Off-Pump Bypass Safe for High-Risk Patients

Patients at high risk for complications after heart surgery may benefit from off-pump surgery, according to a study reported at the annual Clinical Congress of the American College of Surgeons (ACS) in New Orleans (LA, USA) in October 2004.

The standard on-pump procedure, which allows surgeons to operate on the heart at rest while blood pumps through a heart-lung machine, generates a systemic inflammatory response because the patient's blood comes in contact with artificial surfaces. This may cause lung insufficiency, bleeding, kidney insufficiency, or stroke in high-risk patients. The on-pump procedure also minimizes pulsatile blood flow. The absence of normal heart movement is correlated with a high incidence of renal failure in patients with renal insufficiency. In addition, because the on-pump operation requires the aorta to be clamped, it can further compromise a calcified aorta.

Since 2000, Dr. John C. Chen, M.D., and his surgical team have performed 191 off-pump artery bypass operations on high-risk patients. For 97 patients who underwent the procedure in 2002, the expected mortality was 7.68%, but the observed mortality was only 4.17%. In 2003, the outcome was even better. The expected mortality for 54 patients in off-pump procedures was 7.85%, while the observed mortality was only 1.85%.

Among new tools that have improved the surgery is an apical suction device placed on the apex of the heart to hold it steady during surgery and a new stabilizing device that is placed on the coronary artery to hold it relatively steady. "The artery is not completely still, but it is still enough so experienced surgeons can do an anastomosis with good results,” reported Dr. Chen, who is a professor at the University of Hawaii and chief of cardiothoracic surgery at Kaiser Permanente, Honolulu (Hawaii, USA). Dr. Chen reported the study's findings.