Online Detection of Myocardial Ischemia by Near Infrared
Spectroscopy with a Fiberoptic Catheter

Background: The interruption of myocardial O₂-supply in acute myocardial ischemia causes differences in coronary venous O₂-content. In this study, the oxygenation status of coronary sinus blood is detected in myocardial ischemia by near infrared (NIR) spectroscopy. Method: For the intravascular application, a new fiberoptic catheter is developed. After calibration of the catheter by perfusion of blood with standardized gas mixtures in an in vitro experiment, the in vivo application was performed in 12 domestic pigs. The catheter was placed into coronary sinus and an anterior ischemia was induced by temporary occlusion of LAD. NIR graphs and hemodynamic data were obtained for 90 min ischemia and 90 min reperfusion time. Results: Main NIR-spectroscopic differences between oxygenated and de-oxygenated hemoglobin took place in O₂-concentrations less than 30 %. Coronary sinus NIR spectra of hemoglobin-oxygen binding showed significant, reproducible differences between pre-ischemia, LAD-occlusion and reperfusion. NIR graphs also show variations related to CO₂-concentration, pH and temperature. Conclusion: The intravascular application of NIR spectroscopy could be a reliable tool in detection and follow-up of acute myocardial ischemia and infarction.

Key words:

Near infrared - Detection - Myocardial ischemia

References

• 1 Cope M, Delpy D T. System for long-term measurement of cerebral blood and tissue oxygenation on newborn infants by near infra-red transillumination.  Med Biol Eng Comput. 1988;  26 289-294
• 2 Gagnon R E, Gagnon F A, Macnab A J. Comparison of 13 published cytochrome c oxidase near-infrared spectroscopy algorithms.  Eur J Appl Physiol. 1996;  74 487-495
• 3 Irwin M S, Thorniley M S, Doré C J, Green C J. Near infra-red spectroscopy: a non-invasive monitor of perfusion and oxygenation within the microcirculation of limbs and flaps.  Br J Plastic Surg. 1995;  48 14-22
• 4 Jöbsis F F. Non-invasive, infra-red monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters.  Science. 1977;  198 1264-1267
• 5 Macnab A J, Leblanc J, Gagnon F A, Gagnon R E. Near infrared spectroscopy oxidized cytochrome aa₃ patterns of change during cardiac surgery in children.  Pediatr Res. 1995;  38 442
• 6 Matcher S J, Elwell C E, Cooper C E, Cope M, Delpy D T. Performance comparison of several published tissue near-infrared spectroscopy algorithms.  Anal Biochem. 1995;  227 54-68
• 7 Parsons W J, Rembert J C, Bauman R P, Greenfield J C, Piantadosi C A. Dynamic mechanisms of cardiac oxygenation during brief ischemia and reperfusion.  Am J Physiol. 1990;  259 1477-1485
• 8 Parsons W J, Rembert J C, Bauman R P, Duhaylongsod F G, Greenfield J C, Piantadosi C A. Myocardial oxygenation in dogs during partial and complete coronary artery occlusion.  Circ Res. 1993;  73 458-464
• 9 Rhee P, Langdale L, Mock C, Gentilello L M. Near-infrared spectroscopy: Continuous measurement of cytochrome oxidation during hemorrhagic shock.  Crit Care Med. 1997;  25 166-170
• 10 Seiyama A, Hazeki O, Tamura M. Noninvasive quantitative analysis of blood oxygenation in rat skeletal muscle.  J Biochem. 1988;  103 419-424
• 11 Thorniley M S, Lahiri A, Glenville B, Shurey C, Baker G, Ravel U, Crawley J, Green C J. Non-invasive measurement of cardiac oxygenation and hemodynamics during transient episodes of coronary artery occlusion and reperfusion in the pig.  Clinical Science. 1996;  91 51-58
• 12 Van der Zee P, Arridge S R, Cope M, Delpy D T. The effect of optode positioning on optical pathlength in near infrared spectroscopy of brain. In: Ed. By Püper J et al. Oxygen Transport to Tissue XII. Plenum Press, New York 1990: 79-84
• 13 Wray S, Cope M, Delpy D T, Wyatt J S, Reynolds E OR. Characterization of the near infrared absorption spectra of cytochrome aa₃ and haemoglobin for the non-invasive monitoring of cerebral oxygenation.  Biochim Biophys Acta. 1988;  933 184-192