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Angina Pectoris |
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Symptoms
Variants
Investigations
TreatmentGeneral
Medical
Surgical
Prognosis
Angina
·
Diagnosis is largely based on the clinical history. ·
Patient describes chest pain as “heavy” or “tight”. It can range
from a mild ache to a very severe pain that provokes sweating and anxiety. ·
Typically the pain is central / retrosternal and may radiate to the jaw
or arms. It may be associated with breathlessness and faitness. ·
Classically it is precipitated by physical exertion, cold weather, heavy
meals and extremes of emotion. ·
Normally the pain regresses quickly when the patient rests. ·
Usually there are no abnormal findings in examination although evidence
of risk factors may be present. Investigations
·
As a standard ECG is often normal when these patients are at rest, an
exercise ECG is usually performed. ·
During the exercise ECG, ST segment depression suggests myocardial
ischaemia, particularly if it is associated with typical chest pain. ·
Other investigations include cardiac pharmacological stressing and
scintigraphy, echocardiography and coronary angiography. Unstable Angina
·
Unstable angina is similar to exertional angina described above but it
must be of recent onset, getting worse or occurring at rest to warrant this
definition. ·
If untreated it will progress to myocardial infarction in over 10% of
cases. Investigations
·
Standard ECG ·
Unstable angina is an indication for coronary angiography, which would
not normally be performed in stable angina. Treatment Of Angina
Inform the patient as to the nature of their condition, and reassure
them that in general the prognosis is good. Treat underlying problems such as
anaemia or hyperthyroidism, management of diabetes and hypertension should be
optimised. Risk factors already mentioned should be identified and steps taken to
correct them. e.g. stopping smoking, treating hypercholesterolaemia. Exercise
should be encouraged, and weight loss where appropriate. The choice between medical therapy and revascularization (coronary
artery by grafting and angioplasty) is difficult and depends on a number of
factors including symptoms, angiographic anatomy and patient choice. Treatment
options should be considered complementary. As mentioned earlier there is good evidence to give aspirin and HMG CoA
reductase inhibitors. Symptomatic Treatment
Glyceryl trinitrate used sublingually, either as a tablet or spray,
gives prompt relieve, and can be used prior to activities, which the patient
knows will provoke angina. Prophylactic Treatment
This consists of b-blockers,
Calcium antagonists, long acting nitrates and possibly potassium channel
activators. There is no commonly accepted algorithm; treatment needs to be
tailored to the patient. Combination therapy may be necessary however there is
little evidence to suggest that addition of a third drug is beneficial. Patients
not adequately controlled medically should be considered for revascularization. b-Blockers
Negative inotropic and negative chronotropic effect, thereby reducing
myocardial oxygen demand. They are the drug of choice in patients with previous
myocardial infarction, due to their proven benefit in secondary prevention.
Atenolol 50-100mg daily, most commonly prescribed. Metoprolol 25-30mg twice
daily is often used if there is impaired renal function. Contraindications: asthma, Left ventricular failure bradycardia. Long-acting Nitrates (e.g. Isorbide
mononitrate)
Particularly useful in patients that gain relief from nitrate sprays.
They reduce venous return, and hence intradiastolic pressures, reduce impedance
to emptying of the left ventricle and relax the tone of the coronary arteries.
Once daily preparations are available which have a smooth pharmokinetic profile
and avoid the problem of tolerance. For example isosorbide mononitrate slow
release 60mg/24hr PO Calcium Channel blockers block
calcium flux into the cell and the utilisation of calcium within the cell. They
relax coronary arteries, cause peripheral vasodilatation, and reduce force of
left ventricular contraction thereby reducing the oxygen demand of the
myocardium. Non-dihydropyridine calcium antagonists (e.g. diltiazem and
verapamil) also reduce heart rate. They are particularly useful antianginal
agents but should be used in caution B-blockers. Case control studies have shown
that high dose nifedipine (short acting dihydropyridine) is associated with
adverse outcome. Slow release formulations and the 3rd generation
agents (e.g. amlodipine) can be used once daily and have a smooth profile action
with no significant effect on heart rate and no significant negative inotropic
effect. Nicorandil 10-30mg/12h PO Is a
relatively new drug that combines a nitrate like activity with potassium channel
blockade. Whilst not used as a first line drug, it may be useful when there are
contraindications to the above agents. Hormone Replacement therapy may be cardioprotective Unstable Angina
Is a medical emergency, if untreated will progress to a MI in >10% of
cases. It requires : Antianginal therapy (diltiazem,
b-blocker, isosorbide dinitrate) Bedrest,
Aspirin Ê75mg/24hr Heparin 5000m
IV bolus then IV to maintain activated partial thromboplastin time 1.5-2.5 of
control. Should be given for at least 3 days and probably confers additional
benefit to that given by aspirin alone. Low molecular weight heparin
is an alternative e.g. enoxaprin 1mg/kg/12 subcutaneously. Recent trials have shown that
infusion of glycoprotein 2b/3a receptor inhibitors e.g. abciximab may have an
additional advantage other heparin and aspirin. These receptors are activated in
the final common pathway of platelet aggregation. AnginaStable
Treatment
Unstable
Treatment
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