Nationally, less than 20% of all bypass surgeries are performed off pump. At Stamford Hospital's Heart and Vascular Institute almost 100% of bypass surgeries are performed off pump. 
Off-Pump Bypass Surgery
Coronary artery bypass surgery uses vessels (artery and vein) harvested from elsewhere in your body to bypass blockages in the arteries supplying blood to your heart.
Traditionally, coronary artery bypass surgery is performed with the assistance of a heart-lung machine that allows the heart's beating to be stopped, so that the surgeon can operate on a surface which is blood-free and still.
Off-pump coronary artery bypass surgery differs from traditional coronary artery bypass surgery, because the heart-lung machine is not used. The advantages of "beating heart" off-pump surgery are many and include shorter operative time, less manipulation of the patient's aorta, and less trauma to the heart. Additionally, using this technique requires less anticoagulation during surgery, better preservation of the patient's platelets and less post-operative bleeding.
