Echocardiographic findings in minimally invasive coronary artery bypass grafting: The role of intrathoracic CO2 - insufflation and single lung ventilation.

Background: Current options for surgical treatment of coronary single vessel disease range from beating heart procedure without cardiopulmonary bypass via a mini thoracotomy (MIDCAB) to totally endoscopic robot-assisted techniques (TECAB) with cardiopulmonary bypass. Both procedures are associated with considerable stress even before revascularization such as single lung ventilation, temporary coronary occlusion, Luxatio cordis, intrathoracic CO2 insufflation and extended bypass and operating time. The aim of the this study was to document the extent of intraoperative segmental wall motion abnormalities (SWMA) by echocardiography, and to identify variables affecting SWMA.

Materials And Methods: Forty patients with coronary single vessel disease were included in the study. 16 patients were operated with the MIDCAB technique, and 24 patients underwent TECAB. In both groups of patients sequential transesophageal echocardiograms (2D-loops) were recorded and analyzed. Hemodynamic and electrocardiographic data as well as oxygenation parameters were acquired during echo exams. In both groups of patients mild, but significant perioperative SWMA were identified, which increased in the course of the operation. These SWMA were more pronounced in the TECAB as compared to the MIDCAB group. Independent of operating time these changes disappeared completely until the ends of surgery. Significant hemodynamic or elektrocardiographic modifications were not observed.

Conclusion: The application of minimally invasive techniques for the surgical treatment of coronary single vessel disease is associated with significant perioperative SWMA. The more pronounced SWMA in the TECAB group may be a consequence of intrathoracic CO2-insufflation. Both techniques can be applied without significant myocardial ischemia, provided that appropriate intraoperative monitoring is performed, and intrathoracic CO2 pressure in TECAB patients is limited.