In the initial phase of ARF, all the tissues of the heart may be involved: the muscle, its inner and outer lining, and the valve leaflets. The patient is acutely ill, and may even go into heart failure, usually due to leaking of the mitral and/or aortic valves. The mortality rate of ARF is 2-5%.
In developing areas of the world, ARF and rheumatic heart disease are estimated to affect nearly 20 million people and are the leading causes of cardiovascular death during the first 5 decades of life. Every one of these cases could have been avoided with timeous and appropriate antibiotic therapy. Managing ARF is best left to specialists for the best chance of avoiding permanent valve damage.
The most common long-term problems of ARF are due to the cross-reaction of antibodies with the tissues of heart valves: this inflammatory reaction causes thickening and scarring of the leaflets which cause them to either become stiff and narrowed or to leak. The most often affected valve is the Mitral valve, closely followed by the aortic valve. Repeated GAS throat infections aggravate the valve damage, so patients with established valve lesions may need to use continuous low-dose penicillin for many years to prevent recurrent ARF.
Valves inside the heart keep blood flowing in one direction only- from the right heart chamber to the lungs, and from the left heart chamber to the body. Unless heart valves function normally, blood cannot be kept circulating in this forwards-only direction.
There are four valves inside the heart. Two inlet valves – called Tricuspid and Mitral – open to allow blood to enter the heart’s ventricles (pumping chambers). When they close correctly, blood cannot leak back out during a contraction, and is instead forced out forwards, through the open outlet valves – Pulmonary and Aortic- to go to the either the lungs or the general body circulation.
Regardless of the cause, there are only three basic ways heart valves’ function can be damaged: they either become
- narrowed (stenosis) or they become
- leaky (incompetent/ regurgitant) or
- a combination of the two.
Narrowed valves prevent enough blood passing through the opening, whilst leaky valves don’t close properly, allowing blood to leak backwards, instead of flowing for¬wards only.
RISKS OF VALVE DAMAGE
Abnormal tissue in the body (i.e. damaged heart valves) is more predisposed to infection. Our immune system can deal with the occasional bacterium that may get into our bloodstream. But abnormal heart valves tissue is no longer smooth and “non-stick”, and a bacterium easily shelters there, where it can multiply to form a colony so large that it causes an illness called Infective Endocarditis (IE) with many serious complications and a mortality rate of up to 27%.
Any person with a damaged valve is thus at risk, and must follow a strict protocol of antibiotic use before any procedure known to allow bacteria to enter the bloodstream e.g. visits to the dentist (even just for a filling) and dental hygienist, or any surgery, even minor. Failure to do this can result in IE.
A damaged (= abnormal) valve disrupts normal heart function, and over years may cause symptoms which at first can be managed with medication (e.g. heart failure) but may eventually need open-heart surgery to replace the faulty valve. This is a crucial point in a young person’s life.
A biological valve may be used (pig valve) which has a shorter life span, and will thus need replacing after 10-15 years at best. However, these valves do not predispose to clot formation, so there is no need to use lifelong Warfarin to thin the blood. Because Warfarin can cause foetal abnormalities, a woman who still wants to have children can only be given a biological valve, even though this means another operation later. Males or women who have completed their families may be offered a mechanical heart valve instead. These valves made of pyrolitic carbon have an indefinite life span, but because of their tendency to clot, patients with these valves must use lifelong Warfarin.
Prophylactic antibiotic use is even more crucial for people with artificial heart valves. IE on a prosthetic valve can be even more life-threatening, with the formation of bacterial growths and clots on the valve, and/or an abscess all the way around the valve frame which can cause the whole valve apparatus to tear loose from the heart. Emergency surgery may be needed in these cases, but operating in the presence of the infection has a much higher mortality rate.
BACK TO SQUARE ONE – PREVENTION
All of this is preventable with basic health care awareness, and appropriate treatment of throat infections in children and young persons. Appropriate penicillin therapy is inexpensive and can prevent a lifetime of illness, complications and even death.
DO NOT IGNORE THAT SORE THROAT – CONSULT YOUR DOCTOR.
Persons with known valve problems or replaced valves, es¬pecially if on Warfarin, should wear a Medic Alert tag – this could be life-saving in an emergency situation. Contact your doctor for a Medic Alert application form.