Persistent atrial fibrillation in the elderly. A possible association with arterial stiffness, hyperuricemia and chronic inflammation

Background: The prevalence of atrial fibrillation (AF) has an age-related increase. Arterial stiffness (AS) follows the same trend. The Cardio-Ankle Vascular Index (CAVI) is a non-invasive tool for an accurate and fast AS evaluation. Purpose: Aims of this study were to identify clinical predictors of AS in elderly patients with persistent AF and to assess the interaction of arterial properties and of hyperuricemia (≥6.0 mg/dL or allopurinol use) with left atrial dilatation. Methods: We studied all the consecutive patients undergoing elective electrical cardioversion (ECV) of persistent AF in a Day-Hospital setting. At baseline, all subjects were studied using the traditional clinical evaluation integrated with specific tests of the multidimensional geriat- ric assessment and with the analysis of some of the markers of chronic inflammation (interleukin-6, IL-6, and osteoprotegerin, OPG). CAVI and echocardiography variables were obtained after the ECV, immediately before the discharge from the Day-Hospital. Results: Initial population consisted of 96 patients; 12 (12.5%) of them were excluded from the study for a clearly abnormal Ankle-Brachial Index (ABI; <0,9). Among the remaining 84 patients (age: 76 ± 8 years; men: 67.9%; hyperuricemia: 46.4%; left atrium diameter – LAD: 53 ± 7 mm), 39 (46.4%) had AF without an underlying structural heart disease (tachycardia-bradycardia syndrome, lone AF); in the other 45 cases (53.6%), AF was related to hypertension, coronary artery disease or heart failure. ECV was successful in 94% (N = 79/84) of patients. In multivariate analysis (R = 0.533, p < 0.001) age, heart rate, aortic aneurysm and/or peripheral arteriopathy without ABI alterations were asso- ciated with CAVI. In a second multivariate model (R = 0.537, p = 0.005), including patients with inflammatory markers evaluation, CAVI was associated with age and OPG. Regarding the second aim of the study, in multivariate analysis (R = 0.485, p < 0.001), LAD showed a direct association with body weight, CAVI – our measure of AS - and hyperuricemia. Furthermore, IL-6 levels were positively correlated with uric acid (p = 0.006). Conclusions: In elderly patients with persistent AF, AS correlates with age and heart rate. OPG, an inflammatory marker, seems to be associated with a reduced arterial distensibility, possibly representing a link between vascular properties and AF genesis. LAD correlates to body weight, AS and uric acid levels. Specific clinical studies should confirm these results and verify if they are simple statistic associations or if they could effectively explain part of AF pathogenesis and its relapses.