Objectives:We have demonstrated that patients after the Fontan operation have endothelial dysfunction and abnormal skeletal muscle hemodynamics, which were related to exercise intolerance. Fibrinogen is an independent cardiovascular risk factor causing inflammatory activation and endothelial dysfunction. The aim of this study is to investigate whether the fibrinogen level is associated with endothelial dysfunction and skeletal muscle hemodynamics in patients after the Fontan operation.
Methods: We studied 30 patients after the Fontan operation and an 10 age-matched control group. All subjects underwent cardiopulmonary exercise test with near-infrared spectroscopy monitoring on the vastus lateralis muscle. They also underwent endothelial function study with high-resolution ultrasound. Plasma fibrinogen level was measured using immunonephelometry.
Results: In patients without aortic desaturation, endothelium-dependent vasodilation(FMD) was diminished, but endothelium-independent vasodilation(NTG) was similar compared with controls. In patients with desaturation, both of FMD and NTG was diminished. In patients without aortic desaturation, fibrinogen level was high compared with patients with desaturation. Fibrinogen level was negatively correlated with FMD, but not with NTG. Increased fibrinogen level was associated with an attenuated postexercise resaturation of the working skeletal muscle. In multivariate analysis, an independent association was established between fibrinogen level and FMD.
Conclusion: The increased plasma fibrinogen level is associated, at least in patients without aortic desaturation, with endothelial dysfunction and abnormal skeletal muscle hemodynamics. This implies that increased fibrinogen level has a possible contribution to the pathophysiology of endothelial dysfunction and exercise intolerance in patients after the Fontan operation.