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1.
J Vasc Access ; 24(3): 358-369, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-34392712

RESUMEN

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).


Asunto(s)
Derivación Arteriovenosa Quirúrgica , Nefrología , Humanos , Oclusión de Injerto Vascular/diagnóstico por imagen , Oclusión de Injerto Vascular/etiología , Oclusión de Injerto Vascular/terapia , Constricción Patológica , Derivación Arteriovenosa Quirúrgica/efectos adversos , Venas Braquiocefálicas , Diálisis Renal/efectos adversos
2.
Am J Transplant ; 21(11): 3573-3582, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34132037

RESUMEN

Liver transplantation (LT) is a complex operation that most transplant surgeons learn in fellowship. Training varies as there is lack of objective data that can be used to standardize teaching. We performed a retrospective review of our adult LT database with aim of looking at fellow's experience. Using American Society of Transplant Surgery cutoff of, at least 45 LT during fellowship, data for first 45 LT were compared to LT 45-90. Fellow's cases were also clustered in sequential groups of 15 LT and analyzed to estimate the learning curve (LC). Comparison of LT 1-45 with LT 46-90 showed significantly lower total operative times (TOT) (324 vs. 344 min) and warm ischemia times (WIT) (28 vs. 31 min) in the 45-90 group. Rates of biliary complications (23.8% vs. 16.4%) and bile leaks alone (10.3% vs. 5.5%) were significantly higher for first 45 LT. Analysis of fellows experience in sequential clusters of 15 LT showed decreasing TOT, WIT, biliary complications and rates of unplanned return to the OR with progression of fellowship. This study validates the current ASTS requirement of at least 45 LT. LC generated using these data can help individualize training and optimize outcomes through identification of areas in need of improvement.


Asunto(s)
Trasplante de Hígado , Adulto , Becas , Humanos , Curva de Aprendizaje , Donadores Vivos , Estudios Retrospectivos
3.
J Am Coll Surg ; 233(1): 111-118, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33836288

RESUMEN

BACKGROUND: The majority of liver transplantations (LTs) in North America are performed by transplant surgery fellows with attending surgeon supervision. Although a strict case volume requirement is mandatory for graduating fellows, no guidelines exist on providing constructive feedback to trainees during fellowship. STUDY DESIGN: A retrospective review of all adult LTs performed by abdominal transplant surgery fellows at a single American Society of Transplant Surgeons-accredited academic institution from 2005 to 2019 was conducted. Data from the most recent 5 fellows were averaged to generate reference learning curves for 8 variables representing operative efficiency (ie total operative time, warm ischemia time, and cold ischemia time) and surgical outcomes (ie intraoperative blood loss, unplanned return to the operating room, biliary complication, vascular complication, and patient/graft loss). Data for newer fellows were plotted against the reference curves at 3-month intervals to provide an objective assessment measure. RESULTS: Three hundred and fifty-two adult LTs were performed by 5 fellows during the study period. Mean patient age was 56 years; 67% were male; and mean Model for End-Stage Liver Disease score at transplantation was 22. For the 8 primary variables, mean values included the following: total operative time 330 minutes, warm ischemia time 28 minutes, cold ischemia time 288 minutes, intraoperative blood loss 1.59 L, biliary complication 19.6%, unplanned return to operating room 19.3%, and vascular complication 2.3%. A structure for feedback to fellows was developed using a printed report card and through in-person meetings with faculty at 3-month intervals. CONCLUSIONS: Comparative feedback using institution-specific reference curves can provide valuable objective data on progression of individual fellows. It can aid in the timely identification of areas in need of improvement, which enhances the quality of training and has the potential to improve patient care and transplantation outcomes.


Asunto(s)
Competencia Clínica , Evaluación Educacional , Becas/normas , Fallo Hepático/cirugía , Trasplante de Hígado/educación , Trasplante de Hígado/normas , Adulto , Competencia Clínica/normas , Eficiencia , Retroalimentación Formativa , Humanos , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento
4.
J Vasc Access ; 22(3): 417-423, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-32729767

RESUMEN

INTRODUCTION: The volume of blood flowing through the vascular access is an important parameter necessary to provide adequate dialysis for a functional arteriovenous fistula. Higher blood flows are seen in arteriovenous access that receive inflow from larger arteries such as brachial or axillary compared to those based on medium-caliber radial or ulnar arteries. We hypothesized that an anatomic difference in the length and the diameter of the artery is an important determinant of the flow volume in arteriovenous fistula created at different anatomic locations. METHODS: Using computational fluid dynamics, we evaluated the contribution of the length and diameter of inflow artery on simulations performed with geometric models constructed to represent arteriovenous fistula circuits. Lengths and diameters of the inflow artery were altered to mimic arteriovenous fistula created at various locations of the upper extremity with standard and variant anatomy. RESULTS: Models of arteriovenous fistula created with variable lengths and diameters of the inflow artery suggest that the length of the vessel has an inverse linear relationship and the diameter has a direct linear relationship to flow volume. CONCLUSION: Computational fluid dynamic modeling of arteriovenous fistula can be used to understand the physiologic basis of clinical observations of function. Evaluation of the effect of inflow artery length and diameter helps explain the higher flows seen in arteriovenous fistula created using large caliber arteries for inflow. Computational fluid dynamic modeling helps operators understand the contributions of inflow artery in access function and can guide anastomotic site selection.


Asunto(s)
Arterias/fisiología , Derivación Arteriovenosa Quirúrgica , Modelos Cardiovasculares , Arterias/anatomía & histología , Arterias/cirugía , Velocidad del Flujo Sanguíneo , Simulación por Computador , Humanos , Hidrodinámica , Flujo Sanguíneo Regional
5.
Am J Kidney Dis ; 75(4 Suppl 2): S1-S164, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32778223

RESUMEN

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.


Asunto(s)
Fallo Renal Crónico/terapia , Nefrología , Diálisis Renal/normas , Sociedades Médicas , Dispositivos de Acceso Vascular/normas , Humanos
6.
Int J Surg ; 78: 149-153, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32335240

RESUMEN

INTRODUCTION: Incisional hernias (IH) develop in up to 40% of liver transplant (LT) recipients and can contribute to considerable morbidity. MATERIALS AND METHODS: A single center retrospective review of a prospectively maintained LT database was conducted to identify all patients diagnosed with IH after LT during a 13-year study period (2003-2015). Analyzed data included patient demographics, LT details, incidence and timing of IH, risk factors, management strategies and long-term outcomes. RESULTS: During the 13-year study period, IH was diagnosed in 16.7% (163/976) of LT recipients after a median of 19.6 months (range 6.7-49.5 months) from transplant surgery. Identified risk factors for developing IH included male gender (p < 0.001) while acute cellular rejection (ACR) was found to be negatively associated with the risk of developing IH (p = 0.014). Acute incarceration/strangulation was seen in 4 patients with IH while the remaining (n = 159) presented with non-emergent symptoms. Surgical repair was undertaken in 70/163 (43%) IH patients after medical optimization when possible (open repair 83%, mesh use 90%). IH recurrence rate was 14.3% (10/70) with comparable rates in no-mesh and with-mesh repairs (42.9% vs. 11.3%; p = 0.057) and open (15.8%) and laparoscopic (9.1%) approaches (p = 0.68). CONCLUSION: IH is a late complication following LT and male gender is a consistent predictive marker. Acute presentation is infrequent and elective repair can be planned in most patients allowing for risk factor optimization to ensure promising long-term outcomes.


Asunto(s)
Hernia Incisional/etiología , Trasplante de Hígado/efectos adversos , Adulto , Anciano , Femenino , Humanos , Hernia Incisional/cirugía , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo
7.
Int J Surg ; 75: 84-90, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32014598

RESUMEN

INTRODUCTION: Direct-acting antivirals (DAA's) have revolutionized hepatitis-C virus (HCV) treatment, however controversy remains regarding timing of treatment in relation to liver-transplant (LT). METHODS: Single-center retrospective study assessing outcomes of listed HCV positive patients in the DAA-era (2014-2017). Patients treated with DAA's before LT (DAA pre-LT) were compared to those who were not treated before LT (No DAA pre-LT) RESULTS: 156 HCV positive patients were listed during study-period; 104 (67%) underwent LT while 52 (33%) were de-listed. Of transplanted patients, 48 (46%) received DAA pre-LT while 56 (54%) were treated post-LT. Both groups were comparable in age, gender, MELD, patient and graft survival and cure-rates (98% in DAA pre-LTvs.95% in No DAA pre-LT; p > 0.05). DAA pre-LT group required higher number of treatments-per-patient to clear virus (1.46vs.1.06; p = 0.0006), spent more time on waitlist (331d.vs150d; p = 0.0040) and were less likely to receive livers from HCV positive donors (6%vs.25%; p = 0.0148). Twenty-nine (56%) of the 52 delisted received DAA. They had lower listing-MELD (12vs.18; p = 0.0033), and were more likely to be delisted for "condition improved" (34%vs.4%; p = 0.0143) compared to the 23 (44%) delisted patients who did not receive DAA's. CONCLUSIONS: DAA's were equally effective in clearing HCV in listed patients irrespective of timing. DAA pre-LT can disadvantage some patients through increase number of treatments needed and longer waitlist times, but treatment in some listed patients with low-MELD can improve condition and alleviate need for LT.


Asunto(s)
Antivirales/uso terapéutico , Hepatitis C/cirugía , Trasplante de Hígado , Anciano , Femenino , Hepatitis C/tratamiento farmacológico , Humanos , Trasplante de Hígado/mortalidad , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Listas de Espera
8.
J Vasc Access ; 21(5): 543-553, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31884872

RESUMEN

Although not common, hemodialysis access-induced distal ischemia is a serious condition resulting in significant hemodialysis patient morbidity. Patients with signs and symptoms suggestive of hand ischemia frequently present to the general and interventional nephrologist for evaluation. In order to care for these cases, it is necessary to understand this syndrome and its management. Most cases can be managed conservatively without intervention. Some cases requiring intervention may be treated using techniques within the scope of practice of the interventional nephrologists while other cases require vascular surgery. In order for the interventional nephrologists to evaluate and manage these cases in a timely and appropriate manner, practice guidelines are presented.


Asunto(s)
Derivación Arteriovenosa Quirúrgica/efectos adversos , Implantación de Prótesis Vascular/efectos adversos , Mano/irrigación sanguínea , Isquemia/terapia , Nefrólogos/normas , Pautas de la Práctica en Medicina/normas , Radiografía Intervencional/normas , Radiólogos/normas , Diálisis Renal/normas , Circulación Colateral , Consenso , Humanos , Isquemia/diagnóstico por imagen , Isquemia/etiología , Isquemia/fisiopatología , Radiografía Intervencional/efectos adversos , Flujo Sanguíneo Regional , Factores de Riesgo , Resultado del Tratamiento
9.
Transplantation ; 104(2): 343-348, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31283685

RESUMEN

BACKGROUND: More people who have personally consented to organ donation via first person authorization (FPA) registration before death become organ donors than those not personally consenting. The majority of registrations occur at state-specific department of motor vehicle (DMV) and licensing offices, where people register their vehicles and obtain driver's licenses. METHODS: One organ procurement organization (OPO) ran 3 DMV offices and implemented an intervention: a donor-centric approach, including employee education, office decoration with donation materials, and customer experience improvements. Data about registry enrollment was collected before and during the 4-year OPO licensing office contract. A linear mixed model and interrupted time series analyses were performed to evaluate whether the intervention improved rates of registration. RESULTS: Preintervention registry enrollment rates per month were 10%-50%. Having the offices run by an OPO was associated with more enrollments independent of the increasing trend of enrollment (P < 0.001). Also, the DMV office with the lowest preimplementation registration rates had an immediate increase in enrollments after the intervention leading to higher registration rates (P < 0.001). CONCLUSIONS: A donor-centric OPO-managed DMV experience increases FPA registration, especially at offices with low initial registration rates. However, even at the office with the highest percentage of FPA registrations, rates were only 65% at intervention conclusion. The transplant community should consider other opportunities for FPA registration.


Asunto(s)
Vehículos a Motor/legislación & jurisprudencia , Trasplante de Órganos/tendencias , Sistema de Registros , Donantes de Tejidos/provisión & distribución , Obtención de Tejidos y Órganos/organización & administración , Humanos , Estados Unidos
10.
J Vasc Access ; 20(2): 114-122, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30101672
11.
Int J Surg ; 53: 339-344, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29654968

RESUMEN

BACKGROUND: Increasing use of Living Donor Kidney Transplantation (LDKT) would decrease the discrepancy between patients awaiting transplantation and organ availability. Minimally invasive surgical approaches attempt to improve outcomes and foster living donation. This report compares outcomes of open minimal incision nephrectomy (Mini N) and a hand assisted laparoscopic nephrectomy (HALN). METHODS: This is a retrospective analysis of a prospectively maintained clinical database of LDKT using HALN or Mini N at a single institution between July 2007 and December 2015. Donor and recipient demographics, relevant pre-, intra- and post-operative factors, outcomes such as patient and graft survival rates, and complications were evaluated. RESULTS: Four hundred and fifty-four adult LDKT (243 Mini N, 211 HALN) were performed during the study period. Recipient and donor demographics were comparable except for higher BMI (p = 0.027) in HALN donors. One-, 3- and 5-year patient and graft survival rates were comparable. Six HALN donors experienced infectious wound complications or superficial skin dehiscence; none did in the Mini N group (p = 0.009). Eight HALN donors and one Mini N donor required an incisional hernia repair (p = 0.014). Recipients had similar warm ischemia times (33 v. 35 min, p = 0.491), but recipient surgeons of HALN nephrectomies subjectively noted higher anastomotic difficulty (10.4% v. 4.5%, p = 0.0183). Other parameters were similar between groups. CONCLUSION: Both Mini N and HALN provide similar long term recipient and donor outcomes. Offering techniques such as Mini N and HALN for living donor kidney procurement facilitates the opportunity to provide living donors safer and better tolerated nephrectomy procedures.


Asunto(s)
Laparoscópía Mano-Asistida , Trasplante de Riñón , Donadores Vivos , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Nefrectomía/métodos , Adulto , Estudios de Cohortes , Femenino , Humanos , Masculino , Complicaciones Posoperatorias , Estudios Retrospectivos
14.
J Am Coll Surg ; 226(4): 484-494, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29360615

RESUMEN

BACKGROUND: Biliary complications (BCs) affect up to to 34% of liver transplant recipients and are a major source of morbidity and cost. This is a 13-year review of BCs after liver transplantation (LT) at a tertiary care center. STUDY DESIGN: We conducted a single-center retrospective review of our prospective database to assess BCs in adult (aged 18 years or older) liver transplant recipients during a 13-year period (2002 to 2014). Biliary complications were divided into 3 subgroups: leak alone (L), stricture alone (S), and both leak and strictures (LS). Controls (no BCs) were used for comparison. RESULTS: There were 1,041 adult LTs performed during the study period; BCs developed in 239 (23%) of these patients: 55 (23%) L, 148 (62%) S, and 36 (15%) LS. One hundred and two (43%) were early (less than 30 d). Surgical revision was required in 42 cases (17%) (30 L, 10 LS, and 2 S), while the remaining 197 (83%) were managed nonsurgically (25 L, 26 LS, and 146 S), with a mean of 4.2 interventions/patient. One-, 3-, and 5-year overall patient and graft survival was significantly reduced in patients with bile leaks (84%, 71%, and 68% and 76%, 67%, and 64%, respectively) compared with controls (90%, 84%, and 78% and 88%, 81%, and 76%, respectively [p < 0.05]). Patients with BCs had higher incidence of cholestatic liver disease, higher pre-LT bilirubin, higher use of T-tubes, higher use of donor after cardiac death grafts, and higher rates of acute rejection (p < 0.05). Patients with BCs had longer ICU and hospital stays and higher rates of 30- and 90-day readmissions (p < 0.01). Multivariate analysis identified cholestatic liver disease, Roux-en-Y anastomosis, donor risk index >2, and T-tubes as independent BC predictors. CONCLUSIONS: Biliary complications after LT can significantly decrease patient and graft survival rates. Careful donor and recipient selection and attention to anastomotic technique can reduce BCs and improve outcomes.


Asunto(s)
Enfermedades de las Vías Biliares/epidemiología , Fallo Hepático/mortalidad , Fallo Hepático/cirugía , Trasplante de Hígado/efectos adversos , Complicaciones Posoperatorias/epidemiología , Adulto , Enfermedades de las Vías Biliares/diagnóstico , Femenino , Supervivencia de Injerto , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/diagnóstico , Estudios Retrospectivos , Tasa de Supervivencia , Centros de Atención Terciaria
15.
Clin J Am Soc Nephrol ; 13(3): 495-500, 2018 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-28729382

RESUMEN

Central venous catheters are used frequently in patients on hemodialysis as a bridge to a permanent vascular access. They are prone to frequent complications, including catheter-related bloodstream infection, catheter dysfunction, and central vein obstruction. There is a compelling need to develop new drugs or devices to prevent central venous catheter complications. We convened a multidisciplinary panel of experts to propose standardized definitions of catheter end points to guide the design of future clinical trials seeking approval from the Food and Drug Administration. Our workgroup suggests diagnosing catheter-related bloodstream infection in catheter-dependent patients on hemodialysis with a clinical suspicion of infection (fever, rigors, altered mental status, or unexplained hypotension), blood cultures growing the same organism from the catheter hub and a peripheral vein (or the dialysis bloodline), and absence of evidence for an alternative source of infection. Catheter dysfunction is defined as the inability of a central venous catheter to (1) complete a single dialysis session without triggering recurrent pressure alarms or (2) reproducibly deliver a mean dialysis blood flow of >300 ml/min (with arterial and venous pressures being within the hemodialysis unit parameters) on two consecutive dialysis sessions or provide a Kt/V≥1.2 in 4 hours or less. Catheter dysfunction is defined only if it persists, despite attempts to reposition the patient, reverse the arterial and venous lines, or forcefully flush the catheter. Central vein obstruction is suspected in patients with >70% stenosis of a central vein by contrast venography or the equivalent, ipsilateral upper extremity edema, and an existing or prior history of a central venous catheter. There is some uncertainty about the specific criteria for these diagnoses, and the workgroup has also proposed future high-priority studies to resolve these questions.


Asunto(s)
Obstrucción del Catéter , Infecciones Relacionadas con Catéteres/diagnóstico , Catéteres de Permanencia/efectos adversos , Catéteres Venosos Centrales/efectos adversos , Determinación de Punto Final , Enfermedades Vasculares/diagnóstico , Infecciones Relacionadas con Catéteres/etiología , Ensayos Clínicos como Asunto , Humanos , Diálisis Renal
16.
Clin J Am Soc Nephrol ; 13(3): 501-512, 2018 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-28729383

RESUMEN

This paper is part of the Clinical Trial Endpoints for Dialysis Vascular Access Project of the American Society of Nephrology Kidney Health Initiative. The purpose of this project is to promote research in vascular access by clarifying trial end points which would be best suited to inform decisions in those situations in which supportive clinical data are required. The focus of a portion of the project is directed toward arteriovenous access. There is a potential for interventional studies to be directed toward any of the events that may be associated with an arteriovenous access' evolution throughout its life cycle, which has been divided into five distinct phases. Each one of these has the potential for relatively unique problems. The first three of these correspond to three distinct stages of arteriovenous access development, each one of which has been characterized by objective direct and/or indirect criteria. These are characterized as: stage 1-patent arteriovenous access, stage 2-physiologically mature arteriovenous access, and stage 3-clinically functional arteriovenous access. Once the requirements of a stage 3-clinically functional arteriovenous access have been met, the fourth phase of its life cycle begins. This is the phase of sustained clinical use from which the arteriovenous access may move back and forth between it and the fifth phase, dysfunction. From this phase of its life cycle, the arteriovenous access requires a maintenance procedure to preserve or restore sustained clinical use. Using these definitions, clinical trial end points appropriate to the various phases that characterize the evolution of the arteriovenous access life cycle have been identified. It is anticipated that by using these definitions and potential end points, clinical trials can be designed that more closely correlate with the goals of the intervention and provide appropriate supportive data for clinical, regulatory, and coverage decisions.


Asunto(s)
Derivación Arteriovenosa Quirúrgica , Determinación de Punto Final , Mano/irrigación sanguínea , Isquemia/diagnóstico , Injerto Vascular , Venas/patología , Aneurisma/diagnóstico , Aneurisma/etiología , Derivación Arteriovenosa Quirúrgica/efectos adversos , Ensayos Clínicos como Asunto , Constricción Patológica/etiología , Humanos , Infecciones/diagnóstico , Infecciones/etiología , Isquemia/etiología , Diálisis Renal , Trombosis/diagnóstico , Trombosis/etiología , Injerto Vascular/efectos adversos
17.
Transpl Immunol ; 45: 42-47, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28911876

RESUMEN

BACKGROUND: Immune responses to tissue-restricted self-antigens are thought to play a role in chronic rejection after solid organ transplantation. De novo development of antibodies (Abs) to vimentin have been reported to be associated with interstitial fibrosis/tubular atrophy after kidney transplant, and it has been suggested that immunoglobulin isotype switching of Abs to vimentin may occur during this process. We aimed to determine the correlation between immunoglobulin isotype switching of Abs to vimentin and development of transplant glomerulopathy (TG) after kidney transplant, and to determine whether citrullinated modification of vimentin is required for de novo anti-vimentin development. METHODS: Sera were collected from 24 patients with TG (diagnosed on biopsy), 24 matched stable kidney transplant recipients (KTxRs) and 22 normal healthy subjects who did not undergo transplant. Serum vimentin Abs concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Immunoglobulin isotypes of anti-vimentin were determined using isotype-specific Abs conjugated with horseradish peroxidase. Samples were considered positive to vimentin Abs if the values were above mean+2× standard deviations of the levels in the healthy control subjects. Specificities of anti-vimentin for mutated citrullinated vimentin and anti-mutated citrullinated vimentin were measured by ELISA. RESULTS: In this retrospective analysis of 24 KTxRs with TG, 16/24 (67%) patients with biopsy-proven TG developed Abs to vimentin (645±427ng/ml). In contrast, only 4/24 (17%) stable KTxRs had detectable Abs to vimentin (275±293ng/ml; p=0.001). Of the patients with TG, 15/24 (63%) developed Abs to vimentin of IgG isotype (572±276ng/ml), whereas only 6/24 (25%) stable KTxRs (310±288ng/ml) had anti-vimentin of IgG isotype (p=0.002). However, no significant difference was noted in the concentration of IgM isotype anti-vimentin between KTxRs with TG (9/24 [38%], 407±401ng/ml) and stable KTxRs (5/24 [21%], 348±439ng/ml; p=0.631). The serum concentration of Abs specific for the mutated form of citrullinated vimentin was not significantly different between KTxRs with TG and stable KTxRs. CONCLUSIONS: Patients with biopsy-proven TG demonstrated significantly increased levels of anti-vimentin Abs of the IgG isotype compared with stable KTxRs. Anti-vimentin in stable KTxRs was primarily of IgM isotype. Therefore, the observed isotype switching of anti-vimentin from IgM to IgG isotype strongly suggests ongoing immune responses to vimentin in KTxRs diagnosed with TG. Furthermore, as opposed to patients with rheumatoid arthritis (who develop immune responses primarily to citrullinated vimentin), KTxRs diagnosed with TG developed immune responses to non-citrullinated vimentin, suggesting that modification of vimentin protein via citrullination is not required for the de novo anti-vimentin response seen in patients with TG.


Asunto(s)
Autoanticuerpos/sangre , Trasplante de Riñón , Vimentina/inmunología , Adulto , Ensayo de Inmunoadsorción Enzimática , Femenino , Glomerulonefritis Membranosa , Rechazo de Injerto , Supervivencia de Injerto/inmunología , Humanos , Cambio de Clase de Inmunoglobulina , Masculino , Persona de Mediana Edad , Especificidad de Órganos , Estudios Retrospectivos
18.
J Vasc Access ; 18(6): 515-521, 2017 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-28777403

RESUMEN

INTRODUCTION: Functional arteriovenous fistula (AVF) is the best vascular access for end-stage renal disease patients. AVF maturation is variable and many require additional interventions to achieve functionality. Long-term benefits of such interventions are unclear. Using a protocol for AVF planning, creation, maturation evaluation and performing interventions based on objective findings along with maintaining a database on follow-up is necessary to evaluate this question.The aim of this study is to evaluate the long-term outcome of newly constructed AVFs using a protocol-based approach in a tertiary care academic center. METHODS: This is an observational study. Long-term outcomes of consecutive AVFs placed over a 5-year period using a protocol for creation, maturation evaluation and interventions based on objective findings were analyzed using a prospectively maintained clinical database. RESULTS: Functioning AVFs were achieved in 86.5% (n = 296) of 342 patients. Primary and secondary patency of 372 AVF procedures at 12, 24 and 60 months were 42.8%, 31.6% and 20.8%; and 81.8%, 77.6% and 71.7%, respectively. Functional patency at 12, 24 and 60 months were 95.1%, 88.7%, and 85.2%, respectively. Long-term function was similar for AVFs maturing with ≤4 interventions and without interventions. AVFs maturing with 2-4 interventions needed significantly more interventions to maintain long-term functional patency (p = 0.003). CONCLUSIONS: Piggyback straight-line on-lay technique (pSLOT) improves early outcome providing opportunity to identify other problems contributing to non-maturation. A large number of AVFs needing planned interventions to mature provide good long-term function. Establishing process of care guidelines for creation and follow-up has a potential to improve AVF outcome.


Asunto(s)
Derivación Arteriovenosa Quirúrgica/métodos , Fallo Renal Crónico/terapia , Diálisis Renal , Extremidad Superior/irrigación sanguínea , Adulto , Anciano , Derivación Arteriovenosa Quirúrgica/efectos adversos , Bases de Datos Factuales , Femenino , Estudios de Seguimiento , Oclusión de Injerto Vascular/etiología , Oclusión de Injerto Vascular/fisiopatología , Oclusión de Injerto Vascular/terapia , Humanos , Estimación de Kaplan-Meier , Fallo Renal Crónico/diagnóstico , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Missouri , Factores de Riesgo , Centros de Atención Terciaria , Factores de Tiempo , Resultado del Tratamiento , Grado de Desobstrucción Vascular
19.
Clin Transplant ; 31(8)2017 08.
Artículo en Inglés | MEDLINE | ID: mdl-28639386

RESUMEN

Simultaneous kidney-pancreas transplantation (SKP Tx) is a treatment for end-stage kidney disease secondary to diabetes mellitus. We investigated the role of immune responses to donor human leukocyte antigens (HLA) and tissue-restricted kidney and pancreas self-antigens (KSAgs and PSAgs, respectively) in SKP Tx recipients (SKP TxRs). Sera collected from 39 SKP TxRs were used to determine de novo Abs specific for KSAgs (collagen-IV, Col-IV; fibronectin, FN) and PSAgs (insulin, islet cells, glutamic acid decarboxylase, and pancreas-associated protein-1) by ELISA. KSAg-specific IFN-γ, IL-17, and IL-10 cytokines were enumerated by ELISpot. Abs to donor HLA classes I and II were determined by Luminex assay. Abs to KSAgs and PSAgs were detectable in recipients with rejection compared with stable recipients (P<.05). Kidney-only rejection recipients had increased Abs against KSAgs compared with stable (P<.05), with no increase in Abs against PSAgs. Pancreas-only rejection recipients showed increased Abs against PSAgs compared to stable (P<.05), with no Abs against KSAgs. SKP TxRs with rejection showed increased frequencies of KSAg-specific IFN-γ and IL-17 with reduction in IL-10-secreting cells. SKP TxRs with rejection developed Abs to KSAgs and PSAgs demonstrated increased frequencies of kidney or pancreas SAg-specific IFN-γ and IL-17-secreting cells with reduced IL-10, suggesting loss of peripheral tolerance to SAgs.


Asunto(s)
Autoanticuerpos/sangre , Autoantígenos/inmunología , Rechazo de Injerto/inmunología , Trasplante de Riñón , Trasplante de Páncreas , Adulto , Biomarcadores/sangre , Citocinas/inmunología , Ensayo de Inmunoadsorción Enzimática , Femenino , Estudios de Seguimiento , Rechazo de Injerto/sangre , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/epidemiología , Supervivencia de Injerto/inmunología , Antígenos HLA/inmunología , Humanos , Incidencia , Isoanticuerpos/sangre , Trasplante de Riñón/métodos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Trasplante de Páncreas/métodos
20.
J Vasc Access ; 18(Suppl. 1): 1-4, 2017 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-28297045

RESUMEN

Over the past 50 years, since Dr. Appel performed the first internal vascular access procedure for hemodialysis, the distal radiocephalic arteriovenous fistula continues to be the access of choice. Over time, failure to maturation has evolved as a major problem associated with this procedure depriving its benefits to many patients with end-stage renal disease. A variable incidence of this problem within similar patients suggests that surgical technique may play an important role in the development of non-maturation. Evaluating the current surgical techniques based on the hemodynamic consequences of anatomic and physiologic alterations following this procedure highlights the role of surgical technique in mitigating or reducing complications. Piggy-back straight line on-lay, a technique that helps to tailor the blood flow and reduce the oscillatory shear stress appears to reduce the incidence of early juxta-anastomotic problems, which contribute significantly to the problem of non-maturation.


Asunto(s)
Derivación Arteriovenosa Quirúrgica/métodos , Arteria Radial/cirugía , Diálisis Renal , Extremidad Superior/irrigación sanguínea , Venas/cirugía , Derivación Arteriovenosa Quirúrgica/efectos adversos , Velocidad del Flujo Sanguíneo , Oclusión de Injerto Vascular/etiología , Oclusión de Injerto Vascular/fisiopatología , Humanos , Arteria Radial/fisiopatología , Flujo Sanguíneo Regional , Reimplantación , Factores de Riesgo , Resultado del Tratamiento , Grado de Desobstrucción Vascular , Venas/fisiopatología
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