Thromboembolic Complications
From beginning to end, neurointerventional procedures of any kind
predispose patients to having thromboembolic complications. Albeit
somewhat ironic, as the discussion relates to stroke intervention and
removal of thrombus causing LVO, the risk of thromboembolic
complications remains. There is an inherent risk of embolic material
forming on catheters and guidewires introduced into the vasculature.
This risk can be reduced by cleanliness, organized back table management
of catheters and wires as they are introduced and removed from the body.
In addition, arterial dissection and vasospasm caused by the guide
catheter prior to microcatheter and microwire manipulation can be
associated with thromboemboli. Heparinization of the patient is a
strategy used by many to minimize the thromboemboli alongside
intrarterial verapamil in select instances of severe vasospasm induced
by catheters.
More concerning for the neurointerventionist is the possibility of
preexisting clot fragments dislodging and leading to embolization of new
territory (ENT) due to manipulation of an endovascular device. Distal
embolization is a legitimate concern which can be handled with different
approaches. The use of stent retrievers of any kind mandates that a
lesion be crossed with a microwire for facilitating the unsheathing of
the stent retriever device. The mere act of crossing a lesion is in
itself an opportunity to dislodge clot debris downstream. Companies in the neurovascular sector tout varying components of their stent retriever devices
including stent length, cell size, radial force, and factors which may
allow for better clot engagement. A plethora of devices ranging from stent retrievers to balloon guide catheters (BGC) fill the toolbox of the neurointerventionist and should be used based on his/her comfort and experience level with the understanding that no device is immune from complications. Table 1 demonstrates several of these tools, some of which are FDA approved for use in MT.
The role of direct aspiration versus stent-retrievers is an ongoing debate in stroke and also the subject of ongoing trials. The ASTER trial showed no statistically significant differences in procedural complications like sICH and embolisation in a new territory between stent-retriever and ADAPT (a direct aspiration first-pass technique). Overall, each device has its unique
benefits, however there is no clear discrepancy with regard to ENT.
Newer generation devices attempt to account for clot fragmentation in
their design. For example, EmboTrap (Neuravi, Ireland) features an inner stent
channel within an outer stent (Fig 1).
Embolization of New Territories