Contemporary Treatment of Popliteal Artery Aneurysms in 14 Countries: A Vascunet Report.

OBJECTIVE: Popliteal artery aneurysm (PAA) is the second most common arterial aneurysm. Vascunet is an international collaboration of vascular registries. The aim was to study treatment and outcomes. METHODS: This was a retrospective analysis of prospectively registered population based data. Fourteen countries contributed data (Australia, Denmark, Finland, France, Hungary, Iceland, Italy, Malta, New Zealand, Norway, Portugal, Serbia, Sweden, and Switzerland). RESULTS: During 2012-2018, data from 10 764 PAA repairs were included. Mean values with between countries ranges in parenthesis are given. The incidence was 10.4 cases/million inhabitants/year (2.4-19.3). The mean age was 71.3 years (66.8-75.3). Most patients, 93.3%, were men and 40.0% were active smokers. The operations were elective in 73.2% (60.0%-85.7%). The mean pre-operative PAA diameter was 32.1 mm (27.3-38.3 mm). Open surgery dominated in both elective (79.5%) and acute (83.2%) cases. A medial surgical approach was used in 77.7%, and posterior in 22.3%. Vein grafts were used in 63.8%. Of the emergency procedures, 91% (n = 2 169, 20.2% of all) were for acute thrombosis and 9% for rupture (n = 236, 2.2% of all). Thrombosis patients had larger aneurysms, mean diameter 35.5 mm, and 46.3% were active smokers. Early amputation and death were higher after acute presentation than after elective surgery (5.0% vs. 0.7%; 1.9% vs. 0.5%). This pattern remained one year after surgery (8.5% vs. 1.0%; 6.1% vs. 1.4%). Elective open compared with endovascular surgery had similar one year amputation rates (1.2% vs. 0.2%; p = .095) but superior patency (84.0% vs. 78.4%; p = .005). Veins had higher patency and lower amputation rates, at one year compared with synthetic grafts (86.8% vs. 72.3%; 1.8% vs. 5.2%; both p < .001). The posterior open approach had a lower amputation rate (0.0% vs. 1.6%, p = .009) than the medial approach. CONCLUSION: Patients presenting with acute ischaemia had high risk of amputation. The frequent use of endovascular repair and prosthetic grafts should be reconsidered based on these results.

Experimental study of femoral vein reconstruction with sugarcane biopolymer tubular graft. / Estudo experimental de reconstrução da veia femoral com enxerto tubular do bipolímero de cana-de-açúcar.

OBJECTIVE: to evaluate, through Doppler flowmetry, venography, histology and clinical evolution, the use of sugarcane biopolymer (BP) tubular grafts in the reconstruction of femoral veins in dogs. METHODS: we submitted eight adult dogs to femoral vein reconstruction, on the left with BP tubular graft and on the right with autologous vein. In the postoperative period, the animals underwent clinical evaluation and femoral vein Doppler flowmetry. After 360 days, we reoperated the dogs and submitted them to femoral vein phlebography with iodinated contrast. We removed the segments of the femoral veins containing the grafts and sent them for histopathological evaluation. RESULTS: the dogs did not present hemorrhage, hematoma, surgical wound infection or operated limb edema. One animal had superficial venous dilatation in the left inguinal region. Phlebography performed 360 days after the first surgery showed that three (37.5%) BP grafts and seven (87.5%) grafts from the control group (C) were patent. In the histopathological evaluation, we found an inflammatory reaction, with neutrophils and lymphocytes on the external surface of both groups. In the intimal layer of the grafts and in the outer layer in the two groups, we observed fibrosis. CONCLUSION: based on the results obtained with the experimental model used, BP presents potential to be used as a tubular graft for venous revascularization. However, new research must be performed to confirm its efficacy in the revascularization of medium and large diameter veins, which could allow its use in clinical practice.

OBJETIVO: avaliar, através de dopplerfluxometria, de venografia, de histologia e de evolução clínica, o uso de enxertos tubulares de biopolímero de cana-de-açúcar (BP) na reconstrução de veias femorais em cães. MÉTODOS: oito cães adultos foram submetidos à reconstrução de veia femoral, à esquerda com enxerto tubular de BP e à direita com veia autóloga. No período pós-operatório, os animais foram submetidos à avaliação clínica e dopplerfluxometria das veias femorais. Após 360 dias, os cães foram reoperados e submetidos à flebografia das veias femorais com contraste iodado. Os segmentos das veias femorais contendo os enxertos foram retirados e enviados para avaliação histopatológica. RESULTADOS: os cães não apresentaram hemorragia, hematoma, infecção da ferida operatória ou edema dos membros operados. Um animal apresentou dilatação venosa superficial na região inguinal esquerda. A flebografia realizada 360 dias após a primeira cirurgia demonstrou que três (37,5%) enxertos de BP e sete (87,5%) do grupo controle (C) estavam pérvios. Na avaliação histopatológica foi encontrada uma reação inflamatória com neutrófilos e linfócitos na superfície externa de ambos os grupos. Na camada íntima de revestimento dos enxertos e na camada externa nos dois grupos, foi encontrada fibrose. CONCLUSÃO: com base nos resultados obtidos com o modelo experimental utilizado, conclui-se que a BP apresenta potencial para ser utilizado como enxerto tubular para revascularização venosa, porém novas pesquisas precisam ser realizadas para confirmar a sua eficácia na revascularização de veias de médio e grande calibre, o que poderia permitir o seu uso na prática clínica.

Doença cística adventicial da artéria poplítea: relato de caso / Adventitial cystic disease of the popliteal artery: case report

A doença cística adventicial da artéria poplítea é uma doença pouco frequente, que deve ser considerada no diagnóstico diferencial de pacientes jovens com claudicação intermitente e sem fatores de risco para doença arterial periférica aterosclerótica. Apresentamos um caso de claudicação intermitente de membros inferiores em paciente masculino de 51 anos no qual essa doença foi diagnosticada. Foi submetido a ressecção do segmento de artéria comprometido e interposição de safena autóloga ipsilateral. Discutimos alternativas diagnósticas e terapêuticas

Adventitial cystic disease of the popliteal artery is an uncommon pathology that should be considered in differential diagnostic of younger patients with intermittent claudication and without risk factors for peripheral atherosclerotic arterial disease. We report the case of a 51 year-old male patient presenting with lower-limb intermittent claudication in whom this pathology was diagnosed and who was treated with segmental arterial resection and autologous saphenous vein interposition. We also discuss diagnostic and therapeutic alternatives

New Regenerative Vascular Grafts for Hemodialysis Access: Evaluation of a Preclinical Animal Model.

The purpose of this study was to evaluate a suitable animal model for the in vivo evaluation of patency and vascular tissue regeneration in small intestinal submucosa (SIS) vascular grafts for hemodialysis access. First, a 4-mm U-shaped SIS vascular graft was implanted between the internal carotid artery (CA) and the external jugular vein (JV) in five sheep and six swine. The U-shape grafts remained functional for 53 ± 4 days in sheep and 32 ± 2 days in swine. The sheep model presented exaggerated inflammation, so the swine model was selected for the in vivo study. Based on these initial results, a 4-mm C-shape SIS vascular graft with SIS circumferential reinforcement was developed to mechanically improve the vascular graft and manage complications identified during surgery in both sheep and swine. The C-shape vascular graft was implanted in a swine model (n = 3) between the CA and JV. GORE-TEX® vascular grafts were used as controls in the contralateral side of the neck. C-shape grafts remained patent for 47 ± 4 days, whereas the GORE-TEX® grafts were patent for 30 ± 15 days. The C-shape vascular graft was easier to handle during surgery, and its circumferential reinforcement improved in vivo patency, avoiding kinks in the graft after implantation. Histological results showed neovascularization and some regeneration with the alignment of endothelial cells in the vascular wall of the grafts. The model developed may be helpful in other research involving in vivo studies of vascular grafts for hemodialysis access.

Estudo experimental de reconstrução da veia femoral com enxerto tubular do bipolímero de cana-de-açúcar / Experimental study of femoral vein reconstruction with sugarcane biopolymer tubular graft

RESUMO Objetivo: avaliar, através de dopplerfluxometria, de venografia, de histologia e de evolução clínica, o uso de enxertos tubulares de biopolímero de cana-de-açúcar (BP) na reconstrução de veias femorais em cães. Métodos: oito cães adultos foram submetidos à reconstrução de veia femoral, à esquerda com enxerto tubular de BP e à direita com veia autóloga. No período pós-operatório, os animais foram submetidos à avaliação clínica e dopplerfluxometria das veias femorais. Após 360 dias, os cães foram reoperados e submetidos à flebografia das veias femorais com contraste iodado. Os segmentos das veias femorais contendo os enxertos foram retirados e enviados para avaliação histopatológica. Resultados: os cães não apresentaram hemorragia, hematoma, infecção da ferida operatória ou edema dos membros operados. Um animal apresentou dilatação venosa superficial na região inguinal esquerda. A flebografia realizada 360 dias após a primeira cirurgia demonstrou que três (37,5%) enxertos de BP e sete (87,5%) do grupo controle (C) estavam pérvios. Na avaliação histopatológica foi encontrada uma reação inflamatória com neutrófilos e linfócitos na superfície externa de ambos os grupos. Na camada íntima de revestimento dos enxertos e na camada externa nos dois grupos, foi encontrada fibrose. Conclusão: com base nos resultados obtidos com o modelo experimental utilizado, conclui-se que a BP apresenta potencial para ser utilizado como enxerto tubular para revascularização venosa, porém novas pesquisas precisam ser realizadas para confirmar a sua eficácia na revascularização de veias de médio e grande calibre, o que poderia permitir o seu uso na prática clínica.

ABSTRACT Objective: to evaluate, through Doppler flowmetry, venography, histology and clinical evolution, the use of sugarcane biopolymer (BP) tubular grafts in the reconstruction of femoral veins in dogs. Methods: we submitted eight adult dogs to femoral vein reconstruction, on the left with BP tubular graft and on the right with autologous vein. In the postoperative period, the animals underwent clinical evaluation and femoral vein Doppler flowmetry. After 360 days, we reoperated the dogs and submitted them to femoral vein phlebography with iodinated contrast. We removed the segments of the femoral veins containing the grafts and sent them for histopathological evaluation. Results: the dogs did not present hemorrhage, hematoma, surgical wound infection or operated limb edema. One animal had superficial venous dilatation in the left inguinal region. Phlebography performed 360 days after the first surgery showed that three (37.5%) BP grafts and seven (87.5%) grafts from the control group (C) were patent. In the histopathological evaluation, we found an inflammatory reaction, with neutrophils and lymphocytes on the external surface of both groups. In the intimal layer of the grafts and in the outer layer in the two groups, we observed fibrosis. Conclusion: based on the results obtained with the experimental model used, BP presents potential to be used as a tubular graft for venous revascularization. However, new research must be performed to confirm its efficacy in the revascularization of medium and large diameter veins, which could allow its use in clinical practice.

Experimental study of histological changes in vascular loops according to the duration of the postoperative period: Application in reconstructive microsurgery.

OBJECTIVES: To analyze the histological changes observed in venous grafts subjected to arterial blood flow as a function of the duration of the postoperative period to optimize their use in free flap reconstructions. METHOD: Twenty-five rats (7 females and 18 males) underwent surgery. Surgeries were performed on one animal per week. Five weeks after the first surgery, the same five animals were subjected to an additional surgery to assess the presence or absence of blood flow through the vascular loop, and samples were collected for histological analysis. This cycle was performed five times. RESULTS: Of the rats euthanized four to five weeks after the first surgery, no blood flow was observed through the graft in 80% of the cases. In the group euthanized three weeks after the first surgery, no blood flow was observed in 20% of the cases. In the groups euthanized one to two weeks after the first surgery, blood flow through the vascular loop was observed in all animals. Moreover, intimal proliferation tended to increase with the duration of the postoperative period. Two weeks after surgery, intimal proliferation increased slightly, whereas strong intimal proliferation was observed in all rats evaluated five weeks after surgery. CONCLUSION: Intimal proliferation was the most significant change noted in venous grafts as a function of the duration of the postoperative period and was directly correlated with graft occlusion. In cases in which vascular loops are required during free flap reconstruction, both procedures should preferably be performed during the same surgery.

Experimental study of histological changes in vascular loops according to the duration of the postoperative period: Application in reconstructive microsurgery

OBJECTIVES: To analyze the histological changes observed in venous grafts subjected to arterial blood flow as a function of the duration of the postoperative period to optimize their use in free flap reconstructions. METHOD: Twenty-five rats (7 females and 18 males) underwent surgery. Surgeries were performed on one animal per week. Five weeks after the first surgery, the same five animals were subjected to an additional surgery to assess the presence or absence of blood flow through the vascular loop, and samples were collected for histological analysis. This cycle was performed five times. RESULTS: Of the rats euthanized four to five weeks after the first surgery, no blood flow was observed through the graft in 80% of the cases. In the group euthanized three weeks after the first surgery, no blood flow was observed in 20% of the cases. In the groups euthanized one to two weeks after the first surgery, blood flow through the vascular loop was observed in all animals. Moreover, intimal proliferation tended to increase with the duration of the postoperative period. Two weeks after surgery, intimal proliferation increased slightly, whereas strong intimal proliferation was observed in all rats evaluated five weeks after surgery. CONCLUSION: Intimal proliferation was the most significant change noted in venous grafts as a function of the duration of the postoperative period and was directly correlated with graft occlusion. In cases in which vascular loops are required during free flap reconstruction, both procedures should preferably be performed during the same surgery.

A necktie fashion vascular loop seton tie may simplify the treatment of perianal fistula / O seton para alça vascular com laçada em forma de nó de gravata pode simplificar o tratamento da fístula perianal

ABSTRACT Seton for treatment of perianal fistula can be of the cutting or a loose type. We adopted a simple technique for tighten the seton by applying a necktie shape tie on the vascular loop, hence it can be used for drainage on the beginning, and for cutting purpose later on. In this retrospective study we report our experience on this seton tie method. Material and methods: Patients operated for perianal fistula between 2012 and 2014 were reviewed. Results: Of 63 patients operated, 23 (35%) had a necktie-tie seton. There were 15 (65%) men. Age 34.1 ± 10.6. Six (26%) had a recurrent fistula, 2 (9%) with loose seton in place. The external opening: anterior four (17%), lateral fifteen (65%), posterior three (13%), one patient (4%) had two opening. The internal opening was identified: posterior seventeen (74%), anterior four (17%) and right posterior two (8%). Nineteen (82%) had a trans-sphenteric tract, four (17%) females had an anterior location. Operative time was 32 min (range 22-55). The seton was tightened 4 times (range 2-5) with 2 weeks interval. Healing was achieved in 7 weeks (range 5-11). In 24 months (range 12-35) follow-up, no reported anal incontinence. Recurrence was observed in one patient (4%). Conclusion: The necktie tightening of the vascular loop seton is a simple, safe, easily performed and may simplify the seton management of perianal fistulae.

RESUMO Setons para o tratamento de fístula perianal podem ser do tipo de corte ou do tipo frouxo. Adotamos uma técnica simples para apertar o seton, pela aplicação, na alça vascular, de uma laçada em forma de nó de gravata. Desse modo, inicialmente a laçada pode ser utilizada para drenagem e, subsequentemente, para as finalidades de corte. Neste estudo retrospectivo, relatamos nossa experiência com este método de aplicação da laçada do Seton em nó de gravata. Material e métodos: Foram revisados pacientes operados para fístula perianal entre 2012-2014. Resultados: Dos 63 pacientes operados, 23 (35%) receberam um Seton em nó de gravata. Desse total, 15 (65%) eram homens, com média de idade de 34,1 ± 10,6 anos. Seis (26%) tiveram fístula recorrente, e dois (9%) tiveram afrouxamento do seton in loco. Foram identificadas aberturas externas: anteriores, quatro (17%); laterais, 15 (65%); posteriores, três (13%); e duas aberturas em um paciente (4%). Também foram identificadas aberturas internas: posteriores, 17 (74%); anteriores, quatro (17%); e posteriores direitas, duas (8%). Em 19 (82%) havia um trato trans-esfinctérico, e quatro pacientes mulheres (17%) tiveram localização anterior. O tempo de cirurgia foi de 32 minutos (variação, 22-55). O seton foi apertado 4 vezes (variação, 2-5) a intervalos de 2 semanas. A cicatrização ocorreu em sete semanas (variação, 5-11). Ao longo dos 24 meses (variação, 12-35) de seguimento dos pacientes, não houve relato de incontinência anal. Houve recorrência em um paciente (4%). Conclusão: O aperto do Seton em alça vascular pela técnica do nó de gravata é método simples, seguro, de fácil realização e que pode simplificar o tratamento de fístulas perianais com Seton.

Effects of intraoperative diltiazem infusion on flow changes in arterial and venous grafts in coronary artery bypass graft surgery / Efeitos da infusão intraoperatória de diltiazem sobre as mudanças do fluxo em enxertos arteriais e venosos em cirurgia de revascularização do miocárdio

AbstractObjective:This study aimed to show the effects of intra-operative diltiazem infusion on flow in arterial and venous grafts in coronary artery bypass graft surgery.Methods:Hundred fourty patients with a total of 361 grafts [205 (57%) arterial and 156 (43%) venous] underwent isolated coronary surgery. All the grafts were measured by intraoperative transit time flow meter intra-operatively. Group A (n=70) consisted of patients who received diltiazem infusion (dose of 2.5 microgram/kg/min), and Group B (n=70) didn't receive diltiazem infusion.Results:Mean graft flow values of left internal mammary artery were 53 ml/min in Group A and 40 ml/min in Group B (P<0.001). Pulsatility index (PI) values of left internal mammary artery for Group A and Group B were 2.6 and 3.0 respectively (P<0.001). No statistically significant difference was found between venous graft parameters.Conclusion:We recommend an effect of diltiazem infusion in increasing graft flows in coronary artery bypass graft operations.

ResumoObjetivo:Este estudo teve como objetivo mostrar os efeitos da infusão de diltiazem intraoperatória no fluxo arterial e enxertos venosos em cirurgia de revascularização do miocárdio.Métodos:Cento e quarenta pacientes com um total de 361 enxertos [205 (57%) arteriais e 156 (43%) venosos] passaram por uma cirurgia coronária isolada. Todos os enxertos foram medidos pelo medidor de fluxo de tempo de trânsito intraoperatório. Grupo A (n=70), formado por pacientes que receberam infusão de diltiazem (dose de 2,5 micrograma/kg/min), e Grupo B (n=70), por aqueles que não receberam infusão de diltiazem.Resultados:Os valores médios de fluxo de enxerto de artéria mamária interna esquerda foram 53 ml/min no grupo A e 40 ml/min no Grupo B (P<0,001). Valores do índice de pulsatilidade da artéria mamária interna esquerda para o Grupo A e do Grupo B foram de 2,6 e 3,0, respectivamente (P<0,001). Não houve diferença estatisticamente significativa entre os parâmetros do enxerto venoso.Conclusão:Sugerimos um efeito da infusão de diltiazem em aumentar os fluxos de enxerto em operações de bypass de artéria coronária.

Effects of intraoperative diltiazem infusion on flow changes in arterial and venous grafts in coronary artery bypass graft surgery.

OBJECTIVE: This study aimed to show the effects of intra-operative diltiazem infusion on flow in arterial and venous grafts in coronary artery bypass graft surgery. METHODS: Hundred fourty patients with a total of 361 grafts [205 (57%) arterial and 156 (43%) venous] underwent isolated coronary surgery. All the grafts were measured by intraoperative transit time flow meter intra-operatively. Group A (n=70) consisted of patients who received diltiazem infusion (dose of 2.5 microgram/kg/min), and Group B (n=70) didn't receive diltiazem infusion. RESULTS: Mean graft flow values of left internal mammary artery were 53 ml/min in Group A and 40 ml/min in Group B (P<0.001). Pulsatility index (PI) values of left internal mammary artery for Group A and Group B were 2.6 and 3.0 respectively (P<0.001). No statistically significant difference was found between venous graft parameters. CONCLUSION: We recommend an effect of diltiazem infusion in increasing graft flows in coronary artery bypass graft operations.

Early postoperative changes in hematological, erythrocyte aggregation and blood coagulation parameters after unilateral implantation of polytetrafluoroethylene vascular graft in the femoral artery of beagle dogs.

PURPOSE: The failure of small-caliber vascular grafts still means a serious problem. Concerning the early postoperative complications we aimed to investigate the hemostaseological and hemorheological aspects of this issue in a canine model. METHODS: In the Control group only anesthesia was induced. In the Grafted group under general anesthesia a 3.5-cm segment was resected unilaterally from the femoral artery and replaced with a PTFE graft (diameter: 3 mm). On the 1st-3rd-5th-7th and 14th postoperative days the skin temperature of both hind limbs was measured, and blood sampling occurred for hematological, hemostaseological and hemorheological tests. RESULTS: The skin temperature of the operated versus intact limbs did not differ. In the Grafted group leukocyte count was elevated by the 1st postoperative day, while platelet count increased over the entire follow-up period. Fibrinogen concentration rose on the 1st-5th days, activated partial thromboplastin time increased on the 3rd-7th days. Erythrocyte aggregation was enhanced significantly on the 1st-5th days. In specimens taken on the 14th day, histologically we found matured thrombus narrowing the graft lumen. CONCLUSIONS: Small-caliber PTFE graft implantation into the femoral artery caused significant changes in several hemostaseological and hemorheological parameters. However, better clarifying the factors leading to early thrombosis of these grafts needs further studies.

Early postoperative changes in hematological, erythrocyte aggregation and blood coagulation parameters after unilateral implantation of polytetrafluoroethylene vascular graft in the femoral artery of beagle dogs

PURPOSE: The failure of small-caliber vascular grafts still means a serious problem. Concerning the early postoperative complications we aimed to investigate the hemostaseological and hemorheological aspects of this issue in a canine model. METHODS: In the Control group only anesthesia was induced. In the Grafted group under general anesthesia a 3.5-cm segment was resected unilaterally from the femoral artery and replaced with a PTFE graft (diameter: 3 mm). On the 1st-3rd-5th-7th and 14th postoperative days the skin temperature of both hind limbs was measured, and blood sampling occurred for hematological, hemostaseological and hemorheological tests. RESULTS: The skin temperature of the operated versus intact limbs did not differ. In the Grafted group leukocyte count was elevated by the 1st postoperative day, while platelet count increased over the entire follow-up period. Fibrinogen concentration rose on the 1st-5th days, activated partial thromboplastin time increased on the 3rd-7th days. Erythrocyte aggregation was enhanced significantly on the 1st-5th days. In specimens taken on the 14th day, histologically we found matured thrombus narrowing the graft lumen. CONCLUSIONS: Small-caliber PTFE graft implantation into the femoral artery caused significant changes in several hemostaseological and hemorheological parameters. However, better clarifying the factors leading to early thrombosis of these grafts needs further studies. .

Arm vein as an alternative autogenous conduit for infragenicular bypass in the treatment of critical limb ischaemia: a 15 year experience.

OBJECTIVES: The value of alternative autogenous venous conduits for treating critical limb ischaemia (CLI) with infragenicular bypass surgery is well established. In this study, the results of using arm veins as alternative conduits for treating CLI over a 15-year period have been evaluated. METHODS: This was a retrospective study. Between 1991 and 2005. 120 infragenicular bypasses using arm vein conduits (AVCs) were performed in 120 patients. CLI was the main indication (87.5%) for the procedures. The indications for using arm veins were inadequacy or absence of the ipsilateral greater saphenous vein (GSV). Survival, limb salvage, and patency rates were calculated using the Kaplan-Meier method. RESULTS: There was a predominance of male gender (65%), and the group mean age was 68.1 ± 8.3 years. The mean follow-up period was 29.6 ± 26.3 months. The operative mortality (30 days) rate was 7.5%. The main alternative conduit was non-spliced cephalic vein (37.5%). Composite grafts included GSV + AVC (45.2%), AVC + AVC (43.3%) and small saphenous vein + AVC (11.5%). The 5-year primary and secondary patency (SP) rates were 45.2 ± 5.6% and 56.5 ± 5.0%, respectively. The 5-year SP rate was greatest when using non-spliced cephalic vein (65.8 ± 7.6%), but there was no difference in cumulative patency between spliced and non-spliced veins (49.5 ± 8.0% vs. 61.2 ± 6.4%; p = 0.501). The 5-year limb salvage and survival rates were 70.6 ± 5.9% and 59.6 ± 5.8%, respectively. CONCLUSIONS: The favourable long term results of secondary patency and limb salvage rates encourage the use of arm veins as alternative conduits for infragenicular bypass surgery.

Lateral approach to the peroneal artery without resection of the fibula for lower limb revascularization.

The peroneal artery is an important outflow vessel for lower limb revascularization and limb salvage. This vessel is commonly reached using a medial, posterior, or lateral approach with resection of the fibula. We present a technique of lateral approach to the peroneal artery without fibular resection.

Vascular access in haemodialysis: strengthening the Achilles' heel.

Despite all the progress achieved since Scribner first introduced the arteriovenous (AV) shunt in 1960 and Cimino and Brescia introduced the native AV fistula in 1962, we have continued to face a conundrum in vascular access for dialysis, in that dialysis vascular access is at the same time both the 'lifeline' and the 'Achilles' heel' of haemodialysis. Indeed, findings from a multitude of published articles in this area, unfortunately mainly observational studies, reflect both our frustration and our limited knowledge in this area. Despite improved understanding of the pathophysiology of stenosis and thrombosis of the vascular access, we have unfortunately not been very successful in translating these advances into either improved therapies or a superior process of care. As a result, we continue to face an epidemic of arteriovenous fistula (AVF) maturation failure, a proliferation of relatively ineffective interventions such as angioplasty and stent placement, an extremely high incidence of catheter use, and more doubts rather than guidance with regard to the role (or lack thereof) of surveillance. An important reason for these problems is the lack of focused translational research and robust randomized prospective studies in this area. In this Review, we will address some of these critical issues, with a special emphasis on identifying the best process of care pathways that could reduce morbidity and mortality. We also discuss the potential use of novel therapies to reduce dialysis vascular access dysfunction.

Post-implant evaluation of the anastomotic biomechanical coupling between human native arteries and arterial cryografts implanted in lower-limb revascularization procedures.

In the past, the reduced availability and problems with the preservation/storage limited the use of cryopreserved /defrosted arteries (cryografts) in lower limb revascularization procedures. However, the recent development of cryopreservation techniques enhanced cryografts availability and value, and renewed the interest in their use as vascular substitutes. Anyway, some issues related with the cryografts properties and with their usefulness remain to be clarified.

Achados de imagem da revascularização do miocárdio pela tomografia computadorizada por múltiplos detectores: onde estão os enxertos? Ensaio iconográfico / Imaging findings of myocardial revascularization at multidetector computed tomography: where are the bypass grafts? An iconographic essay

A angiotomografia por multidetectores de coronárias constitui um método preciso para avaliação dos enxertos venosos e arteriais pós-revascularização coronariana e vem substituindo em parte o cateterismo, o qual é um método invasivo e de maior custo. Este ensaio iconográfico tem como objetivo a demonstração anatômica dos enxertos mais comumente utilizados, como diferenciar enxertos venosos e arteriais e como localizá-los. Os exames foram realizados em aparelhos de tomografia computadorizada multislice de 64 fileiras de detectores, com apneia, frequência cardíaca controlada e protocolos adequados com posterior reconstruções MPR, MIP e 3D, de acordo com o eletrocardiograma. A localização dos enxertos e anastomoses em tomografias computadorizadas direcionadas para as artérias coronárias e para o tórax pode dificultar a análise do exame pelo radiologista não familiarizado, sendo que o conhecimento das técnicas cirúrgicas utilizadas e dos possíveis trajetos das pontes de safena e enxertos arteriais ajuda na análise de ambos os exames, evitando também erros diagnósticos.

Multidetector coronary computed tomography angiography is a precise method for evaluating post-coronary revascularization arterial and venous bypass grafts, and is somehow superseding coronary catheterization that is an invasive and more expensive technique. The present iconographic essay is aimed at anatomically demonstrating the bypass grafts most frequently utilized, how to differentiate between arterial and venous grafts and how to find them. The studies were performed in 64-row multidetector computed tomography equipment, with breath hold, controlled heart rate and appropriate protocols with later MPR, MIP and 3D reconstructions according to electrocardiogram. The localization of the bypass grafts and anastomoses at computed tomography studies focused on chest and coronary arteries may represent a difficulty in the images analysis by the radiologist who is not familiar with the matter, so the knowledge of the surgical techniques adopted and possible courses of the saphenous bypass grafts and arterial grafts can aid in the analysis of both studies, avoiding diagnostic errors.