Elevated levels of C-reactive protein at discharge in patients with unstable angina predict recurrent instability

Background-In a group of patients admitted for unstable angina, we investig ated whether C-reactive protein (CRP) plasma levels remain elevated at disc harge and whether persistent elevation is associated with recurrence of ins tability. Methods and Results-We measured plasma levels of CRP, serum amyloid A prote in (SAA), fibrinogen, total cholesterol, and Helicobacter pylori and Chlamy dia pneumoniae 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 patient s with discharge levels of CRP <3 mg/L but 69% of those with elevated CRP ( P<0.001) were readmitted because of recurrence of instability or new myocar dial infarction. New phases of instability occurred in 13% of patients in t he lower tertile of CRP (less than or equal to 2.5 mg/L), in 42% of those i n the intermediate tertile (2.6 to 8.6 mg/L), and in 67% of those in the up per tertile (greater than or equal to 8.7 mg/L, P<0.001). The prognostic va lue of SAA was similar to that of CRP; that of fibrinogen was not significa nt. Chlamydia pneumoniae but not Helicobacter pylori antibody titers signif icantly correlated with CRP plasma levels. Conclusions-In unstable angina, CRP may remain elevated for at greater than or equal to 3 months after the waning of symptoms and is associated with r ecurrent instability. Elevation of acute-phase reactants in unstable angina could represent a hallmark of subclinical persistent instability or of sus ceptibility to recurrent instability and, at least in some patients, could be related to chronic Chlamydia pneumoniae infection.