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Activated clotting-time variability in patients undergoing coronary angioplasty
M F Warner1, M S Mian, J C Missri
1Department of Internal Medicine, St. Francis Hospital and Medical Center, Hartford, Connecticut.
Insights
Activated clotting time (ACT) measurements from arterial and venous samples are not comparable during percutaneous transluminal coronary angioplasty (PTCA). Significant variability exists, impacting anticoagulation assessment in patients undergoing this procedure.
Area of Science:
- Cardiology
- Vascular Surgery
- Anesthesiology
Background:
- Activated clotting time (ACT) is crucial for monitoring anticoagulation during percutaneous transluminal coronary angioplasty (PTCA).
- Uncertainty exists regarding the comparability of ACT measurements from arterial versus venous blood samples in this context.
Purpose of the Study:
- To evaluate the agreement between arterial and venous ACT measurements in patients undergoing PTCA.
- To determine if these two sample sources provide interchangeable anticoagulation data.
Main Methods:
- ACT determinations were performed on sequential arterial and femoral venous blood samples.
- Samples were collected from 115 patients immediately after PTCA in the catheterization laboratory.
Main Results:
- Venous ACT values exceeded arterial ACT in 55% of patients.
- Arterial and venous ACT differed by over 100 seconds in 10 patients.
- In 20% of cases, one ACT measurement was ≥300 seconds while the other was <300 seconds.
Conclusions:
- There is substantial variability between arterial and venous ACT measurements in patients undergoing PTCA.
- These findings suggest that arterial and venous ACT values should not be used interchangeably for anticoagulation assessment during PTCA.
Abstract:
Although the activated clotting time (ACT) is commonly used to assess adequacy of anticoagulation during percutaneous transluminal coronary angioplasty (PTCA), there is uncertainty whether measurements on samples from the arterial and venous circulations are directly comparable. We performed ACT determinations on 115 patients undergoing PTCA at our institution. Blood samples were drawn in a sequential fashion from the arterial and femoral venous sheaths at the conclusion of each case, and ACT determination were performed in the catheterization laboratory immediately thereafter. The venous ACT exceeded the arterial value in 63 patients (55%), and was identical in only 2 instances. The arterial and venous ACT differed by more than 100 s in 10 patients. In 23 patients (20%) one ACT determination was > or = 300 s, while the value from the other circulation was < 300 s. We conclude that there is substantial variability between arterial and venous ACT determinations in heparinized patients undergoing PTCA.