Faculty Bibliography

Vascular injuries caused by blunt or penetrating trauma can be challenging to diagnose and treat, particularly when they involve central vessels. Endovascular treatment for vascular trauma includes the placement of embolization coils and intravascular stents and the employment of 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 a traumatized field. These advantages are especially important in patients with central arteriovenous fistulas or false aneurysms, particularly those who are critically ill from other coexisting injuries or medical comorbidities. In these circumstances, the use of stented grafts already appears justified to treat traumatic central arterial lesions. Endovascular grafts are important tools for the treatment of vascular trauma, and they should be included in the armamentarium of the vascular surgeon

PURPOSE: To develop an animal model for the acute and chronic monitoring of pressure within abdominal aortic aneurysms (AAAs) to be treated with endovascular grafts. METHODS: A strain-gauge pressure transducer was placed within an AAA created from a prosthetic vascular graft. Prosthetic aneurysms were implanted into 17 canine infrarenal aortas. The intra-aneurysmal pressure was monitored and correlated with noninvasive forelimb sphygmomanometry for 2 weeks. After this time, an intravascular manometer catheter was passed into the aneurysm. Simultaneous pressure measurements were obtained using the implanted strain-gauge pressure transducer, the manometer catheter, and the forelimb sphygmomanometer. Angiography was performed to assess intraluminal morphology, aneurysm anastomoses, and adjoining aortic vessels. In addition, two control animals underwent intra-aneurysmal pressure monitoring after standard surgical aneurysm repair. RESULTS: There was excellent correlation (r = 0.97) between the pressure measurements obtained with the implanted strain-gauge pressure transducer and the intravascular manometer. Close correlation was also observed between the implanted strain-gauge transducer and the forelimb sphygmomanometer (r = 0.88) during postprocedural monitoring. Intra-aneurysmal pressure was lowered dramatically by surgical exclusion (aneurysm: 15/5 +/- 7/4 mmHg; systemic: 124/66 +/- 34/17 mmHg; p < 0.001). The prosthetic aneurysms were successfully imaged with angiography. CONCLUSIONS: This animal model provides an accurate and reproducible means for measuring intra-aneurysmal pressure on an acute and chronic basis. It may be possible to use this model in the assessment of endovascular devices to determine their efficacy in reducing intra-aneurysmal pressure. Evaluation of complications associated with their use, such as patent aneurysm side branches, perigraft channels, and perianastomotic reflux, may also be possible

Endovascular treatment techniques have already replaced some vascular operations. The likelihood is that new endovascular techniques involving stents and stented grafts will replace additional vascular operations. All of these treatments involve the use of catheter-guidewire, balloon, and imaging modalities, particularly digital fluoroscopy. These modalities have already and will increasingly help to improve and simplify standard vascular operations such as thromboembolectomy, infrainguinal bypasses, and management of aneurysms and arteriovenous fistulas. Accordingly, vascular surgeons must become familiar with and use these endovascular methods and techniques. This can be accomplished in a variety of ways, including working as part of a multidisciplinary vascular treatment group in which various specialists collaborate to provide the best, most cost-effective care to vascular disease patients

The endovascular repair of abdominal aortic aneurysms has been investigated in a clinical setting since 1991. Although initially the procedure was performed using surgeon-made devices, it did not take long for the medical industry to realize the potential of this procedure. There are six commercially made devices, which are unique, each with their own strengths and weaknesses. This article describes the principal endovascular graft types that are currently under investigation as well as the strategies for their use. In addition, the inclusion criteria for endovascular repair of abdominal aortic aneurysms are discussed

Aortoiliac occlusive disease is a significant cause of lower extremity ischemic symptoms. Over the past two decades, most patients have been treated with a variety of surgical procedures, including aortofemoral and extra-anatomic bypasses. Most recently, percutaneous balloon angioplasty and stents have been successfully used for the treatment of limited iliac lesions. New endovascular grafts that combine vascular grafts with stents in a device with new characteristics may allow the successful treatment of patients with extensive aortoiliac occlusive disease in a less invasive fashion. In our early experience, the endovascular grafts were constructed with Palmaz balloon-expandable stents and standard polytetrafluoroethylene (PTFE) grafts. The 18-month primary and secondary patency rates were 89% and 100%, respectively, with a limb salvage rate of 94%. Endovascular grafts can be successfully used to treat patients with extensive aortoiliac occlusive disease, with excellent early results. Long-term results and further graft improvements will define their role in the treatment of patients with aortoiliac occlusive disease

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-1 beta], platelet-derived growth factor-AA [PDGF-AA], basic fibroblast growth factor [bFGF], interferon gamma [INF gamma], and tumor necrosis factor alpha [TNF-alpha]) 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-1 beta and bFGF occurred by 2 days. PDGF-AA expression paralleled the development of IH, peaking at 2 weeks and then declining. TNF-alpha expression increased at 1 week and remained elevated. INF gamma was seen only in control grafts. CONCLUSIONS: The coordinated early release of IL-1 beta and bFGF and the down-regulation of INF gamma seem to trigger an inflammatory response, thereby initiating IH. The process then is propagated by the release of PDGF-AA and TNF-alpha, 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

PURPOSE: The purpose of this study was to determine the outcome of patients with infrapopliteal artery graft infections (InfraPopGIs) who presented with graft infection distal to the popliteal artery. PATIENTS AND METHODS: Between July 1, 1979 and June 30, 1994, 27 patients presented with infrapopliteal artery graft infections (18 polytetrafluoroethylene [PTFE], 9 autologous vein). The infection involved the anastomosis in 22 cases (8 anterior tibial, 8 posterior tibial, 4 peroneal, 2 dorsalis pedis arteries) and was localized to the body of the graft in 5 cases (4 calf, 1 ankle). All bypasses were originally performed for limb salvage. Twelve patients with patent grafts and intact anastomoses were managed by complete graft preservation. Fifteen patients presented with occluded grafts (10), anastomotic hemorrhage (4), or systemic sepsis (1) and were treated by total or subtotal graft excision. RESULTS: The hospital mortality rate was 19% (5 of 27) and the amputation rate in survivors was 27% (6 of 22). These results were compared with a mortality rate of 13% (15 of 114; P > 0.05) and a limb loss rate of 10% (10 of 99)(P = 0.05) in 114 patients during this period who presented with infection proximal to the tibial arteries. Of 6 survivors with graft infections who required amputations, 5 lacked a suitable outflow artery for a secondary bypass and 1 developed progressive gangrene despite a patent secondary bypass. Among the other 16 survivors, 7 (44%) limbs remained viable without requiring a secondary bypass, 6 (37%) limbs were salvaged with successful preservation of patent grafts, and 3 (19%) required secondary bypasses to prevent limb loss. CONCLUSIONS: Patients presenting with infrapopliteal artery graft infections have higher amputation rates than patients with more proximal infected peripheral grafts. Selective graft preservation and selective revascularization when outflow arteries are available are essential adjuncts to minimize high rates of limb loss associated in patients with graft infections