Hemodynamic Changes during off Pump Coronary Artery Bypass Surgery

Han, Sung Hee; Kim, Jin Hee; Sim, Sung Eun; Ham, Byung Moon

Abstract

BACKGROUND: The number of coronary artery bypass graft surgery without cardiopulmonary bypass is increasing in Korea. This technique avoids a number of the adverse effects associated with cardiopulmonary bypass. But the cardiac exposure and stabilization during off pump coronary artery bypass graft surgery (OPCAB) are known to cause hemodynamic deterioration and it creates new challenges for the anesthesiologist. This study is designed to assess the hemodynamic changes during OPCAB.
METHODS
Eighteen patients undergoing OPCAB were included in this study (male/female = 13/5, age = 63.5+/-5.2). An octopus(R), a local cardiac-wall restraining device was applied for stabilization of target coronary artery. Three different surgical settings of exposure and stabilization were used according to the site of anastomosis: left anterior descending artery (LAD), posterior descending artery (PDA) and circumflex branch of left coronary artery (LCx). Heart rate (HR), mean systemic arterial pressure (MAP), central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP) and cardiac output (CO) were measured. CO was measured with thermodilution technique. Stroke volume index (SVI) and cardiac index (CI) were calculated. On each of the surgical settings, hemodynamic parameters were measured at 5 minutes before exposure of target coronary artery, and 5 minutes after placement of the stabilizer and 5 minutes after the completion of anastomosis.
RESULTS
During LAD anastomosis, SVI decreased slightly (7.8%), but MAP and CI remained unchanged. During PDA and LCx anatomosis, MAP decreased moderately (15.7% and 16.1%, respectively) and SVI decreased remarkably (24.9% and 32.9%). Also CI did decrease, but it was less remarkable compared to the decrease in SVI due to the increase of HR. CVP and PCWP increased during PDA and Cx anastomosis. When the heart was released, all of the hemodynamic parameters were restored to baseline values.
CONCLUSIONS
Hemodynamic changes during OPCAB were remarkable, especially with PDA and LCx reconstruction. However, these changes were transient and they were well tolerated in most patients.