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Assessment of Vascular Function in Patients With Chronic Kidney Disease
Published on: June 16, 2014
Blood pressure variability in CKD patients with and without nocturnal hypertension
Artemios G Karagiannidis1, Marieta P Theodorakopoulou2, Fotini Iatridi1
1First Department of Nephrology, Hippokration Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Insights
Nocturnal hypertension in chronic kidney disease (CKD) patients is linked to higher blood pressure variability (BPV) during 24-hour and daytime periods. This increased BPV may contribute to greater cardiovascular risk in these individuals.
Area of Science:
- Nephrology
- Cardiology
- Hypertension Research
Background:
- Nocturnal hypertension is common in chronic kidney disease (CKD) and a significant predictor of cardiovascular events.
- Elevated blood pressure variability (BPV) is also independently associated with adverse cardiovascular outcomes in CKD patients.
- Previous studies have not specifically examined short-term BPV differences between CKD patients with and without nocturnal hypertension.
Purpose of the Study:
- To investigate and compare short-term blood pressure variability (BPV) indices between CKD patients with and without nocturnal hypertension.
- To determine if differences in 24-hour, daytime, and nighttime BPV exist in relation to the presence of nocturnal hypertension in CKD.
Main Methods:
- Included 96 CKD patients (73 with nocturnal hypertension, 23 without).
- Utilized 24-hour ambulatory blood pressure monitoring.
- Calculated BPV indices including standard deviation (SD), weighted SD (wSD), coefficient of variation (CV), and average real variability (ARV) for systolic (SBP) and diastolic blood pressure (DBP) during 24-hour, daytime, and nighttime periods.
Main Results:
- Patients with nocturnal hypertension exhibited higher 24-hour wSD and ARV for SBP and DBP compared to those without.
- Higher daytime SD and ARV for SBP and DBP were observed in patients with nocturnal hypertension.
- No significant differences in nighttime BPV indices were found between the two groups.
Conclusions:
- CKD patients with nocturnal hypertension demonstrate significantly higher 24-hour and daytime blood pressure variability.
- The absence of significant differences in nighttime BPV suggests that elevated variability during waking hours contributes to cardiovascular risk in this population.
- Increased BPV, particularly during daytime, may be a key factor underlying the heightened cardiovascular risk associated with nocturnal hypertension in CKD.
Abstract:
Nocturnal hypertension is highly prevalent in patients with chronic kidney disease (CKD) and represents a strong predictor of cardiovascular events. Increased blood pressure variability (BPV) is also independently associated with cardiovascular events in these patients. Differences in short-term BPV indices between CKD patients with and without nocturnal hypertension have not been previously studied. This study included 96 patients (73 with and 23 without nocturnal hypertension) who underwent 24-h ambulatory BP measurement. Standard deviation (SD), weighted SD (wSD), coefficient of variation (CV), and average real variability (ARV) of systolic (SBP) and diastolic blood pressure (DBP) were calculated using validated formulas for the 24-h and the respective daytime (07:00-23:00) and nighttime (23:00-07:00) periods. 24-h, daytime and nighttime SBP and DBP were higher in patients with nocturnal hypertension. During the 24-h period, wSD and ARV for 24-h SBP (wSD, 14.0 ± 3.8 vs 11.7 ± 3.1 mmHg, p = 0.009; ARV, 10.5 ± 2.7 vs 9.2 ± 1.9 mmHg, p = 0.035) and 24-h DBP were higher in patients with nocturnal hypertension. Regarding the daytime period, patients with nocturnal hypertension presented higher daytime SD and ARV for SBP (SD, 14.8 ± 4.0 vs 13.0 ± 3.6 mmHg, p = 0.008; ARV; 10.5 ± 3.2 vs 9.1 ± 2.0 mmHg, p = 0.016) and DBP, with daytime SBP and DBP CV being numerically but not significantly higher (p = 0.110 and p = 0.08 respectively). During the nighttime period, no significant differences between groups were present for all nighttime BPV indices. In conclusion, CKD patients with nocturnal hypertension have higher systolic and diastolic BPV indices during the 24-h and daytime periods, but not the nighttime period. These findings signify that increased BPV may be responsible for higher cardiovascular risk in CKD patients with compared to those without nocturnal hypertension.
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