Near-infrared monitoring of myocardial oxygenation during ischemic preconditioning

Citation
M. Kawasuji et al., Near-infrared monitoring of myocardial oxygenation during ischemic preconditioning, ANN THORAC, 69(6), 2000, pp. 1806-1810
Citations number
14
Categorie Soggetti
Cardiovascular & Respiratory Systems","Medical Research Diagnosis & Treatment
Journal title
ANNALS OF THORACIC SURGERY
ISSN journal
00034975 → ACNP
Volume
69
Issue
6
Year of publication
2000
Pages
1806 - 1810
Database
ISI
SICI code
0003-4975(200006)69:6<1806:NMOMOD>2.0.ZU;2-I
Abstract
Background. Ischemic preconditioning has been advocated as a method of card ioprotection for minimally invasive direct coronary artery bypass. This stu dy was performed to estimate the cardioprotective effect of ischemic precon ditioning before ischemia by examining the changes in myocardial tissue oxy genation and-also to examine whether adenosine triphosphate-sensitive potas sium channel opener enhances the cardioprotective effect of ischemic precon ditioning. Methods. Myocardial ischemia was induced in three groups of 6 dogs by tempo rary occlusion of the left anterior descending coronary artery. Group I dog s received a 30-minute coronary occlusion and subsequent 3-hour reperfusion . Groups 2 and 3 dogs underwent three periods of 5-minute coronary occlusio n and Ei-minute reperfusion and then received 30-minute sustained ischemia and 3-hour reperfusion. In group 3, nicorandil was administered during the procedure. Myocardial oxygenation was measured using three-wavelength near- infrared spectroscopy. Myocardial blood now was measured by the colored mic rosphere method. Results. During ischemic preconditioning the myocardial tissue oxygen satur ation decreased rapidly at coronary occlusion and increased at reperfusion. It was increased stepwise at the second and third coronary occlusion. Myoc ardial oxygen saturation during 30-minute sustained ischemia was significan tly higher in groups 2 and 3 than in group 1 (p < 0.05). The myocardial tis sue hemoglobin concentration showed similar changes to myocardial oxygen sa turation. During 30-minute sustained ischemia, it was significantly higher in group 2 than in group 1 (p < 0.001), and it was significantly higher in group 3 than in groups 1 and 2 (p < 0.05). Regional myocardial blood flow s howed no difference after 30 minutes of sustained ischemia among the three groups. Troponin-T levels were significantly lower in groups 2 and 3 than i n group 1 (p < 0.01). Conclusions. Ischemic preconditioning had beneficial effects on myocardial oxygenation during sustained ischemia, and the protected state of the myoca rdium could be monitored with the use of near-infrared spectroscopy. Ischem ic preconditioning coupled with nicorandil administration might provide pro tection for minimally invasive direct coronary bypass. (C) 2000 by The Soci ety of Thoracic Surgeons.