Elevated Levels of C-Reactive Protein at Discharge in Patients With Unstable Angina Predict Recurrent Instability

<jats:p> <jats:italic>Background</jats:italic> —In a group of patients admitted for unstable angina, we investigated whether C-reactive protein (CRP) plasma levels remain elevated at discharge and whether persistent elevation is associated with recurrence of instability. </jats:p> <jats:p> <jats:italic>Methods and Results</jats:italic> —We measured plasma levels of CRP, serum amyloid A protein (SAA), fibrinogen, total cholesterol, and <jats:italic>Helicobacter</jats:italic> <jats:italic>pylori</jats:italic> and <jats:italic>Chlamydia</jats:italic> <jats:italic>pneumoniae</jats:italic> antibody titers in 53 patients admitted to our coronary care unit for Braunwald class IIIB unstable angina. Blood samples were taken on admission, at discharge, and after 3 months. Patients were followed for 1 year. At discharge, CRP was elevated (>3 mg/L) in 49% of patients; of these, 42% had elevated levels on admission and at 3 months. Only 15% of patients with discharge levels of CRP <3 mg/L but 69% of those with elevated CRP ( <jats:italic>P</jats:italic> <0.001) were readmitted because of recurrence of instability or new myocardial infarction. New phases of instability occurred in 13% of patients in the lower tertile of CRP (≤2.5 mg/L), in 42% of those in the intermediate tertile (2.6 to 8.6 mg/L), and in 67% of those in the upper tertile (≥8.7 mg/L, <jats:italic>P</jats:italic> <0.001). The prognostic value of SAA was similar to that of CRP; that of fibrinogen was not significant. <jats:italic>Chlamydia</jats:italic> <jats:italic>pneumoniae</jats:italic> but not <jats:italic>Helicobacter</jats:italic> <jats:italic>pylori</jats:italic> antibody titers significantly correlated with CRP plasma levels. </jats:p> <jats:p> <jats:italic>Conclusions</jats:italic> —In unstable angina, CRP may remain elevated for at ≥3 months after the waning of symptoms and is associated with recurrent instability. Elevation of acute-phase reactants in unstable angina could represent a hallmark of subclinical persistent instability or of susceptibility to recurrent instability and, at least in some patients, could be related to chronic <jats:italic>Chlamydia</jats:italic> <jats:italic>pneumoniae</jats:italic> infection. </jats:p>