CARDIOVASCULAR JOURNAL OF AFRICA • SAHS Biennial Congress 16-18 September 2022 25 AFRICA Submission ID: 1364 Introduction Although an increased blood pressure (BP) response to a Na+ load is associated with an attenuated atrial natriuretic (ANP) response, Na+- sensitive hypertension is not associated with a volume overload. However, recent work provides the first evidence for a prevalent marked and sustained, volume-dependent form of primary hypertension in Africa. We aimed to determine whether systolic BP (SBP) control in sustained volume-dependent primary hypertension in Africa is associated with a blunted ANP relationship with indexes of volume load Methods Systemic hemodynamics (central pressure, echocardiographic aortic velocity and diameter measurements in the outflow tract), circulating ANP concentrations (ELISA assays) and renal function (24-hour urine collections [n=519]) were determined in a community of African ancestry (n=772). Results As compared to those with a controlled SBP, those with an uncontrolled SBP (n=198) showed lower ANP concentrations (p<0.005) despite a higher stroke volume (SV) and cardiac output (CO) (p<0.0001) and renal differences consistent with enhanced fluid retention. In those with a controlled SBP, fractional Na+ excretion (p<0.0005) and creatinine clearance (p<0.005) were inversely associated with ANP concentrations independent of several confounders. Moreover, in those with a controlled SBP, SV and CO (p<0.0001) were independently and positively associated with ANP concentrations. In addition, in those with a controlled SBP, ANP concentrations were independently and inversely associated with systemic vascular resistance (SVR)(p<0.0001) and aortic characteristic impedance (Zc)(p<0.005). By contrast, in those with uncontrolled SBP, no relationships between either SV (p>0.25), CO (p>0.29) or renal function (p>0.47) and ANP concentrations were noted. Furthermore, in those with an uncontrolled SBP, no relationships between ANP concentrations and SVR or Zc were observed (p>0.34). Conclusion In a population where primary hypertension is strongly volume-dependent, in those with an uncontrolled SBP an attenuated relationship exists between ANP and both renal and hemodynamic indexes of volume overload and the vascular effects of ANP. These data suggest that agents that target increases in circulating ANP concentrations may be essential in the management of volume-dependent primary hypertension. Name: Presenting Author Information Article Category Abstract Title Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. yusufmsuraj@kasu.edu.ng English Abstract Basic Sciences Attenuated Relationships Between Indexes of Volume Overload and Atrial Natriuretic Peptide in Uncontrolled, Sustained VolumeDependent Primary Hypertension. Author Affiliation: Email: Suraj M. Yusuf Authors Name & Surname Title Expertise Affiliation Email Country Suraj M. Yusuf Mr Cardiovascular Pathophysiologyy Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg yusufmsuraj@kasu.edu.ng South Africa Gavin R Norton Prof Cardiovascular Pathophysiology Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg gavin.norton@wits.ac.za South Africa Vernice R Peterson Dr Cardiovascular Pathophysiology Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg vernice.peterson@wits.ac.za South Africa ORAL PRESENTATION
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