Correlation between acute ischaemic stroke clot length before mechanical thrombectomy and extracted clot area: Impact of thrombus size on number of passes for clot removal and final recanalization

Abstract

Introduction We assessed the correlation between thrombus size before and after mechanical thrombectomy, measured as length by Computed Tomography Angiography/Non-Contrast Computed Tomography (CTA/NCCT) and Extracted Clot Area, ECA, respectively. We also assessed the influence of thrombus size on the number of passes required for clot removal and final recanalization outcome. Materials and methods Acute ischaemic stroke (AIS) thrombi retrieved by mechanical thrombectomy from 500 patients and data of clot length by CTA/NCCT were collected from three hospitals in Europe. ECA was obtained by measuring the area of the extracted clot. Non-parametric tests were used for data analysis. Results A strong positive correlation was found between clot length on CTA/NCCT and ECA (rho = 0.619,N = 500,P < 0.0001*). Vessel size influences clot length on CTA/NCCT (H2 = 98.6, P < 0.0001*) and ECA (H2 = 105.6,P < 0.0001*), but the significant correlation between CTA/NCCT length and ECA was evident in all vessels. Poorer revascularisation outcome was associated with more passes (H5 = 73.1, P < 0.0001*). More passes were required to remove longer clots (CTA/NCCT; H4 = 31.4, P < 0.0001*; ECA; H4 = 50.2, P < 0.0001*). There was no significant main association between recanalization outcome and length on CTA/NCCT or ECA, but medium sized clots (ECA 20–40 mm2) were associated with least passes and highest revascularisation outcome (N = 500, X2 = 16.2, P < 0.0001*). Conclusion Clot length on CTA/NCCT strongly correlates with ECA. Occlusion location influences clot size. More passes are associated with poorer revascularisation outcome and bigger clots. The relationship between size and revascularisation outcome is more complex. Clots of medium ECA take less passes to remove and are associated with better recanalization outcome than both smaller and larger clots.

S100b in acute ischemic stroke clots is a biomarker for post-thrombectomy intracranial hemorrhages

“…Thrombotic material extracted via mechanical thrombectomy was collected per pass at the hospital venue in separate pots containing 10% formalin and shipped to NUI Galway. A gross photo of each thrombus was taken with a Canon EOS 1300D Camera and the relevant Extracted Clot Area (ECA) was measured and used as an estimate of the extracted clot size, by drawing around each fragment with a specific tool using ImageJ software, as previously reported ( 24 – 27 ). In brief, to measure the Extracted Clot Area (ECA), the gross photo of the extracted clot was opened using ImageJ software, the scale was set and the Polygon tool was used to draw a region of interest around each clot fragment in the gross photo, and summed to give overall ECA for the sample.…”

Does prior administration of rtPA influence acute ischemic stroke clot composition? Findings from the analysis of clots retrieved with mechanical thrombectomy from the RESTORE registry

“…After the endovascular treatment, extracted thrombi were collected per pass and shipped in 10% formalin to NUI Galway, where a gross photo of each was taken with a Canon EOS 1300D Camera. Extracted Clot Area (ECA) was used as an estimate of the size of extracted clot and was measured as previously reported [ 17 , 24 , 25 ]. In brief, to measure the area of a fragment, the gross photo was opened with ImageJ software, the scale was set and the Polygon tool was used to draw a region of interest around the fragment.…”

“…1b). Median RBCs composition was 45 % for bridging-therapy and 44 % for MTalone clots (H1 = 0.018, P = 0.895); median FIB composition was 30 [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]% for bridging-therapy and 29 % for MT alone (H1 = 0.552, P = 0.458); median PTL composition was 16 % for bridging-therapy and 17 [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]% for MT alone (H1 = 0.014, P = 0.905). Further analysis was then performed combining size and histological composition (Fig.…”

Characterization of the ‘White’ Appearing Clots that Cause Acute Ischemic Stroke

“…Occlusion location, clot length and density were assessed prior to MT using computed tomography angiography (CTA; 0.6 mm slice thickness) or non-contrast computed tomography (NCCT; 0.6 mm slice thickness). 9 Stroke etiology was self-reported at each center and classified using the Trial of Org 10172 in Acute Stroke Treatment (TOAST) system: Large Artery Atherosclerosis (LAA), cardioembolic (CE), stroke of other determined etiology and cryptogenic. We defined an aspiration case when only aspiration through a catheter was performed, a stentriever case when a stentriever was used alone or in combination with an aspiration catheter and a rescue-therapy case when the approach was switched during the procedure.…”

“…ImageJ software ((https://imagej.nih.gov/ij/) was utilized to measure total extracted clot area (ECA) of each clot using the gross image of the clot as previously described. 9,10 First the scale was set and then the polygon tool was used to draw a region of interest around a fragment of the clot, and the area of that fragment was measured individually. The total extracted clot area for each case is defined as the sum of the clot area from all clot fragments within a case.…”