This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Abendschein, D. R. Articles by Sobel, B. E. Search for Related Content PubMed PubMed Citation Articles by Abendschein, D. R. Articles by Sobel, B. E.

(Circulation. 1995;92:944-949.)
© 1995 American Heart Association, Inc.

Articles

Maintenance of Coronary Patency After Fibrinolysis With Tissue Factor Pathway Inhibitor

Dana R. Abendschein, PhD; Yuan Yuan Meng, MD; Sheryl Torr-Brown, PhD; Burton E. Sobel, MD

From the Cardiovascular Division, Washington University School of Medicine, St Louis, Mo.

Correspondence to Dana R. Abendschein, PhD, Washington University School of Medicine, Cardiovascular Division, PO Box 8086, 660 S Euclid Ave, St Louis, MO 63110.

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Background Pharmacological coronary fibrinolysis induces procoagulant effects that contribute to delayed recanalization and early reocclusion. This study was designed to determine whether brief inhibition of activation of the coagulation cascade with tissue factor pathway inhibitor, a physiological inhibitor of activated factor X and its activation by the tissue factor/factor VII complex, would facilitate fibrinolysis, sustain patency of recanalized arteries, or both.

Methods and Results Platelet-rich coronary thrombi were induced with anodal current that elicited intimal injury in 21 conscious dogs. Each was randomized to human recombinant tissue-type plasminogen activator (rTPA 1.0 mg/kg IV over 1 hour) with infusion of 50 µg · kg^-1 · min^-1 of human recombinant tissue factor pathway inhibitor (rTFPI, n=7), 100 µg · kg^-1 · min^-1 of rTFPI (n=8), or 300 mmol/L arginine phosphate buffer as a control (n=6) concomitant with and for 1 hour after infusion of the plasminogen activator. Recanalization, verified with proximal Doppler flow probes, occurred in all but 1 dog given the high dose of rTFPI. It was not accelerated by conjunctive rTFPI. Reocclusion occurred within 90 minutes after infusion of rTPA in all 6 control dogs. However, reocclusion was delayed and patency was sustained for the entire 24-hour observation interval in 2 of 6 dogs (excluding 1 that did not survive) given the low dose and in 4 of 6 dogs (excluding 1 that did not receive the desired amount) given the high dose of rTFPI (P<.05 compared with controls). Cyclic flow variations indicative of platelet aggregation and disaggregation locally were virtually eliminated by rTFPI (3±4[SD]/h in dogs given the low dose and 2±2/h in those given the high dose of rTFPI compared with 13±12/h in controls, P<.05). In addition, rTFPI increased activated partial thromboplastin time and prothrombin time only at the high dose (1.4±0.3 and 2.1±0.9 times baseline) and had no effects on platelet aggregation assayed ex vivo and only minimal effects on bleeding time assayed in vivo.

Conclusions Brief inhibition of the coagulation system by administration of rTFPI sustains patency of arteries recanalized by pharmacological fibrinolysis without markedly perturbing hemostatic mechanisms.

Key Words: thrombolysis • plasminogen activators • anticoagulants

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
The efficacy of pharmacological fibrinolysis for treatment of acute myocardial infarction is limited by lack of adequate coronary recanalization in a significant minority of patients and by early thrombotic reocclusion in others despite administration of heparin.^{1 2} In addition, early withdrawal of heparin after initially successful fibrinolysis is frequently associated with recurrent ischemia, indicative of ongoing thrombosis.³

Such phenomena appear to reflect procoagulant activity attributable, in part, to thrombin generated de novo during fibrinolysis or associated with residual thrombus, or both. Thus, studies in experimental animals^{4 5} and preliminary clinical trials^{6 7 8} in which direct (and more potent than heparin) inhibitors of thrombin such as recombinant desulfatohirudin or Hirulog were given in conjunction with fibrinolytic agents have reported improved patency of the infarct-related artery. However, we have shown⁹ that thrombi are composed of much more activated factor X (factor Xa) than thrombin, which, coupled with the tissue factor/activated factor VII (factor VIIa) complex exposed at sites of vessel injury, may exert profound and persistent procoagulant effects despite inhibition of preformed thrombin.

Inhibition of the tissue factor/factor VIIa complex as well as factor Xa in vivo is mediated by tissue factor pathway inhibitor (TFPI, previously called lipoprotein-associated coagulation inhibitor and extrinsic coagulation pathway inhibitor), a 276–amino acid, 32-kD glycoprotein present on endothelium (50% to 90% of the total TFPI in vivo) and circulating at low levels in blood (100 ng/mL in humans, 20 ng/mL in dogs) bound to HDL (10% to 50% of total) and platelets (<3% of total).^{10 11 12} It is composed of three tandem Kunitz-type inhibitory domains; the first binds factor VIIa, and the second binds factor Xa.¹³ The function of the third domain is not known. Heparin displaces TFPI from endothelium.^{14 15} However, the amount of TFPI released into the circulation by heparin administration may not be sufficient to attenuate coagulation after fibrinolysis.

We have found that intravenous infusion of human recombinant TFPI (rTFPI) prevents reocclusion over an interval of 2 hours after pharmacological fibrinolysis of platelet-rich thrombi induced by electrical injury of femoral arteries in dogs.¹⁶ However, rTFPI was less effective in minimally injured arteries after fibrinolysis of fibrin-rich thrombi.¹⁶ This study was designed to determine whether rTFPI could enhance maintenance of patency after coronary fibrinolysis.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Preparation of rTFPI
Human rTFPI was expressed in Escherichia coli¹⁷ as a nonglycosylated protein with an additional alanine attached to the amino-terminus of wild-type TFPI. It was purified by anion-exchange chromatography, refolded through a disulfide interchange reaction, and resolved from relatively inactive and misfolded molecules on a Mono S cation-exchange chromatography column. The E. coli–produced rTFPI exhibited specific activity 3 to 10 times higher than rTFPI obtained by transfecting mammalian cell lines and 2 times higher activity, on a molar basis, than that of full-length SK hepatoma–derived TFPI in a tissue factor–induced clotting assay in human plasma.¹⁷ The rTFPI used was formulated in 300 mmol/L arginine phosphate buffer at pH 7.2 and diluted to a final concentration averaging 5 mg/mL.

Animal Preparations
All procedures were conducted according to the guiding principles of the American Physiological Society and approved by the Animal Studies Committee at Washington University. Mongrel dogs of either sex between 6 months and 3 years of age and weighing 20 to 25 kg were premedicated with acepromazine maleate (0.1 mg/kg SC) and atropine sulfate (0.04 mg/kg SC) after an overnight fast. Anesthesia was induced with thiopental (12.5 mg/kg IV) and maintained with isoflurane (1.5% to 2%) in oxygen-enriched room air delivered by a mechanical ventilator. Catheters were placed aseptically in a common carotid artery and an external jugular vein. The heart was exposed through a left thoracotomy in the fourth intercostal space and suspended in a pericardial cradle. A segment of the left anterior descending coronary artery above the midventricular diagonal branch was dissected free from surrounding tissue. Small side branches were ligated. A 20- MHz Doppler flow probe (purchased from Craig Hartley, PhD, Baylor College of Medicine, Houston, Tex) was placed proximally around the vessel. A needle electrode, consisting of the tip (2 cm) of a 23-gauge needle bent at a 90° angle and crimped onto the end of a 6-cm length of 30-gauge Teflon-insulated silver wire (7875, A-M Systems), was inserted obliquely 3 mm into the arterial lumen distal to the flow probe. The needle was stabilized on either side of the vessel with 5-0 prolene sutures through the epicardium, and the silver wire was soldered to hookup wire (36F1727WA-9, Newark Electronics) sutured to the epicardium. A piece of 18-gauge wire that would be used to complete the electrical circuit was sutured to the intercostal muscles. Both the 18-gauge wire and the electrode and Doppler flow probe wires were tunneled subcutaneously and exteriorized dorsally. The chest was closed in layers and drained with a chest tube. Dogs were given a suspension of penicillin G benzathine and penicillin G procaine (0.1 mL/kg SC) daily for 3 days and buprenorphine (0.01 mg/kg IM) as needed for pain after surgery. Catheters were flushed daily with saline. Catheter dead space was filled with heparinized saline (100 U/mL).

Experimental Protocol
One week after surgery, dogs were sedated lightly with morphine sulfate (0.4 mg/kg IV followed by 0.2 mg/kg as needed for apparent discomfort) and placed in a supporting sling. The ECG and mean and phasic flow velocities in the instrumented coronary artery were monitored continuously. Thrombosis was induced by application of 300 µA of direct current through the coronary electrode connected in series with the positive terminal of a 9-V battery, an ammeter, a 20-k resistor, a 50-k potentiometer, and the implanted ground wire. Current was maintained until complete thrombotic occlusion had occurred, as reflected by zero flow velocity detected by the Doppler probe.

Complete occlusion was usually preceded by cyclic flow variations, consisting of gradual decreases in flow velocity followed by abrupt increases, analogous to flow variations attributable to intermittent accumulation and dislodgment of platelet thrombi as described previously.¹⁸

Beginning 1 hour after coronary occlusion (t=0), human recombinant tissue-type plasminogen activator (rTPA [Activase], Genentech, 1 mg/kg) was infused intravenously over a period of 60 minutes (Fig 1). Recanalization was defined as a return of mean flow velocity to at least 50% of the baseline value. After recanalization, blood flow velocity was monitored continuously for 24 hours to detect the occurrence of transitory or persistent reocclusion (defined as zero flow velocity persisting for at least 1 minute). In addition, the frequency of cyclic flow variations, defined as abrupt changes in average flow velocity (>5% from nadir to peak) was recorded. Before each study, dogs were randomly assigned to intravenous infusions of either of two doses of rTFPI (50 or 100 µg · kg^-1 · min^-1) or arginine-phosphate buffer as a control concomitantly with and continuing for 1 hour after infusion of rTPA.

View larger version (14K): [in this window] [in a new window]   Figure 1. Experimental protocol. *Intervals when blood samples were collected for assay of hematologic variables. t-PA indicates tissue-type plasminogen activator; rTFPI, recombinant tissue factor pathway inhibitor.

Hematologic Variables
As shown in Fig 1, blood samples were collected for determination of platelet counts, hematocrit, platelet aggregation, prothrombin time (PT), and activated partial thromboplastin time (aPTT) 45 minutes after the onset of persistent coronary occlusion (baseline) and 1 hour after completion of the infusion of rTPA, an interval during which virtually all exogenous rTPA is cleared from circulating blood in dogs. Platelets were counted with a hemocytometer and a phase-contrast microscope. Hematocrit was measured with a conductivity analyzer (Nova Biomedical). Platelet aggregation in platelet-rich plasma was assayed with bovine tendon collagen (Chronolog) as the agonist.¹⁹ The minimal concentration of collagen that elicited an irreversible increase in light transmission >50% in platelet-rich plasma was defined for each sample. aPTT and PT were assayed with a Coag-A-Mate XM automated coagulation timer (Organon Teknika). Buccal mucosal bleeding times were performed at the time of blood sampling as described by Jergens et al²⁰ with a Simplate II device (Organon Teknika).

Pharmacokinetic Analyses
In three additional conscious dogs, rTFPI was administered as an intravenous bolus (0.5 mg/kg) followed by serial blood sampling for assay of plasma levels of rTFPI. Data from each animal were analyzed by nonlinear regression²¹ and the modified Gauss-Newton method of residuals in which exponential terms are sequentially peeled off. Data from individual animals fit consistently to a biexponential of the form C=Ae^-at+Be^-bt, where C is the concentration of rTFPI at time t (minutes) and A and B are intercept values (t=0) extrapolated from a and b, the first-order elimination constants.

rTFPI in Plasma
Plasma rTFPI was measured by particle concentration fluorescence immunoassay as described previously.¹⁶ Plasma samples and rTFPI standards were diluted 1:20 in Tris-buffered saline containing 0.5 mol/L benzamidine, 0.1% BSA, and 1.0% polyoxyethylene ether (Lubrol, ICI). A 50-µL aliquot was incubated for 40 minutes at room temperature with 20 µL of a 0.25% suspension of 0.8-µm carboxylpolystyrene particles (Baxter Healthcare Corp) conjugated to anti–human TFPI IgG purified from rabbit serum on protein A-Sepharose 4B. Anti–human TFPI antibodies, further purified on a TFPI-Sepharose 4B column and labeled with FITC (isomer I, Sigma), were added (30 µL) and incubated for 30 minutes. Fluorescence was measured with a Pandex analyzer (Baxter). Sample rTFPI concentrations were calculated with reference to standards.

Statistical Analyses
Results are mean±SD. ANOVA for repeated measures was used to assess time-dependent changes in hemostatic variables. Fisher's exact test was used to compare incidences of reocclusion between groups. P.05 was considered to be significant.

	Results

Top Abstract Introduction Methods Results Discussion References

 
Among the 26 animals subjected to electrical vascular injury, 21 exhibited persistent thrombotic occlusion approximately 2 hours after the onset of electrical vascular injury (Table 1). All but 1 randomized to the high dose of rTFPI exhibited coronary recanalization after administration of rTPA. One animal randomized to low-dose rTFPI succumbed to hemorrhage into the chest. One animal randomized to high-dose rTFPI was not given the desired amount because of inadvertent precipitation of the agent in a contaminated perfusion catheter. Thus, data analyzed below came from 18 animals.

View this table: [in this window] [in a new window]   Table 1. Time to Induction of Initial Coronary Occlusion, Recanalization, and Reocclusion

Effect of Conjunctive rTFPI on Thrombolysis and Reocclusion
Conjunctive administration of rTFPI did not accelerate rTPA-induced recanalization, which occurred after an average of 41 and 38 minutes in animals given rTFPI and controls, respectively (Table 1). However, rTFPI exerted a dose-dependent reduction in the incidence of persistent reocclusion (Fig 2). All 6 of the vehicle-treated dogs exhibited reocclusion soon after completion of infusion of rTPA (Table 1, Fig 3). In contrast, reocclusion was delayed but occurred ultimately in 4 of 6 dogs given low-dose rTFPI and occurred in only 2 of 6 given the high dose (Table 1, Fig 3). The frequency of cyclic flow variations was decreased also in rTFPI-treated dogs (13±12/h with vehicle alone; 3±4/h with 50 µg · kg^-1 · min^-1 rTFPI, P=.09 compared with vehicle controls; and 2±2/h with 100 µg · kg^-1 · min^-1 rTFPI, P=.05 compared with controls). All the dogs, regardless of whether or not reocclusion occurred, exhibited patent arteries after 24 hours, with an average time to persistent recanalization of 8.8 hours (Fig 3), analogous to the spontaneous, late recanalization known to occur in patients regardless of treatment targeting an initial thrombus.

View larger version (27K): [in this window] [in a new window]   Figure 2. Bar graph showing effects of two concentrations of recombinant tissue factor pathway inhibitor (TFPI) or 300 mmol/L arginine-phosphate (Arg-Phos) vehicle administered together with and for 1 hour after discontinuation of the infusion of recombinant tissue-type plasminogen activator on the incidence of coronary reocclusion within 24 hours after initially successful fibrinolysis.

View larger version (19K): [in this window] [in a new window]   Figure 3. Bar graphs showing coronary patency in individual dogs given 300 mmol/L arginine-phosphate vehicle (arg-phos, top), 50 µg · kg-1 · min-1 recombinant tissue factor pathway inhibitor (TFPI, middle), or 100 µg · kg-1 · min-1 TFPI (bottom) during and for 1 hour after completion of the infusion of recombinant tissue-type plasminogen activator (tPA). Closed bars represent occluded arteries; open bars represent patent arteries. Intervals to sustained patency in dogs in which reocclusion occurred are shown to the right of the bars.

Hematologic Variables
Hematocrit was the same in rTFPI-treated and control dogs at baseline (41±5%, 40±4%, and 40±2% for 50 µg · kg^-1 · min^-1 rTFPI, 100 µg · kg^-1 · min^-1 rTFPI, and controls, respectively), and it was unchanged within 1 hour after completion of infusion of rTPA in all groups. Platelet counts were the same at baseline (average of 2.7x10⁸/mL) and also did not change appreciably. The minimal concentration of collagen required to induce irreversible aggregation of platelets assessed ex vivo was also unchanged (from 5.5±1.9 µg/mL at baseline to 6.5±1.9 µg/mL 1 hour after completion of infusion of rTPA in controls; from 5.6±3.0 to 6.4±3.3 µg/mL with low-dose rTFPI; and from 5.5±3.4 to 6.0±3.3 µg/mL with high-dose rTFPI).

High-dose rTFPI prolonged PT approximately twofold compared with baseline values (Table 2). aPTT increased proportionately less (Table 2). Bleeding time increased in both vehicle- and rTFPI-treated animals (Table 2), but spontaneous bleeding at sites of previous incisions did not occur.

View this table: [in this window] [in a new window]   Table 2. Coagulation Variables and Bleeding Time

Pharmacokinetics of rTFPI
Clearance of rTFPI from plasma after an intravenous bolus (0.5 mg/kg) was biexponential, with an -phase averaging 3 minutes (range, 2 to 6 minutes) and a ß-phase averaging 82 minutes (range, 32 to 163 minutes). On the basis of these data, dosages of rTFPI were selected to induce plasma levels between 2 and 5 µg/mL; the former was shown in our previous studies to inhibit reocclusion after fibrinolysis in femoral arteries of dogs.¹⁶

Plasma rTFPI values are shown in Fig 4. Maxima of 2.9 and 5.3 µg/mL occurred in animals given 50 and 100 µg · kg^-1 · min^-1 of rTFPI 60 minutes after initiation of infusions. After completion of infusions, plasma rTFPI returned rapidly toward baseline (Fig 4).

View larger version (21K): [in this window] [in a new window]   Figure 4. Graph showing plasma levels of recombinant tissue factor pathway inhibitor (TFPI) during and after completion of infusions.

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
Pharmacological fibrinolysis and the targeted coronary thrombus itself can activate coagulation.^{2 22 23 24 25} Thrombin has been regarded as the primary procoagulant involved.²⁶ Our results indicate that persistent activation of prothrombin mediated by factor Xa plays an important role. Conjunctive administration of rTFPI, which inhibits both activation of factor X mediated by the tissue factor/factor VIIa complex and previously activated factor X, elicited dose-dependent attenuation of reocclusion (Fig 2), decreased cyclic flow variations, and enhanced maintenance of patency over a 24-hour interval after administration of rTPA (Fig 3) without markedly perturbing hemostasis (Table 2) or platelet function.

Attenuation of reocclusion by rTFPI is likely to have been mediated primarily by its inhibitory effect on factor Xa bound to the residual thrombus. We have shown previously that factor Xa is the predominant procoagulant molecule associated with thrombus.⁹ Our present results are consistent with those reported by others²⁷ showing attenuation of reocclusion in dogs given recombinant tick anticoagulant peptide, a direct inhibitor of factor Xa, in combination with rTPA. A potential advantage of rTFPI is its inhibition of further activation of factors IX and X mediated by tissue factor, a constituent of adventitia,²⁸ subendothelium,²⁹ and atherosclerotic plaques²⁸ that when exposed to blood by vascular injury initiates thrombosis. Inhibition of tissue factor with monoclonal antibodies has been shown to attenuate thrombosis after arterial injury in experimental animals.^{30 31} Partial fibrinolysis may reexpose vascular tissue factor to blood. Furthermore, tissue factor can be expressed by injured vascular smooth muscle cells and activated monocytes ingressing into vascular lesions.^{32 33} Thus, tissue factor exposed or expressed during fibrinolysis may be inhibitable by rTFPI, contributing to the attenuation of reocclusion we observed.

We^{4 5} and others^{34 35 36} have shown that brief administration of potent direct inhibitors of thrombin in conjunction with fibrinolytic agents prevents reocclusion for 2 hours in dogs subjected to electrical arterial injury. It is not clear, however, whether brief administration of thrombin inhibitors alone would enhance patency, as is seen with rTFPI (Fig 3). They may be effective in maintaining patency only while they are administered or retained on thrombi during intervals when other procoagulant molecules such as factor Xa and the tissue factor/factor VIIa complex are being exposed to blood.

Inhibition of reocclusion was accomplished with plasma concentrations of rTFPI of 3 to 5 µg/mL (Fig 4), 150 to 200 times higher than endogenous concentrations in plasma under physiological conditions but comparable to concentrations in blood needed to enhance survival after E. coli–induced sepsis in baboons³⁷ and concentrations in solutions that prevent thrombotic occlusion after injury and microvascular repair of ear arteries in rabbits.³⁸

Because hemostasis and platelet function were not markedly affected and because the preparation we used is characterized by platelet-rich thrombi,⁴ effects of rTFPI on platelet aggregation in vivo were probably mediated through inhibition of thrombin generation.³⁹ Bleeding time was increased slightly in both rTFPI-treated and control animals (Table 2), probably because arginine in the buffer used led to elaboration of nitric oxide in peripheral vessels and inhibition of platelet adhesion⁴⁰ that may have potentiated bleeding in the assay.

Clinical Implications
Our results indicate that inhibition of activation of prothrombin is particularly effective in attenuating reocclusion after fibrinolysis. Furthermore, because of the lack of perturbation of hemostasis observed with rTFPI compared with inhibitors of thrombin,⁴ rTFPI may be particularly useful in conjunction with low doses of direct antithrombins and platelet inhibitors to prevent reocclusion without increasing the risk of bleeding.

	Acknowledgments

 
This study was supported in part by NIH grant HL-17646, SCOR in Vascular Diseases, and a Monsanto/Washington University Biomedical research grant. The authors thank Tze-Chein Wun, PhD, and Gerald Galluppi, PhD, at Monsanto/Searle for provision of rTFPI, Mark O. Palmier, PhD, at Monsanto for analyzing the rTFPI levels in blood samples, Pamela Baum for technical assistance, and Barbara Donnelly for preparation of the manuscript.

Received November 28, 1994; revision received February 9, 1995; accepted February 19, 1995.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. Sobel BE. Thrombolysis in the treatment of acute myocardial infarction. In: Fuster V, Verstraete M, eds. Thrombosis in Cardiovascular Disorders. Philadelphia, Pa: WB Saunders Co; 1992:289-326.
   
2. Abendschein DR. Relationships between suppression of coagulation and prevention of reocclusion. In: Sobel BE, Collen D, eds. Coronary Thrombolysis in Perspective: Principles Underlying Conjunctive and Adjunctive Therapy. New York, NY: Marcel Dekker; 1993:123-142.
   
3. Kaplan K, Davison R, Parker M, Mayberry B, Feiereisel P, Salinger M. Role of heparin after intravenous thrombolytic therapy for acute myocardial infarction. Am J Cardiol. 1987;59:241-244.[Medline] [Order article via Infotrieve]
   
4. Haskel EJ, Prager NA, Sobel BE, Abendschein DR. Relative efficacy of antithrombin compared with antiplatelet agents in accelerating coronary thrombolysis and preventing early reocclusion. Circulation. 1991;83:1048-1056. [Abstract/Free Full Text]
   
5. Prager NA, Torr-Brown SR, Sobel BE, Abendschein DR. Maintenance of patency after thrombolysis in stenotic coronary arteries requires combined inhibition of thrombin and platelets. J Am Coll Cardiol. 1993;22:296-301. [Abstract]
   
6. Cannon CP, McCabe CH, Henry TD, Schweiger MJ, Gibson RS, Mueller HS, Becker RC, Kleiman NS, Haugland JM, Anderson JL, Sharaf BL, Edwards SJ, Rogers WJ, Williams DO, Braunwald E. A pilot trial of recombinant desulfatohirudin compared with heparin in conjunction with tissue-type plasminogen activator and aspirin for acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) 5 trial. J Am Coll Cardiol. 1994;23:993-1003. [Abstract]
   
7. Lee LV. Initial experience with hirudin and streptokinase in acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) 6 trial. Am J Cardiol. 1995;75:7-13. [Medline] [Order article via Infotrieve]
   
8. Lidon RM, Theroux P, Lesperance J, Adelman B, Bonan R, Duval D, Levesque J. A pilot, early angiographic patency study using a direct thrombin inhibitor as adjunctive therapy to streptokinase in acute myocardial infarction. Circulation. 1994;89:1567-1572. [Abstract/Free Full Text]
   
9. Eisenberg PR, Siegel JE, Abendschein DR, Miletich JP. Importance of factor Xa in determining the procoagulant activity of whole-blood clots. J Clin Invest. 1993;91:1877-1883.
   
10. Broze GJ Jr, Warren LA, Novotny WF, Higuchi DA, Girard JJ, Miletich JP. The lipoprotein-associated coagulation inhibitor that inhibits the factor VII-tissue factor complex also inhibits factor Xa: insight into its possible mechanism of action. Blood. 1988;71:335-343. [Abstract/Free Full Text]
    
11. Broze GJ Jr. Tissue factor pathway inhibitor and the revised hypothesis of blood coagulation. Trends Cardiovasc Med. 1992;2:72-77.
    
12. Lindahl AK, Sandset PM, Abildgaard U. The present status of tissue factor pathway inhibitor. Blood Coagul Fibrinolysis. 1992;3:439-449. [Medline] [Order article via Infotrieve]
    
13. Girard TJ, Warren LA, Novotny WF, Likert KM, Brown SG, Miletich JP, Broze GJ. Functional significance of the Kunitz-type inhibitor domains of lipoprotein-associated coagulation inhibitor. Nature. 1989;338:518-520. [Medline] [Order article via Infotrieve]
    
14. Sandset PM, Abildgaard U, Larsen ML. Heparin induces release of extrinsic coagulation pathway inhibitor (EPI). Thromb Res. 1988;50:803-813. [Medline] [Order article via Infotrieve]
    
15. Novotny WF, Palmier M, Wun TC, Broze GJ, Miletich JP. Purification and properties of heparin releasable lipoprotein-associated inhibitor. Blood. 1991;78:394-400. [Abstract/Free Full Text]
    
16. Haskel EJ, Torr SR, Day KC, Palmier MO, Wun T-C, Sobel BE, Abendschein DR. Prevention of arterial reocclusion after thrombolysis with recombinant lipoprotein-associated coagulation inhibitor. Circulation. 1991;84:821-827. [Abstract/Free Full Text]
    
17. Diaz-Collier JA, Palmier MO, Kretzmer KK, Bishop BF, Combs RG, Obukowicz MG, Frazier RB, Bild GS, Joy WD, Hill SR, Duffin KL, Gustafson ME, Junger KD, Grabner RW, Galluppi GR, Wun T-C. Refold and characterization of recombinant tissue factor pathway inhibitor expressed in Escherichia coli. Thromb Haemost. 1994;71:339-346. [Medline] [Order article via Infotrieve]
    
18. Folts JD, Crowell EB Jr, Rowe GG. Platelet aggregation in partially obstructed vessels and its elimination with aspirin. Circulation. 1976;54:365-370. [Abstract/Free Full Text]
    
19. Haskel EJ, Adams SP, Feigen LP, Saffitz JE, Gorczynski RJ, Sobel BE, Abendschein DR. Prevention of reoccluding platelet-rich thrombi in canine femoral arteries with a novel peptide antagonist of platelet glycoprotein IIb/IIIa receptors. Circulation. 1989;80:1775-1782. [Abstract/Free Full Text]
    
20. Jergens AE, Turrentine MA, Kraus KH, Johnson GS. Buccal mucosa bleeding times of healthy dogs and of dogs in various pathologic states, including thrombocytopenia, uremia, and von Willebrand's disease. Am J Vet Res. 1987;48:1337-1342. [Medline] [Order article via Infotrieve]
    
21. Palmier MO, Hall LJ, Reisch CM, Baldwin MK, Wilson AGE, Wun T-C. Clearance of recombinant tissue factor pathway inhibitor (TFPI) in rabbits. Thromb Haemost. 1992;68:33-36. [Medline] [Order article via Infotrieve]
    
22. Eisenberg PR, Sherman L, Rich M, Schwartz D, Schechtman K, Geltman EM, Sobel BE, Jaffe AS. Importance of continued activation of thrombin reflected by fibrinopeptide A to the efficacy of thrombolysis. J Am Coll Cardiol. 1986;7:1255-1262. [Abstract]
    
23. Eisenberg PR, Sobel BE, Jaffe AS. Activation of prothrombin accompanying thrombolysis with recombinant tissue-type plasminogen activator. J Am Coll Cardiol. 1992;19:1065-1069. [Abstract]
    
24. Gulba DC, Barthels M, Westhoff-Bleck M, Jost S, Rafflenbeul W, Daniel WG, Hecker H, Lichtlen PR. Increased thrombin levels during thrombolytic therapy in acute myocardial infarction: relevance for the success of therapy. Circulation. 1991;83:937-944. [Abstract/Free Full Text]
    
25. Gash AK, Spann JF, Sherry S, Belber AR, Carabello BA, McDonough MT, Mann RH, McCann WD, Gault JH, Gentzler RD, Kent RL. Factors influencing reocclusion after coronary thrombolysis for acute myocardial infarction. Am J Cardiol. 1986;57:175-177. [Medline] [Order article via Infotrieve]
    
26. Weitz JI, Hudoba M, Massel D, Maraganore J, Hirsh J. Clot-bound thrombin is protected from inhibition by heparin-antithrombin III but is susceptible to inactivation by antithrombin III-independent inhibitors. J Clin Invest. 1990;86:385-391.
    
27. Sitko GR, Ramjit DR, Stabilito II, Lehman D, Lynch JJ, Vlasuk GP. Conjunctive enhancement of enzymatic thrombolysis and prevention of thrombotic reocclusion with the selective factor Xa inhibitor, tick anticoagulant peptide: comparison to hirudin and heparin in a canine model of acute coronary artery thrombosis. Circulation. 1992;85:805-815. [Abstract/Free Full Text]
    
28. Wilcox JN, Smith KM, Schwartz SM, Gordon D. Localization of tissue factor in the normal vessel wall and in the atherosclerotic plaque. Proc Natl Acad Sci U S A. 1989;86:2839-2843. [Abstract/Free Full Text]
    
29. Weiss HJ, Turitto VT, Baumgartner HR, Nemerson Y, Hoffmann T. Evidence for the presence of tissue factor activity on subendothelium. Blood. 1989;73:968-975. [Abstract/Free Full Text]
    
30. Jang I-K, Gold HK, Leinbach RC, Fallon JT, Collen D, Wilcox JN. Antithrombotic effect of a monoclonal antibody against tissue factor in a rabbit model of platelet-mediated arterial thrombosis. Arterioscler Thromb. 1992;12:948-954. [Abstract/Free Full Text]
    
31. Pawashe AB, Golino P, Ambrosio G, Migliaccio F, Ragni M, Pascucci I, Chiariello M, Bach R, Garen A, Konigsberg WK, Ezekowitz MD. A monoclonal antibody against rabbit tissue factor inhibits thrombus formation in stenotic injured rabbit carotid arteries. Circ Res. 1994;74:56-63. [Abstract/Free Full Text]
    
32. Taubman MB, Marmur JD, Rosenfield C-L, Guha A, Nichtberger S, Nemerson Y. Agonist-mediated tissue factor expression in cultured vascular smooth muscle cells: role of Ca²⁺ mobilization and protein kinase C activation. J Clin Invest. 1993;91:547-552.
    
33. Serneri GGN, Abbate R, Gori AM, Attanasio M, Martini F, Giusti B, Dabizzi P, Poggesi L, Modesti PA, Trotta F, Rostagno C, Boddi M, Gensini F. Transient intermittent lymphocyte activation is responsible for the instability of angina. Circulation. 1992;86:790-797. [Abstract/Free Full Text]
    
34. Yasuda T, Gold HK, Yaoita H, Leinbach RC, Guerrero JL, Jang I-K, Holt R, Fallon JT, Collen D. Comparative effects of aspirin, a synthetic thrombin inhibitor and a monoclonal antiplatelet glycoprotein IIb/IIIa antibody on coronary artery reperfusion, reocclusion and bleeding with recombinant tissue-type plasminogen activator in a canine preparation. J Am Coll Cardiol. 1990;16:714-722. [Abstract]
    
35. Yao S-K, Ober JC, Ferguson JJ, Anderson HV, Maraganore J, Buja LM, Willerson JT. Combination of inhibition of thrombin and blockade of thromboxane A₂ synthetase and receptors enhances thrombolysis and delays reocclusion in canine coronary arteries. Circulation. 1992;86:1993-1999. [Abstract/Free Full Text]
    
36. Rigel DF, Olson RW, Lappe RW. Comparison of hirudin and heparin as adjuncts to streptokinase thrombolysis in a canine model of coronary thrombosis. Circ Res. 1993;72:1091-1102. [Abstract/Free Full Text]
    
37. Creasey AA, Chang ACK, Feigen L, Wun T-C, Taylor FB Jr, Hinshaw LB. Tissue factor pathway inhibitor reduces mortality from Escherichia coli septic shock. J Clin Invest. 1993;91:2850-2860.
    
38. Khouri RK, Koudsi B, Faiding F, Ornberg RL, Wun T-C. Prevention of thrombosis by topical application of tissue factor pathway inhibitor in a rabbit model of vascular trauma. Ann Plast Surg. 1993;30:398-404. [Medline] [Order article via Infotrieve]
    
39. Torr SR, Eisenberg PR, Sobel BE. The dependence of activation of platelets by plasminogen activators on evolution of thrombin activity. Thromb Res. 1991;64:435-444. [Medline] [Order article via Infotrieve]
    
40. Moncada S, Palmer RMJ, Higgs EA. Nitric oxide: physiology, pathophysiology, and pharmacology. Pharmacol Rev. 1991;43:109-142.[Medline] [Order article via Infotrieve]
    

This article has been cited by other articles:

				Y. Zhao, S. Zhou, and C.-K. Heng Impact of Serum Amyloid A on Tissue Factor and Tissue Factor Pathway Inhibitor Expression and Activity in Endothelial Cells Arterioscler. Thromb. Vasc. Biol., July 1, 2007; 27(7): 1645 - 1650. [Abstract] [Full Text] [PDF]

				J. Steffel, T. F. Luscher, and F. C. Tanner Tissue Factor in Cardiovascular Diseases: Molecular Mechanisms and Clinical Implications Circulation, February 7, 2006; 113(5): 722 - 731. [Abstract] [Full Text] [PDF]

				A. H. M. Moons, R. J. G. Peters, N. R. Bijsterveld, J. J. Piek, M. H. Prins, G. P. Vlasuk, W. E. Rote, and H. R. Buller Recombinant nematode anticoagulant protein c2, an inhibitor of the tissue factor/factor VIIa complex, in patients undergoing elective coronary angioplastyAppendix J. Am. Coll. Cardiol., June 18, 2003; 41(12): 2147 - 2153. [Abstract] [Full Text] [PDF]

				A. H.M Moons, M. Levi, and R. J.G Peters Tissue factor and coronary artery disease Cardiovasc Res, February 1, 2002; 53(2): 313 - 325. [Abstract] [Full Text] [PDF]

				P. K. Shah Reduced Tissue Factor Pathway Inhibitor-1 After Pharmacological Thrombolysis: An Epiphenomenon or Potential Culprit in Rethrombosis? Circulation, January 22, 2002; 105(3): 270 - 271. [Full Text] [PDF]

				D. R. Abendschein, P. K. Baum, P. Verhallen, P. R. Eisenberg, M. E. Sullivan, and D. R. Light A Novel Synthetic Inhibitor of Factor Xa Decreases Early Reocclusion and Improves 24-h Patency after Coronary Fibrinolysis in Dogs J. Pharmacol. Exp. Ther., April 13, 2001; 296(2): 567 - 572. [Abstract] [Full Text]

				M. Roque, E. D. Reis, V. Fuster, A. Padurean, J. T. Fallon, M. B. Taubman, J. H. Chesebro, and J. J. Badimon Inhibition of tissue factor reduces thrombus formation and intimal hyperplasia after porcine coronary angioplasty J. Am. Coll. Cardiol., December 1, 2000; 36(7): 2303 - 2310. [Abstract] [Full Text] [PDF]

				J. J. Badimon, M. Lettino, V. Toschi, V. Fuster, M. Berrozpe, J. H. Chesebro, and L. Badimon Local Inhibition of Tissue Factor Reduces the Thrombogenicity of Disrupted Human Atherosclerotic Plaques : Effects of Tissue Factor Pathway Inhibitor on Plaque Thrombogenicity Under Flow Conditions Circulation, April 13, 1999; 99(14): 1780 - 1787. [Abstract] [Full Text] [PDF]

				L. Oltrona, C. M. Speidel, D. Recchia, S. A. Wickline, P. R. Eisenberg, and D. R. Abendschein Inhibition of Tissue Factor–Mediated Coagulation Markedly Attenuates Stenosis After Balloon-Induced Arterial Injury in Minipigs Circulation, July 15, 1997; 96(2): 646 - 652. [Abstract] [Full Text]

				C. R. McKenzie, D. R. Abendschein, and P. R. Eisenberg Sustained Inhibition of Whole-Blood Clot Procoagulant Activity by Inhibition of Thrombus-Associated Factor Xa Arterioscler. Thromb. Vasc. Biol., October 1, 1996; 16(10): 1285 - 1291. [Abstract] [Full Text]

				E. M. Antman Hirudin in Acute Myocardial Infarction: Thrombolysis and Thrombin Inhibition in Myocardial Infarction (TIMI) 9B Trial Circulation, September 1, 1996; 94(5): 911 - 921. [Abstract] [Full Text]

This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Abendschein, D. R. Articles by Sobel, B. E. Search for Related Content PubMed PubMed Citation Articles by Abendschein, D. R. Articles by Sobel, B. E.