Angina Pictoris

This is due to myocardial ischaemia and presents as a central chest tightness or heaviness, which is brought on by exertion and relieved by rest.

It may radiate to one or both arms, the neck, jaw or teeth.

Other precipitants:

Emotion, cold weather, and heavy meals.

Associated symptoms:

Dyspnoea, nausea, sweatiness, faintness

Causes

Mostly atheroma.

Rarely: anaemia, AS; tachyarrhythmias; HCM; arteritis/small vessel disease (microvascular angina/cardiac syndrome X).

Types of angina

v _Stable angina:

induced by effort, relieved by rest.

v _Unstable (crescendo) angina:

Angina of increasing frequency or severity; occurs on minimal exertion or at rest; associated with ↑↑ risk of mi.

v _Decubitus angina:

precipitated by lying flat.

v _Variant (Prinzmetal's) angina:

caused by coronary artery spasm (rare; may co-exist with fixed stenoses).

Test

v _ECG:

usually normal, but may show ST depression; flat or inverted T waves; signs of past MI.

v _Other investigations:

It will be explained later.

Exclude precipitating factors:

anaemia, diabetes, hyperlipidaemia, thyrotoxicosis, temporal arteritis

Management

v _Modify risk factors:

stop smoking, encourage exercise, weight loss.

Control hypertension, diabetes, etc., section.

Cardiovascular medicine_----cardiovascular health

If total cholesterol & gt; 4mmol/L give a statin—see section.

Clinical chemistry----hyperlipidemia

v _Aspirin:

(75–150mg/24h) reduces mortality by 34%.

v _B-blockers:

eg atenolol 50–100mg/24h PO,

reduce symptoms unless contraindicated

(asthma, COPD, LVF, bradycardia, coronary artery spasm).

v _Nitrates:

for symptoms,

give GTN spray or sublingual tabs, up to every ½h.

Prophylaxis:

give regular oral nitrate,

eg isosorbide mononitrate 20–40mg PO bd

(have an 8h nitrate-free period to prevent tolerance) or slow-release nitrate (eg Imdur® 60mg/24h).

Alternatives:

adhesive nitrate skin patches or buccal pills.

SE:

headaches, BP↓.

v _Long-acting calcium antagonists:

amlodipine 10mg/24h;

diltiazem-MR 90–180mg/12h PO.

They are particularly useful if there is a contraindication to β-blockers.

v _K+ channel activator:

eg nicorandil 10–30mg/12h PO, if still not controlled.

v _Others:

ivabradine inhibits the pacemaker (‘funny’) current in the SA node and thus reduces heart rate.

Useful in those who cannot take a β-blocker, having similar efficacy.

Trimetazidine inhibits fatty acid oxidation, leading the myocardium to use glucose, which is more efficient.

Ranolazine inhibits the late Na+ current.

Unstable angina requires admission and urgent treatment: emergencies, see section.

Emergencies----acute management of ACS without ST-segment elevation.

Indications for referral

Diagnostic uncertainty; new angina of sudden onset; recurrent angina if past MI or CABG (see section); angina uncontrolled by drugs; unstable angina.

Some units routinely do exercise tolerance tests on those <70yrs old, but age alone is a poor way to stratify patients.

v _Percutaneous transluminal coronary angioplasty (PTCA):

involves balloon dilatation of the stenotic vessel(s).

Indications:

poor response or intolerance to medical therapy;

refractory angina in patients not suitable for CABG;

previous CABG;

post-thrombolysis in patients with severe stenoses, symptoms, or positive stress tests.

Comparisons of PTCA vs drugs alone show that PTCA may control symptoms better but with more frequent early cardiac events

(eg MI and need for CABG)  and little effect on mortality.

However, early intervention may benefit high risk patients presenting with non-ST-segment elevation MI (see section).

Stenting reduces restenosis rates and the need for bailout CABG compared with angioplasty.

Complications:

Restenosis (20–30% within 6 months);

emergency CABG (<3%); MI (<2%); death (<0.5%).

NICE recommends

that <70% of angioplasties be accompanied by stenting.

Antiplatelet agents,

eg clopidogrel, reduce the risk of stent thrombosis, and IV glycoproteins IIb/IIIa-inhibitors

(eg eptifibatide) reduce procedure-related ischaemic events.

Drug-coated stents reduce restenosis rates, but at the risk of increased late in-stent thrombosis.

Long-term treatment with aspirin and clopidogrel may reduce this risk .

Investigation patients with ?

v _Stable angina:

If the patient has an acute coronary syndrome,

eg unstable angina,

emergency admission is indicated.

In those patients with stable chest pain which might be cardiac who do not require emergency admission, a number of options exist.

NICE suggests stratifying based on whether there is known CAD, and the likelihood of CAD.

v _Known CAD:

and pain typical, no further investigation.

If atypical pain,

either exercise testing or functional imaging

(myocardial perfusion scintigraphy, stress echo, or MRI).

v _Unknown CAD:

Stratify of likelihood of CAD

_ >90% treat as known CAD

_ 61–90% angiography, or functional imaging if inappropriate

_ 30–60% functional imaging

_ 10–29% coronary artery calcification score with CT

_ <10% reconsider diagnosis.

Calculating the likelihood of CAD (percentages)

Values are percent of people at each mid-decade with significant coronary artery disease (CAD).

Hi = High risk = diabetes, smoking, and hyperlipidaemia (total cholesterol >6.47mmol/L).

Lo = Low risk = none of these three.

The shaded area represents people with symptoms of non-anginal chest pain, who would not be investigated for stable angina routinely.

For men older than 70 with atypical or typical symptoms, assume an estimate >90%.

For women older than 70, assume estimate of 61–90% EXCEPT women at high risk AND with typical symptoms, where a risk of >90% should be assumed.

Note:

these results are likely to overestimate CAD in primary care populations.

If there are resting ECG ST-T changes or Q waves,

the likelihood of CAD is higher in each cell of the table.

NICE (2010) CG95 Chest pain of recent onset: assessment and diagnosis of recent onset chest pain and discomfort of suspected cardiac origin.

London: NICE. Available from www.nice.org.uk/guidance/CG95.

Reproduced with permission.

Prinzmetal angina

This is due to coronary artery spasm, which can occur even in normal coronary arteries.

Pain usually occurs during rest (rather than during activity).

ECG during pain shows ST segment elevation, which resolves as the pain subsides.

Patients usually do not have the standard risk factors

for atherosclerosis.

Treatment:

Calcium channel blockers ± long-acting nitrates.

Aspirin can aggravate the ischaemic attacks in these patients.

β-blockers (esp non-selective) should also be avoided as they can increase vasospasm.

Prognosis is usually very good.

                                                                                                      

SOURCE ⏬⏬⏬
OXFORD HANDBOOK CLINICAL MEDICINE 9EDATION

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