title: A prospective study of C-reactive protein as a state marker in Cardiac Syndrome X.
abstract: Cardiac Syndrome X (CSX), the presence of angina pectoris despite normal epicardial coronary arteries seen on invasive angiography, is known to be associated with an elevation of several inflammatory biomarkers, suggesting a possible role for inflammation in its pathogenesis. We sought to establish if C-reactive protein (CRP) levels varied with disease severity and so whether it is a state or trait marker. We studied 16 CSX patients with typical angina pectoris, normal coronary arteries and an electrically positive exercise stress test (EST) and 13 age- and sex-matched healthy controls (HC). CSX patients were followed up at a subsequent visit with repeated exercise stress testing and CRP measurement. We found that CRP levels were significantly higher in the CSX group compared to the HC (1.5 [0.8-4.5] v 0.8 [0.4-1.4] mg/L, p=0.02). This elevation in CRP persisted throughout the study length. CRP correlated with time to symptoms on EST at enrolment and at the second visit (r=-0.690, df=10, p=0.013 and r=-0.899, df=4, p=0.015, respectively). At the follow-up visit, 50% of CSX patients developed electrically and symptomatically negative ESTs. The mean CRP of this group was significantly lower than that of the CSX patients with ongoing symptoms and positive ESTs (1.2±0.2 v 2.8±0.6mg/L, p=0.018) and did not differ significantly from that of healthy controls. CRP levels also dropped in patients whose symptoms improved while they increased in patients who became more symptomatic (p=0.027). We conclude that the results of this small study support the concept of CSX being an inflammatory-mediated condition with CRP levels prospectively varying with functional measures of disease severity. This indicates that CRP is a state marker in CSX.
authors: Department of Cardiology, Cork University Hospital, Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
authors: James
authors: J
authors: Dollard
authors: Department of Cardiology, Cork University Hospital, Cork, Ireland.
authors: Peter
authors: P
authors: Kearney
authors: Department of Psychiatry, University College Cork, Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
authors: Gerard
authors: G
authors: Clarke
authors: Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
authors: Gerard
authors: G
authors: Moloney
authors: Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
authors: John F
authors: JF
authors: Cryan
authors: Department of Psychiatry, University College Cork, Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland. Electronic address: t.dinan@ucc.ie.
authors: Timothy G
authors: TG
authors: Dinan
mesh_terms: D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood; D008297:Male; D017566:Microvascular Angina / Q000097:blood* / Q000175:diagnosis*; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein
keywords: Angina pectoris; C-reactive protein; Inflammation; Microvascular angina; Normal coronary arteries; Stress