Kidney Week

Abstract: TH-OR090

Effect of Treatment Duration on Middle-Molecule Removal in Expanded Hemodialysis vs. High-Volume Hemodiafiltration: The REMOV-HDx Crossover Study

Session Information

• Rethinking Hemodialysis: Innovation Across the Care Continuum
  October 22, 2026 | Location: Mile High Ballroom 1A, Convention Center
  Abstract Time: 05:50 PM - 06:00 PM

Category: Dialysis

• 801 Dialysis: Hemodialysis and Frequent Dialysis

Authors

• Zuñiga Gonzalez, Erick Yasar, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Erick Yasar Zuñiga Gonzalez, MD, MEd

• Mercado Hernández, Yazmin Alejandra, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Yazmin Alejandra Mercado Hernández, MD

• Esteban-Prado, Alejandro, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Alejandro Esteban-Prado, MD

• Asuncion Tomas, Jessica Maribel, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Jessica Maribel Asuncion Tomas, LPN/VN, RN

• Cruz Rivera, Cristino, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Cristino Cruz Rivera

• Correa-Rotter, Ricardo, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Ricardo Correa-Rotter, MD

• Vega, Olynka, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Olynka Vega, MD, MS

Background

Expanded hemodialysis (HDx) uses medium cut-off (MCO) membranes to achieve middle-molecule clearance without a validated dose metric beyond session duration. Whether treatment time meaningfully modulates HDx removal or an earlier saturation plateau exists remains unresolved.

Methods

Prospective crossover trial in 15 maintenance HD patients randomized to four prescriptions: HDx (Theranova 400) at 180, 210, and 240 min, and high-volume OL-HDF (CordiaxFX100; mean convective volume 27.2 L/session). A Global Removal Score (GRS) was derived from reduction ratios of β₂-microglobulin (11.8 kDa), myoglobin (17.1 kDa), prolactin (23 kDa), and α₁-acid glycoprotein (41 kDa). A linear mixed-effects model adjusted for processed blood volume and vascular access recirculation. Dialysis parameters were standardized across arms (Qb: 370±23 ml/min; Qd: 550±25 ml/min).

Results

OL-HDF was superior to HDx 240 min (GRS difference +14.2%, p=0.003) and HDx 210 min (p=0.037). Extending HDx from 180 to 240 min yielded no significant incremental GRS gain. For middle molecules (β2m, Myoglobin, Prolactin), HDx removal reached a plateau at 180 min. For α₁-acid glycoprotein (41 kDa), removal showed progressive time-dependent increase, achieving equivalence with OL-HDF at 240 min (18.8%) [Figure 1A-B].

Conclusion

The convective gap between HDx and high-volume OL-HDF may be molecularly stratified. For middle molecules below 25 kDa, internal filtration saturates by 180 minutes and extended session time does not improve clearance. For larger middle molecules HDx at 240 min achieves comparable removal to OL-HDF. Global dose equivalence between these modalities cannot be assumed; prescription decisions should consider the molecular-weight profile of target uremic solutes.

Funding

• Private Foundation Support