Anckle brachial index variation pre and post hemodialysis: relationship with body water, dialisate calcium concentration and autonomic nervous system

• Grant number: 13/01391-3
• Support Opportunities: Regular Research Grants
• Duration: June 01, 2013 - May 31, 2015
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Rosilene Motta Elias Coelho
• Grantee: Rosilene Motta Elias Coelho
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Despite all the technological advances of recent years, the mortality of dialysis patients remains unacceptably high. The traditional risk factors of cardiovascular disease (CVD) do not fully explain the high cardiovascular morbidity and mortality of individuals with chronic kidney disease (CKD), initiating hemodialysis (HD). The main cause of mortality in this population is cardiovascular, which is responsible for more than 50% of deaths among patients on dialysis. A research project conducted previously by the group of Nephrology, Hospital das Clinicas has proposed the use of ankle-brachial index (ABI), a simple and inexpensive method identifying patients at increased cardiovascular risk in a population of incident patients on hemodialysis. The ABI is defined as the ratio of the highest systolic blood pressure on the lower limbs and the higher systolic blood pressure in the upper limbs. The abnormal ABI (higher or low than normal range), showed a good marker of mortality risk among incident patients on hemodialysis. However, there was ABI variability in some patients, who switched from high to normal or low ABI when comparing pre and post dialysis measures. Those patients who had a higher variability of ABI had lower survival. It is known that sympathetic over activity can increase intradialytic blood pressure and it has an important role in generating inter dialytic hypertension. The autonomic nervous system may be implicated in this variability and may, at least partly, explain the intra-dialytic pressure fluctuations. In addition, markers of vascular calcification as osteoprotegerin and fetuin may contribute to the stiffness of the vessels interfering on the blood pressure fluctuations during the hemodialysis. Based on this, we intend to study pre and post dialysis ABI variation according to simultaneous variations of the autonomic nervous system by studying heart rate variability, markers of blood volume by bioelectrical impedance, hormonal markers as aldosterone and renin, as well as markers of vascular calcification as osteoprotegerin and fetuin. (AU)