Protamine

Comparative studies

In a prospective study of patients undergoing cardiopulmonary bypass, 11% of patients receiving protamine sulfate had adverse reactions of varying types [ ].

In a double-blind, randomized trial, 167 patients undergoing aortocoronary bypass graft surgery received either heparinase I (maximum 35 micrograms/kg) or protamine (maximum 650 mg) for heparin reversal [ ]. Although the two treatments had similar efficacy, protamine had a better adverse reactions profile. Those given heparinase I had longer hospital stays, were more likely to have a serious adverse event, and were less likely to avoid transfusion. A composite morbidity score was not different, and there were similar rates of hemodynamic instability.

The concern that heparin reversal by protamine after carotid endarterectomy might increase the risk of thrombotic strokes has been studied in an unrandomized observational analysis of data derived from a randomized controlled study of anesthetic technique for carotid endarterectomy in 2107 patients, of whom 1513 received heparin alone and 594 had reversal with protamine [ ]. The respective frequencies of the outcome events were: stroke—67/1513 (4.4%) versus 17/594 (2.9%); non-stroke or myocardial infarction death—10/1513 (0.7%) versus 5/594 (0.8%); myocardial infarction—6/1513 (0.4%) versus 3/594 (0.5%); hematoma—157/1513 (10%) versus 44/594 (7.4%); re-operation—51/1380 (3.7%) versus 18/565 (3.2%). Of these, only postoperative hematoma was more frequent when protamine was not used to reverse heparin.