Inhibition of platelet aggregation by combined therapy with aspirin and cilostazol after off-pump coronary artery bypass surgery.
BACKGROUND
Although off-pump coronary artery bypass (OPCAB) has become an increasingly common surgical procedure, recent concerns have been raised regarding the existence of a hypercoagulable or prothrombotic state associated with OPCAB. To determine the optimal antiplatelet regimen after OPCAB, we investigated the effects of aspirin alone and of combined therapy with aspirin + cilostazol on platelet aggregation in patients after OPCAB.


METHODS
Twenty patients scheduled to undergo OPCAB were randomized to one of two antiplatelet regimens: aspirin alone (n=10) and aspirin + cilostazol (n=10). Anti-platelet agents had not been received for at least 1 week before surgery and were initiated on the afternoon of postoperative day 1. Platelet aggregability and hemostatic parameters were evaluated at four time points: before and 3, 7, and 14 days after OPCAB. We measured agonist-and shear stress-induced platelet aggregation (SIPA) using a modified cone-plate viscometer.


RESULTS
No complications resulting from postoperative antiplatelet therapy-related bleeding were seen in either group. Collagen-and arachidonate-induced platelet aggregation and SIPA were significantly inhibited in the aspirin + cilostazol group compared with the aspirin-alone group (collagen-and arachidonate-induced aggregation, p<0.0001; SIPA, p=0.0367). Adding cilostazol to aspirin augmented the inhibitory effects on platelet aggregation induced by collagen and arachidonate. adenosine diphosphate (ADP)-induced platelet aggregation tended to be inhibited in the aspirin + cilostazol group compared with the aspirin-alone group (p=0.0534).


CONCLUSIONS
The results of this study suggest that combined therapy with aspirin + cilostazol is more effective than aspirin monotherapy in reducing platelet aggregation in patients after OPCAB. This combination therapy may represent a new therapeutic option for an anti-thrombotic regimen in patients after OPCAB.
Onoda
Koji
K
Department of Thoracic and Cardiovascular Surgery, Mie University Graduate School of Medicine, Tsu, Mie, Japan.
Ohashi
Kayoko
K
Hashimoto
Akira
A
Okuda
Masahiro
M
Shimono
Takatsugu
T
Nishikawa
Masakatsu
M
Shimpo
Hideto
H
D000368:Aged; D001241:Aspirin / Q000627:therapeutic use*; D000077407:Cilostazol; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects*; D004359:Drug Therapy, Combination; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D010976:Platelet Count; D010979:Platelet Function Tests; D013777:Tetrazoles / Q000627:therapeutic use*; D013927:Thrombosis / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors; D016896:Treatment Outcome; D014841:von Willebrand Factor / Q000378:metabolism
D010975:Platelet Aggregation Inhibitors; D013777:Tetrazoles; D014841:von Willebrand Factor; D005340:Fibrinogen; D000077407:Cilostazol; D001241:Aspirin