Sundell IB, Marzec UM, Kelly AB, Chronos NA, Petersen LC, Hanson SR, Hedner U, Harker LA. Reduction in stent and vascular graft thrombosis and enhancement of thrombolysis by recombinant Lys-plasminogen in nonhuman primates.
Circulation 1997;
96:941-8. [PMID:
9264505 DOI:
10.1161/01.cir.96.3.941]
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Abstract
BACKGROUND
To enhance thrombolytic responses without increasing hemorrhagic risks, the antithrombotic effects of recombinant Lys-plasminogen (r-LysPgn), a prothrombolytic plasminogen intermediate, were examined in baboon models of thrombus formation and dissolution.
METHODS AND RESULTS
The dose-response effects of r-LysPgn, alone or in combination with subthreshold dosing of tissue plasminogen activator (TPA), were measured with respect to the accumulation of (111)In-labeled platelets and (125)I-fibrin in thrombus forming on endovascular metallic stents or thrombogenic segments of vascular graft interposed in exteriorized long-term arteriovenous (AV) femoral shunts. Thrombolytic losses have also been determined for preformed, stable, (111)In-platelet- and (125)I-fibrin-labeled graft thrombus and corresponding propagated thrombotic tails, together with changes in blood tests of thrombosis, thrombolysis, and hemostasis. Bolus intravenous r-LysPgn in escalating doses (2, 4, or 8 mg/kg) increased circulating plasminogen levels in a dose-dependent manner, was removed by log-linear clearance with a T50 of 120 minutes, and reciprocally decreased the accumulating thrombus on metallic stents and segments of vascular graft (P<.001 in all cases for 8-mg/kg doses). r-LysPgn also impaired platelet aggregatory responses to physiological agonists in vitro but not ex vivo. Prethrombosis administration of low-dose r-LysPgn (2 mg/kg) greatly enhanced the lysis of radiolabeled nonoccluding thrombus by a subthreshold dose of TPA (0.1 mg/kg) compared with TPA-only controls (P=.03).
CONCLUSIONS
Elective bolus injections of r-LysPgn before stent deployment decrease the amount of thrombus formed without compromising hemostasis by facilitating endogenous TPA thrombolysis. r-LysPgn may provide effective and safe antithrombotic therapy for interventional vascular procedures.
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