Valvular Heart Disease in Emerging Countries: A Guide

Valvular heart disease in emerging countries is overwhelmingly rheumatic heart disease: valve damage left behind by streptococcal throat infections in childhood, sustained by poverty and poor access to care rather than by genetics. It strikes children, young adults and pregnant women, progresses silently for years, and too often reaches a specialist only once the patient is in advanced, barely reversible heart failure.

That is the diagnosis of the problem set out by Dr. Biswarup Purkayastha, Consultant – Heart & Lung Transplant and Vascular Surgery, Artemis Hospitals, Gurugram, India, in a masterclass for doctors across Africa on the challenges of valvular heart disease in emerging countries. A cardiothoracic surgeon who regularly reviews echo reports and referrals from the continent, he locates the failures in the system around the patient: access to echocardiography, the quality of echo reports, the timing of referral and the training of the doctors and nurses who see patients first.

This guide covers the burden, the biology and the gaps. Two companion articles go deeper: what a useful echocardiogram report and referral package must contain, and when to refer, how to treat in the meantime, and the four T's framework.

How large is the burden of valvular heart disease in emerging countries?

Rheumatic heart disease is far more common in sub-Saharan Africa than in the rest of the world. On the global prevalence maps Dr. Purkayastha presented, sub-Saharan Africa sits in the highest prevalence band, well above the global age-standardised prevalence of about 514 per 100,000 population. The same high band appears in parts of Latin America and the southern regions of Africa, and the pattern is almost pan-African, with the exception of a few North African countries.

Move north and the picture changes. Libya, Egypt, Algeria and Morocco show far lower rates, and continental Europe, the United States and Canada sit in a low-prevalence band. The geography matches the distribution of poverty and health-system capacity, not the distribution of any population group.

Dr. Purkayastha's conclusion is blunt: in the emerging world, valvular heart disease is as big a killer as coronary artery disease, if not bigger, and it deserves to be tackled with the same seriousness that health systems now bring to diabetes and coronary disease.

Are Africans genetically predisposed to valvular heart disease?

No. Africans are not genetically or racially predisposed to valvular heart disease, and the clearest evidence comes from the valve diseases that rheumatic fever does not cause.

• Calcific valve disease, the age-related calcification that narrows valves in older adults, is at its lowest among people in Africa. Dr. Purkayastha pointed to parts of Africa with rates far below the global average, while continental Europe, Russia and the former Soviet countries, Canada, New Zealand and parts of Latin America reach rates many times higher. He links the high-prevalence regions to diets rich in fat and calories.
• Degenerative mitral valve disease follows the same pattern. It is more common in populations of European descent in North America, Europe, parts of Russia and Latin America, and among the lowest in Africa.

If African valves were intrinsically weaker, these degenerative diseases would be common too. They are not. As Dr. Purkayastha put it, people in Africa do not have bad valves. What they lack is access to good quality healthcare, to good quality antibiotics and to community surveillance programmes, and that is why rheumatic heart disease affects them so heavily.

He drew a contrast with the far south of the continent. Botswana, Mozambique and South Africa show a high prevalence of coronary artery disease, which he attributed to an immigrant Caucasian population and its genetic predisposition. He calls the divergence between sub-Saharan Africa and the north of the continent "the sub-Saharan challenge".

What causes rheumatic heart disease?

Rheumatic heart disease begins with a sore throat. Group A streptococcal pharyngitis in a child can trigger acute rheumatic fever, an immune reaction that inflames the heart. Repeated attacks scar the valves, most often the mitral valve and then the aortic valve, leaving them narrowed (stenosis), leaking (regurgitation) or both.

The conditions that let this cycle run are social. Dr. Purkayastha lists them directly:

• Poverty and overcrowding, with many people sharing small living spaces.
• Poor sanitation and hygiene, which he describes as ideal breeding conditions for streptococcal organisms to cause sore throats in children.
• Low literacy, which means low awareness and little understanding that the disease must be taken seriously.

Because the drivers are socioeconomic, prevention rests on public health measures: prompt antibiotic treatment of streptococcal sore throats, long-term penicillin prophylaxis for anyone who has had rheumatic fever, and follow-up that catches valve damage before it becomes irreversible.

Valvular heart disease in the Asia-Pacific region

The Asia-Pacific region, the other large emerging region Dr. Purkayastha addressed, shows a related but distinct picture.

• Rheumatic heart disease remains the most common cause, still reasonably prevalent in low and middle-income countries, in certain pockets of India, in parts of Southeast Asia and in several Pacific island nations.
• Bicuspid aortic valve disease, Dr. Purkayastha notes, appears more often among the indigenous populations of the Pacific islands. A bicuspid aortic valve has two leaflets instead of the usual three and tends to narrow or leak earlier in life.
• Smaller body size brings smaller valve annuli (the rings in which the valves sit). Small annuli limit the size of prosthesis that can be implanted and raise the risk of patient-prosthesis mismatch at valve replacement.
• Degenerative valve disease is rising, because average life expectancy has climbed into the high 60s and 70s, which was not the case 20 to 25 years ago.

The result is a double burden: a persistent load of rheumatic disease in the young and a growing load of degenerative disease in the old.

Why valvular heart disease presents late in young patients

Valvular heart disease presents late because rheumatic valve disease progresses silently for years in children and young adults, and without a robust training programme for frontline staff it is not caught in time. In Western countries valvular heart disease is mostly a degenerative disease of the elderly. In Africa, Asia and the Asia-Pacific it is primarily a disease of children and young adults, because rheumatic heart disease dominates. Dr. Purkayastha summarises the profile in three phrases: a younger population, silent progression and severe complications.

The course is indolent, and patients remain asymptomatic for years. When they finally reach a specialist, they are in decompensated heart failure: unable to walk, unable to breathe, on very high doses of diuretics and restricted in their fluid intake. He describes them as having waited in the community like "sitting ducks", unaware of a valve disease that has progressed a long way.

Two presentations stand out:

• Neglected regurgitant lesions. Leaking valves are often ignored because doctors assume regurgitation has a longer natural history before it becomes severe. By the time these patients present, structural damage has caused heart failure that could have been completely prevented had they come to a clinic 10 or 15 years earlier.
• Young mothers decompensating in pregnancy. It is not uncommon for a woman in her second or third pregnancy to present with severe volume overload, with a history of uncomplicated earlier pregnancies. Pregnancy expands blood volume and raises cardiac output, and a damaged valve that coped before can no longer do so.

At the far end of the spectrum, Dr. Purkayastha has seen patients whose rheumatic heart disease began about ten years earlier and who now have left heart failure so severe that they need mechanical circulatory support, a left ventricular assist device (LVAD, an implanted pump that takes over the work of the failing left ventricle) or listing for heart transplantation. Those options are covered in his separate masterclass on LVADs as a bridge to transplant.

Gaps in valvular heart disease care: access, reporting, workforce

Dr. Purkayastha groups the obstacles into access, infrastructure and workforce.

Access to diagnosis. Echocardiography remains the gold standard, but machines and trained technicians are scarce and the cost is prohibitive. He cited a figure of about US$250 for a quality echocardiogram and report in parts of Africa, against an average monthly income of about US$150 in sub-Saharan Africa. Nearly two months of wages for one scan makes echocardiography, in his words, "not a reality, but a distant dream". Rural communities face geographic barriers on top of cost, with little or no access to the few urban centres doing a reasonable job.

Non-standard reporting. Many echo reports that reach him from Africa do not quantify the lesion, which leaves the specialist unable to judge severity or timing. The companion article on echo reports and referral packages sets out exactly what should be measured.

Infrastructure and workforce. There is a severe shortage of specialists, often not one qualified specialist per million population or per designated territory, and a shortage of primary care facilities. Nurses and general practitioners are not always sure when intervention is needed, what to do, or how to communicate the problem to the referring team.

Monitoring. Patients with valve disease in heart failure need regular blood work, but laboratories are few. Dr. Purkayastha sees patients with reports more than a year old, which he regards as irrelevant to their current state.

How valvular heart disease is managed: from diagnosis to intervention

Dr. Purkayastha described the pathway as follows:

1. Diagnosis by good quality echocardiography that is accessible and affordable enough to support screening programmes, supplemented by point-of-care ultrasound (a scan done at the bedside or in the clinic with a compact machine) and portable echo devices taken into high-risk and socioeconomically challenged communities.
2. Follow-up and medical management, which some doctors in Africa already do well: periodic imaging, risk stratification, reliable medicines, dental hygiene, patient education and regular penicillin prophylaxis.
3. Basic interventions such as closed mitral valvotomy and balloon mitral valvotomy, which can buy a reasonable amount of time once medical therapy has reached its limit.
4. Definitive treatment by valve surgery or, increasingly, transcatheter therapy.

He also pointed to where the field is heading: artificial intelligence to support diagnosis of valve disease in the community, genomic markers to study whether some patients are more prone to the disease, and patient forums that group people with similar problems so they can support one another. Proof-of-concept studies and collaboration with teams that are further ahead, he argues, are what keep a service current on whom to refer, when, and what information matters.

The detail of medical treatment, intervention and referral timing is in the four T's article. For the surgical options themselves, see advances in heart valve surgery, transcatheter aortic valve implantation (TAVI) for aortic stenosis and minimally invasive valve surgery techniques, each from a separate masterclass.

The four T's: a framework for the solution

Dr. Purkayastha's answer to the problem is a framework he calls the four T's for Africa:

• Train the doctors, through observerships, training camps and operating together, so that local teams can identify and manage valve disease.
• Time the referral, so that patients reach a specialist while something can still be done.
• Treat the patient with the tools available: penicillin, anti-failure medication and diuretics.
• Telemedicine, so that a local doctor can get specialist guidance on how to manage, stabilise and, if needed, transfer the patient.

His central conviction is that capacity building, not episodic surgical missions or costly medical evacuation, is what will change outcomes. The questions raised after the session are on the Live Discussion page, and his wider work on heart failure and coronary artery disease in Africa and pulmonary hypertension is covered in separate guides. More on the specialty is on the cardiology hub.