Blood Flow Changes Caused by Distal Filter Protection and Catheter Aspiration in the Internal Carotid Artery during Carotid Stenting: Evaluation Using Carotid Doppler Sonography

Abstract

BACKGROUND AND PURPOSE:If blood flow in the ICA is reduced by the use of a distal filter during CAS, flow stagnation proximal to the filter occurs and this increases the probability of floating debris. The floating debris that remains after filter retrieval may cause cerebral embolism. However, if blood flow is increased by aspiration of blood from the ICA through an aspiration catheter, debris could be removed while the filter is still in place. The purpose of this study was to investigate blood flow changes in the ICA induced by filter use and aspiration.

Propagation-based phase-contrast X-ray microtomography of a cerebral protection device retrieved after carotid artery stenting

“…Therefore, the absence of focal neurologic deficits in our patients is attributable to the CPD preventing embolic events by filtering small numbers of significantly large particles of embolic debris. Moreover, no instance of filter-related flow arrest occurred, probably because the percentage of obstructed pores was much lower than the reported values that cause slow-flow (50%) and noflow (88.5%) phenomena (Casserly et al, 2005;Roffi et al, 2008;Sorimachi et al, 2010Sorimachi et al, , 2011. Interestingly, we found debris larger than the size of pores even on the outer surface of the CPD.…”

“…. The blood flow velocity may be decreased after the deployment of a CPD and increased after its retrieval, even in patients with normal angiographic flow (Casserly et al, 2005;Roffi et al, 2008;Sorimachi et al, 2011). The flow impairment might be due to obstruction of the CPD pores, so reducing the total amount of embolic debris, such as by the aspiration of blood samples, may be a useful management intervention (Sorimachi et al, 2010).…”

“…The rupturing or squeezing of atheroemboli during CAS can potentially trigger platelet aggregation and the vasoactive substances contained within a plaque or thrombus could cause vasospasm. This could in turn result in pores containing a mixture of plaque particles, fibrin and platelet aggregation reducing the blood flow through a CPD even in the presence of only small particles (Casserly et al, 2005;Piñ ero et al, 2009;Sorimachi et al, 2011).…”

Pathology of embolic debris in carotid artery stenting

“…After closure of the filter basket, an increase in blood flow causes a proportional increase in wall shear stress in the internal carotid artery, which probably releases fragments from vulnerable plaque and debris particles trapped between the stent struts and the arterial wall . This is one of the suspected mechanisms causing cerebral embolism after filter retrieval . Microembolization during CAS not only occurs during the filter protection [wall apposition and membrane pore size], but also a good number occurs before the filter is up , and some occurs after the procedure, with open and closed cell designs.…”

Inadvertent Carotid Artery Occlusion Due to a Stent-Related Accordion Effect: Clinical Experience with a Retrievable Stent to Unfold the Vascular Wall and Restore Flow

“…Inadvertent occlusion of a carotid artery during stenting is a rare but catastrophic complication that can result in procedure-related stroke and requires an immediate rescue maneuver. The mechanisms underlying acute arterial occlusion can include embolic protection device (EPD)-related flow arrest, 1 arterial dissection, 2 vasospasm, 3,4 and the accordion effect. 5 The differential diagnosis can be challenging, but is crucial for appropriate management.…”