Distal Embolization in Relation to Radiological Thrombus Characteristics, Treatment Details, and Functional Outcome

Abstract

Background: Distal embolization (DE) is a common complication of endovascular treatment (EVT). We investigated the association of radiological thrombus characteristics and treatment details with DE. Methods: Patients with thin-slice (≤2.5 mm) baseline noncontrast computed tomography and computed tomography angiography from the ESCAPE-NA1 trial (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke) were included. Thrombus annotation was performed manually on coregistered scans by experienced readers. We assessed thrombus location, distance from internal carotid artery terminus, length, perviousness, absolute attenuation, and hyperdense artery sign. In addition, we evaluated balloon guide catheter use during EVT, first-line EVT approach, the number of thrombectomy passes, and prior intravenous thrombolysis administration. DE was defined as the occurrence of emboli distal to the target artery or in new territories during EVT. The association between thrombus characteristics, treatment details, and DE was evaluated using descriptive statistics and multivariable mixed-effects logistic regression, resulting in adjusted odds ratios (aOR) with 95% CI. Interaction between IVT and radiological thrombus characteristics was assessed by adding interaction terms in separate models. Results: In total, 496 out of 1105 (44.9%) ESCAPE-NA1 patients were included. DE was detected in 251 out of 496 patients (50.6%). Patients with DE had longer thrombi (median, 28.5 [interquartile range, 20.8–42.3] mm versus 24.4 [interquartile range, 17.1–32.4] mm; P <0.01). There were no statistically significant differences in the other thrombus characteristics. Factors associated with DE were thrombus length (aOR, 1.02 [95% CI, 1.01–1.04]), balloon guide catheter use (aOR, 0.49 [95% CI, 0.29–0.85]), and number of passes (aOR, 1.24 [95% CI, 1.04–1.47]). In patients with hyperdense artery sign, IVT was associated with reduced odds of DE (aOR, 0.55 [95% CI, 0.31–0.97]), P for interaction=0.04. Conclusions: DE was associated with longer thrombi, no balloon guide catheter use, and more EVT passes. IVT was associated with a reduced risk of DE in patients with hyperdense artery sign. These findings may support treatment decisions on IVT and EVT approaches.

Effect of proximal blood flow arrest during endovascular thrombectomy (ProFATE): Study protocol for a multicentre randomised controlled trial

“…An important outcome measure investigated in this study is the frequency of emboli to distal and new vascular territories. Recent studies have demonstrated poorer functional outcomes amongst patients with distal emboli, and including those with microemboli formed during EVT which are thought to be play a role in microperfusion delay (no-reflow phenomenon) despite successful vessel recanalisation (4,6,32). There is no consensus on the optimal method of identifying emboli to new or distal vascular territories due to limitations in each imaging method (33).…”

“…Recent studies have demonstrated poorer functional outcomes amongst patients with distal emboli, and including those with microemboli formed during EVT which are thought to be play a role in microperfusion delay (no-reflow phenomenon) despite successful vessel recanalisation. 4,6,32 There is no consensus on the optimal method of identifying emboli to new or distal vascular territories due to limitations in each imaging method. 33 We chose to identify emboli to new and distal vascular territories by comparing the pre- and post-EVT angiographic images as opposed to surrogate measures using the susceptibility or diffusion-weighted MR imaging sequence.…”

“…Using balloon guide catheters (BGC) as an adjunctive device during EVT in the anterior circulation allows transient proximal blood flow arrest by inflating the balloon at its tip, and even flow reversal when concomitant aspiration is applied. This is thought to limit distal clot migration or embolisation to new vascular territories during EVT (4)(5)(6).…”

“…This is thought to limit distal clot migration or embolisation to new vascular territories during EVT. 4–6…”

“…This is thought to limit distal clot migration or embolisation to new vascular territories during EVT. [4][5][6] Recent meta-analyses of non-randomised studies have suggested that the use of BGC during EVT leads to improved rates of successful reperfusion, first-pass effect (successful reperfusion after the first pass), procedural time and functional outcomes, particularly in patients treated using the stent-retriever (SR) technique only. 7,8 However, due to the paucity of data, meaningful conclusions could not be drawn for patients treated using BGC with the contact aspiration (CA)-only technique or the combined firstline technique of SR and CA.…”