We had a Hunch!

In this episode Dr. Tess Fitzpatrick, and Dr. Katherine Sawicka Episode Summary In this episode, our guests discuss their recent publication regarding the real-world challenges of using Unfractionated Heparin (UFH) in acute stroke patients. The team explores the data behind the "hunch" that UFH often fails to achieve therapeutic levels quickly or consistently, and discusses the pragmatic shift toward Low Molecular Weight Heparin (LMWH). The Clinical Problem Traditionally, IV Unfractionated Heparin (UFH) is the go-to for acute anticoagulation in stroke (e.g., for free-floating thrombi) because it has a short half-life and is reversible. However, achieving a therapeutic aPTT is difficult, often leading to patients being sub-therapeutic or supra-therapeutic for long periods. Study Design & Indications The team conducted a retrospective study over three years, identifying stroke patients treated with UFH for specific cerebrovascular indications. Three main indications studied: Intraluminal thrombus (free-floating thrombus). Cerebral Venous Sinus Thrombosis (CVST). Cardiogenic indications (e.g., cardiac thrombus, low ejection fraction). The Results: Confirming the Hunch Delayed Efficacy: For the first time the aPTT went over 70 seconds, 35% of the time it took between 12 and 24 hours to occur. Lack of Stability: 66% of patients never reached a "steady state" (defined as two consecutive therapeutic aPTT measurements). Overshoot: Patients spent 25% of the time in the supra-therapeutic range (too high), though major bleeding events were rare in this specific sample. Variability Causes: High variability is partly due to the non-specific binding of UFH to plasma proteins, monocytes, and endothelial cells, which are often elevated in acute phase reactants during stroke. The Shift to Low Molecular Weight Heparin (LMWH) The center is moving away from UFH and toward LMWH for these indications. Benefits of LMWH: It offers a predictable dose-response relationship, greater stability, and higher bioavailability compared to UFH. The "Safety Blanket" Myth: While clinicians like UFH because of the reversal agent Protamine, the team notes that Protamine is rarely actually used in stroke settings (unlike in cardiac surgery). It often provides a "false sense of security." Pragmatic Management Start Low: The team suggests starting LMWH at lower doses (e.g., roughly 2/3 dose) and titrating up, rather than immediately giving a full dose, to mimic the gradual onset of UFH without the instability. Exceptions: UFH may still be preferred for patients with severe renal failure or those requiring imminent surgery (within 4 hours). There is a desperate need for randomized control trials (RCTs) specifically in the stroke population comparing Low Molecular Weight Heparin vs. Unfractionated Heparin to solidify these best practices. 🎙️ Meet the Guests🧠 Key Topics & Study Findings🏥 Clinical Implications & Practice Changes📚 Call to Action