The effect of antiplatelet therapy on platelet accumulation after experimental angioplasty in the rabbit iliac model.
Antiplatelet therapy is routinely used in balloon angioplasty. Yet recent clinical trials have not shown these agents to reduce the incidence of restenosis. As this might be due to inadequate antiplatelet effect, this study was designed to evaluate the effectiveness of antiplatelet therapy in reducing platelet accumulation immediately after angioplasty. Sixty-six atherosclerotic rabbits underwent angioplasty of a focal (50-99%) iliac stenosis after pretreatment with an antiplatelet drug. The animals were randomly given aspirin (10 mg/kg orally) (n = 10), aspirin (10 mg/kg intravenously) (n = 7), aspirin (10 mg/kg per os) plus dipyridamole (25 mg orally) (n = 8), a thromboxane synthetase inhibitor (GS13080, 1 mg/kg/h intravenously) (n = 9) or heparin (500 U/kg intravenously) (n = 9). Platelet accumulation, determined by 51Cr-labeled platelet counts 30 min after angioplasty disclosed a significant reduction from control (44.1 +/- 51.2 platelets/cm x 10(6)) with intravenous aspirin (3.3 +/- 1.9; p less than 0.007) and the thromboxane synthetase inhibitor CGS13080 (15.1 +/- 16.6, p less than 0.04). Aspirin plus dipyridamole reduced platelet accumulation as well (10.4 +/- 9.8, p = 0.076), while oral aspirin (109.5 +/- 240) and heparin (34.7 +/- 35.5) were ineffective. The results of this study demonstrate that pretreatment with antiplatelet agents can reduce platelet accumulation significantly after experimental angioplasty. However, the wide variability in effectiveness particularly with oral aspirin may have important clinical implications. Further investigation into more effective antiplatelet therapy may help to reduce the incidence of abrupt vessel closure and restenosis.
Faxon
D P
DP
Evans Memorial Department of Clinical Research, University Hospital, Boston University Medical Center, Mallory Institute of Pathology, MA.
Balelli
L A
LA
Sandborn
T
T
Haudenschild
C
C
Valeri
R
R
Ryan
T J
TJ
D000800:Angioplasty, Balloon; D000818:Animals; D001161:Arteriosclerosis / Q000097:blood* / Q000628:therapy; D001241:Aspirin / Q000494:pharmacology; D004176:Dipyridamole / Q000494:pharmacology; D004195:Disease Models, Animal; D004338:Drug Combinations; D006493:Heparin / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology; D011817:Rabbits; D012008:Recurrence; D013930:Thromboxane-A Synthase / Q000037:antagonists & inhibitors; D013997:Time Factors
D004338:Drug Combinations; D007093:Imidazoles; D010975:Platelet Aggregation Inhibitors; D011725:Pyridines; D004176:Dipyridamole; D006493:Heparin; C037787:pirmagrel; D013930:Thromboxane-A Synthase; D001241:Aspirin