Measurement of biochemical markers
Peripheral venous blood samples were collected after 15 minutes of rest into tubes containing ethylenediaminetetraacetic acid (EDTA). Troponin-I levels were measured by chemiluminescent immunoassay using an Immulite 2500 device (Siemens Medical Solutions, Erlangen, Germany). MCP-1 and SP-A levels were measured by enzyme-linked immunosorbent assay (Elabscience human ELISA kit, UK).