This may be a sign of vessel-wall damage, suggesting a need to evaluate potential clinical sequelae, researchers say.
Several features of mechanical thrombectomy for large vessel occlusion (LVO) stroke, including how distally the devices reached and whether the patient achieved complete recanalization, may be associated with the presence of vascular-wall components in thrombus specimens, according to a Japanese study published online recently in the Journal of NeuroInterventional Surgery.
The authors speculate that the presence of these components is a surrogate marker for vessel-wall injury, which many have important clinical implications.
While the safety and efficacy of stent retriever thrombectomy for the treatment of LVO has been well-established, “device related vessel damage, such as vasospasm, perforation, and dissection, sometimes occurs,” write the investigators, led by Naoko Funatsu,, MD (University of Tsukuba, Tsukuba, Japan). In addition to frank injury to the vessel wall, they say, “it was thought that angiographically occult vessel ruptures caused by mechanical stretch on retrieval could be associated with vessel wall permeability impairment and blood-CSF barrier disruption after SR thrombectomy,” they suggest.
Funatsu et al say the presence of collagen fibers in specimens retrieved by thrombectomy might be surrogate markers of histological vascular injury. To determine how often such fibers are present and whether they have clinical significance, the investigators conducted histopathological assessment of 150 specimens of thrombi retrieved from 101 patients (47 women, mean age 74.9 years) who were treated endovascularly for acute stroke between November 2013 and April 2016. Overall, 42 patients were treated using the Penumbra aspiration catheter, 21 using stent retrievers, and 38 using both. Among these specimens, 76 were retrieved using the Penumbra aspiration catheter (Penumbra Inc, Alameda, CA), and 74 with various stent retriever devices.
Vascular wall components, defined as banded collagen fibers with a distinct boundary observed at the rim or outside of the retrieved thrombi, were observed in 24 specimens (16%) from 22 patients.
Factors associated with the presence of vascular-wall components were a low proportion of erythrocyte components, a high proportion of fibrin/platelet components, and a high frequency of the devices reaching distally (ie, the M2 portion of the middle cerebral artery, the P2 portion of the posterior cerebral artery, or more distally). There was also a trend toward a lower rate of complete recanalization among patients whose specimens contained vascular-wall components.
Features Associated With the Presence of Vascular Wall Components
|
|
With Components |
Without Components |
P Value |
|
Ratio of Erythrocyte Components |
41.7 ± 24.8% |
55.0 ± 26.3% |
0.01 |
|
Ratio of Fibrin/Platelet Components |
57.9 ± 24.8% |
44.3 ± 25.7% |
0.01 |
|
Device Reaching Distally (M2/P2 or More Distal) |
75% |
50% |
0.02 |
|
mTICI ≥ 2b Reperfusion |
73% |
89% |
0.06 |
The authors conclude that stent retriever thrombectomy using both aspiration catheters and stent retrievers “caused various vascular injuries.” They recommend that further studies be conducted to evaluate the clinical implications of these findings, which should address the features associated with an increased risk of the presence of vascular-wall components that they identified.
Source:
Funatsu N, Hayakawa M, Hashimoto T, et al. Vascular wall components in thrombi obtained by acute stroke thrombectomy: clinical significance and related factors. J NeuroIntervent Surg. 2018;Epub ahead of print.
Disclosures:
Funatsu reports no relevant conflicts of interest.
