EVERSION ENDARTERECTOMY: A NEW APPLICATION OF AN OLD TECHNIQUE

Restoration of arterial flow to a severely ischemic extremity remains a major challenge in vascular surgery. The procedure of choice for limb salvage is a bypass utilizing reversed saphenous vein. When the saphenous vein is unsuitable or unavailable, the surgeon must turn to endarterectomy of the femoral and popliteal systems or synthetic, composite, heterologous, autologous, or homologous grafts. To avoid the problems associated with these techniques and to improve the results of limb salvage, we have revived and modified the technique of superficial femoral artery eversion endarterectomy and combined it with other reconstructive techniques in an effort to salvage the severely ischemic lower extremity. Of 38 patients treated for incapacitating claudication or severe limb ischemia during a one-year period, six patients had an unsuitable saphenous vein for the proposed reconstruction. Five of these patients underwent superficial femoral eversion endarterectomy. These six patients have 100% patency at follow-up seven months to one year postoperatively. Our experience with these six patients, including angiographic follow-up, will be presented.     

Arterial reconstruction using the basilic vein from the zone of injury in pediatric supracondylar humeral fractures: a clinical and radiological series

The authors describe the advantages of using the basilic vein as an arterial conduit in the management of children with supracondylar humeral fractures requiring vascular repair. Eight children, aged 3 to 10 years, presented with supracondylar humeral fractures and vascular injury. In all eight children, the arteries were successfully reconstructed with a reversed, interposition basilic vein graft harvested from the ipsilateral arm. The basilic vein was anatomically consistent with few side branches and was an excellent size match for the brachial artery. There were no postoperative thromboses. At a minimum follow-up of 1 year, all children had palpable radial pulses and the vein grafts were patent with no anastomotic or other focal stenoses. This series confirms the safety of using a donor vein from within the zone of injury for arterial reconstruction, after a supracondylar humeral fracture. Benefits include a single surgical wound on the less conspicuous medial side of the arm, reduced operating time, and preservation of donor veins that may be subsequently required for the management of atherosclerotic disease.     

Functional comparison of the human isolated femoral artery, internal mammary artery, gastroepiploic artery, and saphenous vein

Human femoral, internal mammary, and gastroepiploic arteries and saphenous veins are used as bypass grafts for coronary surgery or for reconstruction in arterial occlusive disease. We have characterized the contractile responses of these vessels to various agents that are liberated during cardiac or vascular surgery. In organ baths, U46619 (a stable thromboxane A2 mimetic), norepinephrine, endothelin-1, angiotensin II, and KCl caused concentration-dependent contractions in all vessels tested. Leukotriene C4 did not induce any contraction in the arteries, whereas a contraction was obtained in the saphenous vein rings. U46619 induced the most powerful contraction in all vessels tested. The pD2 values for each agent did not differ among the different vessels. When responses were expressed as a percentage of KCl-induced contraction, the contraction of endothelin-1 (151+/-5%) and leukotriene C4 (43+/-5%) was more significant on saphenous veins than on arteries. In conclusion, thromboxane A2 appears to be the most potent endogenous constricting agent on different human vascular beds. Our second finding is that saphenous veins are more sensitive to contract to leukotriene C4 and endothelin-1 than arteries. These properties may influence early and (or) long-term vein graft patency.     

Recurrent myocardial infarction in a patient with Prinzmetal's angina and normal coronary arteries

A 55-year-old man was referred for the evaluation of frequent chest pain and syncope. While in the hospital, he experienced severe chest pain accompanied by transient ST segment elevation and a slight elevation of cardiac enzyme levels. Multiple coronary arteriograms were recorded at various times during an interval of 2 months. On one occasion, the results were normal; on another occasion, they showed total occlusion of the left anterior descending, diagonal, and circumflex coronary arteries. The occlusion was completely relieved with sublingual nitroglycerin. Because the patient's clinical condition deteriorated rapidly, double aortocoronary saphenous vein bypass was performed to the left anterior descending and circumflex coronary arteries. During the induction of anesthesia, ventricular fibrillation occurred, and the patient died from refractory recurrent fibrillation 4 hours after surgery. Postmortem examination revealed normal coronary arteries, patent vein grafts, and multiple focal areas of recent and old myocardial fibrosis. Thus, it appears that coronary spasm, in the presence of otherwise normal coronary arteries, can produce myocardial infarction with necrosis, and that medical management may provide a more successful method of treating such patients.     

Functional properties of fresh and cryopreserved carotid and femoral arteries,and of venous and synthetic grafts: comparison with arteries from normotensive and hypertensive patients

The ideal arterial graft must share identical functional properties with the host artery. Surgical reconstruction of the common carotid artery (CA) is performed in several clinical situations, using expanded polytetrafluoroethylene prosthesis (ePTFE) or saphenous vein (SV) grafts. At date there is interest in obtaining an arterial graft that improves the results of that nowadays available. The use of a fresh or cryopreserved/defrosted artery appears as an interesting alternative. However, if the fresh and cryopreserved/defrosted arteries allow an adequate viscoelastic and functional matching with the host arteries needs to be established. The aims were to compare the viscoelastic and functional performance of: (1) conduits used in CA reconstruction (SV and ePTFE) with those of the fresh and cryopreserved/defrosted CA and femoral arteries (FA), and (2) normotensive and hypertensive patients’ arteries with those of the arterial substitutes in vitro analyzed. Pressure, diameter and wall thickness of the CA were recorded in 15 normotensive and 15 hypertensive patients (in vivo studies), and in SV, fresh and cryopreserved/defrosted CA and FA (obtained from 15 donors), and ePTFE segments (in vitro studies). From stress–strain relationship we calculated elastic and viscous modulus, and the characteristic impedance. The local buffer and conduit functions were quantified as the viscous/elastic quotient and the inverse of the characteristic impedance. Fresh and cryopreserved/defrosted CA and FA were more alike, both in viscoelastic and functional levels, respect to normotensive and hypertensive patients’ arteries, than the ePTFE and SV grafts. CA and FA cryografts could be considered an important alternative for carotid reconstruction.     

The geometry of unstented and stented pig common carotid artery bypass grafts

The long-term success of arterial bypass grafting with autologous saphenous veins is limited by neointimal hyperplasia (NIH), which seemingly develops preferentially at sites where hydrodynamic wall shear is low. Placement of a loose-fitting, porous stent around end-to-end, or end-to-side, autologous saphenous vein grafts on the porcine common carotid artery has been found significantly to reduce NIH, but the mechanism is unclear. In a preliminary study, we implanted autologous saphenous vein grafts bilaterally on the common carotid arteries of pigs, placing a stent around one graft and leaving the contralateral graft unstented. At sacrifice 1 month post implantation, the grafts were pressure fixed in situ and resin casts were made. Unstented graft geometry was highly irregular, with non-uniform dilatation, substantial axial lengthening, curvature, kinking, and possible long-pitch helical distortion. In contrast, stented grafts showed no major dilatation, lengthening or curvature, but there was commonly fine corrugation, occasional slight kinking or narrowing of segments, and possible long-pitch helical distortion. Axial growth of grafts against effectively tethered anastomoses could account for these changes. CFD studies are planned, using 3D MR reconstructions, on the effects of graft geometry on the flow. Abnormality of the flow could favour the development of vascular pathology, including NIH.     

Femoral Tibial Bypass Grafts: The Alternative to Amputation

Severe ischemia and distal gangrene of lower extremities due to obstruction of the popliteal artery and its branches need not require major amputation. Autogenous vein grafts to the distal anterior tibial, posterior tibial, peroneal and dorsalis pedis arteries can avoid tissue loss in many instances.     

Can markers injected into a single-loop anterior cruciate ligament graft define the axes of the tibial and femoral tunnels? A cadaveric study using roentgen stereophotogrammetric analysis

Lengthening of a soft-tissue anterior cruciate ligament (ACL) graft construct over time, which leads to an increase in anterior laxity following ACL reconstruction, can result from relative motions between the graft and fixation devices and between the fixation devices and bone. To determine these relative motions using Roentgen stereophotogrammetry (RSA), it is first necessary to identify the axes of the tibial and femoral tunnels. The purpose of this in vitro study was to determine the error in using markers injected into the portions of a soft-tissue tendon graft enclosed within the tibial and femoral tunnels to define the axes of these tunnels. Markers were injected into the tibia, femur, and graft in six cadaveric legs the knees of which were reconstructed with single-loop tibialis grafts. The axes of the tunnels were defined by marker pairs that were injected into the bones on lines parallel to the walls of the tibial and femoral tunnels (i.e., standard). By using marker pairs injected into the portions of the graft enclosed within the tibial and femoral tunnels and the marker pairs aligned with the tunnel axes, the directions of vectors were determined by using RSA, while a 150 N anterior force was transmitted at the knee. The average and standard deviations of the angle between the two vectors were 5.5+/-3.3 deg. This angle translates into an average error and standard deviation of the error in lengthening quantities (i.e., relative motions along the tunnel axes) at the sites of fixation of (0.6+/-0.8)%. Identifying the axes of the tunnels by using marker pairs in the graft rather than marker pairs in the walls of the tunnels will shorten the surgical procedure by eliminating the specialized tools and time required to insert marker pairs in the tunnel walls and will simplify the data analysis in in vivo studies.     

Experience of vein grafting in G?ttingen minipigs.

We experimented with vein grafting surgery on G?ttingen minipigs. Using the internal jugular vein for the tissue graft, we performed side-to-side anastomosis to the carotid artery, to which it runs parallel. One key point in this surgery was to prevent vasospasm of the carotid artery so as to keep the lumen sufficiently patent during anastomosis. The histopathological findings in the grafts which remained patent resembled those of vein grafts in humans. We therefore considered that this technique in minipigs can be applied for the study of coronary artery bypass surgery in humans.     

INSERTION OF AN INTRAAORTIC BALLOON THROUGH A LIMB OF AN AORTOFEMORAL GRAFT AFTER AORTIC VALVE REPLACEMENT, DOUBLE CORONARY ARTERY BYPASS, AND RESECTION OF AN ABDOMINAL AORTIC ANEURYSM

This case report describes a useful and unusual route for insertion of an intraaortic balloon in 63-year-old man who was operated upon for calcific aortic stenosis, coronary atherosclerosis involving the left anterior descending and right coronary arteries, and a large abdominal aortic aneurysm. Aortic valve replacement was accomplished with a porcine heterograft prosthesis. Bypasses to the left anterior descending and right coronary arteries were constructed with reversed saphenous vein grafts, and the abdominal aneurysm was resected and repaired with a bifurcated woven Dacron vascular graft. An electively placed intraaortic balloon was inserted through the right limb of the aortic graft prosthesis and used to assist the patient during the immediate postoperative period. Uneventful recovery ensued.     

Prolonged systemic delivery of tirofiban in a thrombus-laden saphenous vein graft

Results from previous trials have shown conflicting results from local delivery of thrombolytic agents to diminish thrombus burden before intervention in native coronary arteries and saphenous vein grafts. We described a patient with an acute coronary syndrome who was treated for 24 hours with systemic tirofiban (Aggrastat), a glycoprotein IIb/IIIa inhibitor, for the treatment of a degenerated saphenous vein graft with a TIMI grade 4 thrombus (large-sized thrombus). Angiographic evaluation 48 hours later revealed complete resolution of the thrombus with normal coronary blood flow.     

A novel alternative placement site and technique for totally implantable vascular access ports in non‐human primates

Background Two novel approaches to implanting a central venous catheter port in non‐human primates (NHPs) using peripheral insertion are presented and compared. Methods Sixty vascular access port (VAP) implants were attempted in 52 NHPs by saphenous vein puncture (n = 20) or saphenous vein cutdown (n = 40). Results Fifty eight procedures were successful. Eighteen of 20 VAPs were successfully placed using saphenous vein puncture, and 40 of 40 using saphenous vein cutdown. There were no significant differences between procedures. Mean implantation times were similar between groups. At explant or study endpoint, all 58 VAPs were patent. Conclusions Vascular access port implantation by saphenous vein puncture or saphenous vein cutdown is safe and effective in NHPs. It is less invasive than conventional procedures, has fewer complications, provides outstanding patency, and reduces surgery time. Furthermore, it allows for cooperative in‐homecage VAP use, minimizing handling stress. We recommend these refined methods for long‐term vascular access in NHPs.     

Influence of smoking and plasma factors on patency of femoropopliteal vein grafts.

OBJECTIVE--To determine the effects of smoking, plasma lipids, lipoproteins, apolipoproteins, and fibrinogen on the patency of saphenous vein femoropopliteal bypass grafts at one year. DESIGN--Prospective study of patients with saphenous vein femoropopliteal bypass grafts entered into a multicentre trial. SETTING--Surgical wards, outpatient clinics, and home visits coordinated by two tertiary referral centres in London and Birmingham. PATIENTS--157 Patients (mean age 66.6 (SD 8.2) years), 113 with patent grafts and 44 with occluded grafts one year after bypass. MAIN OUTCOME MEASURE--Cumulative percentage patency at one year. RESULTS--Markers for smoking (blood carboxyhaemoglobin concentration (p less than 0.05) and plasma thiocyanate concentration (p less than 0.01) and plasma concentrations of fibrinogen (p less than 0.001) and apolipoproteins AI (p less than 0.04) and (a) (p less than 0.05) were significantly higher in patients with occluded grafts. Serum cholesterol concentrations were significantly higher in patients with grafts that remained patent one year after bypass (p less than 0.005). Analysis of the smoking markers indicated that a quarter of patients (40) were untruthful in their claims to have stopped smoking. Based on smoking markers, patency of grafts in smokers was significantly lower at one year by life table analysis than in non-smokers (63% v 84%, p less than 0.02). Patency was significantly higher by life table analysis in patients with a plasma fibrinogen concentration below the median than in those with a concentration above (90% v 57%, p less than 0.0002). Surprisingly, increased plasma low density lipoprotein cholesterol concentration was significantly associated with improved patency at one year (85%) at values above the median compared with patency (only 68%) at values in the lower half of the range (p less than 0.02). CONCLUSIONS--Plasma fibrinogen concentration was the most important variable predicting graft occlusion, followed by smoking markers. A more forceful approach is needed to stop patients smoking; therapeutic measures to improve patency of vein grafts should focus on decreasing plasma fibrinogen concentration rather than serum cholesterol concentration.     

Venous smooth muscle contains vasoconstrictor ETB-like receptors.

Two endothelin (ET) receptor subtypes have been identified to date: the ETA receptor which preferentially binds ET-1 over ET-3, and the ETB receptor which is non-selective. This study characterized the ET receptor subtypes present in several vascular smooth muscle preparations using standard in vitro techniques. In all but one of the arteries tested, ET-3 was significantly less potent than ET-1. In contrast, the potency of ET-3 was very similar to that of ET-1 in all of the veins. The selective ETA receptor antagonist BQ-123 blunted the ET-1 contractions in rabbit carotid artery, but not in saphenous vein. The selective ETB receptor ligand sarafotoxin S6c contracted the rabbit saphenous vein, but not the carotid artery. These data suggest that vascular smooth muscle cells express ETA and ETB receptors. Stimulation of either receptor subtype can result in force development.     

Reverse anterior tibial artery flap for reconstruction of foot donor site

The foot offers numerous useful options for hand reconstruction. Hallux transfer, dorsalis pedis flap, second toe transfers, and toe joint transfers offer good functional results in reconstructed hands. However, when the donor site is repaired with skin grafts, delayed wound healing, scarring, and contractures often result. Poor cosmesis of the donor site and altered gait are the main drawbacks of the procedures. The authors propose a new concept of primary reconstruction of the donor foot using a reverse-flow anterior tibial flap from the same leg. Two flaps are raised from the same anterior tibial vessel system in continuity as a distal free flap for hand reconstruction and as a proximal reverse-flow pedicled flap to resurface the donor defect. This technique allows good flap reconstruction of the foot donor site, reducing morbidity and limiting the operation to the same limb. The authors report their experience of 33 cases. There were no failures. Primary wound healing was achieved in the foot donor site, with acceptable cosmesis and satisfactory function.     

Reconstruction of rat femoral veins with microvascular prostheses

Synthetic conduits have not been suitable for microvascular reconstruction owing primarily to their high thrombogenicity. Vein replacements are the most vulnerable to thrombosis because of their low shear rates and low pressure. Experimental replacement of microvenous segments with prosthetic segments has shown little success. Recent technological advances in biomaterials and control of thrombogenesis provide the potential for success in the development of venous prostheses. The purpose of this study was to assess the use of nonbiodegradable composite polyurethane microvascular prostheses for reconstruction of rat femoral veins. Rat femoral venous defects of 10 mm were reconstructed with autogenous vein (n = 12), unprocessed plain polyurethane (n = 5), and nonbiodegradable composite polyurethane (n = 31). Patency was evaluated by direct observation and proximal venous milking tests. The patency rate of composite grafts was not significantly different from that of isotopic vein (p = 0.5, Fisher's exact test), and both had higher patency than unprocessed polyurethane (p less than 0.01). Composite grafts were examined sequentially using light and scanning electron microscopy. Grafts were fully endothelialized between the first and third months. The neointimal, neomedial, and neoadventitial layers could be seen more distinctly over time. New opportunities in reconstructive microsurgery may be opened by microvascular prostheses that are complaint and thromboresistant.     

Embolic protection: limitations of current technology and novel concepts

Distal embolic event is one of the major limitations of coronary and non-coronary vascular interventions. Balloon and filter-based Embolic Protection Devices (EPDs) are a new class of interventional devices, used to prevent consequential morbidity and mortality of the distal embolic events. Data from first generation EPD supply proof of concept and show approximately 40% reduction in mortality and morbidity, when EPDs are used during saphenous vein grafts (SVGs) interventions. Current limitations of all first generation EPD technology taper their penetration. With breakthroughs in embolic protection technology, it is estimated that, in the near future, EPDs will be used with stenting in all high-risk lesions (SVGs, carotid arteries and acute coronary syndromes), become the standard of care and even be used in low risk cases.     

The effects of femoral graft placement on in vivo knee kinematics after anterior cruciate ligament reconstruction

Achieving anatomical graft placement remains a concern in Anterior Cruciate Ligament (ACL) reconstruction. The purpose of this study was to quantify the effect of femoral graft placement on the ability of ACL reconstruction to restore normal knee kinematics under in vivo loading conditions. Two different groups of patients were studied: one in which the femoral tunnel was placed near the anterior and proximal border of the ACL (anteroproximal group, n=12) and another where the femoral tunnel was placed near the center of the ACL (anatomic group, n=10) MR imaging and biplanar fluoroscopy were used to measure in vivo kinematics in these patients during a quasi-static lunge. Patients with anteroproximal graft placement had up to 3.4mm more anterior tibial translation, 1.1mm more medial tibial translation and 3.7° more internal tibial rotation compared to the contralateral side. Patients with anatomic graft placement had motion that more closely replicated that of the intact knee, with anterior tibial translation within 0.8mm, medial tibial translation within 0.5mm, and internal tibial rotation within 1°. Grafts placed anteroproximally on the femur likely provide insufficient restraint to these motions due to a more vertical orientation. Anatomical femoral placement of the graft is more likely to reproduce normal ACL orientation, resulting in a more stable knee. Therefore, achieving anatomical graft placement on the femur is crucial to restoring normal knee function and may decrease the rates of joint degeneration after ACL reconstruction.     

The circulatory system in Phreatoicidea: implications for the isopod ground pattern and peracarid phylogeny

The circulatory systems of four species of Phreatoicidea and two species of Oniscidea were studied on the basis of serial semi-thin sections and a corrosion cast method. A 3D computer reconstruction was used to visualize the circulatory organs in the head of the Phreatoicidea. In the Phreatoicidea, the circulatory system consists of a longitudinal dorsal heart extending from the third thoracic to the border between the fourth and fifth pleonal segments. It is equipped with two pairs of asymmetrically arranged ostia, while five pairs of lateral cardiac arteries and an unpaired anterior aorta extend from the heart. Entering the head, the aorta is accompanied by the two first lateral arteries, which supply the muscles of the mandibles. Four pairs of arteries branch off the aorta to supply both pairs of antennae, the eyes, and sinuses in the head. In addition, several minute capillaries extend from the aorta to supply the brain. The two oniscidean species were re-investigated with regard to some characters which have been controversially discussed. In these species, the heart extends from the border between the fifth and sixth thoracic segments to the fifth pleonal segment. Five pairs of lateral cardiac arteries and the unpaired anterior aorta lead off the heart. A ventral vessel was not observed. The ground pattern of the circulatory system in isopods is reconstructed with greater reliability through optimisation of its characters based on proposed phylogenetic relationships. The results do not support a phylogenetic position of the Isopoda as basal Peracarida or even basal Eumalacostraca.     

Bovine Heterografts for Hemodialysis

Long-term results with 52 bovine, 53 saphenous vein and 78 radial-cephalic arteriovenous fistulas (AVF) were analyzed. Side-to-end radial-cephalic AVF provided the best patency data, and remain the preferred access system for hemodialysis. Bovine AVF were next in ranking with better patency rates than for the saphenous vein AVF studied. Corrected one-year patency rates were 71 percent for bovine, 45 percent for saphenous and 91 percent for radial-cephalic AVF. The incidence of nonthrombotic complications with bovine AVF was higher than with saphenous vein AVF. Distal ischemia due to “steal” and certain bleeding and wound complications were unique to bovine AVF. Excellent dialysis blood flow rates and easy accessibility were provided by bovine grafts. When a satisfactory radial-cephalic AVF cannot be created, bovine graft AVF is an acceptable alternative for hemodialysis access.