Evaluation of a novel standardized protocol for nurse-guided heparin dosage during left atrial ablation procedures

Background: Current guidelines recommend intraprocedural administration of unfractionated heparin targeting an activated clotting time (ACT) >300 s for left atrial ablation procedures.

Aims: To evaluate a novel standardized heparinization protocol in a prospective patient cohort undergoing left atrial ablation procedures in terms of effectivity of intraprocedural anticoagulation and patient safety.

Methods: Consecutive patients undergoing left atrial catheter ablation for AF or left atrial tachycardia (LAT) between 05/2022 and 05/2023 were prospectively enrolled. A novel institutional standardized heparinization protocol was implemented in the study group. Patients who underwent AF or LAT ablation between 05/2021 and 04/2022 without the use of a standardized heparin protocol served as a control group. Patients in both groups received initially 5000 I.U. of heparin after groin puncture. After transseptal puncture, patients in the study group received for each ten kilograms above a bodyweight of 50 kilograms further 1000 I.U. of heparin. ACT measurements were then conducted every 20 minutes in both groups. In cases of ACT values <300s further heparin was administered following the standardized institutional protocol based on body weight and ACT in the study group autonomously by nurses. Patients in the control group received further heparin based on the operator’s discretion. The primary endpoint was defined as at least one documented ACT >300s.

Results: A total of 655 patients (218 females, 33.2%) with a mean age of 65.2±11.0 years and a mean BMI of 28.7±5.5 kg/m² were included into the study group. Median CHA₂DS₂-VASC score was 2 {1;3} and median HAS-BLED score 1 {1;2}. The control group consisted of 655 patients and there were no statistically significant differences with regards to baseline characteristics among patient cohorts (table 1). Radiofrequency-based PVI or left atrial ablation was performed in 313 (52.7%) patients, cryoballoon PVI in 154 (25.9%) patients and pulsed field ablation in 128 (21.5%) patients. Detailed procedural data is shown in table 2 for both groups. The primary endpoint occurred significantly more often in the study group (554 patients (84.6%) vs. 391 patients (59.6, p<0.0001). Periprocedural complications occurred in 12 patients of the study group (1.8%): 3 AV fistulas (0.5%), 3 pseudoaneurysms (0.5%), three pericardial tamponades (0.5%) and 3 periprocedural transitoric ischemic attack or strokes (0.5%). Notably, the three patients who experienced TIA/stroke had an effective ACT>300s at the end of the procedure. Complication rates in the control group were similar with no significantly difference in occurrence of transitoric ischemic attacks or strokes.

Conclusions: Implementing a consistent heparinization protocol led to a significantly higher rate of patients reaching at least one intraprocedural ACT >300s during left atrial ablation procedures. Furthermore, a protocol that nurses can follow independently may simplify intraprocedural ACT management for the operator.