Chronic stable angina- Causes – Symptoms – Tests – Treatment – Prognosis – Prevention

What is chronic stable angina?                                       
Angina pectoris or the pain in pectoral(chest)region of our body is the most common clinical manifestation of coronary artery disease, it results from an imbalance between heart(myocardial)oxygen supply and demand, most commonly resulting
from atherosclerotic coronary artery obstruction. Other major conditions that alter this balance and result in angina(pain) include aortic valve disease(diseases of aortic valves) , hypertrophic cardiomyopathy(diseases of cardiac muscles resulting in weakening and enlargement) , and coronary artery spasm(narrowing of coronary arteries which supply blood to heart muscles)

What are the symptoms?

Angina(pain) is typically associated with exercises,exertion or emotional upset and it is  relieved quickly by rest or drugs such as  nitroglycerin(GTN – kept under the tongue in need).

Major risk factors are cigarette smoking, hypertension, hypercholesterolemia (qLDL fraction;p HDL), diabetes, and family history of coronary artery disease  below age 55.

What are the physical examination findings?

Physical examination by a doctor is often normal.

But arterial bruits or retinal vascular abnormalities suggest generalized atherosclerosis.pathological fourth heart sound(S4) is common During acute anginal episode, other signs may appear  loud third heart sound(S3) or pathological fourth heart sound (S4), and a transient murmur of mitral regurgitation due to papillary muscle ischemia.

What are the Tests to detect chronic stable angina?

Mainly ECG (Electrocardiogram is used to detect and diagnose Chronic stable angina.It is a Non invasive test done by connecting few electrodes to your chest and recording electrical activity of the heart  there.there are many wave patterns identical to individual disease conditions of heart.

ECG May be normal between anginal episodes or may show old infarction. During angina, ST- and T-wave abnormalities
typically appear (ST-segment depression reflects subendocardial ischemia; STsegment
elevation may reflect acute infarction or transient coronary artery
spasm). Ventricular arrhythmias frequently accompany acute ischemia.

Stress ECG(Exercise ECG)

Sometimes heart needs stimulation by exercises to show some hidden abnormal electrical activities.it is done by stress ECG testing.
There Exercise is performed on treadmill or bicycle until target heart rate is achieved or patient becomes
symptomatic (chest pain, light-headedness, hypotension, marked dyspnea(Breathlessness), ventricular
tachycardia) or develops diagnostic ST-segment changes. From this test useful information achieved
includes duration of exercise achieved, peak heart rate and Blood pressure, depth,
morphology, and persistence of ST-segment depression and whether and at
which level of exercise pain, hypotension, or ventricular arrhythmias develop.
Note: Exercise testing should not be performed in patients with acute Myocardial infarction(Heart attacks), unstable angina, or severe aortic stenosis.

If the patient is unable to exercise, intravenous dipyridamole (or adenosine) testing can be performed.There are many chemicals used to stimulate hidden diseases of heart and by that visualizing  abnormal electrical activities of heart.

There are Some patients who do not experience chest pain during ischemic episodes with exertion(“silent ischemia”) but are identifed by transient ST-T-wave abnormalities during stress testing or Holter monitoring (Holter monitoring is a portable small monitor is attached to your body for 24 hours and it records the electrical activity of heart for that 24 hours)

Coronary Arteriography is the definitive test for assessing severity of  coronary artery disease.
major indications for doing a Coronary Arteriography are,

(1) angina refractory to medical therapy.

(2) markedly positive exercise test (2-mm ST-segment depression or hypotension with exercise)suggestive of left main or three-vessel disease.

(3) recurrent angina or positive exercise test after MI.

(4) to assess for coronary artery spasm.

(5)to evaluate pts with perplexing chest pain in whom nonivasive tests are not diagnostic.

what are the treatment options available?
General
• Identify and treat risk factors: mandatory cessation of smoking; treatment
of diabetes, hypertension, and lipid disorders.
• Correct exacerbating factors contributing to angina: marked obesity,anemia, hyperthyroidism.
• Reassurance and patient education.

Long-Term Angina Suppression
Three classes of drugs are used, frequently in combination

1.Long acting nitrates.

2.Beta blockers.

3.Calcium channel antagonists(inhibitors)

Long acting nitrates

May be administered by many routes such as sublingual(under the tongue),Intravenous,oral etc.

started at the lowest dose and frequency to limit tolerance and side effects
of headache, light-headedness, tachycardia.

SHORT-ACTING AGENTS

Sublingual TNG  0.3–0.6 mg   As needed
Aerosol TNG  0.4 mg (1 inhalation)   As needed
Sublingual ISDN  2.5–10 mg    As needed

LONG-ACTING AGENTS

1.ISDN

Oral  5–30 mg  tid
Sustained-action 40 mg bid (once in A.M., then 7 h later)
TNG ointment (2%) 0.5–2 qid (with one 7- to 10-h nitrate-free interval)
TNG skin patches 0.1–0.6 mg/h Apply in morning, remove at bedtime

2.ISMO
Oral 20–40 mg bid (once in A.M., then 7 h later)
Sustained-action 30–240 mg qd

Note: TNG, nitroglycerin; ISDN, isosorbide dinitrate; ISMO, isosorbide mononitrate.

Beta Blockers

eg-atenelol,propranolol

All have antianginal properties.
selective agents are less likely to exacerbate airway or peripheral vascular disease. Dosage should be titrated to resting heart rate of 50–60 beats/min.Contraindications to beta blockers include CHF, AV block, bronchospasm,“brittle” diabetes. Side effects includefatigue, bronchospasm, depressed Left Ventricular function, impotence, depression, and masking of hypoglycemia in diabetics.

Indications – Angina,After myocardial infarct,Tachyarrhythmias

Contraindications – Asthma and COPD(chronic obstructive pulmonary diseases).Heart blocks

Calcium channel Antagonists

Useful for stable and unstable angina, as well coronary vasospasm. Combination with other antianginal agents is beneficial, but verapamil should be administered very cautiously or not at all to patients on beta blockers or disopyramide (additive effects on Left Ventricular dysfunction). Use sustained-release, not short-acting, calcium antagonists; the latter increase coronary mortality.

Aspirin

80–325 mg/d reduces the incidence of MI in chronic stable angina, following MI, and in asymptomatic men. It is recommended in patients with coronary artery disease (CAD) in the absence of contraindications (GI bleeding or allergy) Consider clopidogrel (75 mg/d) for aspirin-intolerant individuals.

Mechanical Revascularization

Percutaneous Coronary Intervention (PCI) Includes percutaneous transluminal angioplasty (PTCA) and/or stenting. Performed on anatomically suitable stenoses of native vessels and bypass grafts.

It is more effective than medical therapy for relief of angina. Has not been shown to reduce risk of MI or death.It should not be performed on asymptomatic or only mildly symptomatic individuals. With PCI initial relief of angina occurs in 95% of pts. however,
with PTCA stenosis recurs in 30–45% within 6 months (more commonly in patientsts with initial unstable angina, incomplete dilation, diabetes, or stenoses containing thrombi). Restenosis is reduced to 5–10% with drug-eluting stents. If restenosis occurs, PTCA can be repeated with success and risks like original procedure. Potential complications include dissection or thrombosis of the vessel and uncontrolled ischemia or CHF. Complications are most likely to occur in pts with CHF, long eccentric stenoses, calcified plaque, female gender, and dilation of an artery that perfuses a large segment of myocardium with inadequate collaterals. Placement of an intracoronary stent in suitable pts reduces the restenosis rate to 10–30% at 6 months. PCI has also been successful in some
patients with recent total coronary occlusion (3 months).

Coronary Artery Bypass Surgery (CABG)

For angina refractory to medical therapy or when the latter is not tolerated (and when lesions are not
amenable to PCI) or if severe CAD is present (left main, three-vessel disease with impaired LV function). CABG is preferred over PTCA in diabetics with coronary artery disease (CAD) in 2 vessels because of better survival.

The relative advantages of PCD and CABG 

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