Clinical Pharmacology and Therapeutics

MANAGEMENT OF STABLE ANGINA 197
Assess risk factors
Investigations: full blood count (exclude polycythaemia, either primary or secondary
to smoking, thrombocythaemia), plasma glucose and lipid profile
Aspirin 75 mg daily
Statin therapy
Modification of risk factors
Trial of anti-anginal medication
No significant improvement in symptoms
Adequate control of symptoms
Adequate control of risk factors
REFER TO CARDIOLOGIST
OR CHEST PAIN CLINIC
ANNUAL REVIEW
(Assessment of pain, risk factors)
Worsening of symptoms
or risk factors
Figure 29.1: General management of stable
angina.
order to prevent pain. Alternatively, long-acting nitrates (e.g.
isosorbide mononitrate) may be taken regularly to reduce the
frequency of attacks. Beta-blockers (usually of the ‘cardioselective’
type, e.g. atenolol, metoprolol or bisoprolol) or
calcium-channel blockers (most commonly diltiazem, less
commonly verapamil or one of the dihydropyridine drugs,
such as nifedipine or amlodipine) are also useful for chronic
prophylaxis (see below). Nicorandil combines nitrate-like
with K -channel-activating properties and relaxes veins and
arteries. It is used in acute and long-term prophylaxis of
angina, usually as an add-on to nitrates, beta-blockers and/or
calcium-channel blockers where these have been incompletely
effective, poorly tolerated or contraindicated. Statins (e.g. simvastatin
or atorvastatin) should be prescribed routinely for
cholesterol lowering unless there is a contraindication, regardless
of serum cholesterol (unless it is already very low: total
cholesterol 4 mmol/L and/or LDL cholesterol 2 mmol/L), as
numerous large studies have shown prognostic benefit in terms
of prevention of cardiac events and reduction in mortality.
CONSIDERATION OF SURGERY/ANGIOPLASTY
Cardiac catheterization identifies patients who would benefit
from coronary artery bypass graft (CABG) surgery or percutaneous
coronary intervention (PCI, which most commonly
involves balloon angioplasty of the affected coronary arteries
with concomitant stent insertion). Coronary artery disease is
progressive and there are two roles for such interventions:
1. symptom relief;
2. to improve outcome.
CABG and PCI are both excellent treatments for relieving the
symptoms of angina, although they are not a permanent cure
and symptoms may recur if there is restenosis, if the graft
becomes occluded, or if the underlying atheromatous disease
progresses. Restenosis following PCI is relatively common,
occurring in 20–30% of patients in the first four to six months
following the procedure, and various strategies are currently
under investigation for reducing the occurrence of restenosis;
one very promising strategy involves the use of ‘drug-eluting’
stents (stents which are coated with a thin polymer containing a
cytotoxic drug, usually sirolimus or paclitaxel, which suppresses
the hypertrophic vascular response to injury). PCI as
currently performed does not improve the final outcome in
terms of survival or myocardial infarction, whereas CABG can
benefit some patients. Those with significant disease in the left
main coronary artery survive longer if they are operated on and
so do patients with severe triple-vessel disease. Patients with
strongly positive stress cardiograms have a relatively high incidence
of such lesions, but unfortunately there is no foolproof
method of making such anatomical diagnoses non-invasively,
so the issue of which patients to subject to the low risks of invasive
study remains one of clinical judgement and of cost.
Surgical treatment consists of coronary artery grafting with
saphenous vein or, preferably, internal mammary artery (and
sometimes other artery segments, e.g. radial artery) to bypass
diseased segment(s) of coronary artery. Arterial bypass grafts
have a much longer patency life than vein grafts, the latter
usually becoming occluded after 10–15 years (and often after
much shorter periods). PCI has yet to be shown to prolong life
in the setting of stable angina, but can be valuable as a less
demanding alternative to surgery in patients with accessible