Masking the pain; a solution for obstructive sleep apnea

This study examined the long term effects of continuous positive airway pressure on blood pressure and prognosis in hypertensive (high blood pressure) patients with coronary artery disease and obstructive sleep apnea.

Obstructive sleep apnea is a common disorder characterized by repetitive partial (hypopnea) or complete (apnea) obstruction of the upper airway during sleep, resulting in sleep fragmentation and low blood oxygen saturation.

Patients with obstructive sleep apnea frequently exhibit resistant hypertension (patients who are unable to control their high blood pressure despite the use blood pressure controlling drugs) and tend to develop coronary artery diseases (characterized by narrowing of the arteries and disrupted blood supply to the heart muscle).

Continuous positive airway pressure (CPAP) is a common treatment for obstructive sleep apnea. It’s a small machine that delivers air at a constant pressure, through a mask, to keep airways open. Previous studies have addressed the effects of CPAP on blood pressure in obstructive sleep apnea patients but have resulted in variable and conflicting outcomes. 

73 patients (45-75 years) with resistant hypertension, obstructive sleep apnea and established diagnosis of coronary artery disease (such as coronary artery constriction or history of heart attack) were randomly assigned into 2 groups. The first group (36 patients) was treated with CPAP (at least 4 hours/night) while the second group (37 patients) served as a control group (didn’t receive CPAP treatment). CPAP pressure was set to the minimum needed to abolish snoring, obstructive respiratory (lung) events and airflow limitation for the night for each patient. Both groups received conventional antihypertensive treatment (drugs to reduce high blood pressure) during the course of study. During an average follow up of 3 years blood pressure and severe cardiovascular/ cerebrovascular events (new heart attacks, heart failure, strokes) were recorded.

Following analysis researchers concluded that systolic blood pressure (pressure when the heart is contracting) was significantly lower in the CPAP treated group (139 mm Hg) compared to the control group (143 mm Hg). The average reduction in the CPAP group was 8 mm Hg compared to a reduction of 3 mm Hg in the control group. However diastolic blood pressure (pressure when the heart is relaxed) values didn’t differ between the groups.

In the CPAP group only one patient had a severe cardiovascular event compared to the control group in which 5 patients had an event.  

Furthermore the proportion of controlled hypertension (hypertension control was defined as resting blood pressure <140/90 mm Hg or <130/80 mm Hg in patients with diabetes) in the CPAP group was better than in the control group at the end of the study.

This study concluded that that long-term CPAP therapy significantly reduces systolic blood pressure and improves hypertension control in hypertensive patients with coronary artery disease and obstructive sleep apnea compared to conventional antihypertensive treatment alone.

Larger samples studies are necessary to clarify the impact of CPAP on prognosis in hypertensive patients with coronary artery disease and obstructive sleep apnea.