Discussion
Here, we report a case of embolic
stroke during PCI treated with coronary thrombus aspiration. In this
case, several balloon dilatations and incomplete aspiration thrombectomy
migrated thrombus in the RCA more proximally and the thrombus was
subsequently released into the aorta by the backflow of the contrast
injection (Supplemental file).
Major randomized trials and meta-analyses have concluded that thrombus
aspiration is not associated with a reduction in mortality in myocardial
infarction (1-4). In a trial of routine aspiration thrombectomy with PCI
versus PCI alone in patients with STEMI (TOTAL), manual aspiration
thrombectomy was associated with stroke (hazard ratio, 2.08; p = 0.002)
(2). Therefore, current guidelines do not recommend routine thrombus
aspiration (5,6). A previous study elucidated the mechanism of
aspiration thrombectomy-associated stroke involved an
incompletely-aspirated thrombus dislodging inside the guide catheter and
subsequently being injected through the guide catheter into the systemic
circulation (7). Therefore, it is necessary to open the connector of the
guide catheter and drain the thrombus out of the body in order to
prevent its release into the systemic circulation.
On the other hand, we captured the moment that the floating thrombus in
the RCA is ejected by the backflow of contrast injection, which is an
extremely rare mechanism of aspiration thrombectomy-associated stroke.
Because the thrombus is located in the RCA rather than in the guide
catheter, it is impossible to drain out of the body as described above.
In general, when aspiration thrombectomy is performed, it is important
to engage the guide catheter in the ostium of the coronary artery deeply
and to use a larger catheter so that the coronary thrombus does not pass
through the gap between the guide catheter and the coronary artery.
However, when the guide catheter is large, the contrast volume and
pressure increase, which can cause displacement of coronary thrombus.
Thus, avoiding contrast agent may prevent the aspiration
thrombectomy-associated stroke but detecting the presence of a floating
thrombus require contrast. Thus, the rare complication such as this case
is very difficult to avoid. Intravascular ultrasound, which does not
require contrast injection, can be useful for identifying the volume and
features of the thrombus.