Faculty Bibliography

PURPOSE: Penetrating subclavian arterial injuries are often difficult to treat. Standard surgical techniques require wide exposure and dissection in traumatized areas, which is often challenging. This report summarizes the early results of endovascularly placed stented grafts for the treatment of penetrating subclavian arterial trauma. METHODS: Six patients with penetrating injuries of the subclavian artery had stented grafts inserted to repair five pseudoaneurysms and one arteriovenous fistula. The stented grafts consisted of a polytetrafluoroethylene graft sutured over a balloon-expandable Palmaz stent. The devices were inserted from an ipsilateral brachial arteriotomy and deployed using fluoroscopic guidance in the operating room. RESULTS: Immediate success was obtained in all procedures (100%). All patients continue to have patent grafts with a follow-up ranging from 7 to 30 months (mean 19 months). The only procedure-related complication was the need for a brachial artery patch angioplasty at the site of device insertion in the first patient. There was one other patient who developed a stent fracture at 8 months; a second stent was inserted. Duplex studies up to 24 months later show no recurrence in this patient. CONCLUSIONS: Endovascular stented grafts offer an effective, less invasive alternative to standard techniques in treating traumatic arterial lesions. Early results are encouraging, but long-term follow-up will be necessary to fully delineate the effectiveness of this technique

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 (7.7 mm +/- 0.33 standard deviation) compared with the uncovered (6.7 mm +/- 0.85 standard deviation) portions (P < .01). 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

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

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 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 which includes 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

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: Thrombolytic therapy is widely used in the treatment of peripheral arterial occlusion, but prospective, randomized comparisons with standard therapy remain few. A multicenter trial of thrombolysis or peripheral arterial surgery (TOPAS) was organized to compare critically the use of recombinant urokinase (rUK) or surgery for the initial treatment of acute lower-extremity ischemia. Phase I of the trial was designed as a dose-ranging trial to evaluate the safety and efficacy of three doses of rUK in comparison with surgery. METHODS: In a multicenter, prospective, double-blind comparison, 213 patients who had acute lower-extremity ischemia for 14 days or fewer were randomized to one of two groups. The first group received one of three dosages of rUK (catheter-directed at 2000, 4000, or 6000 IU/min for 4 hours, then 2000 IU/min to a maximum of 48 hours). The second group underwent surgery. Successful thrombolysis was followed by surgical or endovascular interventions when anatomic lesions responsible for the occlusion were unmasked. Patients were followed-up for 1 year; data were evaluated on an intent-to-treat basis. RESULTS: The 4000 IU/min rUK dosage was chosen as the most appropriate thrombolytic regimen because it maximized lytic efficacy against the risk of bleeding. Complete (> 95%) lysis of thrombus was achieved in 71% of the 49 patients who were randomized to the 4000 IU/min group, with a mean infusion time of 23 hours. In contrast, complete lysis was achieved in 67% of patients who received 2000 IU/min and in 60% of patients who received 6000 IU/min. Hemorrhagic complications occurred in 2% of the 4000 IU/min group versus 13% of the 2000 IU/min group (p = 0.05) and 16% of the 6000 IU/min group (p = 0.03). In a comparison of the 4000 IU/min group with the surgical group, the 1-year mortality rate (14% vs 16%) or amputation-free survival rate (75% vs 65%) did not differ significantly. The frequency and magnitude of surgery in the patients randomized to rUK were decreased (p < 0.001). CONCLUSION: The preliminary results suggest that an initial rUK dose of 4000 IU/min is safe and efficacious in the treatment of acute lower-extremity ischemia. rUK therapy is associated with limb salvage and patient survival rates similar to those achieved with surgery, concurrent with a reduced requirement for complex surgery after thrombolytic intervention