Finally, arterial reocclusion was related to lesser neurological improvement during hospitalization and lower rates of three-month functional independence in two stroke registries of systemic thrombolysis [14] and [19]. Early reocclusion can be detected in real-time with continuous 1-h TCD-monitoring during iv-tPA infusion [13] and [14]

and our pilot study demonstrated that TCD can detect arterial reocclusion during or within an hour after completion of intra-arterial procedures [18]. There is also small anecdotal ABT-263 chemical structure data indicating that continuous ultrasound surveillance may provide rapid detection of reocclusion (Fig. 1) as well as persistent occlusion and assist in subsequent management decisions including GPIIb-IIIa antagonist administration [21] or direct thrombin inhibitor administration (such as argatroban) [22] in patients with END due to reocclusion. The following therapeutic measures may be considered in patients with END caused by arterial reocclusion: • TCD-monitoring of intracranial vessel patency during the first hours following reperfusion procedures (especially during the first 2 h following tPA-bolus). The Starling resistor model defines cerebral perfusion pressure as the difference between arterial pressure and venous, intracranial, or tissue pressure (whichever is highest)

[23]. Blood flow occurs due to pressure gradient with blood following the path http://www.selleck.co.jp/products/s-gsk1349572.html of least resistance and flow diversion being caused by effective outflow differences for the Starling resistors www.selleckchem.com/products/AG-014699.html [23]. The concept of blood flow steal in the cerebral circulation is well established [24]. In brain, hemodynamic steal and shunts were documented with angiomas and hypervascularized brain tumors [24] and [25]. Neurological symptoms were linked to cerebral blood flow reduction with arterio-venous malformations [24] or rare cases of the

subclavian steal syndrome [26]. The concept of arterial steal has been evaluated in real-time in the setting of ACI. Alexandrov et al. observed paradoxical decreases in flow velocity during episodes of hypercapnia in vessels supplying ischemic areas of the brain at the time of expected velocity increase in nonaffected vessels [27]. Hypercapnia triggered vasodilation more effectively in normal vessels, thus producing arterial blood flow steal toward the path of least resistance (Fig. 2) [27]. The hemodynamic steal was also documented on CT perfusion before and after challenge with acetazolamide (Diamox). The steal magnitude was linked to severity of neurological worsening in patients with acute stroke [27] and [28]. This intrancranial steal phenomenon when coupled with END (determined as an increase of >2 points in NIHSS-score) was termed “Reversed Robin Hood Syndrome (RRHS)” for an analogy with “rob the poor to feed the rich [27]. Sharma et al.