Intraoperative imaging techniques to assess coronary artery bypass graft patency.

Graft patency verification is increasingly recognized as an important component of coronary artery bypass grafting. Intuitively, eliminating intraoperative graft failure should reduce cardiac mortality and morbidity in the short term and improve clinical outcome in the long term. Although conventional angiography remains the gold standard technique for assessing graft patency, it is rarely available in the operating room and consequently several other less invasive approaches have been advocated. This article reviews the two currently most commonly used modalities for graft patency assessment, intraoperative fluorescence imaging and transit-time flowmetry, and discusses their value and limitations. Both techniques can reliably detect otherwise unsuspected occluded grafts and this is crucial for internal thoracic arteries because of their prognostic significance. Although neither technology can consistently identify more minor, non-occlusive abnormalities, the intraoperative fluorescence imaging technique seems to be more sensitive and less susceptible to "false positive" images

Digital tools to facilitate intraoperative coronary artery bypass graft patency assessment.

Intraoperative graft failure is an important cause of cardiac mortality and morbidity. Hence, verification of graft patency should be one of the most important aspects of coronary artery bypass grafting. Although several techniques have been advocated to assess intraoperative graft patency, there is no unanimously accepted method. Intraoperative fluorescence imaging is a novel technique based on the fluorescence of indocyanine green dye, which provides real-time visual images of graft flow in the operating room. Transit-time flowmetry is based on the ultrasound principle and provides mean graft flow and derived values such as pulsatility index. This article describes the usefulness and limitations of various techniques in general and summarizes the current knowledge with the use of these two techniques in the setting of intraoperative coronary artery bypass graft patency assessment

Laser fluorescence angiography reveals perfusion defects in retrograde cardioplegia

Background: Adequate perfusion of the right ventricle with retrograde cardioplegia has always been questioned. However, clinical studies suggested sufficient protection and, up to now, intraoperative assessment of cardioplegia distribution has been difficult. Methods: As a pilot study in 14 patients, we used indocyanine green laser fluorescence angiography (ICGLA) to assess vascular and myocardial perfusion of different areas of the right anterior ventricular wall. Regions of interest were analyzed quantitatively using a new software package. Results: ICGLA allowed rapid and reliable visualization of cardioplegic flow and distribution. Retrograde cardioplegia revealed perfusion defects in the territory of the right anterior cardiac veins when compared to antegrade delivery and to areas close to the left anterior descending vein(s), confirmed by quantitative analyses of maximal fluorescence intensity. Five patients were excluded from quantitative analyses. The learning curve, pitfalls, limitations and special image details are described. Conclusion: A larger study is necessary to examine the relevance of perfusion defects to metabolic changes in affected myocytes and to global right ventricular function. </jats:p