Stroke and Obstructive Sleep Apnea

How does stroke relate to sleep apnea?

Sleep apnea increases the chance of having a stroke.

Yaggi and others (New Eng J Med 2005;353:2034) evaluated the risk for stroke or death from any cause in relation to the presence of sleep apnea. They studied 1,022 patients (68% of whom had sleep apnea) age 50 or greater. The patients with sleep apnea had an average apnea-hypopnea index (AHI) of 35/hr (indicating severe sleep apnea) compared to the control group which had a normal AHI of 2/hr. The majority of patients received some type of treatment for sleep apnea (58% used CPAP effectively).

When adjustment for other medical conditions, the sleep apnea group had a 2.24 times increased risk of stroke or death from any cause over an average follow up of 3.4 years. Worsening severity of sleep apnea was related to even higher risk The group with the lowest AHI (4-12/hr) had a 1.75 times increased risk and those with an AHI > 36/hr who had a 3.3 times increased risk.

How does treatment with CPAP affect risk for stroke?

We do not have good data regarding stroke risk in people who do not have vascular disease. However, people who have already had a stroke (a high risk group) are at increased risk if they do not use CPAP.

Martinez-Garcia (Chest 2005;128:2123) studied patients who had a stroke and performed sleep studies at least 2 months after the stroke. 51 patients were found to have sleep apnea with at least an AHI of 20/hr (moderate to severe sleep apnea). All patients were offered CPAP therapy, but only 30% tolerated the treatment (which is a low percentage).

The patients were followed for 18 months for new vascular events (stroke or heart attack). The patients who used CPAP had a 6.7% chance of a new vascular event while the group that did not tolerate CPAP had a 36.1% chance of having a new vascular event!