In my previous article, I had discussed some basic facts about cancer. In spite of all the major improvements in diagnosis and treatment for different types of cancer, the eventual cure remains an elusive goal. In modern medicine, it is the prevention of a particular disease that is almost as important as its treatment. And in this area heart disease is perhaps the poster child for the combined approach in decreasing the incidence as well as improving the treatment.

Heart disease is of many types. First of course are the heart defects or abnormalities a child is born with. These can be of two major types. The first one includes those where the heart chambers are deformed or abnormally connected. In children with such abnormalities, unless some form of corrective surgery or ‘palliative’ intervention is performed almost immediately after birth, the child might not survive. As diagnosis as well as treatment has improved, early corrective surgery even during the first few days of life or else palliative interventions have become much more successful.

Palliation means some medical intervention that allows a patient with a serious problem to survive a critical situation so that a definitive corrective treatment can be performed at a later date and under less stressful circumstances both for the patient and the physicians. Until the development of the heart lung machine in the early fifties, palliative procedures were the only available treatment for most heart problems.

The second type of heart abnormalities a child is born with are mostly those with abnormal connection between different chambers of the heart. A child can survive for many years if these abnormalities are not too severe. That said, eventually most of the abnormal connections have to be treated otherwise permanent changes occur in the circulatory system leading to severe disability and an early death.

Prevention of ‘congenital’ (present at birth) heart disease is a major challenge. Improvement in genetics is eventually going to prevent many, if not all, such ‘born with’ heart abnormalities as well as those in other organ systems. But we are not there yet and might not be for quite a while.

Read also: Heart disease-II

The next category of heart diseases is those that are acquired during childhood or later in life. Of these the most commonly acquired heart disease in children and young adults is ‘Rheumatic Heart Disease’ (RHD). Children with a ‘strep’ (the bacteria, streptococcus) throat infection can develop a reaction to this infection leading to joint pains (rheumatism-growing pains) and fever. If such infections happen repeatedly then the inner lining of the heart especially that on the heart valves can become damaged. RHD can be prevented if children with strep throat are treated early with appropriate antibiotics.

In old medical parlance, Rheumatic Fever ‘licks the joints but bites the heart’. Over a period of time the damaged heart valves become progressively worse. These valves can either become narrow (stenosis) and impede the flow of blood or become fixed in a semi-open condition allowing the blood to come back (regurgitation). Either condition if severe requires treatment. The valves most often damaged are the ones on the left side of the heart.

The history of heart surgery in the older patient starts with the surgical treatment of narrowed heart valves especially the one between the left upper chamber and the left lower chamber of the heart (Mitral Valve Stenosis) that is involved in almost eighty per cent of all patients with RHD. The second most often involved is the valve between the pumping left chamber of the heart and the big artery leading to the rest of the body. This is the Aortic valve.

The first surgical attempt to open a narrowed mitral valve occurred in 1923 in Boston by Eliot Cutler when he inserted a knife into the beating heart to slice open the narrowed valve. In 1925 in England, Sir Henry Souttar put a finger into a beating heart and successfully pushed open the narrowed mitral valve. This was called finger fracture. However, it was only twenty years later that this operation was popularised by Harken and Bailey in the United States and Brock (later Lord Brock) in England.

After graduating from King Edward Medical College, I served as house surgeon in the Department of Cardiac Surgery in Mayo Hospital during most of 1971. At that time almost all of the heart surgery being done was closed heart finger fracture of the mitral valve. During my ten months as house surgeon, I scrubbed (participated) in about ninety such operations. Dr. Aslam Cheema, one of the first American trained heart surgeons in Pakistan ran that department and performed those operations at that time. Most patients that were once candidates for finger fracture operations can now have their valves opened up with balloons during catheterisation procedures.

Read also: Heart disease-III

After the development of the heart lung machines it became possible during surgery to bypass the heart and to open the heart up. This allowed all sorts of operations including the repair as well as replacement of the damaged heart valves. Different types of metallic and nonmetallic heart valves were developed that were used to replace a patient’s own heart valve. The nonmetallic or ‘biological’ heart valve prostheses are made from animal tissue including the heart valve of a pig. The pig valve for those that wonder about such things is approved by religious authorities for use in Muslims.

Roughly two per cent of the general population develops mitral valve abnormality due to an innate weakness in the valve tissues. This can produce a leaky valve but most of these people never require any surgery or repair. A similar situation can occur in the aortic valve leading to a leaky valve. Also as people get older, aortic valves become hardened and narrowed. The major new development in treatment of damaged heart valves is the catheter replacement of aortic valves (TAVR) in older and sicker patients. Also catheter techniques are being developed to take care of leaky mitral valves.

The one problem that persists is that all patients with mechanical heart valve prostheses require lifelong blood thinning medicines that can have their own problems especially in young women that get pregnant. Because of blood thinners and bleeding problems during menstruation and pregnancy every effort is made to repair rather than replace abnormal mitral valves in young women.

The use of biological valves is preferred in older patients since these types of valve prostheses do not require lifelong blood thinners. However, biological valves do not last as long as mechanical valves so the expected longevity of the valve prosthesis has to be weighed against the expected longevity of the patient.

Another problem with diseased heart valves as well as valve prostheses is that they are susceptible to infection due to any situation that causes bacteria to enter the blood stream. This includes dental work, endoscopy procedures and most operations. In all these situations antibiotics are given to minimise the chance of valve infection (endocarditis).

Next time I will discuss diseases of the arteries of the heart (coronary disease) that produces heart attacks and is still the most common cause of death in western countries as well as Pakistan.