MO805: Combination of Conventional Haemodialysis with Haemoperfusion: Does it Provide any Benefits to Haemodialysis Patients?

BACKGROUND AND AIMS

Conventional haemodialysis (HD) with low-flux membranes does not provide adequate middle molecular weight (MMW) clearance of uremic toxins [1]. The potential for better removal of parathyroid hormone (PTH) and β2-microglobulin (β2M) was investigated using a combination of low-flux HD and haemoperfusion (HP) (HD + HP).

METHOD

A total of 16 stable HD male patients, free of infections, malignancies or haematological disorders, under usual medications for anaemia and hyperparathyroidism, treated with low-flux polysulfone membranes, were randomized into two groups: group A (GA) included eight patients under HD + HP and group B (GΒ) included eight patients under HD only. In GA patients, a type HA130 HP cartridge was connected in parallel to the dialyzer, once a week for the first month, once every 2 weeks for the second month and once a month for the next 4 months. A third group C (GC) was also studied, consisting of eight males undergoing online haemodiafiltration (OL-HDF). In all three groups, serum β2M and iPTH levels were determined at months 0 and 6, before (preD) and after (postD) the mid-week session.

RESULTS

Serum preD-β2M levels were similar in groups A and B at month 0 (44.1 ± 8.6 versus 34.6 ± 16.2 mg/L;  P = NS) and at month 6 (46.1 ± 7.6 versus 41.1 ± 18.9 mg/L;  P = NS). In GC, preD–β2M values were lower compared with GA at month 0 (31.1 ± 4.2 mg/L;  P = .008) and at month 6 (33.8 ± 6.82 mg/L;  P = .02), and postD–β2M values decreased significantly at month 0 (7.4 ± 1.9 mg/L;  P < .001) and at month 6 (9.9 ± 3.8 mg/L;  P < 0.001). The reduction was maintained, with no difference between month 0 and month 6. An improvement/decrease in β2M values was observed between month 0 and month 6 only in GA (–5.8 ± 7. 2 versus 1.8 ± 5 mg/L; P = .03) but not in GB. PreD–iPTH values did not differ between groups A, B and C at month 0 (623 ± 432 versus 434 ± 350 versus 710 ± 286 pg/mL, respectively; P = NS) and at month 6 (758 ± 550 versus 383 ± 186 versus 559 ± 296 pg/mL, respectively; P = NS). PostD–iPTH values showed a decrease at month 6 in GA (from 758 ± 550 to 514 ± 474 pg/mL; P = .04) but not in GB and a mild decrease in GC (from 559 ± 296 to 363 ± 295 pg/mL; P = .05), with a marginal reduction improvement between month 0 and month 6 in GC (41 ± 55 versus 196 ± 87 pg/mL; P = .046).

CONCLUSION

OL-HDF is obviously the most effective method for the elimination of MMW uremic toxins [2]. Interestingly, the combination HD + HP seems to be more effective than low-flux HD alone [3], and it could be useful for specific patient cases in daily clinical practice.

MO837: Antibody Response to Mrna Covid-19 Vaccination in Haemodialysis Patients—A 7-Month Follow-Up

BACKGROUND AND AIMS

Haemodialysis (HD) patients have a great risk of severe infection from coronovirus 2(SARS-CoV-2). However, chronic kidney disease is often associated with immunodeficiency and other existing vaccines have reduced efficacy in HD patients [1]. Humoral immune response to SARS-CoV-2 vaccination in chronic HD patients was investigated during a period of 7 months.

METHOD

A total of 39 patients, M/F = 34/5, aged 71 (47–90) years, dialyzed for 55(18–286) months, vaccinated with mRNA Comirnaty vaccine (BNT 162b2; BioNTech & Pfizer) were studied. Patients received two initial vaccine doses in March and April 2021, respectively, and 24 out of 39 patients received a third dose in October 2021. We analyzed the antibody response to the spike (S) antigen of SARS-CoV-2 at 0, 1, 4 and 7 months (November) after second vaccine dose in all patients. We also compared serum antibody titers at time-point 7 between the 24/39 patients and 20 healthy age-matched individuals, also vaccinated with three doses at the same months.

RESULTS

At time-point 0, titers of S protein-targeting antibodies(S-Abs) were 5 ± 1 AU/mL. At 1 month S-Abs were < 50 AU/mL in 2 patients (5.15%), between 51 and 100 AU/mL in 2/39 patients (5.15%), between 101 and 1000(528 ± 292) AU/mL in 19/39 patients (48.7%) and between 1001 and 10 000 (4486 ± 2547) AU/mL in 13/39 patients(33.3%). S-Abs were higher than 10 000(14 516 ± 3062) AU/mL in 3/39 patients (7.7%) after previous infection. In the 36/39 patients not infected, at 4 months there was a significant titer decrease compared with values at 1 month: from 3108 ± 4361 to 1442 ± 4357 AU/mL; P < 0.001. At 7 months, the 24/39 patients vaccinated with the third dose showed increased titers in comparison with values at 1 and 4 months, respectively (9285 ± 11 202 versus 1957 ± 2763 AU/mL; P < 0.001 and versus 584 ± 669 AU/mL; P < 0.001, respectively). Among 15/39 patients who did not receive the third dose, 4/15 with an average titer of 739 AU/mL died from other causes, 3/15 with an average titer of 25 468 AU/mL were hospitalized for COVID-19 and discharged and 8/15 showed further titer decrease (2117 ± 4887 to 950 ± 1855 AU/mL; P = 0.031). After the third dose higher S-Abs were observed in healthy controls compared with HD patients (18 050 ± 15 374 versus 9285 ± 11 202 AU/mL; P = 0.032).

CONCLUSION

Healthy controls showed a better humoral immune response compared with patients. Two doses of mRNA BNT162b2 vaccine induced an initial satisfactory humoral response in HD patients but S-Abs significantly declined subsequently [2]. Humoral response was significantly better after the third dose and booster immunization seems necessary [3].

MO643: Haemoperfusion Combined with Standard Haemodialysis May Have a Beneficial Effect on Serum Beta-2 Microglobulin Levels in Chronic Haemodialysis Patients

BACKGROUND AND AIMS

Standard haemodialysis (HD) with low-flux membranes does not provide adequate middle molecular weight (MMW) clearance of uraemic toxins [1] and on-line haemodiafiltration (OL-HDF) may not be easily applicable and cost effective in some centres. We investigated whether low-flux conventional HD combined with hemoperfusion (HP) may offer any benefit regarding serum beta-2 microglobulin (β2M) levels as a surrogate of middle molecules in patients haemodialyzed for many years and we compared the method-combination with OL-HDF.

METHOD

We studied 24 stable anuric patients during 6 months, under standard medical therapy, aged 69 years (46–90), M: F = 20:4, on chronic HD for 84 (65–286) months, who formed three groups: A (GrA), B (GrB) and C (GrC). Each group included 8 age- and HD vintage-matched patients respectively. In GrA patients, a type HA130 cartridge for HP was connected in parallel to the low-flux polysulfone dialyzer and this combination of standard HD with HP (HD + HP) was used once a week for the first month, once every 2 weeks for the second month and once a month for the next 4 months. GrB patients underwent only standard HD treatment with low-flux polysulfone membranes and GrC patients were treated with OL-HDF. In all three groups serum β2M levels were determined at months 0 (M0) and 6 (M6), before (pre-dialysis, preD) and after (post-dialysis, postD) the second weekly session.

RESULTS

Serum preD β2M levels ​​were similar in GrA and GrB at M0 (44.1 ± 8.6 versus 34.6 ± 16.2 mg/L;  P = NS) and at M6 (46.1 ± 7.6 versus 41.1 ± 18.9 mg/L;  P = NS). In GrC, preD-β2M values were lower compared with GrA at both M0 (31.1 ± 4.2 mg/L;  P = .008) and M6 (33.8 ± 6.82 mg/L;  P = .02). In GrC, serum postD-β2M levels ​​decreased significantly at both M0 (7.4 ± 1.9 mg/L;  P < .001) and M6 (9.9 ± 3.8 mg/L;  P<.001). The postD reduction was maintained, with no difference between M0 and M6. An improvement/decrease in β2M values ​was observed only in GrA between M0 and M6 (−5.8 ± 7.2 versus 1.8 ± 5mg/L;  P = .03) but not in GBr.

CONCLUSION

OL-HDF is obviously the most effective method for elimination of MMW uraemic toxins and in particular β2M [2–3]. Interestingly, the combination HD + HP seems to be more effective than low-flux HD alone [4] and it could be useful for specific patient cases in daily clinical practice in order to prevent or delay the onset and deterioration of symptomatic amyloidosis. Possible result improvement with a more frequent use of HD + HP needs further investigation.

Swan-neck versus straight peritoneal dialysis catheter: Long-term effect on patient and method survival

Peritoneal dialysis (PD) is limited mainly by a higher technique failure rate as compared to hemodialysis (HD), catheter malfunction being an important reason. Intra- and extra-peritoneal catheter configuration may be associated with mechanical and infectious complications affecting method survival. We report our experience with two extra-peritoneal catheter configurations: the straight and the swan-neck (SN) catheters. A total of 85 consecutive patients, 58 males and 27 females were included in the study. Among them, 26 were diabetics; 52 were treated with automated PD (APD) and 33 with continuous ambulatory PD (CAPD). Straight catheters were used in 38 patients (straight group) and SN catheters in 47 patients (SN group). Straight catheters were mostly used in the first 6-year period while SN catheters in the last 6-year period. The baseline demographics were similar between the two groups. A significantly higher frequency of APD use was observed in SN group. Technique survival was better with SN versus straight (log-rank test, P = 0.01) while patient and catheter survival were similar. A better technique survival is noted in our group of patients with SN catheters. An additional factor could be the significantly higher frequency of APD use in this group. Changes in PD solutions’ composition could also contribute to improvement in technique survival. The outcome for patients and catheter types used was similar.

Neutrophil gelatinase-associated lipocalin (NGAL): a promising biomarker of contrast-induced nephropathy after computed tomography

Contrast-induced nephropathy (CIN) is a common cause of hospital-acquired acute kidney injury (AKI) and a source of significantly increased short- and long-term mortality. Studies of large cohorts have revealed that more than half of these cases are in subjects undergoing cardiac catheterization and intra-arterial coronary angiography, and nearly a third follow computed tomography (CT) scans. Neutrophil gelatinase-associated lipocalin (NGAL) represents an early predictive troponin-like biomarker for AKI. Its role in the timely diagnosis of CIN has already been examined in adults and children undergoing coronary angiography and a meta-analysis revealed a very good performance of plasma or urine NGAL in the prediction of CIN. Much of these data have been extrapolated to patients receiving intravenous (IV) contrast agent for CT scans, although major differences in patient populations, contrast volume administered and intra-procedural complications between the two settings exist. In this context, a recent prospective study by our group evaluated plasma NGAL, measured using standardized Τriage® NGAL test (Biosite Incorporated, San Diego, CA) at baseline and 6-h post-procedure, for early detection of CIN among hospitalized patients undergoing elective contrast-enhanced CT. CIN, defined as an increase in serum creatinine (SCr) of >25% or >0.5 mg/dL from baseline within 48-h post-procedure, was found in 8.51% of subjects. In contrast, significant elevation of plasma NGAL was found at 6-h post-procedure with excellent performance characteristics. This review presents the current status of NGAL in the prediction of CIN after IV contrast administration among hospitalized patients undergoing elective contrast-enhanced CT.

Plasma neutrophil gelatinase-associated lipocalin (NGAL) as an early predictive marker of contrast-induced nephropathy in hospitalized patients undergoing computed tomography

Background

Contrast-induced nephropathy (CIN) is a common cause of hospital-acquired acute kidney injury (AKI). Neutrophil gelatinase-associated lipocalin (NGAL) represents a promising biomarker for AKI. Its role in the early diagnosis of CIN has already been examined in adults and children undergoing coronary angiography. This study was designed to prospectively evaluate plasma NGAL compared with serum creatinine (SCr) for early CIN detection among hospitalized patients undergoing contrast-enhanced computed tomography (CT).

Methods

We prospectively enrolled consecutive hospitalized patients undergoing elective CT with intravenous (IV), low-osmolar contrast administration. Patients with pre-procedure SCr >150 μmol/L (1.7 mg/dL), congestive heart failure, haemodynamic instability, sepsis, or urinary tract infection were excluded. Plasma NGAL was measured using the standardized Triage^® NGAL test (Biosite Incorporated, San Diego, CA, USA) at baseline and 6 h post-procedure. SCr, blood urea nitrogen (BUN), albumin and sodium (Na) were measured and eGFR MDRD₄ was calculated at the same intervals, as well as at 24 and 48 h post-procedure. CIN was defined as an increase in SCr of >25% or >44 μmol/L (0.5 mg/dL) from baseline within 48 h post-procedure, in the absence of other obvious causes.

Results

Forty-seven patients, male/female 27/20, median age 68 (31–88) years, 16/47 diabetics, with baseline SCr 91.94 ± 20.33 μmol/L (1.04 ± 0.23 mg/dL) and eGFR MDRD₄ 68.40 ± 18.22 mL/min/1.73 m² were enrolled. A contrast volume of 120 mL (range 100–150 mL) was administered. CIN was found in four subjects (8.51%), but detection by SCr was only possible 24 h in 1 and 48 h post-procedure in three. In contrast, significant elevation of plasma NGAL was found at 6 h post-procedure in those with versus those without CIN (779.25 ± 361.49 versus 82.30 ± 40.64 ng/mL, P < 0.001). Using a cutoff value of 200 ng/mL, sensitivity, specificity and area under the receiver-operating characteristic (ROC) curve of 6-h plasma NGAL for CIN prediction were excellent (100, 100 and 1.00%, respectively). Subjects with CIN did not differ in baseline demographics, renal function and diabetes status compared with those without CIN. No differences in any variable were noted between diabetics and non-diabetics. Plasma NGAL at 6 h (R² = 0.24, P < 0.001) was found to be an independent predictor of CIN.

Conclusions

Plasma NGAL 6 h after contrast administration measured by the rapid, point-of-care Triage^® NGAL test appears to be a useful biomarker in the early prediction of CIN among hospitalized patients undergoing elective contrast-enhanced CT. However, the small sample size and the very small number of CIN events are important limitations. In any case, according to our evaluation, CIN incidence in this well-controlled population underlines the importance of early detection by an adequate and simple procedure such as the 6-h plasma NGAL test.