Heart Calcium Scan
Heart calcium scan also known as Coronary Calcium Scan is what the doctor will use to look for calcium deposits in coronary arteries. Such calcium deposits can narrow arteries and thereby increase heart attack risk. The result of this scan is called Coronary Calcium Score. Heart calcium scans are non-invasive techniques to measure the amount of calcium in the walls of coronary arteries – arteries that supply heart with blood. This is an indication that they may develop coronary artery disease.
Why heart calcium scans?
These scans show a higher risk of having a heart attack or any other problems before any symptoms of heart disease become obvious. However, the American College of Cardiology does not recommend routine heart scans on people who do not exhibit any symptoms of heart disease and who do not smoke or have cardiac risk factors such as elevated cholesterol or high blood pressure.
Heart scans is useful to whom?
In those who are in intermediate heart attack risk category, a heart scan may give information about heart attack risk. Based on risk factors, having a heart attack in the next 10 years falls somewhere between 10 and 20 %. For instance, if the patient is between ages 55 and 65 years and bordering on high cholesterol or blood pressure or a smoker, then a heart scan may be considered. As there is some evidence that people with calcium scores show risk of heart disease, many would be motivated to adopt lifestyle changes, lose weight or quit smoking than those who do not undergo heart scan.
Who do not benefit from heart scans?
If a person is younger than 55 years of age and has normal cholesterol and blood pressure levels, and does not smoke, heart attack percentage is calculated less than 10 % and falls under low-risk category. Probably, in such cases, a heart scan may not reveal anything more than what the doctor already knows.
A 20 % risk or greater risk of having a heart attack in the next 10 years means at high risk. If the person is older than age 65 with high cholesterol levels and high blood pressure and does smoke, then a heart scan will not do much good because the doctor knows the risk based on risk factors and the steps to prevent a heart attack such as taking medications and making significant changes in life style. If the person has already had a heart attack or a surgical procedure, then he is at a high risk of having a heart attack and therefore a heart scan will not provide any more information on how his/her condition should be treated.
Preparing for a heart scan
It is better to visit the doctor prior to the heart scan as this can provide additional information on the heart attack risk for a doctor to consider. The examination will include:
1. A review of the medical history and the patient's family medical history.
2. A physical examination including blood pressure.
3. A risk assessment including questions about exercise and smoking habits.
4. Blood tests including cholesterol levels.
5. The doctor has to be told if a woman is pregnant. This test is not done on pregnant woman.
Other than these, there are no special preparations to have before the heart scan.
The procedure and after
A coronary calcium scan is usually done by a radiology technologist. The pictures are interpreted by a radiologist. A team of family medical practitioner, internist, cardiologist or surgeon may also review this test. Heart calcium scans takes only a few seconds and during this procedure the patient is asked to hold their breath to obtain an accurate image. The scan shows the calcium in the heart arteries by using computerized tomography (CT).
Calcium deposits show up as bright white spots on the scan. The standard imaging technique for coronary arteries uses multi slice or helical CT. In addition to calcium, such scans also reveal the presence of any narrowing of heart arteries due to coronary artery disease. After the procedure there are no special precautions and the patient should be able to drive home and continue daily activities.
If calcium score is high, it means more aggressive treatment of heart attack risk factors should be done such as life style changes or medications. The doctor may recommend more invasive tests such as coronary Angiography based on scan results. Sometimes the result of the test may not be helpful if the patient has a fast heart rate or smokes.
Heart scans such as multi slice computerized tomography and helical CT are used to see calcium in arteries. Such type of scans expose the patient to radiation. There is a slight chance of developing cancer from having coronary calcium scan. The chance is higher in those who have had many radiation. It is imperative to consult with the doctor about the amount of radiation required for this test and confirm that the test is needed. Sometimes an allergic reaction to the medication that is used during the procedure is exhibited.
The results of such scans should never be interpreted alone but should be used with information about other overall heart health and any risk factors the patient may have such as family history and high cholesterol. It is possible to have false positive results. This means that the test shows a high chance of plaque in the arteries when it is not true. Those with low chance of heart disease are most likely to have a false-positive test.
Niemann pick is a type of lysosomal storage disease and is an inherited condition that involves the metabolism of lipids. This leads to a breakdown in the of use and transport of fats and cholesterol in the body. The disease affects the body's ability to mobilize fat within cells. When this fat (cholesterol and lipids) accumulates in large amounts, it causes dysfunction of the cell and untimely death of a person. Harmful levels of lipids accumulate in the spleen, lungs, liver, bone marrow and brain. Niemann pick disease is more common in children. The disease is classified into three major types namely Niemann pick A, B and C. Niemann pick Type A and Type B are caused by the deficiency in an enzyme called acid sphingomyelinase. This enzyme is found within the lysosome cells and is an essential component in metabolizing a lipid called sphingomyelin.
Symptoms are related to the type of disease.
Type A: occurs in children. Children may not survive as the condition affects the nervous system. Symptoms include:
Type B: occurs in childhood, known as the non-neurological type as the nervous system is not affected. Children survive into adulthood.
Type C: can occur in children or in adults
Other general symptoms include:
Diagnosis depends on the type of Niemann pick disease
For Type A or B: Blood sample or bone marrow sample is used to measure the level of acid sphingomyelinase in the blood.
For Type C: A small sample is skin is taken to test how the cells move and store cholesterol.
Other tests may include brain MRI, genetic testing and eye test to confirm if there is difficulty in normal eye movement
Cardiac Stress Test
A cardiac stress test aids in assessing how the heart can cope during exercise, especially when the body need for oxygen puts extra demands on the heart. A cardiac stress test is called a graded test or exercise tolerance test, exercise stress test or exercise electrocardiography. It helps to primarily evaluate the heart and vascular systems during the exercise. In fact, the American Heart Association has recommended the Cardiac stress test (EKG treadmill in particular) as the first choice to be tried on patients with medium risk of coronary heart disease and who exhibit certain risk factors of smoking, family history of coronary stenosis, high blood pressure, and high cholesterol.
The cardiac stress test can be done in a clinic or a hospital. The patient may be asked to exercise using a bicycle, treadmill or arm ergometer. The patient is attached to an ECG machine. The blood pressure cuff is placed on any one arm. The patient's heart is usually monitored using a 12 - lead EKG or ECG machine. A heart monitor may be used during and after exercise. After a baseline ECG is obtained, the patient begins to perform a low level of exercise, either by walking on a treadmill or pedaling on a stationary bicycle.
At each stage of the exercise, the pulse, the blood pressure and ECG are recorded along with any symptoms that the patient may be experiencing.
The level of exercise is gradually increased until the patient cannot keep up any longer because of fatigue or until symptoms like chest pain, shortness of breath or lightheadedness prevent further exercise. The goal of this stress test is to diagnose the presence or absence of coronary artery disease. In a sub maximal stress test, the patient exercises only until a pre-determined level of exercise is attained. These tests are used in patients with known coronary artery disease, to measure whether the patient can perform a specific level of exercise with relative safety.
The side effects of a cardiac stress test also include palpitation, chest pain, and shortness of breath, headache, nausea and fatigue. The hypertension caused by stress testing is always considered abnormal and it may lead to severe coronary disease. In stress tests, false positive results are not uncommon. There can be occasions when the patient's ECG changes could suggest ischemia, even in the absence of coronary artery disease. Similarly, in stress test, false negatives are also not uncommon. In some patients, no significant ECG changes will be seen even in the presence of coronary artery disease. Presently, a new concept called nuclear perfusion study is added to the stress test. This factor has helped to minimize the limitations and improve the diagnostic capability of stress tests.
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Bibliography / Reference
Collection of Pages - Last revised Date: October 20, 2019