Background: Animal studies suggest that ischemic preconditioning prolongs coagulation times.
Objective: Because coagulation changes could hinder the translation of preconditioning into clinical settings where hemorrhage may be an issue, such as ischemic or hemorrhagic stroke, we evaluated the effects of remote ischemic preconditioning (RIPC) on coagulation in patients undergoing RIPC after aneurysmal subarachnoid hemorrhage (SAH).
Methods: 21 patients with SAH (mean age 56.3) underwent 137 RIPC sessions, 2-12 days following SAH, each consisting of 3-4 cycles of 5-10 minutes of lower limb ischemia followed by reperfusion. Partial thromboplastin time (PTT), prothrombin time (PT), and international normalized ratio (INR) were analyzed before and after sessions. Patients were followed for hemorrhagic complications.
Results: No immediate effect was identified on PTT (mean pre-RIPC 27.62 sec, post-RIPC 27.54, p=0.82), PT (pre-RIPC 10.77 sec, post-RIPC 10.81, p=0.59) or INR (pre-RIPC 1.030, post-RIPC 1.034, p=0.57) after each session. However, a statistically significant increase of PT and INR was identified after exposure to at least 4 sessions (mean PT pre-RIPC 11.33 sec, post-RIPC 12.1, p=0.01; INR pre-RIPC 1.02, post-RIPC 1.09, p=0.014, PTT pre-RIPC 27.4, post-RIPC 27.85, p=0.092) with a direct correlation between the number of sessions and the degree of increase in PT (Pearson=0.59, p=0.007) and INR (Pearson=0.57, p=0.010). Prolonged coagulation times were not observed in controls. No hemorrhagic complications were associated with the procedure.
Conclusion: RIPC by limb ischemia appears to prolong the PT and INR in human subjects with SAH after at least 4 sessions, correlating with the number of sessions. However, values remained within normal range and there were no hemorrhagic complications.
From: Effects of Remote Ischemic Preconditioning on the Coagulation Profile of Patients with Aneurysmal Subarachnoid Hemorrhage: A Case-Control Study by Mayor et al.