Impact of obstructive sleep apnea on blood pressure in patients with hypertension

Barry Fields¹, Indira Gurubhagavatula^1–3
1Division of Sleep Medicine, Perelman School of Medicine, University of Pennsylvania, ²Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of Pennsylvania, ³Philadelphia VA Medical Center, Philadelphia, Pennsylvania, USA

Abstract: Hypertension is the most significant risk factor for death worldwide. Approximately 30%–40% of affected individuals have coexisting obstructive sleep apnea (OSA), a disorder resulting from the upper airway’s inability to remain patent during sleep. A causal relationship between OSA and hypertension has been demonstrated. Blunting or elimination of normal blood pressure (BP) dipping during sleep is commonly seen in OSA patients, with corresponding increases in daytime BP. This dipping is clinically salient, because it is associated with the end-organ damage seen with chronic hypertension, such as cardiovascular, renal, and cerebrovascular disease. African-Americans are at greatest risk for non-dipping and end-organ damage. Rapidly fluctuating changes in sympathetic tone, intrathoracic pressure, oxyhemoglobin saturation, and carbon dioxide levels are all thought to play a role in acute and chronic BP elevation. Individuals with preexisting hypertension are most susceptible to OSA’s BP-raising effects. First-line therapy for OSA includes continuous positive airway pressure (CPAP) delivered via a mask interface. Patients who show the greatest BP declines while using CPAP are more likely to be those who have at least moderate OSA, adhere to therapy, have preexisting hypertension, and whose blood vessels retain reversibility in disease-related remodeling. Given the heavy burden OSA-related hypertension places on the healthcare system, prevention, early detection, and prompt intervention should be the goals for all affected individuals.

Keywords: obstructive sleep apnea (OSA), hypertension, nocturnal dipping, continuous positive airway pressure (CPAP)