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[Serum C3 as a screening factor in the primary prevention of myocardial infarct]
A Muscari1, G Massarelli, G M Puddu
1Istituto di Patologia Speciale Medica e Metodologia Clinica, Università degli Studi, Bologna.
Insights
Serum C3 measurement can improve the selection of men for diet or drug therapy in myocardial infarction primary prevention. This approach identifies more individuals needing treatment and captures a higher percentage of future heart attacks compared to standard guidelines.
Area of Science:
- Cardiovascular Medicine
- Immunology
- Biochemistry
Context:
- Atheroma formation involves macrophages, which synthesize C3, a complement system component.
- Recent studies indicate a link between serum C3 levels and myocardial infarction risk in men.
- Traditional myocardial infarction prevention guidelines rely on LDL cholesterol levels and risk factors.
Purpose:
- To evaluate the utility of serum C3 levels in conjunction with LDL cholesterol for selecting male subjects for primary prevention therapies against myocardial infarction.
- To compare the efficacy of C3-based treatment selection models against standard National Cholesterol Education Program guidelines.
Summary:
- This study analyzed 332 men aged 45-75 without prior cardiovascular disease, measuring serum C3 and following them for 4 years, during which 11 experienced myocardial infarction.
- Two novel treatment selection models incorporating serum C3 levels (Model B and Model C) were compared to standard criteria (Model A).
- Model B and C significantly reduced the percentage of men recommended for diet therapy (27% and 45% vs. 71% for Model A) while including a higher proportion of future myocardial infarction cases (82% and 100% vs. 82%).
Impact:
- C3-based criteria may enable more precise identification of individuals requiring intervention for myocardial infarction primary prevention.
- These findings suggest a potential refinement of current cardiovascular risk stratification and treatment initiation protocols.
- The study highlights the role of complement system components in cardiovascular disease and their potential as biomarkers.
Abstract:
This study addresses the possible use of serum C3 (third component of the complement system) to select the subjects to be submitted to diet or drug therapy in the primary prevention of myocardial infarction. C3 is synthesized by macrophages, which are the main cells involved in atheroma formation, and an association between serum C3 and the risk of myocardial infarction has recently been found in the male sex. We have studied 332 men aged 45-75 years, who had no cardiovascular disease at any time before blood sampling. In their sera C3 measurement was performed by nephelometry. The 4 year follow-up was known for all of these subjects: in particular, 11 had a myocardial infarction. The average LDL cholesterol (LDL-C) levels in the whole population were rather high (162.2 +/- 45.8 (1 SD) mg/dl). As standard treatment criteria (A), those suggested for primary prevention by the National Cholesterol Education Program panel of experts were adopted: diet if LDL-C > or = 160 mg/dl, or LDL-C > or = 130 mg/dl + 2 additional risk factors; drugs if, after diet, LDL-C > or = 190 mg/dl, or LDL-C > or = 160 mg/dl + 2 risk factors. This scheme was compared with two models of treatment which included the measurement of serum C3. According to the first of such models (B), diet should be prescribed when C3 levels are within the high third of distribution (> or = 135 mg/dl) with LDL-C > or = 100 mg/dl, and drugs should be given if, after diet, serum C3 is > or = 135 mg/dl with LDL-C > or = 130 mg/dl. The second model based on C3 (C) is of combined type since, in addition to model B criteria, it also suggests to prescribe a diet if LDL-C > or = 190 mg/dl, while drugs should be given if, after diet, LDL-C levels persist > or = 190 mg/dl. The effect of diet has been simulated by assuming a 10% decrease in LDL-C levels. According to all of these criteria, the subjects to treat with diet with the models A, B and C would have been, respectively, 71, 27 (p < 0.0001 vs mod A) and 45% (p < 0.0001 vs mod A) of the whole population, including among them, respectively, 82, 82 and 100% of the future myocardial infarctions. After diet, according to the three models A, B and C -29, 20 (p = 0.0117 vs mod A) and 30% of the whole population should have been treated with drugs, including, respectively, 54, 64 and 82% of the future myocardial infarctions. In conclusion, the use of criteria based on serum C3, with respect to more traditional guidelines, might allow a more precise identification of the subjects to submit to diet and drug treatment in the primary prevention of myocardial infarction.