Rafael Ponikvar

To assess the possibility of using filtered plasma instead of postfilter ionized calcium (iCa) for the assessment of anticoagulation in plasma exchange (PE) with citrate anticoagulation.

In 1996 we performed tandem membrane plasma exchange-hemodialysis in a 3-year-old girl and tandem immunoadsorption-hemodialysis with citrate as the only anticoagulant in a patient with Goodpasture's syndrome. In the present study, we evaluated the feasibility, efficacy and safety of 24 tandem plasma exchange/immunoadsorption hemodialysis procedures in four different circuit setups with citrate as the only anticoagulant. In two setups, the tandem procedures were connected in series (plasma exchange hemodialysis and immunoadsorption hemodialysis), while in the other two setups they were in parallel (plasma exchange hemodialysis with independent blood circuits and plasma exchange hemodialysis with independent arterial blood lines, but with a common return line). All tandem procedures were feasible, efficient and safe. No serious side-effects were recorded. The most elegant setup was the procedure with independent, parallel blood circuits. However, serial tandem procedures provided for the elimination of citrate and normalization of electrolytes before blood was returned to the patient.

In plasma exchange (PE), contrary to dialysis, there is no ultrafiltration, and the volume of anticoagulant contributes to volume overload of the patient and might also reduce PE efficiency through dilution. To reduce the volume of citrate, we compared 4 and 15% citrate anticoagulation protocols in PE in a randomized study, aiming to evaluate PE efficacy, anticoagulation efficiency, and overall safety. In addition to standard biochemical analyses during PE treatments, the elimination rate (ER) of immunoglobulins was calculated to evaluate PE efficacy. Anticoagulation was evaluated by postfilter ionized calcium, visual evaluation of the extracorporeal system, and change in the sieving coefficient (SC) during PE. Accumulation of citrate was determined by calculating the total‐to‐ionized calcium ratio and measuring the citrate concentration after PE. One hundred forty procedures (70 in each group) were performed in 37 patients. The mean citrate infusion rate was 197 ± 10 mL/h in the 4% and 59 ± 5.5 mL/h in the 15% groups, respectively; the total volume of infused citrate was 502 ± 77 mL versus 164 ± 52 mL (P < 0.001). ER for immunoglobulin G (0.57 ± 0.06 vs. 0.55 ± 0.1, P = 0.18), M, and A were comparable. Ionized calcium was stable during the procedures, and there were no significant side effects. Although postfilter ionized calcium was on the upper limit of the target range (0.41 ± 0.16 vs. 0.37 ± 0.14 mmol/L, P = 0.38), the visual assessment score was excellent, and even a rise in SC was observed during the procedures in both groups. The total‐to‐ionized calcium ratio was increased in 20 versus 22% of procedures, and citrate concentrations after PE were also similar (1306 ± 441 vs. 1263 ± 405 μmol/L). To conclude, we were unable to show superior PE efficacy in the 15% citrate group, but we significantly reduced the infused volume, which is important in patients with fluid overload. Both citrate protocols were found to provide excellent anticoagulation without significant metabolic disturbances or other side effects, confirming the safety of 15% citrate as anticoagulant during PE.

The aim of our retrospective analysis with prospective collected data was to evaluate the patency of thigh expanded polytetrafluoroethylene (ePTFE) arteriovenous (AV) grafts, which were placed in chronic hemodialysis patients by the same interventional nephrologist skilled in hemodialysis access vascular surgery. From February 1991 until March 2013, 35 thigh ePTFE grafts were placed in 31 chronic hemodialysis patients. Twenty (57%) were women, mean age 58.7 ± 14.5, dialysis vintage 11.9 ± 7.3 years, mean number of previous vascular accesses 4.4 ± 1.9. Two of the 35 (5.7%) grafts were lost to follow‐up, immediate failure occurred in 1/35 (2.8%) grafts, and thrombosis appeared within 30 days in 2/35 (5.7%) grafts. Four of the 31 patients died with functioning grafts, while in 9/31 patients the grafts are still patent. In the remaining 17 AV grafts that thrombosed, no surgical intervention was performed in 8/17, while 18 thrombectomies (two per graft) were performed in 9/17 to maintain graft patency. The immediate success rate was 97.1%. Primary patency was from 0–3251 days, on average 906 ± 898, median 472, cumulative patency (N = 33) was from 0–3251 days, on average 1174 ± 954, median 966. Cumulative patency of the grafts that were patent for more than 30 days (N = 30) was from 153–3251 days, on average 1298 ± 921, median 1207. The ePTFE graft survival after the 1st year was 78%, after the 2nd year 74%, after the 3rd year 66%, after the 4th year 56%, after the 5th year 52%, and after the 9th year 13 %. The longest patency was 3251 days without any intervention. Steal syndrome occurred in two patients after 2522 and 275 days after fistula placement.

Introduction and Aims: Although several studies have demonstrated survival and economic advantages of peritoneal dialysis (PD) over haemodialysis (HD), there are few reports comparing the costs of HD and PD access care in the literature. The aim of our study was to compare the resources required to establish and maintain the dialysis access in patients who initiated HD with a tunneled cuffed catheter (TCC) or an arteriovenous fistula (AVF) with those initiating PD.

Two single-lumen, noncuffed catheters in the same jugular vein have been used as preferred vascular access in our hemodialysis (HD) and apheresis patients in past years. The aim of this retrospective study was to analyze the clinical outcome of such a vascular access and the reasons for catheter removal. In 129 adult patients, aged 69 ± 13 years, 56% males, treated by HD (121 patients) or apheresis (8 patients), two single lumen, pre-curved 8 Fr catheters (Medcomp, Harleysville, PA, USA) inserted into the same jugular vein were used as vascular access between January 2009 and April 2010. The catheters were inserted into the left jugular vein in 21 patients, and into the right jugular vein in 108 patients. A 30% solution of trisodium-citrate was used as a locking solution, and 2% mupirocin ointment was routinely applied to the exit site. The catheters were removed in 86 patients after 1-288 days, median 17.5 days. In 74 patients, there was either no need for further dialysis or an arteriovenous fistula was constructed (17 patients). In 10 patients, wire exchange was performed for correction of a displaced functional catheter (after 6-201 days), and in only two patients the catheters were removed due to infection on days 10 and 184. The longest period of a catheter functioning without intervention was 387 days. Fifteen patients died with functional catheters left in place (duration 1-387 days). In four patients, the catheters were still functional at the time of analysis (duration 198-268 days). Another nine patients were transferred to other dialysis centers (after they had been followed up at our center lasting for 1-63 days), with no data on their outcome after transfer. Fifteen patients were lost to follow up after insertion. Two single-lumen, noncuffed catheters in the same jugular vein, locked with 30% citrate, seem to be a safe and long lasting method of vascular access for hemodialysis and apheresis in some patients, but further prospective studies are needed to evaluate the clinical outcome of this type of vascular access.

The aim of our retrospective study was to present the success of surgical thrombectomy in acutely thrombosed, arteriovenous (AV), expanded polytetrafluoroethylene (ePTFE) grafts. Patients from hemodialysis centers in Slovenia were admitted to our dialysis center after acute thrombosis of their AV graft to undergo surgical thrombectomy under local anesthesia as an outpatient procedure. In 55 chronic hemodialysis patients, of whom 26 were men (47.3%), with a mean age of 63 ± 13 years (range 35-84 years), and diabetes mellitus in 11 patients (20%), 59 ePTFE AV grafts thrombosed. A total of 129 thrombectomies were performed, on average 2.2 ± 2.1 per graft (range 1-13). Primary patency (defined as the time from AV graft creation to first thrombosis) was 638 ± 633 days (range 10-2586, median 418 days), secondary patency (defined as the time from first thrombectomy to abandonment) was 451 ± 472 days (range 0-1994, median 305 days), and cumulative patency (defined as the time from creation to abandonment) was 1089 ± 685 days (range 25-3020, median 1031 days). In 46 (78%) of the AV grafts, the first thrombectomy was successful. The secondary patency rates after 1, 2, 3, 4, and 5 years were 76%, 66%, 54%, 14%, and 14%, respectively (13/59 unsuccessfully thrombectomized grafts were excluded). Cumulative patency after 1, 2, 3, 4, and 5 years was 88.1%, 67.8%, 44.7%, 27.1%, and 16.9%, respectively. In conclusion, surgical thrombectomy after thrombosis of an AV graft in the arm or thigh, performed by interventional nephrologists and followed, if required, by angioplasty, significantly prolonged the patency of the majority of thrombosed AV grafts.