Angina pectoris

1.0 Summary

Angina pectoris is the chest discomfort which occurs when the heart muscle could not received sufficient oxygenated blood. It is due to atherosclerosis which is the buildup of the plaque at the coronary arteries that reduce the flow of blood to the heart. Also, angina can leads a patient to heart disease such as coronary artery disease (CAD) or myocardial infection (MI). There are three kinds of angina which is the stable angina, unstable angina and variant angina and each of them are different from their signs and symptoms and treatments. Angina is diagnosed based on medical and family history, physical examination and test such as electrocardiogram (ECG) and coronary angiography. However, the patients’ conditions will determine which methods need to be used in order to cure angina. Lastly, pharmacists play an important role besides doctors in treating the angina patients.

2.0 Introduction

Angina pectoris is the medical term for chest pain or discomfort which is a common symptom indicating the sign of heart diseases, for example, coronary heart disease (CHD). The pain is caused by the insufficient of oxygen rich blood supply to the heart muscle which leads to cardiac ischaemia.1 Other than that, the cause is due to the build up of plaque called atherosclerosis which is the gradual buildup of fatty deposits and blocks several coronary arteries. As a result, the heart could not receive blood supply as the coronary arteries become narrow and stiff and this minimizes the oxygen supply to the heart.1, 2

Besides that, angina can be categorized into four different types of categories such as stable angina, unstable angina and variant angina. There are differences in these four types of angina such as signs and symptoms therefore, they required specialized treatments. For example, stable angina is very common compare to variant angina. Other than that, doctors will do some physical exam or examines the patients’ histories in order to diagnose whether they are in the risk of getting angina and they will uses several methods such as the exercise electrocardiogram (ECG), radioisotope scan and coronary angiography. After that, doctors will determine whether which treatment such as surgeryor medication is needed to treat the patients. However, the patients cannot recover if they didn’t change their lifestyles and follow the doctors’ advices.

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2.1 Signs and Symptoms

People who are diagnosed with angina pectoris will often express the feeling of tightness, pressure, squeezing and burning in or around the chest. The patients will have an attack such as the central chest pain which may spread to the arms, neck, jaw, throat, back or upper abdomen. Also, they may also encounter shortness of breath during physical activity and follow by nausea, fatigue, sweating, light-headedness, or weakness. However, not all chest discomfort is angina and sometimes it is caused by acid reflux (heart burn) and lung infection or inflammation. Also, the signs and symptoms are vary depends on the type of angina.

2.2 When does angina occur?

As it was stated, angina occurs when there is an increase in the demand of oxygenated blood to the heart. Most of the time, angina occurs when the patients are doing some vigorous exercises or physical activities such as climbing hill or carrying heavy groceries. At the same time, it will occurs when the patients experiencing emotional stress, digesting heavy metal and at extreme temperature. The patients who were diagnosed with variant angina could get angina attack even when they are resting.

2.3 Causes of Angina

Coronary arteries are the arteries which deliver oxygenate blood to the heart muscle in order to keep the heart pumping. However, when the heart could not receive adequate amount of blood, it can causes angina attack. There are three important coronary arteries, left anterior descending artery, left circumflex artery and right coronary artery in heart which can causes angina when one of them are blocked.7 This situation reflects the symptom of coronary arteries diseases (CAD) where the arteries are narrowed down due to the buildup of plaque on the inner walls of the arteries. Also, the buildup of plaque can cause the blood clot to form and block the arteries.2, 7

Figure 2 shows the differences between a normal and healthy artery and a block artery. Blood flows easily along the healthy arteries to the heart and the heart muscles can function normally without any interruption. However, this scene can’t be seen in block arteries. Coronary arteries diseases (CAD) occurs when one of the important arteries are narrowed by the plaque and angina could be felt as the arteries are having a hard time in supplying oxygenated blood to the heart. Also, blood maybe clot at the blocked arteries and stop the blood from flowing to the heart, when this happens, patients will face myocardial infection (MI).

Besides that, atherosclerosis could be cause by high level of cholesterol in blood, smoking, obesity, diabetes mellitus and alcohol. Smoking boosts atherosclerosis by maximized blood pressure and heart rate which induce the heart to demand for more myocardial oxygen. It lowers the oxygen-carrying capacity and increases the recurrence of angina.

3.0 Classification

3.1 Stable Angina

Stable angina can be described as the frequency, duration or precipitating causes remain unchanged in the past 60 days and it is the most common type of angina.3 The attack last for about 10 minutes or less than that and can be relieved by resting or medication. Hence, patients who are diagnosed with stable angina will experience episode of chest discomfort which will spreads to the arms, back, or other areas that is usually predictable. The stimulus which will maximize the myocardial oxygen demand will induces stable angina by increasing the heart rate or blood pressure of the patients.5 During physical activity, sympathetic nervous system will be activated and causes increase of the heart rate, blood pressure and contraction demanding more oxygen. When the oxygen demand is more than the heart is able to supply, chest discomfort maybe be felt and this reflects the presents of MI.4 Also, several arteries which are narrowed down due to the buildup of plaque is one of the factors.

3.2 Unstable Angina

Unstable angina is more dangerous than stable angina as it is an acute coronary syndrome and should be treated as emergency and be evaluated in the hospital carefully. Also, it does not follow a pattern can happen without any physical exertion.2, 3 Patients will experience an unexpected pain or discomfort which last longer and does not relieve by rest or medication. This scenario is causes by the narrowing of the coronary arteries by atherosclerosis. However, blood clots are the major factors which contribute to the blockage of the arteries. If the plaque ruptures, blood clot may form and block the arteries as the blood clot can divide into larger clot which can cause heart attack.2 Chest discomfort can attack each time the blood is clot when the clots slightly dissolve which will later reform again. Besides that, patients will be in the risk of myocardial ischemia, severe cardiac arrhythmias or even sudden dead.6

3.3 Variant Angina

Variant angina also known as Prinzmetal’s angina is due to the coronary artery spasm which causes the artery walls to tighten and narrow.2, 3, 6 As a result, it reduces the flow of the blood to the heart and thus, causing chest discomfort. Usually, variant angina happens during the night or early hours when a patient is at rest because of the momentary reduction of the coronary oxygen supply rather than the increase of myocardial oxygen demand.2 It may occur in a person with or without CAD as the spasms in at artery can be cause by exposure to the cold weather, emotional stress, medication which causes vasoconstriction, smoking and the use of cocaine.2

4.0 Diagnose

If a person is having the angina symptoms, he or she should consult their doctor in order to find out more about their complication. Doctors, who are in duty will conducts a physical exam on the patients, ask about the symptoms and get to know the risk factors and the family history of CAD or other heart disease. Other than that, doctors also will conduct some of the following test in order to diagnose angina.

4.1 Exercise Electrocardiogram (ECG)

ECG is one of the most widely used tests which measure the rate and regularity of the heartbeat.2, 5 It records the rhythm and electrical activity of the heart and thus, indicating the severity of coronary artery diseases. The patients will exercises on a treadmill while doing the ECG test since angina occurs during physical activities. ECG will show an abnormal reading if the patients have narrowing coronary arteries. However, some people with angina also have a normal ECG readings and therefore, exercise stress testing is carried out.

4.2 Coronary Angiography

It is a blood vessels or heart chambers examination using X-ray and it is tested during catheterization. A catheter (fine, hollow tube) will be placed into an artery in the patient’s forearm or groin and advance it till it reaches the coronary artery. Next, a dye which can be detected by X-ray will injected into the coronary artery and several pictures will be obtained. These pictures are called angiograms and it is helpful for the doctors to observe which arteries are narrowed or blocked.6

4.3 Radioisotope scan

It is also known as radionuclide scan which emits gamma rays. A small amount of radioactive isotope will be injected into the vein while the patients exercise. Then, the gamma rays will be detected by the gamma camera which will be placed close to the chest in order to detect which parts of the heart muscles are blocked.9

5.0 Treatment

The primary cause for angina is lack of oxygen supply which cannot meet the demand of the heart. Therefore, the treatment for angina is to make sure that the heart will receives sufficient oxygen by balancing the oxygen demand and supply. There are few ways of treatment which include medication, surgery and changing the patients’ lifestyle.

5.1 Medical treatment

5.1.1 Nitrates

Nitrates are the most popular used medicines to treat angina as it open up the blood vessels and widens the coronary arteries (vasodilation), which allow more blood to flow to the heart muscles and reduce the work of the heart.5 It plays the same effects of the endogenous nitrous oxide which result in the powerful vasodilating effects.1 Nitrates act by dilating the coronary arteries and peripheral circulation, increase the myocardial oxygen supply by maximized the coronary flow and lower the left ventricular blood pressure. Other than that, it can improve exercise tolerance in order to prolong the angina occurring by preventing coronary spasm and coronary arterial vasoconstriction caused by exercise.1, 6 Usually, sublingual nitroglycerin (GTN) tablets or spray are used to prevent ischemia before any exercise as it can quickly absorbed into the buccal mucosa to provide a relief within 3 minutes.5 Besides that, long-term nitrates for regular oral administration such as isosorbide mononitrate are common practice among the patients. Although nitrates are non-toxic and well tolerated, it can cause headache, flushing and postural dizziness.5

5.1.2 Beta-blockers

Patients who are diagnosed with angina but not contraindications will take beta-blockers as the first-line therapy.5 Beta-blockers act by reducing the rate and force of cardiac contraction, arterial blood pressure, and myocardial oxygen demand of the heart during physical activities and improve coronary perfusion during diastole. Other than that, there is an increase in survival rate of patients with MI who are taking beta-blockers. However, patients who have the history of bronchial asthma should not be prescribed with beta-blockers as they tend to increase coronary vasospasm due to unopposed alpha-agonist activity.3 There are a few of approved beta-blockers which are water-soluble and are used to treat angina such as perpanolol, metaprolol, atenolol, nadolol and timolol. Since they are water-soluble, it is less likely they will enter the brain and cause central adverse effects. Besides that, beta-blockers also cause side effects such as bradycardia and hypotension, lethargy, fatigue and impotence.11

5.1.3 Calcium Channel Blockers

Calcium channel blockers perform the same effects of nitrates as vasodilators and boost myocardial oxygen balance on coronary flow and blood pressure. They relieve angina and extend the exercise time to onset of angina. Calcium channel blockers inhibit calcium ions from flowing into the cells through open calcium channel and mediate the contraction of cardiac muscles. There are two types of calcium channel blockers, dihydropyridines such as nifedipine, amlodipine and felodipine and non-dihydropyridines such as diltiazen and verapamil. They act on the peripheral vasodilation, coronary vasodilation and lower the rate and force of cardiac contraction. On the other hand, patients who are suffering from heart failure should avoid varapamil and diltiazen as they cause negative inotrophic action. Other side effects of calcium channel blockers are facial flushing, headache, postural dizziness, mind ankle oedema and constipation.2

5.1.4 Antiplatelets

Platelets are important in blood clotting and play a role in the pathogenesis of atherosclerosis. Also, it can blocks the coronary arteries and causes the heart muscles from getting sufficient oxygenated blood. Therefore, antiplatelet drugs such as aspirin are use in reducing the risk of death or nonfatal MI for patients with unstable angina. They can minimize the platelet aggregation by irreversible inhibiting the platelet enzyme cyocooxygenase-1 which prevents thrombaxane A2 formation.11

5.2 Surgery

Doctors will advise the patients to undergo coronary angioplasty or coronary bypass surgery if they cannot relieved by any medication or it is life threatening.

5.2.1 Coronary Angioplasty

This is a treatment which opens blocked arteries and improves blood flow to the heart muscle, reduce chest pain and prevent heart attack. Before the doctors perform coronary angioplasty on the patients, they will do an angiogram and take an X-ray picture of the patients’ arteries. A catheter with a terminal balloon is introduced into an artery at the patients’ groin or arm. X-ray screening directs the catheter until it reaches the blocked arteries and few pictures are taken. Then, the balloon will be inflated to push the fatty tissues outward against the artery wall. A ‘stent’ which is a small stainless mesh tube will be placed at the newly opened arteries as it can hold up the arteries and decrease the arteries from narrowed down.2, 3 Figure 3 shows the clogged artery before and after the surgery.

5.2.3 Coronary Bypass Surgery

It is the most common type of heart surgery and it has cures at least 240,000 patients in United States each year. It diverts blood around blocked arteries in the heart by attaching a vein from the leg or artery from the chest or another part of the body between the aorta and the blocked area. As a result, it creates a new route for the blood to flow to the heart and the heart muscle will receive the oxygenated blood. Increasingly, the left internal mammary artery is being used as the grafting blood vessel since it results in a better long-term result and less likely to narrow over the time compare to veins.3 Before the surgery, the patients will undergo coronary angiography to locate the narrowed arteries, have an electrocardiogram, blood test, urine test and chest X-ray to provide the latest health information for the doctors in charged. During the process, the heart of a patient will be arrested and the breastbone will be divided while the blood is send through a heart-lung machine. After the surgery, there will be scars left on the patients and they may feel chest discomfort which will tone down over time.10

5.3 Lifestyle Changes

A patient will not recovers from angina if he or she did not change his or her lifestyle after taking medication or surgery as it plays a major role in their life. By changing their lifestyles, patients can avoid the symptom of angina and improve their heart health. For example, patients should adapt a healthy diet which is full of vegetables and fruits and quit smoking. Also, patients who are obese should try to lose their weight until it reaches the BMI (Body Mass Index) scale. Other than that, they should exercise regularly as directed by the doctors.

However, the most important things are to avoid bringing on an episode of angina such as taking a break or rest when the angina comes on with exertion. Also, the patients need to avoid taking a large amount of food at a time after a heavy meal. Finally, patients need to learn how to distress when they facing difficulties as it will causes the angina to attack.

6.0 Clinical Scenario

6.1 Clinical Scenario 1

Aspirin is an antiplatelet drug which is to prevent the aggregation of platelets and thus, reduce the risk of atherosclerosis. 75mg of aspirin is prescribed to the old man is adequate to prevent the thromboxane A2 production and it is the initial dose given for long term treatment.11 Since aspirin is an acetylsalicylic acid, the old man should take the tablets in the morning after food in order to reduce the stomachache irritation. Patients who are diagnosed with asthma, pregnancy, haemophilia, hypertension and other bleeding disorders should avoid taking aspirins.

Atenolol is a β1 blocker which treats angina by inhibiting the sympathetic nervous system. It lowers the heart rate and blood pressure, reduces the intake of oxygen and so, minimizes the frequency of angina. 100mg of atenolol is recommended daily in the morning because the blood pressure is at lowest level and thus, it can maintains the blood pressure.3 Atenolol should be keeps away from the light and heat and stored in a tightly sealed container. Doctors should explain to the patients about the side effects of the drug such as dizziness, fatigue and sexual dysfunction. However, patients cannot stop the medication as sudden withdrawal of atenolol may cause exacerbation of angina.11

GTN (glyceryl trinitrate) spray is an aerosol spray which is used to dilate and widen the walls of coronary arteries and increase the flow of blood to the heart.3 It is a common and most effective drug to ease angina as it provides a rapid relief of angina. Therefore, the patients should always carry the spray with them at all time. It should be used before the patients engaging any physical activities like climbing stairs which might lead to an acute attack of angina. The side effects of GTN spray are throbbing headache, flushing, nausea and dizziness.11

6.2 Clinical Scenario 2

In scenario 2, the functions of aspirin are been described in scenario 1 but the dosage given to this lady is lower than in scenario 1. The prescription was given based on the decrease in bodyweight, total body water and mass. It is important to give a maximum level of absorption, distribution, metabolism and excretion of medication in elderly patients with fewer side effects.

Imdur, which contains isosorbite mononitrate is used to prevent the onset of angina. Nitrates are powerful vasodilators which minimizes the workload of the heart which leads to a decease in the myocardial oxygen demand. In this case, Imdur is given instead of beta-blocker because beta-blocker will reduce a patient’s heart rate and blood pressure which may lead to heart failure and therefore, it is not suitable for this lady with a history of congestive heart failure. Also, a dosage of 60mg Imdur is adequate and should taken once in the morning because the duration of its action can be up to 12 hours and to reduce the development of tolerance with respect to anti-angina effect.3, 11

Lastly, GTN tablets were prescribed instead of spray in order to provide relieve for angina. It has the same effects as GTN spray and it is administered under the tongue and being absorbed while the tablet dissolves when the pain develops. A dose is able to provide relief within a minute. The side effects of GTN tablets are the same as the spray.

7.0 Role of Pharmacist

Doctors play a very important role in curing the patients who are diagnosed with heart attack and other diseases. However, the process is not complete without pharmacists because they are the people, who are well known for their responsibilities in prescribing medicines for the patients. Also, pharmacists also educate the public about angina by deliver the messages to the patients, making sure the patients understand about their condition and helping them to combat angina. So, an effective communication skill is needed in order to council the patients on their medication without any mistakes.

There are some people who are not aware that they are suffering from angina due to the lack of knowledge about angina. As a result, some of them will simply prescribe themselves with painkiller or any medicines which can relief their chest pain without knowing about the dangerous of their condition. Thus, the pharmacists are responsible to deliver the information about angina to create awareness in the public. The information about the signs and symptoms can surely help the public to aware about their health and to go for a medical check up and seek treatment.

Every patient are different and therefore, it is important that they are treated differently based on their condition, sex, age and existing condition such as hypertension, congestive heart failure and diabetes. This is because different conditions need different kind of medications in order to avoid any complications. For example, a patient who had heart failure and suffers from angina should not be prescribed with beta-blocker as beta-blocker will worsen the patient condition.

Other than that, pharmacists should advise the patients on when and how to take the medication, the dosage of medication and how to keep the medication. This is crucial as a simple mistake can lead the patients to death such as overdose. Also, the pharmacists will advise the patients on what to avoid and how to take care of themselves so that they can faster recover from angina. For example, the pharmacists will advise them that they should avoid any vigorous activities and watch their diets.

Lastly, a pharmacist should keep his/her patients’ conditions private and confidential as this is the trust which his/her patient had given them. Also, it can help the pharmacist to monitor the condition of their patients and to make sure that they will benefit most on the drug prescribed with the least side effects.

8.0 Conclusion

As been described, angina is not a disease but a symptom indicating heart disease. It required a long term treatment in order to prevent angina from recurrence and should be taken seriously. So, the role of pharmacist is very essential by helping the patients in managing their life and educating them on angina in order to lead them to healthier life.

9.0 References

1. Williams, H. & Stevens, M. (2002) Chronic stable angina. Pharm.J.. 269:363-365
2. National Heart Lung and Blood Institute, Disease and Condition Index. Angina.
3. Khan, M.G., Topol, E.J., Saksena, S. & Goodwin, J.F. (1996) Heart Disease Diagnosis and Therapy, A Practical Approach. William & Wilkins, Baltimore. Pages 133-183.
4. Lily L. S. Pathophysiology of Heart Disease: A Collaborative Project of Medical Student & Faculty. 3rd Edition (2203) Lippincott. William & Wilkins.
5. Timmis A. D. and Nathan A. W. (1997) Essential of Cardiology. 3rd Edition.
6. American Heart Association, Fighting Heart Disease and Stroke. Angina.
7. eHealthMD, Angina Pectoris. http://www.ehealthmd.com Accessed 28 Aug 2007.
8. iVillage Total Health, Angina. http://heart.health.ivillage.com Accessed 29 Aug
9. Patient UK, Radionuclide (Isotope) Scan. http://www.patient.co.uk
10. Texas Heart Institute, Coronary Artery Bypass. http://texasheart.org
11. British Medical Association and Royal Pharmaceutical Society of Great Britain. British National Formulary 43, March 2002. 2.4 Beta-adrenoceptor blocking drugs, 2.6.1 Nitrates, 2.6.2 Calcium-channel blockers and 2.9 Antiplatelet drugs.