Why heparin?

[mshow00]

A question to the doctors here (or anyone who may know the real answer): My partner and I just finished a transport to SLU hospital from a local Metro East hospital of a 44 yo male with a blocked(or severely reduced) arterial block in his right leg. He and his wife are OTR truck drivers. Anyway, the pick-up hospital had him on a heparin drip(through a pump) and I was wondering why heparin, I mean would not tPA(or other clot buster) be the better choice to restore blood flow to the leg? I have only minimal very minimal knowledge of these medications and just looking for some knowledgeable input.

[Kaisu]

The clot in the leg is already there and you don't want to do ANYTHING to dislodge it. The last thing you want is that clot moving and going into the lung. The heparin is to prevent further clot formation.

[AZCEP]

tPA will destroy all the clots that have formed indiscriminately. You don't know if there are any "good" clots present or not, so let's not just eliminate all of them.

Heparin reduces the formation of new clots, but does not break established clots down.

[mshow00]

Even at the risk of the pt loosing part/all of his leg due to the restricted blood flow?

With that SLU had a vascular surgeon in the ED room 30 seconds after we walked in starting his test and prepping the pt for emergancy surgery later tonight. So I doubt greatly that he will loose the leg, but under principal?

[AnthonyM83]

Think about how much damage a pulmonary embolism or stroke might do compared to a severed leg, though (possible consequences if the clot broke free). Instead of putting him at risk for that, why not just have him go into surgery to fix the leg.

[Kaisu]

Skeletal muscle can go hours (as much as 6 to 8) without O2 and not sustain permanent damage. 4 - 6 minutes without oxygen will cause the neo-cortex to start to die.

[ERDoc]

This was an arterial clot, so you do not need to worry about a PE or stroke. You need to worry about distal occlusion if a piece breaks off. Heparin is to prevent the clot from getting worse. The vascular surgeon can administer intraarterial tPA at a much lower dose than it were just administered through an IV. It is safer for the pt this way as they are at much less risk for bleeding. Also, depending on where the clot is they can pull part of the clot out (oversimplifcation here). In someone who is going to be undergoing a surgical procedure, the last thing you want to do is take away their ability to clot.

[Mateo_1387]

He has an arterial clot in his leg, how would that go to his lungs or brain? I would think that he lucked out that it did not go to his brain.

[logos]

I think the potential morbidity of tPA is often underestimated. The benefit in stroke, which itself is incredibly morbid, is very small. This is why the criteria for IV tTPA are so stringent (severe deficits, known start time <3 hrs, reasonable BP, etc), as it is only those who meet the criteria that have been shown to benefit from the tPA enough to statistically overcome the morbidity of the drug.

[Kaisu]

oops - me bad... I read DVT - Nonetheless, tPA in stroke is nowhere near as effective as when used in ACS. The outcome works out roughly in thirds - one third get better, one third have no change and one third DIE. I think if I was having a mild stroke I'd waive the tPA - on the other hand, if my stroke was a big one I would probably have it - for an arterial blockage of the leg - no way.