Myocardial infarction (AMI) is defined as the necrosis or death of part of the myocardium (heart muscle), in relation to a sustained obstruction of one of the coronary arteries (which supply oxygen to the heart). This is generally caused by the obstruction of a thrombus, by spasm or sustained contraction of the artery or by dissection (rupture of one of the layers of the artery).
Juvenile myocardial infarction is defined as infarction occurring before the age of 40 years. This represents about 2-8% of all AMI, a figure that is slowly increasing.
Analyzing the large series published on this type of patient, common variables are observed in all of them. These are: male gender (88%), smokers (80%), overweight (67%), elevated cholesterol (65%) and diabetes (17%). Among the acquired variables, family history of early coronary artery disease (that which appears before the age of 60 years) has a great influence.
Thus, only 3% of juvenile AMI are free of these conventional risk factors. It is also important to note that approximately 20% of juvenile AMI are associated with cocaine use.
Evolution of myocardial infarction
In most juvenile AMI only one of the three coronary arteries is affected (the left anterior descending coronary artery), the rest being healthy. This fact, together with the fact that young people usually do not have other associated chronic pathologies, means that the response to the different treatments is more effective and, therefore, that the short-term prognosis of juvenile AMI is usually very good and clearly better than in patients of more advanced age. However, the size of the AMI is usually larger, due to the fact that since it is not a slow and progressive pathology throughout life, collateral circulation (arteries that slowly open and irrigate an area with a lack of blood supply) has not been created. These collateral vessels develop when coronary artery blockages are slow and progressive. However, although initially the prognosis of juvenile AMI is better than that of the older population, this difference becomes less apparent when the long-term evolution is assessed.
Thus, since the subgroup of variables that usually concur in juvenile AMI is well defined, the prevention of these modifiable risk factors will undoubtedly have an impact on the reduction of this pathology.