Diagnostic accuracy of ultrasound dilution access blood flow measurement in detecting stenosis and predicting thrombosis in native forearm arteriovenous fistulae for hemodialysis.

BACKGROUND: Vascular access surveillance by ultrasound dilution blood flow rate (Qa) measurement is widely recommended; however, optimal criteria for detecting stenosis and predicting thrombosis in arteriovenous fistulae (AVFs) are still not clearly defined. METHODS: In a blinded trial, we evaluated the accuracy of single Qa measurement, Qa adjusted for mean arterial pressure (Qa/MAP), and decrease in Qa over time (dQa) in detecting stenosis and predicting thrombosis in an unselected population of 120 hemodialysis subjects with native forearm AVFs (91 AVFs, located at the wrist; 29 AVFs, located at the midforearm). All AVFs underwent fistulography, which identified greater than 50% stenosis in 54 cases. RESULTS: Receiver operating characteristic curve analysis showed that dQa, Qa, and Qa/MAP have a high stenosis discriminative ability with similar areas under the curve (AUCs), ie, 0.961 +/- 0.025, 0.946 +/- 0.021, and 0.912 +/- 0.032, respectively. In the population as a whole, optimal thresholds for stenosis were Qa less than 750 mL/min alone and in combination with dQa greater than 25% (efficiency, 90%); however, the best threshold depended on anastomotic site; it was Qa less than 750 mL/min for an AVF at the wrist and Qa less than 1,000 mL/min for an AVF in the midforearm. Qa was the best predictor of incipient thrombosis (AUC, 0.981 +/- 0.013) with an optimal threshold at less than 300 mL/min (efficiency, 94%). Pooled intra-assay and interassay variation coefficients were 8.2% for MAP, 7.9% for Qa, and 11.2% for Qa/MAP. CONCLUSION: Our study shows that ultrasound dilution Qa measurement is a reproducible and highly accurate tool for detecting stenosis and predicting thrombosis in forearm AVFs. Neither Qa/MAP nor dQa improve the diagnostic performance of Qa alone, although its combination with dQa increases the test's sensitivity for stenosis

A best-practice position statement on pregnancy after kidney transplantation: focusing on the unsolved questions. The Kidney and Pregnancy Study Group of the Italian Society of Nephrology

Kidney transplantation (KT) is often considered to be the method best able to restore fertility in a woman with chronic kidney disease (CKD). However, pregnancies in KT are not devoid of risks (in particular prematurity, small for gestational age babies, and the hypertensive disorders of pregnancy). An ideal profile of the potential KT mother includes “normal” or “good” kidney function (usually defined as glomerular filtration rate, GFR ≥ 60 ml/min), scant or no proteinuria (usually defined as below 500 mg/dl), normal or well controlled blood pressure (one drug only and no sign of end-organ damage), no recent acute rejection, good compliance and low-dose immunosuppression, without the use of potentially teratogen drugs (mycophenolic acid and m-Tor inhibitors) and an interval of at least 1–2 years after transplantation. In this setting, there is little if any risk of worsening of the kidney function. Less is known about how to manage “non-ideal” situations, such as a pregnancy a short time after KT, or one in the context of hypertension or a failing kidney. The aim of this position statement by the Kidney and Pregnancy Group of the Italian Society of Nephrology is to review the literature and discuss what is known about the clinical management of CKD after KT, with particular attention to women who start a pregnancy in non-ideal conditions. While the experience in such cases is limited, the risks of worsening the renal function are probably higher in cases with markedly reduced kidney function, and in the presence of proteinuria. Well-controlled hypertension alone seems less relevant for outcomes, even if its effect is probably multiplicative if combined with low GFR and proteinuria. As in other settings of kidney disease, superimposed preeclampsia (PE) is differently defined and this impairs calculating its real incidence. No specific difference between non-teratogen immunosuppressive drugs has been shown, but calcineurin inhibitors have been associated with foetal growth restriction and low birth weight. The clinical choices in cases at high risk for malformations or kidney function impairment (pregnancies under mycophenolic acid or with severe kidney-function impairment) require merging clinical and ethical approaches in which, beside the mother and child dyad, the grafted kidney is a crucial “third element”

A prospective controlled trial on effect of percutaneous transluminal angioplast on functioning arteriovenous fistulae survival

Balloon angioplasty (PTA) is an established treatment modality for stenosis in dysfunctional arteriovenous fistulae (AVF), although most studies showing efficacy have been retrospective, uncontrolled, and nonrandomized. In addition, it is unknown whether correction of stenosis not associated with significant hemodynamic, functional, and clinical abnormality may improve survival in AVF. This study was a prospective controlled open trial to evaluate whether prophylactic PTA of stenosis not associated with access dysfunction improves survival in native, virgin, radiocephalic forearm AVF. Sixty-two stenotic, functioning AVF, i.e., able to provide adequate dialysis, were enrolled in the study: 30 were allocated to control and 32 to PTA. End points of the study were either AVF thrombosis or surgical revision due to reduction in delivered dialysis dose. Kaplan-Meier analysis showed that PTA improved AVF functional failure-free survival rates (P = 0.012) with a fourfold increase in median survival and a 2.87-fold decrease in risk of failure. Cox proportional hazard model identified PTA as the only variable associated with outcome (P = 0.012). PTA induced an increase in access blood flow rate (Qa) by 323 (236 to 445) ml/min (P < 0.001), suggesting that improved AVF survival is the result of increased Qa. PTA was also associated with a significant decrease in access-related morbidity by approximately halving the risk of hospitalization, central venous catheterization, and thrombectomy (P < 0.05). This study shows that prophylactic PTA of stenosis in functioning forearm AVF improves access survival and decreases access-related morbidity, supporting the usefulness of preventive correction of stenosis before the development of access dysfunction. It also strongly supports surveillance program for early detection of stenosis

Presença de Aedes aegypti em Bromeliaceae e depósitos com plantas no Município do Rio de Janeiro, RJ

Relata-se a freqüência de vegetais Bromeliaceae e de outros criadouros com plantas positivos para Aedes aegypti durante dois ciclos operacionais (tratamento focal) consecutivos no Município do Rio de Janeiro, RJ, cujos períodos foram de 12 de novembro de 2000 a 9 de março de 2001 e 12 de março de 2001 a 15 de junho de 2001. O trabalho destaca as implicações epidemiológicas oriundas da crescente utilização dessas plantas para fins decorativos.The frequency of Bromeliaceae and other plant breeding places where Aedes aegypti can be found is reported during two consecutive operational cycles (focal treatment) in the city of Rio de Janeiro. These cycles took place from November 12 2000 to March 9 2001 and from March 12 2001 to June 15 2001. This study concentrates on the epidemiological implications resulting from the growing use of these plants as decorative living objects

Linkage analysis for the diagnosis of autosomal dominant polycystic kidney disease, and for the determination of genetic heterogeneity in Italian families

Sixty-eight individuals from six Italian families in which autosomal dominant polycystic kidney disease (ADPKD) is segregating, were typed in DNA polymorphisms linked to the PKD1 locus on chromosome 16. A total of ten probes were used: 3' HVR, HMJ1, EKMDA, GGG1, 26-6, VK5B, 218EP6, 24.1, CRI090, and 41.1. Zmax was 4.502 at theta = 0.082 between ADPKD and 3'HVR, and 4.382, 1.947, and 1.576 between ADPKD and GGG1, 26.6, and 218EP6, respectively, at theta = 0.0. No clear evidence of genetic heterogeneity was found. Multipoint analyses were consistent with linkage to PKD1. Twenty-nine diagnoses and 16 exclusions made by ultrasonography were confirmed by genotype determinations; in two clinically uncertain cases, DNA analysis predicted one individual as being affected and the other unaffected

Un caso di insufficienza renale acuta secondaria a malattia di MC-Ardle ad esordio tardivo. [A case of acute renal failure secondary to late-onset McArdle's disease].

INTRODUZIONE: La malattia di McArdle, o glicogenosi tipo V, è una malattia autosomica recessiva dovuta alla carenza della fosforilasi muscolare, un enzima che gioca un ruolo chiave nella demolizione del glicogeno durante un esercizio fisico, ed è caratterizzata da affaticamento, mialgia, crampi e debolezza muscolare con un importante aumento nei livelli ematici di creatinchinasi e rabdomiolisi con mioglobinuria, che può portare ad insufficienza renale acuta. La malattia di McArdle generalmente si manifesta tra i 15 ed i 30 anni; una comparsa tardiva è davvero inusuale. CASO CLINICO: riportiamo il caso di un paziente, maschio, di 68 anni, giunto in pronto soccorso per astenia, vertigini, diarrea ed oligoanuria. Il paziente è stato sottoposto a cinque sedute emodialitiche consecutive, con successiva ripresa della diuresi e ripristino della funzione renale. Il nostro paziente soffriva di astenia e dolore muscolare sin dalla giovane età: questi dati anamnestici, insieme ai persistenti livelli elevati di CPK ed in assenza di cause tossiche od infettive, ci hanno portato al sospetto di un disordine metabolico non comune, poi confermato dalla biopsia muscolare. CONCLUSIONI: sino ad oggi non esistono specifiche terapie per la glicogenosi tipo V. Una dieta ricca in proteine e saccarosio, la supplementazione di vitamina B6 e di creatina non hanno portato risultati brillanti. La terapia piu’ adatta sembra essere una moderazione dell’esercizio fisico, che migliora la tolleranza all’attività muscolare e l’afflusso di sangue ai muscoli, provvedendo all’aumento di glucosio ed acidi grassi alle fibre muscolari. INTRODUCTION: Mc Ardles disease, also known as Type V glycogen storage disease, is a rare deficiency of the enzyme glycogen phosphorylase in muscle cells, inherited as an autosomal recessive trait. In the absence of this enzyme, muscles cannot break down glycogen during exercise, so in patients affected by McArdles disease even moderate physical activity produces cramps, pain and fatigue. Anaerobic activity leads to severe fixed contractures and rhabdomyolisis with myoglobinuria and raised serum creatine-kinase, which, in turn, can lead to acute renal failure. Disease onset is usually in early childhood, although diagnosis is often not made until the second or third decade. CASE REPORT: We present the case of a 68-year-old man who presented to the Emergency Room with fatigue, vertigo, diarrhea and oliguria. The patient underwent five daily hemodialysis sessions, diuresis reappeared and there was progressive recovery of renal function. The patient described episodes of fatigue and muscular pain occurring since childhood: the positive personal history, together with persistently raised CPK levels in the absence of any infective or toxic cause of myositis, led us to suspect the presence of this rare metabolic disease, which was subsequently confirmed by muscle biopsy. CONCLUSION: To date, there is no specific treatment for type V glycogenosis, although a diet rich in protein and saccarose, vitamin B6 supplementation and creatine administration are generally recommended. Moderate physical activity can help manage symptoms by improving exercise tolerance and blood supply to the muscles, ensuring provision of glucose and free fatty acids for the muscle fibers

SURGICAL APPROACH TO RECURRENT STENOSIS IN NATIVE A-V FISTULA: NEOANASTOMOSIS OR GRAFT INTERPOSITION ?

Recurrent stenosis usually located in the perianastomotlc site, is the leading cause of native arterio-venous fistula (AVF) failure. Surgery is, considered the treatment of choice: usually a more proximal, neo-anastomosis is, created, but its drawback is the loss of vessel sites available for puncture

IL DUPLEX SCANNER E L'ANGIOGRAFIA DIGITALIZZATA NELLA PATOLOGIA DEGLI ASSI CAROTIDEI

The Authors emphasize the Duplex-Scanner validity in the diagnosis of sovraortic trunks disease. They compared 55 patients, examined first with Duplex-Scanner, and after with Digita] Su~btraction Angiography. They found a significant agreement (max 20% of stenosis percentage difference) in 87% of the examined patients. In Authors' opinion Duplex-Scanner - utilized by \ub7an expert operator - is the choice device for the screening of the sovraortic trunk diseases, and in the follow-up of the operate patient

Central role of vasopressin in sodium/water retention in hypo-and hypervolemic nephrotic patients: a unifying hypotesis

The underfill and overflow hypotheses are usually held as mutually exclusive mechanisms for explaining sodium/water retention in nephrotic syndrome, but neither of them is entirely convincing. In this paper, we will briefly summarize the experimental and clinical evidence in favor of and against each hypothesis. Based on our personal observations, we propose a unifying hypothesis in which underfill and overflow are subsequent stages of the disease. In the transition, a central role is played by vasopressin, which is secreted in the two phases, respectively, by a volume and an osmotic stimulus; therefore, persistent sodium/water retention is maintained through the vascular and tubular effects of this peptide. In addition, we propose that vasodilation and sodium/water excretion could ensue when both stimuli for vasopressin release fade away, leading to the resolution of the syndrome