Revisiting Frontiers of Tolerability and Efficacy in Renal Replacement Therapy

2014 
Clinical outcomes associated with dialysis therapies depend on the prescribed treatment modality and conditions of treatment delivery. Prescribing dialysis therapy to patients with chronic kidney failure requires considering an impressive array of patientand technology-related factors, not to mention a variety of care practices. The study by Cornelis et al in this issue of AJKD examines the combined effects of 2 of the most widely debated and fundamental modifiable factors of the hemodialysis (HD) prescription: treatment modality and treatment duration. Most patients today are treated with high-flux rather than low-flux HD, which reflects the recognition that large, and not just small, uremic toxins must be removed to treat patients with chronic kidney failure. Hemodiafiltration (HDF), an extension of high-flux HD, is an alternative treatment modality that further increases the removal of larger uremic toxins by enhancing convective clearance. The second modifiable factor, treatment duration, has been a subject of debate since the early days of dialysis therapy, with most nephrologists of the opinion that patients derive the greatest benefit from longer and more frequent dialysis sessions. Cornelis et al explored the interaction of treatment modality and duration with a 232 factorial crossover study design that used each patient as his or her own control. Interventions included duration of the dialysis session (short [4 hours] vs long [8 hours]) and type of solute flux (diffusive flux using high-flux HD vs enhanced convective flux using HDF; in both cases, high-flux membrane dialyzers were used). The primary outcomes were hemodynamic tolerance and solute mass transfer as surrogate markers of the combined effect of time and solute flux prescription. Hemodynamic changes were used as outcome parameters for assessing the tolerability of both treatment time (short vs long) and modality (high-flux HD vs HDF). Hemodynamic assessment was performed using conventional measures such as relative blood volume changes, intermittent blood pressure, ultrafiltration, and weight loss, as well as more sophisticated markers like cardiac output, pulse wave velocity analysis, and microcirculation changes. As expected, ultrafiltration rate (in milliliters per kilogram per hour) was reduced by w50% in both modalities when long treatment times were used. Importantly, thermal balance was matched in the 4 treatment schedules, which suppressed this confounding factor in HDF. Clinical tolerance was not reported.
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    13
    References
    4
    Citations
    NaN
    KQI
    []