Effects of distal embolization on the timing of platelet and inflammatory cell activation in interventional coronary no-reflow.
BACKGROUND
Myocardial hypoperfusion following percutaneous coronary intervention, termed "no-reflow", may be initiated by distal coronary embolization. This study examined the effects of distal embolization on the extent and timing of inflammation and platelet activation in an experimental model of coronary no-reflow.


METHODS
A no-reflow model was established in 9 Yorkshire pigs by injecting incremental doses of biologically inert polystyrene microspheres into the left anterior descending artery every 20 minutes via a transit catheter. A control group included 3 pigs that received corresponding intra-coronary boluses of normal saline. At predefined time points, coronary sinus blood samples were drawn and immediately analyzed by flow cytometry analysis for a panel of white blood cell and platelet activation markers, and the inflammatory cytokine TNFalpha.


RESULTS
No-reflow was achieved after delivery of 1,169,000+/-303,000 (range: 680,000 to 2,600,000) microspheres. In the distal embolization group, there were significant increases above baseline values in polymorphonuclear-platelet aggregates (146%-218%), in monocyte-platelet aggregates (51%-94%) and in TNFalpha levels (54%-84%) at multiple time points prior to no- reflow (15% cumulative dose and higher). For Annexin A5, there was a significant increase at 52% of cumulative dose (177% above baseline). Controls only showed one significant increase above baseline value for polymorphonuclear-platelet aggregates at the time of the last injection.


CONCLUSIONS
Widespread activation of interacting inflammatory and coagulation pathways following microsphere embolization occurred prior to the onset of angiographic no-reflow. This activation pattern cannot be attributed to prolonged coronary sinus instrumentation. Interactions between white blood cells (polymorphonuclears and monocytes) and platelets likely play an important role in the pathogenesis of no-reflow following distal embolization and may represent important therapeutic targets.
Charron
Thierry
T
Roy and Ann Foss Interventional Cardiology Research Program, University Health Network, University of Toronto, and Department of Hematology, St. Michael's Hospital, Toronto, Ontario, Canada.
Jaffe
Ronen
R
Segev
Amit
A
Bang
K W Annie
KW
Qiang
Beiping
B
Sparkes
John D
JD
Butany
Jagdish
J
Dick
Alexander J
AJ
Freedman
John
J
Strauss
Bradley H
BH
D000818:Animals; D001777:Blood Coagulation; D001792:Blood Platelets / Q000473:pathology; D003324:Coronary Artery Disease / Q000097:blood / Q000378:metabolism / Q000628:therapy; D003331:Coronary Vessels / Q000473:pathology; D006321:Heart / Q000502:physiology*; D007958:Leukocyte Count; D007962:Leukocytes / Q000378:metabolism / Q000473:pathology; D008297:Male; D009206:Myocardium / Q000473:pathology; D009919:Orchiectomy; D015539:Platelet Activation / Q000502:physiology*; D010976:Platelet Count; D034421:Sus scrofa