RESUMEN
Several organ allocation protocols give priority to wait-listed simultaneous kidney-pancreas (SPK) transplant recipients to mitigate the higher cardiovascular risk of patients with diabetes mellitus on dialysis. The available information regarding the impact of preemptive simultaneous kidney-pancreas transplantation on recipient and graft outcomes is nonetheless controversial. To help resolve this, we explored the influence of preemptive simultaneous kidney-pancreas transplants on patient and graft survival through a retrospective analysis of the OPTN/UNOS database, encompassing 9690 simultaneous transplant recipients between 2000 and 2017. Statistical analysis was performed applying a propensity score analysis to minimize bias. Of these patients, 1796 (19%) were transplanted preemptively. At ten years, recipient survival was significantly superior in the preemptive group when compared to the non-preemptive group (78.9% vs 71.8%). Dialysis at simultaneous kidney-pancreas transplantation was an independent significant risk for patient survival (hazard ratio 1.66 [95% confidence interval 1.32-2.09]), especially if the dialysis duration was 12 months or longer. Preemptive transplantation was also associated with significant superior kidney graft survival compared to those on dialysis (death-censored: 84.3% vs 75.4%, respectively; estimated half-life of 38.57 [38.33 -38.81] vs 22.35 [22.17 - 22.53] years, respectively). No differences were observed between both groups neither for pancreas graft survival nor for post-transplant surgical complications. Thus, our results sustain the relevance of early referral for pancreas transplantation and the importance of pancreas allocation priority in reducing patient mortality after simultaneous kidney-pancreas transplantation.
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Diabetes Mellitus Tipo 1 , Trasplante de Riñón , Trasplante de Páncreas , Diabetes Mellitus Tipo 1/cirugía , Supervivencia de Injerto , Humanos , Trasplante de Riñón/métodos , Páncreas , Trasplante de Páncreas/efectos adversos , Estudios RetrospectivosRESUMEN
Primary membranous nephropathy (PMN) is an autoimmune disease limited to the kidney that is characterized by the presence of circulating PLAR2 antibodies in 70% of the cases and usually positivity for PLA2R and IgG4 by immunohistochemistry (IHC) staining. We report the first documented case of PMN (PLA2R positive) in a deceased kidney donor, transplanted to two different recipients and their clinical and immunological evolution through serial biopsies. Recipient A's first allograft biopsy (Day 26) was compatible with a MN with both positive PLA2R and IgG4 subepithelial deposits in IHC. The donor's preimplantation kidney biopsies were retrieved and reexamined, revealing MN, with high intensity for PLA2R and IgG4 in IHC. Recipient B's protocol allograft biopsy, performed later at 3 months, also revealed histology compatible with MN but without the presence of PLA2R nor IgG4 in IHC. At 1-year follow-up, both recipients maintain graft function. Serial protocol biopsies were performed in both patients showing disappearance of IgG4 in recipient A but the persistence of PLA2R in IHC. We can conclude that, given the reversal of PMN changes in the grafts, it could be considered to transplant a patient from an asymptomatic deceased donor with PMN as long as he maintains unaltered renal function.
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Glomerulonefritis Membranosa , Trasplante de Riñón , Autoanticuerpos , Biopsia , Humanos , Inmunoglobulina G , Riñón , Trasplante de Riñón/efectos adversos , Masculino , Receptores de Fosfolipasa A2 , Donantes de TejidosRESUMEN
INTRODUCTION: COVID-19 is a highly contagious disease that has easily spread worldwide. Outpatient maintenance hemodialysis seems to entail an increased risk of contagion, and previous reports inform of increased mortality among this population. METHODS: We retrospectively analyzed clinical and laboratory parameters, outcomes, and management once discharged of CKD-5D patients infected with SARS-CoV-2 from our health area. RESULTS: Out of the 429 CKD-5D population, 36 were diagnosed with SARS-CoV-2 infection (8%): 34 on in-center hemodialysis and 2 on peritoneal dialysis. Five were asymptomatic. The most common symptom was fever (70%), followed by dyspnea and cough. History of cardiovascular disease and elevation of LDH and C-reactive protein during admission were associated with higher mortality. Thirteen patients died (36%), 8 patients were admitted to an ICU, and survival was low (38%) among the latter. The mean time to death was 12 days. Most discharged patients got negative rRT-PCR in nasopharyngeal swabs within 26 days of diagnosis. However, there is a portion of cured patients that continue to have positive results even more than 2 months after the initial presentation. CONCLUSIONS: Patients on dialysis have an increased mortality risk if infected with SARS-CoV-2. Preventive measures have proven useful. Thus, proper ones, such as universal screening of the population and isolation when required, need to be generalized. Better de-isolation criteria are necessary to ensure an appropriate use of public health resources.
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COVID-19/epidemiología , Aislamiento de Pacientes , Insuficiencia Renal Crónica/epidemiología , SARS-CoV-2 , Cuidados Posteriores , Anciano , Anciano de 80 o más Años , Infecciones Asintomáticas/epidemiología , COVID-19/diagnóstico , COVID-19/prevención & control , COVID-19/transmisión , Prueba de COVID-19 , Enfermedades Cardiovasculares/epidemiología , Comorbilidad , Diabetes Mellitus/epidemiología , Dislipidemias/epidemiología , Femenino , Fiebre/etiología , Mortalidad Hospitalaria , Humanos , Huésped Inmunocomprometido , Masculino , Persona de Mediana Edad , Diálisis Peritoneal , Prevalencia , Pronóstico , Diálisis Renal , Insuficiencia Renal Crónica/terapia , Índice de Severidad de la Enfermedad , Fumar/epidemiología , España/epidemiología , SobrevivientesRESUMEN
INTRODUCTION: Early graft loss is a devastating kidney transplant complication associated with high mortality and an increased risk of sensitization to antigens from the failed graft. Moreover, if rapid re-transplantation were to occur, given that the human leukocyte antigen antibodies identification may not be reliable until several weeks after transplantation, the recipient's immunological status would be uncertain. Hence, there could be an increased immunological risk. To date, there is no information on whether a rapid re-transplantation after early graft loss, without a new reliable anti-HLA determination, is safe. METHODS: We retrospectively analysed the number of rejections and the graft survival of re-transplanted patients with early graft loss (defined as graft failure before 30 days from transplant) from our centre between June 2003 and November 2019. The studied population was divided into rapid re-transplantation (performed within 30 days of early graft loss) and late re-transplantation (performed beyond those 30 days). RESULTS: Forty-seven patients were re-transplanted after early graft loss. There were nine rapid re-transplantation cases with an 89% five-year graft survival and one antibody-mediated rejection episode. Furthermore, we identified 38 cases of late re-transplantation with a 69% five-year graft survival, 4 T cell-mediated, and 11 antibody-mediated rejections. CONCLUSIONS: Rapid re-transplantation appears to be safe and does not entail increased rejection risk, nor does it impact long-term graft survival when compared to late re-transplantation.
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Rechazo de Injerto/cirugía , Supervivencia de Injerto , Fallo Renal Crónico/cirugía , Trasplante de Riñón/efectos adversos , Complicaciones Posoperatorias/epidemiología , Adulto , Anciano , Femenino , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/epidemiología , Prueba de Histocompatibilidad , Humanos , Fallo Renal Crónico/diagnóstico , Fallo Renal Crónico/epidemiología , Masculino , Persona de Mediana Edad , Selección de Paciente , Reoperación/efectos adversos , Estudios Retrospectivos , Factores de Tiempo , Resultado del TratamientoAsunto(s)
Anemia , Infecciones por Parvoviridae , Parvovirus B19 Humano , Insuficiencia Renal Crónica , Anemia/diagnóstico , Anemia/etiología , Humanos , Infecciones por Parvoviridae/complicaciones , Infecciones por Parvoviridae/diagnóstico , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/diagnósticoAsunto(s)
Amiloidosis de Cadenas Ligeras de las Inmunoglobulinas , Trasplante de Riñón , Donadores Vivos , Anciano , Femenino , Humanos , Amiloidosis de Cadenas Ligeras de las Inmunoglobulinas/sangre , Amiloidosis de Cadenas Ligeras de las Inmunoglobulinas/cirugía , Masculino , Persona de Mediana Edad , Terapia de Reemplazo RenalRESUMEN
The following paper reports the case of a woman on in-center hemodialysis through an arteriovenous graft, who attended with an acute vascular access thrombosis. Post percutaneous thrombectomy, the patient presented a rare case of self-limited acute hepatitis secondary to the revascularization procedure. We explain the probable trigger for this complication, its pathophysiology, management, and evolution.
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Derivación Arteriovenosa Quirúrgica , Hepatitis , Trombosis , Femenino , Humanos , Oclusión de Injerto Vascular/diagnóstico por imagen , Oclusión de Injerto Vascular/etiología , Oclusión de Injerto Vascular/cirugía , Grado de Desobstrucción Vascular , Derivación Arteriovenosa Quirúrgica/efectos adversos , Trombectomía/efectos adversos , Trombosis/diagnóstico por imagen , Trombosis/etiología , Trombosis/cirugía , Diálisis Renal/efectos adversos , Hepatitis/complicaciones , Resultado del Tratamiento , Estudios RetrospectivosRESUMEN
BACKGROUND: Cardiovascular disease is the major cause of death in patients with type 1 diabetes. Of the available risk predictors for this population, the Steno Type 1 Risk Engine (STENO T1) is the only one that includes kidney function as a risk factor, which is a well-described independent risk factor for cardiovascular disease. METHODS: We explore how simultaneous pancreas-kidney transplantation (SPKT) modifies the predicted cardiovascular risk by the STENO T1 through a retrospective study including recipients of a first SPKT between 2000 and 2016. RESULTS: Two hundred sixty-eight SPKT recipients with a mean age of 40 y old and a median follow-up of 10 y were included. Before transplantation, the expected incidence of cardiovascular events (CVEs) at 5 and 10 y according to STENO T1 would have been 31% and 50%, respectively, contrasting with an actual incidence of 9.3% and 16% for the same timepoints, respectively (P < 0.05). These differences were attenuated when STENO T1 was recalculated assuming 12th-mo glomerular filtration rate (at 5 and 10 y predicted CVE incidence was 10.5% and 19.4%, respectively). Early pancreas graft failure (hazard ratio [HR] 3.00, 95% confidence interval [CI], 1.14-7.88; P = 0.02) was an independent risk factor for post-SPKT CVE, alongside kidney graft failure (HR 2.90, 95% CI, 1.53-5.48; P = 0.001), and diabetes duration (HR 1.04, 95% CI, 1.00-1.09, P = 0.04). CONCLUSIONS: SPKT decreases in more than two-thirds of the predicted cardiovascular risk by the STENO T1. A functioning pancreas graft further reduces CVE risk, independently of kidney graft function.
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Enfermedades Cardiovasculares , Diabetes Mellitus Tipo 1 , Trasplante de Riñón , Trasplante de Páncreas , Adulto , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/etiología , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/cirugía , Factores de Riesgo de Enfermedad Cardiaca , Humanos , Trasplante de Riñón/efectos adversos , Páncreas , Trasplante de Páncreas/efectos adversos , Estudios Retrospectivos , Factores de RiesgoRESUMEN
Herpes virus infections is not uncommon in solid organ transplantation patients. We report 3 cases with primary Herpes simplex virus type-1 (HSV1) infection with acute liver failure (ALF). This is a rare and potentially fatal entity that could be a donor-derived infection. Although the initial clinical presentation is non-specific, it should be considered as a differential diagnosis in HSV-negative serology patients with liver failure and empirical treatment must be started in combination with a drastic reduction of immunosuppression. A strategy of HSV prophylaxis for pre-transplant HSV seronegative patients must be stablished in order to reduce the risk of clinical disease.
RESUMEN
INTRODUCTION: Given the increased COVID-19 observed in kidney transplant recipients (KTRs) and haemodialysis patients, several studies have tried to establish the efficacy of mRNA vaccines in these populations by evaluating their humoral and cellular responses. However, there is currently no information on clinical protection (deaths and hospitalizations), a gap that this study aims to fill. METHODS: Observational prospective study involving 1,336 KTRs and haemodialysis patients from three dialysis units affiliated to Hospital Clínic of Barcelona, Spain, vaccinated with two doses of mRNA-1273 (Moderna) or BNT162b2 (Pfizer-BioNTech) SARS-CoV-2 mRNA vaccines. The outcomes measured were SARS-CoV-2 infection diagnosed by a positive RT-PCR fourteen days after the second vaccine dose, hospital admissions derived from infection, and a severe COVID-19 composite outcome, defined as either ICU admission, invasive and non-invasive mechanical ventilation, or death. RESULTS: Six per cent (18/302) of patients on haemodialysis were infected, of whom four required hospital admission (1.3%), only one (0.3%) had severe COVID-19, and none of them died. In contrast, 4.3% (44/1034) of KTRs were infected, and presented more hospital admissions (26 patients, 2.5%), severe COVID-19 (11 patients, 1.1%) or death (4 patients, 0.4%). KTRs had a significantly higher risk of hospital admission than HD patients, and this risk increased with age and male sex (HR 3.37 and 4.74, respectively). CONCLUSIONS: The study highlights the need for booster doses in KTRs. In contrast, the haemodialysis population appears to have an adequate clinical response to vaccination, at least up to four months from its administration.
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COVID-19 , Trasplante de Riñón , Vacuna BNT162 , COVID-19/diagnóstico , COVID-19/epidemiología , COVID-19/prevención & control , Humanos , Incidencia , Trasplante de Riñón/efectos adversos , Masculino , Estudios Prospectivos , Diálisis Renal/efectos adversos , SARS-CoV-2RESUMEN
BACKGROUND: The number of octogenarians or older patients admitted to the intensive care unit (ICU) has been growing over the past several years. The aim of this study is to assess factors associated with acute renal replacement therapy (ARRT) requirement in these patients and the impact of this therapy on 90-day mortality. We also aimed to identify prognostic factors associated with mortality risk in the group of patients that required ARRT. METHODS: Retrospective study of octogenarian or older patients admitted to the ICU at Hospital Clínic de Barcelona from June 2007 to April 2019. Patients on chronic dialysis treatment or with a kidney transplant, and patients with limitation of therapeutic support or admitted for less than 48 h were excluded. RESULTS: 217 patients were included in the study, of whom 36.4% required ARRT. Use of vasoactive drugs (VAD) and Sequential Organ Failure Assessment (SOFA) score on admission were higher in ARRT patients (P = 0.009 and < 0.001, respectively). Basal estimated glomerular filtration rate (eGFR) was lower in the ARRT cohort (P < 0.001). Hospital and ICU length of stay were longer in the ARRT cohort (P < 0.001). Ninety-day mortality was 58.2% in the ARRT cohort compared to 55.8% in the non-ARRT control cohort (P = NS). In the survival analysis, only female sex, sepsis and non-renal SOFA ≥ 6.5 were significantly associated with mortality (P = 0.002, 0.028 and 0.009, respectively) in the ARRT cohort. CONCLUSION: Mortality was not significantly increased in the octogenarian or older population that required and received ARRT compared to control patients who did not require it. Severity scores like SOFA could help in the process of decision making about initiation of ARRT in this population.
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Lesión Renal Aguda , Enfermedad Crítica , Lesión Renal Aguda/diagnóstico , Lesión Renal Aguda/terapia , Anciano de 80 o más Años , Femenino , Humanos , Unidades de Cuidados Intensivos , Pronóstico , Terapia de Reemplazo Renal , Estudios RetrospectivosRESUMEN
Parvovirus B19 (PB19) is a common infection among solid transplant recipients. Usually, it is asymptomatic, but sometimes it can become a real therapeutic challenge. We report a case of a kidney transplant recipient with relapsing pure red cell aplasia due to PB19 infection. Our patient was initially managed with standard treatment consisting of intravenous immunoglobulins and minimization of immunosuppressive treatment. However, when this approach became ineffective, conversion from tacrolimus to everolimus was done, with favorable results. This paper explores infection by PB19 in kidney transplant recipients and the potential benefits of a calcineurin inhibitor-free immunosuppression and the antiviral properties of mTOR inhibitors.
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Anemia/virología , Eritema Infeccioso/complicaciones , Trasplante de Riñón , Receptores de Trasplantes , Enfermedad Crónica , Eritema Infeccioso/tratamiento farmacológico , Everolimus/uso terapéutico , Humanos , Recurrencia , Aplasia Pura de Células Rojas/virologíaRESUMEN
BACKGROUND: Acute kidney injury (AKI) is frequent in Coronavirus Infection Disease 2019 (COVID-19) patients. Factors associated with AKI in COVID-19 intensive care unit (ICU) patients and their outcomes have not been previously explored. METHODS: Prospective observational study of COVID-19 patients admitted to the ICUs of the Hospital Clínic of Barcelona (Spain), from March 25th to April 21st, 2020, who developed AKI stage 2 or higher (AKIN classification). The primary goal was to describe the characteristics of moderate-severe AKI of COVID-19 patients in an ICU context. As a secondary goal, we aimed to find independent predictors of AKI progression, Renal Replacement Therapy (RRT) requirement and mortality among these patients. RESULTS: During the study period, 52 out of 237 ICU patients, developed AKIN stage 2 or higher and were included in the study. A Sequential Organ Failure Assessment (SOFA) score at AKI diagnosis of 8 or higher was associated with RRT, OR 5.2, p 0.032. At the time of AKI diagnosis, patients had a worse liver profile and higher inflammation markers than at admission. Fifty per cent of the patients presented AKI progression from AKIN 2 to 3 and 28.85% required RRT. The use of corticosteroids in 69.2% of patients was associated with a reduced requirement of RRT, OR 0.13 (CI 95% 0.02-0.89), p 0.037. AKI was associated with high mortality (50%) and a longer hospital stay, median 35 vs 18 days (p 0.024). CONCLUSIONS: The prevalence of moderate/severe AKI in COVID-19 patients admitted to the ICU is high and has a strong correlation with mortality and length of hospital stay.
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Lesión Renal Aguda/etiología , COVID-19/complicaciones , Enfermedad Crítica , Terapia de Reemplazo Renal/métodos , Lesión Renal Aguda/diagnóstico , Lesión Renal Aguda/epidemiología , Anciano , COVID-19/epidemiología , Femenino , Estudios de Seguimiento , Mortalidad Hospitalaria/tendencias , Hospitalización/tendencias , Humanos , Incidencia , Unidades de Cuidados Intensivos/estadística & datos numéricos , Masculino , Pandemias , Estudios Prospectivos , Factores de Riesgo , SARS-CoV-2 , España/epidemiologíaRESUMEN
Blood flow (Qb) is one of the dialysis parameters most strongly influencing the performance of dialysis modalities. However, few studies have compared different dialysis modalities in patients with low Qb. We conducted a prospective, single-center study in 21 patients. Each patient underwent four dialysis sessions with routine dialysis parameters: high-flux hemodialysis (HD), predilution hemodiafiltration (pre-HDF), expanded HD (HDx), and postdilution HDF (post-HDF). The removal ratios (RR) of urea, creatinine, ß2 -microglobulin, myoglobin, prolactin, α1 -microglobulin, free kappa and lambda immunoglobulin light chains (kFLC and λFLC), α1 -acid glycoprotein, and albumin were compared intraindividually. A proportional part of the dialysate was collected to quantify albumin loss. There were no differences in urea and creatinine RRs. The ß2 -microglobulin RR was higher in pre-HDF and post-HDF. Myoglobin and prolactin RRs were higher with HDx and post-HDF. The α1 -microglobulin and α1 -acid glycoprotein RRs were significantly higher with post-HDF than with other treatments, and RRs obtained with HDx were higher than obtained with HD and pre-HDF. Free kFLC and λFLC RRs showed the following results in ascending order: HD, pre-HDF, HDx, and post-HDF, most of them with statistical significance. Albumin loss varied from 0.45 g with HD to 3.5 g with post-HDF. The global removal score values were 41.0 ± 4.8% with HD, 44.0 ± 5.2% with pre-HDF, 49.5 ± 4.6% with HDx, and 54.8 ± 5.3% with post-HDF, with significant differences between all treatment modalities. In conclusion, this study confirms the superiority of post-HDF over high-flux HD, pre-HDF, and HDx in patients with low Qb. HDx was the closest alternative to post-HDF and was clearly superior to HD and pre-HDF. Finally, pre-HDF was also superior to HD. With this Qb, there was a higher risk of underdialysis, both diffusive and convective, especially in patients with a session duration of less than 5 h.
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Fallo Renal Crónico/fisiopatología , Fallo Renal Crónico/terapia , Diálisis Renal/métodos , Adulto , Anciano , Anciano de 80 o más Años , Velocidad del Flujo Sanguíneo/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Resultado del TratamientoRESUMEN
INTRODUCTION: Recently, a new class of dialyzers, medium cut-off membranes (MCO), designed to improve the permeability, which could provide an efficacy similar to hemodiafiltration, have been incorporated into our therapeutic possibilities. To increase the knowledge about its use, the objective of the study was to evaluate the effect of the surface and blood flow (Qb) on the depurative efficacy in the MCO membranes. MATERIAL AND METHODS: We included 19 patients in the hemodialysis. Each patient received 6 sessions, in which the membrane surface was varied, from 1.7 to 2.0 m2, and/or the Qb (300, 350, 400 or 450mL/min). In each session, different solutes were determined at the beginning and end of dialysis. RESULTS: The surface change of the dialyzer did not show significant differences in the removal of small or large molecules, without changes in albumin loss. The increase in Qb was accompanied by an increase in clearance of small molecules, without showing differences in the percentage reduction of ß2-microglobulin, myoglobin, prolactin, α1-microglobulin and α1-acid glycoprotein, except for some comparison with Qb 450mL/min. There were also no differences in the loss of albumin in the dialysis fluid, less than 2.5 g in all situations. CONCLUSION: The increase of the surface area from 1.7 to 2.0 m2 in the MCO dialyzer has not meant a greater depurative effectiveness. In these dialyzers the increase of Qb does not seem to be as determinant as in hemodiafiltration except for the clearance of small molecules.
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Membranas Artificiales , Flujo Sanguíneo Regional , Diálisis Renal/instrumentación , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Propiedades de SuperficieRESUMEN
INTRODUCCIÓN: Recientemente, se ha incorporado a nuestras posibilidades terapéuticas una nueva clase de dializadores, las membranas de medio cut-off (MCO), diseñadas para mejorar la permeabilidad y que podrían alcanzar una eficacia similar a la hemodiafiltración. Para aumentar el conocimiento sobre su uso, el objetivo del estudio fue valorar en las membranas de MCO el efecto de la superficie y del flujo sanguíneo (Qb) sobre la eficacia depurativa. MATERIAL Y MÉTODOS: Se incluyó a 19 pacientes en programa de hemodiálisis. Cada paciente recibió 6 sesiones, en las que se varió la superficie de membrana, de 1,7 o 2,0 m2, y el Qb (300, 350, 400 o 450 mL/min). En cada sesión se determinaron diferentes solutos al inicio y al final de la diálisis. RESULTADOS: El cambio de superficie del dializador no mostró diferencias significativas en la depuración de pequeñas o grandes moléculas, sin cambios en la pérdida de albúmina. El aumento del Qb se acompañó de un aumento de depuración de pequeñas moléculas, sin mostrar diferencias en el porcentaje de reducción de β2-microglobulina, mioglobina, prolactina, α1-microglobulina y α1-glicoproteína ácida, a excepción de alguna comparación con Qb 450mL/min. Tampoco se observaron diferencias en la pérdida de albúmina en el líquido de diálisis, inferior a 2,5 g en todas las situaciones. CONCLUSIÓN: El incremento de la superficie de 1,7 a 2,0 m2 en el dializador de MCO no ha significado una mayor eficacia depurativa. En estos dializadores el aumento del Qb no parece ser tan determinante como en la hemodiafiltración, a excepción de la depuración de pequeñas moléculas
INTRODUCTION: Recently, a new class of dialyzers, medium cut-off membranes (MCO), designed to improve the permeability, which could provide an efficacy similar to hemodiafiltration, have been incorporated into our therapeutic possibilities. To increase the knowledge about its use, the objective of the study was to evaluate the effect of the surface and blood flow (Qb) on the depurative efficacy in the MCO membranes. MATERIAL AND METHODS: We included 19 patients in the hemodialysis. Each patient received 6 sessions, in which the membrane surface was varied, from 1.7 to 2.0 m2, and/or the Qb (300, 350, 400 or 450 mL/min). In each session, different solutes were determined at the beginning and end of dialysis. RESULTS: The surface change of the dialyzer did not show significant differences in the removal of small or large molecules, without changes in albumin loss. The increase in Qb was accompanied by an increase in clearance of small molecules, without showing differences in the percentage reduction of β2-microglobulin, myoglobin, prolactin, α1-microglobulin and α1-acid glycoprotein, except for some comparison with Qb 450 mL/min. There were also no differences in the loss of albumin in the dialysis fluid, less than 2.5 g in all situations. CONCLUSION: The increase of the surface area from 1.7 to 2.0 m2 in the MCO dialyzer has not meant a greater depurative effectiveness. In these dialyzers the increase of Qb does not seem to be as determinant as in hemodiafiltration except for the clearance of small molecules