Higher Initial Platelet Procoagulant Potential is Associated with Lower Cognitive Scores at 14 Months after COVID-19
Claire Delpirou Nouh1, Calin Prodan1, Chao Xu2, Andrea Vincent5, Eleanor Mathews1, Leslie Guthery1, Jason Sharps1, Jim Scott3, George Dale4, Angelia Kirkpatrick4
1Neurology, 2Biostatistics and Epidemiology, 3Psychiatry, 4Medicine, University of Oklahoma Health Sciences Center, 5Cognitive Research Center, University of Oklahoma
Objective:

To examine whether coated-platelet levels measured at the time of acute SARS-CoV-2 infection predict cognitive impairment after recovery from COVID-19.

Background:
Coated-platelets are a subset of highly procoagulant platelets observed upon dual agonist stimulation with collagen and thrombin. Coated-platelet levels are increased in ischemic stroke compared to controls, and higher levels are associated with stroke recurrence. Previously, we have shown that higher coated-platelet levels at baseline are predictive of death at 90 days in COVID-19. Cognitive symptoms are frequently reported after recovery from SARS-CoV-2 infection. 
Design/Methods:

After consent, patients with acute SARS-CoV-2 infection were enrolled. Coated-platelet levels were assayed at the time of admission and then weekly during the hospitalization. Symptoms of post-COVID-19 syndrome were evaluated using the CDC questionnaire. Cognitive screening was completed by telephone using the MoCA test for the blind, version 8.1. Regression analysis was used to evaluate the effect of clinical variables, demographics and coated-platelet levels on MoCA score.

Results:
We recruited 38 patients admitted with COVID-19. The 32 surviving patients were interviewed by telephone for long COVID symptoms at 14.8±2.4 months after infection. Twenty subjects (67%) reported having ≥1 long-COVID symptoms, most often brain fog and fatigue (39.4%). Among the 29 subjects (average age 65.5 years, range 33-88) who agreed to complete MoCA testing, mean MoCA score was 16.6 (range 10-21), with 17 (58.6%) screening positive for cognitive impairment. Coated-platelet levels drawn at enrollment during hospitalization for COVID-19 were inversely associated with MoCA scores after adjusting for age and time from symptom onset (adjusted R2=0.2, p=0.037). A 10% absolute increase in baseline coated-platelet levels corresponded to a 1.3-point decrease in MoCA score (p=0.009).
Conclusions:
These findings suggest that platelet procoagulant potential is linked to long-term lower cognitive performance after SARS-CoV-2 infection. Future work is needed to investigate coated-platelets and post-COVID cognitive decline.
10.1212/WNL.0000000000203122