Food and Drug Administration-approved investigational device exemptions. Factors that made CEA high risk included restenosis after CEA (n = 6), hostile neck (n = 6), high or low lesions (n = 4), and severe comorbid medical conditions (n = 11). Preoperative neurologic symptoms were present in 58%, and the mean stenosis was 85% ± 12%. Data were prospectively recorded and analyzed on an intent-to-treat basis. Neurologic evaluation was performed before and after CAS by a protocol neurologist. Results: CAS was performed with local anesthesia with the Wallstent (n = 23; Boston Scientific Corp, Natick, Mass) or the PRECISE carotid stent (n = 7; Cordis) in conjunction with one of the protection devices in an operating room with a mobile C-arm. Each patient received dual antiplatelet therapy before surgery. The overall technical success rate was 97% (30/31). In one patient, the lesion could not be crossed with a guidewire because of a severely stenosed and tortuous lesion. This patient was not a candidate for CEA and was treated conservatively. In the remaining 30 cases, CAS had a good angiographic result (residual stenosis

Objective: An accepted fact is that abdominal aortic aneurysms (AAAs) larger than 5.5 cm should undergo elective repair. However, subsets of these patients have serious comorbid conditions, which greatly increase operative risk. This study evaluated the outcomes of periods of protracted nonoperative observational management with selective delayed surgery in patients at high risk with large infrarenal and pararenal AAAs. Methods: Among 226 patients with AAAs more than 5.5 cm, we selected 72 with AAAs from 5.6 to 12.0 cm (mean, 7.0 cm) for periods of nonoperative management because of their prohibitive surgical risks. Comorbid factors included a low ejection fraction of 15% to 34% (mean, 22%) in 18 patients, 1 second forced expiratory volume less than 50% (mean, 38%) in 25, prior laparotomy in 10, and morbid obesity in 22. Follow-up examination was complete in the 72 patients for the 6 to 76 months (mean, 23 months) that they underwent nonoperative treatment. Fifty-three patients ultimately underwent operation because of AAA enlargement or onset of symptoms after 6 to 72 months (mean, 19 months) of nonoperative treatment. Results: Of the 72 selected patients, 54 (75%) are living and 18 (25%) are dead. Seven patients who underwent only nonoperative treatment presently survive after 28 to 76 months (mean, 48 months). Of the 18 deaths, AAA rupture occurred in only three patients (4%) who were observed for 12, 31, and 72 months before rupture. Nine other deaths (13%) occurred after 6 to 72 months from comorbidities unrelated to the AAA. Six of the 53 patients who underwent delayed operation died within 30 days of operation (11% mortality rate). The mortality rate for the 154 good-risk patients with an AAA who underwent prompt open or endovascular repair was 2.2%. Conclusion: These data indicate that some patients with large AAAs and serious comorbidities are acceptably managed for long periods (6 to 76 months) with nonoperative means. Substantial delays of 12 to 76 months resulted in an AAA rupture rate of only 4%, and 13% of these patients (nine of 72) died of comorbidities unrelated to AAA rupture or surgery. Mortality rate in this group of patients, when operated, was 11% (six of 53). These findings support the selective use of nonoperative management in some patients with large AAAs and serious comorbidities. (J Vasc Surg 2002;36:41-6.)

Objective: The purpose of this study was to analyze the incidence, severity, and etiologic factors of the development of colon ischemia after endovascular aortoiliac aneurysm repair (EVAR). Methods: During the last 9 years we performed 278 elective EVARs using a variety of grafts. To facilitate these repairs, one hypogastric artery (HA) was coil embolized in 109 patients and both HAs were coil embolized in 13 patients. The preprocedural status of the inferior mesenteric, hypogastric, and iliac arteries as well as anatomical characteristics of the abdominal aortic aneurysm were determined arteriographically and by computerized tomographic scans. Postoperative colon ischemia was documented by colonoscopy or operative findings. Results: Colon ischemia occurred in eight patients (2.9%). Three patients with colon ischemia died and had evidence of widespread (cutaneous, renal, small bowel, and/or lower extremity) microembolization. One of these three had a colectomy and microscopic emboli were present. One other patient who required a colectomy also had pathologic evidence of colonic microembolization but survived. Four other patients with colon ischemia were treated conservatively and survived. In one patient, previous colectomy with interruption of mesenteric collaterals may have been a contributory cause of colon ischemia. Of the eight patients with colon ischemia, only one had unilateral HA occlusion, and none had bilateral HA occlusion. The other 121 patients with unilateral and bilateral HA occlusion had no evidence of colon ischemia. Conclusions: Colon ischemia occurs after EVAR with an incidence approximating that of open repair. Colon ischemia was unrelated to HA interruption. Embolization appears to be a major cause of colon ischemia, although inadequate mesenteric collateral circulation may also play an etiologic role. Mortality with colon ischemia accompanied by widespread embolization was high, whereas colon ischemia without it was often mild and amenable to nonoperative management. (J Vasc Surg 2001;34:986-96.)

Purpose: Arteriography is the diagnostic test of choice before lower extremity revascularization, because it is a means of pinpointing stenotic or occluded arteries and defining optimal sites for the origin and termination of bypass grafts. We evaluated whether a duplex ultrasound scan, used as an alternative to arteriography, could be used as a means of accurately predicting the proximal and distal anastomotic sites in patients requiring peripheral bypass grafts and, therefore, replace standard preoperative arteriography. Methods: Forty-one patients who required infrainguinal bypass grafts underwent preoperative duplex arterial mapping (DAM). Based on these studies, an observer blinded to the operation performed predicted what operation the patient required and the best site for the proximal and distal anastomoses. These predictions were compared with the actual anastomotic sites chosen by the surgeon. Results: Whether a femoropopliteal or an infrapopliteal bypass graft was required was predicted correctly by means of DAM in 37 patients (90%). In addition, both anastomotic sites in 18 of 20 patients (90%) who had femoropopliteal bypass grafts and 5 of 21 patients (24%) who had infrapopliteal procedures were correctly predicted by means of DAM. Conclusion: DAM is a reliable means of predicting whether patients will require femoropopliteal or infrapopliteal bypass grafts, and, when a patient requires a femoropopliteal bypass graft, the actual location of both anastomoses can also be accurately predicted. Therefore, DAM appears able to replace conventional preoperative arteriography in most patients found to require femoropopliteal reconstruction. Patients who are predicted by means of DAM to require crural or pedal bypass grafts should still undergo preoperative contrast studies to confirm these results and to more precisely locate the anastomotic sites. (J Vasc Surg 1999;29:100-9.)

Purpose: Anatomic features, such as a high carotid bifurcation (2.0 cm above the carotid bifurcation), or a small diameter (≤0.5 cm) redundant or kinked internal carotid artery can complicate carotid endarterectomy. In the past, arteriography was the only preoperative study capable of imaging these features. This study assessed the ability of duplex ultrasound to evaluate their presence before surgery. Methods: A consecutive series of 20 patients who underwent 21 carotid endarterectomies had preoperative duplex ultrasound evaluations of these anatomic features. These evaluations were correlated with operative measurements from an observer blinded to the duplex findings. Results: The mean difference between duplex and operative measurements for the distance between the carotid bifurcation and the angle of the mandible, the distal extent of plaque, and the internal carotid artery diameter was 0.9 cm, 0.3 cm, and 0.8 mm, respectively. The correlation coefficient between the two methods was 0.86, 0.75, and 0.59, respectively. Duplex ultrasound predicted a high carotid bifurcation, excessive distal extent of plaque, or a redundant or kinked internal carotid artery with 100% sensitivity (p < 0.05, p < 0.01, and p < 0.001, respectively). The sensitivity of duplex ultrasound in predicting a small internal carotid artery diameter was 80%. The specificity of duplex ultrasound for predicting excessive distal extent of plaque, small internal carotid artery diameter, high carotid bifurcation, and a coiled or kinked carotid artery was 92%, 56%, 100%, and 100%, respectively. Conclusions: Duplex ultrasound can predict the presence of anatomic features that may complicate carotid endarterectomy. Preoperative duplex imaging of these features may be helpful in patients who undergo carotid endarterectomy without preoperative arteriography. (J Vasc Surg 1998;27:235-44.)

Purpose: There are excellent arguments in favor of the preferential use of prosthetic grafts above the knee for the treatment of infrainguinal occlusive disease. This approach has been popularized on the basis of the seemingly acceptable results when using polytetrafluoroethylene (PTFE). However, in many centers, knitted Dacron polyester has been used in these patients, and there are several studies that show equivalent and, in some, superior results with Dacron when compared with PTFE. The purpose of this study was to examine these results in a definitive way. Methods: A randomized prospective trial in eight clinical academic centers in the United States and Canada was initiated in 1991. Two hundred forty-four patients eligible for such a study, by virtue of criteria extant in each institution at the time, were centrally randomized. They underwent placement of either a knitted Dacron polyester graft impregnated with collagen or a thin-wall expanded reenforced PTFE graft to the above-knee popliteal artery, usually from the common femoral artery. They were frequently observed by protocol for as long as 5 years by a physical examination noninvasive hemodynamic study, including duplex scanning in many instances. Continuing patency was noted, as were other potential adverse outcome events. The data were analyzed by the log-rank test for cumulative patency and expressed as Kaplan-Meier curves. Data were further analyzed with a Cox proportional hazards model. Results: There were no differences in graft groups in demographic or comorbid factors. The procedural mortality rate was zero, and the morbidity rate was low (6.5%). The long-term patient survival rate was excellent (77% at 3 years). At the end of these years, no statistical significance in primary or secondary patency rates was observed between the two grafts (primary patency rate, 62% ± 14.4% for Dacron; 57% ± 15.5% for PTFE). No unexpected adverse outcomes on limb status were noted. Patency rates in both graft groups were inferior in patients who received small grafts (5 to 6 mm vs 7 to 8 mm; hazards ratio, 4.15) and younger (

Introduction: The causes and management of prosthetic graft infections have been extensively studied for conventional bypass grafts; however, the infectivity and therapy for endovascular graft infections are completely unknown. The aim of this study was to compare the biologic properties of infected aortic grafts when inserted by endoluminal or standard transabdominal techniques. Methods: Eighteen dogs underwent placement of polytetrafluoroethylene grafts in their infrarenal aortas either by an endovascular technique (8) or a standard interposition technique (10). Endovascular grafts were constructed from polytetrafluoroethylene (3 cm) and two balloon-expandable stents coaxially mounted onto a balloon catheter delivery system. The grafts were inserted through a left carotid arteriotomy under fluoroscopic control. Initially, seven grafts were infected with decreasing inocula of Staphylococcus aureus, starting at 10 7 organisms per ml for 30 minutes and then rinsed briefly (10 seconds) in normal saline solution, until a 50% infective dose for the standard grafts was determined to be 10 2 organisms per ml. After this initial experiment, a second group of 11 dogs were compared at a concentration of 10 2 S. aureus per ml. Five dogs underwent endovascular repair, and six dogs had standard graft interpositions after an identical period of bacterial exposure. All grafts were removed at 2 weeks under sterile conditions and were submitted for quantitative culture analysis. Results: Three of the six dogs (50%) with standard grafts appeared to clear their infections, whereas only one of the five dogs (20%) with an endovascular graft was free of organisms at 14 days. This result was further manifested by statistically significant lower postmortem colony counts in the standard grafts ( p Conclusions: The endoluminal position of the graft and its proximity to the arterial wall do not appear to provide protection against infection. These data suggest that if endovascular grafts become infected, they may be in a disadvantaged position for host defense mechanisms to be effective. (J Vasc Surg 1996;24;920-6.)

Purpose: Vein graft stenosis caused by intimal hyperplasia (IH) accounts for 30% to 50% of late bypass graft failures; however, the biochemical mediators of vein graft IH have been poorly defined. We attempted to evaluate the spatial and temporal distribution of five principal cytokines (interleukin-1 beta [IL-1β], platelet-derived growth factor AA [PDGF-AA], basic fibroblast growth factor [bFGF], interferon gamma [INFγ], and tumor necrosis factor alpha [TNF-α]) during the development of IH in a rat vein graft model. Methods: Rat epigastric vein interposition grafts in the femoral artery were harvested at 6 hours, 2 days, 1 week, 2 weeks, and 4 weeks after the grafting procedure and studied with immunohistochemical and standard histologic techniques. The cytokine expression in the endothelium and media/neointima was quantified as the percentage of immunopositive cells per high-power field. Results: Maximal hyperplasia occurred 2 weeks after the grafting procedure. Peak expression of IL-1β and bFGF occurred by 2 days. PDGF-AA expression paralleled the development of IH, peaking at 2 weeks and then declining. TNF-α expression increased at 1 week and remained elevated. INFγ was seen only in control grafts. Conclusions: The coordinated early release of IL-1β and bFGF and the down-regulation of INFγ seem to trigger an inflammatory response, thereby initiating IH. The process then is propagated by the release of PDGF-AA and TNF-α, with concomitant smooth muscle cell proliferation and production of extracellular matrix. It is likely that this complex milieu of local paracrine signaling is required to generate the hyperplastic response seen in failing vein grafts. (J Vasc Surg 1996;24:463-71.)

Purpose The occurrence of neointimal hyperplasia within a stent may result in restenosis with recurrent symptoms of end-organ ischemia. This study evaluated the potential of a nonporous covering of a stent to function as a barrier to the formation of intrastent neointimal hyperplasia. Materials and Methods Twelve endovascular stent grafts were used to treat 12 high-risk patients with limb-threatening ischemia secondary to long-segment iliac artery occlusion. A 6-mm, thin-walled polytetrafluoroethylene graft was inserted and anchored to the common iliac artery with use of Palmaz stents. Each stent was covered by graft material over one-half of its length. Control angiograms obtained immediately after graft insertion were compared with follow-up angiograms obtained between 4 and 6 months after the initial procedure. On each angiogram, the region of the stent was magnified by 20x to permit computerized luminal diameter measurements. Results The mean luminal diameter within the stent was significantly greater on the covered (7.7mm ± 0.33 standard deviation) compared with the uncovered (6.7mm ± 0.85 standard deviation) portions ( P Conclusions Partially covered stents are a unique model for assessing the effects of an extrinsic stent covering on arterial healing and myointimal hyperplasia. These data suggest that a relatively nonporous covering of polytetrafluoroethylene may inhibit stent-related restenosis in iliac arteries.

We performed bilateral femoral artery dissections in a single 50 kg mongrel dog. Digital fluoroscopic arteriograms documented the luminal diameter of the left iliac and right superficial femoral arteries. Balloon thrombectomy catheter passage was performed through hemostatic sheaths by 12 surgeons. Embolectomy balloons were filled with radiographic contrast material and the balloon catheter diameter was compared with the underlying vessel diameter. The percentage of overdistention of the embolectomy balloon relative to the arterial wall was 23% +/- 5% in the iliac artery and 40% +/- 13% in the femoral artery. Over a 25-month period, we used fluoroscopically assisted thromboembolectomy to treat 21 patients with acute arterial or graft occlusions. As the balloon was gently withdrawn to extract intravascular thrombus, deformities of the compliant balloon profile caused by underlying arterial lesions were identified fluoroscopically and their locations recorded to facilitate further treatment. After initial clot removal in these 21 patients, 15 residual lesions were documented. Repeat thrombectomy (n = 8), balloon angioplasty (n = 3), and placement of intravascular stents (n = 4) eliminated all 15 lesions. Luminal continuity was successfully restored in all 21 of these patients, 10 of whom required distal open vascular reconstruction to correct existing outflow artery disease. Fluoroscopically assisted thromboembolectomy is a simple and safe method for treating acute arterial or graft occlusions in patients with diffuse arteriosclerosis. It minimizes arterial damage and blood loss during balloon thrombectomy and reduces the need for intravascular contrast agents. It also has the potential to facilitate accurate identification, localization, and treatment of significant underlying arterial lesions.

Purpose: This study was undertaken to evaluate our results of polytetrafluoroethylene (PTFE) tibial and peroneal artery bypasses done for limb salvage. Methods: Within a group of patients undergoing infrainguinal limb salvage bypasses at our institution between January 1986 and May 1995, 63 patients faced an immediate amputation, had no autologous vein on duplex examination and operative exploration, and had only a tibial or peroneal artery as an outflow vessel for bypass. Most of these patients (82%) had two or more prior ipsilateral infrainguinal bypasses. These 63 patients underwent 66 PTFE bypasses to a tibial or peroneal artery without a distal anastomotic vein cuff or an adjunctive arteriovenous fistula. Our results were then compared with those reported from infrapopliteal (crural) bypasses performed with alternate autologous vein sources or PTFE in conjunction with various recommended adjuncts. Results: The 3- and 5-year cumulative primary graft patency rates for our PTFE infrapopliteal bypasses were 39% ± 7% and 28% ± 9%, respectively. Secondary graft patency rates were 55% ± 8% and 43% ± 10% at 3 and 5 years, respectively. Limb salvage rates were 71% ± 7% at 3 years and 66% ± 8% at 5 years. Two-year actuarial patient survival rate was only 67% ± 7%. Conclusions: These results indicate that a PTFE bypass to an infrapopliteal artery remains a worthwhile option in patients without usable autologous vein. The secondary patency and limb salvage rates were acceptable in this setting and were not significantly different from the best results reported with prosthetic tibial/peroneal bypasses with distal vein cuffs or patches (74% at 1 year; 58% at 3 years), arteriovenous fistulas (71% at 1 year) or composite arm vein grafts (39% and 29% at 3 and 5 years, respectively). (J VASC SURG 1996;23:347-56.)

Purpose: The purpose of this study was to perform a preliminary histopathologic analysis of explanted human endovascular stented grafts from patients treated for occlusive disease. Methods: Over a 16-month period, 26 endovascular stented grafts were placed in 21 patients with limb-threatening ischemia caused by aortoiliac or femoral artery occlusive disease. All grafts were inserted through open arteriotomies remote from the region of primary disease. During the follow-up period, two patients died of preexisting heart disease 2 weeks and 7 months after grafting, and a portion of their endovascular grafts with the surrounding artery was explanted. Specimens from five other endovascular grafts were obtained during surgical revision for graft stenosis after 3 and 6 weeks and for outflow artery stenosis after 3, 5, and 6 months. All specimens were formalin fixed and studied with hematoxylin and eosin and trichrome staining and immunohistochemically for factor VIII–related antigen, alpha actin smooth muscle, macrophage antigen (MAC-387) and PC-10 (a mouse monoclonal antibody which specifically recognizes proliferating cell nuclear antigen in paraffin sections). Results: Three weeks after placement of the stented grafts, organizing thrombus was present on both surfaces of the expanded polytetrafluoroethylene (PTFE) grafts. At 6 weeks, evidence of a neointima with overlying endothelium was seen in the perianastomotic region, and 3 months after grafting it was seen 1 to 3 cm from the anastomosis. The specimen explanted at 5 months demonstrated factor VIII–positive cells 8 cm from the anastomosis. The histopathologic condition of the external capsule appeared to vary, depending on the presence or absence of an external wrap on the PTFE graft and on which layer in the arterial wall the graft was inserted. A foreign body reaction characterized by multinucleated giant cells was seen adjacent to wrapped grafts or around those placed in an intraadventitial plane. Grafts inserted within the media were surrounded by orderly, arranged, smooth muscle cells and few mononuclear cells. Extensive smooth muscle cell proliferation (PC-10 activity) was not seen within native artery atherosclerotic plaques peripherally displaced and external to prosthetic endovascular grafts. Conclusions: These preliminary observations on the healing of PTFE endovascular stented grafts in human beings demonstrate limited plaque hyperplasia and the presence of endothelial cells on the luminal surface remote from the graft-artery anastomosis. It is unclear whether this is a unique manifestation of healing in prosthetic grafts inserted within the walls of arteries. (J VASC SURG 1995;21:595-604.)

background : Endovascular stented grafts employ a new technique that blends intravascular stent and prosthetic graft technologies. These devices may be used to treat arterial aneurysms, occlusive disease, and vascular injuries. This report describes the application of stented grafts to the treatment of limb-threatening ischemia secondary to occlusive disease of the aorta, iliac, and femoral arteries. methods : Three patients with limb-threatening ischemia and severe comorbid medical illnesses were treated with transvascular stented grafts that were composed of 6-mm thin-walled polytetrafluoroethylene grafts and Palmaz balloon expandable stents. The grafts were inserted through a cutdown in an artery remote from the site of occlusion and introduced into the vascular system within 14-Fr introducer sheaths. results : Technical success was documented in all three patients with restoration of arterial continuity following stent graft deployment. Patency and limb salvage has been achieved to 1 year. One patient required further dilatation of the proximal stent at 6 weeks. Complications were limited to an iliofemoral deep vein thrombosis in one patient. conclusions : Endovascular stented grafts can be inserted to treat limb-threatening ischemia. Although these initial results are encouraging, greater experience in more patients observed for longer periods of time is necessary before this technique can be advocated for widespread use.

Purpose: The purpose of this study was to review the 91 failing polytetrafluoroethylene (PTFE) grafts that were treated at our institution over the past 12 years to better understand their cause and improve the diagnosis and treatment of these grafts. Methods: Eighty-five patients with 91 failing grafts were retrospectively reviewed. The 144 graft-threatening lesions associated with these grafts were characterized by location (inflow artery, outflow artery, anastomosis, or graft body) and treatment method used (surgery, balloon angioplasty, or thrombolysis). Results: Progression of atherosclerotic disease was the predominant cause of failing PTFE grafts with 43 inflow lesions and 83 outflow lesions, accounting for 87% of all lesions identified. Ten lesions (7%) were noted within the prosthetic grafts, whereas only eight (6%) lesions were noted at the anastomoses. Forty stenotic lesions 2 cm in length or less were treated with percutaneous transluminal balloon angioplasty, whereas 100 lesions were treated by patch angioplasty or graft extensions. The remaining four lesions, present within the prosthetic grafts, were treated with thrombolytic therapy. The 5-year cumulative patency rate for all failing PTFE grafts was 71%, whereas that of failing femoropopliteal PTFE grafts was 64%. The 5-year limb salvage rate for all failing PTFE grafts was 73%. Conclusions: The progression of inflow and outflow disease is the predominant cause of failing PTFE grafts, which suggests that this process is a more important cause of PTFE graft thrombosis than is generally recognized. Frequent PTFE graft surveillance may permit detection of some threatening lesions before graft thrombosis occurs and may help maintain and prolong graft patency. The enhanced 5-year patency and limb salvage rates for treated failing PTFE grafts compared with the known poor outcome after reinterventions for PTFE graft failure support the conclusion that surveillance of PTFE grafts is worthwhile. (J VASC SURG 1993;18:981-90.)

Purpose: The purpose of this study was to retrospectively evaluate the effectiveness of screening for coronary artery disease before elective repair of abdominal aortic aneurysms (AAA) was performed. Methods: Results of a screening algorithm for coronary artery disease in 263 patients admitted to a single hospital for elective repair of AAA between January 1986 and December 1989 were analyzed. Patients with no coronary artery disease indicators proceeded to surgery without further workup. Patients with cardiac disease indicators underwent dipyridamole-thallium scintigraphy, and patients with angina were screened by use of cardiac catheterization; those with a recent coronary revascularization underwent no additional screening unless symptoms or electrocardiographic changes suggested an intervening event. Twenty-eight patients underwent no screen other than medical history and electrocardiogram. Results: Among 164 patients screened with dipyridamole-thallium scintigraphy, 44 patients had redistribution defects that required catheterization, and 11 of these underwent coronary revascularization. Cardiac catheterization was performed directly in 42 patients, which led to 11 revascularizations before AAA repair. Previous coronary artery bypass or percutaneous transluminal angioplasty obviated additional screening in 29 patients. Of the 263 scheduled AAA repairs, 15 were cancelled because of unacceptable operative risks, 13 for cardiac reasons. One patient died of a ruptured AAA after an uneventful coronary artery bypass. Among the 247 AAA repairs performed, there were three perioperative deaths (1.2%), all of which resulted from sudden cardiac events; three additional patients had nonfatal myocardial infarctions (1.2%), for a total cardiac complication rate of 2.4%. Conclusions: The low rate of cardiac complications in this experience affirms the effectiveness of preoperative screening and selective coronary revascularization before AAA repair. (J VASC SURG 1993;18:349-57.)

Obesity independently increases the risk of pulmonary embolism (PE). We compare a superobese population (body mass index [BMI]55 kg/m(2)) undergoing open gastric bypasses (OGBs) with a similarly matched group of laparoscopic gastric bypasses (LGB) to see if the incidence of PE differs. We included all patients undergoing OGB (n = 193, average BMI = 51 kg/m(2)) at our institution by a single surgeon between July 1999 and April 2001. Thirty-one patients were superobese (BMI55 kg/m(2)). LGB was started at our institution in April 2001. Since that time 213 patients (average BMI = 52 kg/m(2)) have undergone the procedure. One hundred and nine patients were superobese. Pre- and postoperative prophylaxis included sequential compression stockings and subcutaneous heparin. Postoperatively, patients who developed signs of hypoxia, tachypnea, or tachycardia underwent a chest X-ray and spiral computed tomography. In addition, all patients who expired in the 30-day postoperative period underwent postmortem examination. Data were analyzed using the chi-squared test. In the OGB group, four patients (2.1%) developed PE. All occurred in superobese patients with a BMI55 kg/m(2). Three were fatal PEs and one was nonfatal. None of these patients had a prior history of deep vein thrombosis, PE, venous stasis disease, or pulmonary hypertension. In the LGB group, one patient (0.9%) had a nonfatal PE. This patient had a history of deep vein thrombosis. The incidence of PE was statistically higher in the superobese OGB group (P0.01). Despite the theoretical hindrance to venous return and vena caval compression observed with pneumoperitoneum, fewer PEs occurred in the laparoscopic group. Our data, however, suggest that patients with a BMI55 kg/m(2) might be at an increased risk for PE independent of operative approach.

During a period of nine years, 10 patients, ages 42 to 66 years (55 +/- 7, mean +/- SD) underwent upper extremity bypass for ischemic changes to the hand not responsive to conservative management. Patients were referred from the vascular department at the authors' institution. Preoperative angiograms were performed and attempts at angioplasty or intravenous attempts to dissolve clots were carried out (with tissue plasminogen activator-tPA) when appropriate. Patients with persistent upper extremity ischemia and an obvious occlusion with reconstitution in the hand were candidates for upper extremity bypass to the palmar arch. All patients had upper extremity bypasses performed with reverse saphenous vein grafts. The proximal anastomoses (end-to-side) were performed by either the vascular or plastic surgery team, while all distal anastomoses (end-to-side) were performed by plastic surgery team microscopic magnification to the deep or superficial palmar arch. Postoperative follow-up ranged from 3 months to 3 years. The bypass graft to the hand resulted in improved pain and resolution of tissue ischemia in all cases. Patients with preoperative ulcers were completely healed by 3 months. The results are in accordance with previous studies demonstrating that improved blood flow afforded by the procedure can improve the healing of recalcitrant ulcers and mitigate the symptoms of ischemic changes. In addition, end-to-side anastomosis to the palmar arch offers significant advantages, in that the continuity of the arch is maintained with all possible outflow vessels, and the problems associated with size discrepancy in the anastomosed vessels are eliminated.

Objectives The purpose of this study was to review our experience with delayed open conversion (>30 days) following endovascular aortoiliac aneurysm repair (EVAR) and to introduce the concept and advantages of endograft retention in this setting. Methods From January 1992 to January 2003, a total of 386 EVARs using a variety of endografts were successfully deployed. Eleven (2.8%) patients required delayed conversion to open repair at an average of 30 months (range, 10-64). Data from all patients undergoing both EVAR and open conversion were prospectively collected. Results EVARs were performed using grafts made by Talent (4), Vanguard (2,) AneuRx (1), and Surgeon (4). Conversion to open repair (9 transabdominal, 1 retroperitoneal, 1 transabdominal plus thoracotomy) was performed for aneurysm rupture in 7 patients (4 type 1 endoleak, 2 type 2 endoleak, 1 aortoenteric fistula) and aneurysm enlargement in 4 patients (1 type 1 endoleak, 1 type 2 endoleak, 1 type 3 endoleak, 1 endotension). Patients with aneurysm rupture were treated on an emergent basis. Complete removal of the endograft with supraceliac cross-clamping was performed in two cases. One patient (rupture) did not survive the operation, and one patient (aortoenteric fistula) died 2 weeks postoperatively. In the remaining nine cases, the endograft was either completely (1) or partially (6) removed, or left in situ (2). Supraceliac balloon control (2), supraceliac clamping (1), suprarenal clamping (1), or infrarenal clamping (5) was used in these cases. All nine of these patients survived the operation. In one procedure in which the endograft was left intact (endotension), repair was accomplished by exposing the endograft and by placing a standard tube graft over it as a sleeve. In the second procedure in which the graft was left in situ (rupture), the graft was well incorporated, and bleeding lumbar arteries were oversewn and the sac was closed tightly over the endograft. In the remaining 7 cases, the endograft was transected and the proximal portion only (6) or the proximal and distal portions (1) were excised. All surviving patients continue to do well and remain without complications associated with the endograft remnant at a mean follow-up of 22 months (range, 3-56) from the time of open conversion and 46 months (range, 10-73) from the time of original EVAR. Conclusions Open repair in the setting of a long-standing endograft offers several unique technical challenges but can be successfully accomplished in most patients. Preservation of all or part of the endograft is possible in many patients. This technique simplifies the operative approach and is preferred over complete endograft removal if possible.

Objective: Precise diameter changes in iliac artery aneurysms (IAAs) after endovascular graft (EVG) repair are yet to be determined. This report describes the midterm size changes in isolated IAAs 13 to 72 months after treatment with an EVG. Methods: From January 1993 to April 1999, 31 patients with 35 true isolated IAAs (32 common iliac and 3 hypogastric) had these lesions treated with EVGs and coil embolization of the hypogastric artery or its branches. The EVG used in this study consisted of a balloon-expandable stent attached to a polytetrafluoroethylene graft. Contrast-enhanced spiral computed tomographic scans were performed at 3- to 6-month intervals to follow the aneurysms for change in diameter and endoleaks. Results: Thirty patients had a decrease in the size of their iliac aneurysms with EVG repair. All EVGs remained patent. All patients, except for one, were followed up for 13 to 72 months (mean, 31 months). The pretreatment aneurysm size ranged from 2.5 to 11.0 cm in diameter (mean, 4.6 ± 1.62 cm). After EVG treatment, the aneurysms ranged from 2.0 to 8.0 cm in diameter (mean, 3.8 ± 1.36 cm). The change in aneurysm diameter ranged from 0.5 to 3.1 cm (mean, 1.1 ± 0.62 cm) with an average change of –0.516 ± 0.01 cm/y for the first year. Five patients died of their intercurrent medical conditions during the follow-up period. One of the patients had a new endoleak and an increase in common iliac aneurysm size 18 months after EVG treatment, despite an early contrast-enhanced computed tomographic scan that showed no endoleak. This patient's aneurysm ruptured, and a standard open surgical repair was successfully performed. Another patient had a decrease in hypogastric aneurysm size after EVG treatment and no radiographic evidence of an endoleak, but eventually the aneurysm ruptured. He was successfully treated with a standard open surgical repair. Conclusions: EVGs can be an effective treatment for isolated IAAs. Properly treated with EVGs, IAAs decrease in size. The enlargement of an IAA, even if no endoleak can be detected, appears to be an ominous sign suggestive of an impending rupture. IAAs that enlarge should be closely evaluated for an endoleak. If an endoleak is detected, it should be eliminated if possible. If an endoleak cannot be found, open surgical repair should be considered. (J Vasc Surg 2001;33:289-95.)

A bilayered tissue-engineered skin graft composed of human neonatal foreskin fibroblasts and keratinocytes in a type I bovine collagen matrix has been developed. We sought to determine if this graft improves wound healing after lower extremity revascularization. Thirty-one previously ischemic foot wounds were randomly assigned to moist dressing changes or tissue-engineered skin graft within 60 days of revascularization. In the grafted group, 10 received meshed and 11 received unmeshed graft. Wound healing was followed by wound area measurements and photography. There were no statistically significant differences between groups in patient age, sex, diabetes or renal failure risk factors, revascularization procedure, or wound location or size. Treatment with tissue-engineered skin graft was significantly more effective than moist dressing in the percentage of wounds healed (62 vs. 0% at 8 weeks, 86 vs. 40% at 12 weeks, p0.01) and the median time to complete wound closure (7 vs. 15 weeks, p = 0.0021, rank-sum test). There was no difference in the wound closure rate of meshed and unmeshed graft at 4, 8, 12, or 24 weeks (p0.05). Three indolent localized wound infections in the tissue-engineered skin graft group were the only complication. Tissue-engineered skin grafting can be used safely in previously ischemic wounds after lower extremity revascularization. Treatment with this graft promotes healing more rapidly and in more patients than standard moist dressings. It obviates the risk, inconvenience, and expense of donor skin harvesting, anesthesia, and hospitalization associated with autologous skin grafting. This graft may represent an advance in the treatment of previously ischemic lower extremity foot wounds.

Background: Intra-arterial thrombolytic therapy is currently a therapeutic option for the treatment of acute limb ischemia. A recent large prospective randomized trial (TOPAS) comparing lytic therapy and operative intervention showed that both forms of treatment had similar results in terms of amputation-free survival. However, the exact role for lytic treatment is unclear. Method: Over a 4-year period we treated 60 cases of acute limb ischemia in 57 patients secondary to native artery occlusion with thrombolytic therapy with urokinase. All patients were evaluated at 1 week, 1 month, and then at 3-month intervals posttreatment. Follow-up evaluations included pulse examination, pulse volume recordings, and duplex examinations to confirm arterial patency. No patients were lost to follow-up with a range of 8 to 54 months (mean 26). Results: Of these 60 native arterial occlusions, complete lysis was achieved in 46 cases (76%). Of these 46 cases, 18 required lysis only, 19 cases (9 iliac, 7 superficial femoral artery (SFA), and 3 popliteal) required angioplasty of lesions uncovered by clot lysis, and 9 patients had lysis and angioplasty of iliac arteries followed by infrainguinal bypasses. Eight of the 57 patients (14%) who had been asymptomatic presented with symptoms limited to new onset claudication, all of which were successfully lysed. Cumulative patency for the 43 successful cases was 90% ± 5% at 1 year and 75% ± 4% at 2 years. The 1-year amputation-free survival for all native artery occlusions was 85% ± 6%. Conclusion: Thrombolysis with urokinase simplified the treatment of native arterial occlusion proving to be the sole therapy in 18 (29%) patients or a valuable adjunct by facilitating the angioplasty of arterial lesions and avoiding open surgery in 60% of patients treated. In addition, the correction of inflow lesions reduced the magnitude of required subsequent bypass procedures to achieve limb salvage. In conclusion, successful thrombolysis of native artery occlusion provided durable arterial patency and limb salvage, particularly in patients with new onset claudication.

To analyze the authors' midterm results (up to 4 years) using endovascular grafts to treat aortoiliac occlusive disease in patients with limb-threatening ischemia.Endovascular grafts are being used to manage some aortoiliac lesions formerly treated by aortofemoral or extraanatomic bypass grafts. However, widespread acceptance of these new grafts depends on their late patency and clinical utility.Between January 1993 and December 1997, 52 patients with aortoiliac occlusive disease were treated with endovascular grafts. The primary indication for treatment was gangrene or ulceration in 42 patients (81%) and rest pain in 10 patients (19%). Sixteen patients had symptomatic contralateral limbs that were also treated, and 27 (52%) patients required a synchronous infrainguinal bypass. Results up to 4 years were evaluated by life table analysis.Forty-six (88%) of the patients had complete follow-up of 3 to 57 months (median 22 months). Six patients were lost to follow-up at a mean of 20 months after surgery. The 4-year primary and secondary patency rates for the endovascular grafts were 66.1% and 72.3% respectively. Six patients required a major amputation, and the limb salvage rate was 88.7%. Four-year patient survival was 37%, with 23 patients dying during this follow-up period.Endovascular grafts can often be used when conventional procedures are contraindicated or technically impractical. These grafts are a valuable alternative to extraanatomic and aortofemoral bypasses in high-risk patients with aortoiliac occlusive disease and critical ischemia.

Purpose: To develop an ex vivo human carotid artery stenting model that can be used for the quantitative analysis of risk for embolization associated with balloon angioplasty and stenting and to correlate this risk with lesion characteristics to define lesions suitable for balloon angioplasty and stenting. Methods: Specimens of carotid plaque (n = 24) were obtained circumferentially intact from patients undergoing standard carotid endarterectomy. Carotid lesions were prospectively characterized on the basis of angiographic and duplex findings before endarterectomy and clinical findings. Specimens were encased in a polytetrafluoroethylene wrap and mounted in a flow chamber that allowed access for endovascular procedures and observations. Balloon angioplasty and stenting were performed under fluoroscopic guidance with either a Palmaz stent or a Wallstent endoprosthesis. Ex vivo angiograms were obtained before and after intervention. Effluent from each specimen was filtered for released embolic particles, which were microscopically examined, counted, and correlated with various plaque characteristics by means of multivariate analysis. Results: Balloon angioplasty and stenting produced embolic particles that consisted of atherosclerotic debris, organized thrombus, and calcified material. The number of embolic particles detected after balloon angioplasty and stenting was not related to preoperative symptoms, sex, plaque ulceration or calcification, or artery size. However, echolucent plaques generated a higher number of particles compared with echogenic plaques (p < 0.01). In addition, increased lesion stenosis also significantly correlated with the total number of particles produced by balloon angioplasty and stenting (r = 0.55). Multivariate analysis revealed that these two characteristics were independent risk factors. Conclusions: Echolucent plaques and plaques with stenosis ≥90% produced a higher number of embolic particles and therefore may be less suitable for balloon angioplasty and stenting. This ex vivo model can be used to identify high-risk lesions for balloon angioplasty and stenting and can aid in the evaluation of new devices being considered for carotid balloon angioplasty and stenting. (J Vasc Surg 1998; 27:463-71)

Occlusive disease of the aorta and iliac and femoral arteries may lead to limb-threatening ischemia when multiple levels of disease are present. The combined treatment of severe aortoiliac and infrainguinal disease using standard techniques may be hazardous or contraindicated in patients with multiple, previous reconstructions or severe co-morbid medical illnesses. This report summarizes the technical feasibility and early results of aortoiliac endovascular stented grafts (ESGs) in combination with conventional surgical reconstructions for the treatment of multilevel arterial occlusive disease. Forty-two patients with multilevel aortoiliofemoral limb-threatening occlusive disease had an ESG inserted to treat long-segment, multilevel, occlusive disease. ESGs originated from either the aorta or the common iliac artery and were inserted into one of the femoral arteries. ESG lengths ranged from 16 to 30 cm (mean 21 cm). Conventional surgical bypasses were constructed, when necessary, from polytetrafluoroethylene (PTFE) or saphenous vein and were extended using standard techniques to the popliteal, tibial, or contralateral femoral arteries. Technical success of graft insertion was achieved in 39 of 42 attempted ESG procedures (93%). The 18-month primary and secondary cumulative patency rates for ESGs were 89 +/- 9 (SE) and 100%, respectively. Limb salvage was achieved in 94% of patients at 24 months. Four patients had minor postprocedure complications (10%), and there was one death. Endovascular aortoiliac grafts, often in combination with conventional surgical infrainguinal bypasses, are a technically feasible, potentially safe option for the treatment of limb-threatening aortoiliofemoral occlusive disease and have demonstrated encouraging early patency. Long-term follow-up is necessary before widespread application of this technique is instituted.

Controversy exists over the value of intraoperative monitoring and shunting in patients undergoing carotid endarterectomy. Although it is widely believed that contralateral carotid occlusion and previous stroke mandate intraoperative shunting, the susceptibility of these two groups of patients to cerebral ischemia during carotid artery endarterectomy is not well defined. Somatosensory evoked potentials (SSEPs) were monitored in 113 carotid artery endarterectomy patients. Of these, 32 (28.3%) had a previous stroke, 24 (21.2%) had a contralateral carotid occlusion and 33 (29.2%) were diabetic. There were no deaths and only one perioperative stroke (0.9%). Cerebral ischemia occurred in 14 patients (12.4%). Six of these patients had a contralateral carotid occlusion. Some 29 patients (25.7%) were shunted, including 10 with contralateral carotid occlusions that did not have major SSEP changes. In the latter half of the study, 14 patients with contralateral carotid occlusions were selectively shunted (six shunted, eight not shunted) with no neurological complications. Thirty-two patients with prior strokes were selectively shunted (nine shunted, 23 not shunted); of these, one shunted patient undergoing combined carotid artery endarterectomy and coronary artery bypass grafting had a perioperative stroke. Intraoperative monitoring with SSEPs accurately identifies cerebral ischemia secondary to carotid clamping as well as patients requiring shunts. With use of intraoperative SSEP monitoring, selective shunting may be safely performed in patients with a contralateral carotid occlusion or a previous stroke.

Purpose: Intravascular stents have become important tools for the management of vascular lesions; however, stents in combination with vascular grafts have only recently reached clinical application. This report describes an experience with stented grafts for the treatment of penetrating arterial trauma. Methods: Seven transluminally placed stented grafts were used to treat one arteriovenous fistula and six pseudoaneurysms. These grafts were successfully inserted percutaneously or through open arteriotomies that were remote from the site of vascular trauma. The devices were composed of balloon-expandable stainless steel stents covered with polytetrafluoroethylene grafts. Results: Patency up to 14 months was achieved (mean follow-up 6.5 months) with these stented grafts. The use of stented grafts appears to be associated with decreased blood loss, a less invasive insertion procedure, reduced requirements for anesthesia, and a limited need for an extensive dissection in the traumatized field. These advantages are particularly important in patients with central arteriovenous fistulas or false aneurysms who are critically ill from other coexisting injuries or medical comorbidities. Conclusions: The use of stented grafts already appears justified to treat traumatic arterial lesions in critically ill patients. Although the early results with the seven cases in this report are encouraging, documentation of long-term effectiveness must be obtained before these devices can be recommended for widespread or generalized use in the treatment of major arterial injuries. (J VASC SURG 1994;20:466-73.)

Purpose: The absence of sufficient length of suitable autologous vein occasionally prohibits the treatment of severe distal lower extremity arterial occlusive disease with a standard distal bypass originating from the common femoral artery. During the past 11 years, we have therefore selectively performed short distal bypasses originating from the infrapopliteal arteries in patients with limb-threatening ischemia and occlusive lesions limited to the distal tibial and peroneal arteries. This report summarizes our experience with these tibial artery based distal bypasses. Methods: Forty-two distal lower extremity arterial bypasses originating from infrapopliteal arteries in 41 patients were performed over an 11-year period. Autologous vein was used as the bypass conduit in all cases. Extensions from a more proximal bypass were excluded. Results: The primary patency rate of these tibiotibial bypasses was 77% at 1 year and 62% after 5 years. The limb salvage rate after 5 years was 74%. The perioperative mortality rate was low (2%), but the 5-year patient survival rate (64%) was similar to that with more standard lower extremity arterial reconstructive procedures. Conclusions: Tibiotibial bypass is an effective limb salvage procedure in carefully selected patients with distal tibial artery occlusive disease and limited autologous vein. It offers a durable means of distal revascularization in circumstances in which a standard operation might not be desirable or possible. (J V ASC S URG 1994;20:61-9.)

This report describes the use of an endoluminally placed stented graft to repair a large (2.6 by 2.6 by 15 cm) popliteal aneurysm in a 63-year-old man with advanced heart disease. Two balloon-expandable stents were attached to a 6 mm polytetrafluoroethylene graft, which was inserted with the patient receiving local anesthetic through a proximal superficial femoral artery arteriotomy. Repeat arteriography and duplex ultrasonography performed up to 3 months after the procedure documented graft and distal artery patency and complete aneurysmal exclusion without distal emboli. This experience demonstrates technical feasibility and early graft patency. However, additional experience and follow-up will be needed to assess the value of this minimally invasive procedure in the management of popliteal aneurysmal disease. (J VASC SURG 1994;19:754-7.)

Controversy continues as to whether percutaneous transluminal angioplasty (PTA) or surgical revision is the ideal modality for the treatment of failing grafts. This prompted a histopathologic analysis of failing human vein graft segments subjected to ex vivo balloon dilatation to define variables responsible for the discrepant results. Fifteen vein graft lesions from 14 patients with failing infrainguinal bypasses were recovered after surgical excision. Each graft lesion was focal and uniform in length (2.1 +/- 0.3 cm). Rings sectioned from adjacent regions of each vein graft lesion before and after balloon inflation were processed for histologic study, photomicrography, and image analysis. Angioplasty balloon size was selected on the basis of preoperative arteriograms. Graft lesions were divided into three groups based on lesion thickness and the degree of fibrosis and cellularity seen on sections stained with Masson's trichrome. The luminal area before angioplasty was not significantly different for the three groups (p0.2). Vein grafts with thick intimas (group 1) had significantly less luminal dilatation after angioplasty as compared with less thick intimal lesions (groups 2 and 3; p0.001). Those lesions with varying degrees of cellularity (groups 2 and 3) showed no significant differences in luminal diameter after angioplasty. However, the cellular lesions in group 2 consistently formed multiple intimal flaps that could produce PTA failures even with good luminal restoration. The varying histology of vein graft lesions and associated differences in intimal thickness and cellularity may be responsible for the inconsistent results following PTA. Estimates of wall thickness before angioplasty, particularly in the intimal area, may be helpful in evaluating which lesions might benefit most from PTA.

Objective: Subintimal angioplasty (SIA) has been advocated to treat long segment lower extremity arterial occlusions, but many question its value. We evaluated the role of SIA in a group of patients with severe lower extremity arterial occlusive disease. Methods: During a 2.5-year period, 39 patients with arterial occlusions (median length, 8 cm; range, 2 to 31 cm) were treated on an intention-to-treat basis with SIA. Twenty-five patients had gangrene, five had rest pain, and nine had disabling (

Purpose: Incomplete endovascular graft exclusion of an abdominal aortic aneurysm results in an endoleak. To better understand the pathogenesis, significance, and fate of endoleaks, we analyzed our experience with endovascular aneurysm repair. Methods:Between November 1992 and May 1997, 47 aneurysms were treated. In a phase I study, patients received either an endovascular aortoaortic graft (11) or an aortoiliac, femorofemoral graft (8). In phase II, procedures and grafts were modified to include aortofemoral, femorofemoral grafts (28) that were inserted with juxtarenal proximal stents, sutured endovascular distal anastomoses within the femoral artery, and hypogastric artery coil embolization. Endoleaks were detected by arteriogram, computed tomographic scan, or duplex ultrasound. Classification systems to describe anatomic, chronologic, and physiologic endoleak features were developed, and aortic characteristics were correlated with endoleak incidence. Results: Endoleaks were discovered in 11 phase I patients (58%) and only six phase II patients (21%; p < 0.05). Aneurysm neck lengths 2 cm or less increased the incidence of endoleaks (p < 0.05). Although not significant, aneurysms with patent side branches or severe neck calcification had a higher rate of endoleaks than those without these features (47% vs 29% and 57% vs 33%, respectively), and patients with iliac artery occlusive disease had a lower rate of endoleaks than those without occlusive disease (18% vs 42%). Endoleak classifications revealed that most endoleaks were immediate, without outflow, and persistent (71% each), proximal (59%), and had aortic inflow (88%). One patient with a persistent endoleak had aneurysm rupture and died. Conclusions: Endoleaks complicate a significant number of endovascular abdominal aortic aneurysm repairs and may permit aneurysm growth and rupture. The type of graft used, the technique of graft insertion, and aortic anatomic features all affect the rate of endoleaks. Anatomic, chronologic, and physiologic classifications can facilitate endoleak reporting and improve understanding of their pathogenesis, significance, and fate. (J Vasc Surg 1998;27:69-80.)

PurposeIt is widely believed that chronic renal insufficiency (CRI) greatly increases the risk associated with endovascular abdominal aortic aneurysm repair (EVAR) and is a relative contraindication to the procedure and to the use of intra-arterial contrast agents (IACA). We reviewed a 5-year EVAR experience to determine whether the procedure and use of IACA have an important deleterious effect on renal function in patients with and without pre-existing CRI.MethodsEndovascular aneurysm repair (EVAR) was performed in 200 patients with a variety of endografts, with intra-arterial contrast agents. The patients were retrospectively assigned to three groups on the basis of preoperative serum creatinine concentration (Cr): group 1 (n = 108), Cr less than 1.5 mg/dL (normal range); group 2 (n = 65), Cr 1.5 to 2.0 mg/dL; group 3 (n = 27), Cr 2.1 to 3.5 mg/dL. No patients had undergone hemodialysis. In groups 2 and 3, patients received hydration perioperatively, and received mannitol intraoperatively; no nephrotoxic drugs were administered during the procedure, other than nonionic contrast agent (Omnipaque 350).ResultsThe incidence of postoperative complications between the three study groups was not statistically different. In group 1 a transient increase in serum Cr (>30% over baseline and >1.4 mg/dL) was noted in three patients (2.7%), two of whom (1.9%) required temporary hemodialysis and one (0.9%) who died of renal failure. In group 2 a transient increase in serum Cr was noted in two patients (3.1%); both patients (3.1%) required temporary hemodialysis, and one patient (1.5%) died of renal failure. In group 3 a transient increase in serum Cr was noted in two patients (7.4%); one patient (3.7%) required temporary hemodialysis, and one patient (3.7%) died of renal failure. Perioperative hypotension significantly increased the risk for elevated serum Cr and death (P < .05), and larger contrast volume was associated with an increase in serum Cr (P < .05) during the postoperative period.ConclusionsEVAR with intra-arterial contrast agents can be accomplished in patients with chronic renal insufficiency who do not require dialysis, with limited and acceptable morbidity and mortality, similar to that observed with open aneurysm repair. Contrary to other reports in which perioperative precautions were not used, our study shows that with EVAR the risk for worsening renal failure, dialysis, and death is only slightly, and not significantly, greater in patients with preoperative chronic renal insufficiency compared with patients with normal renal function. Perioperative hypotension and increased contrast volume are significant risk factors for postoperative increase in serum Cr and death. With appropriate precautions such as averting perioperative hypotension and limiting the volume of nonionic contrast agents, elevated Cr need not be a contraindication to EVAR with intra-arterial contrast agents.

Purpose: This report describes our experience with endovascular repair of aortic and iliac anastomotic aneurysms. Methods: Between June 1994 and March 1996, 12 noninfected aortic or iliac anastomotic aneurysms in 10 patients who had serious comorbid medical conditions that precluded or made difficult standard operative repair were treated using endovascular grafts. No patient in this study had a history of fever, leukocytosis, or computed tomographic evidence of a periprosthetic fluid collection that was suggestive of infection of the original graft. Endovascular grafts composed of polytetrafluoroethylene and balloon-expandable stents were introduced through a femoral arteriotomy and were placed using over-the-wire techniques under C-arm fluoroscopic guidance. Results: Endovascular grafts were successfully inserted in all patients with aortic or iliac anastomotic aneurysms. There were no procedure-related deaths, and complications included one postprocedure wound hematoma and one perioperative myocardial infarction. Graft patency has been maintained for a mean of 16.1 months, with no computed tomographic evidence of aneurysmal enlargement or perigraft leakage. Conclusions: Endovascular grafts appear to be a safe and effective technique for excluding some noninfected aortoiliac anastomotic aneurysms in high-risk patients and may become a treatment option in all patients who have clinically significant lesions. (J Vasc Surg 1997 26:210-21.)

Objectives Lower extremity embolization occurs during aortoiliac aneurysm repair and may require major amputation when distal arteries are occluded. Because nonoperative treatments are often ineffective, we evaluated an aggressive operative approach. Methods In the past 11 years, we performed 328 endovascular and 350 open aortoiliac aneurysm repairs. Excluding cases of embolization to iliac, femoral, popliteal, and more proximal tibial vessels, which were treated in a standard fashion, foot ischemia severe enough to produce cadaveric, pregangrenous, or gangrenous skin changes occurred from more distal embolization after seven endovascular and three open aortoiliac aneurysm repairs. Six of these 10 patients underwent thromboembolectomies of both their dorsalis pedis and perimalleolar posterior tibial arteries ≤4 hours of their original operation. In the other four patients, treatment was delayed 7 to 10 days. Because of progressive foot ischemia, arteriography was performed. From these results, four bypasses (3 autologous vein, 1 polytetrafluoroethylene graft) were performed to the transverse metatarsal arch, dorsalis pedis, perimalleolar peroneal artery, or perimalleolar anterior tibial artery. Results Patency and limb-salvage rates for both thromboembolectomy and bypass procedures were 100% at a mean follow-up of 3.0 years (range, 5 months-8 years). Conclusions Perimalleolar and foot artery thromboembolectomy and bypasses to arteries as distal as the metatarsal arch can be effective treatment for distal embolization from aortoiliac aneurysm repair. Even when cadaveric, pregangrenous, or gangrenous lesions are present, distal arteriography and operative treatment (thromboembolectomy or bypass) may be indicated to successfully salvage the foot.

Objective: Hypogastric artery (HA) occlusion during aortic aneurysm repair has been associated with considerable morbidity. We analyzed the consequences of interrupting one or both HAs in the standard surgical or endovascular treatment of aortoiliac aneurysms (AIAs). Methods: From 1992 to 2000, 154 patients with abdominal aortic aneurysms (n = 66), iliac aneurysms (n = 28), or AIAs (n = 60) required interruption of one (n = 134) or both (n = 20) HAs as part of their endovascular (n = 107) or open repair (n = 47). Endovascular treatment was performed with a variety of industry- or surgeon-made grafts in combination with coil embolization of the HAs. The standard surgical techniques included oversewing or excluding the origins of the HAs and extending the prosthetic graft to the external iliac or femoral artery. Results: There were no cases of buttock necrosis, ischemic colitis requiring laparotomy, or death when one or both HAs were interrupted. Persistent buttock claudication occurred after 16 (12%) of the unilateral and 2 (11%) of the bilateral HA interruptions. Impotence occurred in 7 (9%) of the unilateral and 2 (13%) of the bilateral HA interruptions. Minor neurologic deficits of the lower extremity were observed in 2 (1.5%) of the patients with unilateral HA interruption. Conclusions: Although HA flow should be preserved if possible, selective interruption of one or both HAs can usually be accomplished safely during endovascular and open repair of anatomically challenging AIAs. We believe other comorbid factors such as shock, distal embolization, or the failure to preserve collateral branches from the external iliac and femoral arteries may have contributed to the morbidity in other reports of HA interruption. (J Vasc Surg 2001;33:S27-32.)

Prosthetic graft seromas is a rare complication that has been traditionally managed with open methods using partial graft replacement and open drainage. We report the first two cases of hemodialysis graft seromas successfully treated with a covered stent. Both patients underwent arteriovenous graft placement from the brachial artery to the axillary vein using a standard wall, tapered 4 to 7 mm polytetrafluoroethylene graft, but developed a seroma at the arterial end of the graft. Unsuccessful attempts were made to treat these seromas with percutaneous and open drainage. In both patients, an 8 mm x 50 mm Wallgraft (Boston Scientific, Natick, Mass) was retrogradely deployed "bareback" at the arterial end of the graft allowing for complete resolution of the graft seromas.