Objectives The intravascular application of near-infrared spectroscopy was previously evaluated in acute ischemia-reperfusion studies in animal experiments. The objective of our study was to assess the technical feasibility and clinical reliability of an online myocardial ischemia monitoring by using intravascular near-infrared spectroscopy during off-pump coronary bypass surgery. Methods Intravascular near-infrared spectroscopy of coronary sinus blood was performed in 10 elective patients selected for off-pump coronary bypass surgery. Light signals were transferred through a fiberoptic catheter for emission and collection from the coronary sinus blood. Spectrometric analyses were performed before and after revascularization with internal thoracic artery and saphenous vein grafts. Changes in spectroscopic data were compared with hemodynamic parameters and electrocardiographic, transesophageal echocardiographic, and laboratory findings. Results All of the operations were finished as off-pump procedures. No remarkable intraoperative myocardial ischemia was observed in the patient group, as indicated by electrocardiography and transesophageal echocardiography. Reproducible absorption spectra of coronary sinus blood were obtained at every defined step of the surgical procedure. Clear ischemia-related changes were detected in none of the patients. Conclusions Our initial results showed that intravascular near-infrared spectroscopic ischemia monitoring is technically feasible. However, the method must be further evaluated and standardized under varying conditions to determine the role of near-infrared spectroscopy as an ischemia monitoring tool in off-pump coronary bypass surgery.
The prevalence and prognostic significance of silent myocardial ischemia after coronary bypass surgery
