Inhibition of thrombin attenuates stenosis after arterial injury in minipigs.
OBJECTIVE
We sought to determine whether brief, profound inhibition of thrombin or prothrombin activation by factor Xa limits neointimal formation and stenosis after arterial injury.


BACKGROUND
Thrombin has been implicated as a mediator of neointimal formation, but adjunctive administration of anticoagulant agents has not proven effective to decrease restenosis in patients undergoing coronary angioplasty.


METHODS
We infused recombinant desulfatohirudin (r-hirudin, bolus of 2 mg/kg body weight followed by 2 mg/kg per h, n = 9), heparin (100 U/kg per h, n = 6) or recombinant tick anticoagulant peptide (rTAP, 1-mg/kg bolus followed by 3 mg/kg per h, n = 5), a specific inhibitor of factor Xa, intravenously, beginning 15 min before and for up to 3 h after repetitive balloon hyperinflations sufficient to disrupt the internal elastic lamina in a carotid artery of minipigs with hypercholesterolemia induced by feeding them an atherogenic diet.


RESULTS
Partial thromboplastin time was increased six- to sevenfold over baseline levels at the end of the infusions of the anticoagulant agents. Lumen stenosis measured histologically 4 weeks after balloon-induced carotid injury was 29 +/- 16% (mean +/- SEM) in r-hirudin-treated, 52 +/- 19% in rTAP-treated and 76 +/- 18% in heparin-treated pigs (p < 0.02 for r-hirudin vs. heparin treatment).


CONCLUSIONS
The marked reduction of stenosis in r-hirudin-treated animals indicates that thrombin plays a major role in neointimal formation after balloon-induced arterial injury. A relatively brief interval of profound, direct inhibition of thrombin may be particularly effective to attenuate restenosis after balloon angioplasty.
Abendschein
D R
DR
Department of Internal Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110, USA.
Recchia
D
D
Meng
Y Y
YY
Oltrona
L
L
Wickline
S A
SA
Eisenberg
P R
PR
D000800:Angioplasty, Balloon / Q000009:adverse effects; D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D060829:Arthropod Proteins; D002339:Carotid Arteries / Q000473:pathology; D020212:Carotid Artery Injuries; D016893:Carotid Stenosis / Q000097:blood / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D015951:Factor Xa / Q000494:pharmacology*; D065427:Factor Xa Inhibitors; D006493:Heparin / Q000494:pharmacology; D006629:Hirudins / Q000031:analogs & derivatives / Q000494:pharmacology; D006937:Hypercholesterolemia / Q000150:complications; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D010314:Partial Thromboplastin Time; D010455:Peptides / Q000494:pharmacology; D011516:Prothrombin / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000494:pharmacology; D013552:Swine; D013556:Swine, Miniature; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000502:physiology*; D017539:Tunica Intima / Q000187:drug effects / Q000473:pathology
D000925:Anticoagulants; D060829:Arthropod Proteins; D065427:Factor Xa Inhibitors; D006629:Hirudins; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D011994:Recombinant Proteins; C063967:tick anticoagulant peptide; D011516:Prothrombin; D006493:Heparin; D013917:Thrombin; D015951:Factor Xa; C060225:desirudin