I.V. NIRS off-pump coronary artery ischemia monitoring bypass surgery

Abstract

INTRODUCTIONNear-infrared (NIR) spectroscopy is an appropriate method for ischemia monitoring in myocardial tissue. 1 An acute deterioration of coronary blood supply can result in a release of ischemic metabolites, predominantly oxygen-dependent chromophores into the coronary sinus. These metabolites are detectable in the coronary sinus blood, often prior to the appearance of substances representing cellular injury such as troponins and creatine kinase (CK-MB) in the peripheral blood. The online intravascular NIR spectroscopic analysis of the coronary sinus blood with a fiberoptic catheter allows a direct ischemia monitoring at myocardial level. 2 The aim of present study was to evaluate the clinical reliability of myocardial ischemia monitoring by using intravascular NIR spectroscopy in OPCAB surgery. The intraoperative management of hemodynamic changes in off-pump ABSTRACT Background: Spectroscopic data were compared with hemodynamic parameters, electrocardiogram, transesophageal echocardiography and laboratory findings. A conversion to extracorporeal circulation was not necessary. The mean number of grafts per patient was 3.1±0.6. An intraoperative myocardial ischemia was not evident, as indicated by electrocardiogram and transesophageal echocardiography. Methods: Continuous spectroscopic analysis showed reproducible absorption spectra of coronary sinus blood. Due to uneventful intraoperative courses, clear ischemia-related changes could be detected in none of the patients. Present initial results show that intravascular near-infrared spectroscopy can reliably be used for an online intraoperative ischemia monitoring in off-pump coronary artery bypass surgery. Results: In 15 elective patients undergoing off-pump myocardial revascularization, intravascular near-infrared spectroscopic analysis of coronary venous blood was performed. NIR signals were transferred through a fiberoptic catheter for signal emission and collection. For data analysis and processing, a miniature spectrophotometer with multivariate statistical package was used. Signal acquisition and analysis were performed before and after revascularization. However, the method has to be further evaluated and standardized to determine the role of spectroscopy in off-pump coronary artery bypass surgery. In off-pump coronary artery bypass surgery, manipulations on the beating heart can lead to transient interruptions of myocardial oxygen supply, which can generate an accumulation of oxygen-dependent metabolites in coronary venous blood. Conclusions: The objective of this study was to evaluate the reliability of intravascular near-infrared spectroscopy as a monitoring method to detect possible ischemic events in off-pump coronary artery bypass procedures.