| ID | 68 |
|---|---|
| Name | STABLE ANGINA PECTORIS |
| Cause | |
| Signs Symptoms | |
| Diagnosis | D. Diagnosis: 1. Musculoskeletal pain 2. Peptic ulcer pain 3. Pericardial pain 4. Oesophageal pain |
| Investigations | Investigations: 1. ECG Resting ECG- may show normal in most cases; there may be evidence of old myocardial infarction (pathological or deep Q wave); left ventricular hypertrophy or left bundle branch block. ECG during attack- transient ST depression, T inversion or upright T wave may appear. 2. Exercise ECG or ETT (exercise tolerance test)- it is very useful in confirming the diagnosis of angina, assessing the severity of coronary artery disease, identifying the high-risk individuals & to evaluate responses to therapy. • A normal or negative exercise test does not exclude coronary artery disease (false-negative test). • Upto 20% of cases with positive exercise test may have no coronary artery disease (so-called false-positive test) 3. Echocardiography- to assess ventricular wall involvement and ventricular function. 4. Coronary angiography- it is an invasive & risky procedure, and done only when the benefit outweights the risk of procedure, (mortality rate less than 1 in 1000 cases). Indications for angiograpfy: i. Usually done with a therapeutic view to coronary bypass grafting or angioplasty. ii. In some cases diagnostic angiography is indicated when non-invasive tests failed to identify the exact cause, iii. Angina refractory to medical therapy, iv. Unstable angina v. Patients under 50 years with angina or myocardial infarction. 5. Cardiac scintigraphy (Isotope scanning)- it is a myocardial perfusion scanning test done by using i.v administration of radioactive isotope (such as Isotope thallium 99 Rubedium)- this is useful in the cases, where the patient is unable to exercise or the exercise test is uninterpretable. Its diagnostic accuracy is higher than that of exercise ECG. |
| Management | Management:1,2 A. Treatment of anginal pain: To relieve from acute anginal attack and to prevent further attack five groups of drugs are commonly used- i. nitrates, ii.b-blockers, iii. calcium channel blockers, iv. potassium channel activators, v. I.channel antagonist. A new antianginal drug has been approved y the FDA as the first-line drug for chronic angina. 1. Nitrates: During attack: Sublingual glyceryl trinitrate (GTN): Glyceryl trinitrate is the drug of choice during acute attack; it should be administered as a buccal spray ( Sublingual) from a metered dose aerosol (400umg/ spray) or as a tablet (0.3-0.5mg) placed under the tongue immediately; pain usually relieves within 2-3 minutes. In case of tablet, patient should be instructed to spit it out once the angina is relieved. If anginal pain not relieved even with 3 tablets or lasts more than 20 minutes, may be the indication of infarction, and patient should be immediately transferred to the specialized hospital in C.C Unit. Side-effects of GTN include, headache, hypotension or rarely syncope/Flushing. Prevention of further attacks: Prophylactic nitroglycerin: Gglyceryl trinitrate also can be used sublingually as 0.3-0.6mg tablet or as buccal spray about 5 minutes before any physical activity or exertion likely to precipitate angina. Isosorbide dinitrate (2.5-10mg) may also be used alternatively (slightly longer-acting). Long-acting nitrates: Long acting nitrate preparations are useful in the long-term treatment of chronic stable angina, i. Isosorbide mononitrate (active metabolite of dinitrate, and has more consistent bioavailability), 10-40mg orally twice daily or 60-120mg once daily in a sustained release preparation. Or, ii. Isosorbide dinitrate, 10-40mg orally 2-3 times daily. The chronic nitrate therapy may cause development of some degree of tolerance in most of the patients. Side-effects include, headache, nausea, dizziness, hypotension etc. 2. b-blockers: b-blockers help in angina by reducing myocardial oxygen consumption by lowering heart rate, .blood pressure and myocardial contractility specially during exertion. So, they are also the drug of choice in old myocardial infarction, as their benefit is proved in secondary prevention. i. Atenolol 50-100mg daily orally (commonly prescribed). Or, ii. Metoprolol 50-100mg twice daily (often advised in patients with impaired renal function). N.B: B-blockers should not be withdrawn abruptly as it may precipitate dangerous arrhythmias, worsening angina, or myocardial infarction (beta-blocker withdrawal syndrome). 3. Calcium channel blockers: These also prevent angina by reducing myocardial oxygen demand by lowering blood pressure and myocardial contraction force leads to vasodilatation • Nifedipine, nicardipine or amlodipine- these are very effective drugs, but as they often cause a reflex tachycardia, they are best advised in combination with a b-blocker. • In contrast, verapamil & diltiazem tend to cause bradycardia (as they inhibit conduction through the AV node). So, they are usually suitable in patients, who are not receiving b-blockers. 4. Potassium channel blockers:2 Nicorandil is the only drug in this class currently available for clinical use. Usual dose is 10-30mg orally every 12 hours. Potassium channel blockers work by dilating arterial and venous system and unlike nitrates these do not exhibit any tolerance. 5. I, channel antagonist:2 Ivabradine is the first drug of this class. It induces bradycardia by modulating ion channels in the sinus node. Unlike beta & calcium channel blockers it does not have other cardiovascular effects, therefore, it is safe to use in patients with heart failure. 6. Ranolazine:1 Drug for chronic stable angina is ranolazine. It decreases the late sodium current and thereby decreases intracellular calcium overload. It has no effect on heart rate and blood pressure. It prolongs exercise duration and time to angina, while given alone or given with other antianginal drugs. Treatment policy: The present treatment policy of acute attack is to start with sublingual glyceryl trinitrate (GTN) to progress to a B-blocker unless there is any contraindication and then to add nifedipine or amlodipine or a long-acting nitrate, such as isosorbide mononitrate. B. Treatment of aggravating factors: If there is any aggravating factor, such as tachyarrhythmia, hypertension, left ventricular failure, emotional state, should be treated & controlled immediately. C. Anti-platelet drugs: Aspirin- a low-dose aspirin preparation (75-150mg) should be advised for all patients with coronary artery disease for indefinite time, unless there is any intolerable side-effect. Or, Clopidogrel, an antiplatelet drug, 75mg daily may be given as an alternative of aspirin. D. Lipid-lowering drugs: These drugs are used in coronary heart disease, to lower the LDL cholesterol level to 100mg/dl, which markedly improves the angina and also reduces the coronary events in future. Commonly used drugs are statins (e.g atorvastatin) and fibrates (e.g gemfibrozil). (For dosages- see in the therapeutic section). E. Surgical treatment: Indications’: i. When medical therapy fails to control angina to its tolerable limit, ii. Patient with left main coronary artery stenosis more than 50% affected with or without symptoms, iii. Patient with two or three-vessels disease with left ventricular dysfunction, iv. Patients with unstable angina, controlled with medical therapy, continue to show ischaemia on exercise test, v. Post-myocardial infarction patients with continuing angina or severe ischaemia on non-invassive testing. Types of procedures: i. Coronary Artery Bypass Grafting (CABG): In this procedure, bypass grafting operation of major coronary artery stenoses are done by using grafts from the internal mammary arteries or reversed segments of the patients own saphenous vein. In general the operative mortality is less thanl%. ii. Percutaneous Transluminal Coronary Angioplasty (PTCA): Coronary angioplasty is performed by passing a fine guide-wire through stenosed coronary vessel under radiographic control and placing a balloon and then inflated to dilate the stenosis. iii. Devices for percutaneous coronary interventions: There are some new atherectomy devices have been developed to remove plaques from coronary arteries and vein grafts. F. Advice: 1. Do not smoke. 2. Maintain an ideal body weight & a low level of body LDL cholesterol (100mg/dl). 3. Take regular exercise, up to, but not beyond point of chest pain is beneficial. 4. Avoid severe unaccustomed exertion, vigorous exercise after a heavy meal, or avoid very cold weather. |
| Introduction | Stable angina, also known as classical or exertional angina, is the commonest type of angina, characterized typically by central chest pain, provoked by physical exertion, aggravated by anger or excitement and usually relieved by rest (within minutes). Factors precipitating angina: 1. Physical exertion 2. Cold exposure 3. Heavy meals 4. Intense emotion 5. Violent dreams 6. Lying flat (decubitus angina) |
| History | |
| Etiology | |
| Clinical Features | Clinical feature: 1. Pain: a. Location: Central chest pain specially at mid or upper sternal region, sometimes may be felt over the left side of the chest. b. Character: The pain is generally described as heavy, tight or constricting, squeezing, pressing or crushing in character, ‘like a band round the chest’. The intensity of angina can range from a mild ache to a very severe pain, that provoking sweating & fear. Breathlessness, sometimes a prominent feature. c. Radiation: Pain may radiate to the neck, jaw, shoulders & upper arms, commonly on the left side. It may also extend up to elbow, wrist or even fingers. d. Provoking factors: Angina may start even at rest, but there may be some provoking factors e.g exercise, walking uphill or upstairs, after heavy meals, exposure to cold weather, emotional upsets or even during sexual intercourse. e. Disappearance: It may disappear after taking rest for a while or after taking nitroglycerine. f. Duration: Angina, generally lasts for short duration. If the attack is provoked by physical exertion, it usually relieved by rest within a few minutes (not more than 2-5 minutes). If the attack is following a heavy meal and aggravated by anger or excitement, often last 15-20 minutes. Attacks lasting more than 30 minutes are unusual and suggest the development of unstable angina or myocardial imfarction. 2. On examination: Patient may look pale & anxious, motionless & still, pulse rate increased, systolic blood pressure may be slightly elevated/decreased. Aortic second sound may be accentuated. Atrial sound may be palpable & audible; this may give rise to a gallop rhythm. Grading of Angina:3 Grade I When ordinary physical activities do not cause angina (only angina provoked by heavy physical work) Grade II Slight limitations of ordinary physical activities (such as walking uphill provoking, angina) Grade III Marked limitation of ordinary physical activities (such as walking on the level provoking angina) Grade IV Inability to carry on any physical activity (i.e angina may occur even at rest) ( Courtesy: Following ‘Canadian Cardiovascular Society grading of angina of effort’) |
| Preventions | F. Advice: 1. Do not smoke. 2. Maintain an ideal body weight & a low level of body LDL cholesterol (100mg/dl). 3. Take regular exercise, up to, but not beyond point of chest pain is beneficial. 4. Avoid severe unaccustomed exertion, vigorous exercise after a heavy meal, or avoid very cold weather |
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