| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Thrombosis |
From the Department of Pharmacology, Merck Research Laboratories, West Point, Pa.
Correspondence to You-Tang Shen, MD, Department of Pharmacology, Merck Research Laboratories, WP46-200, West Point, PA 19486. E-mail youtang_shen{at}merck.com
AbstractThrombosis resulting
from blood platelet aggregation via glycoprotein (GP)
IIb/IIIa receptor activation triggers the local release of vasoactive
substances. Therefore, inhibition of these receptors could affect
coronary vasoactive function during thrombotic coronary
arteriostenosis. Twenty pigs were instrumented with an aortic
catheter and with hydraulic occluders and flow probes on both the left
anterior descending (LAD) and the left circumflex (LCx)
coronary arteries. One of these 2 coronary arteries was
repeatedly injured by external clamping for 15-second periods at
30-minute intervals while the pigs were given either a GP IIb/IIIa
receptor inhibitor (L-739,758) (n=5), heparin (n=5),
aspirin (n=3), or saline (n=7). There were no baseline differences
between the 4 groups in mean arterial pressure, resting
coronary blood flow (CBF), or reactive hyperemic
response (RHR), which was induced by brief coronary artery
occlusion and expressed as flow debt repayment. After multiple
injuries, resting CBF had decreased by 95±2% (ie, nearly complete
coronary artery occlusion) at 15±4 minutes in the control
group, whereas in the heparin-, aspirin-, and GP IIb/IIIa
inhibitortreated groups, resting CBF had decreased by
only 21±7% at 18±3 minutes, 15±3% at 18±5 minutes, and 15±7% at
21±4 minutes, respectively, suggesting that heparin, aspirin, and the
GP IIb/IIIa inhibitor each prevented injury-induced
coronary artery occlusion. After the initial injury, the RHR
was progressively reduced in the control and heparin- and
aspirin-treated groups but not in the GP IIb/IIIa
inhibitortreated group. At a comparable level of resting
CBF (
15% below baseline), the RHR was reduced more in the control
(-56±9%), heparin-treated (-49±9%), and aspirin-treated
(-61±12) groups (P<0.05) than in the GP IIb/IIIa
inhibitortreated group (-26±6%). When the resting CBF
had decreased by
35%, the RHR still was reduced significantly more
(P<0.01) in the heparin-treated group (-64±9%) than
in the GP IIb/IIIa inhibitortreated group (-21±6%). In
a separate group of control pigs (n=4) subjected to 2 injuries,
coronary perfusion pressure distal to the injury site was
reduced by 14±1 mm Hg from the arterial pressure,
and the RHR was 20±6%. When the distal coronary perfusion
pressure was reduced similarly (-14±1 mm Hg) in a separate
group of GP IIb/IIIa inhibitortreated pigs (n=4) by 2
injuries and the use of a hydraulic occluder, the RHR was 130±16%
(P<0.01 versus control). Our data demonstrate for the
first time that a platelet GP IIb/IIIa receptor
inhibitor can preserve the distal coronary
vasodilatory response during progressive coronary arteriostenosis.
Key Words: coronary reactive hyperemia coronary reserve heparin aspirin coronary injury glycoprotein IIb/IIIa
This article has been cited by other articles:
![]() |
H. Kunichika, O. Ben-Yehuda, S. Lafitte, N. Kunichika, B. Peters, and A. N. DeMaria Effects of glycoprotein iib/iiia inhibition on microvascular flow after coronary reperfusion: A quantitative myocardial contrast echocardiography study J. Am. Coll. Cardiol., January 21, 2004; 43(2): 276 - 283. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Heitzer, I. Ollmann, K. Koke, T. Meinertz, and T. Munzel Platelet Glycoprotein IIb/IIIa Receptor Blockade Improves Vascular Nitric Oxide Bioavailability in Patients With Coronary Artery Disease Circulation, August 5, 2003; 108(5): 536 - 541. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. A. Barrabes, D. Garcia-Dorado, M. Mirabet, R.-M. Lidon, B. Soriano, M. Ruiz-Meana, P. Pizcueta, J. Blanco, Y. Puigfel, and J. Soler-Soler Lack of effect of glycoprotein IIb/IIIa blockade on myocardial platelet or polymorphonuclear leukocyte accumulation and on infarct size after transient coronary occlusion in pigs J. Am. Coll. Cardiol., January 2, 2002; 39(1): 157 - 165. [Abstract] [Full Text] [PDF] |
||||
|
ATVB Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search Copyright © 2000 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |