Association Between Heparin Dose, Body Mass Index, and Stroke Risk in Patients Undergoing TAVR

Background: Unfractionated heparin (UFH) is routinely administered during transcatheter aortic valve replacement (TAVR) to prevent thromboembolic complications. However, there are no clear evidence-based guidelines defining optimal heparin dosing or target activated clotting time (ACT) values. This study aimed to evaluate the association between intraprocedural UFH dosing, ACT values, and peri-procedural stroke risk in the overall population of patients undergoing TAVR, with a prespecified stratified analysis according to body mass index (BMI ≥ 30 vs. <30 kg/m²). Methods: This analysis enrolled consecutive individuals with severe aortic stenosis (AS) who were treated with TAVR using either balloon-expandable or self-expanding valves. The primary outcome was the occurrence of stroke during the periprocedural period in the overall population and according to BMI (<30 vs. ≥30 kg/m²). Secondary endpoints included periprocedural parameters, clinical outcomes (in-hospital and 1-year mortality), and safety outcomes. Subgroup analysis was performed to assess stroke risk according to ACT values. Patients with atrial fibrillation or receiving chronic oral anticoagulation were excluded. Results: A total of 1045 patients underwent TAVR between 2022 and 2024, including 827 with BMI < 30 and 218 with BMI ≥ 30. The study population had a mean age of 82 ± 6 years, and 56% of patients were male. In the overall study population, the mean heparin dose was 47 U/kg and the mean ACT value was 218 s. Patients with lower BMI received higher heparin doses (50 vs. 40 U/kg, p < 0.01) and had higher ACT values (221 vs. 208 s, p < 0.01). Protamine use was low and similar between groups. Periprocedural stroke rates were low overall (1.1%) and comparable between study groups (1.2% vs. 0.9%, p = 0.71). One-year mortality was also similar (3% vs. 4%, p = 0.53), with no significant differences in other safety outcomes. Subgroup analysis by ACT (≤250 vs. >250 s) showed no difference in stroke rates (1% vs. 1.5%, p = 0.60). Conclusions: In this single-center cohort, differences in heparin dosing and ACT values were not associated with differences in peri-procedural stroke or overall procedural outcomes. However, given the low number of stroke events, these findings should be interpreted cautiously. Prospective randomized studies are needed to define optimal anticoagulation strategies during TAVR.