Key Points
- Determine the duration of effective heparin anticoagulation during cardiac catheterization and validate a protocol for protamine reversal.
- Evaluated the duration of heparin anticoagulation via activated partial thromboplastin time (APTT) in 201 patients undergoing cardiac catheterization and angiography.
- Defined adequate anticoagulation as APTT prolongation greater than or equal to two times the upper limit of normal.
- Formulated a protamine dosing schedule based on initial findings in 78 patients and tested it prospectively in 101 consecutive patients.
- Adequate anticoagulation was maintained in 100% of patients when procedures ended within 40 minutes, but inadequate anticoagulation rose to 9%–25% between 40 and 89 minutes and reached 58% after 90 minutes.
- Protamine administration restored clotting times to the normal range in 92% of patients, reducing mean APTT from 84.1 ± 19.4 seconds to 27.4 ± 2.5 seconds (p < 0.001).
- In patients who did not fully normalize after protamine, APTT remained only 2.8 ± 1.4 seconds (range 0.7–5.5 seconds) above normal.
Structured PICO
Does a specific protamine dosing protocol effectively reverse heparin anticoagulation during cardiac catheterization?
PPopulation201 patients undergoing cardiac catheterization and angiography
IInterventionHeparin administration for anticoagulation and subsequent reversal with a protamine dose estimation protocol
OOutcomeDuration of effective anticoagulation (APTT prolongation ≥ 2 times the upper limit of normal) and return of clotting studies to normal range after protaminesurrogate
Heparin provides adequate anticoagulation for cardiac catheterization procedures under 40 minutes, and a simple protamine protocol can reliably reverse its effects.