Effects of nutritional parameters on nocturnal blood pressure in patients undergoing hemodialysis

Effects of Orthostatism and Hemodialysis on Mean Heart Period and Fractal Heart Rate Properties of Chronic Renal Failure Patients

The aim of this work was to evaluate the short-term fractal index (α₁ ) of heart rate variability (HRV) in chronic renal failure (CRF) patients by identifying the effects of orthostatism and hemodialysis (HD), and by evaluating the correlation between α₁ and the mean RR interval from sinus beats (meanNN). HRV time series were derived from ECG data of 19 CRF patients and 20 age-matched healthy subjects obtained at supine and orthostatic positions (lasting 5 min each). Data from CRF patients were collected before and after HD. α₁ was calculated from each time series and compared by analysis of variance. Pearson's correlations between meanNN and α₁ were calculated using the data from both positions by considering three groups: healthy subjects, CRF before HD and CRF after HD. At supine position, α₁ of CRF patients after HD (1.17 ± 0.30) was larger (P < 0.05) than in healthy subjects (0.89 ± 0.28) but not before HD (1.10 ± 0.34). α₁ increased (P < 0.05) in response to orthostatism in healthy subjects (1.29 ± 0.26) and CRF patients after HD (1.34 ± 0.31), but not before HD (1.25 ± 0.37). Whereas α₁ was correlated (P < 0.05) with the meanNN of healthy subjects (r = -0.562) and CRF patients after HD (r = -0.388), no significance in CRF patients before HD was identified (r = 0.003). Multiple regression analysis confirmed that α₁ was mainly predicted by the orthostatic position (in all groups) and meanNN (healthy subjects and patients after HD), showing no association with the renal disease condition in itself. In conclusion, as in healthy subjects, α₁ of CRF patients correlates with meanNN after HD (indicating a more irregular-like HRV behavior at slower heart rates). This suggests that CRF patients with stable blood pressure preserve a regulatory adaptability despite a shifted setting point of the heart period (i.e., higher heart rate) in comparison with healthy subjects.

The relationship between serum albumin levels and 24-h ambulatory blood pressure monitoring recordings in non-diabetic essential hypertensive patients

OBJECTIVES

The goal of this study was to evaluate the relationship between serum albumin levels and 24-hour ambulatory blood pressure monitoring (24-h ABPM) recordings in non-diabetic essential hypertensive patients.

METHODS

A total of 354 patients (mean [SD] age: 55.5 [14.3] years, 50% females) with essential hypertension and 24-h ABPM recordings were included. Patient 24-h nighttime and daytime ABPM values, systolic and diastolic dipping status and average nocturnal dipping were recorded. The correlations between serum albumin levels and nocturnal systolic and diastolic dipping were evaluated, and correlates of average nocturnal systolic dipping were determined via a linear regression model.

RESULTS

Overall, 73.2% of patients were determined to be non-dippers. The mean (SD) levels of serum albumin (4.2 [0.3] g/dL vs. 4.4 [0.4] g/dL, p<0.001) and the average nocturnal systolic (15.2 [4.8] mmHg vs. 0.3 [6.6] mmHg, p<0.001) and diastolic dipping (4.2 [8.6] mmHg vs. 18.9 [7.0] mmHg, p<0.001) were significantly lower in non-dippers than in dippers. A significant positive correlation was noted between serum albumin levels and both systolic (r=0.297, p<0.001) and diastolic dipping (r=0.265, p<0.001). The linear regression analysis revealed that for each one-unit increase in serum albumin, the average nocturnal dip in systolic BP increased by 0.17 mmHg (p=0.033).

CONCLUSION

Our findings indicate an association between serum albumin levels and the deterioration of circadian BP rhythm among essential hypertensive patients along with the identification of a non-dipper pattern in more than two-thirds of patients. Our findings emphasize the importance of serum albumin levels, rather than urinary albumin excretion, as an independent predictor of nocturnal systolic dipping, at least in non-diabetic essential hypertensive patients with moderate proteinuria.

Profile of interdialytic ambulatory blood pressure in a cohort of Chinese patients

Management of hypertension is one of the fundamental interventions in dialysis patients. However, the profile of interdialytic blood pressure (BP) in Chinese dialysis patients remains elusive. We aim to investigate this issue as well as the effect of antihypertensive medication in this population. We performed 44-h ambulatory BP in 90 patients on maintenance hemodialysis. Patients were classified as 'dipping', 'non-dipping' or 'reverse-dipping' based on night/day ratio (N/D) of systolic BP on nondialysis day. The prevalence of blunted circadian BP pattern was strikingly high (92.2%), with more than half of the patients (55.6%) classified as reverse-dipping. There was a close association between high erythropoietin (EPO) dose used and deteriorated circadian rhythm. Patients in the dipping group also displayed a dipping state for heart rate (HR) compared with the other two groups (N/D of HR: 81.5 ± 6.6 vs 92.1 ± 6.0 and 91.3 ± 10.7, P=0.02). Only 26.7% patients had a controlled nocturnal BP. Patients with bedtime dosing had lower N/D of systolic BP compared with patients without (100.1 ± 7.0 vs 105.2 ± 7.1, P=0.01). Non-dipping and reverse-dipping are highly prevalent in Chinese patients. EPO use and autonomic dysfunction may contribute to the blunted circadian rhythm. More tightly control of nighttime BP is an urgent need and bedtime dosing may be beneficial.