Is heparin reversal with protamine after carotid endarterectomy dangerous?

Abstract

Objective: Although systemic heparinisation is routine during CEA, reversal with protamine is controversial with 3 studies suggesting increased peri-operative stroke rates and 3 no effect. None included independent peer-review.

Design: Non-randomised observational study of data derived from a randomised controlled study of anaesthetic technique for CEA.

Methods: Data on heparin and protamine use and risk factors potentially influencing CEA outcome were collected prospectively. Stroke, death, MI, wound haematoma and re-operation rates were recorded following independent peer-review.

Results: 1513/2107 patients received heparin alone (H) and 594/2107 had heparin reversed with protamine (H+P). Risk factors for outcome were similar in both groups. The frequency of outcome events (H v H+P) were: stroke: 67/1513 (4.4%) v 17/594 (2.9%), p=0.098; non stroke or MI death: 10/1513 (0.7%) v 5/594 (0.8%), p=0.657; MI: 6/1513 (0.4%) v 3/594 (0.5%), p=0.718; haematoma: 157/1513 (10.4%) v 44/594 (7.4%), p=0.037; re-operation: 51/1380 (3.7%) v 18/565 (3.2%), p=0.581.

Conclusions: These results show a non-significant increase in stroke rate in patients receiving heparin alone refuting suggestions that protamine is harmful. Conversely post-operative haematoma was more frequent when protamine was withheld but re-operation rates were no different. Thus protamine use appears safe and should remain a matter for individual surgeon preference.