22. Specific lesions: Transposition of great arteries (TGA)

Hello after almost a year. 

In response to popular demand regarding information about specific defects of the heart I will aim to address each defect in a systematic fashion. I start today with a condition called Transposition of great arteries

This is a simple illustration of the condition.  To recap from one of the earlier posts:
The normal heart has 4 chambers, 2 on the right side and 2 on the left side.The right sided chambers contain oxygen poor or blue blood and the left sided chambers contain oxygen rich or red blood. The right and left sides of the heart are separated by a wall. ‘Blue’ blood from the right pumping chamber is pumped into the lungs through a vessel called the pulmonary artery. ‘Red’ blood from the left pumping chamber is pumped into the body through a vessel called the aorta.

In transposition of great arteries the two blood tubes are swapped across; the aorta arises from the right side and the pulmonary artery arises from the left side. This means that the blue blood from the right side circulates in the body resulting in a 'blue baby' and the red blood from the left side circulates in the lungs.

This condition is present right from the time the heart is formed at 6-8 weeks of pregnancy and can be detected during the ultrasound scan that is performed in early pregnancy. After birth the baby is noted to be blue as the oxygen levels in the blood are very low. If left untreated most of the babies with this condition will die within the first month of life and 95% will die within the first year of life. 

Sometimes these babies need urgent treatment after birth and a life saving balloon procedure may need to be performed (balloon atrial septostomy). This is done in order to improve the oxygen levels in the blood. This however is only a temporary procedure and the only definitive treatment is open heart surgery. This has to be carried out within the first few weeks of life and is called an Arterial Switch Operation. It involves swapping the blood vessels over so that they are connected to the correct side of the heart.






Although the operation carries a risk (success rate of around 90% in a good paediatric cardiac unit) the long term results of this procedure are very good and these patients go on to lead a near normal life.

If the child does not get prompt, timely treatment the risks of the operation increase. Also there is a point in time beyond which the arterial switch operation cannot be performed. In this case a less ideal operation called the atrial switch operation will need to be carried out.

In summary transposition of great arteries is a serious birth defect of the heart that needs early detection and timely treatment. Although the operation does carry some risk the long term outcome is generally very good and we expect most patients to lead a 'normal' life.

Please feel free to ask any questions that you might have.

21. Virundhinar Pakkam | Dr. Sangeetha Viswanathan,Pediatric cardiologists |...

20. Pulmonary Hypertension patient support group

May 5th - World Pulmonary Hypertension day 

Pulmonary hypertension is a severe life limiting condition where the blood pressure in the lungs gets elevated due to thickening of the blood vessels within the lungs. This can be due to various causes; in some patients there is no identifiable cause and this is called idiopathic pulmonary hypertension; in others, it may be due to lung disease; the third group of patients is our focus as they have a form of pulmonary hypertension that is potentially preventable. These patients suffer from a condition called Eisenmenger syndrome. In this condition pulmonary hypertension is a preventable complication of a heart defect that is present from birth.  If the heart defect had been detected and treated early during childhood the pulmonary hypertension could have been prevented and the patient would have had a normal lifespan and quality of life.

Birth defects of the heart occur in approximately 1% of all babies born today.They can present at various ages depending on the type and severity of the defect. Some severe defects are obvious right from birth but other less severe conditions may be detected only later in life. Children with heart defects can have breathlessness and feeding difficulties. They are also more prone to getting chest infections and have slow weight gain.

Delayed detection and treatment of birth defects of the heart can lead to permanent damage and high pressure in the lungs (pulmonary hypertension) making the patient unsuitable for definitive treatment like surgery or keyhole therapy. This underlines the importance of early detection and treatment of birth defects of the heart.

Once a diagnosis of Eisenmenger syndrome is made many patients are simply sent away with 'nothing can be done'. Although a complete cure may not be possible for these patients they do require regular follow up, medication and lifestyle advice on issues like pregnancy, contraception, exercise etc.
   

Until recently good medical therapy for this group of patients was not available and they were condemned to a life of gradual deterioration and early demise. Now, there are a wide range of medications that are available that can improve the quality of life of these patients and prolong their survival. The medications do come at a cost (between 750 and 5000 INR per month depending on the drug that is used) but they have been shown to improve the exercise capacity and quality of life of these patients and are indirectly believed to improve their long-term survival as well. Prior to starting medical therapy patients may require a cardiac catheter test to establish clearly that there is no scope for curative treatment.

Apart from medications these patients need counseling regarding various issues in life. Pregnancy in women with severe pulmonary hypertension should be strongly discouraged as it can lead to deterioration and death. Good advice regarding safe and reliable contraception should be given. Mild exercise like walking and swimming can be carried out but patients should be advised not to push themselves or participate in a competitive fashion.

Above all this, patients with pulmonary hypertension are often adolescents and young adults who suddenly find themselves having to deal with the burden of living with a condition without a cure. The doctor's consultation should allow them to express their doubts and apprehensions and help them face life with positivity and courage.

 To this end we have established a Pulmonary Hypertension Patient Support Group, which will function out of the CHIME office at MIOT hospital. We welcome all patients, families and members of the lay public affected by this cause to get involved with our movement and make our vision of eradicating preventable pulmonary hypertension a reality. Our first meeting was held on the 12th of April. Parents and children, came from places like Erode,  Vellore, Arkonam, and Thoothukudi and from Suburbs like Chrompet, Kolathur, Injambakkam. They shared their experiences and gained strength from each other. Parents said they always thought they were alone in this but they realized after coming to this meeting that so many people have been affected with PH. 

  

As a society we should aim to eradicate preventable pulmonary hypertension by early detection and treatment of heart defects in children. This can only happen with increased health education and awareness amongst the lay public and medical fraternity. Patients with pulmonary hypertension need support from their families, peers and the medical community to face the challenges that lie ahead.

I invite you to be part of this effort. Please email me on drsangeethaviswanathan@gmail.com for further correspondence

.

19. Sudan

Add caption

18. Infections and the heart

Patients with heart defects are at a risk of serious infections of the heart  called infective endocarditis. Bacteria and other microorganisms normally tend to live in the teeth and oral cavity. They can enter the bloodstream and cause infections in the heart especially if there is a defect in the heart like a hole or a faulty valve. These infections can be very serious and may even be life threatening. Thus a small hole in the heart which is usually a minor problem can have a serious and deadly complication in the form of infection.

It is very important therefore for patients with heart defects to look after their teeth carefully; brushing at least twice a day and seeking help early if  there are signs of dental infection. A trip to the dentist every 6 months to clean the teeth is also a good idea and will help detect problems early. If patients require open heart surgery they need to get dental clearance prior to the operation in order to avoid infection post surgery especially when artificial materials like artificial valves are being implanted.

Whether patients with heart defects need preventive antibiotics when they undergo various dental and general surgical procedures is open to debate and there is data available that there is no scientific basis for this practice. The medical profession is till somewhat unsure about what to do in this regard.

There is however no doubt that dental hygiene is very important in the prevention of infective endocarditis. Every patient with a heart defect should receive counselling regarding this when they visit their cardiologist.

17. A footnote on patients on blood thinning medications

I had failed to touch upon the important issue of pregnancy in patients who are on blood thinning medications. Hence this footnote...

Patients who are on blood thinning agents should plan pregnancy.  They should consult their doctor before they get pregnant so that their treatment can be altered to ensure that there is least risk to themselves and the baby. The anti-coagulation should not be completely stopped but the dose may be altered or the drug changed to a safer alternative.Warfarin (oral agent) at higher doses can cause malformations/deformities in the unborn baby and should be stopped and changed over to an alternative blood thinning agent (injectable) before the patient gets pregnant.

Patients who are on warfarin are troubled by the need for regular monitoring of INR and dose alterations. This situation however is likely to change in the future as newer agents are already in clinical use in the west that can be taken orally and do not need blood tests or dose alterations. These drugs however are currently beyond the reach of the average patient in India and much of the developing world.

16. Patients on blood thinning medications

A number of children and adults require medications that thin the blood. These medications are called anti coagulants and the main drug that is prescribed for this purpose is called warfarin.

When does a patient have to take anticoagulants?

Blood thinners are required in a variety of situations for example patients with metal valves in the heart, some patients in whom artificial materials are used during cardiac surgery, patients with some heart rhythm problems, patients who have had strokes due to clots in the brain etc.

These medications should ALWAYS be prescribed by a qualified practitioner

Do these medications need to be taken everyday? How long do they need to be continued?

Anticoagulants like warfarin are usually prescribed as long term therapy which need to be taken on a daily basis. The dosage of the drug needs to be adjusted based on a blood test called the INR (International Normalized Ratio). This test tells us how thin the blood is. The optimal level of INR varies depending on why the drug has been prescribed; for example patients with metal valves may need to have a higher INR value than patients with a heart rhythm problem. This ideal level needs to be individualized for each patient.

Why should the INR be maintained at a particular level?

The INR tells us how thin the blood is. If the INR is too low then the blood has not been thinned enough and there is a risk of clot formation in the bloodstream. If the INR is too high then the blood is too thin and there is a risk of bleeding. This is why INR needs to be maintained at an optimal level.


Are there any specific dietary precautions when taking blood thinners?

Blood thinning medications interact with certain foodstuffs and medications. This can lead to sudden changes in the INR. Patients who are on warfarin should avoid consuming large quantities of green leafy vegetables like spinach, broccoli etc. Excessive alcohol consumption should also be avoided. Certain juices like cranberry and grapefruit also create disturbances in the INR.

Certain medications like antibiotics can result in interactions with warfarin and a high INR. It is important that the patient should consult his or her doctor before starting any new medication along with warfarin.

What about activities?

Patients on warfarin can carry out normal activities but they should avoid contact sports like rugby, kabadi etc. This is because they are at increased risk of bleeding on impact. Children on warfarin can participate in physical non competitive sport but they will not be able to become professional sportsmen/women.