Abstract
Severe hypotention occurred twice immediately after protamine administration in a patient who underwent coronary artery bypass graft surgery. The cause of the first hypotensive episode is not clear, but that of the second crisis was thought to be due to the spasm which occurred in the left main coronary artery. The coronary artery is said to be susceptible to spasms after extracorporeal circulation, which was the case with this patient.
Protamine or protamine-heparin interaction increases the plasma level of C3a and C5a, which are products of complement activation, after its administration. These two compounds induce vasospasm, increase vascular permeability and contract smooth muscles. Thus, protamine administration may have played a role in the coronary artery spasm that occurred in this patient.
After the second crisis, protamine was not administered to reverse heparin. The postoperative course was uneventful and bleeding was controlled well.
Authors suggest that, though there is a risk of postoperative bleeding, heparin may not need to be reversed in a similar situation.
