The results of a US national survey on the use of antiplatelet medications and protamine during carotid interventions were presented by Ross Milner, Loyola University Medical Center, Maywood, USA, at the Society for Clinical Vascular Surgery meeting in Orlando, USA.
“The use of anticoagulation during carotid endarterectomy and carotid artery stenting has been standard practice for many years. However, reversal with protamine sulfate has not been a formally standardised process,” Milner said. “In our study, we assessed the anticoagulation therapies most commonly used before, during, and after these procedures. In addition, the investigators also evaluated the percentage of vascular surgeons who perform carotid artery interventions.”
A paper by David H Stone et al showed that protamine reduces bleeding complications associated with carotid endarterectomy without increasing the risk of stroke (J Vasc Surg 2010;51:559–64), Milner noted. The study concluded that “Protamine reduced serious bleeding requiring re-operation during carotid endarterectomy without increasing the risk of myocardial infarction, stroke, or death, in this large, contemporary registry. In light of significant complications referable to bleeding, liberal use of protamine during carotid endarterectomy appears warranted.
In Milner and Elizabeth M Quiroz’s work, members of the Society for Vascular Surgery were sent an email survey via Survey Monkey with 16 multiple choice questions about carotid endarterectomy and stenting anticoagulation management. The questions addressed the choices of antiplatelet therapy prior to the procedure, assessment of platelet inhibition prior to the procedure, anticoagulation therapy during the procedure, and the use of protamine. The results were then analysed and used for comparison between the use of these medications for carotid endarterectomy versus stenting.
A total of 2,434 recipients were sent a questionnaire and 654 (27%) participated in the survey. Of these 654 participants, 649 (99%) stated that they perform carotid endarterectomy and 571 (87.3%) perform carotid artery stent placement.
Of the 649 vascular surgeons that perform carotid endarterectomy, 84.5% use Aspirin alone pre-operatively. Plavix was used by 4.2% and both were used by 9.7%. Ninety nine per cent use heparin during the procedure and 48.6% use protamine to reverse the heparin dose.
Of the 571 vascular surgeons that perform stenting, only 40.9% use a combination of Aspirin and Plavix before the procedure. Aspirin alone was used by 26.7% and Plavix alone by 45.4%. Ninety three per cent use heparin during the procedure (6.2% used Bivalirudin), and only 16.6% reversed the heparin dose with protamine.
Only 3.5% of the respondents said they assess platelet inhibition prior to carotid endarterectomy and 3.9% before carotid stenting. “This shows we do not assess platelet inhibition,” Milner said.
The results, Milner stated, show that antiplatelet use differs between carotid endarterectomy and stenting. The survey, he added, showed that activated clotting time is more commonly used for stenting, and that heparin dose and activated clotting time are higher for stenting.
In terms of reversion with protamine, the survey showed that approximately 50% reverse with protamine after endarterectomy and 20% reverse based on activated clotting time values after endarterectomy. Twenty per cent reverse with protamine after stenting, and over 30% reverse based on activated clotting time values after stenting.
“There is a substantial difference in the selection of antiplatelet medications before the two procedures. In addition, there is a large difference in the administration of protamine after carotid endarterectomy as compared to stenting. This survey suggests that there is no standard practice on the use of pre-procedure medications or the use of protamine sulfate for heparin reversal during carotid procedures,” Milner concluded.