Microvascular reperfusion injury: rapid expansion of anatomic no reflow during reperfusion in the rabbit.
The aim was to define the degree and time course of reperfusion-related expansion of no reflow. In five groups of anesthetized, open-chest rabbits (30-min coronary occlusion and different durations of reperfusion), anatomic no reflow was determined by injection of thioflavin S at the end of reperfusion and compared with regional myocardial blood flow (RMBF; radioactive microspheres) and infarct size (triphenyltetrazolium). The area of no reflow progressively increased from 12.2 +/- 4.2% of the risk area after 2 min of reperfusion to 30.8 +/- 3.1% after 2 h and 34.9 +/- 3.3% after 8 h and significantly correlated with infarct size after 1 h of reperfusion (r = 0.88-0.97). This rapid expansion of no reflow predominantly occurred during the first 2 h, finally encompassing approximately 80% of the infarct size, and was accompanied by a decrease of RMBF within the risk area, being hyperemic after 2 min of reperfusion (3.78 +/- 0.75 ml x min(-1) x g(-1)) and plateauing at a level of approximately 0.9 ml x min(-1) x g(-1) by 2 and 8 h of reperfusion (preischemic RMBF: 2.06 +/- 0.01 ml x min(-1) x g(-1)). The development of macroscopic hemorrhage lagged behind no reflow, was closely correlated with it, and may be the consequence of microvascular damage.
The Heart Institute, Good Samaritan Hospital, University of Southern California, Los Angeles, California 90017-2395, USA.
Thorsten
T
Reffelmann
Robert A
RA
Kloner
D000818:Animals; D052160:Benzothiazoles; D003326:Coronary Circulation / Q000502:physiology*; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D006470:Hemorrhage / Q000503:physiopathology; D008297:Male; D008833:Microcirculation / Q000502:physiology; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D015428:Myocardial Reperfusion Injury / Q000473:pathology / Q000503:physiopathology*; D011817:Rabbits; D013844:Thiazoles / Q000493:pharmacokinetics
D052160:Benzothiazoles; D005456:Fluorescent Dyes; D013844:Thiazoles; C009462:thioflavin T