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Background: The Arterial Revascularization Trial has been designed to answer the question whether the use of bilateral internal thoracic arteries can improve 10-year outcomes when compared with single internal thoracic arteries. In the Arterial Revascularization Trial, a significant proportion of patients initially allocated to bilateral internal thoracic arteries received other conduit strategies. We sought to investigate the incidence and clinical implication of bilateral internal thoracic artery graft conversion in the Arterial Revascularization Trial., Methods: Among patients enrolled in the Arterial Revascularization Trial (n = 3102), we excluded those allocated to single internal thoracic arteries (n = 1554), those who did not undergo surgery (n = 16), and those who underwent operation but withdrew after randomization (n = 7). Propensity score matching was used to compare converted versus nonconverted bilateral internal thoracic artery groups., Results: A total of 1525 patients were operated with the intention to receive bilateral internal thoracic artery grafting. Of those, 233 (15.3%) were converted to other conduit selection strategies. Incidence of conversion largely varied across 131 participating surgeons (from 0% to 100%). The most common reason for bilateral internal thoracic artery graft conversion was the evidence of at least 1 internal thoracic artery that was not suitable, which was reported in 77 cases. Patients with intraoperative bilateral internal thoracic artery graft conversion received a lower number of grafts (2.95 ± 0.84 vs 3.21 ± 0.74; P < .001). However, the hospital mortality rate was comparable to that of those who did not require bilateral internal thoracic artery graft conversion (0% vs 1.6%; P = .1), as well as the incidence of major complications. At 5 years, we found a nonsignificant excess of deaths (11.9% vs 8.4%; P = .1) and major adverse events (17.1% 13.2%; P = .1) mainly driven by an excess of revascularization in patients requiring conversion., Conclusions: The incidence of intraoperative bilateral internal thoracic artery graft conversion is not infrequent. Bilateral internal thoracic artery graft conversion is not associated with increased operative morbidity, but its effect on late outcomes remains uncertain., (Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: We sought to identify the trends in bilateral internal thoracic artery use and determine the degree to which the survival advantage of bilateral internal thoracic artery revascularization persists among perceived "high-risk" patients, compared with the use of left internal thoracic artery alone., Methods: A retrospective review was conducted of patients who underwent isolated coronary artery bypass grafting for multivessel coronary artery disease at the Mayo Clinic between January 2000 and December 2015. Propensity score matching was performed between patients with bilateral internal thoracic artery and left internal thoracic artery alone grafts (1011 matched pairs). Effect of bilateral internal thoracic artery use on survival in "high-risk" patients (ejection fraction <40%, body mass index ≥30, age ≥70 years, diabetes, chronic lung disease, cerebrovascular accident) was evaluated., Results: A total of 6468 isolated coronary artery bypass grafts were performed (5431 using left internal thoracic artery alone, 1037 using bilateral internal thoracic artery). There was an increasing trend in bilateral internal thoracic artery use (P value for linear trend = .005), with the percentage of coronary artery bypass grafting cases with bilateral internal thoracic artery doubling over the last 4 years (13% in 2012 to 27% in 2015). Propensity-matched comparisons showed a survival advantage for bilateral internal thoracic artery (hazard ratio, 0.81; 95% confidence interval, 0.66-0.99; P = .043). Risk of deep sternal wound infection, although higher in the bilateral internal thoracic artery group, was not significant (1.2% vs 0.5%; P = .088). None of the "high-risk" subsets of patients showed an adverse effect of bilateral internal thoracic artery on survival., Conclusions: Bilateral internal thoracic artery use in coronary artery bypass grafting is increasing over time. There is a consistent survival benefit with bilateral internal thoracic artery use, extending to patients with higher-risk comorbidities, suggesting the need for further expansion in use of this technique., (Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: The goal of this study was to characterize the adoption rate and regional variation in bilateral internal mammary artery (BIMA) use during coronary artery bypass grafting (CABG) in the United States., Methods: Observational study of 100% sample of fee-for-service Medicare beneficiaries aged 65 years or older, continuously enrolled in Parts A and B from 2009 to 2014 (n = 162,860,439). Rates of beneficiaries receiving a BIMA versus single internal mammary artery (SIMA) during CABG are expressed per 1,000 beneficiaries and aggregated by Hospital Referral Region (HRR). An HRR is a validated unit for quantifying regional variation in health care., Results: The absolute national rate of BIMA use declined during the study period from 0.21 claims per 1,000 beneficiaries in 2009 to 0.13 in 2014 (p < 0.001). When indexed to overall CABG volume, no change was seen in the frequency of BIMA use over time (p = 0.883). SIMA use ranged from 1.3 to 8.5 claims per 1,000 Medicare beneficiaries, whereas BIMA use ranged from 0 to 1.5 (p < 0.001). A significant correlation was found between regional volume of SIMA use and likelihood of BIMA use (correlation coefficient 0.673, p < 0.001). Although both SIMA and BIMA use correlated with regional volume of diagnostic cardiac catheterization, the correlation was stronger for SIMA use (correlation coefficient 0.962 versus 0.682, p < 0.001)., Conclusions: Over the past 5 years, no growth was seen in BIMA use among Medicare beneficiaries, and the frequency of BIMA use during CABG remained low. There was significant regional variation in BIMA use, however, which demonstrates opportunity for continued growth of BIMA grafting., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: The internal mammary artery (IMA) is the preferred conduit for bypassing the left anterior descending (LAD) artery in patients undergoing coronary artery bypass grafting. Systematic evaluation of the frequency and predictors of IMA failure and long-term outcomes is lacking., Methods and Results: The Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV trial participants who underwent IMA-LAD revascularization and had 12- to 18-month angiographic follow-up (n=1539) were included. Logistic regression with fast false selection rate methods was used to identify characteristics associated with IMA failure (≥75% stenosis). The relationship between IMA failure and long-term outcomes, including death, myocardial infarction, and repeat revascularization, was assessed with Cox regression. IMA failure occurred in 132 participants (8.6%). Predictors of IMA graft failure were LAD stenosis <75% (odds ratio, 1.76; 95% confidence interval, 1.19-2.59), additional bypass graft to diagonal branch (odds ratio, 1.92; 95% confidence interval, 1.33-2.76), and not having diabetes mellitus (odds ratio, 1.82; 95% confidence interval, 1.20-2.78). LAD stenosis and additional diagonal graft remained predictive of IMA failure in an alternative model that included angiographic failure or death before angiography as the outcome. IMA failure was associated with a significantly higher incidence of subsequent acute (<14 days of angiography) clinical events, mostly as a result of a higher rate of repeat revascularization., Conclusions: IMA failure was common and associated with higher rates of repeat revascularization, and patients with intermediate LAD stenosis or with an additional bypass graft to the diagonal branch had increased risk for IMA failure. These findings raise concerns about competitive flow and the benefit of coronary artery bypass grafting in intermediate LAD stenosis without functional evidence of ischemia., Clinical Trial Registration: URL: http:/www.clinicaltrials.gov. Unique identifier: NCT00042081., (© 2015 American Heart Association, Inc.)