Mechanical thrombectomy in MCA-mainstem occlusion in patients with low NIHSS scores

Cineangiography versus standard digital subtraction angiography in mechanical thrombectomy: lowering the radiation exposure without sacrificing the outcome

BACKGROUND

Endovascular thrombectomy has become a standard procedure for the treatment of acute ischemic stroke caused by large vessel occlusion. Radiation exposure to the patient and operators during mechanical thrombectomy procedures is a concern.

METHODS

The use of a high frames per second unmasked protocol-cineangiography (CINE)-derived from cardiac intervention could mitigate radiation exposure without sacrificing procedural and clinical outcomes.

RESULTS

The analysis of a prospective-maintained monocentric database of 131 patients who underwent mechanical thrombectomy (65 with the CINE protocol and 66 with the conventional digital subtraction angiography (DSA) protocol) showed a significant reduction in radiation exposure for both air kerma (AK) and dose-area product (DAP) indicators (AK 463.7 mGy vs 772 mGy, P<0.01; DAP 41.35 Gy/cm2 CINE vs 83.77 Gy/cm2 DSA, P<0.01), with no differences regarding both safety and efficacy outcomes (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b 78.4% CINE and 81.5% DSA, P=0.79; overall complications rate both intracranial and extracranial 23% CINE and 19.6% DSA, P=0.65). There were no significant differences in post-thrombectomy radiographic hemorrhagic conversion rate (P=0.77) or functional independence on discharge defined as modified Rankin Scale score ≤2 (P=0.39). A post-hoc image assessment of vessel point occlusion and recanalization mTICI score performed by three experienced interventional neuroradiologists not involved in the procedure showed a non-significant difference between the two groups regarding occlusion point (0.928 vs 0.953, P=0.31) and recanalization grade (0.814 vs 0.847, P=0.62).

CONCLUSIONS

Our initial experience demonstrated that reduction of the quality of CINE images caused no modifications in safety and efficacy and should fit within the context of diagnostic requests in an intracranial revascularization procedure.

Outcomes after endovascular mechanical thrombectomy for low compared to high National Institutes of Health Stroke Scale (NIHSS): A multicenter study

OBJECTIVE

The role of endovascular mechanical thrombectomy (MT) in patients presenting with "minor" stroke is uncertain. We aimed to compare outcomes after MT for ischemic stroke patients presenting with National Institutes of Health Stroke Scale (NIHSS) 5 and - within the low NIHSS cohort - identify predictors of a favorable outcome, mortality, and symptomatic intracranial hemorrhage (ICH).

METHODS

We retrospectively analyzed a prospectively maintained, international, multicenter database.

RESULTS

The study cohort comprised a total of 7568 patients from 29 centers. NIHSS was low (<5) in 604 patients (8%), and > 5 in 6964 (92%). Patients with low NIHSS were younger (67 + 14.8 versus 69.6 + 14.7 years, p < 0.001), more likely to have diabetes (31.5% versus 26.9%, p = 0.016), and less likely to have atrial fibrillation (26.6% versus 37.6%, p < 0.001) compared to those with higher NIHSS. Radiographic outcomes (TICI > 2B 84.6% and 84.3%, p = 0.412) and complication rates (8.1% and 7.2%, p = 0.463) were similar between the low and high NIHSS groups, respectively. Clinical outcomes at every follow up interval, including NIHSS at 24 h and discharge, and mRS at discharge and 90 days, were better in the low NIHSS group, however patients in the low NIHSS group experienced a relative decline in NIHSS from admit to discharge. Mortality was lower in the low NIHSS group (10.4% versus 24.5%, p < 0.001).

CONCLUSIONS

Relative to patients with high NIHSS, MT is safe and effective for stroke patients with low NIHSS, and it is reasonable to offer it to appropriately selected patients presenting with minor stroke symptoms. Our findings justify efforts towards a randomized trial comparing MT versus medical management for patients with low NIHSS.

Assessing the Efficacy of Mechanical Thrombectomy in Patients with an NIHSS < 6 Presenting with Proximal Middle Cerebral Artery Vessel Occlusion as Compared to Best Medical Management

BACKGROUND AND PURPOSE

Minor acute ischemic stroke (AIS) patients-defined by an NIHSS score < 6-presenting with proximal middle cerebral artery large vessel occlusions (MCA-LVO) is a subgroup for which treatment is still debated. Although these patients present with minor symptoms initially, studies have shown that several patients afflicted with MCA-LVO in this subgroup experience cognitive and functional decline. Although mechanical thrombectomy (MT) is the standard of care for patients with an NIHSS score of 6 or higher, treatment in the minor stroke subgroup is still being explored. The purpose of this preliminary study is to report our center's experience in evaluating the potential benefit of mechanical thrombectomy (MT) in minor stroke patients when compared to medical management (MM).

METHODS

We performed a retrospective study with two comprehensive stroke centers within our hospital enterprise of consecutive patients presenting with minor AIS secondary to MCA-LVO (defined as M1 or proximal M2 segments of MCA). We subsequently evaluated patients who received MT versus those who received MM.

RESULTS

Between January 2017 and July 2021, we identified 46 AIS patients (11 treated with MT and 35 treated with MM) who presented with an NIHSS score < 6 secondary to MCA-LVO (47.8% 22/46 female, mean age 62.3 years, range 49-75 years). MT was associated with a significantly lower mRS at 90 days (median: 1.0 [IQR 0.0-2.0] versus 3.0 [IQR 1.0-4.0], p = <0.001), a favorable NIHSS shift (-4.0 [IQR -10.0--2.0] versus 0.0 [IQR -2.0-1.0], p = 0.002), favorable NIHSS shift dichotomization (5/11, 45.5% versus 3/35, 8.6%, p = 0.003) and favorable mRS dichotomization (7/11, 63.6% versus 14/35, 40.0%, p = 0.024).

CONCLUSIONS

In our center's preliminary experience, for AIS patients presenting with an NIHSS score < 6 secondary to MCA-LVO, MT may be associated with improved clinical outcomes when compared to MM only.

Mothership vs. drip-and-ship: evaluation of initial treatment strategies for acute ischemic stroke in a well-developed network of specialized hospitals

PURPOSE

Two strategies of initial patient care exist in endovascular thrombectomy (ET) depending on the site of initial admission: the mothership (MS) and drip-and-ship (DnS) principles. This study compares both strategies in regard to patient outcome in a local network of specialized hospitals.

METHODS

Two-hundred-and-two patients undergoing ET in anterior circulation ischemic stroke between June 2016 and May 2018 were enrolled. Ninety two patients were directly admitted to our local facility (MS), One-hundred-and-ten were secondarily referred to our facility. Group comparisons between admission strategies in three-months modified Rankin Scale (mRS), Maas Score and Alberta-Stroke-Program-Early-computed-tomography-score (ASPECTS), National-Institutes-of-Health-Stroke-Scale (NIHSS), age and onset-to-recanalization-time were performed. Correlation between admission strategy and mRS was calculated. A binary logistic regression model was computed including mRS as dependent variable.

RESULTS

There were neither significant group differences in three-months mRS between MS and DnS nor significant correlations. Patients tended to achieve a better outcome with DnS. Collateralization status differed between MS and DnS (p = 0.003) with better collateralization in DnS. There were no significant group differences in NIHSS or ASPECTS but in onset-to-recanalization-time (p < 0.001) between MS and DnS. Binary logistic regression showed a high explanation of variance of mRS but no significant results for admission strategy.

CONCLUSIONS

Functional outcome in patients treated with ET is comparable between the MS and DnS principles. Tendentially better outcome in the DnS subgroup may be explained by selection bias due to a higher willingness to apply ET in patients with worse baseline conditions (e.g. worse collateralization), if patients undergoing MS are already on site.

Clinical effect of successful reperfusion in patients presenting with NIHSS < 6 and large vessel occlusion

PURPOSE

The purpose of this study was to evaluate the impact of reperfusion in patients with large vessel occlusion (LVO) of the anterior circulation and National Institutes of Health Stroke Scale (NIHSS)< 6.

METHODS

It was a retrospective cohort study. The reperfusion grade was determined using the modified thrombolysis in cerebral infarction (TICI) score. The modified Rankin Score (mRS) ≤1 were defined as excellent and (mRS) ≤2 as favorable outcome at 3-month. Meanwhile, the all-cause mortality, intracerebral hemorrhage, and complications were recorded. Multivariate logistic regression analyses were performed to evaluate outcomes.

RESULTS

Seventy-six patients (86.4%) achieved reperfusion (TICI2B/3). Excellent outcome was achieved in 62 (70.5%) and favorable outcome in 69 (78.4%). All-cause death occurred in 2 (2.3%). The rate of excellent outcome in patients with TICI0,1,2A was 41.7%, with TICI2B 69.2%, and with TICI3 78.0% (p < 0.05). In a multivariate logistic regression analysis related to excellent outcome, the OR(95% CI) was 5.68(1.35,23.95) for TICI3; the test for linear trend by entering categorical variables as continuous variables in the adjusted model (p for trend=0.02<0.05), defining TICI0,1,2A as reference. Subgroup analyses showed without intravenous thrombolysis (IVT) (OR, 14.29; 95% CI, 1.76-116.37) and with middle cerebral artery (MCA) occlusion (OR, 7.97; 95% CI,1.26-50.32), the excellent outcome further improved with TICI3. Findings were similar in favorable outcome.

CONCLUSIONS

Our results indicated that successful reperfusion was intensely connected with better functional outcomes for patients with LVO presenting with NIHSS<6 in the anterior circulation, especially MCA occlusion and pretreatment without IVT.

Mechanical Thrombectomy in Patients Presenting with NIHSS Score <6: A Safety and Efficacy Analysis

BACKGROUND AND OBJECTIVES

Groundbreaking trials have shown the tremendous efficacy of mechanical thrombectomy for large vessel occlusions. Currently, mechanical thrombectomy is limited to patients with NIHSS scores ≥6. We investigated the feasibility and safety of MT in patients presenting with NIHSS scores <6.

MATERIALS AND METHODS

A retrospective review of patient who presented with acute ischemic stroke due to large vessel occlusion with an NIHSS score <6 between 2015 - 2021. The patients were then divided into two groups: those who received mechanical thrombectomy and those who did not.

RESULTS

Among 83 patients, 41 received a mechanical thrombectomy while 42 received medical treatment only. The mean age in the mechanical thrombectomy group was 66 years versus 60 years in the medical group (p = 0.06). Risk factors for stroke did not differ significantly between both groups. 14 patients (34.1%) in the mechanical thrombectomy group and 20 (47.6%) in the medical group received tissue plasminogen activator. No significant difference in clinical improvement (NIHSS) at discharge (p=0.85) or the mRS score at 90 days (p = 0.15) was noted. Mechanical thrombectomy was associated with smaller infarct size (p=0.04) and decreased mortality (p=0.03).

CONCLUSIONS

Mechanical thrombectomy is safe and effective for patients who present with large vessel occlusions and low initial NIHSS scores. Therefore, the decision to offer the patient mechanical thrombectomy or not should not be decided by NIHSS score alone. Rather, the decision should be multifactorial with the aim of maximizing the patients' outcomes.

Outcomes after Thrombectomy for Minor Stroke: A Meta-Analysis

PURPOSE

To determine the outcomes after mechanical thrombectomy (MT) versus medical management in patients with minor stroke symptomatology.

METHODS

A meta-analysis was performed for studies reporting outcomes after MT, either as stand-alone therapy or with intravenous thrombolysis in patients with minor stroke and large-vessel occlusion.

RESULTS

Fourteen studies with 2134 patients met the selection criteria and were included. Two studies compared immediate thrombectomy versus best medical management (with rescue thrombectomy) and the odds ratios of excellent outcomes, good outcomes, mortality and incidence of symptomatic intracranial hemorrhage (sICH) after immediate thrombectomy versus best medical management were 1.07 (95% confidence interval [CI] 0.93-1.22%), 1.15 (95% CI 1.05-1.25), 0.65 (95% CI 0.30-1.38), and 2.89 (95% CI 0.82-10.13), respectively. Among the 8 studies that compared MT outcomes versus medical management (without thrombectomy), odds ratios of excellent outcomes, good outcomes, mortality, and incidence of sICH after MT versus medical management were 0.98 (95% CI 0.89-1.07), 0.94 (95% CI 0.89-1.00), 1.61 (95% CI 1.08-2.41), and 2.59 (95% CI 1.35-4.96), respectively. Among all 14 studies, pooled proportions of excellent outcomes, good outcomes, mortality, and sICH after thrombectomy were 58.7%, 76.2%, 6.82%, and 3.23%, respectively.

CONCLUSIONS

Our study shows significant selection bias and heterogeneity in the literature with differences in baseline characteristics (age, stroke severity, prestroke modified Rankin Scale score, side of infarct, vessel and site of occlusion, use of intravenous thrombolysis, criteria for clinical deterioration, and selection bias for rescue MT and rates of reperfusion), emphasizing the need for a randomized controlled trial.

Number of Patients with Ischemic Stroke did not Decline in a Regional Stroke Unit After the Implementation of Mechanical Thrombectomy

OBJECTIVES

Since the implementation of mechanical thrombectomy (MT) in 2015 for patients with ischemic stroke and large-vessel occlusion, the question arose as to whether patients should be primarily admitted to the nearest regional stroke unit (SU) for prompt intravenous thrombolysis (IVT) or to a more distant supraregional SU performing MT, to avoid secondary-transfer delays in MT. Although an evidence-based answer is still lacking, a discrepant discussion with potential consequences for the regional flow of stroke patients arose. We aimed to assess if MT implementation was associated with the number and characteristics of patients with stroke/transient ischemic attack (TIA) admitted to a regional SU not offering endovascular treatment.

MATERIALS AND METHODS

Patients with acute stroke/TIA treated at the Klinikum Main-Spessart Lohr, Germany, in 2013/2014 or 2017/2018 were included in this retrospective study. Data were derived from the clinical information system and mandatory stroke quality assessment. We assessed the catchment area using a region-based approach. For each region, the number of patients treated in our hospital, including data regarding clinical severity, demographic characteristics, and changes over time, were analyzed.

RESULTS

The number of patients with acute stroke/TIA increased from 890 (2013/2014) to 1016 (2017/2018). Aggregated demographic and clinical data of the whole catchment area showed no differences between 2013/2014 and 2017/2018 (P > 0.05) besides duration of hospitalization (P < 0.01), IVT rate (P < 0.01), and secondary transfer for MT. A region-based analysis revealed an increase in younger and more severely affected patients admitted from the periphery of the catchment area between 2013/2014 and 2017/2018.

CONCLUSION

Despite the implementation of MT in the supraregional SUs around our regional SU (not offering MT), more patients with stroke/TIA were admitted to our hospital, especially younger and more severely affected patients, from the border regions of the catchment area.

More expansive horizons: a review of endovascular therapy for patients with low NIHSS scores

While the landmark 2015 stroke trials demonstrated that endovascular therapy (EVT) was superior to medical management for the treatment of acute ischemic stroke due to large vessel occlusion, the efficacy of EVT for patients presenting with a low NIHSS score remains undetermined. We conducted a review of the EVT low National Institutes of Health Stroke Scale (NIHSS) stroke literature, identifying 24 quantitative and six qualitative publications. Details of study designs and outcome were extracted and critically discussed.All identified qualitative studies were retrospective. There was significant study design heterogeneity, with 18 unique study designs between the 24 identified quantitative manuscripts. Study investigations included low NIHSS EVT feasibility (n=6), EVT versus best medical management (BMM; n=10), EVT versus intravenous therapy (IVT, n=3), and low NIHSS score versus high NIHSS score (n=3). From single-arm EVT feasibility studies, the reported ranges of modified Thrombolysis in Cerebral Infarction and symptomatic intracranial hemorrhage were 78-97% and 0-10%, respectively. The EVT versus BMM literature had heterogeneous results with 40% reporting benefit with EVT and 60% reporting neutral findings. None of the studies comparing EVT with IVT reported a difference between the two revascularization therapies. The four identified meta-analyses had incongruent inclusion criteria and conflicting results. Two randomized trials are currently investigating EVT in patients with a low NIHSS score. Selected meta-analyses do suggest a potential benefit of EVT over BMM; however, current and future randomized clinical trials will better elucidate the efficacy of EVT in this patient population.

Endovascular Treatment Versus Best Medical Therapy in Acute Ischemic Stroke Patients with Mild Symptoms

BACKGROUND

The benefit of endovascular treatment (EVT) for acute ischemic stroke patients with mild deficits is unknown. We sought to evaluate the natural history of patients with a low National Institute of Health Stroke Score (NIHSS) and an intracranial occlusion.

METHODS

We included patients with a computed tomography angiogram-proven intracranial arterial occlusion who presented within 24 hours of symptom onset with an NIHSS of ≤6. We compared outcomes of patients who were treated with EVT and those who were not by performing propensity score-matched analysis. Primary outcome was modified Rankin score (mRS) at 90 days.

RESULTS

A total of 66 patients were included: 38 were men (57.6%) with a median age of 69 (interquartile range [IQR], 57-79.5) years. Median NIHSS was 3 (IQR, 2-5). Median time from symptom onset to presentation was 2.87 hours (IQR, 1.3-5.9). Forty of the total cohort underwent best medical therapy alone (60.6%), whereas 26 underwent EVT (39.4%). Nineteen of the 26 patients who underwent EVT had a good clinical outcome (mRS ≤2) (73.1%), compared with 29 of 40 best medical therapy patients (72.5%) (odds ratio, 0.833 with 95% confidence interval, 0.263-2.631; P = 0.755). Following propensity score adjustment there was a tendency toward lower mRS following EVT (P = 0.051).

CONCLUSIONS

Despite the higher number of proximal occlusions in the EVT group, overall outcomes were similar, with >70% of patients in each cohort having a good outcome at 90 days.

Real-world effects of late window neurothrombectomy: procedure rates increase without night-time bias

INTRODUCTION

With the expansion of the interventional time window for stroke from emergent large vessel occlusion (ELVO), the rate of mechanical thrombectomy (MT) is expected to rise, potentially causing higher burnout rates and requiring hospitals to develop strategies for adequate coverage of these procedures.

METHODS

Neurointerventional physicians at 10 participating stroke centers prospectively recorded time requirements for all MT consultations over 30 consecutive 24-hour call periods, including both false positive consultations and MT procedures, during mid to late 2018. Consult start time, procedure start and end time, and data regarding commute to the hospital and delay in scheduled procedures were collected and compared with those from an identical prospective study performed in 2017.

RESULTS

Data were collected from a total of 300 days of call. A total of 166 procedures were performed (mean 0.55 per day), an increase from 0.32 per day in 2017. Overall mean MT direct time burden during each 24-hour call was 124 min (compared with 85 min in 2017). The percentage of consultations for thrombectomy varied based on time of day, with 87% of consults between the hours of midnight and 04:00 proceeding to thrombectomy compared with 37% between the hours of 16:00 and 20:00.

CONCLUSIONS

MT procedural volumes have increased from one every 5 days in 2016 to one every 2 days in 2018. The highest percentage of consults leading to thrombectomy occur in the early morning hours after midnight. Compared with similar data from 2016 and 2017, call demands continue to escalate, representing a significant demand on neurointerventional teams.

Current concepts in imaging and endovascular treatment of acute ischemic stroke: implications for the clinician

During the last decade, the management of acute ischemic stroke has changed dramatically, from an expectant bedside “wait and see” attitude towards active treatment, thanks to the continuous improvement of new therapeutic options. In addition to the use of intravenous (IV) thrombolysis in emergent large vessel occlusion (ELVO), endovascular therapy (EVT) has proven to be very efficient in selected acute stroke patients. The indications for EVT have progressed from the era of thrombolysis to individual patient profiling. Recently, several indication parameters, e.g., “treatment time window” or “more distal vessel occlusion,” are under debate for adjustment. In this article, we review the imaging strategies in acute stroke and discuss several EVT indication dogmas, which are subject to change.

Systematic evaluation of computed tomography angiography collateral scores for estimation of long-term outcome after mechanical thrombectomy in acute ischaemic stroke

PURPOSE

This study compares computed tomography angiography-based collateral scoring systems in regard to their inter-rater reliability and potential to predict functional outcome after endovascular thrombectomy, and relates them to parenchymal perfusion as measured by computed tomography perfusion.

METHODS

Eighty-four patients undergoing endovascular thrombectomy in anterior circulation ischaemic stroke were enrolled. Modified Tan Score, Miteff Score, Maas Score and Opercular Index Score ratio were assessed in pre-interventional computed tomography angiographies independently by two readers. Collateral scores were tested for inter-rater reliability by weighted-kappa, for correlations with three-months modified Rankin Scale, and their potential to differentiate between patients with favourable (modified Rankin Scale ≤2) and poor outcome (modified Rankin Scale ≥3). Correlations with relative cerebral blood volume and relative cerebral blood flow were tested in patients with available computed tomography perfusion.

RESULTS

Very good inter-rater reliability was found for Modified Tan, Miteff and Opercular Index Score ratio, and substantial reliability for Maas. There were no significant correlations between collateral scores and three-months modified Rankin Scale, but significant group differences between patients with favourable and poor outcome for Maas, Miteff and Opercular Index Score ratio. Miteff and Maas were significant predictors of favourable outcome in binary logistic regression analysis. Miteff best differentiated between both outcome groups in receiver-operating characteristics, and Maas reached highest sensitivity for favourable outcome prediction of 96%. All collateral scores significantly correlated with mean relative cerebral blood volume and relative cerebral blood flow.

CONCLUSIONS

Computed tomography angiography scores are valuable in estimating functional outcome after mechanical thrombectomy and reliable across readers. The more complex scores, Maas and Miteff, show the best performances in predicting favourable outcome.

Clinical effect of successful reperfusion in patients presenting with NIHSS < 8: data from the BEYOND-SWIFT registry

BACKGROUND AND PURPOSE

If patients presenting with large vessel occlusions (LVO) and mild symptoms should be treated with endvoascular treatment (EVT) remains unclear. Aims of this study were (1) assessing the safety and technical efficacy of EVT in patients with NIHSS < 8 as opposed to a comparison group of patients presenting with NIHSS ≥ 8 and (2) evaluation of the clinical effect of reperfusion in patients with NIHSS < 8.

METHODS

Patients included into the retrospective multicenter BEYOND-SWIFT registry (NCT03496064) were analyzed. Clinical effect of achieving successful reperfusion (defined as modified Thrombolysis in Cerebral Infarction grade 2b/3) in patients presenting with NIHSS < 8 (N = 193) was evaluated using multivariable logistic regression analyses (displayed as adjusted Odds Ratios, aOR and 95% confidence intervals, 95%-CI). Primary outcome was excellent functional outcome (modified Rankin Scale, mRS 0-1) at day 90. Safety and efficacy of mechanical thrombectomy in patients with NIHSS < 8 was compared to patients presenting with NIHSS ≥ 8 (N = 1423).

RESULTS

Among patients with NIHSS < 8 (N = 193, 77/193, 39.9% receiving pre-interventional IV-tPA), successful reperfusion was significantly related to mRS 0-1 (aOR 3.217, 95%-CI 1.174-8.816) and reduced the chances of non-hemorrhagic neurological worsening (aOR 0.194, 95%-CI 0.050-0.756) after adjusting for prespecified confounders. In interaction analyses, the relative merits of achieving successful reperfusion were mostly comparable between patients presenting with NIHSS < 8 and NIHSS ≥ 8 as evidenced by non-significantly different aOR. Interventional safety and efficacy metrics were similar between patients with NIHSS < 8 and NIHSS ≥ 8.

CONCLUSIONS

Achieving successful reperfusion is beneficial in patients with persisting LVO presenting with NIHSS < 8 and reduces the risk of non-hemorrhagic neurological worsening.