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.

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.

Impact of subglottic suctioning on the incidence of pneumonia after cardiac surgery: a retrospective observational study.

OBJECTIVE: Continuous aspiration of subglottic secretions (CASS) has been found to decrease the incidence of pneumonia in the general intensive care unit (ICU) population, but its benefit in cardiac surgery patients is unclear. The present study aimed to determine whether the routine use of CASS in cardiac surgical patients was associated with decreased pneumonia. DESIGN: A retrospective, single-center observational study. SETTING: The study was conducted in a quaternary care cardiac surgery center and university research hospital. PARTICIPANTS: 4,880 patients undergoing cardiac surgery were studied. INTERVENTIONS: The control group (no CASS) received a standard endotracheal tube and underwent surgery between April 1, 2007 and March 31, 2009. The intervention group (CASS) received a subglottic suctioning endotracheal tube and underwent surgery between June 1, 2009 and May 31, 2011. The primary outcome was the development of pneumonia, and the secondary outcomes were 30-day in-hospital mortality, ventilation time, need for tracheostomy, ICU length of stay (LOS), and hospital LOS. MEASUREMENTS AND MAIN RESULTS: The unadjusted incidence of pneumonia was 1.9% in the CASS group and 5.6% in the control group (p<0.0001). The CASS group also had lower 30-day in-hospital mortality (2.1% v 3.3%; p = 0.007), median ventilation time (8.42 v 7.3 hours; p<0.0001), and shorter median ICU LOS (1.77 v 1.17 days; p<0.0004) compared with the control group. Tracheostomy rates and median hospital LOS did not differ between groups. After adjusting using multivariable modeling, CASS remained an independent risk predictor for pneumonia (odds ratio [OR] 0.342, 95% confidence interval [CI] 0.239-0.490) and ICU LOS (OR 0.817, 95% CI 0.718-0.931). CONCLUSIONS: The universal implementation of CASS in a quaternary care cardiac surgical population was associated with a decreased incidence of pneumonia.

Delayed thrombin generation with hirudin anticoagulation during prolonged cardiopulmonary bypass.

Patients with heparin-induced thrombocytopenia requiring urgent cardiac surgery present a unique challenge that must be addressed by the use of nonheparin alternatives for anticoagulation during cardiopulmonary bypass. Although isolated cases have been presented involving the use of antithrombin III independent thrombin inhibitor hirudin in this situation, its ability to completely inhibit thrombin activity has not been demonstrated. In this report we describe the efficacy of this drug in inhibiting thrombin during a case requiring prolonged cardiopulmonary bypass.

Endogenous myocardial angiogenesis and revascularization using a gastric submucosal patch.

BACKGROUND: The gastrointestinal submucosa physiologically produces angiogenic proteins. We examined whether these properties could lead to endogenous myocardial angiogenesis in a swine model of chronic ischemia. METHODS: Fifteen Yorkshire swine underwent ameroid constrictor placement around the circumflex artery and either lateral epicardial abrasion, creation of a gastroepiploic artery (GEA) based gastric patch, mucosal avulsion, transdiaphragmatic transfer, and apposition of the patch against the circumflex myocardial territory (number = 8; test animals), or lateral epicardial abrasion alone (number = 7; controls). Seven weeks later, lateral myocardial perfusion, endothelial cell density, and expression of VEGFR-1 and VE-cadherin were determined using isotope-labeled microsphere assays, immunohistochemistry, and immunoblotting, respectively. RESULTS: Microsphere assays showed equivalent lateral/anterior myocardial perfusion indices at rest (1.10 +/- 0.49 vs 0.95 +/- 0.23, test vs control animals; p = 0.54), but higher perfusion in test animals versus controls during pacing (1.05 +/- 0.29 vs 0.69 +/- 0.09, test vs controls; p = 0.02). Increased myocardial endothelial cell density (42.6 +/- 8.5 vs 26.1 +/- 11.6 cells per 3850 microm2, test vs controls; p = 0.02) and expression of VE-cadherin (3.10 +/- 0.60-fold change, test vs controls; p = 0.001) were also observed in the lateral territory of test animals versus controls. Reconstitution of the proximally occluded circumflex artery from patch collaterals was demonstrated on gastroepiploic arteriography in a subset of test animals. CONCLUSIONS: This model results in an angiogenic process of significantly greater magnitude than that resulting from chronic myocardial ischemia alone, without the need for exogenous angiogenic agents.