C‐reactive protein during and after myocardial infarction in relation to cardiac injury and left ventricular function at follow‐up

BACKGROUND: Acute myocardial infarction (MI) invokes a large inflammatory response, which contributes to myocardial repair. HYPOTHESIS: We investigated whether C‐reactive protein (CRP) measured during MI vs at 1 month follow‐up improves the prediction of left ventricular (LV) function. METHODS: We prospectively enrolled 131 consecutive patients with acute MI and without non‐cardiovascular causes of inflammation. We correlated admission and peak levels of CRP during hospitalization and high‐sensitivity (hs) CRP at 1 month follow‐up with markers of cardiac injury. Clinical follow‐up and echocardiography for LV function were performed at a mean of 17 months. RESULTS: Median CRP levels were 1.89 mg/L on admission with MI, peaked to 12.10 mg/L during hospitalization and dropped to 1.24 mg/L at 1 month. Although admission CRP levels only weakly correlated with ejection fraction in the acute phase of MI (coefficient −0.164, P = 0.094), peak CRP was significantly related to ejection fraction (coefficient −0.4, P < 0.001), hsTroponin T (0.389, P < 0.001), and white blood cell count (0.389, P < 0.001). hsCRP at 1 month was not related to the extent of acute cardiac injury. These findings were replicated in an independent cohort of 57 patients. Peak CRP predicted LV dysfunction at follow‐up (OR 11.0, 3.1‐39.5 per log CRP, P < 0.001), persisting after adjustment for infarct size (OR 5.1, 1.1‐23.6, P = 0.037), while hsCRP at 1 month was unrelated to LV function at follow‐up. CONCLUSIONS: hsCRP 1 month post‐MI does not relate to acute cardiac injury or LV function at follow‐up, but we confirm that peak CRP is an independent predictor of LV dysfunction at follow‐up.