Vein Graft Anastomosis Research Articles

Severe Stenosis of Anastomoses by Using the Symmetry Aortic Connector System

The St. Jude Medical Symmetry Aortic Connector System was developed to create the proximal vein graft anastomoses in coronary artery bypass grafting. We describe three symptomatic patients with severe stenosis of the proximal anastomosis several months after using the Symmetry aortic connector system. Intravascular ultrasound study showed anastomotic neointimal hyperplasia.

The Right Internal Thoracic Artery and Right Gastroepiploic Artery: Alternative Sites for Proximal Anastomosis in Patients with Atherosclerotic Calcified Aorta

Atherosclerotic or calcified ascending aorta is an important predictor of adverse cerebrovascular events. Using off-pump coronary artery bypass (OPCAB) with composite and in situ arterial grafting to avoid aortic manipulation and clamping may reduce the risk of stroke related to aortic atheroembolism. When the aorta is calcified and cannot serve as a safe site for proximal anastomosis, this anastomosis can be performed on the proximal segment of the right internal thoracic artery (ITA) and right gastroepiploic artery (RGEA). Four such cases are described. In 2 patients, the proximal right ITA was used as the site for proximal saphenous vein graft (SVG) anastomosis. Chronic obstructive lung disease in one patient and insulin-dependent diabetes in the other precluded performance of OPCAB with bilateral ITA. In addition, positive Allen test precluded performance of composite T-graft with radial artery (RA) on ITA. Both SVGs were anastomosed distally to the posterior descending artery. In 2 other patients, RA was connected end-to-side to the proximal segment of the RGEA. Both of these patients had repeat operations. The distal end of the RGEA was too small, and concerns regarding the future flow to a very large coronary bed precluded its use as an in situ graft. All patients underwent the operative procedures without any neurological or cardiovascular adverse effects, and all are midterm, symptom-free survivors. Postoperative graft patency was confirmed intraoperatively with flow measurements and postoperatively with control angiography or coronary imaging computed tomography. The RITA and proximal RGEA can serve safely as sites for proximal anastomosis in patients with atherosclerotic calcified aorta undergoing OPCAB.

Arterial and venous smooth-muscle cells differ in their responses to antiproliferative drugs

Arteriovenous polytetrafluoroethylene (PTFE) grafts used for hemodialysis often fail as the result of myointimal hyperplasia with vascular smooth-muscle-cell (SMC) proliferation. The stenotic lesions occur primarily at the graft-vein anastomosis and less frequently at the graft-artery anastomosis. To explore the potentials of pharmacologic agents in preventing hemodialysis-graft stenosis, we first examined the susceptibility of venous and aortic SMCs to 3 antiproliferative drugs. Human aortic and saphenous-vein SMCs were cultured in a medium containing insulin, epidermal growth factor, fibroblast growth factor, and fetal bovine serum. Various concentrations of dipyridamole (0-100 microg/mL), paclitaxel (0-100 microg/mL), and tranilast (0-300 microg/mL) were added. After 72 hours, we subjected the cells to a mitochondrial enzymatic (methylthiazoletetrazolium; MTT) assay and a bromodeoxyuridine (BrdU)-incorporation assay as a means of assessing their proliferation. Dipyridamole, paclitaxel, and tranilast each inhibited the proliferation of aortic and venous SMCs in a dose-dependent manner ( P <.0001). Approximately 90% inhibition was achieved at dipyridamole concentrations of 75 microg/mL and greater in both MTT and BrdU assays; paclitaxel and tranilast were less effective. The venous SMCs were substantially more susceptible to inhibition by all 3 drugs than were the aortic SMCs in the MTT assay. The concentrations required to produce 50% inhibition (IC 50 ) in the venous cells were 5.8 microg/mL (11.5 micromol/L), 9.1 microg/mL (10.7 micromol/L), and 37.4 microg/mL (114.3 micromol/L), respectively, for dipyridamole, paclitaxel, and tranilast. These concentrations were approximately 4.2, 5.3, and 3.0 times lower, respectively, than the corresponding IC 50 values for the aortic cells. The differences in IC 50 between the aortic and venous cells for the 3 drugs were less pronounced in the BrdU assay. The results of this study suggest that strategies for the prevention of stenosis should take into account the fact that lesions at venous anastomoses of arteriovenous grafts may respond differently to drugs than do those at arterial anastomoses.

Vettath’s Anastamotic Obturator—Our Experience of 269 Proximal Anastomoses

Background. Coronary artery bypass grafting (CABG) has come full circle-it started as an off-pump affair, then became an on pump one and now we are trying to keep off the pump again. One of the main reasons for this has been the neurological sequelae subsequent to CABG. But neurological problems kept causing concern even in off-pump CABGs (OPCAB). Side clamping the aorta was thought to be the major factor and thus came the concept of ‘no touch proximal anastomoses’ onto the aorta (1). Though a variety of proximal anastamotic devices are available in the market, high cost is a matter of real concern in third world countries like India. Hence, this endeavor of ours to fabricate an anastamotic device of our own—‘the Vettath’s anastamotic obturator’ (VAO) for proximal anastomoses of saphenous vein grafts (SVG) onto the aorta. VAO is a stainless steel rod with three grooves and a guard at the end, which sinks into the aorta, through a punch hole, cordoned off by two wide purse string sutures. Methods. After trials on perfused animal heart models, we started using this device on humans. We have performed 269 proximal anastomoses using the VAO in 177 of our OPCAB patients in the past 1 year (till July 2003). Ninety-five of them had single top ends, 72 had 2 top ends and 10 had 3 top ends onto the aorta. We have used this on disease free islands on four patients with palpable aortic plaques. Initially all anastomoses were of the proximal first type (to ensure that the flow was adequate). Now-a-days, with confidence, distal first anastomoses are being performed. Results. We had no operative mortality in this group. None of our patients needed IABP support. One patient reported back with angina, after 3 months—he was studied and his grafts were found to be patent. All patients, except three, are being followed up till date and they are leading active symptom free and event free lives. Discussion. It is logical to think that avoidance of side clamp on the aorta reduces the risk of neurologic complications. Vettath’s anastamotic obturator is an indigenous, cheap and reusable alternative to the other costlier devices, which serve the same purpose. Though there is a small learning curve, results are gratifying and complications are few.

Flow dynamics of the St Jude Medical Symmetry aortic connector vein graft anastomosis do not contribute to the risk of acute thrombosis

BackgroundThe efficacy of the St Jude Medical Symmetry aortic connector (St Jude Medical, Inc, St Paul, Minn) for coronary artery bypass is currently debated. Potential drawbacks are the biocompatibility of the endoluminal device, the need for graft manipulation during the procedure, and the 90° offset of the vein graft from the ascending aorta, which may induce graft kinking and abnormal fluid dynamics. In this article, a computational approach was designed to investigate the fluid dynamics pattern at the proximal graft. MethodsFour models of hand-sewn anastomoses and two models of automated anastomoses were constructed; a finite volume technique was used to simulate realistic graft fluid dynamics, including aortic compliance and proper aortic and graft flow rates. The anastomosis geometry performance was analyzed by calculating time-averaged wall shear stress and the oscillating shear index at the toe and heel regions of the proximal graft. ResultsTime-averaged wall shear stress was significantly lower in the hand-sewn anastomosis models than in the two models that simulated the use of the aortic connector (0.38 ± 0.07 Pa vs 1.32 ± 0.4 Pa). Higher oscillating shear index values were calculated in the hand-sewn anastomosis models (0.15 ± 0.02 Pa vs 0.06 ± 0.02 Pa). ConclusionsAutomated anastomosis geometry is associated with less critical fluid dynamics than with conventional hand-sewn anastomosis: the shape of the proximal graft induces more physiological wall shear stresses and less oscillating flow, suggesting a lower risk of atherosclerotic plaque and intimal hyperplasia as compared with conventional anastomosis geometry. Therefore, the reported early thrombosis and late failure of the St Jude Medical aortic connector anastomoses are not related to unfavorable fluid dynamics.

Off-pump coronary artery bypass in patients with Takayasu's disease

We report 2 patients with ostial stenoses of coronary arteries and heavy aortic calcification caused by Takayasu's disease in which severe angina was successfully relieved by off-pump coronary artery bypass grafting. In one case, visceral arteries such as the right gastroepiploic artery, the superior mesenteric artery, and the splenic artery were used as proximal blood sources of saphenous vein grafts. In another case, an aortic connector system was employed for proximal anastomoses of saphenous vein grafts. The use of off-pump coronary artery bypass grafting techniques should be considered in surgical coronary revascularization in patients with Takayasu's disease, thus leading to wide-spreading indication for the surgery.

First-year outcomes of beating heart coronary artery bypass grafting using proximal mechanical connectors

Background To determine the extended results of mechanical connectors we compared the 1-year outcomes of patients having beating heart coronary artery bypass surgery with at least one sutured or mechanically connected proximal vein graft anastomosis. Methods From May 2001 to December 2001, 166 patients were identified as having undergone off-pump bypass grafting utilizing at least one St. Jude symmetry aortic connector (St Jude Medical Anastomotic Technology Group, St. Paul, MN). Follow-up for major adverse cardiac events (MACEs), which is defined as cardiac mortality, myocardial infarction, or revascularization of a previous target vessel, was obtained on 162 patients (97.6%). A control group of 159 patients was identified from a cohort of patients having beating heart surgery with one or more sutured proximal vein graft anastomosis in the preceding year. The MACE follow-ups were obtained in 136 patients (85.6%) by direct telephone contact. Results Patients with connectors showed an accelerated number of MACEs beginning approximately 180 days from the time of surgery and stabilizing at approximately 300 days. Logistic regression analysis identified the presence of diabetes as a significant preoperative risk factor predisposing patients to earlier onset of MACEs ( p = 0.03) with an odds ratio of 2.9 (95% confidence interval, 1.1 to 7.6). Insulin dependent diabetics showed no differences between connector and control patients in the frequency or timing of MACEs. Connector patients using oral hypoglycemic agents demonstrated a significant deviation ( p = 0.01) from a similar control population in the prevalence and timing of MACEs. Conclusions Connector patients showed an increased incidence of early MACEs. These events were characterized by an increased requirement for early target vessel revascularization and were predominantly in noninsulin-dependent diabetics.

Fatal complications after use of the symmetry aortic connector in coronary artery bypass surgery

During the last 2 years, 103 aortic saphenous vein graft anastomoses were performed in 68 patients undergoing off-pump coronary artery bypass by using the Symmetry Bypass System Aortic Connector. Of these patients, 2 died during the early postoperative period. In the first patient, after an episode of ventricular fibrillation and closed-chest cardiac massage, the sternum was opened and hemopericardium secondary to leakage of the proximal anastomotic device was found. The second patient died of ascending aortic dissection, the tear of which was likely to have originated from the proximal anastomotic site.

Initial experience with sutureless proximal anastomoses performed with a mechanical connector leading to clampless off-pump coronary artery bypass surgery

Background We report our early experience with the Symmetry Aortic Connector (St. Jude Medical, St. Paul, MN) used for sutureless proximal aortosaphenous vein graft anastomoses without any cross clamp during coronary bypass procedures. Methods Between November 2001 and August 2002, 206 saphenous vein to aorta proximal anastomoses were created in 132 patients using the Symmetry device. All procedures were performed as part of off-pump coronary artery bypass surgery without any aortic clamping. Intraoperative variables and postoperative data were collected and analyzed retrospectively. Results All 206 anastomoses (100%) were successfully completed with the connector. Severe atherosclerotic disease of the aorta was documented in 16 patients (12%). Four anastomoses (2%) required additional suture placement. Predeployment problems occurred with 3 grafts (2.5%) during loading of the connector. Average number of distal bypasses was 3.2 per patient. One patient (0.7%) required reoperation for bleeding from a proximal anastomosis. Six patients (4.5%) had perioperative myocardial infarction documented by electrocardiographic changes. Thirty-day operative mortality was 3% (4 patients). Intraoperative transit time flow measurement was performed in all cases (100%). Postoperative angiography in 43 patients at a median 3 months postoperatively revealed occlusion of 9 of the 81 saphenous vein grafts (11%). Conclusions The initial experience with a proximal saphenous vein graft to aorta anastomosis using the Symmetry connector demonstrates safety and ease of use. There is however some concern with early graft closure. A prospective randomized study is needed to clarify these concerns.

Formation of a stenotic fibrotic membrane at the distal anastomosis of bovine jugular vein grafts (Contegra) after right ventricular outflow tract reconstruction

dental’ endoesophageal intubation or prompt surgical tracheostomy (Floyd type I). Surgical repair or palliation of associated congenital cardiac lesions has been never described in the literature, because most affected patients usually die before any attempt at surgical intervention. This is the first patient to our knowledge to survive palliation of the respiratory tract malformation as well as definitive intracardiac repair. She is now thriving and is currently being evaluated for definitive surgical reconstruction of the airway and alimentary tract. References

Initial results on the use of mechanical devices for proximal saphenous vein graft anastomoses: a clinical and angiographic evaluation

OBJECTIVE: To report on our initial clinical experience of the utilization of a mechanical anastomotic device (MAD) to perform saphenous vein graft to aorta anastomosis. METHOD: Between June 2002 and May 2003, 17 patients, including 13 male, with a mean age of 64.4 ± 9.4 years, were selected for coronary artery bypass grafting using MAD. A total of 49 anastomoses, 19 arterial and 30 vein grafts, were performed with a mean of 2.9 ± 0.5 anastomoses per patient. Eleven (36.7%) vein-graft anastomoses were performed with conventional sutures and 19 (63.3%) using MAD. The clinical evolution, enzymatic and electrocardiographic alterations as well as an angiographic study were analyzed in the postoperative period. RESULTS: Of the 17 patients, the mechanical device was used on 16 (94.1%). Six (37.5%) patients were operated on under cardiopulmonary bypass with a mean time of 102.9 ± 16.9 minutes. The postoperative evolution was satisfactory in all patients. No patient presented with enzymatic, myocardial infarction or other ischemic electrocardiographic alterations in the immediate postoperative period. Early postoperative angiography was performed in 9 (52.9%) patients. The anastomoses of the left internal thoracic artery to left anterior descending artery were patent in all cases. Of the 15 saphenous vein grafts studied, 11 (73.3%) were performed using MAD, 9 (81.8%) of which were patent. All the 4 conventionally sutured vein anastomoses were patent. No hospital deaths occurred. In the late follow-up, 88.2% of the patients were free of cardiac-related events. CONCLUSIONS: MAD for vein graft-to-aorta anastomosis proved to be feasible, but a wider analysis of the benefits of its utilization regarding operative time, aggression to the patient, patency of the grafts and final cost are necessary.

Novel proximal and distal anastomotic devices for coronary artery bypass surgery

THE CURRENT LITERATURE describes many varied experimental and clinical applications of minimally invasive techniques to enhance outcomes after coronary artery bypass grafting (CABG). Many techniques facilitating anastomotic procedures are described, but long-term data supporting improved patency rates, efficiency of surgical technique, and outcomes are limited. The growing need for minimally invasive procedures and means of reducing the complexity of endoscopic suturing will be the impetus that drives the development and implementation of such anastomotic devices. Applications of simultaneous suturing, stapling, clipping, stenting, and sealing devices have provided insight toward the development of clinically acceptable procedures to facilitate positive outcomes in minimally invasive CABG surgery. Proximal anastomotic devices not only decrease operative time but also allow the surgeon to avoid using a partial occlusion clamp on the ascending aorta during CABG.1 Successful reports of an aortic anastomotic device (AAD) for sutureless anastomosis to the proximal aorta of saphenous vein grafts without aortic manipulation2,3 may provide the technologic basis to pursue distal anastomotic devices in coronary surgery. However, applying such techniques to create distal anastomoses may prove more difficult and require development of unique technologies; robotic assistance toward totally endoscopic CABG makes these goals more challenging. The ideal distal anastomotic device would have applicability to all potential conduits with interchangeable proximal/distal order and a safe bailout in the case of device malfunction.4 The ability to decrease operative time, create superb anastomoses without technical imperfection, and improve long-term patency rates lends excitement to the developing frontier of distal anastomotic devices in minimally invasive CABG surgery. The objective of this review is to compare the existing devices and provide a basis for continued development of novel anastomotic devices. The anesthetic implications will be considered.

Distal embolization at the site of a stenotic distal anastomosis of a saphenous vein graft, leading to dye entrapment

This case report describes the entrapment of contrast media after recanalization of a recently occluded saphenous vein graft with balloon predilation, thrombectomy and stent implantation. Recanalization of the respective coronary artery was performed, and the entrapped contrast media within the saphenous vein graft progressed to the left circumflex artery. (Int J Cardiovasc Intervent 2003; 5: 84-87)

Aggressive venous neointimal hyperplasia in a pig model of arteriovenous graft stenosis

Vascular access dysfunction is the most important cause of morbidity and hospitalization in the hemodialysis population in the United States at a cost of well over one billion dollars per annum. Venous neointimal hyperplasia characterized by stenosis and subsequent thrombosis, is the major cause of polytetrafluoroethylene (PTFE) dialysis graft failure. Despite the magnitude of the problem, there are currently no effective therapies for the prevention or treatment of venous neointimal hyperplasia in PTFE dialysis grafts. We believe that this is partly due to the lack of a validated large animal model of arteriovenous stenosis that could be used to test out novel interventions. Seven-centimeter PTFE loop grafts were placed between the femoral artery and vein of domestic pigs. The grafts were removed at 2, 4, 7, 14 and 28 days after surgery and subjected to a detailed histological and immunohistochemical examination. Significant neointimal hyperplasia and venous stenosis developed by 28 days at the graft-vein anastomosis. There was minimal neointimal hyperplasia at the graft-artery anastomosis. Venous neointimal hyperplasia (VNH) was characterized by (a) the presence of smooth muscle cells/myofibroblasts; (b) angiogenesis within both the neointima and adventitia; and (c) the presence of an active macrophage cell layer lining the PTFE graft material. These results are very similar to the human lesion previously described by us in dialysis patients. We have developed and validated a pig model of venous neointimal hyperplasia that is very similar to the human lesion. We believe that this is an ideal model in which to test out novel interventions for the prevention and treatment of clinical hemodialysis vascular access dysfunction.

Assessment of an aortosaphenous vein graft anastomotic device in coronary surgery: Clinical experience and early angiographic results

Background Until now technologic evolution in coronary bypass surgery has focused on extracorporeal circulation, on operation without extracorporeal circulation, and on the exposure of the operative site. Recently a one-shot anastomotic device for the proximal anastomosis in coronary surgery was developed. We investigated whether the use of the aortic connector system (ACS) could facilitate the creation of aortosaphenous vein graft anastomoses in myocardial revascularization. Methods From November 2000, 40 ACS devices were used in 36 consecutive patients (mean age 70.7 ± 8.9 years); 12 patients (33.3%) underwent surgery on pump and 24 patients (66.6%) off pump; 50 distal anastomoses were performed. In all cases the connection with the ascending aorta was created before the distal anastomoses because of the necessity to slide the saphenous vein graft (SVG) over the vein transfer sheath. Intraoperative graft function was tested measuring blood flow by Doppler analysis. Postoperative evaluation of the anastomotic patency was carried out by early angiography in 34 patients (94.7%) but was excluded in 5 patients (5.3%) with extensive extracardiac vascular occlusive disease. Results Of 38 AC (95%) evaluated, 36 (94.7%) functioned properly. The end-to-side proximal anastomosis without aortic clamping is instantaneous, the quality of anastomoses was highly rated, no additional stitches were required, and all coronary arteries could be reached. Intraoperative quantity flow was measured by Doppler analysis and all but one showed good flow. Early postoperative angiography demonstrated good patency of the grafts in all cases but 2 (5.3%). At 1-year follow-up, 1 patient died of stroke; all other patients remained free of symptoms and no reoperation was required. Conclusions The use of ACS makes end-to-side anastomosis rapid, effective, and reproducible while eliminating aortic cross clamping; it opens a new era in beating or nonbeating coronary surgery. Long-term results are mandatory to confirm our favorable preliminary results.

Neointimal hyperplasia rapidly reaches steady state in a novel murine vein graft model

Neointimal hyperplasia remains a principal cause of vein graft failure. Genetic contributions to vein graft neointimal hyperplasia could be well studied in the mouse; however, surgical approaches to vein bypass surgery in the mouse have yet to replicate approaches commonly employed in human patients. Consequently, the goal of this study was to develop a murine interposition vein graft model that reproduces characteristics of human vein graft disease. Using C57BL/6J mice, we excised inferior venae cavae (IVCs) from donor mice and grafted them, with end-to-side anastomosis, into the carotid circulation of recipients. IVC grafts were harvested from 3 to 56 days postoperatively, and analyzed for the development of neointima and media. Thickening of both the vein graft neointima and media progressed rapidly between postoperative weeks 1 and 4, and reached steady state levels by approximately week four, with a graft-wall thickness of 91 +/- 4 microm (14 cell layers), a lumen area of 0.56 mm(2), an average neointima-media ratio of 0.4 to 0.6, and a predominance of alpha-smooth muscle actin-staining cells. Comprising predominately smooth muscle actin-expressing cells, the neointima was 50% thicker in the proximal than in the distal third of the grafts (P <.001), but proximal and distal vein graft anastomoses were widely patent. In syngeneic murine carotid interposition IVC grafts implanted with end-to-side anastomoses, moderate, nonocclusive neointimal hyperplasia reaches steady state after the fourth postoperative week. This neointimal hyperplasia, like that of human grafts, predominates near vein graft anastomoses. This vein graft model should facilitate genetic analyses of the pathogenesis of neointimal hyperplasia.

Cirurgia de revascularização coronariana esquerda sem CEC e sem manuseio da aorta em pacientes acima de 75 anos: análise das mortalidades imediata e a médio prazo e das complicações neurológicas no pós-operatório imediato

INTRODUÇÃO: A circulação extracorpórea (CEC) e o manuseio da aorta ascendente (MAA) estão associados a alta incidência de acidente vascular cerebral (AVC) na cirurgia de revascularização do miocárdio (RM) em pacientes idosos. Esta complicação deve-se, sobretudo, ao MAA, por ocasião do pinçamento e despinçamento, quer para isolamento do coração do circuito de CEC, quer para realização das anastomoses dos enxertos na aorta ascendente. OBJETIVOS: Verificar mortalidades imediata e a médio prazo e a ocorrência de AVC no pós-operatório imediato (POI) em pacientes acima de 75 anos submetidos a cirurgia de revascularização do sistema coronariano esquerdo (SCE), sem CEC e sem MAA. MÉTODO: De janeiro de 2000 a abril de 2002, 40 pacientes acima de 75 anos (média 79,1 anos) foram submetidos a cirurgia de revascularização do SCE, com enxerto de artéria torácica interna esquerda (ATIE) para a artéria descendente anterior (DA), e enxerto(s) de veia safena magna oriundo(s) da ATIE para outro(s) ramo(s) da coronária esquerda (enxerto composto), sem CEC e sem MAA. Houve predominância do sexo masculino (67,5%). Foram realizados 89 enxertos (média 2,22 pontes por paciente), sendo 40 (44,94%) de ATIE e 49 (55,06%) de veia safena. A ocorrência de AVC foi avaliada por exames clínico e neurológico. RESULTADOS: Não foi observada ocorrência de AVC no grupo estudado. Não houve óbitos no POI. CONCLUSÃO: A cirurgia de revascularização do SCE em pacientes acima de 75 anos sem CEC e sem MAA pode ser realizada sistematicamente de modo a evitar a ocorrência de AVC, com baixa mortalidade.

External beam radiation attenuates venous neointimal hyperplasia in a pig model of arteriovenous polytetrafluoroethylene (PTFE) graft stenosis

Purpose : Hemodialysis vascular access dysfunction is an enormous clinical problem that causes great morbidity and costs well over one billion dollars per annum. The vast majority of hemodialysis vascular access dysfunction occurs as a result of venous stenosis and thrombosis at the graft-vein anastomosis. At a cellular level, this venous stenosis is the result of venous neointimal hyperplasia (VNH). There are, unfortunately, no effective therapies for VNH. The purpose of this study was to assess the role of external radiation therapy in preventing VNH and venous stenosis. Methods and Materials : Seven-centimeter polytetrafluoroethylene loop grafts were placed bilaterally between the femoral artery and vein of 12 Yorkshire Cross pigs. One side was treated with a single 16-Gy dose of external beam radiation with a linear accelerator, while the contralateral side served as an internal control. Swine were killed after 28 days, and the grafts were carefully dissected out and removed. Neointimal hyperplasia and luminal stenosis were then assessed morphometrically at the graft-vessel anastomoses. Results : External beam radiation therapy significantly reduced the amount of luminal stenosis at the graft-vein anastomosis, with minimal local and systemic toxicity. Conclusions : External beam radiation therapy could be a useful and clinically relevant local treatment for venous stenosis in polytetrafluoroethylene dialysis grafts.

Prospective, randomized evaluation of a cuffed expanded polytetrafluoroethylene graft for hemodialysis vascular access

Background. A cuffed expanded polytetrafluoroethylene (ePTFE) hemodialysis graft was developed to address the problem of recurrent stenosis at the graft-vein anastomosis. The purpose of this study was to compare graft patency and blood flow rates of cuffed and noncuffed (standard) ePTFE grafts placed for hemodialysis access. Methods. Forty-eight patients were prospectively randomized and followed for up to 24 months after placement of a cuffed or standard ePTFE graft for hemodialysis access. Study end points included time to graft failure and blood flow rates on hemodialysis. Results. Risk factors for graft failure were similar in both groups. However, the overall incidence of graft failure was significantly lower in the cuffed ePTFE graft group (P =.039). Graft patency rates in the cuffed versus standard groups were 64% versus 32% at 12 months (P =.037) and 58% versus 21% at 24 months (P =.0213). No cuffed ePTFE graft failed as a result of venous outflow stenosis. Average graft flow rates were similar when first measured 3 months postoperatively (845 mL/min, cuffed vs 715 mL/min, standard; P =.51) but declined more rapidly in the standard group (12 months, 623 vs 253 mL/min [P =.037]; 24 months, 531 vs 121 mL/min [P =.012]). Conclusions. The cuffed ePTFE graft was associated with increased blood flow rates during hemodialysis and improved graft patency compared with a standard ePTFE graft. Our results suggest a beneficial effect of the cuffed venous geometry for hemodialysis vascular access. (Surgery 2002;132:135-40.)

Angiographic results after the use of a sutureless aortic connector for proximal vein graft anastomoses

The sutureless aortic connector system was recently developed to create anastomoses between the aorta and saphenous vein grafts for coronary artery bypass grafting. Ten consecutive patients scheduled for coronary artery bypass grafting were studied; in each patient one proximal anastomosis was performed using the aortic connector and another was sutured in the conventional manner to serve as the patient‘s own control. One graft in the sutured group had a significant stenosis and one of the grafts in which the aortic connector was used, was occluded. In this limited study the use of the sutureless connector system for proximal anastomosis shows satisfactory early graft patency (90%).