Patent foramen ovale (PFO) is an important underlying source of cryptogenic stroke (CS) associated with hematologic procoagulability. However, the association of genetically identified hyperocagulability and paradoxical embolism has been difficult to establish due to retrospective analysis and the limited numbers of of known genetically identified hypercoagulable conditions. In this study, we explored the utility of conventional coagulation status in PFO related stroke, as the patients may harbor genetically unidentified hyperocoagulable conditions.
Method:
Eligible pts were prospectively recruited in accordance with IRB, and underwent conventional coagulation testing (PT/PTT) testing within 12 hours of stroke. All patients underwent full cryptogenic workup such as MRI/MRA, mobile cardiac outpatient telemetry (>30 days), cardiac echo, and hypercoagulable testing.
Results:
We screened 4,831 pts admitted with acute neurologic diseases, and recruited 358 eligible acute ischemic stroke pts. 54 (15.1%) pts had CS and 32 pts had PFO related stroke. While there is no difference between PFO-related CS and PFO-unrelated CS on full hypercaogulable screen (protein S, protein C, FVL, PTGM, ATIII, APLAb, LA, hcy), aPTT was statistically significantly shortened in PFO-related stroke patients (PFO CS vs. non-PFO CS: aPTT 27.2±4.1s vs. 29.9±2.3s). ROC curve indicates early shortened aPTT can predict PFO related stroke (sensitivity 70%, specificity 81.5%, p=0.017) (see Figure).
Conclusion:
We found real time aPTT to be significantly shortened in patients eventually diagnosed with paradoxical embolism related to PFO. While studies in larger pt cohorts accounting for other potential confounders are underway, this proof-of-concept study demonstrates the importance and utility of early conventional coagulation testing in identifying paradoxical embolism. Pts with shortened aPTT may need additional workup for other underlying hypercoagulable conditions.