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Updated: Jul 5, 2025
The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
Evaluation of an adaptive, rule-based dosing algorithm to maintain therapeutic anticoagulation during atrial
Matthew M Kalscheur1, Matthew R Martini1, Marcus Mahnke2
1Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
Insights
A new heparin dosing system improved anticoagulation during atrial fibrillation (AF) ablation, reducing complications. This clinical decision support system (CDSS) ensures safer AF ablation procedures.
Area of Science:
- Cardiology
- Medical Informatics
- Interventional Cardiology
Background:
- Cerebral thromboembolism is a rare complication of atrial fibrillation (AF) ablation, often linked to inadequate intraprocedural anticoagulation.
- Maintaining therapeutic anticoagulation is crucial to prevent silent cerebral ischemia during AF ablation.
Purpose of the Study:
- To evaluate a computerized clinical decision support system (CDSS) for intraprocedural anticoagulation dosing during AF ablation.
- To determine if the CDSS improves anticoagulation outcomes and reduces complication risks.
Main Methods:
- The Digital Intern dosing algorithm, an adaptive, rule-based CDSS, was implemented for heparin dosing.
- Initial doses were based on patient weight, baseline ACT, and outpatient anticoagulants, with subsequent adjustments based on real-time ACT.
- Outcomes from 139 cases using the algorithm were compared to 50 pre-algorithm cases.
Main Results:
- Procedures using the CDSS reached the target activated clotting time (ACT) of over 300 seconds significantly faster (17.6 vs. 33.3 minutes).
- The CDSS reduced instances of ACT falling below goal in the left atrium and rising above 400 seconds.
- System Usability Scale scores indicated excellent usability (96 ± 5).
Conclusions:
- A heparin dosing CDSS, utilizing rules and adaptive patient response, effectively improved therapeutic ACT maintenance during AF ablation.
- The system demonstrated high usability among nursing staff, suggesting practical clinical value.
Background:
Cerebral thromboembolism during atrial fibrillation (AF) ablation is an infrequent (0.17%) complication in part owing to strict adherence to intraprocedural anticoagulation. Failure to maintain therapeutic anticoagulation can lead to an increase in events, including silent cerebral ischemia.
Objective:
To evaluate a computerized, clinical decision support system (CDSS) to dose intraprocedural anticoagulation and determine if it leads to improved intraprocedural anticoagulation outcomes during AF ablation.
Methods:
The Digital Intern dosing algorithm is an adaptive, rule-based CDSS for heparin dosing. The initial dose is calculated from the patient's weight, baseline activated clotting time (ACT), and outpatient anticoagulant. Subsequent recommendations adapt based on individual patient ACT changes. Outcomes from 50 cases prior to algorithm introduction were compared to 139 cases using the algorithm.
Results:
Procedures using the dosing algorithm reached goal ACT (over 300 seconds) faster (17.6 ± 11.1 minutes vs 33.3 ± 23.6 minutes pre-algorithm, P < .001). ACTs fell below goal while in the LA (odds ratio 0.20 [0.10-0.39], P < .001) and rose above 400 seconds less frequently (odds ratio 0.21 [0.07-0.59], P = .003). System Usability Scale scores were excellent (96 ± 5, n = 7, score >80.3 excellent). Preprocedure anticoagulant, weight, baseline ACT, age, sex, and renal function were potential predictors of heparin dose to achieve ACT >300 seconds and final infusion rate.
Conclusion:
A heparin dosing CDSS based on rules and adaptation to individual patient response improved maintenance of therapeutic ACT during AF ablation and was rated highly by nurses for usability.
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