Ischemic core thresholds change with time to reperfusion: A case control study

Bivard, Andrew; Kleinig, Timothy; Miteff, Ferdinand; Butcher, Ken; Lin, Longting; Levi, Christopher; Parsons, Mark

doi:10.1002/ana.25109

Cited by 96 publications

(113 citation statements)

References 23 publications

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“…CBF) associated with infarction should progressively increase over time as infarcts grow into penumbra. 2,4 Unlike previous work that showed a relationship between optimal perfusion thresholds and imaging-to-reperfusion time, this analysis, more intuitively, shows that these thresholds are also dependent on onset-toreperfusion-time. 2 Interestingly, the association between optimal CTP thresholds and onset-to-reperfusion time was weaker when patients presented late.…”

Section: Discussioncontrasting

confidence: 61%

Confirmatory Study of Time-Dependent Computed Tomographic Perfusion Thresholds for Use in Acute Ischemic Stroke

Qiu

Kuang

Lee

et al. 2019

Stroke

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Background and Purpose— Computed tomographic perfusion (CTP) thresholds associated with follow-up brain infarction may differ by time from symptom onset to imaging and reperfusion. We confirm CTP thresholds over time to imaging and reperfusion in patients with acute ischemic stroke from the HERMES collaboration (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) data. Methods— Patients with occlusion on CT angiography were acutely imaged with CTP. Noncontrast CT and magnetic resonance-diffusion weighted imaging at 24 to 48 hours defined follow-up infarction. Reperfusion was assessed on conventional angiogram. Tmax, cerebral blood flow (CBF), and cerebral blood volume maps were derived from delay-insensitive CTP postprocessing. These parameters were analyzed using receiver operator characteristics to derive optimal thresholds based on time from stroke onset-to-CTP or to reperfusion. ANOVA and linear regression were used to test whether the derived CTP thresholds were different by time. Results— One hundred thirty-seven patients were included. Tmax thresholds of >15.7 s and >15.8 s and absolute CBF thresholds of <8.9 and <7.5 mL·min −1 ·100 g −1 for gray matter and white matter respectively were associated with infarct if reperfusion was achieved <90 minutes from CTP with stroke onset-to-CTP <180 minutes. The discriminative ability of cerebral blood volume was modest. There were no statistically significant relationships between stroke onset-to-CTP time and Tmax, CBF, and cerebral blood volume thresholds (all P >0.05). A statistically significant relationship was observed between CTP-to-reperfusion time and the optimal thresholds for Tmax ( P <0.001) and CBF ( P <0.001). Similar but more modest relationship was noted for onset-to-reperfusion time and optimal thresholds for CBF ( P ≤0.01). Conclusions— CTP thresholds based on stroke onset and imaging time and taking into account time needed for reperfusion may improve infarct prediction in patients with acute ischemic stroke.

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Section: Discussioncontrasting

confidence: 61%

Confirmatory Study of Time-Dependent Computed Tomographic Perfusion Thresholds for Use in Acute Ischemic Stroke

Qiu

Kuang

Lee

et al. 2019

Stroke

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“…Furthermore, only 56.7% of that study population were identified with ICA/M1 occlusion/stenosis, and rFTD is a crude estimation only for occlusion in ICA or proximal M1 large vessel occlusion. We used the ratio between the volume of hypoperfused "penumbral range" tissue (DT >3 seconds) and the volume of tissue within the total DT >3 seconds lesion with more severe delay (DT >6 seconds) to evaluate the collateral flow . DT is essentially a quantification of collateral flow, measuring the time it takes for contrast to arrive in ischemic tissue .…”

Section: Discussionmentioning

confidence: 99%

“…Computed tomography (CT) perfusion (CTP) imaging has been widely used to determine infarct core and penumbra in acute ischemic stroke patients. Cerebral collateral flow can be quantified using CTP imaging data by measuring the volume of tissue with delayed contrast transit instead of conventional CT angiography (CTA) collateral grading . More severe delay in contrast transit indicates poorer collateral flow.…”

mentioning

confidence: 99%

The blood pressure paradox in acute ischemic stroke

Hong

Cheng

Lin

et al. 2019

Annals of Neurology

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on behalf of the INSPIRE Study GroupObjective: To explore the association of poststroke baseline blood pressure with cerebral collateral flow and functional outcome in acute ischemic patients with large vessel occlusion/stenosis. Methods: Patients identified with large vessel occlusion/stenosis with baseline multimodal computed tomography, followup imaging, and complete clinical profiles were included. A 90-day modified Rankin Scale of 0-1 was defined as an excellent functional outcome. Cerebral collateral flow was quantified by the volume ratio of tissue within the delay time >3 seconds perfusion lesion with severely delayed contrast transit (delay time >3 seconds/delay time >6 seconds). Results: There were 306 patients included in this study. With every increase of 10 mmHg in baseline systolic blood pressure, the odds of achieving an excellent functional outcome decreased by 12% in multivariate analysis (odds ratio = 0.88, p = 0.048). Conversely, increased baseline blood pressure was associated with better collateral flow. In subgroup analysis of patients with major reperfusion, higher blood pressure was associated with decreased infarct growth and a better clinical outcome, and vice versa in patients without reperfusion. Interpretation: Higher baseline blood pressure in acute ischemic stroke patients with large vessel occlusion/stenosis was associated with better collateral flow. However, for patients without reperfusion, higher baseline blood pressure was associated with increased infarct growth, leading to an unfavorable clinical outcome. The relationship between blood pressure and outcomes is highly dependent on reperfusion, and active blood pressure-lowering treatment may be inappropriate in acute ischemic stroke patients prior to reperfusion treatment.

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“…Unsurprisingly, ASPECTS scores were lower in patients who presented at a later time from LKN, although there was no significant relationship between time‐to‐imaging and change in perfusion imaging parameters. These data emphasize the role of the noncontrast CT in identifying early and potentially irreversible cerebral infarction when perfusion imaging may show minimal or no areas of “ischemic core.” It is possible that subcritical oligemia (rCBF >30%, for example) may still result in neuronal death—especially in the extended time window—but this degree of hypoperfusion could be missed using thresholds prespecified by RAPID and other automated software platforms. Therefore, it remains critical that perfusion imaging be interpreted in conjunction with the simultaneously acquired noncontrast CT, in accordance with the clinical trials, which demonstrated efficacy using these tools.…”

Section: Discussionmentioning

confidence: 99%

Noncontrast CT versus Perfusion‐Based Core Estimation in Large Vessel Occlusion: The Blood Pressure after Endovascular Stroke Therapy Study

Siegler

Messé

Sucharew

et al. 2019

Journal of Neuroimaging

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BACKGROUND AND PURPOSE The 2018 AHA guidelines recommend perfusion imaging to select patients with acute large vessel occlusion (LVO) for thrombectomy in the extended window. However, the relationship between noncontrast CT and CT perfusion imaging has not been sufficiently characterized >6 hours after last known normal (LKN). METHODS From a multicenter prospective cohort of consecutive adults who underwent thrombectomy for anterior LVO 0–24 hours after LKN, we correlated baseline core volume (rCBF < 30%) and the Alberta Stroke Program Early CT Scale (ASPECTS) score. We compared perfusion findings between patients with an unfavorable ASPECTS (<6) against those with a favorable ASPECTS (≥6), and assessed findings over time. RESULTS Of 485 enrolled patients, 177 met inclusion criteria (median age: 69 years, interquartile range [IQR: 57‐81], 49% female, median ASPECTS 8 [IQR: 6‐9], median core 10 cc [IQR: 0‐30]). ASPECTS and core volume moderately correlated (r = −.37). A 0 cc core was observed in 54 (31%) patients, 70% of whom had ASPECTS <10. Of the 28 patients with ASPECTS <6, 3 (11%) had a 0 cc core. After adjustment for age and stroke severity, there was a lower ASPECTS for every 1 hour delay from LKN (cOR: 0.95, 95% confidence of interval [CI]: 0.91‐1.00, P = .04). There was no difference in core (P = .51) or penumbra volumes (P = .87) across patients over time. CONCLUSIONS In this multicenter prospective cohort of patients who underwent thrombectomy, one‐third of patients had normal CTP core volumes despite nearly three quarters of patients showing ischemic changes on CT. This finding emphasizes the need to carefully assess both noncontrast and perfusion imaging when considering thrombectomy eligibility.

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Ischemic core thresholds change with time to reperfusion: A case control study

Cited by 96 publications

References 23 publications

Confirmatory Study of Time-Dependent Computed Tomographic Perfusion Thresholds for Use in Acute Ischemic Stroke

Confirmatory Study of Time-Dependent Computed Tomographic Perfusion Thresholds for Use in Acute Ischemic Stroke

The blood pressure paradox in acute ischemic stroke

Noncontrast CT versus Perfusion‐Based Core Estimation in Large Vessel Occlusion: The Blood Pressure after Endovascular Stroke Therapy Study

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