Influence of interdialytic weight gain on blood pressure in hemodialysis patients

The role of fluid overload in the pathogenesis of hypertension in hemodialysis patients is not clear. One problem is the lack of techniques to determine the fluid state. Recent new noninvasive techniques have become available which make it possible to accurately determine the dry weight in these patients. Therefore, we studied the influence of interdialytic weight gain on interdialytic blood pressure in 10 normotensive and 10 hypertensive hemodialysis patients without antihypertensive medication. The dry weight was determined with echography of the vena cava. The blood pressure was measured during 2-day and 3-day interdialytic periods using Spacelabs 90207 ambulatory blood pressure monitors. Mean systolic and diastolic blood pressures of the last day of the interdialytic period were compared with mean systolic and diastolic blood pressures of the 1st day of the interdialytic period. Although the interdialytic weight gain in the normotensive and hypertensive patients was greater during the 3-day than during the 2-day interdialytic period, the interdialytic systolic and diastolic blood pressure changes were not greater during the 3-day period. Also, the interdialytic blood pressure rise did not correlate significantly with weight gain, neither in the normotensive nor in hypertensive patients. No significant interdialytic blood pressure changes were found between the normotensive and the hypertensive patients. We conclude that fluid overload does not seem to play a major role in interdialytic blood pressure control in normotensive and hypertensive hemodialysis patients.