Revascularization of cerebral ischemia after previous bilateral extracranial-intracranial bypass procedures.

Extracranial-intracranial (EC-IC) bypass grafting procedures were specially designed for treatment of bilateral internal carotid artery occlusion. When performed in an expeditious manner, EC-IC bypass procedures have produced effective and durable results, despite the recent disfavor given to this procedure. This communication reports a 68-year-old white man who developed generalized cerebral ischemia manifested as confusion, incoherence, disorientation, ataxia, and numerous episodes of syncope daily. A cerebral angiogram revealed bilateral external carotid arteries and left solitary vertebral artery critical stenosis. Transcranial Doppler study demonstrated reduction of cerebral and vertebral-basilar perfusion. However, the patient's EC-IC bypass graft had remained patent since 1985. The patient's recurrent symptoms of global ischemia and syncope resolved after carotid endarterectomy, vein patch external carotid artery, and vertebral-to-common carotid artery transposition. This report reiterates the value of the EC-IC bypass procedure and presents the surgical management of symptomatic external carotid and vertebral artery stenosis in patients after EC-IC bypass procedures.

Comparative results of early and delayed cannulation of arteriovenous graft in haemodialysis.

OBJECTIVE: To determine whether arteriovenous graft (AVG) can be cannulated for haemodialysis 24-48 h following placement. DESIGN AND MATERIALS: Thirty-six upper extremity Gore-Tex PTFE arteriovenous grafts were cannulated for haemiodialysis 24-36 h (n = 18) and at 10-14 days (n = 18) following insertion. The determinant parameters were compression time to control bleeding, venous back pressure, haematoma, infection and occlusion. MAIN RESULTS: In a 40 day follow-up, there were no significant difference in cannulation of AVG at 24-36 h vs. 10-14 days using the predetermined parameters. CONCLUSION: Early graft cannulation produced no adverse results than late cannulation when the diameter of the tunneller matched the diameter of the graft. Early graft cannulation was safe and recommended.

Surgical management of brachioaxillary-subclavian vein occlusion.

OBJECTIVE: The possibility of using RING PTFE graft as venous bypass to preserve arteriovenous graft function and reduce upper extremity swelling. METHODS: Twenty-two patients with stenosis/occlusion of the brachial-axillary-subclavian vein segment in haemodialysis patients (n = 19) and patients with penetration injury (n = 3) who were not candidates for balloon angioplasty were treated with ring PTFE venous bypass in renal patients and jugular to axillary vein transposition for trauma patients and followed for 10-87 months (mean 31) using venography, Doppler analysis and Duplex scanning. RESULTS: There was no death or neurologic deficit resulting from the venous bypass. Resolution of swelling occurred in 8-48 h. 19/22 (86%) of the bypasses and 3/3 transpositions remained patent after a mean follow-up of 31 months (10-87) months. The attrition was due to AV graft occlusion (n = 2) and infection requiring graft removal (n = 1). CONCLUSIONS: Ring PTFE graft is an acceptable venous bypass for brachial-axillary-subclavian stenosis/occlusion to reduce arm swelling and preserve the function of AV grafts in patients with lesions not amendable with balloon angioplasty or thrombolytic therapy. Jugular-axillary transposition is inappropriate for renal patients.

Femoral artery hypoplasia and persistent sciatic artery with blue toe syndrome: a case report, histologic analysis and review of the literature.

When the primitive sciatic artery remains the major artery in the thigh, the superficial femoral artery is usually poorly developed or absent. This abnormal vasculature is ascribed to the persistent embryologic arterial system which can occur unilaterally or bilaterally. Sciatic artery is known to be susceptible to aneurysmal changes. Pulsatile gluteal mass, distal embolization and, lower extremity ischemia in the sitting position are the pathognomonic clinical symptoms. Excision of the sciatic artery combined with femoro-popliteal bypass is the established recommended surgical treatment.

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.

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.

Management of symptomatic bilateral internal carotid artery occlusion and vertebral artery stenosis.

This report presents a patient with bilateral internal carotid occlusion and concomitant vertebral artery stenosis. His lateralized amaurosis fugax, syncopy and partial visual field defect resolved following open external carotid endarterectomy, onlay patch external carotid angioplasty with endarterectomized internal carotid artery and vertebral artery transposition to the common carotid artery.

Surgical correction of recurrent venous ulcer.

Seventy-six limbs from 46 patients with comparable superficial and deep venous valve incompetence underwent surgical correction for recurrent venous ulcers of the leg that were refractory to various modes of nonsurgical and surgical treatments. A follow-up of 10 to 73 months (mean = 37 months), revealed the venous ulcer healed with perforator ligation and saphenous vein stripping in 14 of 33 (44%), stripping plus valvuloplasty 17 of 21 (80%), stripping plus vein transposition 11 of 14 (78%) and stripping plus valve transplantation 6 of 8 (75%). In patients with incompetent deep venous valve and perforators, the disassociation of the superficial from the deep venous system (stripping) plus correction of the deep venous valvular incompetence (valvuloplasty, transposition or valve transplant) produced superior results in the treatment of recurrent venous ulcer when compared to perforator ligation and saphenous vein stripping alone (p less than 0.005). Adjunctive usage of elastic stockings and intermittent compression pneumatic boots in the perioperative period was helpful in controlling leg swelling and promoting wound healing.

Comparison of surgical modalities in the treatment of recurrent venous ulcer.

Recurrent leg ulcer secondary to superficial and deep venous valve incompetence that are refractory to non-surgical treatment can be healed with the following surgical modalities. Perforator ligation and saphenous vein stripping (PLSVS) healed 4/16 (25%) of the ulcer. PLSVS and correction of deep venous valve incompetence healed 14/16 (87.5%) of the ulcer (p less than 0.005). The mean follow-up was 32 months (8-62 mon). This prospective comparison of the 2 surgical treatments (PLSVS versus PLSVS and correction of deep venous valve) demonstrated that disassociation of the superficial from the deep venous system with PLSVS and correction of the deep valve (valvuloplasty, transposition or valve transplant) produced promising results in the treatment of recurrent venous ulcer. Adjunctive usage of elastic stocking and intermittent compression pneumatic boot to reduce swelling in the paraoperative period improved long term result in venous reconstructive surgery.

Simultaneous mesenteric and renal bypass for visceral ischemia and renovascular hypertension.

Severe visceral ischemia and uncontrollable hypertension in a patient with previous aortofemoral and right aortorenal bypasses underwent surgical correction for stenosis of the celiac, superior mesenteric and left renal arteries. A Dacron jump graft from the junction of the aorto-celiac trunk to the superior mesenteric artery artery alleviated the mesenteric ischemia. A nonreversed vein graft connected the side of the Dacron prosthesis to the end of the left renal artery improved the renovascular hypertension. This modified, simple surgical approach, successfully corrected visceral ischemia and renovascular hypertension and avoided using the severely calcified aorta for celiac and mesenteric bypasses.

Biogenesis and etiology of distal anastomotic intimal hyperplasia.

Distal anastomotic intimal hyperplasia (DAIH) is a viable biologic entity composed of a multi-interlamination of cells and extracellular matrix. Cell transformation and orientation characterize the dynamic process of this 80-130 cell structure. Morphologic similarity exists in the cytoarchitecture of DAIH irrespective of the graft material. Compliance mismatch is not a cause of DAIH, but it enhances the formation. The geometry of the unnatural distal end-to-side anastomosis is predisposed to turbulent flow and DAIH formation. Prevention of DAIH is dependent on pharmacologic suppression of subendothelial smooth muscle proliferation and synthesis of extracellular matrix.

Aortobipopliteal bypass via the obturator foramina.

Patients with aortoiliac disease who have successive occlusion of aortofemoral bypass, femoro-femoral bypass, axillo-femoral bypass, and multiple thrombectomies have a very poor prognosis. In these patients, amputation is frequently inevitable and wound healing is often a problem. Aortobipopliteal bypass via the obturator foramina, without disturbing the collateral vessels which are unsuitable for bypass at the groin, is an alternate approach in the management of this type of patient. Three cases have been successfully constructed using dacron (No. 1) or PTFE (No. 2) prostheses with improvement of ankle brachial indices (0.3-0.6). One graft was patent for five years before occlusion of one limb. Two grafts have remained patent since 1983.

Comparative analysis of pseudointima biogenesis in Gelseal coated Dacron knitted graft versus crimped and noncrimped graft.

Twenty-one grafts (knitted crimped, 7; knitted Gelseal, 7; knitted no crimp, 7) of 7 cm long were inserted into 6 month-old mongrel puppies as infrarenal aortic tube grafts and retrieved at two-month intervals. All grafts were perfusion fixed in situ. Ex vivo arteriograms were obtained prior to processing for light (LM) and transmission electron microscopic (TEM) studies of tissue ingrowth into the grafts. All grafts were patent at the time of harvesting. The thickness of pseudointima plateaued at 10 weeks. There was no demonstrable discrepancy in thickness between grafts (cell 72 +/- 13). The luminal cells were modified myofibroblasts that contained short microvilli, gap junctions, myofilament, and incomplete basal laminae. The pseudointima consisted of an interlamination of myofibroblasts alternating with extracellular matrix of collagen and ground substances. It was more cellular near the lumen and more fibrocollagenous near the graft. Myofibroblasts were found near the lumen and fibroblasts near the graft. Macrophages, vasa vasorum, leukocytes and fibroblasts occupied the interstitial space between the graft fibrils. Similar cellular and extracellular composition existed in the three types of grafts. There was no local inflammatory reaction encountered in the Gelseal treated graft. Gelseal, crimped and noncrimped knitted Dacron grafts had pseudointima of comparable architecture, thickness, cellular and noncellular composition. Gelseal did not hinder pseudointima formation or induce local inflammatory reaction.

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.

Adaptability of endothelial orientation to blood flow dynamics--a morphologic analysis.

Vascular endothelium has a certain specificity in its anatomical orientation. The long axis of the endothelial cell and the shingle effect of cell process overlapping is always oriented parallel to the direction of blood flow. To determine whether this specific anatomical orientation would be maintained when the direction of blood flow was altered, twenty ilio-femoral vein segments and twenty vascular patches of carotid artery and jugular vein were studied. Valvulotomised ilio-femoral vein segments (n = 20) were interposed into adjacent arteries in a non-reversed fashion (the direction blood flow is reversed to the cell process overlapping). One centimeter-square carotid artery and jugular vein patches (n = 20) were rotated 90 degrees (endothelial cell orientation is perpendicular to the direction of blood flow). Reversal of endothelial cell overlapping to complement the complete reversal of the direction of blood flow exists in the vein graft through re-endothelialisation and endothelial reorientation. The process of endothelial reversal occurred in stages (endothelial cell process retraction, interdigitation, complete reversal) and was completed within 8-16 days. In the vascular patch, endothelial re-orientation occurred in 8 days through cell re-orientation and replacement. Mitosis was not encountered in either study. This report highlights certain functions and the adaptive capability of endothelial cells to complement the direction of blood flow.

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.