Guidance for the use of bilateral internal thoracic arteries according to survival benefit across age groups Umberto Benedetto, MD, PhD, Mohamed Amrani, MD, PhD, FETCS, FRCS, and Shahzad G. Raja, MRCS, FRCS(C-Th), on behalf of the Harefield Cardiac Outcomes Research Group Objective: Increasing evidence from observational cohort studies supports a survival advantage from bilateral internal thoracic artery (BITA) relative to single internal thoracic artery (SITA) grafts in patients undergoing coronary artery bypass grafting. Whether the survival benefit from BITA is related to patient age and any potential age cutoff for the loss of survival benefit from BITA remain to be determined. Methods: Flexible parametric spline survival model was used to investigate the survival benefit from BITA across patient age groups. The study population consisted of 4190 patients undergoing coronary artery bypass grafting with SITA (n ¼ 3442; 81%) or BITA (n ¼ 748; 19%). Results: A total of 376 deaths (BITA, n ¼ 29; SITA, n ¼ 347) were recorded after a mean follow-up of 4.9  3.2 years (maximum, 12.2 years). Nonparametric survival probabilities at 1-, 5-, and 10-year follow-ups were 94.9%  0.3% versus 98.0%  0.5%, 90.7%  0.5% versus 95.5%  0.9%, and 84.2%  1.0% versus 93.7%  1.4% in the SITA and BITA groups, respectively. Interaction between age and BITA (age*BITA) was found to affect survival significantly (coefficient, 0.056; SE, 0.02; P ¼ .015). BITA was associated with reduced risk of mortality in patients aged 69 years and younger (fully adjusted hazard ratio, 0.49; 95% confidence interval, 0.24-0.98; P ¼ .04). On the other hand, for patients aged older than 69 years, BITA did not add any significant survival advantage (adjusted hazard ratio, 1.27; 95% confidence interval, 0.75-2.14; P ¼ .37). Conclusions: This study provides robust scientific evidence for the loss of survival benefit from BITA for patients older than 69 years. (J Thorac Cardiovasc Surg 2014;148:2706-11) The use of single left internal thoracic artery (SITA) to the left anterior descending artery and saphenous vein grafts (SVGs) for non–left anterior descending artery targets is the standard approach in coronary artery bypass grafting (CABG). 1 This conduit selection has been consistently shown to provide increased survival benefit and freedom from myocardial infarction, symptoms of ischemic heart disease, and reinterventions relative to CABG with SVGs only. 1 Although increasing evidence from observational cohort studies supports a survival advantage from bilateral internal thoracic artery (BITA) relative to SITA, 2 there still remains doubt as to whether BITA is the better choice for patients in the long term as the only randomized controlled trial to date evaluating long-term survival (the Arterial Revascularisa- tion Trial) is still ongoing. 3 Despite the increasing age of patients undergoing CABG these days, BITA is preferen- tially used for younger patients only. This is because the common perception of a survival benefit is limited to subjects with long life expectancy. 4 This aspect may partially account for the observed underuse of BITA grafts. 5 Whether the survival benefit from BITA is related to the patient’s age remains to be determined, however, as does any potential age cutoff for the loss of survival benefit from BITA. 6-8 This information is expected to provide evidence for the decision-making process in selecting patients for BITA. We aimed to investigate the potential benefit from BITA relative to the conventional strategy with SITA and SVGs in terms of long-term survival across patient age groups. MATERIALS AND METHODS Study Population The study was conducted in accordance with the principles of the Declaration of Helsinki. The local ethical committee approved the study, and the requirement for individual patient consent was waived. We retrospectively analyzed prospectively collected data from the institutional surgical database (PATS; Dendrite Clinical Systems, Ltd, Oxford, UK) from April 2001 to May 2013. The PATS database captures detailed information on a wide range of preoperative, intraoperative, and hospital postoperative variables (including complications and mortality) for all patients undergoing CABG in our institution. The data are collected and reported in accordance with the Society for Cardiothoracic Surgery in Great Britain & Ireland database criteria. The database is maintained by From the Department of Cardiac Surgery, Harefield Hospital, London, United Kingdom. Disclosures: Authors have nothing to disclose with regard to commercial support. Received for publication Jan 17, 2014; revisions received June 27, 2014; accepted for publication July 13, 2014; available ahead of print Sept 8, 2014. Address for reprints: Umberto Benedetto, MD, PhD, Department of Cardiac Surgery, Harefield Hospital, London UB9 6JH, United Kingdom (E-mail: umberto. benedetto@hotmail.com). 0022-5223/$36.00 Copyright Ó 2014 by The American Association for Thoracic Surgery http://dx.doi.org/10.1016/j.jtcvs.2014.07.088 2706 The Journal of Thoracic and Cardiovascular Surgery c December 2014 Acquired Cardiovascular Disease Benedetto et al ACD