Increased Platelet Procoagulant Potential is Associated with Silent Brain Infarcts in Ischemic Stroke Patients
Philion Gatchoff1, Angelia Kirkpatrick1, Chao Xu1, Andrea Vincent2, Bappaditya Ray3, Sergio Ramirez-Salazar4, Meheroz Rabadi5, George Dale1, Calin Prodan1
1University of Oklahoma Health Sciences Center, 2University of Oklahoma, 3UT Southwestern Medical Center, 4Dartmouth Hitchcock Medical Center, 5Dept of VA Medical Center #127
Objective:
To evaluate if platelet procoagulant potential is associated with the presence of silent brain infarcts (SBIs) in ischemic stroke.
Background:
Coated-platelets, a subset of highly procoagulant platelets observed upon dual-agonist stimulation with collagen and thrombin, represent ~32% of all platelets in healthy controls. Elevated coated-platelet levels are associated with increased risk for recurrence in patients with ischemic stroke, whereas lower levels of coated-platelets are present with early hemorrhagic transformation or hemorrhagic complications after stroke. SBIs are common in elderly patients with stroke.
Design/Methods:
Coated-platelet levels, reported as percent of cells converted to coated-platelets, were assayed in consecutive ischemic stroke patients <96 hours from symptoms onset. Subjects with intracerebral hemorrhage, myocardial infarction, dementia or recent blood transfusions were excluded. Demographics, medications, comorbidities, and laboratory values were recorded for each participant. The presence of SBIs on 1.5 T MRI was recorded by two independent reviewers. Logistic regression was used to identify factors associated with SBI presence. Correlations between number of SBIs and coated-platelet levels, demographics, and clinical and laboratory data were calculated using the Spearman correlation coefficient.
Results:
We analyzed 249 stroke patients, with a mean age of 65.7 years (range 42-91) and mean coated-platelet levels of 39% (SD 14.4%). Logistic regression identified coated-platelet levels, mean platelet volume, hypertension, obesity, hyperlipidemia and prior stroke as independently associated with SBI presence (p values <0.04). After adjusting for all variables in the model, a 10% absolute increase in coated-platelet levels was associated with 80% higher odds of SBI (95 CI:44%-124%). The numbers of SBIs correlated positively with coated-platelet levels, after adjusting for hypertension, hyperlipidemia, and prior stroke (adjusted r=0.4 , p<0.001).
Conclusions:
Increased platelet procoagulant potential is associated with the presence and the number of SBIs in stroke patients. These results support a role for procoagulant platelets in ischemic stroke, with implications for recurrence and vascular cognitive impairment.
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