Clinical Outcomes from Thrombectomy and Time Metrics in Large Vessel Occlusion Acute Ischemic Stroke, Before and After Implementation of Preprocedural and Intraprocedural COVID-19 Infection Control Protocol

COVID-19 Research Area(s): Healthcare Delivery & Policy

Summary:

Every 10 minutes, one person in Canada suffers a stroke, or brain attack. Of these, approximately 85% are related to a blood clot traveling to the brain.

Once the clot lodges in the brain, a very short window of time exists before the area of brain tissue next to the clot starves of oxygen and dies.

About 10-20% of such patients may benefit from an image guided minimally invasive procedure in which the clot is removed, called a mechanical thrombectomy (MT). This MT procedure is successful in removing clot over 90% of the time, and leads to significant improvement in symptoms in 30-50% of thrombectomy patients. Success of the MT procedure is dependent on very fast movement of patients from the ED, to CT scanner, to procedure room, to clot removal.

The COVID-19 pandemic has required implementation of infection control policies and procedures to minimize risk of COVID-19 transmission to other patients and medical staff. Such measures can often delay the removal of clot. The effect of these infection control measures on the clinical outcomes and time metrics in the setting of these procedures on stroke patients are unknown. This study aims to evaluate the effect of the COVID19 infection control protocols on the outcomes of stroke patients.

Clinical Description:

Every 10 minutes, one person in Canada suffers a stroke. Of these, approximately 85% are ischemic in etiology. Approximately, 10-20% of patients with an acute ischemic stroke (AIS) related to a large vessel occlusion (LVO) may be suitable candidates for endovascular thrombectomy (EVT).

Rapid reperfusion from EVT improves functional outcomes and reduces mortality from LVO AIS. Every 30 minute delay in reperfusion causes a 10% decrease in the probability of a good clinical outcome (mRS 0-2). Tracking time metrics in EVT for LVO AIS is important for ongoing quality improvement efforts. Nearly 200 acute thrombectomies are performed at Vancouver General Hospital per year, the largest volume in BC, for patients from across the province.

The COVID-19 pandemic has required the implementation of infection control policies and procedures from the ED to the angiography suite, to minimize risk of COVID-19 transmission to other patients and medical staff, especially via aerosol generating medical procedures, such as induction of general anesthesia (GA). A large percentage of EVT procedures require GA, or may be converted intraprocedurally from conscious sedation or MAC to GA. The effects of such infection control measures on the clinical outcomes and time metrics in the setting of LVO AIS are unknown.

The purpose of this study is to retrospectively evaluate the clinical outcomes of LVO AIS patients treated with EVT before and after the implementation of an institutional preprocedural and intraprocedural COVID-19 infection control protocols. We also intend to quantify the time delays in thrombectomy treatment and reperfusion, related to implementation of these COVID 19 protocols.

Data from this study can inform clinical practice as well as policy, since a large percentage of patients receiving thrombectomy are transferred from hospitals across B.C. The results will be generalizable to other EVT-stroke centres in Canada and worldwide.