Nocturnal hypertension and sleep apnea: effect of the ACE inhibitor cilazapril on apnea-induced blood pressure increases during sleep]

The nocturnal increases in blood pressure in cases of obstructive sleep apnea are discussed as causes in connection with increased cardiovascular mortality in sleep apnea. Previous antihypertension therapy studies revealed the antihypertensive action of the ACE inhibitor cilazapril averaged over NREM (NR) and REM sleep (R). In the present study, the effect of this drug on the blood pressure increase within the stress segment of obstructive apnea in NR and R was investigated in a double-blind randomized study versus placebo. Data were collected in digital form with the help of cardiorespiratory polysomnography and intra-arterial blood pressure measurements; a total of 640 apnea in 16 patients were evaluated. Relevant increases in blood pressure occurred during the apnea which were, as expected, more pronounced in R (150/74 mmHg) than in NR (135/69 mmHg). The antihypertensive action of cilazapril was also stronger in R (systole--11.9/diastole--6.4 mmHg) than in NR (systolic--9.0 mmHg/diastolic--5.7 mmHg). Placebo caused significantly lower decreases in blood pressure (systolic--3.7 mmHg/diastolic--2.4 mmHg in R, systolic--2.8 mmHg/diastolic--1.8 mmHg in NR). Thus, evidence is provided for a clinically relevant blood pressure lowering effect of the drug cilazapril on the stress-induced blood pressure increases accompanying obstructive apnea both in NREM and in REM sleep.