Circulating fibrocyte levels correlate with infarct size in patients with ST elevation myocardial infarction treated with primary percutaneous coronary intervention()

STUDY OBJECTIVE: Infarct size is a strong predictor of outcomes after ST elevation myocardial infarction (STEMI). Circulating fibrocytes are bone marrow-derived progenitor cells associated with fibrotic processes. We tested whether fibrocytes correlate with infarct size in STEMI patients treated with primary percutaneous coronary intervention (PCI). DESIGN: Prospective observational study. SETTING: Academic medical center. PARTICIPANTS: Subjects with STEMI treated with primary PCI. INTERVENTIONS: Peripheral blood draw and cardiac magnetic resonance imaging (CMR). MAIN OUTCOME MEASURE: Correlation of fibrocyte levels with infarct size. METHODS: Peripheral blood fibrocytes were quantified at discharge from STEMI hospitalization and at 6 months follow-up using flow cytometry. Infarct size was determined within 2 weeks of discharge and at 6 months follow-up using late gadolinium enhancement on CMR. RESULTS: Among 14 patients (median age 54 years, 79% men) with STEMI, there was a statistically significant positive correlation between fibrocyte levels at 6 months and 6-month infarct size on CMR (r = 0.58, p = 0.031). In addition, there was positive correlation between peak troponin I level (r = 0.85, p < 0.001), and white blood cell count (r = 0.55, p = 0.042) during the hospital stay and 6-month infarct size on CMR. CONCLUSIONS: Circulating fibrocytes measured 6 months after STEMI positively correlate with 6-month infarct size assessed by CMR.