Altered pulmonary blood volume distribution as a biomarker for predicting outcomes in COVID-19 disease

Rationale: Evidence suggests that vascular inflammation and thrombosis may be important drivers of poor clinical outcomes in patients with COVID-19. We hypothesized that a significant decrease in the percentage of blood vessels with a cross-sectional area between 1.25-5 mm2 (BV5%) on chest computed tomography (CT) in COVID-19 patients is predictive of adverse clinical outcomes. Methods: Retrospective study of patients seeking acute medical care within a large integrated healthcare network from 3/1/2020-6/30/2020. Patients presenting to the emergency department, undergoing a chest CT within 24 hours of presentation, and COVID-19 testing were eligible for participation. After identification of the COVID-19-positive cohort, a randomly selected group of COVID-19-negative patients were chosen in order to achieve a target study ratio of 60% COVID-19 positive and 40% COVID-19 negative cases for analysis. Results: Patients with COVID-19 had significantly lower BV5% compared to COVID-19 negative patients (25.3% +/- 7.4 vs 30.1 % +/- 9.6;p<0.01). There was no significant difference in BV5% obtained from contrast enhanced CT versus non-contrast CT (p=0.23). Average processing time for BV5% was 9 minutes and 22 seconds (+/- 6 minutes and 3 seconds), with processing time dependent on scan quality. No CT scans were unable to be analyzed. BV5% was predictive of outcomes in COVID-19 patients in a multivariate model, with a BV5% threshold below 25% associated with an odds ratio (OR) 5.58 for death, OR 3.20 for intubation, and OR 2.54 for the composite of death or intubation. A model using age and BV5% had an area under the receiver operating characteristic curve 0.85 to predict the composite of intubation or death in COVID-19 patients. Conclusion: This data suggests BV5% as a biomarker for predicting adverse outcomes in patients with COVID-19 seeking acute medical care.