Angiography During Cardiovascular Surgery

Abstract

Intraoperative fluorescence imaging (IFI) is currently indicated as a tool to determine the patency of coronary artery bypass grafts. Graft patency is the major determinant of survival and freedom from repeat intervention after coronary artery bypass grafting (CABG) (Desai et al. J Am Coll Cardiol 46;1521–1525, 2005). Unfortunately, early graft failure after coronary artery bypass grafting is common. The PREVENT IV study revealed that at 1 year up to 26% of coronary bypass grafts will be closed (PREVENT IV Investigators. JAMA 294:2446–2454, 2005). Interestingly, the 30-day mortality outcomes were excellent in the trial (PREVENT IV Investigators. JAMA 294:2446–2454, 2005). However, the subgroup with graft failure had twice the rate of perioperative myocardial infarction (MI) and four times the risk of death, MI, and need for revascularization at 1 year. Significant advances in medical therapy including early postoperative aspirin administration, statin use, and increased use of arterial grafting have improved early and late graft patency (Taggart DP. J Thorac Cardiovasc Surg 120:651–659, 2000; Yusuf et al. Lancet 344;563–570, 1994; Lytle et al. J Thorac Cardiovasc Surg 117:855, 1999; Taggart et al. Lancet 358:870–875, 2001). However, technical errors in bypass graft construction by the operating surgeon are primarily responsible for the majority of these early failures (Puskas et al. JAMA 291:1841–1849, 2004; Khan et al. N Engl J Med 350:21–28, 2004). With the exception of coronary artery bypass surgery, virtually all other interventions on the heart, including cardiac valve repair/replacement and coronary stenting, are accompanied by completion diagnostic imaging to ensure an adequate technical result. Despite tremendous improvements in the quality of processes of care in cardiac surgery over the past decade, there are still no well-accepted or broadly used techniques to assess the quality of the bypass graft itself. Recent angiographic trials by Puskas et al. (JAMA 291:1841–1849, 2004) and Khan et al. (N Engl J Med 350:21–28, 2004) have shown significant clustering of the technical results of off-pump surgery at the level of the individual surgeon, highlighting the need for intraoperative quality assurance. Since graft patency is the predominant predictor of long-term survival after coronary surgery, a well-validated method to assess graft patency in coronary surgery remains an important opportunity for improving quality assurance (Lytle et al. J Thorac Cardiovasc Surg 103(5):831–840, 1992; Halabi et al. Am J Cardiol 96:1254–1259, 2005). We will discuss the use of intraoperative fluorescence imaging as a method of assessing real-time coronary artery bypass grafts as well as the quantification of improved myocardial blood flow. We will also discuss the other currently available methods of assessing early graft patency and compare them to intraoperative fluorescence imaging.