From the Heart: Call for Better African CV Research

February 09, 2010

February 9, 2010 (Maputo, Mozambique) — A new review is calling for concerted efforts to foster multidisciplinary research into cardiovascular diseases that predominantly occur in Africa and that are badly neglected [1]. Without this, it will be impossible to improve the medical care of patients with these conditions or develop effective preventive measures, say Dr Ana Olga H Mocumbi and Maria Beatriz Ferreira (Instituto do Coração, Maputo, Mozambique) in the February 16, 2010 issue of Journal of the American College of Cardiology.

Mocumbi told heartwire that for many of these conditions, knowledge of the epidemiology, pathogenesis, and management of the disease needs to be vastly improved. And almost nothing is known about some emerging cardiac manifestations of infectious diseases, which are only now becoming apparent. "We want to call the attention of the world, with a view to increasing research into these conditions, developing joint initiatives with European countries and the US, and creating collaborative projects between countries inside Africa."

We want to call the attention of the world, with a view to increasing research into these conditions.

Currently, efforts are hampered because research funding sources are rare--there are few industries and trusts, for example--and even when funding is available, the considerable "brain drain" that has occurred in Africa means there is a lack of expertise to administer such projects, she notes. Added to this are the concerns of some policy makers that investment into research for these cardiovascular conditions will interfere with efforts to control communicable diseases.

There is some hope, however, with recent initiatives including the Drakensberg declaration on the control of rheumatic fever/rheumatic heart disease in Africa, the initiation of the Pan African Society of Cardiology, and several projects studying the epidemiology of neglected diseases such as peripartum cardiomyopathy (PPCM) and endomyocardial fibrosis (EMF), as well as a pilot trial of a therapy in tubercular pericarditis.

"Initiatives such as these will hopefully increase awareness of local governments and the international scientific community regarding these neglected diseases," say Mocumbi and Ferreira, and might help retain high-quality local health personnel and researchers, they add.

Endomyocardial Fibrosis: Most Common Restrictive Cardiomyopathy

Mocumbi says two diseases in particular are huge burdens in Africa: EMF and rheumatic heart disease, and it is clear that the data currently available, for example from WHO, are inaccurate.

EMF is the most common restrictive cardiomyopathy worldwide, affecting primarily children and adolescents from sub-Saharan Africa, particularly Uganda, Mozambique, and Nigeria; it also occurs in India and Brazil. A recent study conducted by Mocumbi and colleagues and published in the New England Journal of Medicine [2] found a much higher prevalence of EMF than previously thought--almost 20% in a rural area of Mozambique. "Hence the importance of our own research to document what is really happening in the field," she says.

Right-sided EMF is the most common form of presentation, with chronic systemic venous hypertension, which leads to elevated jugular pressure, gross hepatomegaly, congestive splenomegaly, and ascites, with the mean survival time after diagnosis being just a few years. Ethnicity, poverty, malnutrition, allergy, dietary factors, infections, and toxic agents have all been postulated as etiological factors, but the exact cause and pathogenesis remain unknown.

Mocumbi says that while clinical presentation can lead to an easy diagnosis of EMF in endemic areas, echocardiography is important for confirmation, allowing differentiation between EMF and other conditions with similar symptoms, such as constrictive pericarditis, tuberculous peritonitis, and intestinal schistosomiasis. In EMF, echo shows increase in density and thickening of the endocardium, obliteration of the apices, valve dysfunction, restrictive filling pattern, severe atrial enlargement, and thrombi, she notes.

"The medical treatment has poor results, and surgery must be done in all symptomatic cases. However, surgery is technically challenging and is rarely performed due to lack of facilities and late presentation of the patients," she and Ferreira state. As part of her own research program, Mocumbi and colleagues have developed a tailored surgical technique, with some success [3].

Another cardiomyopathy with a high incidence in certain African countries is PPCM, says Mocumbi. Although much more research is required, that which has been conducted shows the prevalence of this condition varies widely, from one in 1000 deliveries in South Africa to one in 100 in Nigeria, for example. The latter highlights the importance of taking into account local customs and traditional healers when conducting research, says Mocumbi, as the customary practice of feeding women foods rich in sodium and heating the body after childbirth might play a role in the high incidence of PPCM seen in Nigeria, she notes.

Rheumatic Heart Disease: Major Cause of Disability and Premature Death

Another example of local research surpassing all previous estimates for prevalence showed that echo screening was likely to detect more than 10 times as many cases of rheumatic heart disease as clinical screening in Mozambique and Cambodia. The prevalence of rheumatic heart disease found in Mozambique, 30.4 per 1000 schoolchildren, was almost twice the highest previously reported number from a study in Kinshasa, says Mocumbi.

And rheumatic heart disease remains the most common form of acquired cardiovascular disease in children and adolescents in sub-Saharan Africa, where "it is a major cause of disability and premature death and constitutes a serious problem in surviving adults," she and Ferreira note.

There are many challenges in dealing with rheumatic heart disease, including lack of awareness from health personnel and the public, the difficulty of accessing clinics and the affordability of penicillin, and the absence of structured national programs for prevention and control of the disease in most African countries, they point out.

"Local research into this condition is crucial to allow the design of guidelines for its diagnosis and management, taking into account the unique demographics and phenotypes found in these settings," they observe.

Emerging Cardiac Manifestations of TB and Schistosomiasis

In addition, new cardiac sequelae emerging as a result of the HIV epidemic and other coinfections in Africa are another pressing issue, says Mocumbi, including tubercular pericarditis and cardiopulmonary schistosomiasis.

These cardiac manifestations are florid and very new; they have not been described previously.

"These cardiac manifestations are florid and very new, even to us, in HIV-infected patients and have to be studied; they have not been described previously," she explains.

Other diseases that are common in Africa, with severe cardiac symptoms and in dire need of further research, include: Burkitt's lymphoma, the most common childhood malignancy in Africa, linked to infections such as Epstein-Barr virus, malaria, and HIV, which can result in intracardiac masses, right heart failure, or pulmonary embolism; Takayasu's arteritis, occurring in regions endemic for TB and again mainly affecting children, causing renovascular hypertension; and subvalvular aneurysms, which are false left ventricular aneurysms of unknown etiology that may produce symptoms in the second or third decade of life. Patients typically present with sudden, acute left-sided heart failure with an insidious appearance of cardiac decompensation with angina, say Mocumbi and Ferreira.

"[Nongovernmental organizations] and health professional organizations in Africa must be the stakeholders in the process of acquiring accurate data on the burden of neglected cardiovascular conditions in Africa, in order to advocate changes in health policies and priorities for research in the continent," the doctors from Mozambique conclude.


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