Preventing sudden death

Besides a healthy lifestyle, early recognition and detection of the underlying blockage of the heart arteries are vital to avoiding a fatal heart attack. Here are some essential tips to achieve that.

‘IT is impossible to die of a heart attack!” Can this statement be true? The answer is that with today’s medical advances, it can be true for most people. The most common underlying cause for sudden death from heart disease is the blockage of the heart arteries. Hence, avoiding a heart attack is key to preventing sudden death. Besides a healthy lifestyle, early recognition and detection of the underlying blockage of the heart arteries are vital to preventing death from sudden heart attacks.

No chest pain means no heart disease – true or false?

Myth: If you do not have chest pain, you will not die of a sudden heart attack.

Truth: According to the American Heart Association (AHA), 50 per cent of men and 64 per cent of women who die suddenly from a heart attack have no previous symptoms of the disease. Hence, blockage of the heart arteries (also termed coronary artery disease or CAD) is also called a silent killer.

Myth: If you are a female, your risk of developing CAD is low.

Truth: The lifetime risk of developing CAD if you live to at least 40 years is 49 per cent for men and 32 per cent for women. On the average, women develop CAD a decade later than men. However, while the increase in CAD is gradual for men over 60 years, it is exponential for women. Hence, contrary to expectations, more women than men die of CAD.

Myth: CAD is less important than other medical problems in women.

Truth: CAD kills more women than cancer, lung disease, Alzheimer’s disease, and accidents combined. Hence, in the United States, for men and women, heart disease remains the No 1 killer. In most developed countries heart disease is the No 1 or No 2 killer.

Myth: If there is significant blockage of the heart arteries, the typical symptom is exertional chest pain or discomfort (angina). Other symptoms are not related to the heart.

Truth: While the National Heart Lung and Blood Institute in the US states that angina is the typical symptom of underlying CAD, it also notes that many patients with significant CAD do not exhibit chest pain and may instead display other symptoms such as shortness of breath on exertion, neck pain, jaw pain, back pain or indigestion.

A negative test means no heart disease – true or false ?

Myth: A normal exercise treadmill test with no chest pain and no abnormal changes on the electrocardiogram (ECG or recording of the heart’s electrical pattern) means that there is no significant blockage of the heart artery.

Truth: A negative treadmill test only means that there is a lower likelihood of significant CAD; it does not mean that you do not have significantly blocked heart arteries. For every hundred patients with significant blockage of a major heart artery who undergo treadmill testing, only about 60 will show an abnormal treadmill test result. Treadmill testing has its limitations, and it is possible to have a normal result even in the presence of severe disease of all three major heart arteries.

Myth: Your doctor sends you to do a scan of the heart muscle’s blood flow which involves injection of radioisotopes and the result is normal. You can be 100 per cent sure your heart arteries are not blocked.

Truth: These heart radioisotope scans include Thallium scan, MIBI scan, Tetrofosmin scan and Rubidium PET CT scan. Even if there is 100 per cent occlusion of one major heart artery, as long as the other heart arteries are able to provide adequate cross flow, the scan can be completely normal. In addition, these isotopes circulate throughout the body, exposing the entire body to radiation. The radiation dose exposure is based on certain assumptions that the isotope will be passed out of the body within a certain time period.

However, no one can really be certain how long it takes for the isotope to be completely cleared from the body. In 2011, two patients who had undergone a Rubidium PET CT scan were found to have high radiation in their bodies more than one month post-scan. The US Food and Drug Administration (FDA) released an advisory stating that these two patients had excessive radiation exposure of approximately 90 millisieverts or mSv (the sievert is the unit used to measure the health effect of ionising radiation on the human body) which was “similar to the amount of cumulative radiation exposure some patients receive during cardiac diagnostic evaluations with other radionuclides”.

According to the US Nuclear Regulatory Commission, on average, the annual natural radiation exposure per person is about 3.1 mSv. Hence, based on the FDA statement, patients who undergo diagnostic cardiac scans with radioisotopes can potentially receive up to 30 years of annual radiation exposure.

Imaging the heart arteries

Myth: Invasive coronary angiography (ICA), which involves the insertion of a plastic catheter into the heart via the wrist or groin artery, is the only safe and accurate manner to diagnose the presence of significant blockage of the heart arteries.

Truth: There are two other non-invasive and safer ways to visualise the heart arteries without inserting tubes into the arteries.

If you undergo an ICA, there is a higher chance of finding normal or minor disease than significant disease. Data from the US published by Patel in New England Journal of Medicine show that about 40 per cent of ICA show normal arteries and about two-thirds show no significant disease.

Compared to ICA, computed tomography (CT) scan of the heart arteries is safer, less costly, has lower radiation dose, does not require hospitalisation, can provide three-dimensional images, can be completed in a few seconds and carries no risk of stroke or death.

ICA carries real risks. There are at least six prospective studies that have demonstrated that ICA is associated with 5 to 22 per cent incidence of minor “silent” strokes which can be detected on magnetic resonance imaging (MRI) of the brain.

ICA only allows two-dimensional visualisation of the inner lumen of the artery, and hence, unlike CT scan of heart arteries, ICA does not allow the visualisation of the extent of distribution of cholesterol deposit and calcium in the heart arteries.

Another method to visualise the heart arteries non-invasively is MRI scan of heart arteries. This technique carries no risk of X-ray radiation and does not require any injection. It is especially useful for young people where X-ray radiation should be avoided. As ICA carries real risks and is much more costly, increasingly more doctors are sending their patients for non-invasive scans of the heart arteries rather than ICA.

Medication forever after opening of heart arteries?

Myth: After opening of heart arteries with cylindrical meshes (stents), blood-thinning medication must be taken for the rest of the patient’s life. There is a risk that clots can form in the metallic stents if blood-thinning medication is stopped. Unfortunately, if there is a need for surgery, blood-thinning medication must be stopped and hence, there will be a real risk of stent clotting.

Truth: Not all stents are the same. Those who need to have stents implanted into the heart arteries should seriously consider opting for stents which will enable them to stop their blood-thinning medication. Polymer stents (“ABSORB” Bioresorbable Vascular Scaffold by Abbot Vascular, US), which do not contain metal, can be completely absorbed by the body in about three years. Blood-thinning medication can then be stopped.

There is also another new generation stent where the polymer coating can be absorbed leaving a thin metallic cylindrical mesh which will be covered by a new layer of cells within months. Once the metallic mesh is completely covered by a new lining of cells, blood-thinning medication can be stopped.

A study published in November 2015 in the Catheterisation and Cardiovascular Interventions journal reported that at six months, about 97 per cent of the area of the platinum chromium stent with absorbable polymer (“Synergy” stent by Boston Scientific, US) was covered by a new lining of cells. Hence, there is a very high likelihood of complete coverage of the stent by the end of one year.

Make the best decisions for your future

Here is a checklist to help you make the decisions you will not regret:

• No chest pain does not mean no heart disease.

• Consider getting your heart checked if you are experiencing shortness of breath or if you

  have multiple risk factors for heart disease which includes high cholesterol levels, diabetes

  mellitus, high blood pressure, and smoking.

• When doing a heart check, tests that allow heart artery visualisation are the most accurate for

  determining heart artery blockage.

• Always consider a non-invasive test first.

• If you are asked to do an ICA, consider the option of a CT or MRI instead and only do an

  invasive test if it is absolutely necessary.

• When undergoing a test that involves X-ray radiation, opt for a test that has not more than 3

  mSv of radiation (based on the AHA guidelines for women) and for women of child-bearing

  age, avoid radioisotope tests that will expose the entire body to radiation.

• Finally, if you need to have stents for heart arteries, do seriously consider new-generation

  stents that avoid the need for long-term blood-thinning medication.

2017-06-22T11:14:44+00:00