Coronary flow velocity patterns immediately after reperfusion reflect the pathologic characteristics of reperfused myocardium in canine models of acute myocardial infarction.
BACKGROUND
It is difficult to evaluate the extent of myocardial injury after successful reperfusion following acute myocardial infarction (AMI). We investigated the relationship between the coronary flow velocity pattern immediately after reperfusion and pathologic characteristics after myocardial reperfusion injury in dogs.


METHODS
We measured distal coronary flow velocity variables in the left circumflex coronary artery in a canine model of AMI (n = 12) 10 min after the release of a clamp (3-10 h clamp procedure) using a 0.35 mm Doppler guide-wire. Dogs were divided into two groups according to presence or absence of early systolic retrograde coronary flow. Hearts were excised 2 h after reperfusion and examined histopathologically.


RESULTS
The clamping time tended to be longer in dogs with early systolic retrograde coronary flow. Neutrophil infiltration was observed in the myocardium of dogs without systolic retrograde flow (n = 9); hemorrhage was rarely detectable and the myocardium maintained a bundle form. However, the bundle form of the myocardium became rough, and the severity of the incidence of hemorrhage tended to increase as the ratio of the diastolic coronary flow velocity to systolic velocity (DSVR) decreased. Vacuolar degeneration of the myocardium was also observed in hearts with a relatively low DSVR. In the group with systolic retrograde flow (n = 3), hearts were characterized by coagulation necrosis, marked vacuolar degeneration of the myocardium and diffusely distributed red cells in the intermyocytes. Systolic antegrade flow velocity was much reduced in this group, resulting in a markedly increased DSVR. These findings appeared to be related to severe myocardial damage.


CONCLUSIONS
Coronary flow velocity patterns immediately after successful reperfusion appear to reflect the pathologic characteristics of the reperfused myocardium in dogs with AMI.
Sakabe
K
K
Second Department of Internal Medicine, School of Medicine, University of Tokushima, Japan. sakabe@clin.med.tokushima-u.ac.jp
Wakatsuki
T
T
Shinohara
H
H
Ikata
J
J
Fujinaga
H
H
Oishi
Y
Y
Toyoshima
T
T
Nishikado
A
A
Oki
T
T
Ito
S
S
D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D004285:Dogs; D009203:Myocardial Infarction / Q000473:pathology / Q000628:therapy*; D015425:Myocardial Reperfusion; D015428:Myocardial Reperfusion Injury / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D013997:Time Factors; D014463:Ultrasonography