OSA Has Genetic Links

By Robert Preidt

 

Friday, September 1, 2006

(HealthDay News) - Mayo Clinic researchers say they've identified a new type of sleep apnea called "complex sleep apnea" that may be resistant to standard treatment such as continuous positive airway pressure (CPAP).

 

"All of us in our sleep lab have observed for years that there are patients who appear to have obstructive sleep apnea, but the CPAP doesn't make them all that much better -- they still have moderate to severe sleep apnea even with our best treatment and subjectively don't feel they're doing very well," study lead investigator Dr. Timothy Morgenthaler, a sleep medicine specialist and pulmonologist, said in a prepared statement.

 

Until now, obstructive sleep apnea and central sleep apnea have been the two known types of apnea. Obstructive sleep apnea, which is most common, occurs when the throat muscles relax and the airway narrows, which momentarily cuts off breathing and causes loud snoring. In central sleep apnea, the brain fails to send the proper signals to the muscles that control breathing.

 

Complex sleep apnea is a combination of both obstructive and central sleep apnea, according to the Mayo researchers. Their findings were published in the September issue of the journal Sleep.

 

The study of 223 patients referred to the Mayo Clinic Sleep Disorder Center found that 15 percent of the patients had complex sleep apnea, 84 percent had obstructive sleep apnea and 0.4 percent had central sleep apnea. Males are more likely to have complex sleep apnea.

 

At first, patients with complex sleep apnea appear to have obstructive sleep apnea and stop breathing 20 to 30 times per hour each night. However, unlike people with typical obstructive sleep apnea, the breathing problems in patients with complex sleep apnea aren't completely relieved by a CPAP machine, which keeps a patient's airway open during sleep.

 

"When they put on a CPAP machine, they start to look like central sleep apnea syndrome patients. This phenomenon has been observed for years, but this study is the first to attempt to categorize these people," he said.

 

There are no known risk factors for complex sleep apnea, and an effective treatment for the condition has not yet been identified, Morgenthaler said.

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