People who have severe obstructive sleep apnoea may be more likely to experience cardiovascular problems after major noncardiac surgery, a study suggests.

Compared with patients without apnoea, those with severe apnoea were more than twice as likely to die of heart complications or experience events such as myocardial infarction and stroke within 30 days of the operation, researchers report.

The researchers performed sleep studies on 1218 patients in five countries before they had surgery, finding two-thirds had unrecognised sleep apnoea.

Slightly more than one in 10 patients in the study had severe apnoea, when breathing stopped and started more than 30 times a night.