Defining the Optimal Degree of Heparin Anticoagulation for Peripheral Vascular Interventions

BACKGROUND: The optimal degree of heparin anticoagulation for peripheral vascular interventions (PVIs) has not been defined. We sought to correlate total heparin dose and peak procedural activated clotting time (ACT) with postprocedural outcomes in patients undergoing PVI. METHODS AND RESULTS: We studied 4743 patients who received heparin during PVIs in a regional, multicenter registry. From those, 1246 had recorded peak procedural ACT with the same point-of-care device. Periprocedural and in-hospital outcomes were compared between patients who received a total heparin dose <60 U/kg (n=2161) and ≥60 U/kg (n=2582). Similarly, outcomes were evaluated between groups with a peak procedural ACT <250 seconds (n=855) and ≥250 seconds (n=391). Technical and procedural success as well as intraprocedural thrombotic events did not differ between groups. Patients with heparin dose ≥60 U/kg had a higher rate of postprocedural hemoglobin drop ≥3 g/dL (7.09% versus 5.09%, respectively, P=0.004) and a higher transfusion rate compared with those with heparin dose <60 U/kg (4.92% versus 3.15%, respectively, P=0.002). In multivariate analysis, independent predictors of bleeding requiring transfusion were total heparin dose ≥60 U/kg, ACT ≥250 seconds, female sex, age ≥70 years, prior anemia, prior heart failure, low creatinine clearance, hybrid vascular surgery, rest pain, and below-knee intervention. In propensity-matched, risk-adjusted models and after hierarchical modeling, total heparin dose ≥60 U/kg and ACT ≥250 seconds remained strong predictors of post-PVI drop in hemoglobin ≥3 g/dL or transfusion. CONCLUSIONS: During PVI, higher total heparin dose (≥60 U/kg) and peak ACT ≥250 seconds were predictors of postprocedural transfusion. The high technical and procedural success in all groups suggests that use of weight-based heparin dosing with a target ACT <250 seconds in PVI may minimize the bleeding risk without compromising procedural success or increasing thromboembolic complications.