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FIGURE 4.2 Seventy-three-year-old female with sudden right hemiparesis, left facial weakness, dysarthria, nausea, and downbeat nystagmus. Posterior circulation angioplasty demonstrated occlusion of the proximal basilar artery (arrows— a and b). Note the retrograde opacification of the superior cerebellar arteries through postero-inferior cerebellar to superior cerebellar arteries collaterals (b).

FIGURE 4.2 Seventy-three-year-old female with sudden right hemiparesis, left facial weakness, dysarthria, nausea, and downbeat nystagmus. Posterior circulation angioplasty demonstrated occlusion of the proximal basilar artery (arrows— a and b). Note the retrograde opacification of the superior cerebellar arteries through postero-inferior cerebellar to superior cerebellar arteries collaterals (b).

FIGURE 4.2 (Continued) A compliant balloon was used to perform angioplasty (c). Postangioplasty angiogram demonstrated complete recanalization of the basilar artery and its major branches (d and e). MRI performed 2 days later demonstrated only small areas of infarction in the cerebellar hemispheres (arrows—f and g) but no brainstem or occipital infarcts.

lead to rethrombosis.17 Given the risks of procedural complications, such as vessel rupture and distal embolization, we tend to reserve this technique as salvage therapy for patients whose flow cannot be restored by more conservative methods. However, this technique has probably become safer with the use of low-pressure, more compliant bal-loons.68,75

Two devices that use different laser technologies have been used to disrupt intra-cranial clots. The Endovascular Photoacoustic Recanalization (EPAR; Endovasix Inc., Belmont, CA) is a mechanical clot fragmentation device based on laser technology. However, the emulsification of the thrombus is due to mechanical thrombo-lysis and not a direct laser-induced ablation. The photonic energy is converted to acoustic energy at the fiberoptic tip through creation of microcavitation bubbles. In a recent study, in which 34 patients (10 ICA, 12 MCA, 1 PCA, and 11 vertebrobasilar occlusions) with a median NIHSS of 19 were treated with EPAR, the overall intention-to-treat recanalization rate was 41.1% (14/34). Vessel recanalization occurred in 11 of 18 patients (61.1%) in whom complete EPAR treatment was possible. Additional treatment with IA rt-PA occurred in 13 patients. One patient had a vessel rupture resulting in fatality. Symptomatic intracerebral hemorrhages occurred in two patients (5.9%). The overall mortality rate was 38.2%.76

The LaTIS laser device (LaTIS, Minneapolis, MN) uses the slow injection of contrast material as a ''light pipe'' to carry the energy from the catheter to the embolus.77 The device was evaluated in a safety and feasibility trial at two U.S. centers. A preliminary account reported that the device could not be deployed to the level of the occlusion in 2 of the first 5 patients, and enrollment stopped at 12 patients. Although the catheter design was changed, an efficacy trial has not been pursued.78

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