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Effect of sympathetic and plasma renin activity on hemodialysis hypertension
D Grekas1, I Kalevrosoglou, M Karamouzis
1First Medical Department, University Hospital AHEPA, Thessaloniki, Greece.
Insights
Sympathetic activity, measured by plasma catecholamines, does not appear to be linked to hypertension in hemodialysis patients. Further research is needed to understand blood pressure control in this population.
Area of Science:
- Nephrology
- Cardiovascular Physiology
- Endocrinology
Background:
- Poor blood pressure control in hemodialysis (HD) patients remains poorly understood.
- Excess weight and achieved dry weight do not differ between hypertensive and normotensive HD patients.
- Sympathetic nervous system activity is investigated as a potential factor in HD hypertension.
Purpose of the Study:
- To investigate the role of sympathetic activity and plasma renin-aldosterone in hemodialysis (HD) hypertension.
- To compare these factors between hypertensive and normotensive HD patients.
Main Methods:
- Studied 10 hypertensive and 10 normotensive HD patients.
- Measured plasma aldosterone (ALDO), renin activity (PRA), adrenaline, and noradrenaline before and after HD.
- Analyzed one month of dialysis records, including mean arterial blood pressure (MAP).
Main Results:
- Hypertensive patients showed higher pre-dialysis plasma renin activity (PRA) and plasma aldosterone (ALDO) compared to normotensive patients.
- Plasma ALDO levels correlated significantly with fluid volume removed by ultrafiltration (p < 0.05).
- Neither PRA nor plasma catecholamine levels (adrenaline, noradrenaline) correlated with mean arterial blood pressure (MAP) or body weight changes.
Conclusions:
- Sympathetic activity, indicated by plasma catecholamine levels, is not associated with hemodialysis hypertension.
- The findings suggest that other mechanisms may be responsible for hypertension in HD patients.
Background:
The reasons for poor control of blood pressure in hemodialysis (HD) patients are not clear, while patients have achieved their desirable dry weight and excess weight are not different between the hypertensive and normotensive patients. A link between sympathetic activity and HD hypertension could be an alternative explanation.
Patients And Methods:
We studied the effect of sympathetic and plasma renin-aldosterone activity of 10 hypertensive patients, 5 men and 5 women, aged from 30 to 60 years. The results were compared to those of another 10 normotensive hemodialysis patients. Blood samples were taken before HD and at the end of a 4-hour HD session for plasma aldosterone (ALDO), renin activity (PRA), adrenaline and noradrenaline determination. One month dialysis records, which includes 13 dialysis sessions and 26 blood pressure readings for each patient were used, for pre-dialysis and post dialysis mean arterial blood pressure (MAP) measurement.
Results:
Pre-dialysis plasma adrenaline was 124.12 +/- 12.93 pg/ml vs. 121.12 +/- 14.71 pg/ml and plasma noradrenaline was 260.88 +/- 140.86 pg/ml vs. 138.11 +/- 122 +/- 32 pg/ml for hypertensive and normotensive patients, respectively. Post-dialysis plasma adrenaline and noradrenaline levels were 119.37 +/- 8.81 pg/ml vs. 120.62 +/- 15.35 pg/ml and 210.44 +/- 126.71 pg/ml vs. 94.88 +/- 64.05 pg/ml for hypertensive and normotensive patients, respectively. Pre-dialysis PRA was 8.70 +/- 6.37 ng/ml/h vs. 2.77 +/- 1.8 ng/ml/h and plasma ALDO was 457.07 +/- 245.54 pg/ml vs. 197.74 +/- 87.46 pg/ml for hypertensive and normotensive patients, respectively. Pre-MAP was 109.76 +/- 5.21 mmHg vs. 99.28 +/- 7.13 mmHg and post-MAP was 107.22 +/- 6.74 mmHg, vs. 91.61 +/- 7.27 mmHg for hypertensive and normotensive patients, respectively. Plasma ALDO and fluid volume removed by ultrafiltration were found to be significantly correlated (p < 0.05). PRA and plasma adrenaline-noradrenaline levels were not correlated with MAP or body weight alterations.
Conclusions:
It is suggested that sympathetic activity, as it was expressed by plasma catecholamine alterations, is not associated with hemodialysis hypertension.