Letter to the Editor: Ultrasound-Assisted Tissue Plasminogen Activator Delivery to Ischemic Strokes
The World Health Organization deﬁnes stroke as ‘rapidly developing clinical signs of focal (or global) disturbance of cerebral function, with symptoms lasting 24 h or longer or leading to death, with no apparent cause other than that of vascular origin’(Armstead et al. 2010). Strokes can be broadly classified into two categories: ischemic and hemorrhagic. The former category comprises 80% of all strokes (Armstead et al. 2010; Murray et al. 2010). In adults, ischemic strokes are the third major cause of morbidity and mortality, surpassed only by heart disease and cancer (Armstead et al. 2010; Murray et al. 2010; Frendl et al. 2011). With increasing longevity and a growing proportion of the population over 65yr in North America, death and disability from strokes can be expected to increase (Murray et al. 2010). Current therapies for ischemic strokes, while effective, have significant hemorrhagic risks to the patient and must be administered within a very narrow timeframe (Frendl et al. 2011; Alexandrov 2010). Therefore, there is a need to investigate novel therapeutic agents as well as improve drug administration techniques to acutely decrease the injury caused to the brain in the event of a stroke, while minimizing the potential for hemorrhages and reperfusion injuries.