Background: Multiple randomized controlled trials have demonstrated that mechanical thrombectomy with a stent-retriever (stent) is beneficial for patients with acute ischemic stroke (AIS) caused by thrombotic intracranial large vessel occlusion. However, the mechanisms of interaction between stent and thrombus are largely unknown. We aimed to study the interaction between stent and thrombus following thrombectomy for AIS.
Hypothesis: If the interaction between stent and thrombus following thrombectomy for AIS is more than merely a mechanical wrapping around stent struts, then we will observe multiple types of interaction between stent and thrombus.
Methods: Seven stents were collected directly after thrombectomy. The stents, with thrombi still entrapped (Fig. 1), were prepared for scanning electron microscopy (SEM) to analyse stent-thrombus interactions and associated thrombus surfaces at multiple interaction sites1. A total of 94 interaction sites were analyzed by SEM by two independent raters. A Chi-squared test was used to perform statistical analyses. A p-value <0.05 was considered statistically significant.
Results: Stent-thrombus interaction was found to be predominantly active (Fig. 1C, 61±30%) and, to a lesser extent, mechanical (Fig. 1B, 39±30%). A strong correlation was found between interaction type and thrombus surface, with active adhesion predominantly associated with a dense thrombus surface, and mechanical interaction with a loose thrombus surface (p=0.003).
Conclusion: The interaction between stent and thrombus was predominantly active which corresponded with a dense surface. As alteplase, is routinely given in these patients, may interfere with active stent-thrombus interaction, its indication should be carefully considered in patients who are candidates for stent based thrombectomy. The small number of stents studied, do indicate that results should be interpreted with caution.
1Neurology. 2017 Jan 10;88(2):216-217