A consensus statement on a new classification of acute myocardial infarction based on the degree of myocardial damage has been published. The new classification more accurately reflects the risks to patients.
The Canadian Cardiovascular Society (CCS) was the first to classify the stages of acute myocardial infarction (MI) based on the severity of damage to the heart muscle. The consensus statement was published in the Canadian Journal of Cardiology.
Experts analyzed the results of clinical studies over the past decade. Deterioration of remodeling and an increase in the frequency of adverse clinical outcomes with progressive myocardial damage have been shown. Current risk assessment and classification scales for myocardial infarction help determine patient management, but do not take into account the characteristics of tissue damage.
Based on years of data, CCS experts were able to identify four stages of tissue damage after a heart attack, with progressive severity:
- stage 1: interrupted myocardial infarction (no necrosis/minimal necrosis);
- stage 2: necrosis of cardiomyocytes without microvascular damage;
- stage 3: cardiomyocyte necrosis and microvascular obstruction;
- stage 4: cardiomyocyte necrosis, microvascular obstruction, and reperfusion hemorrhage.
Of particular importance is microvascular damage, the most severe form of which (hemorrhagic MI) leads to an expansion of the infarct zone and an increased risk of mechanical complications.
The authors believe that the new classification will help more accurately stratify the risk in patients with MI and develop new treatment methods specific to a particular stage of damage.