RT Journal Article SR Electronic T1 Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy JF Journal of NeuroInterventional Surgery JO J NeuroIntervent Surg FD BMJ Publishing Group Ltd. SP neurintsurg-2021-017310 DO 10.1136/neurintsurg-2021-017310 A1 Oana Madalina Mereuta A1 Mehdi Abbasi A1 Seán Fitzgerald A1 Daying Dai A1 Ram Kadirvel A1 Ricardo A Hanel A1 Albert J Yoo A1 Mohammed A Almekhlafi A1 Kennith F Layton A1 Josser E Delgado Almandoz A1 Peter Kvamme A1 Vitor Mendes Pereira A1 Babak S Jahromi A1 Raul G Nogueira A1 Matthew J Gounis A1 Biraj Patel A1 Amin Aghaebrahim A1 Eric Sauvageau A1 Parita Bhuva A1 Jazba Soomro A1 Andrew M Demchuk A1 Ike C Thacker A1 Yasha Kayan A1 Alexander Copelan A1 Pouya Nazari A1 Donald Robert Cantrell A1 Diogo C Haussen A1 Alhamza R Al-Bayati A1 Mahmoud Mohammaden A1 Leonardo Pisani A1 Gabriel Martins Rodrigues A1 Ajit S Puri A1 John Entwistle A1 Alexander Meves A1 Jorge L Arturo Larco A1 Luis Savastano A1 Harry J Cloft A1 David F Kallmes A1 Karen M Doyle A1 Waleed Brinjikji YR 2021 UL http://jnis.bmj.com/content/early/2021/08/24/neurintsurg-2021-017310.abstract AB 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 [1–4] vs 1 [1–3], 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.