IVT and its success

Q: A 72-year-old male, with past medical history of only hypertension (HTN) found to have a  witnessed stroke in a restaurant. He is promptly brought to the hospital within 60 minutes of the stroke. Intravenous thrombolysis (IVT) was given. Thrombus in which of the following vessels may be more resistant to 'bust'? (select one) 

A) internal carotid artery 

B) middle cerebral artery 

Answer: A

The success of IVT depends not only on early treatment but also on clot size and site. More proximal clots are more resistant to thrombolysis. 

This is for the two major reasons. First, a clot in the internal carotid artery will probably be larger (the larger the diameter, the larger the clot). Second, the chances of developing extended clots in the adjacent arteries are higher (a long thrombus). 

Another major factor that affects the success of IVT is the burden of atherosclerotic lesions in the vessel, which may prevent the full recanalization of the vessel. Moreover, thrombus permeability, i.e., residual flow, also counts. The higher the thrombus permeability, the higher the chances of successful IVT

#neurology 

References: 

 1. Menon BK, Al-Ajlan FS, Najm M, et al. Association of Clinical, Imaging, and Thrombus Characteristics With Recanalization of Visible Intracranial Occlusion in Patients With Acute Ischemic Stroke. JAMA 2018; 320:1017. 

 2. Linfante I, Llinas RH, Selim M, et al. Clinical and vascular outcome in internal carotid artery versus middle cerebral artery occlusions after intravenous tissue plasminogen activator. Stroke 2002; 33:2066. 

 3. Saqqur M, Uchino K, Demchuk AM, et al. Site of arterial occlusion identified by transcranial Doppler predicts the response to intravenous thrombolysis for stroke. Stroke 2007; 38:948. 

 4. Yoo J, Baek JH, Park H, et al. Thrombus Volume as a Predictor of Nonrecanalization After Intravenous Thrombolysis in Acute Stroke. Stroke 2018; 49:2108. 

 5. Seners P, Turc G, Maïer B, et al. Incidence and Predictors of Early Recanalization After Intravenous Thrombolysis: A Systematic Review and Meta-Analysis. Stroke 2016; 47:2409.