Intracranial angioplasty

In a prospective, open-label study, Hill et al. assessed the feasibility of a bridging approach using full-dose IV rt-PA. Following IV infusion of 0.9 mg/kg rt-PA, six patients underwent lAT with rt-PA (maximum dose 20 mg) and one underwent intracranial angioplasty. TIMI 2 or 3 recanalization was achieved in three of these patients. There were no symptomatic ICHs. 

The use of intracranial angioplasty and stenting is strongly supported in the few institutions where the technology exists. Whether these procedures should be attempted in patients outside clinical trials remains controversial. 

Various nondetachable balloons are available for temporary vessel occlusion, angioplasty for vasospasm therapy or remodelling techniques for broad based aneurysms. Larger vessels like the carotid or vertebral artery can be occluded with a double lumen balloon catheter, i.e. Meditech (Cook). For intracranial angioplasty and remodeling smaller, more flexible balloons, like the Hyperglide (MTI), Eclipse (Balt), or the Copernic (Balt) are required. Additionally to these balloons tbe Hyperform microballoon (MTI) can be used for remodelling technique. 

Intracranial angioplasty and stenting may be associated with a high rate of restenosis thus, consistent (ideally non-invasive) follow-up is mandatory. To avoid frequent invasive intra-arterial angiography, FD-CT with intravenously administered contrast agent may emerge as an alternative. 

Indications may be 3D imaging of contrast-enhancing intracranial tumors such as mengingiomas, non-invasive follow-up, e.g., for patients who obtained stent-assisted intracranial angioplasty, or for cerebrovascular imaging when arterial access is problematic. Our pre-hminary data are promising, and further research is required. 

Ueda T, Sakaki S, Nochide I, Kumon Y, Kohno K, Ohta S. Angioplasty after intra-arterial thrombolysis for acute occlusion of intracranial arteries. Stroke 1998 29 2568-2574. 

Lylyk R Cohen JE, Ceratto R, Eerrario A, Miranda C. Angioplasty and stent placement in intracranial atherosclerotic stenoses and dissections. AJNR Am J Neuroradiol 2002 23 430 36. 

Initial tests in the rat revealed a high degree of tissue compatibility of Dat-Tyr-Hex derived polymers. More detailed tests are now in progress. In addition, tyrosine derived polymers are currently being evaluated in the formulation of an intracranial controlled release device for the release of dopamine, in the design of an intraarterial stent (to prevent the restenosis of coronary arteries after balloon angioplasty), and in the development of orthopedic implants. The use of tyrosine derived polymers in these applications will provide additional data on the biocompatibility of these polymers. 

Contraindications Active internal bleeding, arteriovenous malformation or aneurysm, cerebrovascular accident (CVA) with residual neurologic defect, history of CVA (within the past 2 yr) or oral anticoagulant use within the past 7 days unless PT is less than 1.2 X control, history of vasculitis, hypersensitivity to murine proteins, intracranial neoplasm, prior IV dextran use before or during percutaneous transluminal coronary angioplasty (PTCA), recent surgery or trauma (within the past 6 wk), recent (within the past 6 wk or less) GI or GU bleeding, thrombocytopenia (less than 100,000 cells/pl), and severe uncontrolled hypertension... 

Bypass or endarterectomy of proximal vertebral artery stenosis Release of the vertebral artery from compressive fibrous bands or osteophytes Extracranial-to-intracranial procedures to bypass vertebral artery stenosis or occlusion Angioplasty and stenting of the vertebral and basilar arteries... 

Because of the significant correlation with age and a previous history of stroke, it is now widely considered that in patients over 75 years with a history of stroke other therapies, such as primary coronary angioplasty, must be considered. As reported in the GUSTO-1 trial, patients with very high systolic blood pressures have an increased risk of death or disabling stroke (26), and the pulse pressure has been reported to be the clearest predictor of the blood pressure as regards the risk of intracranial hemorrhage (27). 

The treatment of patients with symptomatic intracranial atherosclerotic disease can be summarized into prevention of occurrence of intraluminal thrombosis, plaque stabilization, and control of risk factors for atherosclerosis. Anticoagulation (compared with aspirin) has not shown to be beneficial in patients with intracranial atherosclerotic disease [24]. Current guidelines recommend that aspirin alone, the combination of aspirin and extended release dipyridamole, and clopidogrel monotherapy (rather than oral anticoagulants) are aU acceptable options [24]. hi patients with hemodynamically sigifificant intracranial stenosis who have symptoms despite medical therapies (antithrombotics, statins, and other treatments for risk factors), the usefulness of endovascular therapy (angioplasty and/or stent placement) is uncertain and is considered investigational [22, 25],... 

The Alligator Retrieval Device (ARD, ev3 Neurovascular, Irvine, C A) is a retriever with four small grasping jaws attached to the tip of a flexible wire designed to be used in conjunction with 0.21 in. miaocatheter [37]. This device has been used to treat six patients with intracranial clots (predominantly MCA) resulting in rapid clot removal and clinical improvement in all cases. Two of the six patients had experienced failure of another clot retrieval device, and three patients required no systemic thrombolytics [38]. The In-Time Retriever (Boston Scientific, Natick, MA) has 4-6 wire loops and tends to bow when opened but has no specific opening to capture the embolus. This device has been successfully used in a case of MCA occlusion resistant to thrombolytics and balloon angioplasty [39] as well as in cases of basilar occlusion [40]. 

Nogueira RG, Schwamm LH, Buonanno FS et al. Low-pressure balloon angioplasty with adjuvant pharmacological therapy in patients with acute ischemic stroke caused by intracranial arterial occlusions. Neuroradiology. 2008 50 331-340... 

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