Effect of local papaverine on arteriovenous fistula maturation in patients with end-stage renal disease / Efeito da papaverina local na maturação de fístulas arteriovenosas em pacientes com doença renal terminal

Abstract Background: Arteriovenous fistula (AVF) maturation is one of the main concerns in patients with end-stage renal disease (ESRD) and finding a strategy for increasing success rate and accelerating fistula maturation is valuable. The aim of this study was to evaluate the effects of papaverine injection on AVF maturation and success rate. Method: This study was a randomized clinical trial that involved 110 patients with ESRD that were referred for AVF construction. Patients were allocated in papaverine group and control group with block randomization according to age and sex. In the case group, papaverine (0.1 or 0.2 cc) was injected locally within the subadventitia of artery and vein after proximal and distal control during AVF construction and in the control group, AVF construction was done routinely without papaverine injection. Results: Maturation time in case and control groups was 37.94 ± 11.49 and 44.23 ± 9.57 days, respectively (p=0.004). Hematoma was not seen in the case group but occurred in one patient in the control group. One patient of the case group developed venous hypertension. Four functional fistulas, 1 (1.8%) in the case group and 3 (5.5%) in the control group, failed to mature (p=0.618). Maturation rate did not differ between the two groups statistically (p=0.101). Conclusion: Local papaverine injection increased vessel diameter and blood flow, increasing shearing stress in both arterial and venous segment of recently created AVF. In this way, papaverine probably can decrease AVF maturation time without an increase in complications.

Resumo Introdução: A maturação da fístula arteriovenosa (FAV) é uma das principais preocupações em pacientes com doença renal terminal (DRT). Assim, é importante identificar estratégias para aumentar as taxas de sucesso e acelerar a maturação da fístula. O objetivo do presente estudo foi avaliar os efeitos da infiltração de papaverina sobre a maturação da FAV e suas taxas de sucesso. Método: O presente ensaio clínico randomizado incluiu 110 pacientes com DRT encaminhados para colocação de FAV. Os pacientes foram randomizados em bloco em função de idade e sexo e alocados nos grupos caso ou controle. Os indivíduos no grupo caso receberam infiltração local de papaverina (0,1 ou 0,2 ml) no plano da sub-adventícia da artéria e veia após o controle proximal e distal durante a construção da FAV. No grupo controle, a construção da FAV foi realizada rotineiramente sem infiltração de papaverina. Resultados: Os tempos de maturação dos grupos caso e controle foram 37,94 ± 11,49 e 44,23 ± 9,57 dias, respectivamente (p = 0,004). Foi observado hematoma em apenas um paciente do grupo controle. Um paciente do grupo caso desenvolveu hipertensão venosa. Quatro fístulas funcionais, uma (1,8%) no grupo caso e três (5,5%) no grupo controle, não amadureceram (p = 0,618). A taxa de maturação não diferiu estatisticamente entre os dois grupos (p = 0,101). Conclusão: A infiltração local de papaverina aumentou o diâmetro do vaso e o fluxo sanguíneo, elevando a tensão de cisalhamento nos segmentos arterial e venoso da FAV recentemente criada. Desta forma, a papaverina provavelmente consegue reduzir o tempo de maturação da FAV sem aumentar as complicações.

Are high flow arteriovenous accesses associated with worse haemodialysis? / Acessos arteriovenosos de alto débito estão associados a pior hemodiálise?

ABSTRACT Introduction: An arteriovenous (AV) access flow (Qa) of 400 mL/min is usually sufficient for an effective hemodialysis (HD), but some accesses continue developing and become high flow accesses (HFA). Some authors postulated that an HFA might shift a significant portion of dialyzed blood from the cardiac output, which could decrease HD efficiency and lead to volume overload. Objective: The aim of our study was to evaluate if HFA is associated with reduced HD efficiency and/or volume overload in prevalent HD patients. Methods: We performed a 1-year retrospective study and assessed HD efficiency by the percentage of sessions in which the Kt/V > 1.4 and volume overload by bioimpedance spectroscopy. Results: The study included 304 prevalent HD patients with a mean age of 67.5 years; 62.5% were males, 36.2% were diabetics, with a median HD vintage of 48 months. Sixteen percent of the patients had a HFA (defined as Qa > 2 L/min). In multivariate analysis, patients with HFA presented higher risk of volume overload (OR = 2.67, 95%CI = 1.06-6.71) and severe volume overload (OR = 4.06, 95%CI = 1.01-16.39) and attained dry weight less frequently (OR = 0.37, 95%CI = 0.14-0.94). However, HFA was not associated with lower Kt/V. Conclusion: Our results suggest that patients with HFA have higher risk of volume overload. However, contrarily to what has been postulated, HFA was not associated with less efficient dialysis, measured by Kt/V. Randomized controlled trials are needed to clarify these questions.

RESUMO Introdução: Um débito de sangue de acesso arteriovenoso (AV) (Qa) de 400 mL/min é geralmente suficiente para uma hemodiálise (HD) eficaz, mas alguns acessos continuam se desenvolvendo e se tornam acessos de alto débito (AAD). Alguns autores postularam que um AAD poderia desviar uma porção significativa do sangue dialisado do débito cardíaco, o que poderia diminuir a eficiência da HD e levar à sobrecarga de volume. Objetivo: O objetivo do nosso estudo foi avaliar se o AAD está associado à redução da eficiência da HD e/ou à sobrecarga de volume em pacientes prevalentes em HD. Métodos: Foi realizado um estudo retrospectivo de 1 ano, e avaliada a eficiência da HD pela porcentagem de sessões em que o Kt/V > 1,4 e a sobrecarga de volume avaliada pela bioimpedância. Resultados: O estudo incluiu 304 pacientes prevalentes em HD, com média de idade de 67,5 anos; 62,5% eram do sexo masculino; 36,2% eram diabéticos, com uma mediana de tempo em HD de 48 meses. Dezesseis por cento dos pacientes apresentavam AAD (definida como Qa > 2 L/min). Na análise multivariada, os pacientes com AAD apresentaram maior risco de sobrecarga de volume (OR = 2,67; IC95% = 1,06-6,71) e sobrecarga severa de volume (OR = 4,06; IC95% = 1,01-16,39) e atingiram o peso seco com menor frequência (OR = 0,37, IC 95% = 0,14-0,94). No entanto, o AAD não foi associado uma menor razão Kt/V. Conclusão: Nossos resultados sugerem que pacientes com AAD apresentam maior risco de sobrecarga de volume. No entanto, ao contrário do que foi postulado, o AAD não foi associado à diálise menos eficiente, medida pelo Kt/V. Ensaios clínicos randomizados são necessários para esclarecer essas questões.

Transposition of Great Arteries with Intramural Coronary Artery: Experience with a Modified Surgical Technique

Abstract Objective: Transposition of the great arteries is a common congenital heart disease. Arterial switch is the gold standard operation for this complex heart disease. Arterial switch operation in the presence of intramural coronary artery is surgically the most demanding even for the most experienced hands. We are presenting our experience with a modified technique for intramural coronary arteries in arterial switch operation. Methods: This prospective study involves 450 patients undergoing arterial switch operation at our institute from April 2006 to December 2013 (7.6 years). Eighteen patients underwent arterial switch operation with intramural coronary artery. The coronary patterns and technique used are detailed in the text. Results: The overall mortality found in the subgroup of 18 patients having intramural coronary artery was 16% (n=3). Our first patient had an accidental injury to the left coronary artery and died in the operating room. A seven-day old newborn died from intractable ventricular arrhythmia fifteen hours after surgery. Another patient who had multiple ventricular septal defects with type B arch interruption died from residual apical ventricular septal defect and sepsis on the eleventh postoperative day. The remainder of the patients are doing well, showing a median follow-up duration of 1235.34±815.26 days (range 369 - 2730). Conclusion: Transposition of the great arteries with intramural coronary artery is demanding in a subset of patients undergoing arterial switch operation. We believe our technique of coronary button dissection in the presence of intramural coronary arteries using coronary shunt is simple and can be a good addition to the surgeons' armamentarium.

Fístula arterio-venosa como tratamiento de EPOC grave / Arteriovenous fistula in the treatment of severe COPD

COPD patients have dyspnea limiting their exercise capacity due to different mechanisms. The origin of the arterial blood gases anomaly is an alteration of the ventilation/perfusion (V'/Q') ratio causing venous admixture which has not been addressed therapeutically so far. Theoretically an arteriovenous fistula (AVF) could increase venous content of O2 so that blood leaving the left ventricle has a higher than expected PaO2 .This, along with the associated increase in cardiac output leads to an increased delivery of O2 to tissues particularly skeletal muscle thus improving its performance. We present a patient with advanced COPD. Full conventional therapy failed to improve his dyspnea and hypoxemia which limits his exercise capacity. We made a peripheral arteriovenous fistula on him as a therapeutic intent. Spirometry showed an initial FEV1 of 0.74 L, a FVC of 1.97 L, he had hypoxemia (PaO2 :56.8 mmHg, oxyhemoglobin saturation (SaO2 ): 82.9 percent). A 6 min walking test with a distance of300 m corresponding to 61 percent of predetermined value that improved by 108 m providing O2 2 L/min. Echocardiography showed a pulmonary artery systolic pressure of 26 mm Hg and a 60 percent of left ventricle ejection fraction. The patient obtained 73.8 percent in Saint George's Respiratory Questionnaire (SGRQ), 38 points in COPD Assesment Test (CAT) and 6 points in BODE Index. After 4 weeks of AVF neither spirometric nor echocardiographic changes were observed, but there was an improvement in PaO2 to 68 mmHg and in SaO2 to 93 percent. The 6 min walking test showed an increase to 425 m. SGRQ improved to 3.88 points, BODE index improved to 3 points and CAT to 21 points. We conclude that in this patient an AVF determined an improvement in exercise capacity with a better control of disease that resulted in a better quality of life constituting an important non pharmacological aid in an advanced COPD patient who failed to improve with full medical therapy. In patients selection...

El paciente portador de EPOC tiene disnea que limita su capacidad de ejercicio por diferentes mecanismos entre los cuales está la incapacidad de la musculatura respiratoria para responder al aumento de las demandas, que puede ser secundaria a la disminución de la entrega de O2. La anomalía gasométrica propia de la enfermedad tiene como origen una alteración de la relación ventilación/ perfusión (V'/Q') que causa un aumento de la admisión venosa el cual no ha sido enfrentado terapéuticamente hasta el momento. Teóricamente una fístula arteriovenosa (FAV) podría aumentar el contenido venoso de O2 ,de modo que la sangre que sale del ventrículo izquierdo lo haga con una PaO2 mayor que la esperada. Esto, junto con el aumento del gasto cardíaco asociado llevaría a una mayor entrega de O2 a los tejidos mejorando de esa forma el desempeño de la musculatura esquelética. En un paciente con EPOC avanzada que con terapia máxima no logra mejorar la disnea ni la hipoxemia que limitan seriamente su capacidad de ejercicio, confeccionamos una fistula entre la vena safena interna y la arteria femoral superficial con intención terapéutica. La espirometría inicial mostró un VEF1de 0,74 L (26 por ciento del valor predeterminado) con CVF de 1,97 L (57 por ciento). Presentaba hipoxemia (PaO2 :56,8 mmHg y SaO2 :82,9 por ciento), un test de caminata de 6 min (TC6M) con un recorrido de 300 m que corresponde a un 61 por ciento del teórico que mejoraba al aportar O2 2 L/min a 408 m correspondiente a un 80 por ciento del teórico. El ecocardiograma detectó una presión sistólica de arteria pulmonar de 26 mmHg y una fracción de eyección del ventrículo izquierdo de 60 por ciento. En el cuestionario respiratorio de Saint George el paciente obtuvo 73,8 por ciento su CAT (COPD Assessment Test) fue de 38 puntos y su índice BODE (Body mass, Obstruction, Dyspnea, Exercise capacity) de 6 puntos. Al mes de realizada la FAVno hubo cambios espirométricos ni ecocardiográficos, pero la PaO2 mejoró a...

Latero-lateral femoro-femoral arteriovenous fistula: a new surgical approach for hemodialysis patients with no vascular access / Fístula artériovenosa fêmoro-femoral látero-lateral: uma nova abordagem para hemodiálise de pacientes sem opção de acesso vascular

Purpose: A new surgical approach for vascular access for hemodialysis using a latero-lateral arteriovenous fistula (AVF) in the thigh between the femoral artery (FA) and superficial femoral vein (SFV) transposed to the subcutaneous layer in patients with no other access options is described. Methods: Ten patients (mean age: 37,9 years) for whom all possible sites for execution of any other procedure had been exhausted, underwent latero-lateral AVF close to the adductor channel between the FA and the SFV. The FSV was released and sectioned 2 cm from its confluence with the deep femoral vein and transposed in the subcutaneous tissue with extensions using saphenous vein or prosthetic material (PTFE) when needed. Follow -up included patency, flow evaluation and complications. Results: Postoperative follow-up ranged from 3 to 96 months, with a mean of 38 months. The AVFs presented a flow of more than 350 ml/min and the AVFs remained patent for a mean period of 38 months. There were three failures of the procedures at 3, 5 and 7 months during postoperative follow-up due to graft infection and thrombosis (a case), anaphylactic shock and thrombosis (a case) and calf pain during dialysis (a case). Two patients developed slight inferior limb edema. Conclusion: The new surgical approach for access for hemodialysis represents a feasible procedure, with acceptable patency rates in exceptional cases where no other access option is available.

Objetivo: Nova abordagem para acesso vascular para hemodiálise usando fistula artério-venosa (FAV) látero-lateral na coxa entre a artéria femoral (AF) e a veia femoral superficial (VFS) transposta no subcutâneo em pacientes sem opção de acesso. Métodos: Dez pacientes (idade média 37,9 anos), cuja possibilidade de acesso havia sido exaurido, foram submetidos a FAV látero-lateral na coxa entre a AF e a VFS.Esta veia foi liberada e seccionada 2 cm de sua confluência com a veia femoral profunda e transposta no plano superficial com extensão usando a veia safena ou material protético (PTFE) quando necessário.O seguimento incluíu a perviedade , fluxo e complicações. Resultados: O seguimento pós-operatório foi de 3 a 96 meses (média 38). A FAV apresentou fluxo mínimo de 350 ml/min e permaneceu pérvia no período médio de 38 meses. Houve 3 falências aos 3, 5, e 7 meses pós-operatórios por infecção de prótese e trombose da FAV (um caso), choque anafilático e trombose (um caso) e dor na panturrilha na hemodiálise (um caso). Dois pacientes desenvolveram discreto edema de membro inferior. Conclusão: A nova abordagem para acesso vascular para hemodiálise representa um procedimento factível, com aceitável perviedade em casos excepcionais onde nenhum outro acesso é disponível.

Experience with arteriovenous fistulas for chronic hemodialysis in children: technical details and refinements

OBJETIVO: Relatar a experiência dos autores na execução de fístulas artério-venosas em crianças, com a utilização dos recursos da microcirurgia vascular, com especial ênfase aos detalhes de técnica cirúrgica. MÉTODOS: Os pacientes foram operados entre julho de 1997 e março de 2004. Foram utilizadas lupas cirúrgicas (aumento de 3,5 vezes). Após a dissecção da veia e da artéria, a anastomose veno-arterial foi realizada de forma término-lateral, com quatro suturas contínuas de fio 7/0 ou 8/0. RESULTADOS: Vinte e nove crianças foram operadas para a realização de 33 fístulas - 21 rádio-cefálicas, 6 bráquio-cefálicas, 4 bráquio-basílicas e 2 safeno-femorais. Obteve-se permeabilidade em 17/21 (80,9%) fístulas rádio-cefálicas, 5/6 (83,3%) bráquio-cefálicas, 3/4 (75,0%) bráquio-basílicas e 2/2 (100%) safeno-femorais. 2 pacientes apresentaram obstrução da fístula e da artéria radial e 2 outras fístulas rádio-cefálicas obstruíram-se entre a primeira e segunda semana de pós-operatório. Tardiamente, verificou-se que as fístulas safeno-femorais causaram edema do membro inferior correspondente e houve formação de aneurisma em uma fístula bráquio-cefálica. Quanto à permeabilidade, verificou-se que as fístulas bráquio-cefálicas e bráquio-basílicas apresentaram a mesma incidência de permeabilidade em comparação com as fístulas rádio-cefálicas (p>0,05). CONCLUSÃO: A presente casuística demonstra que as fístulas artério-venosas persistem como um bom acesso vascular para hemodiálise em crianças. A utilização de microcirurgia e alguns detalhes técnicos aqui descritos permitem a obtenção de bons índices de permeabilidade das fístulas.

The mid-forearm arteriovenous fistula as vascular access for haemodialysis

Successful chronic haemodialysis requires permanent vascular access. The Scribner procedure which utilizes an external arteriovenous shunt, the internal synthetic arteriovenous shunt and the direct arteriovenous fistula as described by Cimino and Brescia have all been used for haemodialysis. Of the three methods, the arteriovenous fistula is the most trouble-free and durable. However, as originally described and constructed in the distal forearm, the morbidity associated with this method is significant. The cubital fossa fistula has even more problems. The mid-forearm fistula was designed by the authors and has been used for chronic haemodialysis over the past eighteen years. This article compares the various methods of access used in the haemodialysis units of the University Hospital of the West Indies and the Kingston Regional Hospital. The mid-forearm fistula was found to have the lowest initial failure rate and was associated with fewer complications than any of the other methods used for access.

Accesos vasculares para hemodiálisis crónica en niños / Vascular accesses for hemodialysis in children

Background: The success of a chronic hemodialysis program depends on a good vascular access. Aim: To evaluate the experience with vascular accesses for chronic hemodialysis in pediatric patients. Patients and methods: One hundred fifty one vascular accesses used in 60 pediatric patients (33 female) coming from 2 hemodialysis (HD) centers were analyzed. Results: The average age of admission to the hemodialysis program was 10 years old (range 1.8-15). Forty percent of accesses were internal arterio-venous fistulae (AVF), 58 percent were central venous catheters and 2 percent were grafts. Twenty four patients required a central venous catheter from the beginning since they required immediate dialysis. Twenty patients began dialysis with a permeable AVF and never required another vascular access. Eight small children used a central catheter as the only vascular access and 32 patients required both types of vascular accesses. Eighty seven catheters were used in 34 patients, of which 77 were temporary and 10 permanent. Seventeen patients needed only one catheter and one girl required 15 catheters. The average life span for AVF was 524 days (20-1277), for temporary catheters 34 days (1-76) and for permanent catheters 73 days (9-147). Two years survival of AVF was 95 percent. One month survival for subclavian and jugular catheters was 50 percent. Fifty six percent of AVF had no complications, 12 failed due to insufficient flow and 24 percent had a complication. Of the 87 catheters placed, 75 percent had complications and 22 were electively removed. Conclusions: Arteriovenous fistula is the vascular access of choice for hemodialysis in pediatric patients. Central venous catheters can become an essential access, specially in small children

Fístula humero-basílico-mediana-cefálica: una alternativa en la hemodiálisis crónica / Thumeral basilic-medium-cephalic fistula: an alternative in chronic hemodialysis

El éxito del tratamiento de los pacientes en hemodiálisis crónica dependerá del mantenimiento de un acceso vascular adecuado. Se presenta una vía de acceso utilizando el eje venoso basílico-mediano-cefálico y la arteria humeral como alternativa cuando los vasos del antebrazo han sido empleados previamente. Brinda un amplio trayecto de punción, con nula participación del sistema venoso profundo y es de suma utilidad en niños ya que la mayor acumulación de tejido adiposo en la zona del antebrazo y muñeca, asociados al pequeño calibre de los vasos superficiales dificultan el acceso clásico