Predictive value of brachial reactive hyperemia and flow-mediated dilation in stable coronary artery disease

BACKGROUND: The purpose of this study was to determine the predictive value of a single measurement of reactive hyperemia (RH) and brachial flow-mediated dilation (FMD) in patients with established stable coronary artery disease (CAD). METHODS: RH and brachial artery FMD were ultrasonographically measured in 325 patients with stable CAD. Patients were followed for cerebro-cardiovascular events. The median follow-up was 3.7 years (range 0.01-5.7 years). RESULTS: Sixty-seven patients (20.6%) had an cerebro-cardiovascular event. Patients with subsequent events had lower FMD (4.9 +/- 3.3% versus 6.3 +/- 3.5%, p=0.003), higher brachial artery resting diameter (5.1 +/- 0.7mm versus 4.8 +/- 0.7mm, p=0.002) and lower NMD (11.2 +/- 5.1% versus 12.8 +/- 5.4%, p=0.02), while the mean hyperemic flow velocity and shear stress did not differ from patients without cerebro-cardiovascular events. Cox proportional hazard model adjusted for sex, age, BMI, and traditional cardiovascular risk factors revealed a hazard ratio of 0.84 for lower FMD (p=0.01). CONCLUSIONS: We conclude that single spot measurements of peak RH do not provide long-term prognostic information, but evaluation of conduit artery FMD predicts long-term cerebro-cardiovascular events in patients with stable CAD. The prognostic value of FMD is incremental to traditional cardiovascular risk factors and may therefore be of clinical importance.