CardioVascular Journal of Afr ica (off icial journal for PASCAR) www.cvja.co.za Biennial Congress Southern African Hypertension Society Controlling Hypertension in Southern Africa: The New Frontier 16-18 August 2024 ABSTRACT BOOKLET 35
Disclaimer The Abstracts for the Southern African Hypertension Society was reviewed by the SAHS Scientific Committee and not by the Editor-in-Chief, Regional Editors or reviewers of the Cardiovascular Journal of Africa. Only accepted abstracts are published.
Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 3 AFRICA To all our researchers, On behalf of the Southern African Hypertension Society (SAHS), I want to extend our heartfelt thanks to all researchers submitting your abstract and your commitment of time to the important field of hypertension research. Your contributions are invaluable and play a crucial role in advancing our understanding and treatment of hypertension. We deeply appreciate the effort and dedication you have put into your research. Your work not only contributes to the broader scientific community but also holds the potential to improve countless lives by enhancing our ability to manage and treat hypertension effectively. The quality and diversity of the abstracts we received are truly impressive. Each submission reflects the hard work, innovative thinking, and expertise that you bring to this field. Your research not only addresses critical questions but also paves the way for future discoveries and advancements. Your research, as part of the scientific programme, has significantly advanced multidisciplinary learning in the field of hypertension and “Controlling Hypertension in Southern Africa “ Thank you once again for your dedication and commitment to hypertension research. Your work is making a difference, and we are grateful for your participation. Prof Nash Ranjith SAHS President Thank you
AFRICA Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 4 ORAL PRESENTATION Entry Id Page no Name: 1614 5 Siluleko Mkhize 1617 6 Pheletso Letuka 1619 7 Dr Lisa Uys 1622 8 Gontse Mokwatsi 1624 9 Nonkululeko Navise 1629 10 Grace Tade 1630 12 Zak Coetzee 1631 13 Marcus N Lebelo 1633 14 Chanelle Volschenk 1634 15 Katleho Khanye 1636 16 Kellicia Courtney Govender 1644 17 Dr Rohan Lutchman 1645 18 Grace Tade 1646 19 Shayur Arijune, Angela J Woodiwiss, Nonhlanhla Mthembu, Hamza Bello, Glenda Norman, Suraj M Yusuf, Vernice R Peterson 1649 20 Philimon Gona POSTER PRESENTATION Entry Id Page no Name: 1615 21 Dr Ngobese 1618 22 Dr Adamu Jibril Bamaiyi 1620 24 Marcus N Lebelo 1625 25 Dr Aniekan Edet 1632 26 Padiso Matsole 1638 27 Refentshe Amandu’s Nthlane 1639 30 Dr Dalene De Beer 1641 31 Morongwa Ngobese 1642 32 Kealeboga M Fako 1643 33 Kganetso Sekome 1647 34 Hatija Faria
Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 5 AFRICA Submission ID: 1614 Introduction Hypertension drives the development of concentric left ventricular hypertrophy (LVH). However, the relative contribution of pentraxin-3 (PTX-3) in the hypertrophic response to pressure overload has not been adequately elucidated. Aim: We sought to investigate the role of PTX-3 in the development of LVH in spontaneously hypertensive rats (SHR), untreated and treated with either captopril (an ACE inhibitor) or hydralazine (a non-specific vasodilator). Methods Three-month-old SHR received either 20 mg/kg/day hydralazine (SHR+H, n=6), 40 mg/kg/day captopril (SHR+C, n=6), or plain gelatine cubes (untreated SHR, n=7) orally for 4 months. Wistar Kyoto rats (WKY, n=7) were used as the normotensive controls. Blood pressure (BP) was measured using the tail-cuff method. At termination, cardiac geometry and function under anaesthesia were determined using M-mode echocardiography. Following termination, the blood, and the left ventricles (LV) were sampled. Circulating levels of inflammatory markers were measured in plasma by ELISA and relative mRNA expression of PTX-3 was determined in the LV by RT-PCR. Results Untreated SHR exhibited greater systolic BP and relative wall thickness (RWT) compared to WKY. Captopril and hydralazine normalised BP but only captopril reversed hypertrophic changes in SHR. Circulating PTX-3 levels were elevated in untreated SHR but normalised with captopril and hydralazine. Circulating PTX-3 was positively associated with systolic BP but lacked independent relations with indices of LVH. In addition, LV relative mRNA expression of PTX-3 was similar between the groups. Conclusion PTX-3, a circulating marker of hypertension, may not be involved in the development of LVH in SHR. Name: Presenting Author Information Article Category Abstract Title Integrated Molecular Physiology Research Initiative, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand siluleko.mkhize@wits.ac.za English Abstract Students - Currently enrolled postgraduate students Involvement of pentraxin-3 in the development of hypertension but not left ventricular hypertrophy in spontaneously hypertensive rats Author Affiliation: Email: Siluleko Mkhize Science Theme Basic Author Name & Surname Title Expertise Affiliation Email Country Siluleko Mkhize Mr Molecular & Cellular Molecular Physiology Research Initiative siluleko.mkhize@wits.ac.za South Africa ORAL PRESENTATION
AFRICA Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 6 Submission ID: 1617 Introduction Resistant hypertension (RH) is defined as blood pressure that remains above goal despite concurrent use of three or more antihypertensive agents of different classes. Patients with RH are at a greater risk of cardiovascular (CV) complications compared with patients who have controlled hypertension. The high CV risk is attributable, in part, to long-standing, poorly controlled hypertension. There is a paucity of data on RH and its association to cardiovascular disease (CVD) in Africans. This study defines the phenotype of RH using cardiovascular magnetic resonance imaging. Our findings may contribute to improved understanding of the pathophysiology of this disease in Africans. Methods The cardiovascular phenotype of patients with resistant uncontrolled hypertension (RUH) were compared to patients with resistant controlled hypertension (RCH) and matched controls, using cardiovascular magnetic resonance (CMR) and other imaging modalities. 61 participants (30 RUH, 20 RCH and 11 matched controls) underwent blood pressure measurements, CMR, echocardiography, electrocardiography, applanation tonometry and serum biomarker analysis. Results Patients with RUH were obese (73% vs 55%, p=0.01), with a history of retinopathy (47% vs 20%, p=0.001), albuminuria (33% vs 10%, p=0.002), myocardial infarction (10% vs 0%, p=0.009) and stroke (13.3% vs 0%, p=0.006). They had a longer duration of hypertension (10.5±10.7 vs. 3.6±3.4, p=0.02) with treatment that included an ACE-inhibitor (90% vs. 58%, p=0.01). They had higher mean arterial BP (115±17 vs 101±15 mmHg, p= 0.004), lower small artery elasticity (4.1±2.1 vs. 6.9±3.6ml/mmHgx100, p<0.001) and higher systemic vascular resistance (1754±418 vs. 1363±371 dyneXsecXcm-5, p=0.002) compared to patients with RCH. Patients with RUH and RCH compared to healthy controls on echocardiogrpahy had increased interventricular septum thickness (1.3±0.20 vs 1.2±0.17 vs 0.93±0.17), left ventricular (LV) posterior wall thickness (1.19±0.20 vs 1.08±0.16 vs 0.8±0.14, p<0.001) and increased deceleration time (200±43.7 vs 192±15.8 vs 167±7.9, p=0.02). On ECG, patients with RUH and RCH had a longer QRS duration (96.11±11.9 vs 95±15.9 vs 84±9.4, p=0.03) and on CMR, they had a higher LV stroke volume (vs 105±26 vs 100±21 vs 84±20, p=0.047), Native T1 molli (1243±44 vs 1236±57 vs 1184±23, p=0.002) and peak systolic circumferential strain rate (-1.3±0.3 vs -1.2±0.2 vs -1.1±0.3, p=0.048 ). Conclusion Vascular remodelling in RUH predates cardiovascular morbidity and can be used as an early indicator of remodelling using multimodal imaging. Name: Presenting Author Information Article Category Abstract Title University of Cape Town, Department of Medicine ltkphe001@myuct.ac.za English Abstract Students - Currently enrolled postgraduate students Vascular dysfunction and preclinical cardiovascular remodelling in resistant uncontrolled hypertension characterised by cardiovascular magnetic resonance and multi-modal imaging: a cross-sectional study Author Affiliation: Email: Pheletso Letuka Science Theme Clinical Authors Name & Surname Title Expertise Affiliation Email Country Pheletso LetukaFalatsi Mrs Cardiovascular Physiology Department of Medicine, University of Cape Town ltkphe001@myuct.ac.za South Africa Petronella Samuels Mrs Radiography Cape Universities Body Imaging Centre, University of Cape Town petronella.samuels@uct.ac.za South Africa Stephen Jermy Mr Biomedical engineering Cape Universities Body Imaging Centre, University of Cape Town stephen.jermy@uct.ac.za South Africa Hadil Saad Dr Medicine Department of Medicine, University of Cape Town hadil.saad@charite.de Germany Brian Rayner Prof Nephrology Department of Medicine, University of Cape Town brian.rayner@uct.ac.za South Africa Ntobeko Ntusi Cardiology Department of Medicine, University of Cape Town ntobeko.ntusi@uct.ac.za South Africa ORAL PRESENTATION
Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 7 AFRICA ORAL PRESENTATION Submission ID: 1619 Introduction Depressed baroreceptor sensitivity (BRS) is evident in hypertension, reported as a critical contributor to cardiovascular disease (CVD) risk in adults. Moreover, poor CVD outcomes are imminent pertaining to chronic kidney disease and heart failure. However, if the same associations can be discerned in younger cohorts are unknown. Our study therefore aimed to determine if BRS relates to kidney function and family history (FH) of CVD and lifestyle risk factors in prepubescent boys stratified by blood pressure status. Methods Our study included 40 black and 41 white boys (aged 6 – 8 years) from North-West, South Africa. Anthropometric and basic demographic data were collected (including information on FH. Cardiovascular measures included blood pressure (BP) and beat-to-beat Finometer measurement for BRS calculation. Urine samples were analysed to determine the albumin-to-creatinine ratio (ACR), indicative of kidney function. For statistical analysis, stratification was based on BP status of normal or elevated. Results The elevated BP group (n=37; 46%) had more Black boys (p=0.003). BRS (p=0.56) and ACR (p=0.92) were comparable between the normal and elevated BP groups. Within the normal BP group, BRS correlated with ACR in single (r=-0.43; p=0.006) and partial (r=-0.41; p=0.01) regression analysis after adjusting for ethnicity, age, and waist circumference. This association was confirmed in backward multiple linear regression analysis (β=-0.38; p=0.009) adjusting for age, ethnicity, waist circumference and mean arterial pressure. In the elevated BP group, BRS associated with FH in single (r=-0.39; p=0.02), partial (r=-0.55; p=0.001) and backward multiple linear regression analysis (β=-0.54; p=0.001). No association between BRS and ACR was evident in the elevated BP group. Conclusion We observed a cardioprotective relationship between BRS and kidney function in boys with normal blood pressure. Whereas, in boys with elevated blood pressure, their predisposed FH related cardiovascular risk may be amplified by lower BRS. Name: Presenting Author Information Article Category Abstract Title Hypertension in Africa Research Team, MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom lisa.uys@nwu.ac.za English Abstract Researchers/Clinicians - Early, mid & senior career Baroreceptor sensitivity, kidney function and positive family history of cardiovascular and lifestyle risk in boys with normal and elevated blood pressure Author Affiliation: Email: Dr Lisa Uys Science Theme Population Authors Name & Surname Title Expertise Affiliation Email Country Lisa Uys Dr Cardiovascular Physiology Hypertension in Africa Research Team, MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom lisa.uys@nwu.ac.za South Africa Wayne Smith Prof Cardiovascular Physiology Hypertension in Africa Research Team, MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom wayne.smith@nwu.ac.za South Africa Carina Mels Prof Cardiovascular Physiology & Biochemistry Hypertension in Africa Research Team, MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom carina.mels@nwu.ac.za South Africa Annemarie Wentzel Dr Cardiovascular Physiology Hypertension in Africa Research Team, MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom annemarie.wentzel@nwu.ac.za South Africa
AFRICA Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 8 Submission ID: 1622 Introduction Nocturnal blood pressure is a predictor of cardiovascular disease irrespective of daytime blood pressure. The magnitude of nocturnal blood pressure can be altered by various factors including sleep duration. Sleep dysregulation (short and long sleep duration) may be evident in individuals with depressive symptoms and is associated with increased nocturnal blood pressure, however, data in young populations are scant. The aim of this study was to investigate whether associations exist between nocturnal blood pressure and sleep duration in young adults with and without depressive symptoms. Methods We included apparently healthy individuals with (N=257) and without (N=531) depressive symptoms aged 20-30 years. Participants were normotensive at screening (clinic blood pressure <140/90 mmHg). We determined nocturnal blood pressure from 24-hour ambulatory blood pressure monitoring while sleep duration was assessed using diary cards and Acti-heart data. Stratification of individuals with and without depressive symptoms were based on the assessment of depression severity with the 9-item Patient Health Questionnaire (none-to-minimal symptoms and moderate-to-severe symptoms, respectively). Results Sleep duration was higher in individuals with depressive symptoms compared to those without depressive symptoms (p=0.004). After multiple adjustments for covariates, an independent negative association (Adjusted R-squared=0.109; β=-0.19; p=0.002) was observed between nocturnal diastolic blood pressure and sleep duration in individuals with depressive symptoms only. Conclusion The negative association between nocturnal diastolic blood pressure and sleep duration may indicate that longer sleep duration may be play a protective role against the elevated nocturnal blood pressure in individuals with depressive symptoms. Name: Presenting Author Information Article Category Abstract Title North-West University Gontse.Mokwatsi@nwu.ac.za English Abstract Researchers/Clinicians - Early, mid & senior career Association between nocturnal blood pressure and sleep duration in individuals with and without depressive symptoms Author Affiliation: Email: Gontse Mokwatsi Science Theme Basic Author Name & Surname Title Expertise Affiliation Email Country Gontse Mokwatsi Dr Hypertension and blood pressure monitoring North-West University Gontse.Mokwatsi@nwu.ac.za South Africa ORAL PRESENTATION
Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 9 AFRICA Submission ID: 1624 Introduction Decline in kidney function has been associated with increased risk of adverse renal outcomes, cardiovascular disease, and mortality. There is limited data available on the trajectory of kidney function overtime and risk factors in African populations. We investigated the changes in kidney function over a period of 10-years and determined the factors associated with decline in kidney function in an African population. Methods We followed 719 individuals aged 30 years and above from year 2005 to 2015 residing in urban and rural areas of the North West province in South Africa. Kidney function was assessed using estimated glomerular filtration rate (eGFR) measured at baseline and at a 10-year follow-up. A decline in kidney function was defined as a drop of 25% or more in eGFR. The risk factors investigated included age, sex, locality, baseline eGFR, hypertension, diabetes, obesity, dyslipidaemia, HIV status, smoking and alcohol consumption. Demographic and lifestyle information was collected using questionnaires and laboratory tests were conducted to analyse biological samples. The prevalence of hypertension, diabetes, obesity and dyslipidaemia were determined according to respective guidelines. Logistic regression analysis was employed to identify significant risk factors associated with the decline in kidney function. Results Of the 719 participants, 10.4% experienced a >25% decline in kidney function over the study period and their baseline eGFR was 97.6 ml/ min/1.73m^2 which declined to 59.7 ml/min/1.73m^2 at follow-up. Among this group, 70% had hypertension, 15% had diabetes, 51% were obese, 37% were smokers, and 29% consumed alcohol. The identified primary risk factors associated with a decline in kidney function included age (OR: 3.32; 95% Cl: 2.29 – 4.82), baseline eGFR (OR: 1.96; 95% Cl: 1.28 – 2.99) and urban locality (OR: 2.40; 95% Cl: 1.37 – 4.20. Conclusion Age, baseline eGFR and urban locality are strong and independent predictors of decline in kidney function. In the absence of independent results with the traditional risk factors (hypertension, diabetes, obesity, smoking, alcohol consumption); it is recommended that future studies consider additional risk factors related to the location of the individuals in addition to the traditional risk factors for the prediction of kidney function decline. Regular estimation of eGFR from a young age would allow targeted and timely intervention necessary to reduce the burden of kidney disease. Name: Presenting Author Information Article Category Abstract Title Hypertension in Africa Research Team nonkululeko.navise@nwu.ac.za English Abstract Students - Currently enrolled postgraduate students Predictors of estimated glomerular filtration rate decline, over a 10-year period in a cohort in the North West province, South Africa Author Affiliation: Email: Nonkululeko Navise Science Theme Basic Authors Name & Surname Title Expertise Affiliation Email Country Nonkululeko Navise Ms Kidney function Hypertension in Africa Research Team nonkululeko.navise@nwu.ac.za South Africa Gonste Mokwatsi Dr Hypertension Hypertension in Africa Research Team; MRC Unit for Hypertension and Cardiovascular Disease gontse.mokwatsi@nwu.ac.za South Africa Leandi Lammertyn Prof Metabolic, cardiovascular and lifestyle markers Hypertension in Africa Research Team; MRC Unit for Hypertension and Cardiovascular Disease leandi.lammertyn@nwu.ac.za South Africa ORAL PRESENTATION
AFRICA Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 10 Submission ID: 1629 Introduction Impaired aortic function is a core mechanism in the development of uremic cardiomyopathy. We recently documented in a large cohort of chronic kidney disease (CKD) patients (n=743) that mean arterial pressure (MAP) can fully account for the potential impact of presumed hypertensive nephropathy (HNP) (103.9-115.7%) but not diabetic nephropathy (DNP), (-2.0%-(-)7.5%) on pulsatile pressures including peripheral pulse pressure (PP) and systolic blood pressure (SBP). This suggests that impaired aortic function may be improved by volume control and/or reducing systemic vascular resistance (SVR) in patients with HNP but not those with DNP. Herein, we address this hypothesis. Methods The current multi-ethnic study (black 40.0%; white 24.4%; mixed race 7.8%; Asian 27.8%) included 115 CKD patients (67 non-dialysis and 48 dialysis). Their mean (SD) age was 57.7 (14.0) years, 37.4% were women and CKD duration was 5.4 (4.5) years. HNP (53.9%), DNP (32.2%), glomerulonephritis (19.1%) and HIV associated nephropathy (7.8%) comprised the major CKD etiologies. Concurrent HNP and DNP was present in 31.1% of the patients. Aortic function measures comprised PP, SBP, central pulse pressure, central systolic blood pressure, proximal aortic stiffness as estimated by the inverse of total arterial compliance (invTAC), carotid-femoral pulse wave velocity, backward wave pressure and forward wave pressure. The potential mutually independent impact of presumed HNP and DNP on aortic function was assessed in confounder and mediator adjusted multiple regression models. The contribution of MAP and the interaction between cardiac output (CO) and SVR to CKD etiology-aortic function relationships was assessed in adjusted product of coefficient mediation analysis. The calculated power of the study was 0.997 based on α=0.05. Results Patients with compared to without concurrent HNP and DNP experienced more frequent cardiovascular disease (43.2% versus 14.9%, p=0.01) and impaired aortic function (p=0.006-0.05 for 5 of the measures). DNP was independently associated with each aortic function measure (p<0.001-0.02). HNP was not directly related to aortic function (p>0.05). Other covariates that were consistently associated with impaired aortic function measures except for invTAC, included MAP (p<0.001-0.01) and its determinants. MAP and CO x SVR did not account for the potential effect of DNP on any aortic function measure (0.02-(-)7.3%). Dialysis status did not impact any of the identified relationships (interaction p>0.05). Conclusion This study validates our previously reported findings. Our results suggest that reducing MAP by decreasing volume overload and/or SVR through fluid intake restriction, diuretic therapy and antihypertensive agents or vasodilators may improve aortic function in the overall CKD population. However, these interventions are unlikely to reverse impaired aortic function that is induced by DNP. The potential impact of MAP and its determinants as well as DNP on aortic function is similar in non-dialysis and dialysis patients. Whether increased arterial medial calcification associated with diabetes and DNP explain our findings merits further study. Name: Presenting Author Information Article Category Abstract Title Cardiovascular Pathophysiology and Genomics Research Unit, Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa. oluwatosin.tade@wits.ac.za English Abstract Researchers/Clinicians - Early, mid & senior career Diabetic nephropathy induced impaired aortic function is not mediated by mean arterial pressure and its determinants Author Affiliation: Email: Grace Tade Science Theme Clinical continued on next page ORAL PRESENTATION
Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 11 AFRICA Authors Name & Surname Title Expertise Affiliation Email Country Oluwatosin Grace Tade Dr Early career Wits University oluwatosin.tade@wits.ac.za South Africa Hon-Chun Hsu Dr Clinician Nephrology Unit, Milpark Hospital, Johannesburg, South Africa kengjulin@yahoo.com.au South Africa Chanel Robinson Dr Researcher Wits University chanelgr@gmail.com South Africa Angela J Woodiwiss Prof Senior Career Cardiovascular Pathophysiology and Genomics Research Unit, Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa Angela.woodiwiss@wits.ac.za South Africa Noluntu Dlongolo Ms Rheumatology Unit, Rosebank Hospital, Johannesburg, South Africa dlongolonhlanhla@gmail.com South Africa Gloria Teckie Dr Clinician Division of Nephrology, Department of Medicine, Chris Hani Baragwanath Hospital and Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa gteckie@hotmail.com South Africa Ahmed Solomon Prof Clinician Internal Medicine Department, University of the Witwatersrand, Johannesburg, South Africa ahmed.solomon@icloud.com South Africa Patrick H Dessein Prof Clinician Cardiovascular Pathophysiology and Genomics Research Unit, Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa,Rheumatology Unit, Rosebank Hospital, Johannesburg, South Africa,Internal Medicine Department, University of the Witwatersrand, Johannesburg, South Africa patrick.dessein22@gmail.com South Africa Submission ID: 1629 continued ORAL PRESENTATION
AFRICA Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 12 Submission ID: 1630 Introduction In various cardiovascular diseases the reduction of heart rate (HR) with β-blockers or other HR reducing agents is mandatory. However, decreases in HR are associated with increases in central aortic pulse pressure (PPc), which is concerning as increased central pressure pulsatility produces organ damage. However, whether the inverse relationship between HR and PPc is modified by either peripheral arterial blood pressure (BP) or aortic stiffness is unclear. Our aim was to determine, in an intervention study, the impact of arterial BP and aortic stiffness on the relationship between HR and PPc. Methods Patients with artificial cardiac pacemakers (n=16) were recruited from Life Flora Hospital in Roodepoort, Johannesburg between 2023 and 2024. Participants were paced in 10 bpm intervals in a range of 50-90 bpm. At each interval, central aortic BP was recorded using a SphygmoCor device and echocardiography was performed to assess aortic outflow tract diameter and flow velocity. Aortic characteristic impedance (aortic stiffness, Zc) was calculated from central aortic pressure and aortic flow using a standard formula. An average of 3 sets of measurements per participant (range of 2-4) was obtained, resulting in a total sample size of 48. To assess the impact of arterial BP, the study group was divided into those with systolic/diastolic BP below (n=20, low BP) versus above (n=28, high BP) 130/85mm Hg. To assess the impact of Zc, the study group was divided according to the median value of Zc (110dynes.s/cm5) (n=20 below [low Zc] and n=28 above [high Zc]). Multiple linear regression models adjusting for age, sex, body mass index and either peripheral arterial PP or mean arterial pressure (MAP) were used to determine the relationship between PPc and HR and the effects of peripheral arterial BP and aortic Zc on this relationship. Results Central aortic PP was inversely related to HR (r=-0.287, p<0.05), whereas peripheral arterial PP was not (r=-0.058, p=0.70). The PPc – HR relationship was independent of confounders including peripheral PP (partial r=-0.474, p<0.005) and MAP (partial r=-0.409, p<0.01). In patients with high BP, there was a strong PPc – HR relationship (partial r=-0.729, p<0.0005); whereas in patients with low BP, the relationship was weaker (partial r=-0.508, p=0.05). In patients with high Zc there was a strong PPc – HR relationship (partial r=-0.672, p<0.0005); whereas in patients with low Zc, the relationship was not significant (partial r=-0.293, p=0.27). Conclusion In an intervention study, we show that central aortic PP is inversely related to HR and that this relationship is modified by both peripheral arterial BP and aortic stiffness. These data suggest that in patients requiring HR reducing pharmacological agents, peripheral BP should be maintained at below 130/85 mm Hg in order to prevent organ damage associated with increased pulsatile loads. Furthermore, in conjunction with HR reducing agents, the use of pharmacological agents that reduce aortic stiffness, such as aldosterone receptor antagonists, is advisable. Name: Presenting Author Information Article Category Abstract Title University of Witwatersrand 2105607@students.wits.ac.za English Abstract Students - Currently enrolled postgraduate students Effects of Arterial Blood Pressure and Aortic Stiffness on the Inverse Relationship between Central Pulse Pressure and Heart Rate Author Affiliation: Email: Zak Coetzee Science Theme Basic Authors Name & Surname Title Expertise Affiliation Email Country Zak Coetzee Mr, Student University of Witwatersrand 2105607@students.wits.ac.za South Africa Vernice Peterson Dr. Cardiovascular Physiology University of Witwatersrand Vernice.Peterson@wits.ac.za South Africa Danelle Els Miss. Cardiovascular Physiology University of Witwatersrand nellyels14@gmail.com South Africa Ferande Peters Prof. Cardiologist University of Witwatersrand ferande.peters@gmail.com South Africa Angela Woodiwiss Prof. Cardiovascular Physiology University of Witwatersrand angela.woodiwiss@wits.ac.za South Africa ORAL PRESENTATION
Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 13 AFRICA Submission ID: 1631 Introduction In patients with systolic heart failure (HF), both decreases and increases in pulse pressure (PP) are associated with poor prognosis. If aortic PP in systolic HF is decreased due to systolic dysfunction, then improvements in stroke volume (SV) or forward wave pressure (Pf) would be beneficial. Alternatively, if hypertension is the primary cause of systolic HF, aortic PP may be increased due to high aortic characteristic impedance (Zc) and backward wave pressure (Pb), which would be detrimental. I aimed to compare central aortic hemodynamics, and the impact of BP control, between stable systolic HF patients and community participants. Methods Consecutive consenting adult patients diagnosed with HF of systolic origin (n=42), were randomly recruited from the hypertension clinic at Life Flora Hospital, Johannesburg. Central aortic pressure (SphygmoCor) and aortic outflow tract diameter and flow velocity (echocardiography) were acquired for each patient. The aortic pressure waves were coupled with the aortic flow waves, and wave separation analysis was performed to obtain the various determinants of PPc (backward wave pressure [Pb], forward wave pressure [Pf], reflected pressure, rereflected pressure, aortic flow [Q], aortic characteristic impedance [Zc], the pressure generated by the product of flow and characteristic impedance [QxZc]). Stroke volume (SV) and systemic vascular resistance (SVR) were calculated using standard formulae. The data collected from the 42 stable HF patients, was compared to data collected in 298 age- and sex-matched participants from a community-based study, adjusting for potential confounders that may differ between these two groups. The impact of BP control (SBP/DBP<140/90mmHg), and more intense BP control (SBP/DBP<30/80 mm Hg), on comparisons of haemodynamic variables between patients with systolic HF and community participants, was assessed using multivariate-adjusted ANOVA. Results Systolic HF patients had lower central PP and Pb (p<0.005) and higher HR (p<0.005) than community participants. No other differences were noted. Systolic HF patients with uncontrolled BP (SBP/DBP≥140/90mmHg) had higher Zc (p<0.005), Pf (p<0.05), and SVR (p<0.05) than both HF patients and community participants with controlled BP. Despite similar peripheral and central PP to community participants with uncontrolled BP, Zc (p<0.005) and SVR (p<0.05) were higher in HF patients with uncontrolled BP. However, when assessing more intense BP control (SBP/DBP<130/80mmHg), the differences in Zc, QxZc, and SVR between the HF patients and community participants with uncontrolled BP were eliminated. Conclusion A lower central aortic PP, which was not due to decreased SV, was observed in stable systolic HF patients. However, in the presence of uncontrolled BP (SBP/DBP≥140/90mmHg), but not intense BP control (SBP/DBP<130/80mmHg), Zc, QxZc and SVR were increased in patients with systolic HF. Hence, BP control and its level of control are imperative in patients with systolic HF to protect the heart from the detrimental effects of increased afterloads. Name: Presenting Author Information Article Category Abstract Title Marcus N Lebelo, Vernice R Peterson, Danelle Els, Jamie-Leigh Kinsey, Ferande Peters, Angela J Woodiwiss. 1607905@students.wits.ac.za English Abstract Students - Currently enrolled postgraduate students Comparison of Aortic Haemodynamics in Community Participants and Patients with Systolic Heart Failure and the Impact of Blood Pressure Control. Author Affiliation: Email: Marcus N Lebelo Science Theme Clinical Author Name & Surname Title Expertise Affiliation Email Country Marcus Lebelo Mr CPGRU 1607905@students.wits.ac.za South Africa ORAL PRESENTATION
AFRICA Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 14 Submission ID: 1633 Introduction Childhood-onset hypertension which tracks into adulthood is on the rise globally. Identifying the risk factors for primary hypertension in children remain epidemiologically relevant to develop early intervention and prevention strategies that will mitigate premature hypertension onset. This study explored the changes in blood pressure in South African children over a four-year period and tested the predictive value of individual and composite baseline risk factors for elevated blood pressure. Methods We included 767 healthy Black and White children with both baseline (mean age = 7 years) and follow-up (mean age = 11 years) data. Office blood pressure, anthropometry, cardiorespiratory fitness, health-related quality of life, food intake and urinary biomarkers were measured. Children were stratified into groups according to blood pressure status as determined by the 2017 American Academy of Pediatrics clinical practice guidelines. Individual baseline risk factors and composite risk factor patterns (obtained by exploratory factor analyses) were used to predict follow-up blood pressure status using Cox-proportional hazard ratios. Results The prevalence of elevated blood pressure increased by 5% over four-years. High-intensity physical activity (OR: 1.69; p= 0.024) and higher BMI-z score (OR: 2.68; p<0.001) cross-sectionally increased the odds of having baseline elevated blood pressure. Additionally, White ethnicity (HR: 2.00; p=0.028), higher BMI-z score (HR: 1.44; p=0.044), higher sugar-sweetened beverage intake (HR: 1.90; p=0.003), lower socioeconomic status (HR: 0.56; p=0.022), lower heart rate (HR: 0.72; p=0.041) and lower health-related quality of life (HR: 0.64; p=0.006) longitudinally predicted elevated blood pressure over four-years. No significant results were observed with composite risk factor patterns in cross-sectional or prospective analyses compared to individual risk factors. Conclusion Early intervention, focussing on individual, rather than composite, modifiable and non-modifiable risk factors, may reduce early-onset hypertension in childhood and the subsequent burden of cardiovascular disease in the global ageing population. Name: Presenting Author Information Article Category Abstract Title Hypertension in Africa Research Team cvolschenk50@gmail.com English Abstract Students - Currently enrolled postgraduate students A prospective analysis to assess the multifactorial risk of childhood-onset hypertension: The ExAMIN Youth SA study Author Affiliation: Email: Chanelle Volschenk Science Theme Basic Authors Name & Surname Title Expertise Affiliation Email Country Chanelle Volschenk Miss Cardiovascular Physiology Hypertension in Africa Research Team cvolschenk50@gmail.com South Africa Ruan Kruger Prof Paediatric hypertension Hypertension in Africa Research Team; South African Medical Research Council Extramural Unit for Cardiovascular Disease ruan.kruger@nwu.ac.za South Africa Esme Jansen van Vuren Dr Cardiovascular physiology and biological psychiatry Hypertension in Africa Research Team; South African Medical Research Council Extramural Unit for Cardiovascular Disease esme.jansenvanvuren@nwu.ac.za South Africa Annemarie Wentzel Dr Neurocardiology and cardiometabolic stress reactivity Hypertension in Africa Research Team; South African Medical Research Council Extramural Unit for Cardiovascular Disease annemarie.wentzel@nwu.ac.za South Africa ORAL PRESENTATION
Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 15 AFRICA Submission ID: 1634 Introduction Heart rate-reducing agents such as β-blockers and ivabradine (IVB) are frequently used in the management of patients with cardiovascular disease. However, reductions in heart rate (HR) are associated with increases in central aortic pulse pressure (PPc), but not peripheral PP. The inverse HR-PPc relationship, and the mechanisms thereof, have been identified primarily in cross-sectional studies. Hence, intervention studies are required to establish causality and the primary mechanisms. The aim of my intervention study in rats, was to assess the effect of changes in HR on PPc, and the impact of the determinants of PPc on the HR-PPc relationship. Methods Male spontaneously hypertensive rats (SHR) (n=15) and Wistar Kyoto (WKY) normotensive rats (n=12), at 17 months of age, were studied. To induce changes in blood pressure (BP) and HR, approximately 7 doses of a vasoconstrictor, phenylephrine (PE) (0.5 mg/kg per dose), followed by about 6 doses of IVB (0.5 mg/kg per dose) were administered to anaesthetised rats. Central aortic pressures (carotid catheter and high-resolution pressure transducer paired with PowerLab Lab Chart 8 system) and aortic outflow tract diameter and flow velocity (echocardiography) were systematically acquired for each anaesthetised rat at baseline and then during the administration of PE and then IVB. The aortic pressure waves were coupled with the aortic flow waves, and wave separation analysis performed to obtain the various determinants of PPc (backward wave pressure [Pb], forward wave pressure [Pf], reflected pressure, re-reflected pressure, aortic flow [Q], aortic characteristic impedance [Zc], the pressure generated by the product of flow and characteristic impedance [QxZc]), using standard formulae. Bivariate and multivariate correlation analyses were performed to determine the relationship between HR and PPc, and the impact of determinants of PPc on this relationship respectively. Results Heart rate was inversely associated with PPc (p<0.0001), backward wave pressure (Pb) (p<0.0001), forward wave pressure (Pf) (p<0.0001), reflected pressure (p<0.0001), and re-reflected pressure (p<0.0001). On the contrary, aortic flow (Q), aortic characteristic impedance (Zc), and the pressure generated by the product of flow and characteristic impedance (QxZc) were not related to heart rate. The slope of the relationship between HR and PPc was diminished by adjustments for Pf, and markedly diminished by adjustments for Pb, reflected pressure, or re-reflected pressure (p<0.05 to p<0.0001). Conclusion In an intervention study in rats, we confirm the inverse relationship between HR and PPc, and show that wave reflection and re-reflection are the primary mechanisms responsible for the HR-PPc relationship. These data suggest that in individuals who require HR-reducing agents, wave-reflection and re-reflection should be targeted, such as by intensive lowering of BP. Name: Presenting Author Information Article Category Abstract Title University of the Witwatersrand 1474838@students.wits.ac.za English Abstract Students - Currently enrolled postgraduate students Impact of determinants of aortic pulse pressure on the relationship between heart rate and aortic pulse pressure: an intervention study in rats Author Affiliation: Email: Katleho Khanye Science Theme Basic Authors Name & Surname Title Expertise Affiliation Email Country Katleho Khanye Mr Physiology University of the Witwatersrand 1474838@students.wits.ac.za South Africa Angela Woodiwiss Professor Physiology University of the Witwatersrand angela.woodiwiss@wits.ac.za South Africa Vernice Peterson Dr Physiology University of the Witwatersrand vernice.peterson@wits.ac.za South Africa Nonhlanhla Mthembu Dr Physiology University of the Witwatersrand nonhlanhla.mthembu@yahoo.com South Africa ORAL PRESENTATION
AFRICA Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 16 Submission ID: 1636 Introduction The surge of cardiovascular disease across Sub-Saharan Africa is driven largely by hypertension and other cardiometabolic risk factors. South Africa, like other low-middle-income countries, faces a disproportionate burden due to the increasing prevalence of hypertension, exacerbated by low awareness, treatment, and control rates. The emergence of treatment-resistant hypertension (TRH) characterised by blood pressure above target levels despite use of three or more antihypertensive medications at maximally tolerated doses, or on four or more agents regardless of blood pressure control status -presents significant challenges to this goal. An increased risk of major adverse cardiovascular events, hypertensive-mediated organ damage, and increased healthcare costs are associated with this hypertension phenotype. Despite these serious implications, the impact of TRH in the South African context remains underexplored. Methods An observational analytical study was conducted at the chronic outpatient clinic at Wentworth Hospital, a district hospital in KwaZuluNatal, South Africa, between March and April 2024. Our objective was to determine the prevalence, predictors, and profiles of TRH in a primary care setting among people living with hypertension (PLWH). We analysed demographic, clinical, and biochemical parameters of 400 systematically randomised essential hypertensive patients aged over 30. Participants underwent office blood pressure (BP) monitoring and completed an interviewer-administered questionnaire that assessed medication adherence, and risk score assessments. A chart review was conducted to assess clinical parameters and the antihypertensive drug profile. Determinants of apparent TRH were identified using a multivariate logistic regression model. Results The mean age of the sample was 64.42 years (SD = 10.75), with a female preponderance of 65% (n = 260), and two-thirds comprised of Black Africans (35.3%) and Indians (30.5%). Most of the PLWH were obese, with a median body mass index of 30.24 kg/m² (IQR = 8.2). The prevalence of apparent TRH was 18.8% (n = 75) among treated hypertensives, with uncontrolled TRH accounting for 11% (n = 44) and controlled TRH for 7.8% (n = 31). Compared with their non-resistant counterparts, multivariable analysis revealed that waist circumference (odds ratio [OR] = 1.04, p = <0.001), electrocardiographic left ventricular hypertrophy (OR = 5.06, p = 0.005), chronic kidney disease (OR = 2.70, p = 0.002), dyslipidaemia (OR = 2.51, p = 0.035), and a high obstructive sleep apnoea (OSA) risk score (OR = 2.16, p = 0.004) were predictive of apparent TRH. Mineralocorticoid receptor antagonists were an underused antihypertensive drug class overall, accounting for 10.8% (n = 43). Conclusion Hypertension control in Africa remains a critical priority, particularly in a healthcare setting burdened with multiple challenges. Notably, this study is the first to describe the prevalence of apparent TRH in a general hypertensive population in primary care in South Africa. These insights are particularly valuable for enhancing hypertensive management and updating guidelines locally, especially regarding the utility of cost-effective anthropometric and OSA screening measures to identify at-risk patients for further care escalation. Our findings reveal a complex interplay between cardiometabolic conditions and TRH, underscoring the need for multifaceted interventions to prevent cardiovascular events in this high-risk subgroup of PLWH. Name: Presenting Author Information Article Category Abstract Title University of Kwa-Zulu Natal, College of Health sciences kellygov2@gmail.com English Abstract Researchers/Clinicians - Early, mid & senior career Prevalence and predictors of apparent treatment-resistant hypertension among patients in primary care in South Africa: a single-centre observational study Author Affiliation: Email: Kellicia Courtney Govender Science Theme Clinical Authors Name & Surname Title Expertise Affiliation Email Country Kellicia C. Govender Dr General medicine University of Kwa-Zulu Natal, College of Health sciences kellygov2@gmail.com South Africa Mergan Naidoo Prof Family medicine University of Kwa-Zulu Natal, College of Health sciences South Africa ORAL PRESENTATION
Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 17 AFRICA Submission ID: 1644 Introduction Between euglycemia and diabetes is an area of prediabetes which includes impaired glucose tolerance and impaired fasting glucose. These entities, despite associated adverse outcomes, are often undiagnosed and unmanaged. Several tests are now well established for the diagnosis of pre-diabetes and diabetes. These include the fasting glucose, two-hour oral glucose tolerance test and glycosylated haemoglobin. Whilst recent literature has shown a high frequency of undiagnosed abnormal glucose metabolism in patients presenting with acute coronary syndromes, it remains unknown which of these modalities is the most sensitive in diagnosing a chronic state of dysglycemia in the acute setting. Methods This was a retrospective analysis of patients admitted to the R K Khan Hospital Coronary Care Unit between January 2006 to December 2011. Of the 2829 patients that were screened, 1933 were excluded, with only 896 eligible. All patients had a confirmed acute myocardial infarction and were not known to have diabetes mellitus. Patient with impaired renal function and known hemoglobinopathies were also excluded. A fasting plasma glucose and glycosylated haemoglobin was performed the morning after admission and an oral glucose tolerance test was conducted on day 4 of their hospital stay. Utilising the results from the above tests, patients were then classified via their glycemic profile as either euglycemic, pre diabetic or with overt diabetes mellitus. Data were analysed using Stata 14. Box-plots were utilised to provide graphical summaries of the percentile distribution of the blood glucose measurements. Association between categorical variables was assessed using the Pearson chi-square (χ2) test. Scatter plots were employed for pairwise comparison of FPG, 2hr OGTT and HbA1c. We estimated the likely true prevalence of diabetes by assuming an imperfect Gold Standard. The predictive performance of each measure against the latent diabetes outcomes was assessed using sensitivities and specificities, positive and negative predictive values. Results The study population comprised of 896 individuals, 80.58% of which presented with a STEMI. The majority of were males (70%), with an average age of 56.7 years. Most of the patients were Indian Asian (91.07%). Euglycemia occured in 65.29%, 33.48% and 20.76% of the patients by means of a fasting plasma glucose, 2 hour oral glucose tolerance test and HbA1C respectively. Utilising the fasting plasma glucose, we diagnosed 21.32% with impaired fasting glucose and 13.39% with diabetes. With the OGTT, 39.84% had impaired glucose tolerance and 26.67% diabetes. The HbA1C diagnosed 47.66% with pre diabetes and 31.58% with diabetes. Conclusion The results of our study show that of the 896 individuals admitted to the R K Khan Hospital CCU with an acute myocardial infarction, the majority have some form of abnormal glucose regulation. The prevalence of abnormal glucose regulation appears to be related to the diagnostic test utilised. Via the fasting plasma glucose almost two thirds of patients were euglycemic. However, 66.51% and 79.24 % of patients had either pre diabetes or overt diabetes mellitus using the OGTT and HbA1c respectively. It is therefore our recommendation that all patients with an acute myocardial infarction have both an admission HbA1c and pre-discharge OGTT. Name: Presenting Author Information Article Category Abstract Title UKZN drrllutchman@yahoo.com English Abstract Researchers/Clinicians - Early, mid & senior career The prevalence of undiagnosed impaired glucose regulation in patient presenting with an acute myocardial infarction Author Affiliation: Email: Dr Rohan Lutchman Science Theme Clinical Authors Name & Surname Title Expertise Affiliation Email Country Rohan Lutchman Dr Cardiologist UKZN drrllutchman@yahoo.com South Africa Naresh Ranjith Prof Cardiologist UKZN ranjith@lantic.co.za South Africa Benn Sartorius Prof Statistics University of Queensland b.sartorius@uq.edu.au Australia ORAL PRESENTATION
AFRICA Cardiovascular Journal of Africa • SAHS Biennial Congress 2024 18 Submission ID: 1645 Introduction Chronic kidney disease (CKD) is a multifactorial progressive condition that has a strikingly adverse impact on cardiovascular disease risk. The identification of CKD specific effects on the cardiovascular system is compounded by common comorbidities such as hypertension, diabetes, and cardiovascular disease. This complexity necessitates the development of animal models that can determine the distinct pathophysiological mechanisms of CKD and its cardiovascular impacts. The present study was designed to delineate the distinct cardiovascular outcomes associated with CKD only versus CKD with concurrent hypertension. We aimed to induce CKD in Wistar Kyoto rats (WKYs), representing a model of lone CKD, and Spontaneously Hypertensive Rats (SHRs), representing a model of CKD with comorbid hypertension. Methods Both WKY and SHR were divided into control and adenine-treated subgroups. The adenine treated groups were given adenine supplemented diet for 8 weeks. Prior to terminations, animals were placed in metabolic cages for 8 hours to collect urine. On the day of terminations, under anaesthesia, a catheter was inserted into the carotid artery to measure central pressures and echocardiography was performed to assess cardiac function. Pulsepenlab was used to determine aortic function. Blood samples were collected via cardiac puncture. Thereafter, the heart and kidneys were harvested and weighed. Results The urea concentration was larger in SHR-treated rats compared to those in other groups (P= 0.028) Central systolic blood pressure (P<0.001), pulse pressure (P<0.02) and mean arterial pressure (P<0.001) were larger in SHR and SHR-treated groups compared to the WKY and WKY-treated groups. The SHR-treated group had a larger pulse pressure compared the WKY-treated group (P<0.001). Forward wave pressure (P<002), augmentation index (P=006) and augmented pressure (P=0.004) were increased in SHR-treated compared to WKY and WKY-treated groups. Left ventricular mass adjusted to body weight was higher in the SHR treated (P=0.02) compared to other groups. Right kidney mass adjusted for body weight was larger in the SHR-treated group than in the SHR (P = 0.0004) and WKY control groups (P = 0.002). The WKY-treated group also had heavier right sided kidneys than the WKY control group. Left kidney mass adjusted for body weight was larger in the SHR-treated group than in the WKY (P = 0.0002) and the SHR control groups (P = 0.006). Conclusion SHRs experience a greater susceptibility to adenine-induced kidney impairment than WKYs. Adenine-induced kidney impairment causes more impaired aortic function, left ventricular mass and kidney weight in SHRs than in WKYs. The current study design can allow for determining the differential impact of lone CKD versus CKD with comorbid hypertension on cardiovascular function and structure. Name: Presenting Author Information Article Category Abstract Title University of the Witwatersrand, Johannesburg South Africa oluwatosin.tade@wits.ac.za English Abstract Researchers/Clinicians - Early, mid & senior career Differential Responses to Adenine-Induced Chronic Kidney Disease in WKY and SHR Models Author Affiliation: Email: Grace Tade Science Theme Basic Authors Name & Surname Title Expertise Affiliation Email Country Oluwatosin Grace Tade Dr Early career Wits University oluwatosin.tade@wits.ac.za South Africa Makabongwe Mazibuko Ms Student Wits University 1353904@students.wits.ac.za South Africa Maud Dzikunu Ms Student Wits University 1813250@students.wits.ac.za South Africa Ursula Mariani Ms Student Wits University ursula.mariana@wits.ac.za South Africa Patience Mahema Ms Student Wits University 1432522@students.wits.ac.za South Africa Nonhlanhla Mthembu Dr Researcher Wits University nonhlanhla.mthembu@wits.ac.za South Africa Vernice Peterson Dr Researcher Wits University vernice.peterson@wits.ac.za South Africa Angela Woodiwiss Prof Senior Academic and researcher Wits University angela.woodiwiss@wits.ac.za South Africa Patrick Dessein Prof Clinician and researcher Wits University patrick.dessein22@gmail.com South Africa ORAL PRESENTATION
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