Background: Risk stratification for subsequent cardiovascular events following a myocardial infarction (MI) is an important area of research. Previous findings indicate flow-mediated dilatation (FMD) may be a valuable prognostic indicator. This study investigates the prognostic value of FMD in patients suffering an uncomplicated MI.
Methods: One hundred and seventy nine post-MI patients [110 male/69 female, mean age: 64.8+/-10.0 years, ejection fraction: 51.9+/-12.2%] were included in this analysis. Ultrasound images of the brachial artery were used to determine FMD following reactive hyperemia. Subjects were tracked for subsequent cardiovascular events [myocardial infarction, heart failure, additional interventions (percutaneous coronary intervention, coronary artery bypass)] following data collection via medical chart review.
Results: There were 45 subsequent cardiovascular events during a mean tracking period of 13.7 (+/-9.5) months. Receiver operating characteristic (ROC) curve analysis revealed a diagnosis of diabetes (ROC area: 0.67, p=0.001, 95% confidence interval: 0.58-0.77) and percent change in arterial diameter (ROC area: 0.63, p=0.01, 95% confidence interval: 0.53-0.73, optimal threshold: <or=/>4.5%) were prognostically significant. Kaplan-Meier analysis revealed the event-free survival rate for subjects without diabetes and an arterial diameter change >4.5%, without diabetes and percent change in arterial diameter <or=4.5%, with diabetes and percent change in arterial diameter >4.5% and with diabetes and percent change in arterial diameter <or=4.5% was 88.7%, 78.4%, 67.7% and 38.5%, respectively (Log-rank: 24.9, p<0.0001).
Conclusions: Non-invasive FMD is a potential risk factor after MI and may add information to conventional risk stratification. This will need to be tested in further studies.