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OBJECTIVE: Robotic-assisted coronary artery bypass is a minimally-invasive alternative to traditional coronary artery bypass surgery (CABG) via median sternotomy. However, this minimally-invasive, sternal-sparing technique is associated with a learning curve. The purpose of this study was to investigate the reasons for conversion to sternotomy and to determine if the conversion rate varied with surgeon experience.
METHODS: From 10/09 to 12/11, 213 consecutive robotic-assisted CABG procedures were performed at US academic institution by two surgeons. In all cases, isolated, off-pump, left internal mammary artery (LIMA) to left anterior descending coronary artery (LAD) grafting was planned via a 3-4 cm sternal-sparing thoracotomy after robotic LIMA harvest and pericardiotomy.
RESULTS: Conversion to sternotomy occurred in 14/213 (6.6%) patients. The most common reason for conversion was technical difficulty with the LIMA-LAD anastomosis, which occurred in 6/14 (42.9%) patients. Other reasons included the following: LIMA dissection, 2 (14.3%); wrong vessel grafted 2 (14.3%); ventricular fibrillation and cardiac arrest, 1 (7.1%); right ventricular injury during port placement, 1 (7.1%); technical problems with robotic system, 1 (7.1%); and left chest adhesions, 1 (7.1%). Two patients underwent emergent conversion. Three patients underwent conversion based on results of intraoperative completion angiography. Six patients were planned hybrid coronary revascularization procedures and underwent multivessel CABG after conversion. There was no mortality among patients that required conversion to sternotomy. However, 2 patients had postoperative myocardial infarction and 1 had a superficial sternal wound infection. The conversion rate was not significantly different among the 4 different time quartiles of the study (Figure).
CONCLUSIONS: Conversion to sternotomy is a relatively infrequent complication of robotic-assisted CABG, most commonly due to technical difficulties during the LIMA-LAD anastomosis. Conversions should be expected in a portion of these procedures due to anatomic and patient variables as well as inherent technical problems with minimally-invasive procedures. Based on these data, conversion may be more related to anatomic and patient-specific variables than surgeon experience.