Background
Obstructive sleep apnoea (OSA) is a common sleep disorder in which the upper airway repeatedly collapses during sleep, causing breathing pauses, fragmented sleep, and drops in blood oxygen levels. These repeated events place strain on the heart and blood vessels. OSA is strongly linked with hypertension, coronary artery disease, stroke, heart failure, and other cardiovascular problems.
Continuous positive airway pressure, or CPAP, is the standard treatment for moderate to severe OSA. It works by delivering a steady stream of air through a mask to keep the airway open during sleep. CPAP improves breathing and sleep quality, but large randomized trials in patients with cardiovascular disease have generally not shown a clear reduction in major cardiovascular events overall. That has raised an important question: could CPAP help some patients more than others?
