Heparin reversal with protamine tied to lower rate of bleeding after carotid endarterectomy

By Will Boggs MD

NEW YORK (Reuters Health) - Giving protamine sulfate after carotid endarterectomy (CEA) to reverse the anticoagulant effect of heparin is associated with a reduction in bleeding complications without increased thrombotic risk, according to a meta-analysis of observational studies.

"I hope surgeons come away from this study reassured that protamine does not increase the risk of stroke after CEA," Dr. Karina A. Newhall from Dartmouth Hitchcock Medical Center in Lebanon, New Hampshire, told Reuters Health by email. "With that concern addressed, the choice to use protamine to reverse heparin becomes easier because it decreases the risk for reoperation and all its associated morbidities."

Surgeons routinely administer heparin to reduce thrombus formation during arterial clamping, whereas heparin reversal practices vary widely, with studies reporting rates of protamine use ranging from less than 20% to 100% of surgeons, Dr. Newhall and colleagues write in JAMA Surgery, online October 21.

The team performed a meta-analysis of 12 observational studies that examined stroke and bleeding in relation to protamine use after CEA. The rates of perioperative stroke did not differ significantly between patients who received protamine (1.59%) and those who did not receive protamine (2.02%) after CEA, they report.

In contrast, patients treated with protamine were 48% less likely than patients not treated with protamine to experience major bleeding and 54% less likely to experience any bleeding events after CEA.

All-cause mortality did not differ significantly between patients who received protamine (1.2%) and patients who did not (1.7%).

"One of the other interesting things we found is that the overall stroke risk after CEA had decreased pretty dramatically over time as we continue to learn better preoperative care and better surgical techniques," Dr. Newhall said. "Obviously, this is a great thing for patients undergoing the procedure."

"As I read the guidelines, they tend to issue official recommendations based on randomized trial evidence," Dr. Newhall cautioned. "Our meta-analysis used largely observational evidence, so I would hesitate to issue definitive guidelines on what should be the standard of care in CEA."

Dr. Enzo Ballotta from the University of Padua School of Medicine in Padova, Italy, who coauthored an invited commentary on the report, has fewer reservations. He told Reuters Health by email, "On the basis of the results of several studies (including ours) and the meta-analysis, we believe there is enough evidence to promote a change in the guidelines."

SOURCE: http://bit.ly/1kQoj29 and http://bit.ly/1PTOCQH

JAMA Surg 2015.

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