Femoropopliteal System Research Articles

Outcomes of Octogenarians in Lower Extremity Endovascular Revascularization

Introduction - Endovascular surgery has evolved over the last decade to become a viable alternative for peripheral arterial disease (PAD) in high-risk patients due to medical comorbidities including advanced age. Efficacy trials continue to be done but high-risk patients are often preferentially offered endovascular interventions. The aim of this study was to compare outcomes between non-octogenarians and octogenarians following lower extremity endovascular revascularization (LEER). Methods - The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) LEER-targeted surgical cohort (2011-2014) was used to separately examine patients that underwent tibial (TB) or femoropopliteal (FP) angioplasty/stenting interventions. Disease, patient, clinical, and procedural characteristics were extracted (with data from 30 days of postsurgical follow-up), and evaluated using univariate/bivariate analyses (student t, χ2, and Fisher’s exact tests). Independent risk factors and trends were evaluated using multivariate logistic regression. Outcomes included 30-day mortality; readmission; loss of patency (LOP); as well as postoperative wound infection (WI), major amputation, and bleeding requiring intervention/transfusion. Results - The FP endovascular cohort consisted of 4193 patients. 30-day mortality was low (0.91%) and resulted in poor model-fit for both cohorts. Those 80+ years old had a slightly longer length of stay (LOS), higher physiological risk factors (PRF), similar elective vs emergent procedures, and a higher prevalence of CHF. The younger group exhibited more ESRD and HTN. 12.34% of patients were readmitted with age over 80 years, emergent procedures, PRF, ESRD, HTN, WI, and antiplatelet regimen as independent risk factors. Female gender was an independent risk factor for bleeding, as was smoking, emergent procedures, history of CHF, and WI. Major amputation was uncommon (2.55%); however, age, obesity, emergent procedures, bleeding, and WI were significant independent predictors. LOP (1.9%) was only independently predicted by emergent procedure. The TB endovascular cohort included 1105 patients. 30-day mortality was low (0.99%). There was no significant difference in LOS, CHF or hypertension between the older/younger groups. ESRD was more prevalent in the younger group, while the older group exhibited higher PRF. There were 19.5% of patients readmitted within 30 days, and was independently predicted by older age, and ESRD with 5.52% of patients undergoing a major amputation during follow-up. Obesity and bleeding were independent predictors. Bleeding was also examined as an outcome and was predicted by smoking, emergent admission, and ESRD. Conclusion - Following LEER involving the FP system, octogenarians were at a lower risk of major amputation and readmission but there was no difference in post-op WI or LOP. Following procedures involving the TB artery, octogenarians were at a lower risk of WI and readmission but a similar risk of amputation and bleeding. Considering the TB cohort had two-fold higher amputations and more readmissions than the FP cohort and that different risk factors impact the outcomes after each intervention, we must take this into account when discussing procedural options with patients. While sample size and selection bias may affect the results from databases such as ours, these results suggest that octogenarians may do just as well than non-octogenarians following LEER.

Management of Isolated Atherosclerotic Stenosis of the Common Femoral Artery: A Review of the Literature.

Common femoral endarterectomy (CFE) remains the standard of care for treatment of atherosclerotic stenosis of the common femoral artery (CFA). Endovascular interventions have become the first-line therapy for atherosclerotic disease of the aortoiliac and femoropopliteal systems. Recent reports have documented high rates of technical success and low rates of complications with endovascular management of CFA stenosis. This study is a contemporary review of the surgical and endovascular literature on the management CFA stenosis and compares the results of these methods. A search of OVID Medline identified all published reports of revascularization of isolated atherosclerotic CFA stenosis. For each study selected for review, the number of patients, number of limbs treated, percentage of patients with critical limb ischemia, and mean length of follow-up was recorded. Study end points included survival, primary patency, freedom from target lesion revascularization (TLR), freedom from amputation, and complications. The review included 7 CFE studies and 4 endovascular studies. Survival was similar between the groups. Primary patency was consistently higher with CFE compared to endovascular therapy. Freedom from TLR was lower with CFE compared to endovascular therapy. Morbidity and mortality was also higher with CFE compared to endovascular therapy. Freedom from amputation was not consistently reported in the endovascular studies. There is limited data to support endovascular treatment of isolated CFA atherosclerosis. CFE has durable results, but there is significant morbidity and mortality resulting from this procedure. Endovascular interventions have low rates of complications, high rates of technical success, good short-term patency but increased need for repeat interventions when compared to surgery. Further trial data comparing CFE with endovascular therapy is needed to guide the management of CFA stenosis.

Classification Systems for Lower Extremity Occlusive Disease

The management of lower extremity occlusive disease involves some of the most complex decision making in the field of vascular surgery. Patients with lower extremity occlusive disease often present with a wide spectrum of clinical manifestations ranging from mild intermittent claudication to severe ischemia with gangrene. Moreover, the prognosis and clinical management are dependent on the location and extent of the atherosclerotic disease burden, the presence of comorbid conditions that affect life expectancy and procedural patency, the revascularization options available, and the functional status of the patient. In an effort to bring order to this challenging disease, a number of lower extremity classification systems have been developed. This review discusses challenges of establishing a classification system, anatomic classification systems, classification systems based on presenting symptoms/clinical presentation, morbidity/mortality risk stratification systems, and disability classification systems. Tables outline the Society for Vascular Surgery runoff score, clinical categories of acute limb ischemia, Rutherford clinical categories of chronic limb ischemia, Fontaine clinical stages of chronic limb ischemia, LEGS (Lower Extremity Grading System) score used to recommend invasive treatment for patients with chronic lower extremity ischemia, WIfI (Wound Ischemia foot Infection) classification system grades, consensus estimate of 1 year amputation risk and likelihood of benefit of/requirement for revascularization based on WIfI spectrum score, predicted and observed 1-year outcomes (limb amputation, wound nonhealing) based on WIfI clinical stage classification, morbidity and mortality risk stratification methods, US social security administration disability criteria for patients with lower extremity occlusive disease and amputation, and criteria for rating impairment due to lower extremity peripheral vascular disease. Figures illustrate the TransAtlantic Inter-Society Consensus classification of aortoiliac and femoropopliteal lesions and Graziani System classes of progressive vascular disease severity and distribution in patients with diabetes mellitus presenting with foot wounds. This review contains 3 figures, 11 tables, and 35 references.

The natural history of duplex-detected stenosis after femoropopliteal endovascular therapy suggests questionable clinical utility of routine duplex surveillance

Duplex ultrasound (DU) surveillance (DUS) criteria for vein graft stenosis and thresholds for reintervention are well established. The natural history of DU-detected stenosis and the threshold criteria for reintervention in patients undergoing endovascular therapy (EVT) of the femoropopliteal system have yet to be determined. We report an analysis of routine DUS after infrainguinal EVT. Consecutive patients undergoing EVT of the superficial femoral artery (SFA) or popliteal artery were prospectively enrolled in a DUS protocol (≤1 week after intervention, then at 3, 6, and 12 months thereafter). Peak systolic velocity (PSV) and velocity ratio (Vr) were used to categorize the treated artery: normal was PSV <200 cm/s and Vr <2, moderate stenosis was PSV = 200-300 cm/s or Vr = 2-3, and severe stenosis was PSV >300 cm/s or Vr >3. Reinterventions were generally performed for persistent or recurrent symptoms, allowing us to analyze the natural history of DU-detected lesions and to perform sensitivity and specificity analysis for DUS criteria predictive of failure. Ninety-four limbs (85 patients) underwent EVT for SFA-popliteal disease and were prospectively enrolled in a DUS protocol. The initial scans were normal in 61 limbs (65%), and serial DU results remained normal in 38 (62%). In 17 limbs (28%), progressive stenoses were detected during surveillance. The rate of thrombosis in this subgroup was 10%. Moderate stenoses were detected in 28 (30%) limbs at initial scans; of these, 39% resolved or stabilized, 47% progressed to severe, and occlusions developed in 14%. Five (5%) limbs harbored severe stenoses on initial scans, and 80% of lesions resolved or stabilized. Progression to occlusion occurred in one limb (20%). The last DUS showed 25 limbs harbored severe stenoses; of these, 13 (52%) were in symptomatic patients and thus required reintervention regardless of DU findings. Eleven limbs (11%) eventually occluded. Sensitivity and specificity of DUS to predict occlusion were 88% and 60%, respectively. DUS does not reliably predict arterial occlusion after EVT. Stenosis after EVT appears to have a different natural history than restenosis after vein graft bypass. EVT patients are more likely to have severe stenosis when they present with recurrent symptoms, in contrast to vein graft patients, who commonly have occluded grafts when they present with recurrent symptoms. The potential impact of routine DU-directed reintervention in patients after EVT is questionable. The natural history of DU-detected stenosis after femoropopliteal endovascular therapy suggests questionable clinical utility of routine DUS.

Few predictors of massive deep vein thrombosis

Factors that predispose to thrombus propagation from the femoropopliteal veins to the pelvic veins are poorly understood. Our goal was to determine whether there are characteristics that identify patients with massive deep vein thrombosis (DVT). We compared the 122 (2.5%) patients presenting with massive DVT (pelvic plus lower-extremity DVT) to the 4,674 (97.5%) patients with isolated lower-extremity DVT from a prospective United States multicenter DVT registry. Patients with massive DVT were younger (59.4+/-18.9 years vs. 64.3+/-16.8 years; p<0.01), less likely to have hypertension (40% vs. 51%; p=0.02), and more likely to smoke (21% vs. 13%; p=0.02) and have ongoing radiation therapy (7% vs. 3%; p=0.02). The massive DVT group more commonly presented with extremity edema (80% vs. 69%; p<0.01) and erythema (21% vs. 12%; p<0.01) than the isolated lower-extremity DVT group. However, after multivariable logistic regression analysis, extremity erythema (adjusted odds ratio 1.86; 95% CI 1.13-3.04) was the only independent sequela of massive DVT and younger age (adjusted odds ratio 1.17 per decreasing decade of age; 95% confidence interval: 1.02-1.34) was the only independent predictor of massive DVT. Thrombus propagation from the femoropopliteal system cannot be reliably predicted using demographic or clinical characteristics.

Nontraumatic vascular emergencies: imaging and intervention in acute venous occlusion.

Risk factors for acute venous occlusion range from prolonged immobilization to hypercoagulability syndromes, trauma, and malignancy. The aim of this review article is to illustrate the different imaging options for the diagnosis of acute venous occlusion and to assess the value of interventional strategies for venous thrombosis treatment in an emergency setting.First, diagnosis and treatment of the most common form of venous occlusion, at the level of the lower extremities, is presented, followed by pelvic vein and inferior vena cava occlusion, mesenteric venous thrombosis, upper extremity occlusion, acute cerebral vein thrombosis, and finally acute venous occlusion of hemodialysis access.In acute venous occlusion of the lower extremity phlebography is still the reference gold standard. Presently, duplex ultrasound with manual compression is the most sensitive and specific noninvasive test. Limitations of ultrasonography include isolated distal calf vein occlusion, obesity, and patients with lower extremity edema. If sonography is nondiagnostic, venography should be considered. Magnetic resonance venography can differentiate an acute occlusion from chronic thrombus, but because of its high cost and limited availability, it is not yet used for the routine diagnosis of lower extremity venous occlusion only. Regarding interventional treatment, catheter-directed thrombolysis can be applied to dissolve thrombus in charily selected patients with symptomatic occlusion and no contraindications to therapy. Acute occlusion of the pelvic veins and the inferior vena cava, often due to extension from the femoropopliteal system, represents a major risk for pulmonary embolism. Color flow Doppler imaging is often limited owing to obesity and bowel gas. Venography has long been considered the gold standard for identifying proximal venous occlusion. Both CT scanning and MR imaging, however, can even more accurately diagnose acute pelvis vein or inferior vena cava occlusion. MRI is preferred because it is noninvasive, does not require contrast agent, carries no exposure to ionizing radiation, and is highly accurate and reproducible. Apart from catheter-directed thrombolysis, mechanical thrombectomy has proven to be a quick and safe treatment modality by enabling the recanalization of thrombotic occlusions in conjunction with minimal invasiveness and a low bleeding risk. Mechanical thrombectomy devices should only be used in conjunction with a temporary cava filter.Contrast-enhanced CT is at present considered the examination of choice for acute mesenteric vein occlusion which has mortality rates as high as 80%. Patients with proven acute mesenteric venous occlusion and contraindications to surgical therapy and no identified bleeding disposition without looming bowel ischemia or infarction are possible contenders to the less invasive percutaneous approach either by (in)direct thrombolysis or mechanical means. Ultrasonography is the primary imaging modality for the diagnosis of upper extremity thrombosis. Computed tomography and MRI are in addition helpful in diagnosing central chest vein occlusions. The interventionalist is rarely involved in the treatment of this entity. Catheter-directed thrombolysis is known to improve lysis rates. Together with balloon angioplasty good results have been obtained. If stenosis or thrombus remains after thrombolysis and angioplasty, stent placement should follow. Within the first two weeks, thrombosed dural sinus and cerebral venous vessels are typically hyperdense on CT compared with brain parenchyma; after the course of 2 weeks, the thrombus will become isodense. In MRI an axial fluid-attenuated inversion recovery sequence, an axial diffusion-weighted MRI, coronal T1-weighted spin-echo and T2-weighted turbo-spin-echo sequences, a coronal gradient-echo and a 3D phase-contrast venous angiogram should be performed. Local thrombolysis is needed only when patients have an exacerbation of clinical symptoms or imaging signs of worsening disease despite sufficient anticoagulation therapy. Acute occlusions of dialysialysis grafts and fistulae are a frequently encountered complication. Among the various methods described for acute occlusion screening, ultrasonography and MRI have been proven to be accurate and noninvasive; however, if immediate treatment can be anticipated, imaging should be performed directly by digital subtraction angiography before the percutaneous intervention. Initial percutaneous thrombectomy is very effective with success rates and patency rates comparable to those of surgical thrombectomy. A short thrombosis can be treated with balloon angioplasty alone, whereas an extensive thrombosis requires a combination of mechanical devices and/or thrombolytic agents with adjunctive balloon angioplasty.

LOWER-EXTREMITY ARTERIAL ENDOVASCULAR STENTING

Intraluminal arterial stenting for the management of arterial occlusive disease of the lower extremities has evolved over the years. Most stents are used to correct inadequacies of PTA or to correct a PTA complication. These include (1) restenosis within 90 days of PTA, (2) chronic iliac occlusion, (3) acute occlusions during PTA, (4) a significant residual gradient following PTA, (5) dissections longer than the angioplasty site, and (6) a 30% or greater residual stenosis after PTA. Both the Palmaz stent and the Wallstent have performed well in the iliac artery system. Their use in the femoropopliteal system has not been as successful and should be reserved for selected cases. Long-term anticoagulation is generally required for femoropopliteal stent patency. Placement in the lower superficial femoral or popliteal artery is best avoided. Re-angioplasty or additional stenting may be used to prolong patency, although with the risk of a second intervention. Progression of arteriosclerosis is a factor to consider when choosing an endoluminal treatment versus standard bypass.

Serial duplex ultrasound examinations for deep vein thrombosis in patients with suspected pulmonary embolism.

We have prospectively evaluated the need for serial venous duplex ultrasound examinations in an inpatient population with an initially normal study result. Patients were selected for study on the basis of clinical suspicion of pulmonary embolism and possible lower extremity deep vein thrombosis, a comorbid condition contributing to a nondiagnostic ventilation/perfusion lung scan, and an initially normal bilateral venous duplex ultrasound examination that included complete evaluation of the femoropopliteal system and the deep calf veins. Repeat duplex examinations were done during the same hospital admission between 5 and 14 days after the initial study. Ninety-four patients with an initially normal duplex ultrasound examination result had repeat studies done at an average of 7.9 +/- 2.6 days. Ninety-two examination results remained normal bilaterally. Two patients had isolated intramuscular calf vein deep vein thrombosis: one in the gastrocnemius system of both calves with associated calf tenderness at 11-day follow-up and one in a mid-calf soleal vein without associated symptoms at 10 days. No patients had any evidence of deep vein thrombosis in the femoropopliteal or tibioperoneal venous systems. Serial follow-up duplex ultrasound evaluation is unnecessary after an initially complete, normal study in patients with symptoms who have suspected pulmonary embolism and nondiagnostic ventilation-perfusion lung scans.

Diagnostic utility of color Doppler ultrasound in lower limb deep vein thrombosis in patients with clinical suspicion of pulmonary thromboembolism

The diagnosis of pulmonary thromboembolism is frequently based on ventilation-perfusion scintigraphy and ascending lower limb venography when pulmonary angiography is not available. The aim of this study is to compare color Doppler ultrasound against ascending venography in the evaluation of the lower limb deep vein system in patients with clinical suspicion of pulmonary embolism, with special attention to calf veins. We prospectively studied 30 patients with clinical suspicion of pulmonary embolism in whom a color Doppler ultrasound and venogram were performed with no more than a 3-h interval between both procedures. The diagnostic criteria was that of loss of venous compressibility. The ‘color’ ability was used to identify artery from vein. Out of 15 patients in whom a venogram proved positive (50%), 9 had isolated calf vein thrombosis (60%). In 5 patients, the color Doppler ultrasound of the calf was considered inconclusive. Overall sensitivity was 53%, specificity 100%, positive predictive value 100%, and negative predictive value 68%. In the femoropopliteal system, sensitivity was 83% and specificity 100%. Considering all patients, sensitivity in the calf system was 40%. Excluding the 5 patients who were difficult to assess, sensitivity increased to 60%. In conclusion, color Doppler ultrasound is not as sensitive as venography in dealing with patients with clinical suspicion of pulmonary embolism, due to its low sensitivity in the calf system when distal thrombi need to be excluded. However, a reasonable alternative is to begin by performing a compression ultrasonography of the femoropopliteal system. Color Doppler ultrasonography of the calf system represents a rarely sensitive and arduous task and does not seem justifiable in this type of patient. Even if deep calf veins are examined, a negative sonogram does not exclude thrombi in this region and venography should be performed if the clinician needs to prove their absence.

Occluded peripheral arteries: clinical utility of argon laser recanalization.

Optically diverged direct argon laser light energy was used prior to conventional balloon angioplasty to recanalize 30 occluded peripheral arteries in 26 patients. Three of five (60%) iliac and 22 of 25 (88%) femoropopliteal lesions ranging in length from 1 to 47 cm (mean, 17.3 cm) were successfully treated, for an overall technical success rate of 83%. In the femoropopliteal system, 13 of 14 (93%) procedures in lesions less than 20 cm and nine of 11 (82%) procedures in lesions greater than 20 cm were treated successfully. No statistically significant differences in success rate based on lesion site, lesion length, degree of lesion calcification, or severity of peripheral vascular disease were found. Major complications were a laser perforation resulting in treatment failure in one case (3%) and a successfully treated distal embolus in another (3%). No reocclusions occurred in the immediate postoperative period. While long-term follow-up will be required to assess continued patency, this system can potentially increase the number of patients amenable to conventional balloon angioplasty and is currently advocated as an alternative to amputation in patients in whom surgical bypass grafting is contraindicated or unfeasible.

The place of abdominal aortography in abdominal aortic aneurysm resection.

We analyzed 110 patients who underwent abdominal aortography as a routine preliminary to abdominal aortic aneurysm resection. In 11 of the 15 patients for whom the procedures were useful in planning the operative tactics, the aortograms would have been performed anyway on clinical indications. In two patients, the changes in surgical maneuvers would not have been made through anatomic inspection at the time of the operations, but the lesions were asymptomatic. Biplane views and views of the femoropopliteal systems were rarely influential. Morbidity from the angiography was minimal and mortality was zero, but about seven aortograms were performed for each one that effected a change in procedure. We concluded that abdominal aortography as a preliminary to aneurysmectomy could be reasonably limited to patients in whom it was indicated by clinical features, including important hypertension, impaired renal function, diminished or absent femoral pulses, suspected mesenteric ischemia, suspected suprarenal extension of the aneurysm, or suspected (from the chest roentgenograms) thoracic aneurysm.

Biplane translumbar aortography for evaluation of peripheral vascular disease

Complete evaluation of the aortoiliac femoropopliteal system is necessary for the proper evaluation of lower extremity peripheral vascular ischemic disease. We have used a modified infrarenal translumbar approach since it is both safely and rapidly performed. An analysis of 212 consecutive cases (the last 182 with translumbar technic) revealed that 72 per cent of patients had significant atherosclerotic involvement of the aorta or one or more common or external iliac arteries, 43 per cent had significant bilateral involvement, and it was judged that retrograde femoral catheterization would have been difficult or impossible in 38 per cent. Biplane aortoiliac evaluation was added in our last seventy-nine studies. This provided additional diagnostic help in thirty-six of these cases and revealed an abnormality not otherwise visible in six of these patients. There were no serious complications in this series.

The use of the cephalic and basilic veins as peripheral vascular grafts.

Obliterative disease of the femoropopliteal system has provided a continuing challenge to vascular surge&amp;#x006f;&amp;#x030a;ns since dos Santos introduced thrombendarterectomy in 1946. Since then, many and varied techniques have been employed with varying degrees of success. We have utilized the reversed long saphenous vein to carry out bypass surgery in the majority of patients suffering from obliterative disease of the femoropopliteal system. However, over the past two years six such cases have presented in which this vein was either unsuitable or unavailable for use, and in these patients we have used the cephalic or the basilic vein to bypass the obstruction. This paper reports the clinical use of these arm veins and the results of investigations into the adequacy of their length, calibre and resistance to arterial pressure.

Late complications from plastic replacement of aortic abdominal aneurysms.

DEFINITIVE therapy of aneurysms of the abdominal aorta began to reach a satisfactory state with the development of the freeze-dried aortic homograft. Aside from the nuisance caused by the difficulties in obtaining these grafts, late complications have occurred at a high rate. These include atheroarteriosclerotic changes, thromboses, aneurysmal dilation with threat of rupture, and late infection. Complications due to the homograft appeared more frequently in the femoropopliteal system than in the aorta. Barner and DeWeese, 1 reviewing aneurysmal degeneration of arterial homografts, felt that the reason for this divergence in behavior between the aortic and femoral popliteal systems was due to the fact that the media of the aorta was 70% to 80% elastin, whereas the femoropopliteal segment had 1% to 5% elastin in the media and 10% to 30% elastin in the adventitia. They conclude that if aneurysmal degeneration develops, the graft should be resected and replaced with

Autogenous Vein Grafts for Femoropopliteal Occlusion

Experience during the past decade has led to considerable agreement concerning the proper operative indications and optimal methods of surgical repair of peripheral arterial occlusions. Although some details remain unsettled, the body of accumulated experimental and clinical evidence has led to the concept that autogenous tissues are more suitable than are synthetic materials for vascular repair wherever possible. While synthetic-tube grafts are mandatory for certain vascular replacements, such as abdominal aneurysms, they should be avoided in favor of either thromboendarterectomy or autogenous vein grafts¹or combinations for repairs of the femoropopliteal system. Acceptable experience has now been reported by a number of different surgeons and the continued longterm-patency rate of autogenous vein grafts has proved to be relatively good even in the face of slow continuation of degenerative disease of the peripheral artery which has been repaired.² <h3>Surgical Indications</h3> Recommendation for surgical repair of the femoropopliteal arterial system

SIGNIFICANCE OF KNEE SKIN TEMPERATURE IN ISCHEMIC LEGS.

IF THE FEMORAL pulse is diminished or absent in a clinically ischemic leg, the informed physician properly suspects that he may be dealing with a surgically correctable problem, since in such cases the obstructing lesion may be limited to the aorto-iliac or iliofemoral areas. However, patients with clinical evidence of arterial insufficiency of the leg are frequently found to have normal femoral and absent popliteal pulsation in that limb. In these cases obstruction may exist in the superficial femoral artery (low, high, or total), the popliteal artery (low, high, or total) or the entire femoropopliteal system. 1 Knowledge of the level and/or the extent of the block in such patients is important, since the lesions which are higher may be amenable to surgery while those which involve the distal popliteal artery are usually difficult to cure surgically. It is the purpose of this communication to report observations which indicate

Extensive Aortic-Iliac-Femoral Grafting

There are many reports of grafts from the aorta to the femoral vessels in the thighs, and we have used this graft several times where anastomosis to the iliac vessels within the abdomen was impossible or appeared likely to become thrombosed. Unilateral extension of a bifurcation graft down to the popliteal artery has been reported by Crawford, Creech, Cooley, and De Bakey1; by Linton and Menendez,5the latter reporting healing of a shin ulcer after grafting, and by Laufman, Hohf, Bernhard, and Trippel.4The problems connected with graft replacement of the distal aorta and the femoropopliteal system simultaneously prompt this discussion of experience, since further need for such a procedure will undoubtedly occur. Report of Cases Case 1. —A 47-year-old white man had been followed for several years elsewhere because of peripheral vascular disease, for which a bilateral lumbar sympathectomy had been performed in 1950, with a

Study of elasticized dacron as arterial prosthesis; experimental comparison with other plastics, homologous arteries, and autogenous veins.

Despite the widespread development of peripheral vascular shunt grafting for atherosclerosis of the femoropopliteal system, there is still no general agreement as to the best replacement material. Early enthusiasm for homologous arterial replacement appears to be waning as reports of degenerative changes in these grafts increase. 10,41 Difficulties in procurement of large numbers of arterial homografts have also proved to be a disadvantage as increasing numbers of patients seek operation. Autogenous vein grafts for peripheral vascular shunts have not developed wide surgical popularity, although recently there appears to be increasing approval of this material. The reluctant acceptance of veins may be due to the somewhat more difficult technique associated with their use and to some misunderstanding of the incidence of aneurysmal dilatation. This appears to be minimal when small peripheral veins are used as vascular replacements. 23 Aortic largevessel replacement often results in aneurysm formation. A large number of synthetic