unstable angina

Question 1

what set of conditions is unstable angina a part of ?

Answer 1

acute coronary syndrome

Question 2

what is unstable angina?

Answer 2

characterised by chest discomfort typically occurring at rest or with minimal exertion.

Question 3

what causes unstable angina?

Answer 3

It’s due to transient myocardial ischaemia (imbalance between myocardial oxygen demand and supply), often resulting from atherosclerotic plaque rupture and subsequent thrombus formation in the coronary arteries.

Question 4

how is unstable angina different from stable?

Answer 4

This condition differs from stable angina as it can occur unpredictably and isn’t necessarily triggered by physical exertion or emotional stress.

Question 5

what are risk factors for unstable angina?

Answer 5

men >45, women >55
smoking
high cholesterol
hypertension
DM
obesity
sedentary lifestyle
cocaine use
FH

Question 6

what is the pathophysiology of unstable angina?

Answer 6

1. disruption of atherosclerotic plaque within coronary artery. exposes collagen + TF
2. platelets adhere to exposed sub-endothelial collagen and are activated
3. fibrinogen bridges cause platelet aggregation, activating coat factors and creates a clot
4. The clot obstructs the lumen of the coronary artery either partially (resulting in UA) or completely (resulting in myocardial infarction). This leads to a decrease in oxygen supply to the downstream myocardium.
5. The reduced blood flow cannot meet the metabolic demands of the myocardium under stress, leading to ischaemia.

Question 7

what are the different classifications of unstable angina based on symptoms?

Answer 7

• New-onset severe angina - developed within the last month
• Increasing or crescendo angina - progressive increase in severity, frequency or duration of anginal episodes over time. It often indicates worsening coronary artery disease and impending acute coronary syndrome.
• Rest or nocturnal angina - anginal pain at rest or during sleep usually suggests significant coronary artery obstruction.

Question 8

what are the braunwald classes of unstable angina?

Answer 8

Braunwald Class I: Unstable angina secondary to increased oxygen demand such as fever, tachycardia, thyrotoxicosis or anaemia.

Braunwald Class II: Unstable angina secondary to decreased oxygen supply such as hypoxia, anaemia or hypotension.

Braunwald Class III: Unstable angina at rest; subdivided into A (not previously treated), B (treated but recurrent) and C (post-infarction).

Question 9

what are the clinical features of angina?

Answer 9

anginal pain which occurs at rest, with minimal exertion or with an increasing frequency
pain may radiate to neck, jaw, epigastrium or L arm
dyspnoea
syncope
n+v
sweating

Question 10

what are the physical examination findings of unstable angina?

Answer 10

often normal between episodes
S4, hypotension, transient mitral regurgitation
may have features of congestive heart failure - elevated JVP, pulmonary rales, peripheral oedema
pallor + cool extremities in severe cases

Question 11

what investigations are done?

Answer 11

troponin - Troponin I or T levels should be measured at presentation and 3 hours after symptom onset.
ECG - may show changes but normal does not exclude unstable angina

echo, CXR

use GRACE score to determine if pt needs coronary angiography

Question 12

what are the differentials?

Answer 12

MI
GORD
MSK chest pain

Question 13

what is the management?

Answer 13

dual anti platelet
nitrates for immediate pain relief
BB +/- CCB
statins

PCI/CABG for severe
lifestyle modifications

Question 14

what are the complications?

Answer 14

acute MI
arrhythmias