while the specification concludes with claims particularly pointing out and distinctly claiming the subject matter regarded as forming the invention , it is believed that the invention will be better understood from the following detailed description of illustrative embodiments of the invention taken in conjunction with the accompanying drawings . fig1 is a bar graph which shows the maximal neointimal thickness in μm four weeks after arterial intervention for balloon angioplasty and intimectomy with tfpi treatment ( 40 μg / ml in pbs ) vs untreated control ( pbs ). fig2 is a sketch of one embodiment of the method of the invention for delivery of tfpi to the site of the vascular injury in which the arterial intervention is a balloon angioplasty . fig3 is a sketch of another embodiment of the method of the invention for delivery of tfpi to the site of the vascular injury in which the arterial intervention is a vascular anastomosis . in order to illustrate the invention in greater detail , the following illustrative examples were carried out on laboratory rabbits : the tfpi used in these examples was obtained through recombinant dna clones expressed in e . coli . it is a 277 - amino acid protein consisting of the 276 - residus sequence described by wun et al ., j . biol chem . 263 , 6001 - 6004 ( 1988 ), and in u . s . pat . no . 4 , 966 , 852 , with a trivial modification whereby an additional alanine residue was inserted at the n - terminus as described in u . s . pat . no . 5 , 212 , 091 . in sixteen ( 16 ) adult nzw rabbits in these examples , the left common carotid artery was subjected to a balloon angioplasty ; the right common carotid to an intimectomy and vascular anastomosis . before restoring blood flow the vessels were irrigated with either 1 ml of control buffer or tfpi ( 40 μg / ml ). with an elastin stain , maximal neointimal thickness was measured at both two and four weeks ( n = 4 for each group at each time point for each procedure ). in eight additional rabbits , platelet deposition and the local persistence of gold - labeled tfpi ( tfpi *) following a vascular anastomosis were followed by electron microscopy ( em ) at 10 &# 39 ; ( min .) 24 hours , 72 hrs , and one week ( n = 2 at each time point ). there was no significant intimal hyperplasia at two weeks in either group following any of the procedures . at four weeks , the maximal neointimal thickness in control vessels injured by balloon angioplasty was 92 . 20 ± 28 . 60 μm . treatment with tfpi reduced the maximal lesion thickness 36 . 85 ± 16 . 46 μm . in the intimectomized vessels at four weeks , the maximal neointimal thickness in control buffer - treated vessels was 84 . 83 ± 23 . 94 μm . local application with tfpi decreased the maximal neointimal thickness to 51 . 23 ± 18 . 52 μm . compared to control , all ems during the first week showed lack of platelet aggregation and thrombus formation at the intimal surface and a persistence with a gradual decrease in the amount of tfpi * specifically bound to immature fibrin strands . the national institutes of health &# 34 ; guide for the care and use of laboratory animals &# 34 ; ( publication no . 86 - 23 , revised 1985 ) was followed throughout these examples . adult new zealand white rabbits ( 3 . 5 - 4 kg ) were used in all experiments . anesthesia was induced with an intramuscular injection of ketamine ( 15 mg / kg ) and xylazine ( 5 mg / kg ). all surgical procedures were carried out under sterile conditions . balloon angioplasty . in sixteen ( 16 ) rabbits , a 2 cm segment of the right common carotid artery was exposed and isolated with a proximal and distal vascular clamp . a 2fr . embolectomy catheter was inserted via an arteriotomy . the balloon was inflated and withdrawn three times , rotating the catheter 120 degrees after each pass to ensure uniform injury ( 48 ). the catheter was then removed and the arteriotomy site repaired . prior to removing the clamps and restoring blood flow , the lumen was irrigated with 1 cc of either ( a ) control buffer ( 5 mm phosphate buffer ) in eight ( 8 ) rabbits , or ( b ) tfpi ( 40 μg / ml ) in the other eight ( 8 ) rabbits in a randomized and blinded fashion . intimactomy / vascular anastomosis . in the same sixteen ( 16 ) rabbits , the left common carotid artery was exposed and subjected to an intimectomy and a vascular anastomosis . the 3 cm segment of the artery was isolated with a proximal and distal vascular clamp . the artery was transected and the distal and everted . using a microsurgical blade , 1 cm of intima was scraped off over 25 % of the vessels circumference . the vessel was reverted and anastomosed using standard technique . before placing the last stitch and restoring blood flow , 1 cc of control buffer - tfpi ( 40 μg / ml ) was irrigated within the lumen . evaluation of intimal hyperplasia . animals were sacrificed at both two and four weeks , and the vessels were harvested following perfusion fixation at physiologic pressure with 10 % buffered formalin ( n = 4 for each group at both time points for each type of injury ). the vessels were embedded , and serial transverse sections were stained with a modified verhoeff van gieson stain to visualize the elastin and delineate the junction between the intima and media . the point of maximal neointimal thickness was then measured using computerized image analysis . tfpi - binding and electron microscopy . in eight additional rabbits , the central ear artery was transected and anastomosed . prior to restoring blood flow , the lumen gas irrigated with 1 ml of unconjugated gold particles or gold - labeled tfpi ( tfpi *). the gold label was for enhancement of the electron microscopy . the vessels were harvested at 10 minutes , 24 hrs , 72 hrs , and one week , and fixed for electron microscopy ( 4 % glutaraldehyde in 20 mm heipes - buffered hank &# 39 ; s saline , ph 7 . 35 - 7 . 4 ). the amount of platelet deposition and the local persistence of tfpi * were evaluated by em ( n = 2 at each time point ). balloon angioplasty . there was no significant intimal hyperplasia at two weeks in either group . at four weeks , the maximal neointimal thickness in vessels injured by balloon angioplasty and treated with phosphate buffer was 92 . 20 ± 28 . 06 μm . treatment with tfpi reduced the maximal lesion thickness 36 . 83 ± 16 . 46 μm . intimectomy . at two weeks , there was no significant intimal hyperplasia in either group at four weeks , the maximal neointimal thickness in phosphate buffer - treated vessels was 84 . 83 ± 23 . 94μm . local application with tfpi decreased the maximal neointimal thickness to 51 . 23 ± 18 . 52 μm . tfpi - binding and electron microscopy . ems of vessels treated with unconjugated gold particles showed numerous platelets adherent to the exposed elastic lamina and stands of fibrin clot within ten ( 10 ) minutes after injury . all ems of vessels treated with gold - labeled tfpi during the first week showed lack of platelet aggregation and thrombus formation at the intimal surface , and a persistence with a gradual decrease in the amount of tfpi * specifically bound to immature fibrin strands . topical administration of the tfpi can be carried out by conventional methods of administration of topically effective drugs which are well known to persons skilled in the art . the tfpi is preferably administered from admixture with a physiologically acceptable vehicle or carrier , e . g , normal saline or buffered saline , such as phosphate - buffered saline or other such pharmaceutically acceptable buffers , e . g ., hepes and the like . the tfpi can also be administered in powder , salve or ointment form in conventional pharmaceutically acceptable vehicles . such conventional vehicles and carriers are well known to the person skilled in the art , as can be seen by reference to numerous texts and treatises in the field of drug administration , e . g ., remington &# 39 ; s pharmaceutical sciences , ed . arthur osol , 16th ed ., 1980 , mack publishing co ., easton , pa ., or 18th ed ., 1990 . the amount of tfpi administered acutely and topically at the site and time of vascular injury can be a very small amount , depending in part on the degree and extent of the injury . doses of tfpi of from about 1 μg / ml to about 100 μg / ml in a volume of about 0 . 01 ml to about 1 ml applied at the injured site are suitable . it should be understood , however , that in some instances it may be desirable to administer a second dose , or to apply a sustained delivery of the tfpi for better inhibition of the intimal hyperplasia , although the inventors are not bound by this suggestion . the administration of tfpi according to the method of the invention is further illustrated by the two procedures shown in fig2 and 3 . when the arterial intervention procedure is performed percutaneously , then a catheter device similar to that shown in fig2 is preferably used for delivery of the tfpi ; whereas , when the arterial intervention procedure is performed openly with exposure of the vessel , then a catheter device similar to that shown in fig3 is preferably used for delivery of the tfpi . in fig2 a portion of the clogged artery is shown in which the procedure involves use of a four - fold catheter device . a distal occluding balloon and a proximal occluding balloon are used to isolate this portion of the artery and the clogged artery is subjected to the angioplasty balloon . a fourth catheter is shown for delivery of the tfpi through a larger port and / or smaller ports positioned along the length of the catheter . in fig3 a portion of the clogged artery is shown in which the procedure consists of a vascular anastomosis such as , e . g ., bypass graft or endarterectomy . a catheter is shown for irrigating the lumen of the vessel at the site of the vascular injury by delivery of the tfpi prior to restoration of blood flow . various other examples will be apparent to the person skilled in the art after reading the present disclosure without departing from the spirit and scope of the invention . it will be understood that all such other examples are included within the scope of the appended claims . 1 . califf , r m , fortan , d f , frid , d j , et al . restenosis after coronay angioplasty : an overview . j am coll cardiol 17 : 2b - 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a method is disclosed for inhibiting intimal hyperplasia in a warm - blooded mammal which comprises administering topically at the site and time of a vascular injury induced by arterial intervention in said mammal a small but inhibitorily effective amount of tissue factor pathway inhibitor sufficient to inhibit said intimal hyperplasia .