1.4 Can AIx Predict All-Cause Mortality in a General Population?

Background Aortic augmentation Index (AIx) is a measurement of pulse wave reflections and an indirect measure of arterial stiffness. AIx predicts all-cause mortality and CV-mortality in selected patient group with endstage renal failure and in patients undergoing percutaneous coronary intervention (PCI). The objective of this study was to analyse AIx as an independent predictor of all-cause mortality in a population without known cardiovascular disease (CVD). Methods This study is based on 3,432 subjects from the 4 th survey of the Copenhagen City Heart Study with AIx measured non-invasively. During follow-up (mean 6.5 years) 334 persons died. AIx was divided in tertiles with the lowest tertile as reference. Mortality risk was analyzed by Cox proportional hazard models with age as the underlying time scale adjusting for heart rate, height, weight, blood pressure, total-cholesterol, smoking, alcohol, diabetes, education, physical activity and predisposition to CVD. Results AIx significantly predicted all-cause mortality but in opposite direction for men and women. Men Women HR 95 % CI HR 95 % CI AIx – intermediate vs. low tertile 1.86 1.06–3.27 0.66 0.44–0.99 AIx – high vs. low tertile 2.30 1.24–4.24 0.53 0.34–0.82 Conclusion High AIx was associated with increased mortality in men but decreased in women. The surprising finding in women may be related to gender related difference in the arterial properties measured by AIx as also reflected by AIx reaching a plateau in women approximately ten years earlier than men. Conclusion High AIx increased the risk of mortality in men but the opposite was seen in women. This can be explained by a curvilinear AIx/age relationship more pronounced in women where old women may have decreased pulse wave reflections in accordance with findings in the Framingham studies.