Endothelin in mild to moderate essential hypertension: relationship between ambulatory and clinic blood pressure values.

We investigated in a post hoc analysis the relationship between plasma endothelin (ET-1) levels (immunoreactive ET-1-like material: ir-ET-1) with both casual and noninvasive 24h ambulatory blood pressure monitoring (24h ABPM) values in EH. Fifteen uncomplicated EH patients (casual supine DBP > or = 100 mmHg), 10 males, age 54 +/- 6 years, 13 previously treated, enrolled in an antihypertensive drug trial (casual DBP > or = 100 mmHg), were evaluated. After a four week single-blind placebo wash-out period, measurements of supine casual SBP and DBP (three consecutive readings) and a 24h ABPM (Spacelabs 90207; automatic reading every 15 minutes) were carried out. Plasma ir-ET-1 was measured by radioimmunoassay kit (Amersham, UK). Pearson correlation coefficient tests were used for statistical evaluations. Mean (SD) casual SBP/DBP values were 166(5)/104(2) mmHg. The 24h ABPM mean values were 148(7)/87(3) mmHg. Daytime (07.00-23.00h) and nighttime (23.00-07.00h) SBP/DBP were 153(7)/91(3) and 137(10)/78(5) mmHg, respectively. Plasma ir-ET-1 levels were 0.9(0.5) pmol/l (range 0.3-2.1 pmol/l). Plasma ir-ET-1 was not correlated with casual SBP and DBP, age, serum creatinine and duration of EH. Positive and significant correlations were observed with 24h SBP (r = 0.59), daytime SBP (r = 0.58), nighttime SBP (r = 0.53) and DBP (r = 0.60). Unlike casual BP, ABPM mean values correlate positively with plasma ir-ET-1 in mild to moderate EH.