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Stroke after acute myocardial infarction: relation to infarct size
Insights
Stroke risk after myocardial infarction is linked to infarct size. Patients with high peak creatine kinase (CK) levels, indicating larger infarcts, had a significantly higher stroke incidence. This finding helps identify patients needing prophylactic treatment.
Area of Science:
- Cardiology
- Neurology
- Biochemistry
Background:
- Acute myocardial infarction (AMI) is a leading cause of mortality and morbidity.
- Stroke is a significant complication following AMI, impacting patient outcomes.
- Identifying predictors of post-MI stroke is crucial for risk stratification and management.
Purpose of the Study:
- To investigate the relationship between myocardial infarct size and the incidence of stroke after AMI.
- To determine if peak serum enzyme concentrations can serve as a surrogate marker for infarct size and stroke risk.
- To identify patient subgroups at negligible risk for stroke who may not require anticoagulant prophylaxis.
Main Methods:
- Prospective study of 783 consecutive patients with AMI.
- Measurement of peak serum creatine kinase (CK) and aspartate transaminase levels.
- Correlation analysis between peak enzyme concentrations, cumulated enzyme levels, and infarct size.
- Incidence of stroke was calculated based on peak CK levels.
Main Results:
- 13 (1.7%) patients experienced stroke post-MI.
- Stroke incidence was significantly higher (4.7%) in patients with peak CK > 1160 IU/l compared to those with lower levels (0.2%).
- Peak enzyme concentrations strongly correlated with infarct size, suggesting they reflect the extent of myocardial damage.
Conclusions:
- Stroke risk following AMI is directly proportional to the size of the myocardial infarct.
- Patients with smaller infarcts (lower peak CK levels) have a low risk of stroke and may not need anticoagulant therapy.
- Peak serum enzyme levels are reliable indicators of infarct size and can aid in clinical decision-making regarding stroke prophylaxis.
Abstract:
In a consecutive series of 783 patients with acute myocardial infarction, 13 (1.7%) suffered a stroke. In all but one case the strokes occurred among the 255 patients whose peak creatine kinase (CK) concentrations fell in the upper third of the range of values (over 1160 IU/l, about eight times the upper limit of normal); the exception was a patient with a pre-existing ventricular aneurysm. The incidence of stroke in the patients with CK over 1160 IU/l was 4.7%, 24 times the incidence when peak CK was below this value (0.2%). Higher peak serum enzyme concentrations were associated with an even higher incidence of stroke. Comparison of peak enzyme concentrations with cumulated CK showed a close correlation (r = 0.90 with peak CK; r = 0.85 with peak aspartate transaminase), suggesting that the peak enzyme values reflected infarct size. Thus the risk of stroke after infarction was a function of the size of the myocardial infarct; two-thirds of the patients had negligible risk of stroke and did not need anticoagulant prophylaxis.