Cardiovascular Disease in Sub-Saharan Africa

In silico Mechanics of Stem Cells Intramyocardially Transplanted with a Biomaterial Injectate for Treatment of Myocardial Infarction

PURPOSE

Biomaterial and stem cell delivery are promising approaches to treating myocardial infarction. However, the mechanical and biochemical mechanisms underlying the therapeutic benefits require further clarification. This study aimed to assess the deformation of stem cells injected with the biomaterial into the infarcted heart.

METHODS

A microstructural finite element model of a mid-wall infarcted myocardial region was developed from ex vivo microcomputed tomography data of a rat heart with left ventricular infarct and intramyocardial biomaterial injectate. Nine cells were numerically seeded in the injectate of the microstructural model. The microstructural and a previously developed biventricular finite element model of the same rat heart were used to quantify the deformation of the cells during a cardiac cycle for a biomaterial elastic modulus (Einj) ranging between 4.1 and 405,900 kPa.

RESULTS

The transplanted cells' deformation was largest for Einj = 7.4 kPa, matching that of the cells, and decreased for an increase and decrease in Einj. The cell deformation was more sensitive to Einj changes for softer (Einj ≤ 738 kPa) than stiffer biomaterials.

CONCLUSIONS

Combining the microstructural and biventricular finite element models enables quantifying micromechanics of transplanted cells in the heart. The approach offers a broader scope for in silico investigations of biomaterial and cell therapies for myocardial infarction and other cardiac pathologies.

Effect of biomaterial stiffness on cardiac mechanics in a biventricular infarcted rat heart model with microstructural representation of in situ intramyocardial injectate

Intramyocardial delivery of biomaterials is a promising concept for treating myocardial infarction. The delivered biomaterial provides mechanical support and attenuates wall thinning and elevated wall stress in the infarct region. This study aimed at developing a biventricular finite element model of an infarcted rat heart with a microstructural representation of an in situ biomaterial injectate, and a parametric investigation of the effect of the injectate stiffness on the cardiac mechanics. A three-dimensional subject-specific biventricular finite element model of a rat heart with left ventricular infarct and microstructurally dispersed biomaterial delivered 1 week after infarct induction was developed from ex vivo microcomputed tomography data. The volumetric mesh density varied between 303 mm-3 in the myocardium and 3852 mm-3 in the injectate region due to the microstructural intramyocardial dispersion. Parametric simulations were conducted with the injectate's elastic modulus varying from 4.1 to 405,900 kPa, and myocardial and injectate strains were recorded. With increasing injectate stiffness, the end-diastolic median myocardial fibre and cross-fibre strain decreased in magnitude from 3.6% to 1.1% and from -6.0% to -2.9%, respectively. At end-systole, the myocardial fibre and cross-fibre strain decreased in magnitude from -20.4% to -11.8% and from 6.5% to 4.6%, respectively. In the injectate, the maximum and minimum principal strains decreased in magnitude from 5.4% to 0.001% and from -5.4% to -0.001%, respectively, at end-diastole and from 38.5% to 0.06% and from -39.0% to -0.06%, respectively, at end-systole. With the microstructural injectate geometry, the developed subject-specific cardiac finite element model offers potential for extension to cellular injectates and in silico studies of mechanotransduction and therapeutic signalling in the infarcted heart with an infarct animal model extensively used in preclinical research.

Prevalence and incidence of hypertension in a heavily treatment-experienced cohort of people living with HIV in Uganda

INTRODUCTION

The effect of long-term exposure to antiretroviral therapy (ART) on hypertension in sub-Saharan Africa remains unclear. We aimed to determine the prevalence and incidence of hypertension in people living with HIV (PLWH) with more than 10 years of ART in Uganda.

METHODS

The analysis was performed within a cohort of adult PLWH with more than 10 years of ART at an HIV clinic in Kampala, Uganda. Participants were eligible for this analysis if they had ≥2 follow-up visits. Hypertension was defined as two consecutive systolic blood pressure (SBP) measures greater than 140 mmHg and/or diastolic blood pressure (DBP) greater than 90 mmHg, and/or documented diagnosis and/or the initiation of antihypertensives. We determined the proportion of PLWH with hypertension at baseline and used multivariable logistic regression to determine the factors associated with prevalent hypertension. To determine the incidence of hypertension, follow-up began from the cohort baseline date and was censored at the last clinic visit or date of the event, whichever occurred earlier. Multivariable Poisson regression was used to determine the adjusted incidence rate ratios (aIRR) of hypertension according to demographic, ART, and clinical characteristics.

RESULTS

Of the 1000 ALT participants, 970 (97%) had ≥2 follow-up visits, and 237 (24.4%) had hypertension at baseline. The odds of prevalent hypertension were 1.18 for every 5-year increase in age (adjusted odds ratio (aOR) 1.18, 95% CI 1.10-1.34) and were higher among males (aOR 1.70, 95% CI 1.20-2.34), participants with diabetes mellitus (aOR 2.37, 95% CI 1.10-4.01), obesity (aOR 1.99, 95% CI 1.08-3.60), high cholesterol (aOR 1.47, 95% CI 1.16-2.01), and those with prior exposure to stavudine (aOR 2.10, 95% CI 1.35-3.52), or nevirapine (aOR 1.90, 95% CI 1.25-3.01). Of the 733 participants without hypertension at baseline, 116 (15.83%) developed hypertension during 4671.3 person-years of follow-up (incidence rate 24.8 per 1000 person-years; 95% CI 20.7-29.8). The factors associated with incident hypertension were obesity (adjusted incidence rate ratio (aIRR) 1.80, 95% CI 1.40-2.81), older age (aIRR 1.12 per 5-year increase in age, 95% CI 1.10,1.25), and renal insufficiency (aIRR1.80, 95% CI 1.40-2.81).

CONCLUSION

The prevalence and incidence of hypertension were high in this heavily treated PLWH cohort. Therefore, with increasing ART coverage, HIV programs in SSA should strengthen the screening for hypertension in heavily treated PLWH.

Burden of out-of-pocket payments among patients with cardiovascular disease in public and private hospitals in Ibadan, South West, Nigeria: a cross-sectional study

OBJECTIVE

Given that the mechanism for financial protection is underdeveloped in Nigeria, out-of-pocket (OOP) payment for treating cardiovascular disease could impose substantial financial burden on individuals and their families. This study estimated the burden of OOP expenditures incurred by a cohort of patients with cardiovascular disease (CVD) in Ibadan, Nigeria.

DESIGN AND SETTINGS

This study used a descriptive cross-sectional study design. A standardised survey questionnaire originally developed by Initiative for Cardiovascular Health Research in Developing Countries was used to electronically collect data from all the 744 patients with CVD who accessed healthcare between 4 November 2019 and 31 January 2020 in the cardiology departments of private and public hospitals in Ibadan, Nigeria. Baseline characteristics of respondents were presented using percentages and proportions. The OOP payments were reported as means±SDs. Costs/OOP payments were in Nigerian Naira (NGN). The average US dollar to NGN at the time of data collection was ₦362.12 per $1. All quantitative data were analysed using STATA V.15.

OUTCOME MEASURES

The burden of outpatient, inpatient and rehabilitative care OOP payments.

RESULTS

Majority of the patients with CVD were within the age range of 45-74 years and 68.55% of them were women. The diagnostic conditions reported among patients with CVD were hypertensive heart failure (84.01%), dilated cardiomyopathy (4.44%), ischaemic heart disease (3.9%) and anaemic heart failure (2.15%). Across all the hospital facilities, the annual direct and indirect outpatient costs were ₦421 595.7±₦855 962.0 ($1164.2±$2363.8) and ₦19 146.5±₦53 610.1 ($52.87±$148.05). Similarly, the average direct and indirect OOP payments per hospitalisation across all facilities were ₦182 302.4±₦249 090.4 ($503.43±$687.87) and ₦14 700.8±₦ 69 297.1 ($40.60±$191.37), respectively. The average rehabilitative cost after discharge from index hospitalisation was ₦30 012.0 ($82.88).

CONCLUSION

The burden of OOP payment among patients with CVD is enormous. There is a need to increase efforts to achieve universal health coverage in Nigeria.

Patterns and outcomes of admissions to the medical acute care unit of a tertiary teaching hospital in South Africa

BACKGROUND

A Medical Acute Care Unit (MACU) was established at Chris Hani Baragwanath Academic Hospital (CHBAH) to provide comprehensive medical specialist care to the patients presenting with acute medical emergencies. Improved healthcare delivery systems at the MACU may result in shorter hospital stays, better outcomes, and less mortality.

OBJECTIVES

The study's objective was to describe the demographics, diagnoses, disease patterns, and outcomes, including patient's mortality, admitted to the MACU at CHBAH.

METHODS

Records of 200 patients admitted, between March 2015 to August 2015, to the MACU at CHBAH were reviewed. Patient demographics, diagnosis at admission, duration of stay, and outcomes were documented. Patients transferred to the medical ward, the Intensive Care Unit (ICU), or discharge. The leading causes of mortality were documented.

RESULTS

Of the 200 patients, 59% were females. The patients' mean age was 46 (17.2) years, and the mean duration of stay at the MACU was 1.45 (1.25) days. Non-communicable diseases accounted for 76% of admissions. The most frequently diagnosed conditions included: diabetic ketoacidosis acidosis (DKA) and hyperosmolar non-ketotic (HONK) (17.5%), non-accidental self-poisoning (16%), hypertensive emergencies (9.5%), decompensated cardiac failure (8%) and ischemic heart disease (7%). Infectious diseases comprised 14% of the diagnoses, of which cases of pneumonia were the most common (5%). Most patients (77.5%) were transferred to medical wards, 12% to ICU, while 10% demised at the MACU. The leading causes of death included sepsis (25%), DKA/HONK (20%), non-accidental self-poisoning (10%), and cardiac failure (10%).

CONCLUSION

Non-communicable diseases, particularly diabetic emergencies, were the leading causes of admission to the MACU at CHBAH. During the study period, high rates of case improvement, patient discharge, shorter hospital stay, and less mortality were observed. The leading cause of mortality was sepsis related.

Long-term prognosis of patients with permanent cardiac pacemaker indication in three referral cardiac centers in Cameroon: Insights from the National pacemaker registry

BACKGROUND

There is evidence that cardiac pacemakers improve symptoms and quality of life in patients with severe bradycardia. Globally, the number of pacemaker implantations is on the rise. However, the associated high-cost limits pacemaker's accessibility in low resource settings. This study aimed to investigate access to pacemakers and the long-term outcome of patients requiring a pacemaker.

METHOD

We conducted a cohort study in 03 health care structures in Cameroon. Participants aged at least 18 years with indication for a permanent pacemaker between January 2010 and May 2016 were included. Clinical profile, electrocardiography, pacemaker implantation parameters were recorded. Long-term survival was studied by event-free analysis using the Kaplan-Meier method.

RESULTS

In total, 147 participants (mean age 67.7±13.7 years, female 58.5%) were included. Fatigue (78.7%), dyspnoea (77.2%), dizziness (47.1%) and palpitations (40.4%) were the main symptoms while syncope was present in 35.7% of patients. The main indication for cardiac pacemaker was atrioventricular block (85.3%). Forty (27.2%) could not be implanted with 34 (85%) of participants highlighting cost of intervention as main reason. VVIR was the main mode of stimulation (70.5%). Of 125 patients in which follow-up was ascertained, 17(13.5%) died after a median survival time of 2.8 years post diagnosis [IQR: 1.8-4.2]. The survival curve was better in participants with a pacemaker with a Hazard ratio of 2.7 [CI: 1.0-7.3, P=0.045].

CONCLUSION

Our patients with severe heart blocks presented late and more than a quarter did not have access to pacemaker but its implantation multiplied the survival rate by 2.7 times at approximately 3 years post diagnosis. Improving early detection of heart blocks and access to cardiac pacing to reduce mortality shall be a key future priority.

Lifestyle modification and hypertension: prescription patterns of Nigerian general practitioners

Introduction

Implementation of lifestyle modification (LM), a cornerstone of hypertension control has been reported to be more challenging than pharmacotherapy. We studied the LM prescription patterns of general medical practitioners (GPs) in Lagos, Nigeria for blood pressure control.

Methods

GPs were assessed using anonymous self-administered questionnaire on the prescription of salt restriction, weight management, cessation of tobacco use, physical exercise, and consumption of DASH-like diet for blood pressure control. Chi-square, Fisher's exact and Student t-test were used to test for differences as appropriate. Logistic regression model was constructed to identify the determinants of adequate LM prescription.

Results

A total of 213 GPs (38% females) participated in the survey. LM prescription was over 90% for the following: salt restriction (96.7%), tobacco cessation (94.8%), weight management (94.4%). The remaining were 81.2% and 75.1% for healthy diet and physical activity respectively. The median LM prescription score (of the GPs) was 18.0 [15.0-50.0]. The single significant predictor of adequate LM prescription was total patient load of the GPs (AOR:0.98, 95% CI: 0.97-0.99, p=0.006). Eleven (5.2%), 190 (89.2%), and 12 (5.6%) GPs initiated LM prescription at blood pressure values >140/90mmHg, =140/90mmHg and <140/90mmHg respectively. LM initiation at BP <140/90mmHg was associated with female gender, shorter work experience, working in tertiary care facility and ignorance about hypertension prevention (p<0.05).

Conclusion

LM is widely prescribed for the treatment of hypertension, but rarely prescribed for its prevention in Nigeria. Interventions to reduce physician's patient load may engender improved LM prescription.

Cardiovascular risk factor burden in Africa and the Middle East across country income categories: a post hoc analysis of the cross-sectional Africa Middle East Cardiovascular Epidemiological (ACE) study

Background

A significant number of cardiovascular disease (CVD)-related deaths occur in developing countries. An increasing prevalence of CVD is associated with a change in the macro-economy of these countries. In this post hoc analysis, CVD risk factor (CVDRF) prevalence is evaluated across countries based on national income in the Africa and Middle East Region (AfME).

Methods

Data from the Africa Middle East Cardiovascular Epidemiological (ACE) study were used; a cross-sectional study in 14 AfME countries (94 clinics) from July 2011–April 2012, which evaluated CVDRF prevalence in stable adult outpatients. World Bank definitions were used to classify countries as low-income (LI), lower-middle-income (LMI), upper-middle-income (UMI) or high-income (HI) countries. Four thousand three hundred seventy-eight subjects were recruited where 260 (6%), 1324 (30%), 1509 (35%) and 1285 (29%) were from LI, LMI, UMI, and HI countries, respectively.

Results

Of all the CVDRFs evaluated, almost two-thirds of the study population across the national income groups had abdominal obesity and dyslipidemia. Countries in the HI category were associated with a higher prevalence of diabetes (32%), obesity (44%) and smoking (16%). UMI and HI countries were associated with higher clustering of CVDRFs where at least one-third of subjects having four or more CVDRFs. Lower income countries had lower blood pressure control rates and lower percentages of outpatients achieving LDL-cholesterol targets.

Conclusion

The burden of CVDRFs in stable outpatients is high across the national income categories in the AfME region, with HI countries showing a higher prevalence of CVDRFs. The high burden in lower income countries is associated with sub-optimal control of dyslipidemia and hypertension. Lowering the CVDRF burden would need specific public health actions in line with positive changes in the macro-economy of these countries.

Trial registration

The ACE trial is registered under NCT01243138.

Metabolic syndrome and occupation: Any association? Prevalence among auto technicians and school teachers in South West Nigeria

AIMS

To determine occupational association with metabolic syndrome among auto technicians and school teachers.

METHODS

One hundred and sixty six subjects were selected for this study. Clinical data was obtained while laboratory investigations including plasma glucose and lipid profile were performed. Statistical analysis was done with SPSS 20.0. P<0.05 was taken as statistically significant.

RESULTS

School teachers had significantly higher mean total cholesterol and LDL-cholesterol compared to auto technicians. Mean serum triglycerides was significantly higher among auto-technicians compared to school teachers in this study. The prevalence of some conventional cardiovascular risk factors was significantly higher among auto-technicians compared to school teachers: Impaired blood glucose (9.6% vs. 1.2%, p<0.05), hypertriglyceridaemia (18.1% vs. 7.2%, p<0.05) and low HDL-Cholesterol (47.0% vs. 37.3%, p<0.05) respectively. However elevated LDL-cholesterol (56.6% vs. 32.5%, p<0.05) was significantly more common among school teachers compared to auto-technicians. Based on the WHO and the Harmonized criteria, metabolic syndrome was more frequent among auto-technicians compared to school teachers. (8.4% vs. 1.2% and 19.3% vs. 7.2% respectively, p<0.05) CONCLUSION: The prevalence of metabolic syndrome appears to be significantly higher among auto technicians despite their high level of physical activity, exertion and education compared to teachers. This may be related to the increased occupational exposure to organic and inorganic materials from dust particles, oil and oil related matter and particulate matter among auto technicians. Prompt definitive evaluation of this concept and appropriate health education to encourage safety mechanism can reduce this burden of metabolic syndrome among auto technicians in Nigeria.

Primary care in the prevention, treatment and control of cardiovascular disease in sub-Saharan Africa

Cardiovascular disease (CVD) is the frontrunner in the disease spectrum of sub-Saharan Africa, with stroke and ischaemic heart disease ranked seventh and 14th as leading causes of death, respectively, on this sub-continent. Unfortunately, this region is also grappling with many communicable, maternal, neonatal and nutritional disorders. Limited resources and the high cost of CVD treatment necessitate that primary prevention should have a high priority for CVD control in sub-Saharan Africa. One major challenge of such an approach is how to equip primary care to respond promptly and effectively to this burden. We present a practical approach on how primary care in sub-Saharan Africa could effectively address the prevention, treatment and control of CVD on the subcontinent. For effective prevention, control and treatment of CVD in sub-Saharan Africa, there should be strategic plans to equip primary care clinics with well-trained allied healthcare workers who are supervised by physicians.

Keystones affecting sub-Saharan Africa's prospects for achieving food security through balanced diets

Socio-economic dynamics determine the transition from diets characterized by the risk of famine, to those characterized by the risk of diet-related non-communicable disease (DR-NCD). This transition is of particular concern in Sub-Saharan Africa (SSA) in which key socio-economic interactions that influence diet include economic growth and rapid urbanization; inequality and a growing middle class; and obesogenic food environments and an increasing prevalence of DR-NCD. In each case, countries in SSA are among those experiencing the most rapid change in the world. These interactions, styled as 'keystones', affect the functioning of other components of the food system and the diets that result. Data from the wealthiest quartile of countries in SSA suggest that these keystones may be increasing the risk of DR-NCD, widening inequalities in health outcomes due to unbalanced diets. To address this, new consumer and government capabilities that address these keystones are required. Food sensitive urban planning, supporting food literacy and fiscal management of consumption are examples.

Estimating the prevalence and awareness rates of hypertension in Africa: a systematic analysis

Background

The burden of hypertension is high in Africa, and due to rapid population growth and ageing, the exact burden on the continent is still far from being known. We aimed to estimate the prevalence and awareness rates of hypertension in Africa based on the cut off “≥140/90 mm Hg”.

Methods

We conducted a systematic search of Medline, EMBASE and Global Health. Search date was set from January 1980 to December 2013. We included population-based studies on hypertension, conducted among people aged ≥15 years and providing numerical estimates on the prevalence of hypertension in Africa. Overall pooled prevalence of hypertension in mixed, rural and urban settings in Africa were estimated from reported crude prevalence rates. A meta-regression epidemiological modelling, using United Nations population demographics for the years 1990, 2000, 2010 and 2030, was applied to determine the prevalence rates and number of cases of hypertension in Africa separately for these four years.

Results

Our search returned 7680 publications, 92 of which met the selection criteria. The overall pooled prevalence of hypertension in Africa was 19.7% in 1990, 27.4% in 2000 and 30.8% in 2010, each with a pooled awareness rate (expressed as percentage of hypertensive cases) of 16.9%, 29.2% and 33.7%, respectively. From the modelling, over 54.6 million cases of hypertension were estimated in 1990, 92.3 million cases in 2000, 130.2 million cases in 2010, and a projected increase to 216.8 million cases of hypertension by 2030; each with an age-adjusted prevalence of 19.1% (13.9, 25.5), 24.3% (23.3, 31.6), 25.9% (23.5, 34.0), and 25.3% (24.3, 39.7), respectively.

Conclusion

Our findings suggest the prevalence of hypertension is increasing in Africa, and many hypertensive individuals are not aware of their condition. We hope this research will prompt appropriate policy response towards improving the awareness, control and overall management of hypertension in Africa.

Cardiovascular risk factor burden in Africa and the Middle East: the Africa Middle East Cardiovascular Epidemiological (ACE) study

BACKGROUND

Increased urbanization in the developing world parallels a rising burden of chronic diseases. Developing countries account for ∼ 80% of global cardiovascular (CV) deaths, but contribute a paucity of systematic epidemiological data on CV risk factors.

OBJECTIVE

To estimate the prevalence of CV risk factors in rural and urban cohorts attending general practice clinics in the Africa and Middle East (AfME) region.

METHODS

In a cross-sectional epidemiological study, the presence of CV risk factors (hypertension, diabetes mellitus (diabetes), dyslipidemia, obesity, smoking and abdominal obesity) were evaluated in stable adult outpatients attending general practice primary care clinics. A rural population was defined as isolated (>50 km or lack of easy access to commuter transportation) from urban centers.

RESULTS

4,378 outpatients were systematically recruited from 94 clinics across 14 AfME countries. Mean age was 46 ± 14 years and 52% of outpatients were female. A high prevalence of dyslipidemia (70%) and abdominal obesity (68%) were observed, followed by hypertension (43%) and diabetes (25%). The vast majority of outpatients (92%) had at least one modifiable CV risk factor, many (74%) had more than one, and half (53%) had 3 or more. These findings were observed in both genders and across urban and rural centers. Among outpatients with pre-existing hypertension or dyslipidemia, many were not at their target blood pressure or LDL-cholesterol goals.

CONCLUSION

Cardiovascular risk factors are highly prevalent among relatively young, stable outpatients attending general practice clinics across AfME. The findings support opportunistic screening for CV risk factors whenever outpatients visit a general practitioner and provide an opportunity for early identification and management of CV risk factors, including lifestyle interventions.

Psychosocial stress but not hypertensive status associated with angiogenesis in Africans

AIM

Increased angiogenic factors [vascular endothelial growth factor-A (VEGF-A) and angiopoietin-2 (Ang-2)] have been associated with vascular dysfunction and hypertension. Black Africans undergoing rapid urbanization present with elevated blood pressure (BP) and we aimed to determine whether angiogenic factors are elevated in urban versus rural Africans with normal and elevated BP.

METHODS AND MATERIALS

Africans (n = 272), matched for gender and age, were recruited from rural and urban communities in South Africa. Omron HEM-757 BP data were obtained and angiogenic markers in plasma and serum were determined.

RESULTS

Urban African men displayed a higher (43.90%) hypertension prevalence compared with their rural counterparts (18.52%) and disturbed angiongenic factors. Adjusted VEGF-A concentrations were higher in urban men and women compared with their rural counterparts. Similar VEGF-A levels were observed in rural and urban hypertensives. Logistic regression analysis demonstrated that VEGF-A and Ang-2 levels were associated with psychosocial stress but not with hypertensive status in Africans [odds ratios 1.01-1.09 (95% CI 1.01-1.15), p ≤ 0.05].

CONCLUSION

Psychosocial stress per se was associated with disturbed VEGF-A and Ang-2. We suggest that hyperkinetic BP may act as compensatory mechanism when chronic psychosocial stress prevails, affecting vascular functioning and subsequent increased cardiovascular disease risk.

Low prevalence of hypertension with pharmacological treatments and associated factors

OBJECTIVE: To assess the determinants of the lack of pharmacological treatment for hypertension. METHODS: In 2005, 3,323 Mozambicans aged 25-64 years old were evaluated. Blood pressure, weight, height and smoking status were assessed following the Stepwise Approach to Chronic Disease Risk Factor Surveillance. Hypertensives (systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg and/or antihypertensive drug therapy) were evaluated for awareness of their condition, pharmacological and non-pharmacological management, as well as use of herbal or traditional remedies. Prevalence ratios (PR) were calculated, adjusted for sociodemographic characteristics, cardiovascular risk factors and non-pharmacological treatment. RESULTS: Most of the hypertensive subjects (92.3%), and nearly half of those aware of their condition were not treated pharmacologically. Among the aware, the prevalence of untreated hypertension was higher in men {PR = 1.61; 95% confidence interval (95%CI 1.10;2.36)} and was lower in subjects under non-pharmacological treatment (PR = 0.58; 95%CI 0.42;0.79); there was no significant association with traditional treatments (PR = 0.75; 95%CI 0.44;1.26). CONCLUSIONS: The lack of pharmacological treatment for hypertension was more frequent in men, and was not influenced by the presence of other cardiovascular risk factors; it could not be explained by the use of alternative treatments as herbal/traditional medicines or non-pharmacological management. It is important to understand the reasons behind the lack of management of diagnosed hypertension and to implement appropriate corrective actions to reduce the gap in the access to healthcare between developed and developing countries.

Cardiac surgery risk-stratification models

Risk models are widely used to predict outcomes after cardiac surgery. Not only is risk modelling applied in the assessment of the relative impact of specific risk factors on surgical outcomes, but also in patient counselling, the selection of treatment options, comparison of postoperative results, and quality-improvement programmes. At least 19 risk-stratification models exist for open-heart surgery. The focus of risk models was originally on pre-operative prediction of mortality. However, major morbidity is in general more common than mortality and the ability to predict only operative mortality is not an adequate method of determining surgical outcome. Multiple intra- and postoperative variables have been excluded in the majority of models and the possible effect of their future inclusion remains to be seen. The unique patient population of sub-Saharan Africa requires a unique risk model that reflects the patient population and levels of care.

Prevalence of cardiovascular disease in Gabon: a population study

BACKGROUND

Data supporting epidemiological transition from a predominant burden of infectious diseases to one of chronic diseases in Africa result mostly from hospital surveys.

AIM

To estimate the cardiovascular disease (CVD) burden in Gabon.

METHODS

The study was conducted in Ntoum (8765 inhabitants). All subjects aged greater or equal to 40 years were invited to participate. Participants were interviewed about CVD history and risk factors; they responded to questionnaires on claudication and angina and had a clinical examination, including lower limb pulse palpation and bilateral brachial pressure measurement. Subjects were considered to have CVD in case of history of CVD (coronary artery, cerebrovascular and peripheral arterial diseases), a positive questionnaire or an abnormal finding during clinical examination.

RESULTS

The study included 736 subjects (313 men; 423 women). Systolic hypertension was highly prevalent (up to 47.7% and 53.7% in men and women aged 50 to 60 years, respectively). Of the 382 patients with hypertension, 74 (19.4%) were treated and only 22 (5.8%) were considered to have controlled hypertension. Overall, CVD was identified in 98 (13.3%) cases. Overall and newly diagnosed CVD prevalence rates were 14.7% and 11.5% for men and 14.9% and 8.9% for women, respectively. The presence of CVD was associated with hypertension (hazard ratio [HR] 3.69, 95% confidence interval [CI] 2.21-6.16; P<0.0001). Hypertension was predictive of stroke (HR 4.57, 95% CI 1.26-16.50; P<0.05), peripheral artery disease (HR 2.03, 95% CI 1.03-4.00; P<0.05) and subclavian artery stenosis (HR 5.79, 95% CI 2.21-15.2; P<0.05).

CONCLUSIONS

Our findings provide strong evidence of ongoing epidemiological transition in Gabon, where CVD prevalence rates increase mainly with hypertension, affecting about one in six individuals aged over 40 years.

A systematic overview of prospective cohort studies of cardiovascular disease in sub-Saharan Africa

Background

Cardiovascular diseases (CVDs) are becoming increasingly significant in sub-Saharan Africa (SSA). Reliable measures of the contribution of major determinants are essential for informing health services and policy solutions.

Objective

To perform a systematic review of all longitudinal studies of CVDs and related risk factors that have been conducted in SSA.

Data source

We searched electronic databases from 1966 to October 2009. Published studies were retrieved from PubMed and Africa EBSCO. Reference lists of identified articles were scanned for additional publications.

Study selection

Any longitudinal study with data collection at baseline on major cardiovascular risk factors or CVD, including 30 or more participants, and with at least six months of follow up were included.

Data extraction

Data were extracted on the country of study, year of inception, baseline evaluation, primary focus of the study, outcomes, and number of participants at baseline and final evaluation.

Results

Eighty-one publications relating to 41 studies from 11 SSA countries with a wide range of participants were included. Twenty-two were historical/prospective hospital-based studies. These studies focused on risk factors, particularly diabetes mellitus and hypertension, or CVD including stroke, heart failure and rheumatic heart disease. The rate of participants followed through the whole duration of studies was 72% (64–80%), with a significant heterogeneity between studies (for heterogeneity, p < 0.001). Outcomes monitored during follow up included trajectories of risk markers and mortality.

Conclusions

Well-designed prospective cohort studies are needed to inform and update our knowledge regarding the epidemiology CVDs and their interactions with known risk factors in the context of common infectious diseases in this region.

Achieving blood preSsure goals sTudy in uncontrolled hypeRtensive pAtients treated with a fixed-dose combination of ramipriL/hydrochlorothiazide: the ASTRAL study

Background

Hypertension is a common cardiovascular disease, affecting adults worldwide and it accounts for up to 30% of all deaths. The need for better control of arterial hypertension justifies observational studies designed to better understand the real-life management of hypertensive patients. The ASTRAL study was primarily designed to evaluate the percentage of hypertensive patients achieving blood pressure goals after eight weeks of treatment with a fixed-dose combination of ramipril/hydrochlorothiazide (HCTZ).

Methods

The study was a multi-centre, non-comparative, open-label, observational study conducted in 36 centres in five sub-Saharan African countries, namely Cameroon, Congo Brazzaville, Democratic Republic of Congo (DRC), Madagascar and Nigeria. Four hundred and forty-nine men and women 18 years of age or older with hypertension not controlled by an ACE inhibitor, a diuretic or any other monotherapy or anti-hypertensive combination not containing a diuretic in a fixed dose were considered eligible for inclusion in this eight-week study. The study consisted of three visits, visit one (V1) at baseline, visit two (V2) after four weeks and visit three (V3) after eight weeks.

Results

The mean age of the patients was 54.7 ± 11.7 years (20–90 years) and most were categorised by the WHO criteria as either overweight or obese (71.6%). After four and eight weeks of treatment with the study drug, systolic and diastolic blood pressures significantly changed from baseline: –24.7/–14.2 mmHg (p < 0.001) and –31.7/–17.9 mmHg (p < 0.001), respectively. There were 60.2% of the non-diabetics on prior monotherapy who, at eight weeks, fulfilled the primary blood pressure goal for SBP and DBP, versus 26.5% of the diabetic patients, also on monotherapy. Few adverse events were reported, with facial oedema and dry cough recurring twice in two patients.

Conclusion

Fixed-dose combination of ramipril/HCTZ is therefore effective, tolerable and has a good safety profile for blood pressure control in black Africans.

The state of heart disease in Sudan

Cardiovascular disease (CVD) is the leading cause of mortality worldwide and an important cause of disability. In Africa, the burden of CVD is increasing rapidly and it is now a public health concern. Epidemiological data on diseases is scarce and fragmented on the continent.

AIM

To review available data on the epidemiology and pattern of heart disease in Sudan.

METHODS

Data were obtained from the Sudan Household Survey (SHHS) 2006, annual health statistical reports of the Sudan Federal Ministry of Health, the STEPS survey of chronic disease risk factors in Sudan/Khartoum, and journal publications.

RESULTS

The SHHS reported a prevalence of 2.5% for heart disease. Hypertensive heart disease (HHD), rheumatic heart disease (RHD), ischaemic heart disease (IHD) and cardiomyopathy constitute more than 80% of CVD in Sudan. Hypertension (HTN) had a prevalence of 20.1 and 20.4% in the SHHS and STEPS survey, respectively. There were poor control rates and a high prevalence of target-organ damage in the local studies. RHD prevalence data were available only for Khartoum state and the incidence has dropped from 3/1 000 people in the 1980s to 0.3% in 2003. There were no data on any other states. The coronary event rates in 1989 were 112/100 000 people, with a total mortality of 36/100 000. Prevalence rates of low physical activity, obesity, HTN, hypercholesterolaemia, diabetes and smoking were 86.8, 53.9, 23.6, 19.8, 19.2 and 12%, respectively, in the STEPS survey. Peripartum cardiomyopathy occurs at a rate of 1.5% of all deliveries. Congenital heart disease is prevalent in 0.2% of children.

CONCLUSION

Heart diseases are an important cause of morbidity and mortality in Sudan. The tetrad of hypertension, RHD, IHD and cardiomyopathy constitute the bulk of CVD. Hypertension is prevalent, with poor control rates. A decline in rheumatic heart disease was seen in the capital state and no data were available on other parts of the country. No recent data on IHD were available. Peripartum cardiomyopathy and congenital heart disease occur at similar rates to those in other African countries.

The nutrition transition in Africa: can it be steered into a more positive direction?

The objective of this narrative review is to examine the nutrition transition and its consequences when populations in Africa modernize as a result of socio-economic development, urbanization, and acculturation. The focus is on the changes in dietary patterns and nutrient intakes during the nutrition transition, the determinants and consequences of these changes as well as possible new approaches in public health nutrition policies, interventions and research needed to steer the nutrition transition into a more positive direction in Africa. The review indicates that non-communicable, nutrition-related diseases have emerged in sub-Saharan Africa at a faster rate and at a lower economic level than in industrialized countries, before the battle against under-nutrition has been won. There is a putative epigenetic link between under- and over-nutrition, explaining the double burden of nutrition-related diseases in Africa. It is concluded that it is possible to steer the nutrition transition into a more positive direction, provided that some basic principles in planning public health promotion strategies, policies and interventions are followed. It is suggested that sub-Saharan African countries join forces to study the nutrition transition and implemented interventions on epidemiological, clinical and molecular (genetic) level for better prevention of both under- and over-nutrition.

Distribution of hyperglycaemia and related cardiovascular disease risk factors in low-income countries: a cross-sectional population-based survey in rural Uganda

BACKGROUND

Data on non-communicable disease (NCD) burden are often limited in developing countries in Africa but crucial for planning and implementation of prevention and control strategies. We assessed the prevalence of related cardiovascular disease risk factors (hyperglycaemia, high blood pressure and obesity) in a longstanding population cohort in rural Uganda.

METHODS

Trained field staff conducted a cross-sectional population-based survey of cardiovascular disease risk indicators using a questionnaire and simple measurements of body mass index (BMI), waist and hip circumference, waist/hip ratio (WHR), blood pressure and random plasma glucose. All members of the population cohort aged ≥13 years were eligible to participate in the survey.

RESULTS

Of the 4801 males and 5372 females who were eligible, 2719 (56.6%) males and 3959 (73.7%) females participated in the survey. Male and female participants had a mean standard deviation (SD) age of 31.8 (18.4) years and 33.7 (17.6) years, respectively. The observed prevalences of probable diabetes (glucose >11.0 mmol/l) and probable hyperglycaemia (7.0-11.0 mmol/l) were 0.4 and 2.9%, respectively. Less than 1% of males and 4% of females were obese (BMI ≥30 kg/m(2)), with 3.6% of males and 14.5% of females being overweight (BMI 25.0-29.9 kg/m(2)). However, in women, the prevalence of abdominal obesity was high (71.3% as measured by WHR and 31.2% as measured by waist circumference). The proportions of male and female current regular smokers were low (13.7 and 0.9%, respectively). The commonest cardiovascular disease risk factor was high blood pressure, with an observed prevalence of 22.5% in both sexes.

CONCLUSIONS

Population-based data on the burden of related cardiovascular disease risk factors can aid in the planning and implementation of an effective response to the double burden of communicable diseases and NCDs in this rural population of a low-income country undergoing epidemiological transition.

Risk factors associated with intermediate and long-term mortality following vascular surgery in South African patients

Summary

There are few data on predictors of mortality following vascular surgery in South African patients. While in the developed world, peri-operative risk factors are also associated with intermediate-term survival, it is likely that the weighting and even the clinical risk factors may be different in South African patients due to the epidemiology of cardiovascular disease in developing countries. The aim of this study was therefore to determine risk factors associated with intermediate and long-term mortality in South African vascular surgical patients.

Design

A retrospective cohort study was conducted. Intermediate and long-term survival was determined by subsequent hospital visits or admissions. For patients who did not return to the hospital, the patient or patient’s next of kin was contacted telephonically. The outcome of the patient, and the time to the outcome following the surgical procedure were recorded. Bivariate and multivariate analysis was conducted using Cox regression analysis to determine predictors of intermediate-term mortality.

Results

Only hypertension and diabetes were associated with intermediate and long-term mortality at the bivariate level of analysis with p < 0.10. There was no co-linearity between hypertension and diabetes. Hypertension was the only predictor of intermediate and long-term survival retained in the multivariate model (hazard ratio 3.86, 95% confidence interval 0.83–15.4, p = 0.086).

Conclusion

In contrast to developed-world observations, peri-operative clinical risk indices were not associated with intermediate and long-term survival in South African vascular surgical patients. Instead, two risk factors that were identified in the South African National Burden of Disease study were associated with mortality. It appears that a ‘western lifestyle’ (and the presence of associated risk factors) may be more important predictors of intermediate and long-term mortality than peri-operative risk predictors of cardiac events in South African vascular surgical patients. This study highlights an important public health issue for the South African population where the most important determinants of mortality are continued exposure to risk factors (such as hypertension and diabetes) in the community, with little modification of these risk factors through primary health surveillance and management, even after surgical admission for pathology known to be associated with these risk factors.

Effect of systemic hypertension on right ventricular morphology and function: an echocardiographic study

BACKGROUND

Hypertension is an important cardiovascular risk factor worldwide. It is associated with left ventricular hypertrophy (LVH). Both diastolic and systolic dysfunction may occur in hypertensive heart disease. The ventricles are structurally and functionally interdependent on each other. This was an echocardiographic study intended to describe the impact of left ventricular pressure overload and hypertrophy due to hypertension on right ventricular morphology and function.

METHODS

One hundred subjects with systemic hypertension and 50 age- and gender-matched normotensive control subjects were used for this study. Two-dimensional (2-D), M-mode and Doppler echocardiographic studies were done to evaluate the structure and function of both ventricles. Data analysis was done using the SPSS 16.0 (Chicago, Ill). Statistical significance was taken as p < 0.05.

RESULTS

Age and gender were comparable between the two groups. Hypertensive subjects had significantly increased left ventricular end-diastolic dimensions, posterior wall thickness, interventricular septal thickness, left atrial dimensions and left ventricular mass and index. The mitral valve E/A ratio was reduced among hypertensive subjects when compared to normal controls (1.15 ± 0.75 vs 1.44 ± 0.31, respectively; p < 0.05). A similar pattern was found in the tricuspid E/A ratio (1.14 ± 0.36 vs 1.29 ± 0.30, respectively; p < 0.05). Hypertensive subjects also had reduced right ventricular internal dimensions (20.7 ± 8.0 vs 23.1 ± 3.1 mm, respectively; p < 0.001) but similar peak pulmonary systolic velocity. The mitral e/a ratio correlated well with the tricuspid e/a ratio.

CONCLUSION

Systemic hypertension is associated with right ventricular morphological and functional abnormalities. Right ventricular diastolic dysfunction may be an early clue to hypertensive heart disease.

The burden of non-communicable diseases in South Africa

15 years after its first democratic election, South Africa is in the midst of a profound health transition that is characterised by a quadruple burden of communicable, non-communicable, perinatal and maternal, and injury-related disorders. Non-communicable diseases are emerging in both rural and urban areas, most prominently in poor people living in urban settings, and are resulting in increasing pressure on acute and chronic health-care services. Major factors include demographic change leading to a rise in the proportion of people older than 60 years, despite the negative effect of HIV/AIDS on life expectancy. The burden of these diseases will probably increase as the roll-out of antiretroviral therapy takes effect and reduces mortality from HIV/AIDS. The scale of the challenge posed by the combined and growing burden of HIV/AIDS and non-communicable diseases demands an extraordinary response that South Africa is well able to provide. Concerted action is needed to strengthen the district-based primary health-care system, to integrate the care of chronic diseases and management of risk factors, to develop a national surveillance system, and to apply interventions of proven cost-effectiveness in the primary and secondary prevention of such diseases within populations and health services. We urge the launching of a national initiative to establish sites of service excellence in urban and rural settings throughout South Africa to trial, assess, and implement integrated care interventions for chronic infectious and non-communicable diseases.

Stroke at the university of port harcourt teaching hospital, rivers state, Nigeria

The case records of 202 consecutive adult Nigerian in-patients with stroke at the University of Port Harcourt Teaching Hospital (UPTH) were retrospectively reviewed. The mean age at presentation was 62.62 +/- 14.2 years. The male to female ratio was 1:1.2. The commonest risk factors were hypertension, diabetes mellitus, hypercholesterolaemia, older age and a previous history of stroke. Clinically, 67.3% had cerebral infarction (CI), while 27.7% had intracerebral haemorrhage (ICH). The peak age of events for both sub-types was the 7th decade. The case fatality was 55.4% for ICH and 23.5% for CI. Thus, stroke is associated with high mortality at the UPTH. Improved emergency care of stroke patients is needed while the setting up of dedicated stroke centres is advocated. A community-based study is necessary to provide more insight into the problem and also highlight the basis for appropriate intervention and policy.

A modern approach to tuberculous pericarditis

The human immunodeficiency virus (HIV) epidemic has been associated with an increase in all forms of extrapulmonary tuberculosis including tuberculous pericarditis. Tuberculosis is responsible for approximately 70% of cases of large pericardial effusion and most cases of constrictive pericarditis in developing countries, where most of the world's population live. However, in industrialized countries, tuberculosis accounts for only 4% of cases of pericardial effusion and an even smaller proportion of instances of constrictive pericarditis. Tuberculous pericarditis is a dangerous disease with a mortality of 17% to 40%; constriction occurs in a similar proportion of cases after tuberculous pericardial effusion. Early diagnosis and institution of appropriate therapy are critical to prevent mortality. A definite or proven diagnosis is based on demonstration of tubercle bacilli in pericardial fluid or on histologic section of the pericardium. A probable or presumed diagnosis is based on proof of tuberculosis elsewhere in a patient with otherwise unexplained pericarditis, a lymphocytic pericardial exudate with elevated biomarkers of tuberculous infection, and/or appropriate response to a trial of antituberculosis chemotherapy. Treatment consists of 4-drug therapy (isoniazid, rifampicin, pyrazinamide, and ethambutol) for 2 months followed by 2 drugs (isoniazid and rifampicin) for 4 months regardless of HIV status. It is uncertain whether adjunctive corticosteroids are effective in reducing mortality or pericardial constriction, and their safety in HIV-infected patients has not been established conclusively. Surgical resection of the pericardium is indicated for those with calcific constrictive pericarditis or with persistent signs of constriction after a 6 to 8 week trial of antituberculosis treatment in patients with noncalcific constrictive pericarditis.