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Variability of Activated Clotting Time by Site of Sample Draw During Percutaneous Coronary Intervention: A
Jacqueline H Morris1, Junsoo Alex Lee1, Scott McNitt1
1Division of Cardiology, 6923University of Rochester School of Medicine, Rochester, NY, USA.
Insights
Activated clotting time (ACT) measurements during percutaneous coronary intervention (PCI) are higher when drawn from the guide catheter compared to the access sheath. This difference impacts anticoagulation management and research reporting.
Area of Science:
- Cardiology
- Hematology
- Medical Devices
Background:
- Activated clotting time (ACT) is crucial for monitoring unfractionated heparin during percutaneous coronary intervention (PCI).
- Institutional observations indicated variability in ACT values based on arterial sampling sites.
Purpose of the Study:
- To prospectively evaluate differences in ACT values obtained simultaneously from the coronary guide catheter and the arterial access sheath during PCI.
- To identify clinical factors associated with discrepancies in ACT measurements.
Main Methods:
- Prospective enrollment of patients undergoing PCI with unfractionated heparin.
- Simultaneous arterial blood sampling from the guide catheter and access sheath.
- Analysis of Hemochron ACT values and correlation with clinical variables.
Main Results:
- Mean guide catheter ACT (327 ± 62 s) was significantly higher than sheath ACT (257 ± 44 s), with a mean difference of 70 ± 60 s (P < .001).
- Approximately 90% of guide catheter ACTs exceeded sheath ACTs.
- Lower weight-adjusted heparin doses and absence of diabetes were linked to larger ACT value differences.
Conclusions:
- ACT values are substantially higher when measured via the guide catheter compared to the access sheath during PCI.
- This observed difference necessitates consideration in anticoagulation management and research reporting.
- Further investigation into the biological mechanisms underlying this discrepancy is warranted.
Abstract:
The activated clotting time (ACT) assay is used to monitor and titrate anticoagulation therapy with unfractionated heparin during percutaneous coronary intervention (PCI). Observations at our institution suggested a considerable difference between ACT values drawn from varying arterial sites, prompting the current study. Patients undergoing PCI with unfractionated heparin therapy were prospectively enrolled. Simultaneous arterial blood samples were drawn from the access sheath and the coronary guide catheter. Differences between Hemochron ACT values were determined, and potential interactions with clinical variables were analyzed. Immediately postprocedure, the simultaneous mean guide and sheath ACTs were 327 ± 62 seconds and 257 ± 44 seconds, respectively, with a mean difference of 70 ± 60 seconds (P < .001). Nearly all (90%) ACT values obtained via the guide catheter were higher than the concurrent ACT drawn from the sheath. Logistic regression analysis demonstrated that lower weight-adjusted heparin doses and absence of diabetes were associated with a greater difference between the ACT values. We conclude that the ACT value is substantially greater when assessed via the guide catheter versus the access sheath. Although the biological mechanisms require further study, this difference should be considered when managing anticoagulation during PCI and when reporting ACT as part of research protocols.
