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Pressor responses to hyperventilation in elderly subjects differentiate essential from secondary hypertension

100%

Fontana F. , Bernardi P. , Pizzi C. , Pich E.

Open Medicine

2009

tom 4

nr 1

17-25

We evaluated pressor responses to the hyperventilation test in elderly normotensive (n=43, mean age 82 ± 5 years) and elderly hypertensive subjects (n=45 with essential hypertension, mean age 82 ± 2 years, and n=49 with secondary hypertension, mean age 82 ± 3 years). Hyperventilation did not change blood pressure (BP) in normotensive and secondary hypertensive subjects, whereas it decreased BP in essential hypertensives. Hierarchical cluster analysis based on BP responses to hyperventilation disclosed three groups of subjects in each population: group 1 exhibited a reduction in BP (essential hypertensives: 76%), group 2 no change (normotensives: 70%, secondary hypertensives: 76%), and group 3 an increase (normotensives: 19%, essential hypertensives: 13%, secondary hypertensives: 14%). Ambulatory BP monitoring found significant differences in pressor daytime profiles of hypertensive patients according to pressor responses to hyperventilation showing wide fluctuations in group 1 and 3 patients. Interestingly, the peak ambulatory SBP values correlated to the pre-hyperventilation SBP values in group 1, and to the hyperventilation peak SBP values in group 3. In conclusion: 1) Aging decreases reactivity to respiratory alkalosis in elderly normotensives; 2) hyperventilation induces significant pressor changes frequently in essential hypertension, but rarely in secondary hypertension; 3) the significant pressor responses to hyperventilation reflect the daytime pressor profiles predicting the highest daily fluctuations of BP values.

β-Endorphin in pressor response to hyperventilation in elderly patients with essential and secondary hypertension

88%

Fontana F. , Bernardi P. , Pizzi C. , Toro R. , Spampinato S.

Open Medicine

2008

tom 3

nr 1

55-63

It has been observed that a distinct blood pressure (BP) response to prolonged and forced hyperventilation in adult patients with essential hypertension is associated with significant changes in plasma catecholamine and β-endorphin levels. This paper investigated whether hemodynamic and neuro-endocrine responses to hyperventilation in elderly patients with essential hypertension (n = 39, mean age 81 ± 3 years) differ from those in elderly patients with secondary hypertension (isolated systolic hypertension, bilateral chronic nephropathy, nephroangiosclerosis, diabetic nephropathy and hyperparathyroidism) (n = 39, mean age 80 ± 1 years). Plasma β-endorphin levels were normal in patients with essential hypertension and increased in patients with secondary hypertension. Plasma norepinephrine levels were normal in both populations. Hyperventilation decreased BP and norepinephrine levels and increased β-endorphin levels in essential hypertensive patients, whereas it did not significantly change BP or neuro-hormonal levels in secondary hypertensive patients. Hierarchical cluster analysis based on BP response to hyperventilation disclosed a sub-group of essential hypertensive patients with the highest basal levels of norepinephrine and the lowest β-endorphin levels, in whom the BP decrease following hyperventilation was correlated with the decrease in norepinephrine and increase in β-endorphin levels. This suggests that b-endorphin may be involved in modulating sympatho-adrenergic activity in elderly patients with essential hypertension.