Stelios Panagoutsos

Peritoneal Catheters and Related Infections

Catheter related infectious complications (exit-site infections, tunnel infections, and peritonitis) remain the major reasons for technique failure during the three decades since, continuous ambulatory peritoneal dialysis (CAPD) treatment has been first established. Despite improvements in catheter’s survival rates, catheter related complications result in an increase in the cumulative patients’ morbidity and often leading to the catheter removal. The ideal catheter provides reliable and rapid dialysate flow rates without leaks or infections. Among several types, the double-cuff straight Tenckhoff catheter, developed in 1968, is still the most widely used, although its use is decreasing in favour of swanneck catheters. Although there are onlu few well-designed trials comparing catheters and catheters related infectious complications, controlling for all other important variables, no difference in these complications among the main types of catheters was seen. The single cuff catheters have been associated with a shorter survival rate and time to the first peritonitis episode than the double-cuff catheters. Also exit-site infections were found to be more frequent and significantly more resistant to treatment with single-cuff compared to double-cuff ones. Finally, better results have been reported with the latest developed presternal peritoneal dialysis catheter both regarding survival rates and exit-site infection and peritonitis rates. Recently a renewed interest in continuous flow peritoneal dialysis stimulated inventions of imaginative, double-lumen catheters since a suitable peritoneal access is a sine qua non condition for the development of this new technique of peritoneal dialysis.

Vascular access for hemodialysis: postoperative evaluation and function monitoring

SummaryVascular access (VA) survival is a crucial issue associated with morbidity and mortality of patients undergoing maintenance hemodialysis. The development of stenosis is the major factor that leads to VA failure. Strategies for early detection of lesions within a VA system before serious complications arise are therefore crucial. The implementation of a VA surveillance program could lead to timely detection of VA dysfunction and referral for correction, reduction in central venous catheter use and decrease in hospitalization and VA-related cost. Suggested methods for arteriovenous fistulae and grafts surveillance include blood flow measurement, static pressure evaluation and duplex ultrasonography. Physical examination is an accepted method in contrast to nonstandardized dynamic pressure measurement for grafts. Access recirculation (not urea based) and dynamic pressure measurements are accepted methods for fistulae. Decreasing URR or Kt/V (otherwise unexplained) and increased (negative) arterial pressure in the dialysis machine are methods of limited sensitivity and specificity for both fistulae and grafts. Measurement of access blood flow has been proposed as the gold standard for the screening of all types of VA. Access flow can be measured by various techniques which are direct or indirect. Several studies about VA surveillance programs have demonstrated conflicting results. Larger, randomized controlled trials need to be carried out in order to clarify whether surveillance programs are necessary and which is the best surveillance strategy for each type of VA.

Can dialysis modality influence quality of life in chronic hemodialysis patients? Low-flux hemodialysis versus high-flux hemodiafiltration: a cross-over study.

Background: Hemodiafiltration with online preparation of the substitution [online high-flux hemodiafiltration (OHDF)] and hemodiafiltration with prepared bags of substitution (HDF) are important, recently widely used renal replacement therapies in patients with end-stage renal disease. However, there is little information on the comparative impacts of these modalities versus conventional low-flux hemodialysis (HD) on the quality of life (QoL) of HD patients. This study investigates the effect of dialysis modality on QoL in chronic HD patients. Methods: In this prospective, randomized, cross-over, open label study, 24 patients were enrolled. Their age were 62 ± 13.34 years (mean ± SD), with the duration of dialysis of 31 ± 23.28 months (mean ± SD). Five of the patients were women. QoL was measured by the Short-Form Health Survey with 36 questions (SF-36) and subscale scores were calculated. Each patient received HD, OHDF, and HDF for 3 months, with the dialysis modality subsequently being altered. They completed the questionnaire of QoL at the end of each period. Results: There were statistical significant differences in QoL for the total SF-36 [36.1 (26.7–45.7) and 40.7 (30.2–62.8)], for classic low-flux HD and high-flux hemodiafiltration, for bodily pain [45 (26.9–66.9) and 55 (35.6–87.5)], and for role limitations due to emotional functioning [0 (0–33.3) and 33.3 (0–100)], respectively. The scores did not differ significantly between the two types of hemodiafiltration. Conclusions: Our study indicates that QoL differs significantly among patients receiving low-flux HD and high-flux hemodiafiltration, on total SF-36, bodily pain, and role limitations due to emotional functioning. Convective modalities may offer better QoL than diffusive HD.

LIPOPROTEIN ABNORMALITIES IN HEMODIALYSIS AND CONTINUOUS AMBULATORY PERITONEAL DIALYSIS PATIENTS

Lipid abnormalities are important variables in the development of vascular atherosclerotic lesions in ESRD patients while Lp(a) represents an independent risk factor. In order to evaluate lipid changes in HD and CAPD patients, serum cholesterol (TC), HDLc, LDLc, TG, apo-lipoproteins (AI,AII,B,E), Lp(a), and albumin levels were estimated in 109 ESRD dialyzed patients, 46 in HD and 63 in CAPD (mean duration 50 ± 40 and 25 ± 19 months, respectively), and 45 volunteers with high serum levels of C and TG, without renal insufficiency. Both HD and PD group revealed statistically significantly higher levels than controls for TC, TG, LDL-C, Apo-B,-E, while HDL-C levels were significantly lower. Except for the lower serum albumin levels in both dialyzed groups after six months lower ApoAI levels and higher ApoB levels were observed in HD and PD patients respectively. Lp(a) levels remained unchanged in HD group, while a statistically significant increase appeared in PD patients that was negative correlated with the decreased serum albumin levels. These results indicate that renal replacement modalities result in a different effect in lipoprotein metabolism that may play an important role in atherosclerotic vascular disease of dialyzed ESRD patients.

Metformin-related lactic acidosis in patients with acute kidney injury

BackroundMetformin is nowadays considered as first-line therapy in individuals with non-insulin dependent diabetes mellitus (NIDDM). Metformin-related lactic acidosis (MALA) occurs more frequently after inappropriate use especially in patients with acute kidney injury (AKI) or chronic kidney disease (CKD). Thus, its prescription in these patients is contraindicated, while the role of dialysis is under evaluation.MethodsWe describe two cases of severe metformin-related lactic acidosis with underlying acute kidney injury, which were treated with dialysis.ResultsIn both cases, lactic acidosis occurred on a background of acute decline in renal function, possibly due to drug accumulation. It is interesting that metformin was contraindicated in one case.ConclusionLactic acidosis is a rare but potentially fatal adverse effect of metformin, particularly in patients with AKI, which should always be considered in clinical practice. Dialysis seems to contribute significantly to the management of this life-threatening condition and the improvement in outcome.

A hybrid approach to salvage a failing long-standing autogenous aneurysmal fistula in a hemodialysis patient

Very few studies have addressed the repair of autogenous and prosthetic-related false arteriovenous access (AVA) aneurysms in hemodialysis patients. Surgical management of complicated AVA-related aneurysms remains the gold standard method although covered stents have recently been introduced for the exclusion of such aneurysms, offering a minimally invasive therapy. In this paper, we describe a combination of open and endovascular repair for treating an anastomotic and a puncture-site aneurysm to salvage a failing long-standing autogenous radial-cephalic fistula in the wrist. Resection of the anastomotic aneurysm and reconstruction of the anastomosis proximally was initially performed. Via the first cm of the anastomosis, a Fluency® stent graft (SG) was inserted and it successfully excluded the mid-outflow vein false aneurysm. Such hybrid therapies may be the future of AVA revisions and this trend should not be overlooked by nephrologists and vascular surgeons.