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.