The area under curve for time-course analysis parameters is associated with abdominal aortic aneurysms and the severity of peripheral artery disease in men

Background: Abdominal aortic aneurysm (AAA) and peripheral artery disease (PAD) are associated with vascular endothelial dysfunction. To date, flow-mediated vasodilatation (FMD) and nitroglycerin-mediated vasodilatation (NMD) have been used to evaluate vascular function. Recently, parameters of time-course analysis have been proposed as useful evaluations for arteriosclerotic diseases. In this study, the correlation between the parameters of time-course analysis, to the degree of vascular endothelial damage in AAA and PAD, together with their applicability as a vascular function test, was investigated.Methods: Brachial artery vasoreactivity was assessed in male patients with AAA (n= 150) and PAD (n= 50). The percentage change in peak diameters (Delta FMD and Delta NMD), the time to diameter change, the time to peak diameter from the diameter change, the blood flow decay time constant, the area under the curve (AUC), the maximum dilation rate and the extended time constant were measured.Results: Among the groups of aneurysm diameter in AAA, the FMD-AUC was highly different (p=.01), while the Delta FMD was not significantly different (p=.36). Among the Fontaine stages in PAD, the FMD-AUC was inversely associated with severity (p=.01) although the Delta FMD was not significantly different (p=.71). Among the Fontaine stages, the NMD-AUC was also inversely associated with severity (p=.03) although the Delta NMD was not significantly different (p=.11).Conclusion: This study suggests that FMD-AUC and NMD-AUC are useful for estimating vascular endothelial and vascular smooth muscle dysfunction, serving as supplementary markers for the diagnosis and evaluation of PAD and AAA.