Combined saphenous vein with free flap reconstruction in the treatment of carotid stenosis.

Revascularization for arterial stenosis in varied anatomic sites exposed to therapeutic radiation has been well described. In most circumstances, symptomatic end organ ischemia has been the indication for surgical intervention. We report the case of a patient who had symptomatic carotid stenosis 40 years after having ipsilateral neck dissection with radiation therapy. We did a saphenous vein graft interposition and free flap reconstruction of the overlying damaged skin.

The role of vein patch in distal anastomotic intimal hyperplasia: an histologic characterization.

Comparison of the cumulative patency of four types of Polytetrafluoroethylene (PTFE) grafts with and without a vein patch at the distal anastomosis in one hundred and twenty ilio-femoral by-passes of sixty dogs revealed: (i) Vein patch improved patency in standard PTFE graft 10/16 (62.5%) versus without a vein patch 6/16 (27.5%) (p < 0.1). (ii) The less rigid thin wall PTFE graft did not benefit from vein patching 22/45 (48.8%) versus those without a vein patch 28/45 (62.2%) (p < 0.2). (iii) DAIH was present in all grafts with and without a vein patch and occurred exclusively at the heel and the toe of the graft plus the floor of the host artery three months after implantation. (iv) An organized fibrocellular multilamination characterized the cytoarchitecture of the DAIH. (v) A process of gradual cell transformation and orientation occurred in DAIH that spanned between the graft and the lumen. Vein patch at the distal anastomosis improved the patency of the more rigid standard PTFE grafts, and adversely affected the less rigid thin walled PTFE graft in dogs. The formation and distribution of DAIH was not altered by a vein patch at the distal anastomosis of PTFE grafts.

Asymptomatic carotid stenosis: appropriateness of operative intervention.

The value of carotid artery surgery for symptomatic lesions causing TIA, stroke, or amaurosis fugax has been well documented. The role of prophylactic carotid endarterectomy in the treatment of asymptomatic stenosis remains controversial. Since a completed stroke with cerebral infarction is often the first clinical manifestation of a stenotic carotid artery lesion, an accurate estimate of the relative risk of medical or operative therapy is needed. Current data suggest that severe internal carotid stenosis of > 75% diameter reduction, deep or complex ulcerations, bilateral stenoses, and stenosis with contralateral occlusion represent a cumulative risk of stroke of 5% to 10% per year, often without antecedent TIA. Conversely, mild or moderate stenosis, small ulcers, fibromuscular dysplasia, and congenital kinking or coiling of the internal carotid carry a very low risk of stroke. The combined risk of stroke and death following prophylactic endarterectomy varies widely, with published rates from less than 1% to nearly 10%. The author suggests that carotid endarterectomy is warranted in good-risk patients with the most severe categories of asymptomatic lesions, when the surgeon's combined rates of stroke and death fall with the 1% to 2% range.

Aberrant right subclavian artery aneurysm: an analysis of surgical options.

During evaluation of a man for claudication, abnormal chest roentgenographic results were found. Computed tomography documented a 6.5-cm aneurysm of an aberrant retroesophageal right subclavian artery. Interruption of the right subclavian artery with an end-to-side subclavian-carotid anastomosis was performed via a right supraclavicular incision, followed immediately by left transthoracic interruption of the origin of the right subclavian artery using a heparin-bonded shunt. This approach avoids previously reported embolic complications while preserving brachial blood flow and providing safe access to the aorta.

Technique to prevent aortic anastomotic bleeding and kinking with bifurcated PTFE grafts.

The bifurcated polytetrafluoroethylene (PTFE) graft was introduced for use in aortic reconstructive procedures in 1980. Despite reports showing excellent patency rates and minimal complications, widespread acceptance of this graft has not been optimal. Bleeding from needle holes at the proximal aortic-PTFE anastomosis has caused particular concern. In addition, because the PTFE is comparatively more rigid than the Dacron material it has a tendency to kink or "buckle" anteriorly due to displacement by the oversewn distal aorta. This paper describes the creation of an everted cuff of PTFE bifurcated graft to prevent aortic suture-line bleeding, and stapling of the distal aortic stump to avoid graft displacement and kinking at the bifurcation.

Pseudointima formation in woven and knitted dacron grafts. A comparative ultrastructural analysis.

Twelve specially designed crimped aortobifurcated grafts (aorta, woven 200 porosity; right limb, woven 500 porosity; left limb, knitted 1200 porosity) were implanted into mongrel dogs that were sacrificed at two, six, eight and twelve-month intervals. Pseudointima from the mid portion of each type of graft was studied with light (LM) and transmission electron microscopy (TEM). An ocular micrometer was used to determine the thickness of the pseudointima. A trilaminar cytoarchitecture resembling the wall of a medium-sized artery existed in the pseudointima. This was characterized by an inner cellular layer, outer fibrocollagenous layer, and multi-interlamination of cells and glycosaminoglycan in the middle layer. The cellular inner layer was thickest in the knitted and thinnest in the woven 200 porosity. A zone of acellularity separated the luminal cells from the underlying myoblasts and myofibroblasts. Specificity of varying types of cell distribution occurred in the pseudointima. Myoblasts and myofibroblasts were located near the lumen while fibroblasts and mesenchymoid cells were situated near the graft. The luminal cells had the combined features of endothelial cells and myofibroblasts. Collagen and glycosaminoglycans were the dominant extracellular matrix. Despite the difference of fluid permeability in high porosity woven and knitted dacron grafts, the pseudointima was well formed and revealed no striking general cytoarchitectural difference between these two types of grafts.

Vein to caval bypass and insertion of suprarenal cava filter for caval occlusion.

Inferior vena cava occlusion following caval interruption (clip, plication, umbrella) for recurrent pulmonary embolism is not uncommon. Patients who are severely disabled by lower extremity venous hypertension following caval occlusion should be considered for caval bypass procedure with concomitant Greenfield filter placement. This report details such a case and outlines the management, including coagulopathy workup.

Distal anastomotic intimal hyperplasia: histopathologic character and biogenesis.

Although thrombogenicity of the prosthetic graft, progression of the atherosclerotic disease and distal anastomotic intimal hyperplasia are known etiologic factors of late graft failure, its occurrence is frequently encountered in the late graft occlusion. Forth-two canine PTFE iliofemoral grafts (all with end-to-side distal anastomosis) were studied. Computer digitization revealed that distal anastomotic intimal hyperplasia occurred exclusively at the heel and the toe of the graft and the floor of the host artery. The distal anastomotic intimal hyperplasia was 80-130 cells thick. Light microscopy and transmission electron microscopy revealed a similar architecture of interlamination of cellular elements and extracellular matrix in the hyperplastic cells. Transmission electron microscopy further defined a gradual cell transformation and orientation from the graft to the lumen. The cells near the graft were characterized by a gradual reduction of rough endoplasmic reticulum with a concomitant acquisition of myofilaments, transforming ovoid mesenchymoid cells to slender myofibroblasts. The orientation of cells in distal anastomotic intimal hyperplasia was embodied by random cell distribution at the periphery to a well-organized interlamination of myofibroblasts and extracellular matrix near the lumen. Distal anastomotic intimal hyperplasia is a biologic entity with active cellular and subcellular events. Its biogenesis appears to be influenced by the hemodynamics of blood flow at the distal anastomosis.

Obturator bypass with nonreversed translocated saphenous vein.

Obturator bypasses with nonreversed translocated saphenous veins were performed in two patients with femoral graft infections. There were no deaths, limb loss, or graft occlusions at two and one-half years of follow-up in the first case and one and one-half years of follow-up in the second case. The nonreversed translocated saphenous vein is a versatile graft that allows for extraanatomic autogenous reconstruction in the face of infection. In both cases, small-caliber distal saphenous veins precluded performing reversed saphenous vein grafts.

Distal anastomotic intimal hyperplasia: biogenesis and etiology.

Anastomotic intimal hyperplasia occurred exclusively at the heel and the toe plus the floor of the distal end-to-side anastomosis of canine autologous femoro-femoral bypass (n = 14) and not in the end-to-end carotid or femoral interposition graft (n = 14). The occurrence of anastomotic intimal hyperplasia in the absence of compliance mismatch in an autologous bypass suggests that the geometry of the end-to-side anastomosis is primarily responsible for intimal hyperplasia formation. It is believed that because an end-to-side distal anastomosis is not a natural occurrence it is conductive to turbulent flow. The latter causes endothelial injury which in turn allows platelet growth factor to incite subendothelial myoblasts in extracellular matrix synthesis and intimal hyperplasia formation. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) identify myofibroblasts and fibrocollagenous matrix as the dominant cellular and extracellular substances in anastomotic intimal hyperplasia.

Nonreversed translocated saphenous vein bypass for arterial trauma.

Nonreversed translocated saphenous vein (NTSV) bypasses were performed for 17 acute arterial injuries. The technique involved controlling hemorrhage, inserting indwelling shunts, perfusing the harvested saphenous vein with papaverine solution, placing the vein in a nonreversed orientation over the shunt, performing valvulotomy under arterial pressure with a modified Mills' valvulotome and completing the distal anastomosis just before removing the shunt. Followup ranged from 2 to 36 months. There were no graft occlusions. The advantages of using NTSV graft for reconstruction of arterial injuries include autogenous reconstruction, reduced size discrepancy between graft and artery at both the proximal and distal anastomosis, improved hemodynamics when spasm compromises distal runoff, and increased vein utilization. NTSV provides increased versatility with both large and small vessel trauma and may improve patency rates.

Ruptured abdominal aortic aneurysm presenting as symptomatic inguinal mass: report of six cases.

Six elderly male patients (mean age, 73 years; range, 66 to 78 years) were admitted with groin masses caused by ruptured abdominal aortic aneurysms. A palpable abdominal mass was present in 33%. All patients eventually underwent abdominal aortic aneurysmectomy with a resultant mortality rate of 50%. Delayed diagnosis, preoperative hypotension, advanced age, poor nutritional status, and excessive intraoperative blood loss were factors contributing to this high mortality rate. In this unusual clinical presentation of ruptured abdominal aortic aneurysm, a high index of suspicion by the emergency room staff and prompt surgical intervention are mandatory to improve mortality rates. The anatomy of the retroperitoneal space and the phylogenetic development of a channel between the scrotum and the kidney are important factors in the development of this symptom complex.

Effects of papaverine on smooth muscle cell morphology and vein graft preparation.

Venous injury following mechanical distension and its late sequelae were studied in a canine model. Jugular vein segments distended without and with papaverine (60 mg/100 ml) were compared with nondistended vein segments after they had been placed into the arterial circulation for 1 to 12 months. Arteriography showed no significant statistical discrepancy in luminal diameter of the three vein segments. Complete reendothelialization had occurred in all vein grafts at the time of harvesting. Similar histocytologic features existed in the nondistended segments and in the portion distended with human plasma protein fraction (Plasmanate) plus papaverine (150 to 300 mm Hg). The intimal-medial hyperplasia was characterized by an increase in fibrocellular layers with an elaboration of vasa vasorum. Conversely, collagen and extracellular matrix replaced the myocyte, producing medial fibrosis in vein mechanically distended with Plasmanate alone. Papaverine prevented mechanical stimulation of smooth muscle cells to overproduce extracellular connective tissue elements. Mechanical stretching of intimal and medial myocytes induced fibrogenesis and fibroplasia. Papaverine is useful in vein preparation; it protects the endothelium and smooth muscle cells in the intima and media and prevents leukocyte infiltration and medial fibrosis.

Nonreversed and in situ vein grafts. Clinical and experimental observations.

The in situ saphenous vein (ISSV) graft has shown promise in distal bypass. Although improved patency has been attributed to preservation of vasa vasorum, there is no direct evidence to support this hypothesis. Femorodistal bypass was done in 33 patients using ISSV grafts (21) or nonreversed saphenous vein (NRSV) grafts (12) during an 18-month period. The NRSV were completely removed from the vein bed but were otherwise prepared in an identical fashion to the ISSV. Immediate complications including incomplete valvulotomy (one), intimal laceration (one), persistent AV communication (two), and extrinsic graft compression (one) were identified and corrected. Two grafts of 2.5 mm diameter occluded acutely. There were no deaths. Of 30 patients discharged with a patent graft, there was one late occlusion (ISSV) at 10 months. No difference in patency between ISSV and NRSV grafts was noted during follow-up extending to 24 months. Overall limb salvage was 94%. In a canine model, 60 vein segments were interposed in the carotid artery using in situ, reversed, and nonreversed techniques. Ultrastructural studies 1, 2, 3, and 6 months after implantation reveal no differences in in situ and nonreversed grafts. New vasa vasorum were identified in NRSV within 1 month. Both ISSV and NRSV grafts demonstrate excellent patency and maintenance of smooth muscle cell architecture. Factors including reduced size disparity at the proximal and distal anastomoses, physiologic distension under arterial pressure, careful handling, and meticulous technique appear to be more important than the theoretic advantages of preserving vasa vasorum.

Management of asymptomatic carotid artery stenosis.

No topic in the field of vascular surgery evokes more controversy than the management of the patient with asymptomatic carotid artery stenosis. The fact remains, however, that patients can and do develop stroke without any antecedent TIA, and there is no definite and predictable way to identify the stroke-prone group. Despite considerable differences of opinion in the literature, our evaluation and experience suggest that certain carotid lesions do in fact carry a high risk of stroke without surgical treatment. We continue to recommend prophylactic carotid endarterectomy for selected asymptomatic carotid lesions. A critical review of the published literature reveals that many series which suggest that nonoperative treatment of asymptomatic carotid disease carries a low stroke risk have in fact followed the patients for an inadequate period of time, and frequently do not adequately define the extent of carotid artery disease. It is now clear that studies which use the presence or absence of carotid bruit alone as a marker for subsequent stroke risk, show a relatively low incidence of stroke during brief follow-up periods. If more objective criteria such as non-invasive tests or angiography are used to identify hemodynamically significant stenoses, then the risk of stroke increases with the length of follow-up. The data suggest that high-grade stenoses, particularly preocclusive ones, and deep or compound ulcers have an unfavorable prognosis. The physician who treats patients with asymptomatic carotid stenosis should make every attempt to accurately quantitate the extent of disease. Non-invasive studies, digital subtraction angiography or conventional cerebral arteriography should be performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Linton patch angioplasty. An adjunct to distal bypass with polytetrafluoroethylene grafts.

Expanded polytetrafluoroethylene (PTFE) grafts have shown promise in bypasses to the popliteal and tibial arteries, but a significant incidence of immediate and late graft failure has limited general acceptance. Compliance differences between the PTFE graft and artery may present technical difficulties in small vessel anastomosis, as well as being implicated in late development of intimal hyperplasia. A retrospective study of 68 patients who had bypass to the distal popliteal and tibial arteries using PTFE grafts with adjunctive distal patch angioplasty was undertaken. Operation was done for limb salvage in 85%. Runoff was marginal in 69%. A venous patch was sutured to the distal artery and the PTFE graft was then sutured into an opening in the proximal portion of the patch. There was one early graft occlusion. Cumulative patency was 97% at 1 month, 92% at 3 months, 87% at 6 months, 74% at 12 months, and 65% at 24, 36, and 48 months. A distal autogenous vein patch permits precise suturing of the distal anastomosis and minimizes technical difficulties leading to early graft failure. Improvement of the compliance mismatch of the PTFE graft and artery may impede the unwelcome development of intimal hyperplasia at the distal anastomotic site. The adjunctive use of a distal patch has resulted in excellent immediate graft patency, despite a high incidence of poor run-off and limb salvage situations.

Role of myofibroblasts in pseudointima formation.

Twenty Dacron grafts (10 crimped and 10 noncrimped) were studied with light microscopy, scanning electron microscopy, and transmission electron microscopy (TEM) 1 to 10 months after insertion into the canine thoracoabdominal aorta. Fibroblast-derived pseudointima maintained a smooth luminal lining that approximated the luminal cross-sectional area of the aorta. Turbulent flow at the corrugated surface of crimped grafts was reflected by the nonuniform alignment of the luminal cells. TEM demonstrated that fibroblasts, macrophages, vasa, and nerve fibers had infiltrated the interstices of the grafts. A zone of loose connective tissues and ground substances existed between the graft surface and the pseudointima and occupied the zone between the luminal cells and the body of the pseudointima. The core of the pseudointima consisted of dense fibrous connective tissue elements and myofibroblasts arranged in a laminated pattern. The luminal cells that were seen were myofibroblasts containing microvilli rather than true endothelial cells. A gradual transition of fibroblast to myofibroblast from the graft to the lumen existed. Myofibroblasts with active rough endoplasmic reticula and Golgi complexes were responsible for formation of ground substances and extracellular matrix. Our observation strongly suggests that the cellular lining in healed Dacron prostheses is derived from modified fibroblasts or multipotential cells. These cells have the capability of transforming into endothelioid and myoblastoid cells as dictated by the functional need.

Intimal hyperplasia and neointima: An ultrastructural analysis of thrombosed grafts in humans.

The distal anastomoses of thrombosed saphenous vein (11), bovine (4), Dacron (7), and polytetrafluoroethylene (PTFE) (27) grafts removed en bloc during reoperation or amputation were studied with light microscopy, scanning electron microscopy, and transmission electron microscopy. Analysis of the ultrastructures of the distal anastomostic regions was done to characterize morphogenesis of intimal hyperplasia and neointimal proliferation. Complete reendothelialization occurred in all vein grafts. In bovine heterografts, there were isolated areas of endothelia. Thrombosed PTFE grafts were lined with gelatinous, proteinaceous material with no consistent organized cellular pattern. In contrast, laminated fibrous tissue produced by fibroblasts lined the Dacron grafts. Intimal hyperplasia was found in 6 of 11 vein grafts and in all prosthetic grafts examined. Regardless of the type of graft used, intimal hyperplasia was found predominantly at the heel of the graft and on the floor of the artery. Beneath the endothelia, collagenous ground substance and myofibroblasts mixed with smooth muscle cells were seen, characterized by pyknotic nuclei, reduced cytoplasm/nuclei ratio, and loss of cytoplasmic organelles. Endothelialization occurred exclusively in vein grafts. Prosthetic grafts lacked endothelia, with the neointima consisting of fibroblasts and fibrous matrix. In intimal hyperplasia, two forms of smooth muscle cell pathomorphogenesis were recognized. Formation of myofibroblasts induced medial fibroplasia, whereas degeneration of muscle cells progressed to medial necrosis. Smooth muscle cells seem to play a role not previously recognized in the pathogenesis of graft failure.