Abstract 1188: Prognostic Significance of Markers of Vascular Health: Long-term Results From the Firefighters And Their Endothelium (FATE) Study
Background: Impaired brachial flow-mediated dilation (FMD) has been shown to be predictive of CV events in high-risk cohorts. The purpose of the FATE study was to determine the prognostic significance of endothelial function and other vascular markers in lower risk, middle-aged men.
Methods: The cohort consisted of 1574 Canadian male firefighters (age 49.4 yrs) free of vascular disease. Primary markers of vascular health included FMD and its microvascular stimulus, hyperemic velocity. Secondary end-points included carotid intimal-media thickness (IMT) and C-reactive protein (hs CRP). Cox proportional hazard models evaluated the relationship between vascular markers, standard risk factors and a composite CV end-point of time to cardiac death, MI, stroke, revascularization or angina.
Results: Subjects had low-medium Framingham 10 year risk (7.9 %). CV events occurred in 71 subjects (111 events) over a mean follow-up of 7.2± 1.7 yrs. There was no difference in FMD (8.3 ±3.8 vs 8.6 ±4.1 % P=NS) between those with and without events. Hyperemic velocity, carotid IMT and hs-CRP were all independently related to adverse events (table 1⇓). In a multivariate analysis including all vascular markers, predictors of CV events included hyperemic velocity (p<0.0001), age (p=0.0002), total cholesterol (p=0.007), carotid IMT (p=0.004), but not hs-CRP. The addition of hyperemic velocity to Framingham Risk Score increased the ROC c statistic from 0.75 to 0.77 and resulted in a net reclassification index of 6.4% and net clinical reclassification index of 15.3%.
Conclusion: In healthy middle aged men, hyperemic velocity, the stimulus for FMD, but not FMD itself was a significant risk marker for adverse CV outcomes. This was additive to traditional risk factors and carotid IMT. This newly described marker of microvascular function may provide prognostic information for the risk stratification of low-medium risk men.