Can CPAP Treat Hypertension in Sleep Apnoea Patients?

CPAP or continuous positive airway pressure is said to be the standard treatment for sleep apnoea, a condition wherein there is cessation of breathing and reduction of ventilation during sleep. This device uses mild air pressure to keep the airways open. It may also be used to treat preterm infants whose lungs have not fully developed, as in infants who have respiratory distress syndrome or bronchopulmonary dysplasia.

One of the complications of sleep apnoea is hypertension. Hypertension in turn causes other hazards to health such as artery damage and narrowing, aneurysm, coronary artery disease, heart enlargement, heart failure, stroke, dementia, kidney failure, eye and nerve damage, sexual dysfunction and many other problems. This is why hypertension needs to be controlled as soon as possible among sleep apnoea patients. It is said that the incidence of resistant hypertension is particularly high in OSA patients, in spite of the use of three or more antihypertensive drugs.

However, there are reports which say that continuous positive airway pressure (CPAP) therapy can exert a hypotensive effect on OSA patients with resistant hypertension. A recent Japanese study has reported about the hypotensive effects of CPAP therapy in Japanese OSA patients with resistant hypertension.

These patients exhibited uncontrolled blood pressure (BP; clinic BP 140/90 mmHg) despite receiving treatment with three or four antihypertensive drugs. All risk factors for secondary hypertension, except for OSA, were ruled out based on the findings of ultrasonography, magnetic resonance imaging (MRI), computed tomography (CT) and blood sampling. The presence of OSA was determined using full polysomnography (PSG). Noninvasive ambulatory BP monitoring (ABPM) was performed for 24 hours. Each patient recorded when they fell asleep at night and woke in the morning on the ABPM.

In the first case, a 58-year-old woman exhibited a decreased 24-hour BP and changes in the nocturnal BP dipping pattern from non-dipper to dipper. In the second case, a 64-year-old man showed no improvements in nocturnal BP, while in the third case, a 78-year-old man with ischemic cardiomyopathy exhibited changes in the nocturnal BP dipping pattern from non-dipper to dipper. These results suggest that 6-month CPAP therapy improves the nocturnal BP dipping status in some patients with obstructive sleep apnoea and resistant hypertension.

The findings were compatible with previous reports that recommended CPAP therapy in sleep apnoea patients with resistant hypertension. Kario recommended the use of CPAP therapy in OSA patients with an AHI of 20/hour complicated by hypertension. Bazzano et al. reviewed 255 reports of 16 randomised clinical trials and concluded that 2-week CPAP therapy decreases the BP values in OSA patients. Akashiba et al. reported that 3-day CPAP therapy reduces diurnal and nocturnal BP and results in changes from a “non-dipper” to a “dipper” status in OSA patients. Lozano et al. demonstrated that, in their study, 3-month CPAP treatment achieved reductions in 24-hour systolic BP (-9.71 mmHg), 24-hour diastolic BP (-6.98 mmHg), and daytime diastolic BP (-6.12 mmHg) in OSA patients with ABPM-confirmed resistant hypertension.

Further studies are needed to verify the effects of CPAP therapy on patients with resistant hypertension on a larger scale.

Reference:

Sekizuka H, Osada N, Miyake F. Effects of continuous positive airway pressure therapy in three Japanese patients with obstructive sleep apnoea and resistant hypertension. Intern Med. 2013;52(19):2241-4.

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