Hemodiafiltration with endogenous reinfusion with and without acetate-free dialysis solutions: effect on ESA requirement.

BACKGROUND: Hemofiltrate reinfusion (HFR) is a form of hemodiafiltration (HDF) in which replacement fluid is constituted by ultrafiltrate from the patient 'regenerated' through a cartridge containing hydrophobic styrene resin. Bicarbonate-based dialysis solutions (DS) used in routine hemodialysis and HDF contain small quantities of acetate (3-5 mM) as a stabilizing agent, one of the major causes of intradialytic hypotension. Acetate-free (AF) DS have recently been made available, substituting acetate with hydrochloric acid. The impact of AF DS during HFR on Hb levels and erythropoietic-stimulating agent (ESA) requirement in chronic dialysis patients was assessed. PATIENTS AND METHODS: After obtaining informed consent, 30 uremic patients treated by standard bicarbonate dialysis (BHD, DS with acetate) were randomized to treatment in 3-month cycles: first AF HFR, followed by HFR with acetate, and again AF HFR. At the beginning and end of each period, Hb and ESA requirements were evaluated. RESULTS: A significant increase in the Hb level was observed throughout all periods of HFR versus BHD (from 11.1 to 11.86 g/dl; p = 0.04), with a significant decrease of ESA requirements from 29,500 to 25,033 IU/month (p = 0.04). CONCLUSION: Regardless of the presence or absence of acetate in DS, HFR per se allows a significant lowering of ESA dosage versus BHD, while at the same time increasing Hb levels. Taking for granted the clinical impact produced, HFR seems to provide a relevant decrease in end-stage renal disease patient costs.

[Report of the National Renal Ultrasound Study Group on the ultrasound activity of nephrology care units in Italy]. / Report del gruppo di studio nazionale di ecografia renale sull'attivita' ecografica delle U.O. di Nefrologia in Italia.

The presence of operational and organizational differences in the use of ultrasonography in Italian nephrology units has prompted this survey on a nationwide scale. The survey was carried out by questionnaire and included questions about the activity and equipment of each nephrology unit, dedicated personnel and relevant training, and the fields of ultrasonography application. Seventy-five percent of the contacted care units replied to the questionnaire. Twenty-six percent of these performed their ultrasound examinations outside the care unit, sharing equipment with other units. The mean lifetime of ultrasound devices was longer (5.8 years) than allowed by the electro-medical equipment regulations. In spite of an increasing number of nephrologists with ultrasonographic expertise, in each care unit the percentage of physicians performing ultrasound examinations was very low. The number of operators who learned this methodology directly at surgeries using ultrasound devices was higher than that of operators who attended training courses and obtained the relevant certificates. In addition to the kidneys and urinary tract, other body districts investigated included abdominal organs, parathyroids, vascular access for hemodialysis treatment, and the bone-joint system. Moreover, ultrasonography was widely used for surgical procedures in nephrology. However, in spite of the widespread application of ultrasound imaging, the use of radiology was unexpectedly high (80%). Finally, the questionnaire results evidenced the particular care of nephrologists towards follow-up for situations of nephrological interest, such as acquired renal cysts, vascular access visualization, and monitoring of parathyroids.

Predictive role of duplex Doppler ultrasonography in the diagnosis of acute renal obstruction in patients with unilateral renal colic.

OBJECTIVE: The aim of our study was to assess the role of Doppler ultrasonography (DU) by resistive index (RI) and the difference of the RI (DeltaRI) in patients with acute unilateral renal obstruction. PATIENTS AND METHODS: We studied 36 consecutive patients (12 female, 24 male; mean age 45.6 +/- 8.4 years) with suspected renal colic by intravenous pyelography (IVP) and DU with determination of the RI and the Delta RI. A RI of >= 0.70 and a DeltaRI of >= 0.06 were considered suggestive of obstruction. IVP was considered as the "gold standard". RESULTS: In the studied population, RI was 0.664 +/- 0.060 in the affected kidney site of symptoms and 0.614 +/- 0.025 in the contralateral one, with an overall Delta RI of 0.049 +/- 0.062. At IVP, 14 patients resulted within normal range (Group A; 39%), 6 patients showed lithiasis without obstruction (Group B; 17%), 8 patients showed delayed excretion of the contrast medium (Group C; 22%), and 8 patients showed a functional exclusion of the kidney (Group D; 22%). One-way analysis of variance showed the IVP group significantly related to Delta RI with the highest values in Groups C (DeltaRI of 0.093 +/- 0.051; p<0.001) and D (DeltaRI of 0.116 +/-0.030; p<0.001) in comparison with Group A (DeltaRI of 0.001 +/-0.038) and Group B (DeltaRI of 0.015 +/-0.024). No differences were detected between Groups C and D (p=0.223) and between Groups A and B (p-0.472). DeltaRI measurement with DU permitted to predict the renal obstruction with a sensitivity of 93.8%, a specificity of 95.0% and an accuracy of 94.4%. CONCLUSIONS: Intrarenal Doppler ultrasonography represents a sensitive and highly specific test that can significantly contribute to the diagnosis of obstruction in patients with acute renal colic. It should be used as the first line imaging method in suspected acute renal colic, as well as for patients with renal insufficiency, pregnant women or for patients with adverse reactions to contrast media

Doppler ultrasound and renal artery stenosis: An overview.

Renovascular disease is a complex disorder, most commonly caused by fibromuscular dysplasia and atherosclerotic diseases. It can be found in one of three forms: asymptomatic renal artery stenosis (RAS), renovascular hypertension, and ischemic nephropathy. Particularly, the atherosclerotic form is a progressive disease that may lead to gradual and silent loss of renal function. Thus, early diagnosis of RAS is an important clinical objective since interventional therapy may improve or cure hypertension and preserve renal function. Screening for RAS is indicated in suspected renovascular hypertension or ischemic nephropathy, in order to identify patients in whom an endoluminal or surgical revascularization is advisable. Screening tests for RAS have improved considerably over the last decade. While captopril renography was widely used in the past, Doppler ultrasound (US) of the renal arteries (RAs), angio-CT, or magnetic resonance angiography (MRA) have replaced other modalities and they are now considered the screening tests of choice. An arteriogram is rarely needed for diagnostic purposes only. Color-Doppler US (CDUS) is a noninvasive, repeatable, relatively inexpensive diagnostic procedure which can accurately screen for renovascular diseases if performed by an expert. Moreover, the evaluation of the resistive index (RI) at Doppler US may be very useful in RAS affected patients for predicting the response to revascularization. However, when a discrepancy exists between clinical data and the results of Doppler US, additional tests are mandatory.

Effect of on-line hemodiafiltration with endogenous reinfusion (HFR) on the calcium-phosphorus metabolism: medium-term effects.

AIM: The purpose of the study was to examine the effect of hemodiafiltration with endogenous reinfusion (HFR) compared to hemodialysis (HD) on 28 uremic patients with secondary hyperparathyroidism (2HPT) but positively selected for good and stable control of phosphatemia in order to evaluate the independent effects of dialysis treatments on bone turnover metabolism. METHODS: The study was divided into 3 periods of observation: a) HD for three months; b) HFR for three months; c) HFR for a further 3 months. We analysed the trend of: whole PTH, 1-84 PTH, 7-84 PTH, alkaline phosphatase and its bone isoenzyme, total and ionised calcium, phosphatemia, dose of phosphate binder agents, beta2-microglobulin, CRP. All the variations found were evaluated through mean values +/- SD, t-tests, multivariate analysis. RESULTS: We observed a deceleration in bone turnover characterized by a reduction of the total and bone alkaline phosphatase (IU/mL) from 92.3 +/- 82.8 and 35.8 +/- 49.8 at the end of HD to 63.4 +/- 23.9 and 16.0 +/- 8.7 at the end of HFR, respectively, and 1-84 PTH from 317.5 +/- 264.6 pg/mL at the end of HD to 287.5 +/- 258.9 pg/mL at the end of the 3rd month of HFR. Beta2-microglobulin was reduced from 32.9 +/- 16.1 mg/L at the end of HD to 26.4 +/- 8.1 mg/L already at the end of the first three months of HFR. CRP was reduced from 2.5 +/- 2.6 mg/dL at the beginning of the study to 1.3 +/- 1.7 mg/dL at the end of HFR. There were no differences with regard to: dialytic efficiency, nutritional status, calcemia, phosphatemia (maintained in the K-DOQI range for the entire duration of the study), also thanks to more careful use of phosphate chelating agents. CONCLUSION: We are of the opinion that HFR - essentially thanks to the use of ultrapure endogenous infusate - induces a deceleration in bone turnover due to 2PHT. In addition, phosphate subtraction in HFR is better compared to HD, thanks to the improvement of the anti-inflammatory conditions by removing the cytokines harmful to bone metabolism and excluding a priori the negative effects related to hyperphosphatemia.

[A closed cycle]. / Un ciclo chiuso.

A young girl was admitted to the Renal Unit of our Hospital because of loin pain and mild renal failure with bilateral hydronephrosis. The abdomen ultrasound was very helpful to get the right diagnosis.

Azygos arch cannulation by central venous catheters for hemodialysis.

Cannulation of central veins and placement of catheters for temporary haemodialysis is a common procedure in the management of patients with end stage renal failure. The internal jugular vein is the site of choice for central venous catheter placement, being associated with the lowest complication rate. This procedure can be associated with a variety of malpositions of the catheter and rarely, can lead to significant morbidity and even mortality, if this is not recognised and corrected early. For anatomical reasons, the risk of azygos arch cannulation is substantially increased if catheters are inserted via left-sided veins. We report a case with a rare complication associated with the insertion of a catheter for temporary haemodialysis.

[Twinkling artifact in kidney stone disease]. / Arlecchino e la calcolosi urinaria.

BACKGROUND: Ultrasonography artifacts are false representations of the image caused by the interaction between the ultrasound and the tissues. The ability to identify artifacts is an important source of information that can help the clinician in performing a correct diagnosis. The twinkling artifact (called 'Effetto Arlecchino' by the Italians) consists of a series of colored pixels that appear inside, around and often along the shadow cone of the calculi. METHODS: We evaluated the clinical effectiveness of this artifact in the diagnosis of kidney stone disease. In 107 ultrasonography cases of hyperechogenic formations with clinical features of kidney stones, we used the color box to evoke the twinkling artifact. Of the 107 cases, 102 cases (95%) presented this artifact, while five cases did not. Moreover, this artifact was present in all urethral and bladder stones and in 62/67 kidney stone cases. CONCLUSIONS: In our experience, we found that the twinkling artifact is often positive in urinary stone disease, and the ability to identify it adds useful information to the diagnosis of urinary kidney stone disease.

The management of hemodialysis arteriovenous fistulas in well functioning renal transplanted patients: many doubts, few certainties.

UNLABELLED: Vascular access (VA) for hemodialysis (HD) is one of the most important clinical problems in end-stage renal disease (ESRD) patients because it can limit a life support system and can influence long-term dialysis patient survival. Nevertheless, VA becomes useless after a successful renal transplant. Therefore, we wanted to evaluate the natural history of arteriovenous fistulas (AVF) in renal transplanted patients and the possibility of maintaining the fistula as patent or not. METHODS: A retrospective study was conducted to evaluate kidney transplant patients in our unit from April 1994 to April 2004. We studied 542 patients. RESULTS: There were 365 patients with a well functioning kidney. Eighty-six patients died. Ninety-one patients were put back on dialysis: 89 patients on HD and two patients on CAPD. Of the 365 patients with functioning kidney transplants, 198 patients demonstrated a patent fistula, while 167 patients had a closed fistula. One hundred and twenty-five patients had a spontaneous closure and 42 patients had a surgical closure. Of the 89 patients put back on dialysis, 49 patients used the previous AVF, while it was necessary to create a new VA in 40 patients. CONCLUSIONS: As demonstrated by the results of our study, after renal transplantation the possibility of spontaneous AVF closure caused by a thrombosis is not a rare event. The dilemma is whether to preserve a fistula that could be useful in case of restarting HD or to perform a systematic fistula closure because of cardiac output and cardiac failure risks. Concerning this question there is no consensus between different authors in the literature. In reviewing the literature and analyzing our data, we conclude that the definite indications for AVF closure in well functioning renal transplanted patients are heart failure, high flow fistula, VA complications and important aesthetic reasons. Routine AVF closure is not indicated until prospective and randomized studies can demonstrate the ability of this procedure to reduce the high incidence of cardiac morbidity and mortality that is present, even after renal transplantation.