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AFRICA
Cardiovascular Journal of Africa • ABSTRACTS – SA HEART
®
CONGRESS 2019
S22
Cardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension
Pheletso Letuka
University of Cape Town, Rondebosch, South Africa
Introduction:
Patients with resistant hypertension, who never achieve blood pressure (BP) control despite maximal medical treatment, represent a
distinctive phenotype which differs from the extensive proportion of patients whose BP can be controlled. Our aim is to identify patients with resistant
uncontrolled hypertension and to compare their phenotype to resistant controlled hypertensives and healthy controls.
Methods:
Fifty patients were enrolled from the Groote Schuur Hospital Hypertension Clinic: 30 with resistant uncontrolled hypertension, the other
20 with resistant controlled hypertension. Twelve age- and sex-matched healthy controls were enrolled. Assessments included clinical examination,
electrocardiography, echocardiography, applanation tonometry, serum biomarkers and cardiovascular magnetic resonance (CMR).
Results:
Patients with RHTN had significantly higher systolic (155.6 ± 21.6mmHg, p<0.0001), diastolic (88.4 ± 14.5mmHg, p=0.03) BP, mean arterial BP (115.4 ±
17.2mmHg, p=0.004) and pulse pressure (67.3 ± 14.2mmHg, p=0.001). Furthermore, they had significantly lower small artery elasticity (4.1 ± 2.1 vs. 6.9 ± 3.6 vs.
3.3 ± 1.3ml/mmHgx100, p<0.0001) and higher systemic vascular resistance (1 754 ± 418.4 vs. 1 363 ± 371.5 vs. 1 907 ± 474dyneXsecXcm-5, p=0.002). On CMR,
both patient groups had lower left ventricular (LV) end-systolic volumes (p=0.02), higher LV stroke volume (p=0.006) and LV ejection fraction (p<0.0001). Both
groups of patients had higher right ventricular ejection fraction (p<0.0001).
Conclusion:
In summary, patients with resistant uncontrolled hypertension are more likely to suffer target end organ damage as a result of vascular and
concentric remodelling.
Adherence to secondary prophylaxis for rheumatic fever with Benzathine penicillin: Pilot programme in Maputo, Mozambique
Edna Lichucha and Ana Olga Mocumbi
Instituto Nacional De Saúde, Marracuene District, Mozambique
Introduction:
Rheumatic heart disease (RHD) is the result of an immune process resulting from Group A Beta-haemolytic streptococcal infection. It is a
public health problem in Mozambique, given the high prevalence in school populations with the first indication for cardiovascular surgery due to acquired
disease. In the absence of a surveillance system for RHD, we performed a prospective observational study and we implemented a pilot prevention and
control programme to assess adherence to secondary prophylaxis using Benzathine penicillin G (BPG).
Methods:
We conducted the study from November 2017 - October 2018 at Maputo Central Hospital. The BPG injection sessions are held twice a week,
Tuesdays and Thursdays, at the Cardiology Unit. Standardised data were collected from each patient regarding socio-demographic characteristics, place of
residence, clinical history and events related to BPG-injection. Descriptive statistics were used to analyse data.
Results:
We recruited 105 patients, 70 (66.67%) were female; mean age 20, SD 6 years. Thirteen participants (12.4%) were children aged 8 - 12 years and 38
(36.2%) were adolescents. The majority of the participants 67 (63.8%) were students. We administered 1 139 doses of BPG, of which 864 (75.85%) were on
schedule. For 134 (11.76%) doses, patients were out of schedule for more than 5 days, and for 141 (12.38%) there was up to 5 days delay. Two deaths (2/1 139
injections) occurred during BPG-injection, both in adolescents with severe disease in whom no classic signs of anaphylaxis occurred. Adherence to BPG was
76%, not reaching the 80% considered acceptable by the WHO; it did not vary over the year. The longest distance participants travelled from home to the
hospital was 15.8km and 14 (13.3%) participants who were not adherent, resorted to this group.
Conclusions:
Adherence to secondary prophylaxis with BPG was low. A need exists to better understand the underlying reasons for deaths
related to BPG.
Predictors of 1-year survival in South African transcatheter aortic valve implant candidates
Jacques Liebenberg, Hellmuth Weich and Anton Doubell
Division of Cardiology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University and Tygerberg Hospital, Bellville,
South Africa.
Introduction:
Transcatheter aortic valve implant (TAVI) is undergoing rapid expansion internationally. In lieu of local resource constraints, a major challenge
in applying this technology is the identification of patients most likely to benefit. The development of risk prediction models has proven elusive with reported
area-under-the-curve (AUC) of 0.6 - 0.65. The available models were developed in a first world setting and may not be applicable to South Africa. The purpose
of this study is to evaluate unique South African parameters in TAVI outcome prediction.
Methods:
Our experience and VARC defined outcomes with 244 successive TAVI implants were previously reported. This cohort was now used to evaluate
preprocedural variables for their impact on 1-year survival using univariate and multivariate models.
Results:
Factors found not to correlate with outcome included: age, renal function, aortic valve gradients as well as the commonly used surgical risk
prediction models – the STS and Euro SCORE. Factors best associated with 1-year survival were: left ventricular end-diastolic dimension (LVED) (mm), body
mass index (BMI) (kg/m
2
) and ejection fraction (EF)(%) (favouring smaller LVED and higher EF and BMI), absence of atrial fibrillation (AF), as well as 3 novel
parameters: independent living, ability to drive a car and independent food acquisition/cooking. Discriminant analysis of these factors yielded an AUC of 0.8
(CI 0.7 - 0.9) to predict 1-year survival with resubstitution sensitivities and specificities of 72% and 71% respectively.
Conclusion:
Apart from existing predictors, we identified 3 novel risk predictors (independent living, ability to drive a car, and independent food acquisition/
cooking) for 1-year survival. In this early evaluation, these parameters performed well with an AUC higher than the parameters used in many international
studies. The parameters are inexpensive and easily obtained at the initial patient visit. If externally validated, they may be valuable in assessing prospective
South African TAVI candidates.