Losartan prevented the increase in resting mean arterial pressure induced by 6 hours of intermittent hypoxia compared to placebo (-0.2 vs 7.9 mm Hg; P<0.05).
RCT (n=9)
Double-blind
Crossover
Does losartan prevent the increase in arterial blood pressure induced by intermittent hypoxia in healthy male subjects?
Losartan prevents the acute increase in blood pressure caused by intermittent hypoxia, demonstrating that this hypertensive response is dependent on the renin-angiotensin system.
Absolute Event Rate: -0.2% vs 7.9%
p-value: p=<0.05
Intermittent hypoxia (IH) is believed to contribute to the pathogenesis of hypertension in obstructive sleep apnea through mechanisms that include activation of the renin-angiotensin system. The objective of this study was to assess the role of the type I angiotensin II receptor in mediating an increase in arterial pressure associated with a single 6-hour IH exposure. Using a double-blind, placebo-controlled, randomized, crossover study design, we exposed 9 healthy male subjects to sham IH, IH with placebo medication, and IH with the type I angiotensin II receptor antagonist losartan. We measured blood pressure, cerebral blood flow, and ventilation at baseline and after exposure to 6 hours of IH. An acute isocapnic hypoxia experimental protocol was conducted immediately before and after exposure to IH. IH with placebo increased resting mean arterial pressure by 7.9+/-1.6 mm Hg, but mean arterial pressure did not increase with sham IH (1.9+/-1.5 mm Hg) or with losartan IH (-0.2+/-2.4 mm Hg; P<0.05). Exposure to IH prevented the diurnal decrease in the cerebral blood flow response to hypoxia, independently of the renin-angiotensin system. Finally, in contrast to other models of IH, the acute hypoxic ventilatory response did not change throughout the protocol. IH increases arterial blood pressure through activation of the type I angiotensin II receptor, without a demonstrable impact on the cerebrovascular or ventilatory response to acute hypoxia.
Foster et al. (Tue,) conducted a rct in Healthy subjects (n=9). Intermittent hypoxia with losartan vs. Intermittent hypoxia with placebo and sham intermittent hypoxia was evaluated on Change in resting mean arterial pressure (p=<0.05). Losartan prevented the increase in resting mean arterial pressure induced by 6 hours of intermittent hypoxia compared to placebo (-0.2 vs 7.9 mm Hg; P<0.05).