PURPOSE: To compare in an animal model of deep vein thrombosis, an intramur
al drug delivery catheter, the nipple-balloon catheter, with an occlusion b
alloon-infusion guide wire system,
MATERIALS AND METHODS: Ten juvenile pigs were used for the study. Deep vein
thrombosis was induced in both hind limbs by using a previously described
technique. Heparin was administered 30 minutes later (2,500 IU intravenousl
y) and bilateral thrombolysis was attempted with use of 8 mg of alteplase a
s a 0.25 mg/mL solution containing heparin 50 IU/mL (n = 10) and sodium/meg
lumine ioxaglate 40 mgI2/mL (n = 5), In one limb, the external iliac vein w
as endoluminally occluded, and 0.8 mL of alteplase was administered every 3
minutes through a multisideport infusion wire placed coaxially through the
balloon catheter, On the other side, a nipple-balloon catheter was used: a
lteplase was injected as two 0.4-mL aliquots every 3 minutes in overlapping
segments of the vessel, flood samples were taken at predetermined interval
s to determine the partial thromboplastin time and plasma fibrinogen concen
tration. At autopsy, the thrombus mass in the iliofemoral veins was measure
d, and the extent of residual thrombosis in the venous tributaries was grad
ed at four sites. The heart and the lungs were also examined for thromboemb
oli (n = 5), Venous specimens were then subjected to X-ray fluorescence spe
ctrometry to determine iodine content (n = 5),
RESULTS: Bilateral thrombolysis could be successfully completed in all anim
als. No procedural problem associated with the use of the nipple-balloon ca
theter was encountered, The mass of residual thrombus in the axial veins wa
s significantly lower in this group (P = .005), The drug delivery system us
ed did not appreciably influence thrombolysis in the tributaries. Signs of
macroscopic damage to the veins were not observed in any animal. None of th
e venous specimens had detectable levels of iodine. Small thromboemboli wer
e found in the pulmonary circulation in three of five animals, Fibrinogen l
evels did not decrease during the procedure,
CONCLUSIONS: The significantly lower residual thrombus burden associated wi
th use of the nipple-balloon catheter suggests that the device may have the
potential to be an effective delivery system for selective thrombolysis in
veins.