WEDNESDAY, June 15, 2016 (HealthDay News) -- Sleep apnea may increase the risk of serious complications in people who have undergone angioplasty to clear blocked heart arteries, researchers say.

In angioplasty, also called percutaneous coronary intervention (PCI), blocked heart arteries are re-opened using a thin catheter inserted through the groin or wrist.

The new study included 241 patients who underwent angioplasty. Their average age was 64 years, and the patients were followed for about six years.

Of those patients, slightly more than half had sleep-disordered breathing, which includes sleep apnea and snoring. Sleep apnea is a common and chronic condition, according to the U.S. National Heart, Lung, and Blood Institute (NHLBI). In sleep apnea, breathing stops or becomes shallow during sleep. Breathing pauses can last from a few seconds to minutes, the NHLBI says.

Sleep-disordered breathing was detected through heart and respiratory monitors used overnight after the procedure, the researchers said.

During the follow-up, 21 percent of patients with sleep-disordered breathing had major heart events, including heart attack, stroke and heart failure. In people who didnt have sleep-disordered breathing troubles, the heart complication rate was just 8 percent, the study found.

People with sleep-disordered breathing were also more likely to die during the follow-up, the findings showed. However, the study can only show an association between these factors, not a direct cause-and effect link.

The findings were published online June 15 in the Journal of the American Heart Association.

"Sleep-disordered breathing, which includes snoring and sleep apnea, has long been recognized as an important risk factor for heart disease," study author Dr. Toru Mazaki said in a journal news release.

"However, there is limited awareness of sleep-disordered breathing among cardiologists who care for PCI patients," said Mazaki, who is chief physician in the department of cardiology at Kobe Central Hospital in Japan.

Mazaki said the study results suggest that sleep-disordered breathing problems are an important risk factor for stroke, heart failure and more after angioplasty.

"Doctors and patients should consider sleep studies [after an angioplasty] to rule out sleep-disordered breathing or take necessary precautions to restore healthy breathing during sleep," Mazaki said.

The standard treatment for sleep apnea is continuous positive airway pressure, or CPAP. A CPAP mask pushes air into the persons airways while asleep. Additional options include dental devices and surgery.