Vladimir Premru

Treatment of hyperlipidemic acute pancreatitis with plasma exchange: a single-center experience.

Of the cases of acute pancreatitis, 1–7% are caused by severe hypertriglyceridemia and can be treated with plasma exchange (PE). We report on a large series of patients with acute hyperlipidemic pancreatitis (HLP) treated with PE. In the 1992–2008 period, 50 patients (45 ± 8 years old, 92% male) with acute HLP were treated with PE, during which 1–2 plasma volumes were exchanged. Heparin was used as anticoagulant in 85% of the procedures, and citrate in the rest. Cholesterol and triglycerides were measured before and after PE. In the 2003–2008 cohort of 40 patients, we retrospectively recorded an Acute Physiology and Chronic Health Evaluation II (APACHE II) score at the first PE session, hospital mortality, and length of hospital stay. A total of 79 PE treatments were done, 1–5 per patient. The volume exchanged was 4890 ± 1300 mL over a duration of 3.5 ± 2 h. During the first PE, the triglycerides were lowered from 58.9 ± 40.8 to 10.8 ± 10.8 mmol/L, and the total cholesterol was lowered from 20.0 ± 7.6 to 5.7 ± 4.3 mmol/L. In 10% of the procedures the plasmafilter was replaced, and in 3% the filter was clotted. Hypotension occurred in 3% of PE and there was one case of gastrointestinal bleeding after PE with heparin anticoagulation. In the 2003–2008 cohort, the median APACHE II score was 5 (range 0–15), the median overall hospital stay was 18 days (range 3–142 days) and the hospital mortality was 15%. To conclude, in acute hyperlipidemic pancreatitis, one to two plasma exchanges effectively reduce the serum triglyceride level. There is a low rate of procedure‐related complications. A mortality rate of 15% is considerable.

High cut-off membrane hemodiafiltration in myoglobinuric acute renal failure: a case series.

Acute renal failure is a major complication of rhabdomyolysis. New membranes for hemodialysis have been developed with a high cut‐off pore size allowing efficient removal of myoglobin. We report on six patients treated by hemodiafiltration with a high cut‐off membrane (HCO‐HDF) for myoglobinuric acute renal failure. Rhabdomyolysis was caused by infection in two patients, by a statin in one patient and a non‐traumatic crush in another, and followed cardiovascular surgery in two others. Ten HCO‐HDF procedures were performed. A high cut‐off hemofilter was used, with citrate anticoagulation and postdilutional fluid substitution of 2–3 L/h, dialysate flow 500 mL/min, and blood flow within 250–300 mL/min. Albumin losses were replaced by infusion of human albumin solution, and the mean myoglobin reduction ratio was 77% (range, 62–89%). An excellent clearance of 81 mL/min (range 42–131 mL/min) was achieved. Nearly 5 g of myoglobin was removed into the dialysate collected in one of the procedures. A high rebound in serum myoglobin, on average to 244% of the post‐procedure myoglobin level, was observed. The four patients alive at the time remained anuric for a week. Slow myoglobin elimination with a mean half‐time of 39 h (range 19–59 h) was observed in that period. Highly efficient myoglobin removal by high cut‐off membrane hemodiafiltration was demonstrated in our patients. Rapid redistribution from the extracellular fluid and sustained myoglobin release were suggested by the high rebound observed. Elimination of myoglobin within the body was shown in our study to occur slowly during the period of anuria.

Use of Myoglobin as a Marker and Predictor in Myoglobinuric Acute Kidney Injury

Serum creatine kinase (CK) is routinely used as a marker in the assessment of rhabdomyolysis and acute myoglobinuric kidney injury (Mb‐AKI), while the use of myoglobin is much less explored in this respect. We retrospectively analyzed the incidence of Mb‐AKI (creatinine [Cr] > 200 μmol/L) and the need for hemodialysis (HD) in 484 patients (70.5% males) with suspected rhabdomyolysis, grouped according to peak serum myoglobin (A: 1–5 mg/L, B: 5–15 mg/L, C: >15 mg/L). The median peak myoglobin was 7163 μg/L. Both peak Cr and peak CK were significantly higher in group C. The incidence of Mb‐AKI was 24.6% in group A, 38.6% in group B (P < 0.01 vs. group A), and significantly higher (64.9%) in group C (P < 0.001 vs. groups A and B). Fifty‐one patients (10.5%) needed HD, the proportion increasing from 6.7% in group A, and 12.3% in group B (NS), to 28.1% in group C (P < 0.001 vs. group A, P 0.01 vs. group B), and reaching 36.8% with myoglobin >20 mg/L. Creatine kinase correlated with the severity of rhabdomyolysis, but less so with Mb‐AKI. The peak Cr levels were not significantly different between patients divided by CK 60 μkat/L, or grouped into CK tertiles or quartiles. A significant proportion of patients with rhabdomyolysis experienced Mb‐AKI, whose frequency increased in parallel with myoglobin levels. Myoglobin levels above 15 mg/L were most significantly related to the development of AKI and the need for HD. Blood myoglobin could serve as a valuable early predictor and marker of rhabdomyolysis and Mb‐AKI.

Vascular access in children on chronic hemodialysis: a Slovenian experience.

The aim of our study was to report our experience with arteriovenous fistulas (AVFs) and non‐cuffed central venous catheters (CVCs) in children and adolescents with end‐stage renal disease (ESRD) on hemodialysis (HD). The children with ESRD (18 years or younger) who were hemodialyzed at the Center of Dialysis and Transplantation, Childrens Hospital, Ljubljana, in the period between December 1998 and December 2010 were included in our retrospective study. We recorded the data considering the CVCs and AVFs used for HD. Thirty‐one children (13 females, 18 males) with ESRD received HD treatment. The mean patient age when HD was started was 13.3 ± 3.4 years. Altogether, 35 AVFs were created, and the primary failure rate was 25.7% (9/35). The time to maturation was 4.0 ± 2.5 months. The mean patency of the AVF was 42.5 ± 51.9 months. Seventy‐seven CVCs (non‐cuffed) were inserted in the observation period; 89.6% of the CVCs were inserted in the jugular vein, and citrate locking was used in the interdialysis period. The CVCs were removed after 0.1–17.4 months (3.6 ± 3.7 months). The incidence of bacteremia was 0.9 episodes per 1000 catheter days. The preferred vascular accesses for pediatric hemodialysis are native AVFs; however, a single lumen, non‐cuffed, citrate‐locked CVC placed in a jugular vein can be acceptable as a long‐term vascular access when AVF cannot be constructed or used.

Hemodialysis Catheters With Citrate Locking in Critically Ill Patients With Acute Kidney Injury Treated With Intermittent Online Hemofiltration or Hemodialysis

The purpose of the study was to compare the long‐term catheter‐related complications associated with temporary untunneled hemodialysis catheters, locked with citrate in the interdialysis period, inserted in critically ill patients with acute kidney injury, between different catheter insertion sites (femoral vs. jugular and subclavian) and catheter types (single‐lumen [SL] vs. double‐lumen [DL]). In a retrospective clinical study, the long‐term catheter‐related complications in 290 critically ill patients treated with intermittent high‐volume online hemofiltration or hemodialysis between December 2004 and January 2008 were analyzed. Among 534 inserted catheters, 493 (92.3%) were femoral, 29 (5.4%) jugular, and 12 (2.3%) subclavian; 304 (56.9%) were SL and 230 (43.1%) were DL. There were 125 (20.3/1000 catheter days [c.d.]) thrombotic complications, while infectious complications were exceptionally rare, that is, only 13 (2.1/1000 c.d.), of which 10 (1.6/1000 c.d.) were possible catheter‐related bloodstream infections and 3 (0.5/1000 c.d.) exit‐site infections. The incidence rate of all thrombotic complications was significantly lower in all jugular and subclavian vs. all femoral catheters (7.7/1000 c.d. vs. 21.8/1000 c.d., P = 0.01), and in all SL vs. DL catheters (11.4/1000 c.d. vs. 32.2/1000 c.d., P < 0.001). The incidence rate of any possible catheter‐related bloodstream and exit‐site infections was not significantly different in all jugular and subclavian vs. all femoral catheters, neither in femoral SL vs. DL catheters. The major long‐term catheter‐related complications were thrombotic, and significantly more frequent in DL vs. SL catheters. Infectious complications were exceptionally rare, most probably due to the strict catheter care protocol, as well as the routine use of a citrate catheter lock and antibiotic ointment at the catheter exit‐site.

Some Kinetic Considerations in High Cut-Off Hemodiafiltration for Acute Myoglobinuric Renal Failure

The kinetics of myoglobin in severe rhabdomyolysis and dialysis‐dependent myoglobinuric acute kidney injury (Mb‐AKI) is still not well elucidated, and more detailed knowledge could improve the now empiric use of rapid extracorporeal myoglobin removal by high cut‐off (HCO) hemodialysis treatments. Eighteen adult patients with severe dialysis‐dependent Mb‐AKI (median serum concentration of myoglobin 57.4 mg/L) participated in the prospective clinical study, assessing myoglobin kinetics during HCO hemodiafiltration (HCO HDF). High initial serum concentrations of myoglobin (median 57.4 mg/L), together with protracted myoglobin appearance in the blood, indicated a large accumulation of myoglobin in body fluids. Extra‐renal endogenous metabolic myoglobin clearance was delayed, with a slow exponential fall in serum myoglobin (t½ 35 h). A mean myoglobin clearance of 90–94 mL/min, a reduction ratio of 80%, and a rapid exponential fall (t½ 1 h) in serum and dialysate myoglobin were achieved by HCO HDF. Half of the cumulative myoglobin removal was accomplished in 3–5 h, with an additional removal of 7% each hour thereafter. A 2.4‐fold rebound in serum myoglobin followed the HCO procedures. Large amounts of myoglobin are released into the circulation, and its endogenous metabolic clearance in dialysis‐dependent Mb‐AKI is slow. Owing to its rapid and highly efficient myoglobin elimination, HCO HDF may represent a valuable tool in the initial management of severe Mb‐AKI, with a potential for earlier application in the future.

The Influence of Need-Based, Continuous, Low-Dose Iron Replacement on Hemoglobin Levels in Hemodialysis Patients Treated With Erythropoiesis-Stimulating Agents

Anemia is a common and important complication of chronic kidney disease. Treatment includes the use of erythropoiesis-stimulating agents (ESAs) and iron supplementation. However, the optimal schedule of iron supplementation remains to be defined. Thirty-one long-term hemodialysis patients were treated for 1 year (period 1) with ESAs and an intermittent pulse regimen consisting of 100 mg of iron sucrose administered after different dialysis sessions depending on serum ferritin and other laboratory values, but no more than once per week. During the next 3 years (period 2), patients were treated with ESAs and need-based, continuous, low-dose iron. Iron doses were determined on the basis of values and changes of serum ferritin and transferrin saturation every fourth week after the longest interdialysis time interval. Iron doses ranged from 10 to 60 mg of iron sucrose and were given 1-3 times per week. If grounded, we gradually reduced or even abolished the iron doses. A significant increase in the hemoglobin concentration and hematocrit during period 2 in comparison with period 1 was observed. The use of ESAs did not change significantly during period 2 in comparison with period 1, while the use of iron was significantly lower in period 2. Significantly lower values were obtained for serum ferritin, saturation of transferrin, serum iron, and total serum iron-binding capacity during period 2. A better response to ESA therapy (increase in hemoglobin and hematocrit) is achieved with need-based, continuous, low-dose iron replacement.

Membrane plasma exchange for the treatment of thrombotic thrombocytopenic purpura.

The aim of our report is to present our 11‐year experience with therapeutic membrane plasma exchange therapy for the treatment of idiopathic thrombotic thrombocytopenic purpura syndrome (TTP). In 56 patients, membrane plasma exchange therapy was initiated immediately and performed once or twice daily until the platelet count normalized. During each plasma exchange procedure, 1–1.5 plasma volumes (3606 ± 991 mL) were replaced with fresh frozen plasma. In 37 females and 19 males (44 ± 21 years), 1066 plasma exchange procedures were performed. The average duration of treatment was 23 ± 17 days. The average number of plasma exchanges was 19 ± 17 per patient. Renal impairment was detected in 36% of patients. At the initiation of plasma exchange treatment, the average platelet count was 31 ± 30 × 109/L and reached 199 ± 95 × 109/L thereafter. Fifty‐two of 56 (93%) patients demonstrated an excellent response to plasma exchange therapy, of whom 48 patients (86%) attained complete remission with a platelet count of more than 100 × 109/L. Four patients died soon after the initiation of plasma exchange therapy, when only 1–3 procedures had been performed. During the follow‐up period, six patients with complete remission had 1–5 subsequent relapses each year. One of them died of acute hemolytic reaction during the tapering of plasma exchange procedures. Three patients underwent additional splenectomy. Our experience with primary TTP supports the plasma exchange treatment with fresh frozen plasma as a mandatory, up‐to‐date therapy. Close monitoring during all 1066 procedures showed no serious side‐effects.

Surgical thrombectomy of thrombosed arteriovenous grafts by interventional nephrologists.

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.

Chronic Hemodialysis in Small Children.

When peritoneal dialysis is inapplicable, chronic hemodialysis (HD) becomes the only available treatment option in small children. Due to small patient size, central venous catheters (CVC) are mainly used for vascular access. Over the past 4 years, four children weighing less than 15 kg received chronic HD in our unit. A total of 848 dialysis sessions were performed. Altogether, 21 catheters were inserted. In all but one occasion, uncuffed catheters were used. Catheter revision was performed 15 times during the study period, either due to infection or catheter malfunction. The median number of catheter revisions and the median line survival was 3.0/patient‐year and 53 days (range; 6–373 days), respectively. There were 14 episodes of catheter related infections requiring 11 CVC revisions (78.6%). The median rate of line infections was 2.8/patient‐year. Chronic HD in small children is demanding and labor intensive. Issues pertain mainly to CVCs and limit its long‐term use.