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We present two cases of ascending aortic pseudoaneurysm exclusion with off-the-shelf aortic stent grafts. The right common carotid artery was used for access to facilitate graft delivery. Control of graft deployment was aided using a compliant right atrial occlusion balloon to lower cardiac output at the time of deployment. Transesophageal echocardiography facilitated the sizing and positioning of the right atrial balloon and was used to survey the heart and ascending aorta on successful exclusion of the pseudoaneurysm. These simple maneuvers made an uncommon procedure straight forward, predictable, and successful.

In this study, we subjected vascular smooth muscle cells (VSMC) to acute and chronic high glucose conditions under physiologically relevant levels of cyclic strain and low wall shear forces to compare phenotypic modulation and thus conceptualize a dynamic-disease test model which captures cellular response more accurately in comparison with static cultures.P2-P6 rat aortic smooth muscle cells were seeded on type I collagen-coated silicone membranes and subjected to 0-7% cyclic strain at 1 Hz and 0.3 dynes/cm(2) shear stress from flow for 24 hr under acute (25 mM d-glucose, 84 hr) and chronic high glucose conditions (25 mM d-glucose, 3-4 weeks). Samples were analyzed for cell proliferation, percent apoptosis, cellular hypertrophy, and expression levels of smooth muscle contractile state-associated markers with 0.05 level of significance.Concomitant application of cyclic strain and flow shear resulted in an overall increase in proliferation of VSMCs under both acute and chronic high glucose conditions as compared with normal glucose control (P 0.0001). Application of both cyclic strain and cyclic strain shear resulted in a significant increase in percent apoptosis with chronic high glucose treatment in comparison with both normal glucose controls (P 0.0001) and acute high glucose (P 0.0001). Cellular hypertrophy as estimated by measuring cell area and aspect ratio revealed a significantly altered morphology due to concomitant loading under chronic high glucose conditions with significantly higher cell area (P 0.0001) and lower aspect ratio (P 0.0001) indicative of a relatively rounded morphology as compared with normal glucose controls. Western blot analysis demonstrated reduced expression of SM α-actin (P 0.0001), calponin (P 0.0001), and SM22α (P = 0.0008) for concomitant loading under chronic high glucose treatment as compared with normal glucose controls.Concomitant application of cyclic strain and low wall shear stress resulted in greater phenotypic modulation of VSMCs due to chronic high glucose treatment as compared with normal glucose controls, thus implicating cellular-response differences which may impact progression of in-stent restenosis in diabetic patients with poorly controlled hyperglycemia. Similarity of VSMC response from our study to existing preclinical models of diabetes and reports of altered phenotype of VSMCs isolated from diabetic patients substantiate the relevance of our dynamic disease test model.

The phenotypic shift of smooth muscle cells (SMCs) from contractile to synthetic phenotype after endovascular stenting has been deemed to be the predominant cause of restenosis. Although substrate topography has been shown to affect SMC response for a variety of polymers, effect of topography on phenotype of SMCs has not been well studied for endovascular stent materials. Thus, the objective of the present study was to evaluate SMC phenotype, manifested in morphology, proliferation, and contractile marker smooth muscle α-actin expression, as a function of 316L stainless steel topography. Results of this study showed that the cells grown on micro-grooved surface (groove depth: 13 μm) were significantly more elongated than those on the electropolished surface. Ascertained by repeated proliferation studies, cells grown on micro-grooved surface demonstrated a significantly lower proliferation rate relative to the electropolished surface. An enhanced expression of smooth muscle α-actin grown on micro-grooved surface was also found near confluence. Furthermore, cells on electropolished surface demonstrated a substantial loss of smooth muscle α-actin between days 1 and 4. Therefore, given the favorable SMC response reported in this study, our findings suggest that a micro-grooved topography might prove beneficial for endovascular stent applications.

Background Most patients with critical limb ischemia (CLI) have multilevel infrainguinal peripheral arterial disease (M-PAD). One-third of CLI patients will have isolated tibial disease (ITD). The treatments for multilevel disease or ITD differ depending on whether open or endovascular procedures are used, but we questioned whether outcomes from these procedures differ. We evaluated outcomes of CLI patients after open and/or endovascular revascularization for CLI and assessed the impact of disease distribution. Methods Four hundred forty-six CLI patients (Rutherford 4-6) who underwent revascularization from 2001 to 2005 were evaluated arteriographically and followed after revascularization with noninvasive testing. Based on arteriographic data, all patients with ITD (occlusions in one or more tibial arteries) were compared with patients with occlusive femoropopliteal disease with or without concomitant tibial occlusions (M-PAD). Patients with disease solely above the inguinal ligament were excluded. Clinical data (survival, amputation-free survival, primary patency, secondary patency, limb salvage, maintenance of ambulation, and maintenance of living status) were acquired from a prospective vascular database, allowing the comparison of revascularization outcomes according to disease distribution. Results In this study, 36% of patients had ITD and 64% presented with M-PAD. The severity of ischemia at presentation was rest pain (28.5%), ulceration (42.3%), and gangrene (29.1%). In this study, 92% presented exclusively with infrainguinal disease, and 8% presented with both suprainguinal and infrainguinal disease. Risk factors included diabetes mellitus (61.2%), smoking (61.0%), coronary artery disease (57.9%), hypertension (84.3%), hyperlipidemia (40.4%), obesity (15.5%), and chronic obstructive pulmonary disease (19.3%). In comparing the ITD and M-PAD groups, there was no difference in primary patency at 2 years. All other outcomes were statistically different out to 3 years including survival (50.4% vs. 62.6%; p = 0.0026, hazard ratio [HR] 0.669); amputation-free survival (35.1% vs. 50.2%; p = 0.0062; HR 0.595); limb salvage (65.2% vs. 74.4%; p = 0.0062; HR 0.595); maintenance of ambulation (68.9% vs. 76.9%; p = 0.0352; HR 0.644); maintenance of living status (79.0% vs. 84.8%; p = 0.0403; HR 0.599); and secondary patency (66.8% vs. 74.8%; p = 0.0309; HR 0.665). Multivariate analyses reveal that ITD is not an independent predictor of outcome after controlling for confounding factors, of which tissue loss and end-stage renal disease correlate most consistently with poor clinical outcomes. Conclusion After revascularization for CLI, ITD carries a worse prognosis (amputation-free survival, limb salvage, survival, maintenance of ambulation, and independent living status) compared with patients with M-PAD, despite the “greater” disease burden in M-PAD patients. ITD patients are more likely to have confounding factors such as diabetes mellitus, renal disease, and worse ischemia at presentation than those with M-PAD. The recognition of ITD may be helpful in identifying high-risk patients but is not an independent risk factor for poor outcomes.

Long-term anatomical changes of the thoracic aorta which may affect long-term outcome of blunt aortic injuries treated with endovascular stent grafts are unknown. The purpose of this study was to examine the natural history of thoracic aortic diameter with progressing age.One thousand consecutive thoracic computed tomographic scans performed for nonthoracic aortic pathology on patients aged 15-99 (mean 59.4) were examined, and thoracic aortic diameter immediately adjacent to the left subclavian artery was measured. Factors possibly influencing diameter, including age by decade of life, race, gender, history of hypertension (HTN), diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), and tobacco use, were examined. Factors were compared using Student's t-test.The differences in mean diameters of the thoracic aorta by gender (male=27.1 vs. female=26.0, p=0.87), race (Caucasian=26.6 vs. non-Caucasian=26.3, p=0.10), presence of HTN (yes=25.8 vs. no=24.9, p=0.36), COPD (yes=26.3 vs. no=25.4, p=0.21), DM (yes=26.1 vs. no=25.3, p=0.12), and tobacco use (yes=26.3 vs. no=25.0, p=0.18) were not significant. However, differences in mean diameter increased significantly over time with age. Patients under 40 years old had mean aortic diameters of 22.92 mm compared to 27.09 mm (p0.001) for patients over 40. The mean aortic isthmus diameter showed an approximately 1cm increase when comparing octogenarians to teenagers.The diameter of the aortic isthmus increases substantially with age. These findings suggest that long-term surveillance is warranted for trauma patients with aortic stent grafts, to monitor the natural history and to assess for possible late complications.

Following balloon angioplasty, denudation of endothelial cells exposes vascular smooth muscle cells (SMCs) to normally unseen shear forces from blood flow. In vivo studies investigate the response to angioplasty injury, but limited studies have been performed using in vitro systems. In order to study SMC response in vitro, a concurrent shear and tensile forces simulator has been developed to provide clinically significant levels of strain and shear stresses in addition to simulating forces similar to those during balloon angioplasty. In this acute study (8 hr), rat aortic SMCs demonstrated significant cell proliferation following applied increased tensile forces of angioplasty injury and shear exposure when compared to lower levels of tensile exposure similar to a normal physiological level, with an average 75% increase in the number of cells of the injury group compared to the normal dynamic group. SMCs exposed to balloon angioplasty injury and concurrent shear and tensile mechanical forces demonstrated decreased expression of the contractile phenotypic marker smooth muscle alpha-actin. These findings demonstrate the efficacy of the developed model for in vitro angioplasty and the simulated mechanical environment to the cells. This provides an in vitro model to isolate the effects of concurrent mechanical forces and could also potentially act as a preliminary step toward use in pharmaceutical research for reduction or prevention of SMC proliferation due to altered mechanical forces during endovascular procedures.

With the emergence of endovascular surgery, there is a perception that open aortic procedures for aneurysmal and occlusive disease have become more difficult. To test this hypothesis, two consecutive groups of patients undergoing open aortic surgery for aneurysmal (AAA) and occlusive (AIOD) disease before and after the establishment of an endovascular program (EP) were analyzed. The pre-EP patient group (January 1996 through December 1997) consisted of 112 patients (52 with AAA, 60 with AIOD) and the post-EP patient group (January 2000 through December 2001) consisted of 142 patients (72 with AAA, 70 with AIOD). The pre-EP AAA group was compared with the post-EP AAA group and the pre-EP AIOD group was compared with the post-EP AIOD group. Factors analyzed included patient demographics, comorbidities, and operative outcomes. Statistical comparisons were carried out using Fisher’s exact test for proportions and the Wilcoxon rank-sum test for medians. There were no statistical differences in patient demographics between the pre-EP and post-EP groups, regardless of procedure. When considering AAA repair, there was a higher rate of hypertension and hypercholesterolemia in the pre-EP group and a higher number of total comorbidities per patient in the post-EP group. There was also an increased incidence of perioperative blood transfusion in the post-EP group. When considering open procedures for AIOD, there was an increased rate of hypertension and history of previous abdominal operation in the post-EP group. There also was an increased incidence of perioperative blood transfusion. Other than these factors, there were no statistically significant differences between the pre- and post-EP groups with regard to mortality, complication rate, length of procedure, blood loss, length of ICU stay, or length of hospital stay for either the aneurysmal patients or the occlusive disease patients. With only minor exception, endovascular surgery has not appreciably increased the complexity of open aortic operations performed for either AAA or AIOD.

The treatment of choice for renal artery occlusive disease has shifted from open repair to percutaneous angioplasty and stenting in many institutions. Whether this change in treatment modality will lead to altered and, perhaps, relaxed indications for intervention is unclear. We reviewed our experience to determine if a shift from open surgery to percutaneous management of renal occlusive disease was associated with changes in either indications for intervention or patient outcomes. Over an 8-year period, 165 patients had intervention for renal artery stenosis by our vascular surgery teaching service. Over the period there was a dramatic increase in interventions per year (4 patients 1994 to 57 patients 2001). There was also a shift from open to endovascular management. Patient demographics and indications for intervention showed no difference between open and endovascular groups. Outcome analysis revealed similar technical success rates between groups but a significantly higher morbidity and mortality rate in the surgical group. A shift from open to percutaneous treatment of renal artery occlusive disease led to a significant increase in patient volume. This increase occurred without a change in patient demographics or indications for therapy, and appeared to reflect an increase in patient referrals.

Many patients are not considered candidates for radiocephalic fistula (RCF) or brachiocephalic fistula (BCF) creation or have fistulas that do not mature because the cephalic vein is too deep or tortuous to be accessed. Other patients have not been candidates for the basilic vein transposition (BVT) because limited length of adequate caliber vein precludes subcutaneous tunneling of the vein. In an effort to maximize arteriovenous fistula (AVF) utilization, we developed an adjunctive procedure designed to make the deep or tortuous fistula accessible to needle cannulation. The fistula elevation procedure (FEP) involves mobilization of the fistula, approximation of the subcutaneous tissue beneath the fistula, and subcuticular skin closure over the fistula. The procedure enhances the accessibility of the fistula by placing it in a more superficial position. The overlying cicatrix also acts as a guide for dialysis needle insertion. Between June 1998 and January 2001, 45 patients underwent a natural AVF that could not be accessed secondary to venous depth, tortuosity, or length. In each case, a FEP was performed to salvage the fistula. The FEP was performed as an adjunct to a BCF in 20 patients, a RCF in 7 patients, and a BVT in 8 patients. The FEP is a simple procedure that enhances AVF utilization by making the fistula more accessible to dialysis needle cannulation. The procedure is particularly helpful in obese patients who would not traditionally be considered candidates for natural AVF creation.

Arteriovenous (AV) access graft infection results in disruption of dialysis and usually necessitates graft removal when the entire graft is involved. The management of an isolated infected segment of an otherwise noninfected AV access graft, however, remains controversial. To evaluate the utility of segmental bypass and partial graft excision for the treatment of an isolated infected AV access graft segment, 17 consecutive cases in 12 patients (7 females/5 males; 14 arm grafts/3 leg grafts; median age = 69 years) were analyzed on a vascular teaching service that performed 1244 total access procedures from January 1995 through February 1999. Infections presented as a draining sinus or a sinus with hemorrhage emanating from an area over the graft. At operation, the infected sinus was covered by a transparent occlusive dressing and the graft was explored through clean incisions proximal and distal to the infected segment. If the graft was incorporated and free of infection, a piece of expanded polytetrafluoroethylene (ePTFE) was anastomosed proximally end-to-end and tunneled through noninfected tissues around the infected sinus. After the distal anastomosis was performed, the skin incisions were closed and covered with occlusive dressings. The infected graft segment was then removed through the infected sinus wound. The technique of segmental bypass and partial graft excision results in predictable eradication of infection, graft salvage, and maintenance of uninterrupted dialysis in patients presenting with an isolated AV dialysis access infection.

The management of vascular prosthetic graft infections confined to the groin continues to be controversial. To critically evaluate this problem, we reviewed the records of our vascular registry from December 1992 through February 1995 and found 17 incidences of groin sepsis involving a vascular prosthesis in 10 patients. These included a proximal prosthetic femoropopliteal bypass (n = 6), an aortobifemoral graft limb (n = 5), an ileofemoral bypass (n = 3), a prosthetic femoral patch (n = 2), and an aortofemoral/femorofemoral bypass (n = 1). The mean age of these patients was 65 years. Six patients were diabetic, four were on systemic steroids, and two were diabetic and on steroids. All infections were Szilagyi grade III including three in which the patients presented with local hemorrhage. Treatment consisted of irrigation, radical debridement with or without in situ graft replacement, and local rotational muscle flap coverage in nine cases, graft excision with extra-anatomic (obturator ileofemoral bypass) graft replacement in six cases, and excision alone in two cases. Of the 17 infections treated operatively and followed from 1 week to 18 months (median 5 months), eight (47%) showed no evidence of recurrence, six (35%) recurred, two (12%) caused early death, and one resulted in a thrombosed graft requiring extra-anatomic reconstruction. Of the nine infected grafted treated locally with muscle flaps, six showed recurrent infection from 3 weeks to 15 months and one thrombosed for a total local treatment failure rate of 78%. Only two grafts are free of infection at 4 and 5 months, respectively. Of the six incidences of infection treated with obturator bypass, four (66%) are free of infection and two resulted in patient death; both infections treated with excision alone were eradicated but resulted in a major lower extremity amputation. These data question the growing acceptance of debridement and local muscle flap coverage for the treatment of all prosthetic vascular graft infections confined to the groin, especially in patients who are diabetic or on systemic steroids.