Achieving high convective volume in hemodiafiltration: Lessons learned after successful implementation in the HDFit trial

Abstract

Background and objectives High‐volume online hemodiafiltration (OL‐HDF) associates with improved outcomes compared to hemodialysis (HD), provided adequate dosing is achieved as estimated from convective volume (CV). Achievement of high CV and its impact on biochemical indicators following a standardized protocol converting HD patients to OL‐HDF has not been systematically reported. We assessed the success of implementation of OL‐HDF in clinics naïve to the modality. Design, setting, participants, and measurements We analyzed the results of the implementation of postdilution OL‐HDF in patients randomized to the HDF arm of a clinical trial (impact of hemoDiaFIlTration on physical activity and self‐reported outcomes: a randomized controlled trial (HDFit) trial [http://clinicaltrials.gov:NCT02787161]). The day before randomization of the first patient to OL‐HDF at each clinic staff started a 3‐day in‐person training module on operation of Fresenius 5008 CorDiax machine in HDF mode. Patients were converted from high‐flux HD to OL‐HDF under oversight of trainers. OL‐HDF was performed over a 6‐months follow‐up with a CV target of 22 L/treatment. We characterized median achieved CV >22 L/treatment record and analyzed the impact of HDF on biochemical variables. Results Ninety‐seven patients (mean age 53 ± 16 years, 29% with diabetes, and 11% had a catheter) from 13 clinics randomized to the OL‐HDF arm of the trial were converted from HD to HDF. Median CV > 22 L/treatment was achieved in 99% (94/95) of OL‐HDF patients throughout follow‐up. Monthly mean CV ranged from 27.1 L to 27.5 L. OL‐HDF provided an increased single pool Kt/V at 3‐months (0.2 [95% CI: 0.1–0.3]) and 6‐months (0.2 [95% CI: 0.1–0.4]) compared to baseline, and reduced phosphate at 3‐months (−0.4 mg/dL [95% CI: −0.8 to −0.12]) of follow‐up. Conclusions High‐volume online hemodiafiltration was successfully implemented with 99% of patients achieving protocol defined CV target. Monthly mean CV was consistently >22 L/treatment during follow‐up. Kt/V increased, and phosphate decreased with OL‐HDF. Findings resulting from a short training period in several dialysis facilities appear to suggest HDF is an easily implementable technique.

Why and how high volume hemodiafiltration may reduce cardiovascular mortality in stage 5 chronic kidney disease dialysis patients? A comprehensive literature review on mechanisms involved

“…[15][16][17] Successful clinical implementation of online HDF took less than 3 days in naïve centers, as recently shown in a large prospective study. 18 HDF is potentially associated with several clinical benefits, including better hemodynamic stability and improved patient perception but importantly with improved longer-term patient outcomes, especially with higher convective volume exchanges. 19 These findings have been largely documented in clinical cases series and in large cohort studies including randomized prospective interventional trials provided the adequate dosing was delivered.…”

Beta-2 microglobulin removal with postdilution online hemodiafiltration - comparison of three different dialysis membranes

“…Conventional HD with high-flux membranes has very limited efficiency in removing larger middle molecules [1]. Modalities employing convective transport, such as online hemodiafiltration (OL-HDF), enable enhanced removal of large uremic toxins, thus achieving cardioprotective effect and improving outcomes for HD patients [6,7,8]. The efficiency of HDF in middle molecules removal depends on the overall convective volume (Vconv), which is related to vascular access blood flow (Qavf), effective blood flow (Qb), and membrane properties [6,7,8].…”

“…Modalities employing convective transport, such as online hemodiafiltration (OL-HDF), enable enhanced removal of large uremic toxins, thus achieving cardioprotective effect and improving outcomes for HD patients [6,7,8]. The efficiency of HDF in middle molecules removal depends on the overall convective volume (Vconv), which is related to vascular access blood flow (Qavf), effective blood flow (Qb), and membrane properties [6,7,8]. Contemporary HDF membranes have a high ultrafiltration coefficient (Kuf  40 ml/h x mmHg), sieving coefficient for β2m >0.60, sieving coefficient for albumin <0.01 to prevent albumin loss over 4.0 g/4hr session, internal capillary diameter >200 µm and capillary density per surface area >11,000 allowing for dialysate flow (Qd) of 400-500 mL/min [6,7,8].…”

“…The efficiency of HDF in middle molecules removal depends on the overall convective volume (Vconv), which is related to vascular access blood flow (Qavf), effective blood flow (Qb), and membrane properties [6,7,8]. Contemporary HDF membranes have a high ultrafiltration coefficient (Kuf  40 ml/h x mmHg), sieving coefficient for β2m >0.60, sieving coefficient for albumin <0.01 to prevent albumin loss over 4.0 g/4hr session, internal capillary diameter >200 µm and capillary density per surface area >11,000 allowing for dialysate flow (Qd) of 400-500 mL/min [6,7,8]. Vconv represents the sum of the substitution volume (Vsubs) and the net ultrafiltration volume (Vnuf) achieved to correct extracellular fluid overload.…”

“…Vconv represents the sum of the substitution volume (Vsubs) and the net ultrafiltration volume (Vnuf) achieved to correct extracellular fluid overload. Vconv target should be ≥ 22 L per dialysis session to achieve a convection dose target [6,7,8].…”