(CNN) — Former US Sen. Kay Hagan of North Carolina died Monday, her family said in a statement. She was 66. “We are heartbroken to share that Kay left us unexpectedly this morning,” the Hagan family said. “Kay meant everything to us, and we were honored to share her with the people of North Carolina whom she cared for and fought for so passionately as an elected official. “The family did not provide information on the cause of death. Hagan, a Democrat, served in the Senate from 2009 to 2015. She lost her reelection bid in November 2014 to Republican Sen. Thom Tillis.