[Analysis of the survival of permanent vascular access ports]. / Análisis de supervivencia del acceso vascular permanente.

Complications arising from vascular access are major causes of morbidity in patients on renal replacement therapy. They contribute to frustration of health care providers and to high medical cost. To prevent failures in the future it will be helpful to identify the factors that are related to vascular access, malfunction. In a retrospective analysis we analysed the types, duration and primary patency rate of 1,033 permanent vascular access in 544 consecutive patients established during a 13-year period in a tertiary care hospital. Patient characteristics, incidence and risk factors related to vascular access failure were registered. In addition vascular access outcomes in patients who started haemodialysis with a catheter and in whom initial vascular access failure occurred were analysed separately. Forty-five per cent of patients required a central catheter at the start of HD, but 92% of them were being dialysed with an a-v fistula at the last observation. The total number of complications was 0.24 episodes per patient per year at risk, and the rate of thrombosis 0.1. A total of 52% of patients were dialysed throughout the observation period with their initial a-v fistula; 9.3% had more than three episodes of vascular access failure. The radiocephalic a-v fistula was the access with the best median duration, exceeding 7 years, but also the type that had the highest initial failure rate, i.e. 25% of patients and 13% of events. The brachiocephalic a-v fistula was the second most frequent type of vascular access, with a median duration of function of 3.6 years, in contrast the humerobasilar a-v fistula, lasted on average over 5 years. Average patency of the different types of grafts did not exceed 1 year, with the exception of the autologous saphenous graft with a median duration of function of 1.4 years. Patients with glomerulonephritis had the best function rates for their access, the median duration exceeding the duration of the study, whereas in half of diabetic patients it was less than 1 year. The duration of patency of the vascular access was twice as long in patients below age 65 years and in elderly males compared to elderly females. Patients who start HD with a catheter, as well as those with initial vascular access failure, have a higher rate of access failure in the subsequent course on renal replacement therapy. In conclusion, the radiocephalic and the brachiocephalic a-v fistula are the two types of vascular access with the longest duration of function, although a high rate of initial failure is seen with the radiocephalic a-v fistula. Age, female gender, presence of diabetic nephropathy, start of dialysis with a catheter, and failure to wait for initial maturation of vascular access are risk factors, and account for the majority of vascular access failure during renal replacement therapy.

Análisis de supervivencia del acceso vascular permanente / Survival analysis of permanent vascular access

Las complicaciones originadas por los accesos vasculares (AV) constituyen una de las principales causas de morbilidad en los pacientes en tratamiento sustitutivo renal (TSR), producen fuerte componente de frustración entre los profesionales implicados en su cuidado y contribuyen al alto coste sanitario. El conocimiento de los factores relacionados con su disfunción puede ayudar a prevenir futuros fracasos. Se analiza la distribución, duración y tasas de permeabilidad primaria de 1.033 AV permanentes diferentes implantados a 544 pacientes consecutivos durante un período de 13 años en un hospital terciario. Se estudia la tipología de los pacientes, las incidencias registradas y los factores de riesgo relacionados con el fracaso del AV. Asimismo, se analizan los resultados del AV en el grupo de pacientes que tuvieron que iniciar la HD mediante un catéter y en los que el desarrollo del AV fracasó inicialmente.Si bien el 45 por ciento de los pacientes precisan iniciar la HD a través de un catéter central, el 92 por ciento de los enfermos se dializan mediante una fístula arteriovenosa (FAV) en el momento de finalizar el estudio. La tasa de complicaciones totales fue de 0,24 episodios por paciente/año de riesgo y la de trombosis de 0,1. El 52,5 por ciento de los pacientes se dializaron durante todo el tiempo del estudio con su AV inicial, mientras que el 9,3 por ciento presentaron más de 3 fracasos de AV. La FAV radiocefálica es el AV autólogo que obtiene mayores medianas de duración (más de 7 años), pero también el que presenta mayor índice de fracasos iniciales (25 por ciento de los pacientes, 13 por ciento de los episodios). La FAV braquicefálica es el segundo AV implantado en orden de frecuencia y obtiene una duración de 3,6 años, mientras que la FAV humerobasílica supera los 5 años. La permeabilidad de las diferentes modalidades de injertos no sobrepasa el primer año, salvo el autólogo de safena que alcanza una mediana de 1,4. Los pacientes con nefropatía glo erular son los que obtienen mayores tasas de supervivencia de su AV ya que la mediana sobrepasa la duración del estudio, por el contrario la mitad de los diabéticos no alcanzan el primer año. El tiempo de permeabilidad del AV es doble en los menores de 65 años y en los varones en relación a los pacientes de mayor edad y a las mujeres. Tanto los pacientes que inician HD con catéter, como los que no logran el desarrollo inicial de su AV presentan mayor número de fracasos de su AV durante el tiempo de TSR. La FAV radiocefálica y la humerobasílica son los AV que alcanzan mayor duración, si bien la primera presenta alto índice de fracasos iniciales. La edad, el sexo femenino, la presencia de nefropatía diabética, el iniciar la HD mediante un catéter y la incapacidad para alcanzar la maduración inicial del AV constituyen factores de riesgo para presentar mayor número de fracasos de AV durante el TSR. (AU)

The function of permanent vascular access.

BACKGROUND: Complications arising from vascular access (VA) are major causes of morbidity in patients on renal replacement therapy (RRT). They contribute to frustration of health care providers and to high medical cost. To prevent failures in the future it will be helpful to identify the factors that are related to VA malfunction. METHODS: In a retrospective analysis we analysed the types, duration and primary rate of patency of 1033 permanent vascular accesses in 544 consecutive patients established during a 13-year period in a tertiary care hospital. Patient characteristics, incidence, and risk factors related to VA failure were registered. In addition, VA outcomes in patients who started haemodialysis with a catheter and in whom initial VA failure occurred were analysed separately. RESULTS: Forty-five per cent of patients required a central catheter at the start of HD, but 92% of them were being dialysed with an a-v fistula at the last observation. The total number of complications was 0.24 episodes per patient per year at risk and the rate of thrombosis 0.1. A total of 52% of patients were dialysed throughout the observation period with their initial a-v fistula; 9.3% had more than three episodes of VA failure. The radiocephalic a-v fistula was the VA with the best median duration, exceeding 7 years, but also the type that had the highest initial failure rate, i.e. 25% of patients and 13% of the events. The brachiocephalic a-v fistula was the second most frequent type of VA, with a median duration of function of 3.6 years, in contrast to the humerobasilic a-v fistula, which exceeded 5 years. Average patency of the different types of grafts did not exceed 1 year, with the exception of the autologous saphenous graft with a median duration of function of 1.4 years. Patients with glomerulonephritis had the best function rates for their VA, the median exceeding the duration of the study, whereas in half of the diabetic patients it was less than 1 year. The duration of patency of the VA was twice in patients below age 65 years and in elderly males compared to elderly females. Patients who started HD with a catheter, as well as those with initial VA failure, had a higher rate of VA failure in the subsequent course on RRT. CONCLUSION: The radiocephalic and the humerobasilic a-v fistulae are the two types of VA with the longest duration of function, although a high rate of initial failure is seen with the radiocephalic a-v fistula. Age, female gender, presence of diabetic nephropathy, start of dialysis with a catheter, and failure to wait for initial maturation of the VA are risk factors, and account for the majority of VA failures during RRT.