Favourable arterial, tissue-level and venous collaterals correlate with early neurological improvement after successful thrombectomy treatment of acute ischaemic stroke.

BACKGROUND AND PURPOSE: Early neurological improvement (ENI) after thrombectomy is associated with better long-term outcomes in patients with acute ischaemic stroke due to large vessel occlusion (AIS-LVO). Whether cerebral collaterals influence the likelihood of ENI is poorly described. We hypothesised that favourable collateral perfusion at the arterial, tissue-level and venous outflow (VO) levels is associated with ENI after thrombectomy. MATERIALS AND METHODS: Multicentre retrospective study of patients with AIS-LVO treated by thrombectomy. Tissue-level collaterals (TLC) were measured on cerebral perfusion studies by the hypoperfusion intensity ratio. VO and pial arterial collaterals (PAC) were determined by the Cortical Vein Opacification Score and the modified Tan scale on CT angiography, respectively. ENI was defined as improvement of ≥8 points or a National Institutes of Health Stroke Scale score of 0 hour or 1 24 hours after treatment. Multivariable regression analyses were used to determine the association of collateral biomarkers with ENI and good functional outcomes (modified Rankin Scale 0-2). RESULTS: 646 patients met inclusion criteria. Favourable PAC (OR: 1.9, CI 1.2 to 3.1; p=0.01), favourable VO (OR: 3.3, CI 2.1 to 5.1; p<0.001) and successful reperfusion (OR: 3.1, CI 1.7 to 5.8; p<0.001) were associated with ENI, but favourable TLC were not (p=0.431). Good functional outcomes at 90-days were associated with favourable TLC (OR: 2.2, CI 1.4 to 3.6; p=0.001), VO (OR: 5.7, CI 3.5 to 9.3; p<0.001) and ENI (OR: 5.7, CI 3.3 to 9.8; p<0.001), but not PAC status (p=0.647). CONCLUSION: Favourable PAC and VO were associated with ENI after thrombectomy. Favourable TLC predicted longer term functional recovery after thrombectomy, but the impact of TLC on ENI is strongly dependent on vessel reperfusion.

Computed tomography-based triage of extensive baseline infarction: ASPECTS and collaterals versus perfusion imaging for outcome prediction.

BACKGROUND: Patients presenting with large baseline infarctions are often excluded from mechanical thrombectomy (MT) due to uncertainty surrounding its effect on outcome. We hypothesized that computed tomography perfusion (CTP)-based selection may be predictive of functional outcome in low Alberta Stroke Program Early CT Score (ASPECTS) patients. METHODS: This was a double-center, retrospective analysis of patients presenting with ASPECTS≤5 who received multimodal admission CT imaging between May 2015 and June 2020. The predicted ischemic core (pCore) was defined as a reduction in cerebral blood flow (rCBF), while mismatch volume was defined using time to maximum (Tmax). The pCore perfusion mismatch ratio (CPMR) was also calculated. These parameters (pCore, mismatch volume, and CPMR), as well as a combined radiological score consisting of ASPECTS and collateral status (ASCO score), were tested in logistic regression and receiver operating characteristic (ROC) analyses. The primary outcome was favorable modified Rankin Scale (mRS) at discharge (≤3). RESULTS: A total of 113 patients met the inclusion criteria. The median ischemic core volume was 74.1 mL (IQR 43.8-121.8). The ASCO score was associated with favorable outcome at discharge (aOR 3.7, 95% CI 1.8 to 10.7, P=0.002), while no association was observed for the CTP parameters. A model including the ASCO score also had significantly higher area under the curve (AUC) values compared with the CTP-based model (0.88 vs 0.64, P=0.018). CONCLUSIONS: The ASCO score was superior to the CTP-based model for the prediction of good functional outcome and could represent a quick, practical, and easily implemented method for the selection of low ASPECTS patients most likely benefit from MT.

Computed tomography findings in patients with primarily unknown causes of severe or recurrent epistaxis.

OBJECTIVE: In addition to rhinoscopy, computed tomography of paranasal sinuses (CT) may be performed on patients with primary unknown cause of severe epistaxis (SE) or recurrent epistaxis (RE) to further assess the potential cause of bleeding. The aim of this study was to evaluate CT findings during the work-up of intractable epistaxis patients. METHODS: 6937 patients were treated in our emergency department with acute epistaxis between 2009-2018. 304/6937 patients underwent CT and rhinoscopy due to intractable SE or RE. 33 patients presented with head trauma prior to epistaxis and were excluded from the final analysis. In 271 cases the primary causes of SE (n = 252) or RE (n = 19) remained unknown. Two observers retrospectively evaluated CT scans for potential sources of epistaxis. Disagreement was settled by consensus. CT and rhinoscopy findings were compared. RESULTS: In 247/271 (91.1%) SE patients no related pathology was found on CT. A possible cause for epistaxis was found in all RE patients, but only in 5/252 (1.9%) patients with SE. Most tumours (10/11) and inflammatory conditions (9/10) were found in patients with RE. In three SE cases, a tumour was suspected on CT, from which two suspicions were refuted during rhinoscopy. CT revealed 10 cases of inflammatory conditions of the sinus and anatomical variant as potential cause of bleeding. CONCLUSION: For patients with unknown causes of epistaxis, supplementary CT imaging may be a useful diagnostic add-on to rhinoscopy in the event of RE, tumour suspicion or inflammation of the paranasal sinuses. However, in most cases of first-time SE, CT does not necessarily add to the diagnosis. In these cases, the marginal benefit of CT needs to be weighed carefully against its risks.

Clinical benefit of thrombectomy in stroke patients with low ASPECTS is mediated by oedema reduction.

The impact of endovascular vessel recanalization on patients with a low initial Alberta Stroke Program Early Computer Tomography Score (ASPECTS) is still uncertain. We hypothesized that vessel recanalization leads to an improvement in mortality and degree of disability by reducing brain oedema and malignant mass effect. In this multicentre observational study, patients with acute ischaemic stroke due to large vessel occlusion in the anterior circulation and an ASPECTS of ≤ 5 were analysed. Patients were assembled into two groups: successful vessel recanalization (thrombolysis in cerebral infarctions, TICI scale 2b/3) or persistent vessel occlusion (no endovascular procedure or TICI scale 0-2a). Observers were blinded to clinical data. Net water uptake within brain infarct, a quantitative biomarker based on CT densitometry, was used to quantify oedema in admission and follow-up CT and Δ-water uptake was calculated as difference between water uptake at both time points. Occurrence of malignant infarctions and secondary parenchymal haemorrhage was documented. Furthermore, modified Rankin scale score at 90 days was used for functional outcome. We included 117 patients admitted between March 2015 and August 2017 in three German stroke centres: 71 with persistent vessel occlusion and 46 with successful recanalization. The mean water uptake in the admission imaging was not different between both groups: 10.0% (±4.8) in patients with persistent vessel occlusion and 9.0% (±4.8) in patients with vessel recanalization (P = 0.4). After follow-up CT, the mean Δ-water uptake was 16.0% (±7.5) in patients with persistent vessel occlusion and 8.0% (±5.7) in patients with vessel recanalization (P < 0.001). Successful reperfusion was independently associated with a lowered Δ-water uptake of 8.0% (95% confidence interval, CI: -10.5 to -5.3%; P < 0.001) and lowered modifed Rankin scale score after 90 days of 1.5 (95% CI: -2.2 to -0.8; P < 0.001). The prevalence of malignant infarctions was 44.3% in patients with persistent vessel occlusion and 26.1% in patients with vessel recanalization. There was no significant difference for secondary haemorrhage in both groups (P = 0.7). In conclusion, successful recanalization in patients with low initial ASPECTS resulted in a significant reduction of oedema formation and was associated with a decreased prevalence of malignant infarctions and an improvement of clinical outcome.

Reasons for failed endovascular recanalization attempts in stroke patients.

PURPOSE: Mechanical thrombectomy (MT) is a highly effective therapy in patients with acute ischemic stroke due to large vessel occlusion (LVO). However, complete recanalization of the occluded vessel cannot be achieved in all patients, leading to poor clinical outcome. We analyzed the reasons for failed recanalization to help direct future improvements in therapy. METHODS: 648 consecutive stroke patients with LVO and an MT attempt were retrospectively analyzed for none or minimal recanalization, assessed according to the Thrombolysis in Cerebral Infarction (TICI) score (0/1). Procedural parameters were evaluated in a standardized approach. Among other variables, number of retrieval attempts, devices, duration of the intervention, and rescue methods were analyzed. RESULTS: TICI 0/1 was observed in 72/648 patients (11%). In these patients, the thrombus could not be reached in 21% (n=15/72), was reached but not passed in 21% (n=15/72), and was reached and passed in 58% (n=42/72). Only a minor degree of initial recanalization was achieved in 19% (n=8/42) of patients with a reached occlusion during the course of the intervention. Furthermore, a higher number of passes with a single retriever device led to significant prolongation of the intervention. Therefore, major reasons for failed endovascular recanalization were difficult anatomical access and hard or resistant occlusions that might reflect hard thrombi or pre-existing atherosclerotic stenosis. Procedural complications such as dissection or perforation played a minor role. CONCLUSION: In stroke patients with failed MT attempts, approximately 60% of occlusions can be passed. In such cases, rescue therapy might be considered to improve recanalization and clinical outcome. Further development of access devices might help in the remaining cases where the microcatheter could not be manipulated to or through the occlusion.