Blood Pressure Variability in CKD: Treatable or Hypertension's Homocysteine?

The roles of sodium and volume overload on hypertension in chronic kidney disease

Chronic kidney disease (CKD) is associated with increased risk of cardiovascular (CV) events, and the disease burden is rising rapidly. An important contributor to CV events and CKD progression is high blood pressure (BP). The main mechanisms of hypertension in early and advanced CKD are renin-angiotensin system activation and volume overload, respectively. Sodium retention is well known as a factor for high BP in CKD. However, a BP increase in response to total body sodium or volume overload can be limited by neurohormonal modulation. Recent clinical trial data favoring intensive BP lowering in CKD imply that the balance between volume and neurohormonal control could be revisited with respect to the safety and efficacy of strict volume control when using antihypertensive medications. In hemodialysis patients, the role of more liberal use of antihypertensive medications with the concept of functional dry weight for intensive BP control must be studied.

Effect of Improving Volume Overload on Home Blood Pressure Variability in Hemodialysis Patients

Blood pressure variability is an independent predictor of adverse clinical events in hemodialysis patients. Volume overload is one of the most important factors affecting blood pressure homeostasis. In the present study, we explored the effects of dry weight reduction on home blood pressure variability in volume overload hemodialysis patients. Hemodialysis patients with volume overload had their dry weight gradually decreased under the guidance of bioimpedance methods, which was represented by calf-bioimpedance ratio (Calf-BR). Home blood pressure was measured on waking up and at bedtime for 1 week at baseline and at the end of the two-month study. Coefficient of variation was used to define home blood pressure variability. Thirty-eight hemodialysis patients had their dry weight significantly decreased from 60.7 ± 11.3 to 59.6 ± 10.7 kg (P = 0.003) accompanied with a significant reduction in calf-BR (0.828 ± 0.023 vs. 0.786 ± 0.020, P<0.001). The systolic and diastolic blood pressure decreased significantly. Moreover, the whole-day, morning, and evening systolic blood pressure variability gradually and significantly decreased by the end of the study (5.6 ± 2.1% versus 4.0 ± 1.7%, P<0.001; 7.7 ± 3.5% vs. 6.3 ± 2.7%, P = 0.005; 7.5 ± 2.8% vs. 5.9 ± 2.3%, P = 0.002, respectively). Diastolic blood pressure variability parameters were unchanged. The interdialytic weight gain and the incidence of adverse events were similar throughout the study period. Gradual dry weight reduction by bioimpedance methods improved home blood pressure variability in hemodialysis patients with chronic fluid overload.