The parent of 229-bed Winchester Hospital said Friday it has struck a formal affiliation agreement to become part of Lahey Health, which operates Lahey Hospital & Medical Center in Burlington, Beverly Hospital, and Addison Gilbert Hospital in Gloucester.
Lahey Health and Winchester Healthcare Management signed a letter of intent in June to affiliate. The formal agreement disclosed Friday is subject to state and federal regulatory approval. The parties said Winchester Hospital patients would maintain access to their hospital-affiliated doctors but be referred to Lahey specialists for more complex clinical procedures. Full story for BostonGlobe.com subscribers.