Casuarina, Australia – The first evidence-based guidelines on how to
use echocardiography to diagnose rheumatic heart disease in those with mild asymptomatic disease have been published, by Dr Bo Reményi (Menzies School of Health Research, Casuarina, Australia) and colleagues in Nature Reviews: Cardiology .
The main aim of the new guidelines—which have been written by 21 key researchers in rheumatic heart disease and endorsed by the World Heart Federation (WHF)—”is to allow rapid and
early detection of rheumatic heart disease in those individuals who’ve got mild disease, because they have the most to benefit from early intervention, which is penicillin injections,” Reményi told heartwire. Starting this so-called secondary prophylaxis at an earlier stage of the illness than was previously possible can potentially reduce morbidity and mortality, she explained.
The advent of echocardiography has improved the diagnosis of rheumatic heart disease in the past decade—compared with the old method of using a stethoscope—but different criteria to define abnormalities of cardiac valve structure and function have been adopted in various guidances, leading to some confusion, say the researchers.
They hope the development of these new, internationally endorsed standardized diagnostic criteria will help in the design of new studies to evaluate the role of echo in rheumatic heart disease control.
Catching the disease early means penicillin treatment can stop at 21
Rheumatic heart disease is the consequence of acute rheumatic fever, which is caused by group A streptococci and usually presents in childhood, affecting five- to 14-year-olds. It affects over 50 million people worldwide, mainly in middle- and low-income countries and among some indigenous communities of industrialized nations, “so it’s a very important and prevalent problem,” explains Reményi. However, most people “do not recall any past history of acute rheumatic fever, probably because of poor medical services, and it is often never diagnosed, so we have a lot of children and adults who have rheumatic heart disease, but it hasn’t previously been picked up.”
At the moment, most people who get diagnosed with rheumatic heart disease have moderate or severe disease, and most of these already require surgery, which, for most people in the world, is unaffordable. These people also require lifelong injections of penicillin, every three to four weeks, to prevent recurrent attacks of the infection that cause worsening of the condition.
But if people could be caught earlier, when they have mild disease, which is usually asymptomatic, they need only take penicillin for up to 10 years or to the age of 21, she notes. In such cases, regular penicillin injections can eventually result in patients having no detectable disease. “By the time you reach your 20s, the risk is significantly lower than in your teens. If you only have mild disease you can safely stop penicillin at 21,” she notes.
“What we aim to see as a result of these guidelines is to reduce disease burden—reducing the amount of severe and moderate rheumatic heart disease in the world by facilitating early detection and management.”
The new recommendations list the WHF echocardiographic criteria for rheumatic heart disease, based on best available evidence, and define three categories of illness: “definite” rheumatic heart disease, “borderline,” and “normal.” A concise summary of the guidance—contained in four key boxes, which also include a list of criteria for pathological regurgitation, morphological features of rheumatic heart disease, and echocardiographic machine settings—is available online as supplementary information .
Criteria developed with portable echo in mind, but costs need to fall
Reményi says the criteria have been developed with the idea of portable echo technology in mind, since many of the places badly affected by rheumatic heart disease are in remote areas of the world. A recent project spearheaded by the American Society of Echocardiography, for example, used handheld echo to screen over a thousand symptomatic individuals in a remote corner of Northern India, turning up countless cases of rheumatic heart disease. But despite the fact that these devices are becoming more affordable, the very cheapest option is still $25 000 per machine on a heavily discounted basis, she notes, which is still unaffordable for many.
“It’s quite clear talking to physicians who are involved in this that the single biggest burden is the cost of the machines, because labor otherwise is cheap. Nurses and other healthcare workers can be trained to use these machines,” she notes.
But the availability of these devices “is still few and far between where they are needed the most,” she observes. She estimates that around 120 million at-risk children should be tested yearly for rheumatic heart disease, which would require around 10 000 portable echo machines.
“This is a very big issue that the WHF is trying to address by directly approaching companies to try to reduce the price of echo machines; that’s a persistent goal.”
She and her colleagues also note that the “ultraportable, handheld machines that have been marketed for point-of-care echocardiography in intensive-care and trauma units might provide a cheaper option,” but they point out that such devices “currently cannot perform either real-time measurements or continuous Doppler echocardiography.” So for the time being, the new diagnostic criteria “should not be applied to screening using handheld machines,” they stress.
Erratic supply of penicillin also a problem
Ensuring that people get penicillin injections once they have been diagnosed with rheumatic heart disease is also another key issue, says Reményi.
Constant supply of penicillin has been a huge problem, she says. “Over the past decade, the supply of penicillin has been inconsistent, and it has been a major issue in some places. Sometimes the supply is good, but then essentially the entire world runs out. Once again, there is a global initiative trying to liaise with drug companies to maintain a source of penicillin, which has been troublesome because penicillin is such a cheap drug and drug companies don’t invest a lot of their efforts in this; it’s not one of their highest priorities.”
And missing even one injection can have devastating consequences for a patient, she notes. “Missing a dose or two can be very harmful; the flare-up of the illness is related to a huge streptococcal infection, and in these communities, streptococcal infections are just endemic.”
Also vital to the mix is the attitude of affected patients regarding compliance with penicillin injections, which differs from place to place, she notes. For example, “in the Pacific islands and New Zealand, there is high uptake, and the population is very receptive because they all know someone who has died due to rheumatic heart disease. But in Australia, there are some difficulties with our indigenous population, which obviously needs to be answered because there’s not much point in detecting rheumatic heart disease if the treatment is not accepted and you cannot intervene.”