Isolated Prolonged Activated Partial Thromboplastin Time and Contact Factor Deficiencies: Case Series and Management Review.
A 67-year-old morbidly obese white female, status post recent aortobifemoral bypass, was transferred to our medical center for an emergent right axillary to bifemoral bypass following a newly diagnosed thrombosis of her graft. The patient had no previous records in our health system and limited preoperative laboratory workup revealed an isolated prolonged
activated partial thromboplastin time of >200 seconds, which was attributed to the UFH administration during her outside hospitalization.
The patient was brought emergently to the operating room where her baseline activated clotting time was 567 seconds; suggesting adequate anticoagulation. During surgery, the ACT was repeated
twice at 1 and 2 hours and results were consistent with adequate anticoagulation without the use of UFH.
Thirty-seven minutes later, following the 2-hour ACT, a thrombus was detected and the surgeon requested an immediate bolus dose of 10,000 units of UFH. ACT was then repeated and found to be >1500 seconds, exceeding the assay detectable limit.
Instrument malfunctioning was suspected; however, a repeated ACT test on a different analyzer revealed similar results. Both analyzers were evaluated intra-operatively by a point of care quality assurance supervisor and were found to be performing within the standard limits. Intra-operative hemostasis was further managed by empirically dosing the patient with 1000 unit/hour of UFH.
Surgery was concluded 5 hours later without further complications and with a final postoperative ACT of 586 seconds. The patient’s post-operative course was unremarkable with no incidence of excessive bleeding or thrombotic events.
Res Pract Anesthesiol Open J. 2016; 1(1): 19-23. doi: 10.17140/RPAOJ-1-105