Platelet activation and COPD-related clinical and imaging characteristics: The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study

Abstract

Introduction: The pulmonary vasculature has been implicated in chronic obstructive pulmonary disease (COPD). Whether platelet activation is associated with COPD-related characteristics is unknown.

Methods: The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study enrolled participants with 10+ pack-years with and without COPD from 2 cohort studies. Platelet activation was measured in platelet-free plasma as von Willebrand factor (vWF), beta-thromboglobulin (BTG) and platelet factor 4 (PF4). Phenotyping included spirometry, percent emphysema_-950HU, air trapping on computed tomography (CT), low-ventilated lung volume on ³He-magnetic resonance imaging (MRI) and contrast-enhanced MRI pulmonary perfusion on and off oxygen. Linear and logistic regression adjusted for demographics, anthropometry, platelet count, aspirin use, COPD status and cohort; the final model adjusted for smoking, pack-years, oxygen saturation and hypertension.

Results: The 116 with vWF were a mean age of 73.5 ± 7.3 years old, 60 % male, 58 % Non-Hispanic White, 28 % Black, 14 % Hispanic/Latino, 23 % smoked currently and 55 % had COPD. vWF was associated with lower FEV₁/FVC (-2.0 %/SD vWF, 95 %CI: -3.5, -0.6), and greater percent low-ventilated lung volume on ³He-MRI (6.5 %/SD vWF, 95 %CI: 1.5, 11.5), CT air trapping (3.2 %/SD vWF, 95 %CI: 1.4, 5.1) and heterogeneity (CV) of pulmonary microvascular blood flow (PMBF) and pulmonary microvascular blood volume (PMBV) on oxygen. Higher BTG and PF4 were associated with greater PMBF and PMBV. There was increased odds of COPD with higher PF4 (final model only: OR 1.8/SD PF4, 95 %CI: 1.01, 3.20).

Conclusions: Platelet activation was associated with measures of small airways disease and pulmonary microvascular perfusion in this sample of smokers with and without COPD.

Keywords: COPD; Imaging in COPD; Platelet activation; Small airways disease.