Global Impact of the COVID 19 Pandemic on Stroke Care, Cerebral Venous Thrombosis, and Subarachnoid Hemorrhage

A 1-year analysis of global selected stroke metric data will be conducted comparing the results during the Covid-19 pandemic to the pre-pandemic period. In most countries, this will correspond to March 1, 2020 to February 28, 2021. In some countries, the pandemic period would be adjusted for onset of case surge (i.e. China pandemic start date would begin earlier, i.e. January 2020). The specific metrics that will be analyzed include:

1. ischemic stroke or transient ischemic attacks (TIA) hospitalizations
2. intracranial hemorrhage hospitalizations
3. cerebral venous thrombosis (CVT) hospitalizations (with or without thrombocytopenia)
4. CVT in-hospital mortality

4) aneurysmal subarachnoid hemorrhage hospitalizations 5) mechanical thrombectomy 6) intravenous thrombolysis 7) ruptured aneurysm endovascular coiling 8) ruptured aneurysm clipping. 9) aneurysmal subarachnoid hemorrhage admissions 10) SAH in-hospital mortality 11) SAH presentation by Hunt Hess Grade

This is a retrospective, observational, cross-sectional, international study, across 6 continents, and estimated 100 stroke centers. The stroke metric diagnoses will be identified by their International Classification of Diseases version 10 (ICD-10) codes and/or classifications in stroke databases at participating centers. Aggregate monthly volume will be obtained from January 1, 2019 to May 31, 2021. For CVT related to COVID vaccine events, the study period extends until July 30, 2021

The primary hypotheses to be tested are:

* The overall 1-year volumes of the stroke metrics will be decreased compared to the prior year.
* With each subsequent COVID wave, there will be a decline in relation to the prior year volumes, as was seen with the first COVID-19 wave of the pandemic.
* A recovery or increase in stroke volume will occur during the vaccine roll-out phase on same metrics, compared to the immediately preceding period and/or compared to the same period one year prior.
* There will be a decline in mild clinical severity in the presentation of patients with subarachnoid hemorrhage as measured by the Hunt Hess Grade scale, parallel to the decline in mild severity of stroke admissions seen with the first wave of the pandemic. \[Mild severity of presentation is defined as Hunt Hess Grade 0-2, moderate to severe is defined as Hunt Hess Grade 3-5.\]
* There will be an increase of CVT diagnosis during the COVID-19 pandemic year, related either to heightened awareness of COVID-19 and thrombotic events, or related to reported associations of CVT and COVID-19.

The ICD codes utilized for the diagnosis are as follows:

Ischemic Stroke, ICD-10 Codes

I63.0 Cerebral Infarction

I63.1 Cerebral infarction due to embolism of precerebral arteries

I63.2 Cerebral infarction due to unspecified occlusion or stenosis of precerebral arteries

I63.3 Cerebral infarction due to thrombosis of cerebral arteries

I63.4 Cerebral infarction due to embolism of cerebral arteries

I63.5 Cerebral infarction due to unspecified occlusion or stenosis of cerebral arteries

I63.8 Other cerebral infarction

I63.9 Cerebral infarction, unspecified

Intracranial Hemorrhage, ICD-10 Codes

I61 Nontraumatic intracerebral hemorrhage

I61.0 Nontraumatic intracerebral hemorrhage in hemisphere, subcortical

I61.1 Nontraumatic intracerebral hemorrhage in hemisphere, cortical

I61.2 Nontraumatic intracerebral hemorrhage in hemisphere, unspecified

I61.3 Nontraumatic intracerebral hemorrhage in brain stem

I61.4 Nontraumatic intracerebral hemorrhage in cerebellum

I61.5 Nontraumatic intracerebral hemorrhage, intraventricular

I61.6 Nontraumatic intracerebral hemorrhage, multiple localized

I61.8 Other nontraumatic intracerebral hemorrhage

I61.9 Nontraumatic intracerebral hemorrhage, unspecified

Cerebral Venous thrombosis, Codes

G08 Intracranial Phlebitis and Thrombophlebitis I63.6 Cerebral infarction due to cerebral venous thrombosis, nonpyrogenic I67.6 Nonpyrogenic Thrombosis of Intracranial Venous System O22.5 Cerebral venous thrombosis in pregnancy

Subarachnoid Hemorrhage, Codes

I60.0 Nontraumatic subarachnoid hemorrhage from carotid siphon and bifurcation

I60.1 Nontraumatic subarachnoid hemorrhage from middle cerebral artery

I60.2 Nontraumatic subarachnoid hemorrhage from anterior communicating artery

I60.3 Nontraumatic subarachnoid hemorrhage from posterior communicating artery

I60.4 Nontraumatic subarachnoid hemorrhage from basilar artery

I60.5 Nontraumatic subarachnoid hemorrhage from vertebral artery

I60.6 Nontraumatic subarachnoid hemorrhage from other intracranial arteries

I60.7 Nontraumatic subarachnoid hemorrhage from unspecified intracranial artery

I60.8 Other nontraumatic subarachnoid hemorrhage

I60.9 Nontraumatic subarachnoid hemorrhage, unspecified

COVID19

UO7.1

Eligibility Criteria:
Inclusion Criteria:

* Received stroke related care during the study period in one of the stroke centers across 6 continents

Exclusion Criteria:

* None