Ferrokinetic studies in acute myocardial infarction

Iron deficiency and all-cause mortality after myocardial infarction

BACKGROUND

Data on the clinical significance of iron deficiency (ID) in patients with myocardial infarction (MI) are conflicting. This may be related to the use of various ID criteria. We aimed to compare the association of different ID criteria with all-cause mortality after MI.

METHODS

Consecutive patients hospitalized for their first MI at a large tertiary heart center were included. We evaluated the association of different iron metabolism parameters measured on the first day after hospital admission with all-cause mortality.

RESULTS

From the 1,156 patients included (aged 64±12 years, 25 % women), 194 (16.8 %) patients died during the median follow-up of 3.4 years. After multivariate adjustment, iron level ≤13 µmol/L (HR 1.67, 95 % CI 1.19-2.34) and the combination of iron level ≤12.8 µmol/L and soluble transferrin receptor (sTfR) ≥3 mg/L (HR 2.56, 95 % CI 1.64-3.99) termed as PragueID criteria were associated with increased mortality risk and had additional predictive value to the GRACE score. Compared to the model including iron level, the addition of sTfR improved risk stratification (net reclassification improvement 0.61, 95 % CI 0.52-0.69) by reclassifying patients into a higher-risk group. No association between ferritin level and mortality was found. 51 % of patients had low iron levels, and 58 % fulfilled the PragueID criteria.

CONCLUSION

Iron deficiency is common among patients with the first MI. The PragueID criteria based on iron and soluble transferrin receptor levels provide the best prediction of mortality and should be evaluated in future interventional studies for the identification of patients potentially benefiting from intravenous iron therapy.

Elevated serum ferritin level in acute myocardial infarction

Serum ferritin level was determined in 20 patients with acute myocardial infarction (AMI) during the first 10 days post infarction. Starting on the second day, a gradual increase in serum ferritin level was detected, reaching a maximum of four times the initial level on the sixth day after the infarction. In addition, a significant increase in ferritin content was found in the peripheral blood monocytes on the fifth day after the event. The control group comprised six patients suffering from chest pains not due to AMI. In all of them the serum ferritin level was found to be within normal limits. Peripheral blood monocytes derived from healthy individuals incubated with hydrocortisone, showed a significant enhancement of their ferritin content, a finding suggesting that these cells activated by steroids during stress could be a source of the increased serum ferritin level following AMI. It is concluded that measurement of serum ferritin may be used as a complementary tool for confirming the diagnosis of AMI.