 -- Actor Bill Paxton died of stroke days after undergoing surgery to fix an aortic aneurysm and repair a heart defect, according to his death certificate.

The 61-year-old actor died on February 25, just 11 days after undergoing surgery to repair the aneurysm and replace a valve in his heart.

His death certificate also revealed that the longtime actor, star of films like "Twister" and "Aliens," was born with a form of heart disease called bicuspid aortic valve. It is a birth defect characterized by the aortic valve having only two small leaflets that help regulate blood flow in the heart instead of the usual three.

The defect is associated with increased risk of aneurysm, stroke or heart failure. It is one of the most common cardiac birth defects and is estimated to be present in 2 percent of the population, according to the Cleveland Clinic.

At least a third of people with the defect will develop a complication during their lifetime, according to multiple published medical studies. Paxton's death certificate does not specify the cause of his fatal stroke or whether it was related to his birth defect.

Paxton's representative did not immediately respond to ABC News' request for additional comment about the cause of death. In an earlier statement, his family said the actor and Texas native died due to complications from surgery.

"It is with heavy hearts we share the news that Bill Paxton has passed away due to complications from surgery," the statement said. "A loving husband and father, Bill began his career in Hollywood working on films in the art department and went on to have an illustrious career spanning four decades as a beloved and prolific actor and filmmaker. Bill's passion for the arts was felt by all who knew him, and his warmth and tireless energy were undeniable. We ask to please respect the family's wish for privacy as they mourn the loss of their adored husband and father."