Stable Angina

Quick Reference

Critical Alerts

• Distinguish stable from unstable angina: Unstable angina (rest pain, crescendo pattern, new-onset severe) is an ACS emergency requiring immediate admission
• CTCA is first-line investigation for suspected stable angina per NICE guidelines (not exercise stress test)
• All patients require secondary prevention: Aspirin, high-intensity statin, ACE inhibitor consideration regardless of symptom control
• GTN non-response after 3 doses (15 minutes) = call 999: Potential ACS, patient should not delay seeking emergency care
• COURAGE and ISCHEMIA trials: Revascularization in stable CAD does not reduce mortality vs optimal medical therapy; reserve for refractory symptoms or high-risk anatomy
• Beta-blockers are first-line anti-anginal therapy: Reduce heart rate and myocardial oxygen demand
• SYNTAX score guides PCI vs CABG decision: High SYNTAX score (> 32) favors CABG in multivessel disease
• FFR/iFR guides revascularization: Functional significance of stenosis matters more than angiographic appearance

Classic Presentation

Emergency Treatments

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Definition

Overview

Stable angina, now classified as Chronic Coronary Syndrome (CCS) in contemporary guidelines, is chest pain or discomfort caused by myocardial ischemia resulting from fixed obstructive coronary artery disease (typically > 70% stenosis of an epicardial coronary artery, or > 50% left main stem). [1,2] The condition is characterized by predictable, reproducible symptoms occurring with physical exertion, emotional stress, cold exposure, or after heavy meals, and is relieved by rest or sublingual nitrates within 5-10 minutes. [3]

Stable angina represents the most common initial presentation of coronary artery disease (CAD), affecting 2-4% of the adult population in developed countries. [4] It serves as a critical marker of underlying atherosclerotic cardiovascular disease, carrying a 2-3% annual risk of myocardial infarction or cardiovascular death without appropriate treatment. [5] Early diagnosis and optimal management can reduce this risk by 50% through secondary prevention and, where indicated, revascularization. [6]

The pathophysiology involves a supply-demand mismatch: during exertion, myocardial oxygen demand increases (due to increased heart rate, contractility, and wall tension), but coronary blood flow cannot increase adequately past the fixed stenosis, resulting in relative ischemia, anaerobic metabolism, lactate accumulation, and pain. [7]

Classification

Canadian Cardiovascular Society (CCS) Functional Classification [8]:

Clinical Significance of CCS Classification:

• CCS I-II: Generally managed medically with good quality of life
• CCS III-IV: Consider invasive investigation and revascularization if anatomy suitable
• CCS IV with rest angina: Overlaps with unstable angina/ACS spectrum - requires careful evaluation

By Syndrome Type (ESC 2019 Chronic Coronary Syndrome Classification) [1]:

1. Patients with suspected CAD and stable anginal symptoms and/or dyspnea
2. Patients with new-onset heart failure or LV dysfunction and suspected CAD
3. Asymptomatic and symptomatic patients with stabilized symptoms less than 1 year after ACS or revascularization
4. Asymptomatic and symptomatic patients > 1 year after initial diagnosis or revascularization
5. Patients with angina and suspected vasospastic or microvascular disease
6. Asymptomatic subjects with CAD detected at screening

Microvascular Angina (Cardiac Syndrome X) [74]

Definition: Angina pectoris with normal or near-normal coronary arteries on angiography, due to coronary microvascular dysfunction.

Characteristics:

• More common in women (female:male ratio 3:1)
• Typical exertional angina but normal epicardial coronaries (less than 50% stenosis)
• Positive stress testing (ischemic ECG changes, perfusion defects)
• Impaired coronary flow reserve (CFR less than 2.0 on PET or CMR)
• Prognosis: Generally favorable for survival but significant quality of life impact [75]

Diagnosis:

• Requires exclusion of obstructive CAD (CTCA or ICA)
• Demonstration of ischemia on functional testing
• CFR assessment via PET, CMR stress perfusion, or invasive coronary flow measurements
• Endothelial dysfunction testing (acetylcholine provocation - specialist centers)

Treatment [76]:

• Risk factor modification (as per obstructive CAD)
• Anti-anginal therapy: CCBs (amlodipine), beta-blockers, ranolazine effective
• ACE inhibitors (improve endothelial function)
• Consider statins (pleiotropic endothelial benefits)
• Avoid revascularization (ineffective; no obstructive lesions)
• Cardiac rehabilitation and psychological support

Epidemiology

Prevalence and Incidence:

• Prevalence (UK): 2-4% of adult population; 10-15% in > 65 years age group [4,9]
• Incidence (UK): 20,000-40,000 new cases per year [10]
• Global burden: Ischemic heart disease remains the leading cause of death worldwide [11]
• Healthcare impact: Significant contributor to hospital admissions, medication costs, and disability

Demographics:

• Age: Peak onset 55-75 years; risk increases exponentially with age
• Sex: Male predominance in younger ages (3:1 in less than 65 years), equalizes post-menopause [12]
  • Women present later (mean age 70 vs 66 years in men)
  • Women more likely to have atypical presentations
  • Microvascular angina more common in women
• Ethnicity: South Asian populations have 1.5-2 fold higher risk of CAD [13]
  • Higher rates of diabetes, insulin resistance, and adverse lipid profiles
  • Earlier age of onset

Risk Factors and Relative Risks [14,15]:

INTERHEART Study: Nine modifiable risk factors account for > 90% of population-attributable risk for MI globally [16]:

• Smoking, dyslipidemia, hypertension, diabetes, abdominal obesity, psychosocial factors, insufficient fruits/vegetables, regular alcohol, physical inactivity

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Pathophysiology

Atherosclerosis and Plaque Development

Stages of Atherogenesis [17,18]:

1. Endothelial Dysfunction and Injury

   • Causes: Shear stress, hypertension, smoking, hyperglycemia, hyperlipidemia
   • Results in increased permeability to LDL and monocytes
   • Reduced nitric oxide bioavailability

2. LDL Accumulation and Oxidation

   • LDL particles enter intima and undergo oxidation
   • Oxidized LDL is pro-inflammatory and cytotoxic
   • Triggers inflammatory cascade

3. Foam Cell Formation (Fatty Streak)

   • Monocytes differentiate into macrophages in intima
   • Macrophages engulf oxidized LDL via scavenger receptors
   • Lipid-laden macrophages become "foam cells"
   • Earliest visible lesion in atherosclerosis

4. Fibrous Plaque Formation

   • Smooth muscle cell migration from media to intima
   • Smooth muscle cells produce extracellular matrix (collagen, elastin)
   • Formation of fibrous cap overlying lipid core
   • Progressive luminal narrowing

5. Plaque Maturation

   • Stable plaque: Thick fibrous cap, small lipid core, minimal inflammation
   • Vulnerable plaque: Thin fibrous cap (less than 65 μm), large lipid-rich necrotic core, high inflammatory cell content
   • Stable plaques cause stable angina; vulnerable plaques cause ACS

Mechanism of Angina (Supply-Demand Mismatch) [7,19]

Determinants of Myocardial Oxygen DEMAND:

Determinants of Myocardial Oxygen SUPPLY:

Ischemic Cascade [20]:

1. Reduced coronary blood flow → Subendocardial ischemia (most vulnerable)
2. Metabolic changes → Lactate accumulation, ATP depletion
3. Diastolic dysfunction → Impaired relaxation
4. Systolic dysfunction → Wall motion abnormality
5. ECG changes → ST depression, T-wave inversion
6. Angina → Pain perception (last to occur)

Clinical Correlation: Patients may have silent ischemia (especially diabetics) with wall motion abnormalities and ECG changes but no pain.

Coronary Anatomy [21]

Left Coronary System:

• Left Main Stem (LMS): 1-2 cm length; supplies 75% of LV in left-dominant, 60% in right-dominant circulation
  • Stenosis > 50% is significant (critical)
  • "Left main equivalent" = proximal LAD + proximal Circumflex disease
• Left Anterior Descending (LAD): Supplies anterior wall, anterior septum, apex
  • Most commonly diseased coronary artery
  • Proximal LAD disease is high-risk (large territory at jeopardy)
  • Gives off septal perforators and diagonal branches
• Left Circumflex (LCx): Supplies lateral wall, posterior wall in left-dominant systems
  • Gives off obtuse marginal branches

Right Coronary System:

• Right Coronary Artery (RCA): Supplies RV, inferior wall, posterior wall in right-dominant systems
  • Supplies SA node in 60% and AV node in 90% of patients
  • Gives off posterior descending artery (PDA) in right-dominant circulation (85%)

Coronary Dominance:

• Right dominant (85%): RCA gives rise to PDA
• Left dominant (8%): LCx gives rise to PDA
• Co-dominant (7%): Both contribute

Collateral Circulation

• Develops in response to chronic ischemia
• Pre-existing anastomoses enlarge (arteriogenesis)
• Can provide significant blood flow to ischemic territory
• Explains why some patients with severe stenosis have limited symptoms
• Collateral-dependent myocardium may be at risk during revascularization

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Clinical Presentation

Symptoms

Typical Angina (Definite Angina) - Must have ALL THREE features [3,22]:

1. Constricting discomfort in chest, neck, jaw, shoulder, or arm
2. Precipitated by physical exertion
3. Relieved by rest or GTN within 5 minutes

Atypical Angina (Probable Angina): Two of the above three features

Non-Anginal Chest Pain: One or none of the above features

Characteristics of Angina:

Angina Equivalents (Common in elderly, diabetics, women) [23]:

• Exertional dyspnea (most common equivalent)
• Fatigue
• Nausea, indigestion (especially with inferior ischemia)
• Lightheadedness, presyncope
• Diaphoresis

Atypical Presentations More Common In:

• Women (50% present atypically)
• Elderly (> 75 years)
• Diabetics (autonomic neuropathy)
• Post-transplant patients
• Chronic kidney disease

"Do Not Miss"

• Unstable Features (ACS Spectrum) [24]

RED FLAGS - Urgent admission required:

Distinguishing Stable from Unstable Angina:

Variant (Prinzmetal) Angina [25]

Definition: Angina caused by coronary artery vasospasm, occurring at rest (often nocturnal), with transient ST elevation during episodes.

Characteristics:

• Occurs at rest, often between midnight and early morning
• ST elevation during pain (resolves with pain resolution)
• May occur in normal coronaries or superimposed on fixed stenosis
• Associated with smoking, cocaine, hyperventilation
• Episodes may be cyclical

Key Points:

• Avoid beta-blockers (may worsen vasospasm via unopposed alpha-vasoconstriction)
• Treat with calcium channel blockers (first-line) and nitrates
• Risk of arrhythmias during spasm (VT/VF)

History Taking

Essential Questions:

1. Pain Characteristics:

   • Where exactly is the pain/discomfort? Point to it.
   • What does it feel like? (Quality: pressure, tightness, heaviness)
   • How severe is it on a scale of 0-10?
   • How long does each episode last?
   • Does it spread anywhere? (Radiation)

2. Triggers and Relief:

   • What brings it on? (Exertion, cold, meals, stress)
   • How much activity triggers it? (Walking distance, stairs - for CCS grading)
   • What makes it go away? (Rest, GTN - and how quickly?)
   • Does it come on at rest? (RED FLAG)

3. Pattern and Progression:

   • How long have you had these symptoms?
   • Is the pattern stable or getting worse? (RED FLAG if worsening)
   • How often do you get episodes?

4. Associated Symptoms:

   • Breathlessness, nausea, sweating, palpitations, lightheadedness?

5. Risk Factor Assessment:

   • Smoking history (pack-years, current status)
   • Diabetes, hypertension, cholesterol history
   • Family history of premature CAD (less than 55 male, less than 65 female first-degree relative)
   • Previous vascular disease (stroke, TIA, PVD)

6. GTN Use:

   • Do you use GTN spray/tablets?
   • How often? How many doses needed?
   • Does it work within 5 minutes?
   • Any side effects? (Headache common)

7. Functional Status:

   • How is this affecting your daily life?
   • What activities can you no longer do?
   • Work impact?

Physical Examination

During Angina Episode (rarely witnessed):

• Diaphoresis, pallor
• Tachycardia, hypertension (sympathetic activation)
• S4 gallop (LV stiffness)
• Transient mitral regurgitation murmur (papillary muscle ischemia)

Between Episodes:

Key Point: Examination is often completely normal in stable angina between episodes.

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Differential Diagnosis

Cardiac Causes of Chest Pain

Non-Cardiac Causes of Chest Pain

Esophageal-Cardiac Differentiation Challenge

Both conditions can cause:

• Retrosternal discomfort
• Response to nitrates (esophageal spasm may respond)
• Radiation

Key Differentiators for Cardiac Origin:

• Exertional relationship (strongly suggests cardiac)
• Associated diaphoresis
• Response to rest
• Cardiovascular risk factors
• ECG changes during pain

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Diagnostic Approach

Clinical Probability Assessment

Pre-Test Probability (PTP) of obstructive CAD is based on age, sex, and symptom type. [3,26]

Updated ESC 2019 Pre-Test Probabilities (lower than historical Framingham-derived estimates):

Clinical Likelihood Modifiers (increase probability):

• Known CAD
• Diabetes
• Dyslipidemia
• Hypertension
• Smoking
• Family history
• ST-T changes on resting ECG
• Positive exercise test previously
• Coronary calcification on prior imaging

Probability Categories and Actions [1]:

• Very low PTP (less than 5%): Consider other diagnoses; non-invasive testing rarely indicated
• Low PTP (5-15%): Consider calcium scoring or CTCA
• Intermediate PTP (15-85%): Non-invasive testing indicated (CTCA preferred)
• High PTP (> 85%): Invasive coronary angiography may be appropriate

Investigations

Bedside Tests

12-Lead ECG [27]:

During Angina Episode:

• ST depression ≥1 mm (horizontal or downsloping) = significant ischemia
• ST elevation = severe transmural ischemia or vasospasm

Laboratory Investigations

Coronary Artery Calcium Score (CACS) [28]

When to Use:

• Low to intermediate PTP (5-15%)
• Uncertainty about need for further testing
• Asymptomatic individuals for risk stratification

Interpretation:

Limitations: Does not detect non-calcified ("soft") plaque; may be falsely low in younger patients or acute presentations.

CT Coronary Angiography (CTCA) [29,30]

NICE Recommendation (NG95): CTCA is first-line anatomical test for patients with chest pain of recent onset where CAD cannot be excluded by clinical assessment alone.

Advantages:

• Non-invasive
• Excellent negative predictive value (rules out CAD effectively)
• Visualizes plaque morphology and coronary anatomy
• Fast acquisition (~5 seconds)
• Can identify non-coronary causes of chest pain

Limitations:

• Requires heart rate control (beta-blocker often given if HR > 60)
• Contrast exposure
• Radiation exposure (3-5 mSv with modern scanners)
• Reduced accuracy with extensive calcification, arrhythmias, high BMI
• Cannot assess functional significance of intermediate stenoses (50-70%)

Post-CTCA Decision:

• No/mild CAD (less than 50%): Reassure, secondary prevention
• Moderate stenosis (50-70%): Functional testing (stress imaging) or FFR-CT
• Severe stenosis (> 70%): Invasive angiography for revascularization planning

FFR-CT (CT-Derived Fractional Flow Reserve) [77,78]:

• Non-invasive functional assessment derived from CTCA datasets using computational fluid dynamics
• FFR-CT ≤0.80: Hemodynamically significant stenosis
• FFR-CT > 0.80: Non-significant stenosis; optimal medical therapy
• Advantages: No additional imaging, no adenosine, no radiation beyond CTCA
• Evidence: PLATFORM, ADVANCE trials show reduced unnecessary ICA, cost-effective
• Increasingly integrated into CTCA reporting workflows

Functional (Stress) Testing

Principles: Detect myocardial ischemia by increasing myocardial oxygen demand (exercise or pharmacological stress) and detecting ischemia via ECG, imaging (perfusion or wall motion), or symptoms. [31]

Exercise Tolerance Test (ETT) / Exercise ECG [32]:

Indications:

• Assessment of exercise capacity
• Symptom-exercise correlation
• Post-revascularization assessment

Contraindications:

• Recent MI (less than 48 hours)
• Unstable angina
• Severe symptomatic aortic stenosis
• Acute myocarditis/pericarditis
• Acute PE or aortic dissection
• Uncontrolled arrhythmias
• Inability to exercise

Duke Treadmill Score (DTS) [33]:

• Formula: Exercise time (min) - (5 × ST deviation in mm) - (4 × angina index)
  • "Angina index: 0 = no angina; 1 = non-limiting angina; 2 = exercise-limiting angina"
• Low risk (≥5): 0.25% annual mortality
• Moderate risk (-10 to +4): 1.25% annual mortality
• High risk (≤-11): 5.25% annual mortality

Stress Echocardiography [34]:

Advantages: No radiation, assesses LV function, valvular disease

Myocardial Perfusion Imaging (MPI / SPECT) [35]:

Advantages: High sensitivity, semi-quantitative ischemia assessment, viability assessment

Cardiac MRI (CMR) Stress Perfusion [36]:

Advantages: No radiation, excellent spatial resolution, assesses viability (late gadolinium enhancement)

PET Perfusion Imaging [37]:

• Highest diagnostic accuracy among functional tests
• Allows absolute myocardial blood flow quantification
• Limited availability, expensive
• Used for microvascular disease assessment

Invasive Coronary Angiography (ICA) [38]

Gold Standard for coronary anatomy assessment and definitive diagnosis.

Indications:

• High clinical probability of CAD with refractory symptoms
• High-risk features on non-invasive testing
• Inconclusive non-invasive testing
• Consideration of revascularization
• Severe stenosis on CTCA
• Post-STEMI/NSTEMI

Key Outputs:

• Number and location of diseased vessels
• Severity of stenoses (% diameter stenosis)
• LV function (LV gram)
• Planning for revascularization (PCI vs CABG)

Limitations:

• Invasive procedure (vascular access, contrast, radiation)
• Angiographic severity does not always correlate with functional significance
• Complications: Bleeding, vascular injury, stroke, MI, death (overall major complication rate less than 1%)

Fractional Flow Reserve (FFR) and Instantaneous Wave-Free Ratio (iFR) [39,40]

Purpose: Assess functional significance of intermediate coronary stenoses (40-70% on angiography).

FFR:

• Measured during maximum hyperemia (adenosine infusion)
• Ratio of distal coronary pressure to aortic pressure
• FFR ≤0.80: Functionally significant → benefits from revascularization
• FFR > 0.80: Not significant → optimal medical therapy

iFR:

• Measured during the wave-free period of diastole (no adenosine needed)
• iFR ≤0.89: Functionally significant
• iFR > 0.89: Not significant

Evidence (FAME, FAME 2, iFR-SWEDEHEART, DEFINE-FLAIR):

• FFR/iFR-guided PCI improves outcomes compared to angiography-guided PCI
• FAME 2: FFR-guided PCI reduced urgent revascularization compared to medical therapy alone

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Treatment

Principles of Management

Stable angina management is multimodal, targeting: [1,41]

1. Symptom Relief: Anti-anginal therapy to reduce angina frequency and improve quality of life
2. Secondary Prevention: Disease-modifying therapy to reduce cardiovascular events (MI, stroke, death)
3. Lifestyle Modification: Risk factor control through behavioral changes
4. Revascularization: When indicated for refractory symptoms or high-risk anatomy

Treatment Goals:

• Abolish or reduce angina to CCS I-II
• Reduce frequency of GTN use
• Improve exercise capacity and quality of life
• Reduce cardiovascular morbidity and mortality
• Prevent progression to ACS

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Medical Management

Anti-Anginal Therapy (Symptom Relief) [42,43]

First-Line Agents (Choose ONE):

1. Beta-Blockers (First-Line Preferred) [44,45]:

Mechanism: Reduce heart rate (negative chronotropy), contractility (negative inotropy), and blood pressure → decreased myocardial oxygen demand.

Target: Resting HR 55-60 bpm.

Contraindications: Asthma (severe/uncontrolled), acute decompensated heart failure, severe bradycardia (less than 50 bpm), second/third-degree AV block, sick sinus syndrome (without pacemaker), severe hypotension.

Side Effects: Bradycardia, fatigue, cold extremities, erectile dysfunction, depression, bronchospasm, masking of hypoglycemia.

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2. Calcium Channel Blockers (Alternative First-Line) [46]:

Rate-Limiting CCBs (Non-Dihydropyridines) - use if beta-blocker contraindicated:

Contraindications: Heart failure with reduced EF (negative inotropy), second/third-degree AV block, severe bradycardia, hypotension. Do NOT combine with beta-blockers (risk of severe bradycardia/heart block).

Dihydropyridine CCBs - use in combination with beta-blockers:

Mechanism: Coronary and peripheral vasodilation (DHP); reduce heart rate and contractility (non-DHP).

Side Effects: Peripheral edema (ankle swelling, especially amlodipine), flushing, headache, constipation (verapamil), bradycardia (non-DHP).

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Add-On/Second-Line Anti-Anginals (if monotherapy insufficient):

3. Long-Acting Nitrates [47]:

Mechanism: Venodilation → reduced preload → reduced LV wall tension and O2 demand; some coronary vasodilation.

CRITICAL: Nitrate-free interval (10-14 hours) essential to prevent tolerance (typically overnight).

Side Effects: Headache (common initially, often improves), flushing, hypotension, dizziness, tolerance.

Contraindication: Concurrent use of PDE5 inhibitors (sildenafil, tadalafil, vardenafil) - severe hypotension risk; severe aortic stenosis.

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4. Nicorandil [48]:

Evidence: IONA trial showed reduced cardiovascular events in stable angina.

Side Effects: Headache, flushing, GI ulceration (rare but serious - oral, GI, anal ulcers), dizziness.

Contraindication: Concurrent PDE5 inhibitors.

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5. Ivabradine [49]:

Indications:

• Beta-blocker intolerant/contraindicated AND sinus rhythm AND HR > 70 bpm
• Add-on to beta-blocker if HR remains > 70 bpm

Contraindications: Atrial fibrillation (only works in sinus rhythm), severe bradycardia (less than 60 bpm pre-treatment), sick sinus syndrome, SA/AV block, acute MI, cardiogenic shock, concurrent strong CYP3A4 inhibitors.

Side Effects: Visual disturbances (phosphenes - transient brightness), bradycardia, AF, headache.

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6. Ranolazine [50]:

Indications: Refractory angina as add-on therapy when other agents inadequate or contraindicated.

Contraindications: Severe hepatic impairment, concurrent potent CYP3A4 inhibitors, QT prolongation.

Side Effects: Dizziness, nausea, constipation, QT prolongation.

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GTN (Glyceryl Trinitrate) - Acute Symptom Reliever [51]:

Instructions:

• Use at first sign of angina OR prophylactically before exertion
• Sit down before using (hypotension risk)
• One spray/tablet, wait 5 minutes; repeat up to 3 times
• If no relief after 3 doses (15 minutes) → CALL 999 (ambulance) - suspect ACS
• Common side effects: Headache, flushing, dizziness

Practical Points:

• Replace spray/tablets every 8 weeks (GTN degrades)
• Avoid within 24 hours of sildenafil/vardenafil; 48 hours of tadalafil

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Secondary Prevention (Disease-Modifying Therapy) [52,53]

ALL patients with stable angina/CAD require:

1. Antiplatelet Therapy:

Post-PCI: DAPT (Aspirin + P2Y12 inhibitor) for 6-12 months typically [54].

2. High-Intensity Statin Therapy [55]:

Evidence: 4S, LIPID, HPS, PROVE-IT TIMI 22 trials - statins reduce MI, stroke, cardiovascular death by 30-40% [56].

ESC 2019 Target: LDL less than 1.4 mmol/L AND ≥50% reduction from baseline for very high-risk patients (established CAD).

Monitoring: Check lipids at 8-12 weeks after starting/changing dose; LFTs at baseline, 8-12 weeks, then annually.

3. ACE Inhibitors [57]:

Indications (consider for all CAD patients; mandatory if):

• Diabetes mellitus
• Chronic kidney disease (albuminuria)
• LV systolic dysfunction (EF less than 40%)
• Hypertension
• Post-MI

Evidence: HOPE trial (ramipril) and EUROPA trial (perindopril) showed 20-25% relative risk reduction in cardiovascular events in CAD patients [58,59].

ARBs: Use if ACE inhibitor intolerant (cough, angioedema).

4. Blood Pressure Control:

• Target: less than 130/80 mmHg (if tolerated) for most patients with CAD [60]
• First-line: ACE inhibitor/ARB + CCB (amlodipine) ± thiazide

5. Glycemic Control (Diabetics):

• Target HbA1 c: less than 53 mmol/mol (7%) for most; individualize
• Consider SGLT2 inhibitors or GLP-1 agonists (cardiovascular benefit) [61]

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Lifestyle Modification [62]

Critical for all patients - address at every consultation:

Cardiac Rehabilitation:

• All stable angina patients should be offered cardiac rehabilitation
• Components: Supervised exercise, education, dietary advice, psychological support, smoking cessation
• Mortality benefit: 20-25% reduction [63]

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Revascularization [64,65]

Indications for Invasive Angiography and Revascularization:

1. Refractory symptoms (CCS III-IV) despite optimal medical therapy
2. High-risk anatomy identified on non-invasive testing
3. Large area of ischemia (> 10% of LV myocardium) on functional testing
4. LV systolic dysfunction attributable to ischemia
5. Prognostic benefit (specific anatomical subsets)

PCI (Percutaneous Coronary Intervention) [66]

Technique: Balloon angioplasty + drug-eluting stent (DES) deployment via catheter.

Indications:

• 1-2 vessel disease without proximal LAD involvement
• Low-intermediate SYNTAX score (≤22)
• Patient preference for less invasive approach
• High surgical risk

Outcomes:

• Procedural success: > 95%
• In-hospital mortality: less than 1%
• Target lesion revascularization (DES): 5-10% at 5 years

Post-PCI Antiplatelet Therapy [54]:

CABG (Coronary Artery Bypass Grafting) [67]

Technique: Surgical bypass using arterial (LIMA, RIMA, radial) or venous (SVG) conduits.

Indications for CABG over PCI:

• Left main stem disease (> 50% stenosis)
• Three-vessel disease, especially with:
  • Diabetes mellitus
  • Reduced LV function (EF less than 50%)
  • High SYNTAX score (> 32)
  • Complex lesions (bifurcation, calcification, chronic total occlusion)
• Two-vessel disease with proximal LAD involvement

SYNTAX Score [68]:

• Anatomical complexity scoring system based on angiographic features
• Low (0-22): PCI or CABG similar outcomes
• Intermediate (23-32): Case-by-case; Heart Team discussion
• High (> 32): CABG preferred

Evidence (SYNTAX, FREEDOM, EXCEL, NOBLE trials):

• 3-vessel/left main disease: CABG superior long-term outcomes (lower MACE, repeat revascularization)
• FREEDOM trial: CABG superior to PCI in diabetics with multivessel disease [69]

Conduit Patency:

• LIMA to LAD: 95% patency at 10 years
• SVG: 50-60% patency at 10 years

Perioperative Risks:

• Mortality: 1-3%
• Stroke: 1-2%
• MI: 2-5%
• Atrial fibrillation: 25-30%
• Wound infection: 2-5%

COURAGE and ISCHEMIA Trials - Key Evidence [70,71]

COURAGE Trial (2007):

• Question: PCI + OMT vs OMT alone in stable CAD?
• Result: No difference in death or MI at 4.6 years
• Conclusion: PCI provides symptom relief but does not reduce mortality/MI over OMT in stable CAD

ISCHEMIA Trial (2020):

• Question: Invasive strategy (angiography ± revascularization) vs conservative (OMT alone) in stable ischemic heart disease with moderate-severe ischemia?
• Result: No difference in CV death, MI, hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest at 3.2 years
• Conclusion: Initial conservative strategy reasonable; revascularization reserved for refractory symptoms or high-risk anatomy

Clinical Implications:

• Revascularization in stable CAD is primarily for symptom relief
• All patients require optimal medical therapy regardless of revascularization status
• Reserve revascularization for refractory symptoms or prognostic indications (left main, severe 3VD)

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Complications

Progression of Disease

Treatment-Related Complications

Medication Side Effects:

PCI Complications:

CABG Complications:

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Prognosis

Natural History and Outcomes [72,73]

Stable Angina (All-Comers):

• Annual mortality: 1-2%
• Annual MI rate: 2-3%
• 5-year survival: 85-90%

By Anatomical Severity:

Prognostic Factors (Poor Prognosis):

• Left main stem disease
• Proximal LAD disease
• Three-vessel disease
• LV systolic dysfunction (EF less than 40%)
• Large area of ischemia (> 10% LV)
• Diabetes mellitus
• Advanced age (> 75 years)
• CKD
• Prior MI
• Poor exercise tolerance (Duke score ≤-11)

Response to Treatment

Symptom Control:

• Optimal medical therapy: 70-80% achieve CCS I-II
• PCI: 85-90% symptom improvement at 1 year
• CABG: 90-95% symptom-free at 1-5 years

Secondary Prevention Impact:

• Statins: 30-40% reduction in cardiovascular events
• Aspirin: 22% reduction in vascular events
• ACE inhibitors: 20-25% reduction (HOPE, EUROPA)
• Smoking cessation: 50% risk reduction

Contemporary Outcomes (2020-2024 Data) [79,80]:

• Modern OMT (aspirin, high-intensity statin, ACEi, beta-blocker) reduces 5-year MACE by 45-50%
• Drug-eluting stent technology: Target lesion failure less than 5% at 5 years
• Contemporary CABG (LIMA + arterial grafts): 10-year survival 85-90% in low-risk patients
• All-cause mortality stable angina (OMT era): 0.8-1.2% per year in contemporary cohorts

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Patient Education

Condition Explanation

"You have angina, which is chest pain caused by narrowed arteries to your heart. The narrowing is due to a buildup of fatty deposits (atherosclerosis). When you exercise or exert yourself, your heart needs more oxygen, but the narrowed arteries can't deliver enough blood flow to meet that demand. This causes the chest pain or discomfort you experience."

"Angina is a warning sign that your heart arteries are narrowed, but the good news is that we can treat it effectively with medications that both relieve your symptoms and reduce your risk of having a heart attack in the future."

Medication Guidance

"We treat angina with two types of medication:

1. Symptom relief (like beta-blockers or calcium channel blockers to prevent pain, and GTN spray for immediate relief)
2. Heart protection (aspirin to thin your blood, statins to lower cholesterol, and sometimes blood pressure tablets) - these reduce your risk of heart attacks and strokes by 30-40%"

"It's very important to take your heart protection medications every day, even when you feel well. These are the medications that save lives."

GTN Spray Instructions

"Keep your GTN spray with you at all times. Use it at the first sign of chest pain:

1. Sit down before using it (it can make you feel lightheaded)
2. Spray once or twice under your tongue
3. Wait 5 minutes - the pain should improve
4. If not better, spray again (up to 3 times total, 5 minutes apart)
5. If pain persists after 3 doses (15 minutes), call 999 immediately - this could be a heart attack"

"You can also use GTN spray before activities you know cause angina (like climbing stairs or walking uphill)."

When to Seek Emergency Care

Call 999 immediately if:

• Chest pain lasting more than 15 minutes
• Chest pain not relieved by 3 doses of GTN
• Chest pain occurring at rest (not during activity)
• Pain more severe than usual
• Feeling very unwell - sweaty, nauseous, breathless
• Pain spreading to jaw, arm, or back

Lifestyle Advice

"There are important changes you can make that will significantly reduce your risk:

• Stop smoking - this is the single most important thing you can do
• Eat a Mediterranean diet - more fish, olive oil, vegetables, less processed food
• Stay active - aim for 30 minutes of moderate activity most days; we'll refer you to cardiac rehabilitation
• Maintain a healthy weight
• Limit alcohol - no more than 14 units per week"

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Quality Metrics

Performance Indicators

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Key Clinical Pearls

Diagnostic Pearls

1. Typical angina has 3 features: Retrosternal constricting discomfort + exertion-related + relieved by rest/GTN within 5 min
2. 50% of stable angina patients have normal resting ECG: Do not rely on ECG to diagnose or exclude angina
3. CTCA is first-line investigation (NICE NG95): Not exercise stress testing
4. Functional significance matters more than angiographic appearance: Use FFR/iFR for intermediate stenoses (40-70%)
5. Atypical presentations are common in women, diabetics, elderly: Maintain high clinical suspicion

Treatment Pearls

1. Beta-blockers are first-line anti-anginal: Target HR 55-60 bpm
2. Nitrate-free interval essential: Prevents tolerance (10-14 hours overnight)
3. Don't combine verapamil/diltiazem with beta-blockers: Risk of severe bradycardia/heart block
4. All patients need secondary prevention: Aspirin + statin + consider ACEi - even if asymptomatic on anti-anginals
5. COURAGE and ISCHEMIA trials: Revascularization doesn't reduce mortality in stable CAD vs OMT; reserve for symptoms or high-risk anatomy

Revascularization Pearls

1. SYNTAX score guides PCI vs CABG: High score (> 32) favors CABG
2. CABG superior in diabetics with multivessel disease: FREEDOM trial
3. LIMA to LAD is gold standard conduit: 95% patency at 10 years
4. Post-PCI DAPT typically 6-12 months: Balance ischemic and bleeding risk

Red Flag Pearls

1. Rest pain, crescendo pattern, new-onset severe = unstable angina (ACS): Emergency admission
2. No response to 3 GTN doses = call 999: Suspect MI
3. Angina with syncope suggests aortic stenosis: Listen for murmur; arrange echo
4. Sudden severe "tearing" chest pain = aortic dissection: CT aorta

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Viva Questions

Common Viva Questions

1. "Differentiate stable angina from unstable angina."

   • Stable: Predictable, exertional, consistent pattern, relieved by rest/GTN in 5-10 min
   • Unstable: Rest pain, crescendo, new-onset severe (less than 2 months), prolonged (> 20 min), incomplete relief = ACS spectrum requiring emergency admission

2. "What is the first-line investigation for suspected stable angina?"

   • CTCA per NICE NG95 guidelines
   • High sensitivity (95-99%) and excellent NPV (99%) for ruling out significant CAD

3. "Describe the medical management of stable angina."

   • Anti-anginal (symptom relief): BB (first-line) or CCB; add long-acting nitrate, nicorandil, ivabradine if needed; GTN PRN
   • Secondary prevention: Aspirin 75 mg, high-intensity statin (atorvastatin 80 mg), ACEi (ramipril 10 mg) if indicated

4. "What are the indications for CABG over PCI?"

   • Left main stem disease (> 50% stenosis)
   • Three-vessel disease, especially with diabetes, reduced EF, high SYNTAX score (> 32)
   • Two-vessel disease with proximal LAD involvement
   • Complex lesions not suitable for PCI

5. "What did the COURAGE and ISCHEMIA trials show?"

   • PCI + OMT does not reduce death or MI compared to OMT alone in stable CAD
   • Revascularization provides symptom relief but not prognostic benefit in stable disease
   • Initial conservative strategy is reasonable; reserve revascularization for refractory symptoms or high-risk anatomy

6. "What is the CCS classification of angina?"

   • CCS I: Angina only with strenuous exertion
   • CCS II: Angina with walking > 2 blocks or > 1 flight stairs
   • CCS III: Angina with walking 1-2 blocks or 1 flight stairs
   • CCS IV: Angina at rest or with any activity

7. "What is FFR and when is it used?"

   • Fractional Flow Reserve: Ratio of distal coronary pressure to aortic pressure during maximal hyperemia
   • Used to assess functional significance of intermediate stenoses (40-70%)
   • FFR ≤0.80 indicates hemodynamically significant stenosis warranting revascularization

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Future Directions

1. Coronary Computed Tomography Angiography-derived FFR (FFR-CT): Non-invasive functional assessment
2. Novel Anti-Anginal Agents: New targets for refractory angina
3. CGRP Antagonists: Exploring cardiovascular applications
4. Gene Therapy and Regenerative Medicine: Therapeutic angiogenesis for refractory angina
5. Precision Medicine: Genetic risk scoring and personalized therapy
6. AI-Assisted Diagnosis: Machine learning for CAD prediction and risk stratification
7. Bioresorbable Vascular Scaffolds: Future of coronary intervention (currently limited)

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