Proximal coronary hemodynamic changes evaluated by intracardiac echocardiography during myocardial ischemia and reperfusion in a canine model.
BACKGROUND
The purpose of this study was to assess whether the dynamic changes in coronary flow velocity and coronary flow velocity reserve (CFVR) by intracardiac echocardiography (ICE) within proximal coronary arteries are related to myocardial perfusion status and infarct size in a myocardial ischemia-reperfusion injury model.


METHODS
In 14 dogs, left anterior descending coronary artery (LAD) was ligated for 2 hours followed by 2 hours reperfusion. Coronary flow velocity was obtained by ICE within coronary arteries at baseline, and at the end of both occlusion and reperfusion period. The CFVR was calculated as the ratio of hyperemic to resting peak diastolic velocity (PDV). Myocardial perfusion was evaluated by real time myocardial contrast echocardiography (MCE). The infarct area was detected by triphenyltetrazolium chloride (TTC) staining and expressed as the percentage of the whole left ventricular (LV) area.


RESULTS
CFVR significantly decreased both in proximal LAD and left circumflex (LCx) artery at the end of occlusion, and did not recover at the end of reperfusion. However, no significant difference in flow parameters was observed between dogs with myocardial perfusion defect and those without. CFVR in LAD at the end of reperfusion did not correlate with the infarct size (r =-0.182, P = NS) either.


CONCLUSIONS
Decreased CFVR detected by ICE occurs both in ischemic and in nonischemic proximal arteries during myocardial ischemia and early stage of reperfusion. This change in CFVR has poor correlation with the extent of microvascular impairment and cannot be used to predict infarct size.
Han
Beibei
B
Department of Cardiology, Shanghai 6th People's Hospital, Shanghai Jiaotong University, Shanghai, PR China.
Wei
Meng
M
D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D003287:Contrast Media; D003326:Coronary Circulation; D004285:Dogs; D015150:Echocardiography, Doppler / Q000379:methods; D006339:Heart Rate; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000473:pathology; D010743:Phospholipids; D013459:Sulfur Hexafluoride
D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride