Repeat Revascularization After Minimally Invasive Coronary Artery Bypass Grafting: Is It a Problem?

OBJECTIVE: Minimally invasive coronary artery bypass grafting (MICS CABG) via a small left thoracotomy is a novel technique for coronary revascularization that is increasingly used around the world. However, multivessel MICS CABG is difficult, and concerns about repeat revascularization (RR) have been raised. This longitudinal study describes the rates of RR among patients who have undergone MICS CABG and identifies targets for improvement. METHODS: A prospective observational study was performed on the 306 MICS CABG patients operated on by a single surgeon from 2005 to 2015. Minimally invasive coronary artery bypass grafting was performed through a small left thoracotomy, using the in situ left internal mammary artery, ± a radial artery, and 1 to 3 saphenous veins anastomosed proximally to the aorta. Patients were followed annually. We examined the difference between the first half and second half of the series to ascertain the effects of a learning curve. RESULTS: Eighty percent of the procedures were performed off-pump. The median number of grafts performed were 2, and the left anterior descending, diagonals, obtuse marginals, and posterior interventricular artery were the distal targets in 94%, 12%, 44%, and 26%, respectively. The graftability index (#grafts/#diseased vessels) was 0.93. Revascularization of targets smaller than 1.5 mm decreased from 69% to 50% (P = 0.002) between the series' first and second halves. Overall, RR was needed in 21 patients (6.9%) and was performed at a mean ± SD of 1.7 ± 1.6 years postoperatively. The culprit lesion was attributed to the index surgical procedure ("graft-associated") in 52%, to a stent stenosis or progression of native disease in 43%, and was unidentified in 5%. Patients with graft-associated RR had a lower graftability index at operation (0.73 vs 0.94) and more frequent involvement of the circumflex system (0.8 vs 0.3). The overall rate of RR at 3 years decreased from 11% in the first half to 2.6% in the second half (P = 0.001). CONCLUSIONS: The need for RR is part of the learning curve with MICS CABG, involves a graft in half of the cases, is more common in patients who had a lower graftability index at operation, and markedly improves with experience.

Mid-Term Follow-up of Minimally Invasive Multivessel Coronary Artery Bypass Grafting: Is the Early Learning Phase Detrimental?

OBJECTIVE: Minimally invasive coronary artery bypass grafting (MICS CABG) through a small left thoracotomy is a novel technique for surgical coronary revascularization, which is increasingly being adopted around the world. This study aimed to describe the characteristics and mid-term outcomes of a series of MICS CABG to identify areas for improvement. METHODS: A prospective longitudinal study was performed on the 306 MICS CABG patients operated on by a single surgeon from 2005 to 2015. Minimally invasive coronary artery bypass grafting used a small left thoracotomy to enable coronary revascularization with a similar configuration to an open sternotomy technique, with left internal thoracic artery harvesting, and hand-sewn proximal radial/saphenous and distal anastomoses, under direct visualization. We compared patients who were operated on during the first and second halves of the series to ascertain the impact of a learning curve on outcomes. RESULTS: The mean ± SD age was 62 ± 9 years, 87% were male, and 23% had three-vessel disease. Off-pump coronary artery bypass was performed in 80%, and the median number of grafts was 2 (range 1-4). Sternotomy conversion occurred in 3.3%, reoperation for bleeding in 2%, and unplanned, emergency CPB conversion in 1%. Superficial thoracotomy infection, atrial fibrillation, and left-sided pleural effusion requiring drainage were encountered in 2%, 4%, and 4%, respectively. There were no perioperative stroke, myocardial infarction, or death. At a mean ± SD follow-up of 2.8 ± 2.5 years, 97.4% of patients were free from major adverse cardiac and cerebrovascular events. Between the first and latter half of the series, there was a decrease in the rate of conversion to sternotomy (5.2%-1.3%, P = 0.05) and in the mid-term need for repeat revascularization (11% vs 2.6%, P = 0.03). Overall repeat revascularization rate was 2.5% per year. The intensive care unit and hospital lengths of stay (1.6 ± 1.5 vs 1.4 ± 0.9, P = 0.2, and 6.1 ± 2.6 vs 5.6 ± 1.8, P = 0.4) were not statistically different. CONCLUSIONS: Minimally invasive coronary artery bypass grafting can be safely initiated as a minimally invasive, multivessel alternative to open surgical coronary revascularization, with excellent mid-term results. Learning phase effects were not observed with regard to overall procedural safety, but rather in terms of improved freedom from conversion to sternotomy and from repeat revascularization.

Predictors and Outcomes of Sternotomy Conversion and Cardiopulmonary Bypass Assistance in Minimally Invasive Coronary Artery Bypass Grafting.

OBJECTIVE: This work's objective was to identify the determinants of conversion of minimally invasive coronary artery bypass grafting to sternotomy, with and without cardiopulmonary bypass assistance, and to compare clinical outcomes in patients who needed conversion. METHODS: This is a prospectively collected data on patients who underwent minimally invasive coronary bypass done by a single surgeon from February 2005 to September 2014. Statistical analyses were expressed as mean values ± standard deviation or proportions. RESULTS: The total number of patients was 266, with an average age of 62 years. The median number of grafted territories was 2, higher in those with pump assistance (median, 3 grafts; P ≤ 0.01). Predictors for use of cardiopulmonary bypass included diabetes, 3-vessel disease, left circumflex involvement, and small target vessels (P < 0.05). The rate for sternotomy conversion was 3.8%. Risk factors for conversion to sternotomy included smoking, preoperative bradycardia (<50 beats per minute), low intraoperative ejection fraction, inability to tolerate one-lung ventilation, inadequate surgical exposure, and hemodynamic instability. Postoperative complications included superficial thoracotomy infection (3%), sternotomy infection (10%), new atrial fibrillation (3%), and need for blood transfusion (14%). Twelve patients (5%) developed left-sided pleural effusion that required drainage. There were no perioperative deaths, major adverse cardiac event, or stroke. CONCLUSIONS: Minimally invasive coronary bypass grafting with conversion to sternotomy and use of cardiopulmonary bypass is safe. Conversions may be alleviated by an effort to optimize modifiable risk factors and the adequacy of surgical exposure. These data may help develop objective selection criteria to identify patients who are excellent candidates for the procedure.