Dry-weight: a concept revisited in an effort to avoid medication-directed approaches for blood pressure control in hemodialysis patients

Abstract

Background and objectives: Achieving and maintaining dry-weight appears to be an effective but forgotten strategy in controlling and maintaining normotension among hypertensive patients on hemodialysis.

Methods: Qualitative review of literature to define dry-weight and its utility in achieving blood pressure control.

Results: The concept of dry-weight has evolved over time and its definition has changed. One such definition defines dry-weight as the lowest tolerated postdialysis weight achieved via gradual change in postdialysis weight at which there are minimal signs or symptoms of hypovolemia or hypervolemia. Although clinical examination does not perform well in detecting latent increase in dry-weight, several technologies such as relative plasma volume monitoring and body impedance analysis are emerging that may help in assessing dry-weight in the future. Sodium restriction is a modifiable risk factor that can lead to better blood pressure (BP) control. However, dietary sodium restriction requires lifestyle modifications that are difficult to implement and even harder to sustain over the long term. Restricting dialysate sodium is a simpler but underexplored strategy that can reduce thirst, limit interdialytic weight gain, and assist the achievement of dry-weight. Achievement of dry-weight can improve interdialytic BP, reduce pulse pressure, and limit hospitalizations.

Conclusions: Avoiding medication-directed control of BP may enhance the opportunity to probe dry-weight, facilitate removal of volume, and limit the risk for pressure-volume overload, which may be a significant concern leading to myocardial remodeling in the hemodialysis patient. Probing dry-weight among patients with ESRD has the potential to improve dismal cardiovascular outcomes.

Figure 1.

Example of RPV monitoring as an indicator of dry-weight. A 42-year-old black man with ESRD on chronic hemodialysis for 8 years treated with four antihypertensive medications consented to participate in the DRIP trial after he was noted to be hypertensive. Interdialytic ambulatory BP monitoring revealed a BP value of 149/89 mmHg. At baseline, RPV monitoring demonstrated no change in RPV. Dry-weight was probed in the subsequent 8 weeks. He lost 2.0 kg of postdialysis weight from 62.0 to 60.0 kg. At 8 weeks, RPV monitoring revealed a 3.15% reduction in RPV per hour. Interdialytic ambulatory BP improved to 125/77 mmHg. RPV monitoring may be a useful tool to assess dry-weight.