Recent studies have found that transcarotid artery revascularization (TCAR) is associated with lower risk of stroke or death compared with transfemoral carotid artery stenting but higher risk of bleeding complications, presumably associated with the need for an incision. Heparin anticoagulation is universally used during TCAR, so protamine use may reduce bleeding complications. However, the safety and effectiveness of protamine use in TCAR are unknown. We therefore evaluated the impact of protamine use on perioperative outcomes after TCAR in the Vascular Quality Initiative TCAR Surveillance Project.
We performed a retrospective review of patients undergoing TCAR in the Vascular Quality Initiative TCAR Surveillance Project from September 2016 to April 2019. We assessed in-hospital outcomes using propensity score-matched cohorts of patients who did and did not receive protamine. The primary efficacy end point was access site bleeding complications, and the primary safety end point was in-hospital stroke or death. Secondary end points included the individual end points of stroke, death, transient ischemic attack, myocardial infarction, congestive heart failure exacerbation, and hemodynamic instability.
Of the 5144 patients undergoing TCAR, all patients received heparin and 4072 (79%) patients received protamine. We identified 944 matched pairs of patients who did and did not receive protamine. Protamine use was associated with a significantly lower risk of bleeding complications (2.8% vs 8.3%; relative risk [RR], 0.33; 95% confidence interval [CI], 0.21-0.52; P < .001), including bleeding that resulted in interventional treatment (1.0% vs 3.6%; RR, 0.26; 95% CI, 0.13-0.54; P < .001) and in blood transfusion (1.2% vs 3.9%; RR, 0.30; 95% CI, 0.15-0.58; P <.001). There were no statistically significant differences in in-hospital stroke or death for patients who received protamine and those who did not (1.6% vs 2.2%; RR, 0.71; 95% CI, 0.37-1.39; P = .32); however, there was a trend toward lower risk of stroke for patients who received protamine (1.1% vs 2.0%; RR, 0.53; 95% CI, 0.24-1.13; P = .09). There were also no statistically significant differences in the rates of transient ischemic attack (0.4% vs 1.1%; RR, 0.40; 95% CI, 0.13-1.28; P = .11), myocardial infarction (0.4% vs 0.8%; RR, 0.50; 95% CI, 0.15-1.66; P = .25), heart failure exacerbation (0.4% vs 0.3%; RR, 1.33; 95% CI, 0.30-5.96; P = .71), or postoperative hypotensive hemodynamic instability (16% vs 15%; RR, 1.06; 95% CI, 0.83-1.35; P = .50) with protamine use.
Protamine can be safely used in TCAR to reduce the risk of perioperative bleeding complications without increasing the risk of thrombotic events.

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