Clinical Outcomes and Identification of Patients With Persistent Penumbral Profiles Beyond 24 Hours From Last Known Well: Analysis From DEFUSE 3

Endovascular treatment for acute ischemic stroke beyond the 24-h time window: Selection by target mismatch profile

INTRODUCTION

Endovascular treatment for acute ischemic stroke patients with large vessel occlusion (LVO) has been established as a promising clinical intervention within a late time window of 6-24 h after symptom onset. Patients with slow progression, however, may still benefit from endovascular treatment beyond the 24-h time window (very late window).

AIM

The aim of this study is to report insight into the potential clinical benefits of endovascular treatment for acute ischemic stroke beyond 24 h from symptom onset.

METHODS

A retrospective analysis was performed on consecutive patients undergoing endovascular treatment for acute anterior circulation LVO ischemic stroke beyond 24 h. Participants were recruited between July 2019 and November 2020. Patients were selected based on the DAWN/DEFUSE 3 criteria (Perfusion-RAPID, iSchemaView) and patients receiving treatment beyond 24 h were compared to a group of patients receiving endovascular treatment between 6 and 24 h after symptom onset. The primary outcome was the proportion of patients with functional independence at 90 days (modified Rankin Scale score of 0-2). The secondary outcomes were shift modified Rankin Scale (mRS) analysis and successful reperfusion was defined by thrombolysis in cerebral infarction (TICI) 2b-3 on the final procedure. Safety outcomes were symptomatic intracranial hemorrhage and death at the 90-day follow-up. Propensity score (PS)-matched analyses were employed to rectify the imbalanced baseline characteristics between the two groups.

RESULTS

A total of 166 patients were recruited with a median age of 63.0 (56.0-69.0) and 28.9% of all patients were females. Patients in the beyond 24-h group had a longer onset-to-groin time (median = 27.2 vs 14.3 h, p < 0.001) than those in the 6- to 24-h group. There were no statistically significant differences between the two groups in National Institutes of Health Stroke Scale (NIHSS) (median = 12.0 vs 15.0, p = 0.37), perfusion imaging characteristics (core: median = 11.0 vs 9.0 mL, p = 0.86; mismatch volume: median = 106.0 vs 96.0, p = 0.44; mismatch ratio = 6.46 vs 7.24, p = 0.91), and perfusion-to-groin time (median = 72.5 vs 76.0 min, p = 0.77). No significant differences were noted among patients between the two groups in the primary endpoint functional independence analysis (50.0% vs 46.6%, p = 0.77) and in the safety endpoint analysis: mortality (15.0% vs 11.0%, p = 0.71) or symptomatic hemorrhage (0% vs 3.42%, p > 0.999). In PS-matched analyses, there were no significant differences among patients between the two groups in functional independence (50.0% vs 54.8%, p = 0.74), mortality (16.7% vs 9.68%, p = 0.50), or symptomatic hemorrhage (0% vs 6.45%, p = 0.53).

CONCLUSION

Endovascular treatment can be performed safely and effectively in LVO patients beyond 24 h from symptom onset when selected by target mismatch profile. The clinical outcome of these patients was comparable to those treated in the 6- to 24-h window. Larger studies are needed to confirm these findings.

Association between blood pressure and endovascular treatment outcomes differs by baseline perfusion and reperfusion status

We hypothesized that the association between BP and endovascular treatment (EVT) outcomes would differ by baseline perfusion and recanalization status. We identified 388 ICA or M1 occlusion patients who underwent EVT ≤ 24 h from onset with successful recanalization (TICI ≥ 2b). BP was measured at 5-min intervals from arrival and during the procedure. Systolic BPs (SBP) were summarized as dropmax (the maximal decrease over two consecutive measurements), incmax (the maximal increase), mean, coefficient of variation (cv), and standard deviation. Adequate baseline perfusion was defined as hypoperfusion intensity ratio (HIR) ≤ 0.5; infarct proportion as the volume ratio of final infarcts within the Tmax > 6 s region. In the adequate perfusion group, infarct proportion was closely associated with SBPdropmax (β ± SE (P-value); 1.22 ± 0.48, (< 0.01)), SBPincmax (1.12 ± 0.33, (< 0.01)), SBPcv (0.61 ± 0.15 (< 0.01)), SBPsd (0.66 ± 0.08 (< 0.01)), and SBPmean (0.71 ± 0.37 (0.053) before recanalization. The associations remained significant only in SBPdropmax, SBPincmax, and SBPmean after recanalization. SBPincmax, SBPcv and SBPsd showed significant associations with modified Rankin Scale score at 3 months in the pre-recanalization period. In the poor perfusion group, none of the SBP indices was associated with any stroke outcomes regardless of recanalization status. BP may show differential associations with stroke outcomes by the recanalization and baseline perfusion status.

Mechanical thrombectomy for acute large vessel occlusion stroke beyond 24 h

BACKGROUND

Multiple trials have shown that mechanical thrombectomy (MT) is superior to medical therapy. However, no robust evidence is available regarding MT beyond 24 h. In this study, we aimed to determine the safety and efficacy of endovascular stroke therapy in this late window.

METHODS

We conducted a retrospective study of prospectively collected data of patients who met extended window trial criteria, but underwent MT beyond 24 h. Safety and efficacy outcomes included symptomatic intracerebral hemorrhage (sICH), procedural complications, number of passes, successful recanalization (mTICI 2b - 3), delta (Δ) NIHSS (baseline-discharge), and favorable outcomes (mRS 0-2 at 90 days).

RESULTS

A total of 39 patients were included with a median age of 69 years (IQR 61.5, 73.5); 54% were females. Hypertension was present in 76% of patients; 23% were smokers. Half of the patients had M1 occlusion (48.7%). Median preprocedural NIHSS was 11 (IQR 7.0, 19.5). Successful revascularization was achieved in 87%; median number of passes was 2 (IQR 1.0, 3.0). Median ΔNIHSS was 3.0 (IQR -1.5, 8.0). Favorable outcome was achieved in 49% (95% CI: 34%-64%), and 95% were free of complications. A total of 3 patients (7.7%) had sICH. In an exploratory analysis, posterior circulation occlusion was associated with higher mRS at 90 days (OR: 14.7, p = 0.016). Favorable discharge facility was associated with lower mRS at 90 days (OR: 0.11, p = 0.004).

CONCLUSIONS

Our study showed comparable clinical outcomes of MT beyond 24 h compared to MT trials within 24 h in patients with favorable imaging profile, especially in anterior circulation occlusions.

Collateral circulation predicts 3-month functional outcomes of subacute ischemic stroke patients: A study combining arterial spin labeling and MR angiography

OBJECTIVE

Collateral circulation could help preserve the blood supply and protect penumbra in ischemic stroke (IS), critical for late-window therapeutic decisions and clinical outcomes. In this study, we aimed to investigate the prognostic value of two collateral indexes measured by arterial spin labeling (ASL) and MR angiography (MRA) in subacute IS patients.

MATERIALS AND METHODS

Fifty-five subacute IS patients with large artery atherosclerosis were retrospectively collected. Arterial transit artifact (ATA) on ASL and good circulation (GC) on MRA were ranked as markers of leptomeningeal collaterals and fast collaterals, respectively. Volume and relative cerebral blood flow (rCBF) of infarct and hypoperfusion area were calculated. Stroke severity was determined by baseline- and discharge- National Institute of Hospital Stroke Scale (NIHSS). Functional independence (FI) was defined as 3-month modified Ranking Scale ≤2. Univariate analyses and multivariable logistic regression analyses were conducted to identify the independent predictors of FI.

RESULTS

Thirty-eight patients (69.1 %) presented ATA and 29 (52.7 %) patients presented GC. Univariate analyses showed that baseline-NIHSS, discharge-NIHSS, rCBF of infarct, presence of ATA and GC were associated with FI (P < 0.05). After multivariable adjustment, ATA (adjusted Odds Ratio [OR]: 13.785, 95 % CI: 2.608-72.870, P = 0.002) and GC (adjusted OR: 8.317, 95 % CI: 1.629-42.454, P = 0.011) remained independent predictors of FI. Besides, patients with both ATA and GC had the highest frequencies of FI while patients with neither of them showed the lowest (94.7 % vs 14.3 %, P < 0.001), indicating a positive synergistic effect between ATA and GC.

CONCLUSION

The combination of ASL and MRA simultaneously reflects leptomeningeal collaterals and fast collaterals, providing a useful method to predict functional outcomes of subacute IS patients.

Association of Endovascular Thrombectomy vs Medical Management With Functional and Safety Outcomes in Patients Treated Beyond 24 Hours of Last Known Well: The SELECT Late Study

Importance

The role of endovascular thrombectomy is uncertain for patients presenting beyond 24 hours of the time they were last known well.

Objective

To evaluate functional and safety outcomes for endovascular thrombectomy (EVT) vs medical management in patients with large-vessel occlusion beyond 24 hours of last known well.

Design, Setting, and Participants

This retrospective observational cohort study enrolled patients between July 2012 and December 2021 at 17 centers across the United States, Spain, Australia, and New Zealand. Eligible patients had occlusions in the internal carotid artery or middle cerebral artery (M1 or M2 segment) and were treated with EVT or medical management beyond 24 hours of last known well.

Interventions

Endovascular thrombectomy or medical management (control).

Main Outcomes and Measures

Primary outcome was functional independence (modified Rankin Scale score 0-2). Mortality and symptomatic intracranial hemorrhage (sICH) were safety outcomes. Propensity score (PS)-weighted multivariable logistic regression analyses were adjusted for prespecified clinical characteristics, perfusion parameters, and/or Alberta Stroke Program Early CT Score (ASPECTS) and were repeated in subsequent 1:1 PS-matched cohorts.

Results

Of 301 patients (median [IQR] age, 69 years [59-81]; 149 female), 185 patients (61%) received EVT and 116 (39%) received medical management. In adjusted analyses, EVT was associated with better functional independence (38% vs control, 10%; inverse probability treatment weighting adjusted odds ratio [IPTW aOR], 4.56; 95% CI, 2.28-9.09; P < .001) despite increased odds of sICH (10.1% for EVT vs 1.7% for control; IPTW aOR, 10.65; 95% CI, 2.19-51.69; P = .003). This association persisted after PS-based matching on (1) clinical characteristics and ASPECTS (EVT, 35%, vs control, 19%; aOR, 3.14; 95% CI, 1.02-9.72; P = .047); (2) clinical characteristics and perfusion parameters (EVT, 35%, vs control, 17%; aOR, 4.17; 95% CI, 1.15-15.17; P = .03); and (3) clinical characteristics, ASPECTS, and perfusion parameters (EVT, 45%, vs control, 21%; aOR, 4.39; 95% CI, 1.04-18.53; P = .04). Patients receiving EVT had lower odds of mortality (26%) compared with those in the control group (41%; IPTW aOR, 0.49; 95% CI, 0.27-0.89; P = .02).

Conclusions and Relevance

In this study of treatment beyond 24 hours of last known well, EVT was associated with higher odds of functional independence compared with medical management, with consistent results obtained in PS-matched subpopulations and patients with presence of mismatch, despite increased odds of sICH. Our findings support EVT feasibility in selected patients beyond 24 hours. Prospective studies are warranted for confirmation.

Leaving the day behind: endovascular therapy beyond 24 h in acute stroke of the anterior and posterior circulation

Background:

There is little evidence of endovascular therapy (EVT) being performed in acute ischemic stroke beyond 24 h, and that evidence is limited to anterior circulation stroke.

Objective:

To extend evidence of efficacy and safety of EVT after more than 24 h in both anterior and posterior circulation stroke.

Methods:

Local, prospectively collected registries were screened for patients with acute ischemic stroke and large-vessel occlusion who had received either EVT > 24 h after last-seen-well but <24 h after symptom recognition (EVT_>24LSW) or EVT > 24 h since first (definitive) symptom recognition (EVT_>24DEF). Patients treated <24 h served as a group for comparison. Favorable outcome was defined as modified Rankin scale (mRS) 0–2 or return to prestroke mRS at 3 months.

Results:

Between January 2014 and August 2021, N = 2347 were treated with EVT at our comprehensive stroke center, of whom n = 43 met the inclusion criteria (EVT_>24LSW, n = 16, EVT_>24DEF, n = 27). EVT_>24LSW patients were treated at a median of 28.7 h [interquartile range (IQR) = 27.3–32.8] after last-seen-well and 7.3 h (IQR = 2.8–14.3) after symptom recognition; EVT_>24DEF patients were treated 52.5 h (IQR = 26.5–94.2) after first symptoms. Favorable outcome was achieved by 23.3% (10/43) in the EVT > 24 compared with 39.4% (886/2250) in the EVT < 24 group (p = 0.04). Bleeding rates were similar across groups. Mortality was also similar [EVT > 24, 27.9% (12/43) versus EVT < 24, 25.7% (584/2264), p = 0.727; posterior circulation, EVT > 24, 41.7% (5/12) versus EVT < 24, 36.5% (92/252) p = 0.764].

Conclusion:

In selected patients, EVT seems effective and safe beyond 24 h for both anterior and posterior circulation stroke.

Ischemic Penumbra: A Personal View

The concept of the ischemic penumbra was defined over 40 years ago by Lindsay Symon and his group and is now an established principle of all acute ischemic stroke therapies. These reperfusion treatments rescue threatened, critically hypoperfused brain tissue and have been proven to improve clinical outcomes. We have been fortunate to have observed and played a small part in the penumbral story from its beginnings in the 1970s to its pivotal position today. Over this period, we have witnessed penumbral imaging evolve from positron emission tomography through to magnetic resonance imaging and now predominantly computed tomography perfusion, with the advent of automated imaging facilitating case selection for reperfusion therapies. We and others have conducted clinical trials using penumbral imaging to extend the time window for intravenous thrombolysis and select patients for thrombectomy. Together with the concept of fast- and slow-growing ischemic infarct patterns, this embeds the penumbral principle in everyday clinical management. The opportunity now exists to make penumbral imaging even more portable, affordable, and more widely available using mobile platforms, novel imaging techniques, digital linkage, and artificial intelligence.

The core/penumbra model: implications for acute stroke treatment and patient selection in 2021

Despite major advances in prevention, ischaemic stroke remains one of the leading causes of death and disability worldwide. After centuries of nihilism and decades of failed neuroprotection trials, the discovery, initially in non-human primates and subsequently in man, that ischaemic brain tissue termed the ischaemic penumbra can be salvaged from infarction up to and perhaps beyond 24 h after stroke onset has underpinned the development of highly efficient reperfusion therapies, namely intravenous thrombolysis and endovascular thrombectomy, which have revolutionized the management of the acute stroke patient. Animal experiments have documented that how long the penumbra can survive depends not only on time elapsed since arterial occlusion ('time is brain'), but also on how severely perfusion is reduced. Novel imaging techniques allowing the penumbra and the already irreversibly damaged core in the individual subject to be mapped have documented that the time course of core growth at the expense of the penumbra widely differs from patient to patient, and hence that individual physiology should be considered in addition to time since stroke onset for decision-making. This concept has been implemented to optimize patient selection in pivotal trials of reperfusion therapies beyond 3 h after stroke onset and is now routinely applied in clinical practice, using computed tomography or magnetic resonance imaging. The notion that, in order to be both efficient and harmless, treatment should be tailored to each patient's physiological characteristics represents a radical move towards precision medicine.