Sleep HealthCenters, a for-profit chain of sleep clinics mostly in New England, abruptly closed this week, leaving some patients who showed up for appointments facing locked doors and a closure notice citing “circumstances beyond our control.”

The Boston-based company has been struggling financially, in large part because more of the diagnostic services once provided at a sleep center are being conducted in patients’ homes, Richard Mikels, the company’s attorney, said Friday night. As a result, all 19 locations, including 11 in Massachusetts, have been closed.