arterial dissection is the second leading cause of stroke in patients younger than age 45 ( lisovoski and rousseaux , 1991 ) .
current endovascular recanalization approaches for acute stroke focus on either removal of the distal clot using either a retrieval device or aspiration , or displacement via angioplasty and/or self - expanding stent .
this approach is problematic in the setting of cervical carotid or vertebral dissection because microcatheter and microguidewire navigation across the dissection has the potential to enlarge the false lumen .
we present a case of an acute carotid terminus occlusion caused by clot from a cervical carotid dissection initially worsened by attempts at gaining microcatheter access to the distal clot .
however , with proximal flow arrest and primary aggressive proximal guide catheter aspiration , we were able to successfully recanalize the internal carotid artery and its branches , leading to a better than expected clinical outcome .
a 34-year - old man was driving a car when he was hit by another car causing the vehicle to spin completely around .
he walked away from the accident with neck discomfort but no neurologic deficits . a week later , he developed sudden onset complete left arm weakness and global aphasia .
intravenous thrombolytics were given , and he was transferred to our hospital with a national institute of health stroke scale score of 16 .
initial cervical carotid catheter angiography revealed a right posterior cervical carotid intimal flap indicating an intimal - media arterial dissection ( figure 1 ) .
cerebral views showed delayed anterograde filling in the internal carotid artery associated with a carotid terminus occlusion ( figure 2 ) .
attempts at advancing a penumbra 41 reperfusion catheter ( penumbra inc , alameda , ca , usa ) intracranially were unsuccessful because the edge of the reperfusion catheter could not be advanced past the dissection flap at the distal cervical carotid artery ( figure 3 ) .
subsequent angiography showed a more proximal occlusive lesion , suggesting that the intimal flap had extended into the petrous carotid with further compromise of the luminal diameter ( figure 4 ) .
right lateral common carotid digital subtraction angiography cervical view showing an intimal flap and smooth tapered cervical carotid dissection extending up to the cervical / petrous junction .
right lateral common carotid digital subtraction angiography cerebral view showing markedly delayed anterograde flow in the internal carotid artery with a supraclinoid occlusion and flow defects in petrous and cavernous section of carotid artery .
right lateral common carotid digital subtraction angiography cervical view showing microguidewire in the dissected segment of cervical carotid artery , worsening the underlying pathology .
right lateral common carotid digital subtraction angiography cerebral view showing a near occlusive intimal flap at the cervical petrous section . using a merci 8f balloon guide catheter ( concentric medical , mountain view , ca
, usa ) , a merci 18l ( concentric medical , mountain view , ca , usa ) microcatheter was advanced over a microguidewire into the m1 segment . using standard technique , with a pull lasting 23  min , an l6 merci retrieval device ( concentric medical , mountain view , ca , usa ) retrieved some clot but only timi
the microcatheter was again advanced up into the m1 segment , a l5 merci retriever ( concentric medical , mountain view , ca , usa ) deployed , the balloon inflated , and this time , more aggressive proximal aspiration was performed using a 60-cc syringe .
the retriever was visualized under fluoroscopy not to deform its shape during the entire withdrawal , which again lasted only about 1  min , suggesting little or no clot was engaged or retrieved .
subsequent angiographic runs , however , demonstrated timi 3 recanalization of the internal carotid artery with a persisting but non - occlusive intimal flap along the petrous / cervical section ( figure 5 ) .
after proximal flow arrest and aggressive proximal guiding catheter aspiration , timi 3 flow in the internal carotid is restored . the dissection is now seen to extend into the petrous section , but is not flow limiting . once flow was restored , we decided against placing a stent into the cervical and petrous sections of the carotid artery .
the patient had already received 0.9  mg / kg of intravenous t - pa hours before .
we felt that he would have an unacceptably high risk of hemorrhagic transformation by adding the loading dose of abciximab as a prerequisite for stent placement .
mri and mra of the head and neck was done the following day , showing a stable appearance to the dissection and a right superior division mca territory stroke ( figure 6 ) .
he was discharged from the hospital 5  days later with an nihss of 1 .
six weeks later , his nihss score remained 1 with slight word finding difficulties and mra showed persistence of the right cervical / petrous dissection .
he was maintained on anticoagulation for 6  months and on 12  month followup , his nihss score was 0 and he was back to work in construction .
diffusion weighted mri showing increased signal in a superior division middle cerebral artery branch territory .
in patients younger than age 45 , arterial dissection is a leading cause of stroke ( lisovoski and rousseaux , 1991 ; schievink et al . , 1994 ) .
carotid artery intimal tears leading to dissection usually occur a few centimeters distal to the carotid bulb , at the c2c3 level , and the dissection usually extends distally until the carotid artery enters the foramen lacerum .
the typical angiographic finding is a relatively smooth or slightly irregular tapered mid - cervical narrowing ( provenzale , 1995 ) .
carotid subintimal dissections are dynamic lesions , and depending on the size , can cause just minor luminal narrowing , or complete occlusion . as a result , symptoms are variable and can range from cranial nerve compromise , to a horner 's syndrome , to ischemia in vascular territories distal to the lesion .
most ischemic symptoms occur within 1  week of the onset of pain , as was the time course in this patient ( biousse et al . , 1995 ) .
most infarctions are territorial , rather than borderzone , indicating an embolic rather than hemodynamic etiology ( provenzale , 1995 ) . increasing familiarity with endovascular revascularization devices allows us to tailor our approach based on our attempts at understanding stroke pathophysiology .
mechanical revascularization of severe carotid dissections using microcatheters and wires may worsen the underlying pathology .
dissections are delicate , dynamic lesions that are not easily navigated around using existing biplane angiographic imaging . with an occlusive distal clot ,
furthermore , in the acute phase , anterograde blood flow is steadily applying a force underneath the intimal flap , predisposing it to worsen . with conscious sedation rather than general anesthesia being a commonly used , patient movement during the procedure
is not only to be expected , but adds additional challenge to not only discerning the false from the true lumen , but also navigating a microcatheter past the lesion ( abou - chebl et al . , 2010 ) .
pharmacologic , intra - arterial thrombolysis may also be problematic in the setting of acute stroke caused by arterial dissection .
published small case series of intra - arterial thrombolysis for acute stroke due to arterial dissection have not shown significant rates of rupture of dissected vessels , cervical or subarachnoid hemorrhage , intracranial hemorrhage , or peri - interventional arterial embolism ( arnold et al . , 2000 ) .
however , chemical thrombolytics such as urokinase or t - pa carry the theoretical risk of extending the arterial wall hematoma , independent of the microcatheter inadvertently widening the false lumen .
another approach to this complicated scenario is to treat and stabilize the cervical carotid or vertebral dissection first , thereby facilitating access to the distal intracranial thromboembolus .
several reports have described cervical carotid angioplasty and stent placement as treatment option for arterial dissection ( abboud et al .
this approach may have a role in not only acute recanalization , but also for secondary stroke prevention , permitting immediate and durable recanalization of the artery but associated with use of dual antiplatelet therapy instead of anticoagulation .
first , the passage of a wire or embolic protection device and stent delivery catheter past the dissection may , again , widen the false lumen .
secondly , distal embolic protection devices may not be as easily used as the dissected segment often extends to the cervical / petrous section .
another concern for stent placement in a dissected artery is the weakened structural integrity of the vessel wall , unlike that of an atherosclerotic vessel wall , which is the pathology for which this device is designed to treat
. the vessel may be undergo additional injury with either balloon angioplasty and/or stent placement .
lastly , dissected segments , unlike atherosclerotic lesions for which currently available stents are designed for , are often much longer , and difficult to accurately determine the proximal and distal margins . accurately reopposing
proximal aspiration through an 8f guiding catheter has been previously described in case reports to treat carotid bulb occlusion ( xu et al . , 2005 ) .
however , without a proximal balloon and the ability to induce flow arrest , they were limited in their ability to mechanically disrupt the clot for fear of distal emboli . in both cases however , pretreatment angiography suggested a significant clot burden that was amenable to aggressive proximal aspiration .
the concept behind proximal flow control to support retrieval of thrombus was published prior to the release of the merci retrieval system in 2004 .
it was based on the concept that anterograde flow maintained the clot in place like a cork , and reducing this force would then facilitate its removal ( mayer et al . , 2002 ) .
in our case , precious time was spent gaining access and attempting to retrieve the distal clot with microcatheters and wires .
furthermore , at one point , the dissection was worsened as a result of these maneuvers .
we were most successful with recanalization when we applied proximal flow arrest followed by aggressive proximal aspiration through the 8f guide catheter situated below the dissection .
fortunately , placing the end of the guide catheter at the level of the carotid bulb appears safe as most carotid dissections occur just distal to the bulb .
proximal flow arrest with proximal aspiration appears to be a safe and effective adjunctive technique for these lesions .
some may argue that aspiration alone may have accounted for the recanalization . as such , the dissection is not mechanically disturbed by attempts at advancing a microcatheter past it .
furthermore , flow reversal is associated with a retrograde force on the intimal flap that may facilitate re - apposition of the normal arterial layers .
an analogous situation occurs with an occlusive lesion that extends from the distal cervical carotid to the supraclinoid carotid with intact interhemispheric flow via the anterior communicating artery . again
, passing any type of device through or within the distal aspect of the clot runs the risk of compromising the functioning circle of willis collaterals .
a proximal - to - the - clot approach may have an advantage of preserving the circle of willis collaterals .
the use of acute endovascular stroke therapy for a large artery ischemic stroke secondary to arterial dissections involves unique modifications to the conventional procedural protocol .
this case review highlights the importance of careful navigation of any microcatheters , wires , and devices across the arterial dissection , as well as the potential utility of aggressive aspiration via a large bore guiding catheter proximal to the dissection .
ethics approval statement : this study was approved by rush university medical center , chicago , il , usa , irb#07110702 .
the author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .
 in the setting of an acute stroke caused by arterial dissection , navigating a microcatheter and microguidewire past the dissected artery to gain access to the distal thromboembolic lesion may exacerbate the underlying pathology . 
 we review a case report whereby successful recanalization of an acute carotid terminus occlusion due to intimal - media dissection in the cervical carotid artery emphasizing the importance of aggressive proximal guide catheter aspiration in conjunction with flow arrest from the carotid bulb proximal to the dissection . 
 we discuss the strengths and limitations of this approach and underscore the importance of a pathology - based approach to acute stroke therapy . 
Introduction
Case Report
Discussion
Conclusion
Conflict of Interest Statement