Limitation of infarct size by fixed coronary arterial stenosis maintained during reperfusion.
BACKGROUND
The effect on infarct size of a pre-infarction high-grade, fixed coronary arterial stenosis maintained during reperfusion, was evaluated.


METHODS
This experimental study was carried out in the research laboratory of a University Hospital. A canine occlusion-reperfusion model was used. Twenty-eight dogs underwent proximal left anterior descending (LAD) coronary artery occlusion (O). In Group 1 (n=6) the O lasted for 6 hours. In Group 2 (n=6) the O lasted for 2 hours followed by 4 hours of reperfusion (R). In Group 3 (n=3), LAD was stenosed for 30 minutes followed by O for 6 hours. In Group 4 (n=7) LAD was stenosed for 30 minutes followed by O for 2 hours and then 4 hours of R during which the artery was kept stenosed at the same degree (fixed) as the initial one. In Group 5 (n=6) the protocol was identical to Group 4 with the additional use of the intra-aortic balloon pump during R.


RESULTS
The infarcted myocardium was almost the same in Groups 1 and 3 (80.0+/-10.6% vs 77.3+/-3.8%, respectively, p=NS), but less in Group 2 (59.0+/-19.9%, p=0.046 vs Group 1). There were no hemodynamic differences between Groups 4 and 5 and the infarcted myocardium was almost identical in both groups (37.7+/-18.8% and 38.7+/-19.1%, respectively, p=NS). The combined results of Groups 4 and 5, regarding the infarcted myocardium, was 38.1+/-18% (p=0.037 vs Group 2).


CONCLUSIONS
In this acute coronary occlusion model, a pre-existing high-grade stenosis that maintained during reperfusion increased the amount of salvaged ischemic myocardium.
Nanas
J N
JN
Department of Clinical Therapeutics, University of Athens School of Medicine, Athens, Greece.
Nanas
S N
SN
Kontoyannis
D A
DA
Moussoutzani
K S
KS
Rapti
A C
AC
Charitos
C E
CE
Terrovitis
J V
JV
Stamatelopoulos
S F
SF
Moulopoulos
S D
SD
D000818:Animals; D001158:Arteries / Q000473:pathology; D003250:Constriction; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000473:pathology*; D004285:Dogs; D006439:Hemodynamics; D019157:Ischemic Preconditioning, Myocardial; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy; D015425:Myocardial Reperfusion; D015428:Myocardial Reperfusion Injury / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D009206:Myocardium / Q000473:pathology*