Tuesday, 26 July 2011

Pulmonary Hypertension

Published in Panorama

Who is prone to Pulmonary Hypertension …

27 year old Suneila was feeling sick and she observed swelling on her feet and abdomen. On consulting her physician, he suggested a host of tests. The diagnosis made was shocking and irrevocable. Suneila was told she was suffering from Pulmonary Hypertension and that little could be done to help her.

What is pulmonary hypertension and who are the people affected by it? Dr.Balakrishnan, Consultant Cardiologist, Zulekha Hospital, Sharjah, explains, “Pulmonary hypertension is basically an increase in the blood pressure of the pulmonary artery, the blood vessels taking blood into the lungs for oxygenation. This situation creates an unphysiological status for the right side of the heart which is not used to high pressures. The right side of the heart generally works on low pressure system as compared to the left side of the heart.

Pulmonary hypertension may be classified as Primary and Secondary, depending upon whether the cause of the condition is unknown or known. Dr.Balakrishnan explains, “Primary Pulmonary Hypertension (PPH) is a condition in which there is no known cause for the increase in pressure in the pulmonary artery. It is seen more commonly in women in their second and third decades of life and is attributed sometimes to recurrent clots migrating from the venous system of the body, to the lungs. It is also associated with more number of pregnancies, though this is not a cause of PPH. But no age or gender is barred from being affected with pulmonary hypertension.”

Dr.Balakrishnan continues, “Pulmonary veins carry blood back from the lungs to the left side of the heart. For some unknown reasons, these veins undergo some narrowing and build up back pressure on the arterial side of the lungs. This can also lead to PPH. This narrowing itself has been sometimes attributed to the intake of certain herbal preparations, particularly by some African tribals. Some of the earlier weight-reducing drugs, now banned, are also believed to contribute to PPH. Having said that, the weight reducing drugs that are presently available to not belong to this category at all.”

Secondary Pulmonary Hypertension (SPH) is due to some secondary causes, explains Dr.Balakrishnan. “The most common cause in the developing countries, is attributed to rheumatic heart disease, a condition in which the valves of the left side of the heart, especially the mitral valve, is affected and it builds up the pressure in the left upper chamber of the heart, the atrium. This builds up the back pressure on the pulmonary veins and results in the arterial pressure also going up.”

Elaborating further on this build up of arterial pressure, Dr.Balakrishnan continues, “The arterial pressure goes up for two reasons: one, due to low oxygen because of lung congestion which produces an active constriction of the arteries of the lungs. Two, due to a purely mechanical factor where the left side pressure gradually builds up and therefore right side pressure also starts building up.”

“Some of the congenital birth defects of the heart, like holes in the heart, if they go uncorrected, can also contribute to SPH,” reveals Dr.Balakrishnan. “If these holes are large enough and go uncorrected, they shunt the blood from the left side to the right side. So the lungs get increased blood supply progressively. This increases the blood pressure in the pulmonary artery.”

SPH also may result from lung diseases like chronic bronchitis, emphysema leading to chronic low oxygen tension in the blood, resulting initially in spasm of the arteries. Later, there is thickening of the arteries and there is continuous elevated blood pressure in the pulmonary artery, explains Dr.Balakrishnan.

People living in high altitude areas face chronic low oxygen tension in the atmosphere. These people have a tendency for increased thickness of the arteries of the lungs and this also may lead to SPH, reveals Dr.Balakrishnan.

While all these situations of PPH and SPH are chronic in nature, Acute Pulmonary Hypertension can occur due to massive pulmonary embolism, explains Dr.Balakrishnan. “This happens when a clot from the venous side goes into the lungs and blocks a major artery. Since a part of the blood vessels are blocked, blood flow is diverted to the remaining arteries, causing an overload on them and the consequent increased pressure. These people develop pulmonary embolism and sudden acute distress which can even be fatal.”

What are the signs and symptoms of pulmonary hypertension? Dr.Balakrishnan explains, “These patients will have clinical features of high blood pressure on the right side of the heart, leading on to failure of the right side of the heart. They may not have much of lung signs which is very common in the left side heart failure. Here it is primarily, swelling of the feet, abdomen and very prominent neck veins. The other symptoms of the disease include:

1. Breathlessness on exertion.
2. Syncope or unconsciousness for a few minutes because of diminished blood supply to the brain.
3. Irregular heart beats
4. In milder cases, dizziness
5. Occasionally, the patient can have chest pain, especially in acute pulmonary hypertension when the clot travels to the lungs. The chest pain could mimic that of a heart attack.
6. Coughing up blood: this occurs only as a sequelae of an embolism to the lungs.

Is it possible that diagnosis of pulmonary hypertension is missed because the symptoms mimic that of other diseases? “Yes, it’s possible,” clarifies Dr.Balakrishnan. “It can be mistaken for myocardial infarction or heart attack. Swelling of the feet and abdomen may be lead one to think of liver or kidney problems in the absence of lung signs.

How is pulmonary hypertension diagnosed?
1. Clinical examination of the patient.
2. Chest X ray which would show a right side enlargement of the chambers of right side of the heart, dilated pulmonary arteries in the hilum of the lungs..
3. ECG
4. Echocardiogram
5. Doppler studies in the blood vessels of the pulmonary artery
6. Cardiac catheterization
7. Lung scan

Is it possible that an individual with pulmonary hypertension goes undiagnosed for years? “Yes, it does happen because when you see the patient for the first time, he can have an abnormally high pressure and nobody can pinpoint when it started! The way it has progressed to such a high level, it is likely that it has been there for a long number of years!” reveals Dr.Balakrishnan.

Is it then possible that the condition had set in during childhood itself and got diagnosed when the patient is in his or her 20s and 30s? “Very unlikely,” opines Dr.Balakrishnan. “Because when the condition develops in childhood as may happen in the case of children with congenital heart defects, they become much more sick and don’t do well. They become symptomatic much earlier and hence diagnosis cannot be missed.”

“It is possible,” says Dr.Balakrishnan that patients of pulmonary hypertension remain undiagnosed for up to 15 years and become symptomatic only in the last one year. From the 2nd decade of life onward, the condition can develop any time.”

Once diagnosed, what is the treatment modality and prognosis therefrom? Dr.Balakrishnan emphasizes, “PPH progresses very insidiously and the rate of progression of the condition can end fatally in as short as 1-2 years or can go on for 5 to 10 years. While there is no cure as yet for it, various medications and treatment modalities are tried, either singly or in combination, depending upon the factors contributing to the condition. These include vasodilators including calcium channel blockers, supplemental oxygen, anticoagulants, diuretics, etc.

What is the role of surgery in the treatment of pulmonary hypertension? Dr.Balakrishnan explains, “Lung transplant may be carried out in patients with PPH who have very high pressure and are not responding to any other medical treatment, depending upon availability of donor and patient’s financial capacity. Prognosis is quite good for the transplant patients. Transplant, however, is not undertaken on the very terminally ill patients or patients with advanced pulmonary hypertension.”

For SPH, the causes like valve diseases or holes in the septum of the heart can be corrected surgically, adds Dr.Balakrishnan.


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