Background: Improved exercise capacity in chronic heart failure(CHF) has been attributed to restoration of endothelial function. ACE inhibitors as well as beta blockers have previously been shown to enhance endothelial function and exercise capacity. The aim of this study was to determine whether short-term improvement in submaximal exercise capacity induced by optimized therapy with ACE inhibitors in combination with beta blockers is associated with restoration of endothelial function in CHF patients. Methods: Thirty-three patients with CHF were evaluated: six-minute walk test, NYHA class, brain natriuretic peptide(BNP), big Endothelin-1(bigET-1) and flow-mediated vasodilation(FMD) of the brachial artery were assessed at baseline and after a 3-month period of optimized neurohormonal therapy. Two groups were formed retrospectively based on the changes in submaximal exercise capacity(responders and nonresponders). Results: Optimization of neurohormonal therapy was comparable between groups. Responders(n=17) revealed a significant increase in walking distance(304± 109 to 441± 75 m; p< 0.01), which was paralleled by a decrease in NYHA class(2.7± 0.6 to 2.0± 0.4; p< 0.01), BNP(484± 454 to 243± 197 pg/ml; p< 0.01), and bigET-1(2.0± 0.9 vs. 1.5± 0.6 fmol/ml; p=0.04). By contrast, the latter variables did not change in non-responders. Improvement in functional capacity in responders was associated with an increase in FMD(8.2± 3.9% to 11.0± 5.6% ; p< 0.05). Increments in FMD were directly correlated with increases in walking distance(r=0.34; p< 0.05). Conclusion: Short-term improvement of submaximal exercise capacity in CHF patients following optimized therapy with ACE inhibitors and beta blockers is associated with restoration of endothelial function in conduit arteries.
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