Background: In hemodialysis patients, the intradialytic rise in blood pressure (BP) is associated with increased mortality risk. However, the mechanisms of this adverse effect are not yet elucidated. This study examined whether intradialytic rise in BP is associated with increased arterial stiffness and wave reflections, which are powerful cardiovascular risk predictors in hemodialysis.
Methods: The pattern of intradialytic hemodynamic response was evaluated in 70 prevalent hemodialysis patients, by measuring seated brachial BP before and after the mid-week dialysis session. All patients had pre- and post-dialysis determination of aortic pulse wave velocity (PWV) and heart rate-adjusted augmentation index [AIx(75)], as measures of arterial stiffness and wave reflections, with the Sphygmocor device.
Results: Intradialytic rise in brachial systolic BP (SBP) was evident in 17 patients, whereas intradialytic change in SBP (ΔSBP) of -10 to 0 mmHg was observed in 23 and ΔSBP greater than -10 mmHg in 30 patients. Participants with intradialytic SBP rise had significantly higher pre-dialysis aortic PWV (10.4 ± 1.6 vs 8.3 ± 1.9 vs 9.4 ± 2.4 m/s, P < 0.01) and AIx(75) (28.1 ± 7.3 vs 21.7 ± 8.6 vs 25.8 ± 8.2%, P < 0.05) than those experiencing intradialytic ΔSBP of -10 to 0 and greater than -10 mmHg, respectively. Patients with rise in SBP during dialysis exhibited also lower intradialytic reduction in AIx(75) (-1.5 ± 4.9 vs -5.4 ± 5.9 vs -6.7 ± 5.3%, P < 0.001).
Conclusions: This study shows that aortic stiffness and wave reflections are higher and not affected by dialysis procedure in patients with intradialytic SBP rise, suggesting that accelerated arteriosclerosis may be one possible explanation for the heightened cardiovascular risk associated with intradialytic hypertension.
Keywords: Arterial stiffness; Augmentation index; Intradialytic BP; Pulse wave velocity; Wave reflections.