@article {Mereutaneurintsurg-2021-017310, author = {Oana Madalina Mereuta and Mehdi Abbasi and Se{\'a}n Fitzgerald and Daying Dai and Ram Kadirvel and Ricardo A Hanel and Albert J Yoo and Mohammed A Almekhlafi and Kennith F Layton and Josser E Delgado Almandoz and Peter Kvamme and Vitor Mendes Pereira and Babak S Jahromi and Raul G Nogueira and Matthew J Gounis and Biraj Patel and Amin Aghaebrahim and Eric Sauvageau and Parita Bhuva and Jazba Soomro and Andrew M Demchuk and Ike C Thacker and Yasha Kayan and Alexander Copelan and Pouya Nazari and Donald Robert Cantrell and Diogo C Haussen and Alhamza R Al-Bayati and Mahmoud Mohammaden and Leonardo Pisani and Gabriel Martins Rodrigues and Ajit S Puri and John Entwistle and Alexander Meves and Jorge L Arturo Larco and Luis Savastano and Harry J Cloft and David F Kallmes and Karen M Doyle and Waleed Brinjikji}, title = {Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy}, elocation-id = {neurintsurg-2021-017310}, year = {2021}, doi = {10.1136/neurintsurg-2021-017310}, publisher = {British Medical Journal Publishing Group}, abstract = {Background Several animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.Objective To investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.Methods As part of the multicenter STRIP registry, 277 clots from 237 patients were analyzed using Martius Scarlett Blue stain and immunohistochemistry for CD34 (endothelial cells) and smooth muscle actin (smooth muscle cells).Results MT devices used were aspiration catheters (100 cases), stentriever (101 cases), and both (36 cases). VWI was found in 33/277 clots (12\%). There was no significant correlation between VWI and MT device. The degree of damage varied from grade I (mild intimal damage, 24 clots), to grade II (relevant intimal and subintimal damage, 3 clots), and III (severe injury, 6 clots). VWI clots contained significantly more erythrocytes (p=0.006*) and less platelets/other (p=0.005*) than non-VWI clots suggesting soft thrombus material.Thrombolysis correlated with a lower rate of VWI (p=0.04*). VWI cases showed a significantly higher number of passes (2 [1{\textendash}4] vs 1 [1{\textendash}3], p=0.028*) and poorer recanalization outcome (p=0.01*) than cases without VWI.Conclusions Histological markers of VWI were present in 12\% of AIS thrombi, suggesting that VWI might be related to MT. VWI was associated with soft thrombus consistency, higher number of passes and poorer revascularization outcome. There was no significant correlation between VWI and MT device.Data are available from the corresponding author upon reasonable request.}, issn = {1759-8478}, URL = {https://jnis.bmj.com/content/early/2021/08/24/neurintsurg-2021-017310}, eprint = {https://jnis.bmj.com/content/early/2021/08/24/neurintsurg-2021-017310.full.pdf}, journal = {Journal of NeuroInterventional Surgery} }