Systemic capillary leak syndrome is defined as excessive fluid and protein extravasation caused by microvascular hyperpermeability. It is a very rare condition, and may occur during or after any surgery without preceding symptoms or a suggestive history. It has been reported in pediatric cardiac surgery patients, and is not expected in adults.

In this article, we present a 75-year-old female case of severe systemic capillary leak developed during coronary artery bypass grafting combined with dual valve replacement. To the best of our knowledge, this is the first adult case in the literature having an acute attack of systemic capillary leak syndrome during cardiac surgery.