CARDIOVASCULAR
ENGINEERING Journal for Extracorporeal Circulation, Assist Devices,Transplantation and Artificial Organs

Volume 5, 2000, No 4

Near-Infrared Spectroscopy of  Coronary Sinus Blood for Myocardial Ischemia Detection
D. Baykut, M.-M. Gebhard, K. Kadipasaoglu, O. H. Frazier, H.-R. Zerkowski

Background: The interruption of the  myocardial O2-supply leads to changes in the O2-content of coronary sinus blood.  In this study, the varying oxygenation status of coronary sinus blood in acute myocardial ischemia is evaluated  by near infrared (NIR)-spectroscopy.
Method:  For the intravascular access of the  NIR-spectral analysis, a  new fiberoptic catheter  is developed. In an in-vitro experiment, the catheter underwent a calibration test by perfusion of  blood with standardized gas mixtures (O2, CO2, N2).  For the spectroscopic evaluation of  ischemia under in-vivo-conditions, 10 domestic pigs were examined in an open-chest-procedure. The catheter was inserted into the coronary sinus and an anterior wall ischemia was induced by a temporary occlusion of LAD distal of the first diagonal branch. NIR-graphs and hemodynamic data were obtained for a 90 min ischemic period and 90 min reperfusion time.
Results: Different concentrations of O2  and CO2 in perfusion gases led to changes of  NIR-graphs under in-vitro conditions. The majority of spectral changes occurred under very low O2 -concentrations, resp. after complete elimination of O2 from blood by N2. The NIR-spectral analysis of the coronary sinus blood showed significant and reproducible differences between pre-ischemia, LAD-occlusion and following re-perfusion. Variations of NIR-graphs related to CO2-concentration, pH-value and temperature were also observed in in-vitro as well as in in-vivo experiments.
Conclusion: The intravascular NIR-spectral analysis of the coronary sinus blood with a fiberoptic catheter can be used as a reliable diagnostical tool for the online detection and follow-up of acute myocardial ischemia.

(CVE. 2000; 5 (4): 276-281)

Key words:  myocardial ischemia, near infrared, catheter

D. Baykut, M.D.
Department of  Cardiac and Thoracic Surgery
Kantonsspital Basel – Universitätskliniken
Spitalstraße 21
CH-4031  Basel
Switzerland

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