Circadian rhythm of blood pressure in renal disease

Two-Day ABPM-Derived Indices and Mortality in Hemodialysis Patients

BACKGROUND

Blood pressure (BP) and arterial stiffness are known cardiovascular risk factors in hemodialysis (HD) patients. This study examines the prognostic significance of 44-hour BP circadian rhythm and ambulatory arterial stiffness index (AASI) in this population.

METHODS

A total of 80 HD patients underwent 44-hour ambulatory BP monitoring (ABPM) with a TM-2430 monitor during a standard midweek interdialytic interval and followed up for 4.5 ± 1.7 years. The end point was all-cause mortality.

RESULTS

About 76% of participants were hypertensive (40% uncontrolled), 62% were nondippers, and 23% risers during the first interdialytic day, whereas 73% and 44% in the second day, respectively. During follow-up, 31 patients (40%) died. These showed higher pulse pressure (PP) and AASI44 and AASI of the second interdialytic period. The incidence of all-cause mortality was higher in HD patients with AASI44 > median, i.e. >0.54 (interquartile range = 14) (54% vs. 28%, χ 2 = 5.3, P = 0.021) when compared with those with lower AASI44. Second, but not first-day ABPM-derived parameters, namely nondipping (log-rank χ 2 = 6.10, P = 0.0134) or reverse dipping status (log-rank χ 2 = 5.32, P = 0.210) and arterial stiffness index (log-rank χ 2 = 6.61, P = 0.0101) were significantly related to greater mortality.

CONCLUSIONS

These findings indicate a strong relationship between arterial stiffness and cardiovascular risk and support a wider use of 44-hour ABPM recording for risk stratification in HD patients.

Peripheral artery disease and blood pressure profile abnormalities in hemodialysis patients

BACKGROUND

Patients undergoing chronic hemodialysis (HD) are at increased risk for peripheral artery disease (PAD). Both ankle-brachial index (ABI) and ambulatory blood pressure monitoring (ABPM) in the interdialytic period have been shown to be strong predictors of all-cause mortality.

METHODS

This cross-sectional study investigated the relationship between ABPM profile and ABI in 81 HD patients. ABPM was measured throughout a 44-h midweek interdialytic period. Pre-dialysis ABI was evaluated with a BOSO ABI device. An ABI value <0.9 or ≥1.3 was defined as abnormal.

RESULTS

In the whole study group (72 % males, mean age 67 ± 14 years), there was an increase in BP (p < 0.05) and in systolic BP night/day ratio (n/dSR, p = 0.01) during the interdialytic period. Patients with abnormal ABI (n = 29) more frequently had a positive history for cerebrovascular accident and PAD and higher proBNP values than those with normal ABI (n = 52). No difference was detected among ABPM-derived components except for the n/dSR (p = 0.02). Patients with abnormal ABI showed a significantly increased n/dSR (p = 0.02) and ambulatory arterial stiffness index (AASI) (p = 0.006) on the second day compared to the first. Patients with n/dSR >1 during day 2 (n = 34) were older, showed significantly higher proBNP and AASI and were more likely to reveal abnormal ABI compared to those with a lower n/dSR (p = 0.006).

CONCLUSIONS

Abnormal ABI in HD patients is associated to changes in interdialytic ABPM pattern, namely higher n/dSR on day 2. These data may indicate the pathophysiological mechanisms underlying the worse outcome observed in HD patients.

Ambulatory blood pressure monitoring in chronic renal disease: technical aspects and clinical relevance

PURPOSE OF REVIEW

To evaluate the current value of ambulatory blood pressure monitoring in patients with chronic renal disease and end-stage renal disease.

RECENT FINDINGS

Ambulatory blood pressure monitoring has become an important tool in hypertension research and clinical practice. Its use in essential hypertension shows a strong predictive ability in the assessment of cardiovascular outcomes. In chronic renal failure and end-stage renal disease, the role of ambulatory blood pressure monitoring is still being actively evaluated, and available evidence shows that it is better than office blood pressure in predicting left ventricular hypertrophy and progression of renal dysfunction in patients with chronic renal failure. In end-stage renal disease, preliminary data suggest better prediction of mortality in hemodialysis patients in comparison with clinic blood pressures. The most conspicuous problems with the literature on this subject are small sample sizes and the paucity of longitudinal observational studies and intervention trials.

SUMMARY

Preliminary data and extrapolations from essential hypertension have justified a growing excitement about the use of ambulatory blood pressure monitoring in renal disease. However, further research will have to address the limitations of the available literature before generalization of its use is implemented.

Circadian pattern of blood pressure, heart rate, and double product in liver glycogen storage disease

The objective of this study was to determine systolic, diastolic, and mean arterial blood pressure (SBP, DBP, and MAP), heart rate (HR), double-product (DP: SBP x HR), and activity levels and their 24h pattern in liver glycogen storage disease (LGSD) patients. A case series of 12 (11 pediatric and one adult) diurnally active LGSD (seven type I, three type III, and two type IX) subjects were simultaneously assessed by 24h ambulatory blood pressure monitoring and wrist actigraphy. Nine subjects were judged to be hypertensive based on the criterion of an elevated 24h mean SBP and/or DBP being elevated beyond reference standards or the SBP and/or DBP load (percentage of time BP exceeds normal values) being greater than 25%. Two of the three other subjects, not viewed as hypertensive based on their 24h average SBP or DBP, exhibited daytime or nighttime SBP and/or DBP load hypertension. Each study variables displayed statistically significant (p < 0.001) group circadian rhythmicity. The SBP, DBP, and MAP displayed comparable 24h patterns of appreciable amplitude (total peak-trough variation equal to 17.7, 23.6, and 19.6%, respectively, of the 24h mean) with highest values (orthophase) occurring approximately 11 h after the commencement of daytime activity. The sleep-time trough (bathyphase) occurred approximately 4.5 h before morning awakening. The statistically significant (p < 0.006) circadian rhythms of HR (amplitude equal to 33.2% of the 24h mean) and DP (amplitude equal to 49.4% of the 24h mean) peaked earlier, approximately 7.4 h into the daytime activity span. The sleep-time trough occurred approximately 3 h before morning awakening. The 24h pattern in the cardiovascular variables was correlated with the 24h pattern of activity, with r ranging from 0.50 for DBP to 0.39 for HR.