CARDIOVASCULAR JOURNAL OF AFRICA • SAHS Biennial Congress 16-18 September 2022 23 AFRICA Submission ID: 1363 Introduction Although renal mechanisms are well-recognised as contributing to primary hypertension, this has until recently, never been demonstrated to translate into sustained volume-dependent hypertension. However, recent studies indicate that in Africa, renal-related sustained volumedependent primary hypertension is the dominant form of hypertension. The exact mechanisms through which a volume load determines increases in BP is nevertheless uncertain. We therefore aimed to identify the relative contribution of volume-dependent increases in aortic reservoir function, assessed from late systolic ejection volume, versus pressure wave (forward and backward) effects to variations in pulse pressure (PP) and LV mass index (LVMI) in a community with volume-dependent primary hypertension. Methods From central pressure, aortic velocity and diameter measurements (outflow tract) and echocardiography, we determined LV ejection dynamics, arterial wave morphology and LVM in an African community (n=734). Results LV end diastolic volume and circulating atrial natriuretic peptide concentrations were independently associated with both peak aortic flow (Q) and a shift in ejection volume from early (up to the first systolic shoulder, P1) (V1) to late (between P1 and peak PP) (V2) systole (p<0.0001). Independent of the component of forward wave pressures generated by the product of Q and characteristic impedance (Zc) to flow (PQxZc) and backward wave pressures (Pb), through V2 effects, V2/V1 was independently associated with peak central arterial PP (PPc)(p<0.0001). Relationships between V2/V1 and PPc were independent of stroke volume (SV). The impact of V2/V1 on PPc was second (standardized β-coefficient=0.166±0.017) to max PQxZc (0.417±0.030, p<0.001) and similar to Pb (0.244±0.034, p<0.0001). Independent of PQxZc, Pb and SV, through V2 effects, V2/V1 was also independently associated with LVMI and mean wall thickness (MWT) (p<0.0001), and in the same regression models, PQxZc (p<0.01), but not Pb showed significant relationships with LVMI. Conclusion In a community with prevalent and sustained volume-dependent primary hypertension, volume-dependent increases in reservoir function (late systolic ejection volume) contribute less than pressure waves to PP, but reservoir function is a primary determinant of LV structure. Targeting volume overload is essential in the management of volume-dependent 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. gavin.norton@wits.ac.za English Abstract Population Sciences Relative Impact of Volume-Dependent Variations in Aortic Reservoir Function Versus Pressure Wave Effects on Pulse Pressure and Cardiac Mass at a Community Level. Author Affiliation: Email: Gavin R Norton Authors Name & Surname Title Expertise Affiliation Email Country Gavin R Norton Prof Cardiovascular Physiology 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 Suraj M. Yusuf Mr Cardiovascular Physiology Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg yusufmsuraj@kasu.edu.ng South Africa Vernice R Peterson Dr Cardiovascular Physiology 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
RkJQdWJsaXNoZXIy NDIzNzc=