Previous guidelines during the COVID-19 pandemic stressed the need for maintenance of services providing emergent mechanical thrombectomy (MT) in patients with cerebral large-vessel occlusion.¹ The time-critical nature of MT precludes awaiting the results of any COVID-19 reverse transcriptase–polymerase chain reaction (RT-PCR) swab test, which initially could take up to 24 hours and has a false-negative rate. Furthermore, patients with SARS-CoV-2 infection may be asymptomatic and patients with acute ischemic stroke may not be able to provide a reliable clinical history or screening information due to underlying dysphasia or impaired consciousness. In combination, establishing COVID-related risks in this population is challenging.

This study described the feasibility and outcome of implementing a pragmatic, modified, imaging triaging algorithm by the inclusion of a chest CT in the work-up of hyperacute stroke referrals for MT across a network of primary stroke centers.

The high sensitivity and negative predictive values reported were encouraging in our patient cohort and lent some support to findings from previous studies that reported the potential benefit of chest CT in identifying features of COVID-19.² However, its low-to-moderate specificity and positive predictive value preclude its use as a stand-alone screening tool for COVID-19. The small addition of the radiation dose and scanning time incurred may be outweighed by the potential benefits of the outreaching effects on the patient management and safety of the involved health care staff.

Following retrospective review of the thoracic imaging, multiple incidental findings were identified, including potential cardiac causes for large-vessel occlusion, and clinically relevant thoracic findings, which highlight the range of comorbidities present in a cohort of older patients with cardiovascular disease. Knowledge of these risk factors may be a factor that alters post-MT care or secondary stroke prevention.

As further “waves” of the pandemic continue to affect various regions, chest CT may be implemented as a pragmatic, rapid additional tool for COVID-19 risk stratification among patients referred for MT. Its inclusion in a standardized regional stroke imaging protocol has enabled efficient use of hospital resources, particularly in assisting efficient use of personal protective equipment (PPE), anesthetic technique, and direction along the appropriate periprocedural patient care pathway, especially at a time when shortage of critical care or isolation beds can be a challenge, while incurring minimal compromise or delay to the overall patient treatment schedule.

This study was undertaken at the Nottingham University Hospitals NHS Trust (interventional neuroradiology) and has previously been presented at the United Kingdom Neurointerventional Group (UKNG) Scientific Meeting (July 2020).

References

1. Aggour M, White P, Kulcsar Z, et al. European Society of Minimally Invasive Neurological Therapy (ESMINT) recommendations for optimal interventional neurovascular management in the COVID-19 era. J Neurointerv Surg 2020;12:542–44
2. Fang Y, Zhang H, Xie J, et al. Sensitivity of chest CT for COVID-19: comparison to RT-PCR. Radiology 2020;296:E115–17

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