CT angiography in an acute stroke protocol: correlation between occlusion site and outcome of intravenous thrombolysis

Staged Endovascular Treatment for Symptomatic Occlusion Originating From the Intracranial Vertebral Arteries in the Early Non-acute Stage

Background: The ideal treatment for patients who survive from acute vertebrobasilar artery occlusion but develop aggressive ischemic events despite maximal medical therapy in the early non-acute stage is unknown. This paper reports the technical feasibility and outcome of staged endovascular treatment in a series of such patients with symptomatic intracranial vertebral artery occlusion.

Methods: Ten consecutive patients who presented with aggressive ischemic events in the early non-acute stage of intracranial vertebral artery occlusion from Jan 2015 to Nov 2020 were retrospectively reviewed. Among them, eight male and two female patients with a mean age of 66.7 years developed aggressive ischemic events, and the NIHSS score was elevated by a median of 7 points despite medical therapy. All patients received staged endovascular treatment 4–21 days from onset, at an average of 11 days. The strategy of staged treatment was as follows: first, a microwire was passed through the portion of the occlusion, which was then dilated with balloon inflation to maintain the perfusion above TICI grade 2b. Then, with the use of antiplatelet drugs, the residual intravascular thrombus was gradually eliminated by the continuous perfusion and an activated fibrinolytic system, leaving the residual stenosis. A second stage of angioplasty with stent implantation was subsequently performed if residual stenosis was ≥50%. The NIHSS scores and mRS scores were compared between pre- and post-endovascular treatment groups and in the follow-up period.

Results: Technical success was achieved in 9 patients who received staged endovascular treatment (perforation occurred in one patient during the first stage). The NIHSS scores were significantly improved, with a median score 7 points lower on discharge compared with the scores for the most severe status. Favorable outcomes with mRS score ≤ 2 were achieved in 7 and 9 patients at the 3-month follow-up and the latest follow-up, respectively, which was better than the preoperative status.

Conclusion: Staged endovascular treatment might be a safe, efficient, and viable option in carefully selected patients with symptomatic intracranial vertebral artery occlusion in the early non-acute stage. However, this needs to be confirmed by further investigation, preferably in a large, controlled setting.

Cerebral attenuation on single-phase CT angiography source images: Automated ischemia detection and morphologic outcome prediction after thrombectomy in patients with ischemic stroke

Objectives

Stroke triage using CT perfusion (CTP) or MRI gained importance after successful application in recent trials on late-window thrombectomy but is often unavailable and time-consuming. We tested the clinical value of software-based analysis of cerebral attenuation on Single-phase CT angiography source images (CTASI) as CTP surrogate in stroke patients.

Methods

Software-based automated segmentation and Hounsfield unit (HU) measurements for all regions of the Alberta Stroke Program Early CT Score (ASPECTS) on CTASI were performed in patients with large vessel occlusion stroke who underwent thrombectomy. To normalize values, we calculated relative HU (rHU) as ratio of affected to unaffected hemisphere. Ischemic regions, regional ischemic core and final infarction were determined on simultaneously acquired CTP and follow-up imaging as ground truth. Receiver operating characteristics analysis was performed to calculate the area-under-the-curve (AUC). Resulting cut-off values were used for comparison with visual analysis and to calculate an 11-point automated CTASI ASPECTS.

Results

Seventy-nine patients were included. rHU values enabled significant classification of ischemic involvement on CTP in all ten regions of the ASPECTS (each p<0.001, except M4-cortex p = 0.002). Classification of ischemic core and prediction of final infarction had best results in subcortical regions but produced lower AUC values with significant classification for all regions except M1, M3 and M5. Relative total hemispheric attenuation provided strong linear correlation with CTP total ischemic volume. Automated classification of regional ischemia on CTASI was significantly more accurate in most regions and provided better agreement with CTP cerebral blood flow ASPECTS than visual assessment.

Conclusions

Automated attenuation measurements on CTASI provide excellent performance in detecting acute ischemia as identified on CTP with improved accuracy compared to visual analysis. However, value for the approximation of ischemic core and morphologic outcome in large vessel occlusion stroke after thrombectomy was regionally dependent and limited. This technique has the potential to facilitate stroke imaging as sensitive surrogate for CTP-based ischemia.

Computed tomography perfusion and computed tomography angiography for prediction of clinical outcomes in ischemic stroke patients after thrombolysis

Cerebral blood perfusion and cerebrovascular lesions are important factors that can affect the therapeutic efficacy of thrombolysis. At present, the majority of studies focus on assessing the accuracy of lesion location using imaging methods before treatment, with less attention to predictions of outcomes after thrombolysis. Thus, in the present study, we assessed the efficacy of combined computed tomography (CT) perfusion and CT angiography in predicting clinical outcomes after thrombolysis in ischemic stroke patients. The study included 52 patients who received both CT perfusion and CT angiography. Patients were grouped based on the following criteria to compare clinical outcomes: (1) thrombolytic and non-thrombolytic patients, (2) thrombolytic patients with CT angiography showing the presence or absence of a vascular stenosis, (3) thrombolytic patients with CT perfusion showing the presence or absence of hemodynamic mismatch, and (4) different CT angiography and CT perfusion results. Short-term outcome was assessed by the 24-hour National Institution of Health Stroke Scale score change. Long-term outcome was assessed by the 3-month modified Rankin Scale score. Of 52 ischemic stroke patients, 29 were treated with thrombolysis and exhibited improved short-term outcomes compared with those without thrombolysis treatment (23 patients). Patients with both vascular stenosis and blood flow mismatch (13 patients) exhibited the best short-term outcome, while there was no correlation of long-term outcome with CT angiography or CT perfusion findings. These data suggest that combined CT perfusion and CT angiography are useful for predicting short-term outcome, but not long-term outcome, after thrombolysis.

Association of Cortical Vein Filling with Clot Location and Clinical Outcomes in Acute Ischaemic Stroke Patients

Delay in cortical vein filling during the late-venous phase (delayed-LCVF) is characterized by opacification of cerebral veins despite contrast clearance from contralateral veins on dynamic computed tomography angiography (dCTA) in acute ischemic stroke (AIS) patients. The aim of the study was to investigate the associations of delayed-LCVF with clot location, reperfusion status at 24 hours, and 90-days functional outcome in AIS patients who received reperfusion therapy. A prospective cohort of AIS patients treated with intravenous thrombolysis was studied. Groupwise comparison, univariate, and multivariate regression analyses were used to study the association of delayed-LCVF with clot location and clinical outcomes. Of 93 patients (mean age = 72 ± 12 years) with hemispheric AIS included in the study, 46 (49%) demonstrated delayed-LCVF. Patients with delayed-LCVF demonstrated a significantly higher proportion of proximal occlusion (72% vs 13%, P =< 0.0001), and poor reperfusion at 24 hours (41% vs 11%, P = 0.001). The proportion of poor functional outcome at 90 days was not significantly different (22/56 (48%) vs 17/61 (36%), P = 0.297). The appearance of delayed-LCVF on baseline dCTA may be a surrogate for large vessel occlusion, and an early marker for poor 24-hour angiographic reperfusion.

Stent Retriever Thrombectomy of Small Caliber Intracranial Vessels Using pREset LITE: Safety and Efficacy

Purpose

Few devices are approved for thrombectomy of distal vessel branches, and clinical experience is limited. Here we report our experience with pREset LITE for thrombectomy of small intracranial vessels.

Methods

From an institutional database we selected consecutive patients treated with pREset LITE for an occlusion of small (≤ 2 mm), intracranial target vessels. Recanalization success was measured by applying the modified Thrombolysis In Cerebral Infarction (mTICI) score. To assess safety, we recorded device-related procedural events and potentially device-related hemorrhages on follow-up imaging. Infarcts in the dependent territory served as a measure for efficacy.

Results

Of 536 patients treated between August 2013 and March 2015, 76 met the inclusion criteria. pREset LITE was used in 90 branches with an average diameter of 1.6 mm (1.3–2.0 mm). An mTICI score ≥ 2b was achieved in 70.0 %. Procedural events consisted of 5.6 % significant vasospasm, 2.2 % suspected dissections, 2.2 % downstream emboli, and 1.1 % self-limiting extravasations. On posttreatment imaging 2.2 % parenchymal hemorrhages type I (PHI) and 13.3 % focal subarachnoid hemorrhage (SAH) were potentially device related, but all of these events remained asymptomatic. After successful recanalization, 33.3 % developed no ischemia in the dependent territory while 41.7 % developed a partial infarct, and 25 % developed a complete infarct. Successful recanalization significantly increased the chance to develop no or only partial infarct compared with a complete infarction (p = 0.003, p = 0.013).

Conclusions

Thrombectomy of small vessels with pREset LITE is feasible with good recanalization and reasonable safety margins. Successful recanalization significantly reduces the risk of infarction in the dependent territory. The impact on the overall clinical outcome remains to be determined.

Mechanical thrombectomy versus systemic thrombolysis in MCA stroke: a distance to thrombus-based outcome analysis

BACKGROUND

Acute ischemic stroke due to occlusion of the middle cerebral artery (MCA) has a poor outcome. The distance to thrombus (DT) from the carotid T can predict the outcome after intravenous thrombolysis (IVT). With a DT <16 mm, fewer than 50% of patients treated with IVT have a favorable outcome.

OBJECTIVE

To compare stent retriever-based endovascular mechanical thrombectomy (MT) plus additional IVT (IVT-MT) with IVT alone.

MATERIALS AND METHODS

Patients with MCA occlusion proved by CT angiography with a DT <16 mm, treated with either IVT alone or with stent retriever-based endovascular IVT-MT, were included in this study. Changes in National Institutes of Health Stroke Scale (NIHSS), the 7-day NIHSS, and the 90-day modified Rankin Scale (mRS) scores were analyzed by treatment modality.

RESULTS

Of 621 patients, 87 fulfilled all inclusion criteria. Fifty-nine patients were treated with IVT and 28 with IVT-MT. Although patients treated with IVT-MT had had significantly more severe strokes than those treated with IVT alone (initial NIHSS 16 (7-18) vs 14 (5-22); p=0.032), both the short- and long-term outcomes were significantly better in this patient group (NIHSS improvement on day 7: 10.9±6.3 vs 6.7±6.7; p=0.008/90-day mRS: 2 (0.75-2.5) vs 4 (2-6); p=0.003).

CONCLUSIONS

In patients with an acute MCA occlusion and a DT <16 mm, IVT-MT leads to a significantly better outcome than in patients treated with IVT alone.

Mechanical embolectomy for acute ischemic stroke in the anterior cerebral circulation: the Gothenburg experience during 2000-2011

BACKGROUND AND PURPOSE

Intra-arterial treatment of proximal occlusions in the cerebral circulation have become an important tool in the management of acute ischemic stroke. Our goal was to evaluate the safety and efficacy of intra-arterial acute ischemic stroke treatment performed in our institution in consecutive patients with anterior circulation occlusion during 2000-2011.

MATERIALS AND METHODS

We identified, in our data base, 156 consecutive cases with anterior acute ischemic stroke treated intra-arterially during 2000-2011. Stroke severity was defined according to the National Institutes of Health Stroke Scale, the results of the procedure were defined according to the modified Thrombolysis in Cerebral Infarction score, and clinical outcome was defined according to the modified Rankin scale, with favorable outcome ≤2 at 90 days.

RESULTS

The mean admission NIHSS score was 19.4 (median, 20), with a mean time from stroke onset to groin puncture of 197 minutes (median, 171 minutes). The embolectomy tool of choice was the Amplatz GooseNeck snare (83%). Successful recanalization (modified TICI 2b +3) was seen in 74% of cases. A mRS ≤ 2 at 90 days was seen in 42% with a mortality rate of 17% and symptomatic intracerebral hemorrhage in 4%.

CONCLUSIONS

A high recanalization rate was obtained with the Amplatz GooseNeck snare without any device-related complications. Favorable outcome, mortality, and symptomatic intracerebral hemorrhage are comparable with results of newer embolectomy devices.