Stable Angina Clinical Overview

Written By Danial Mirza

I. The "On-Call" Snapshot

  • Clinical Significance in Malaysia: This is the classic presentation of coronary artery disease in the outpatient clinic. Your job is to confirm it, optimise medical therapy, and most importantly, recognise when it becomes unstable.

  • High-Yield Definition: According to the Malaysian CPG for Stable Coronary Artery Disease (2nd Ed.), stable angina is a clinical syndrome characterized by discomfort in the chest, jaw, shoulder, back or arm, typically precipitated by exertion or emotional stress and relieved by rest or nitroglycerin.

  • Clinical One-Liner: Basically, it's predictable chest pain on effort because a narrowed coronary artery can't supply enough oxygen when the heart works harder.

II. Etiology & Risk Factors

  • Etiology: The overwhelming cause is coronary atherosclerosis—a fixed plaque narrowing the vessel lumen.

  • Risk Factors: You must actively screen for these in every patient. They are rampant in our population.

    • Non-Modifiable:

      • Age (Men > 45, Women > 55)

      • Male gender

      • Family history of premature coronary artery disease (CAD)

    • Modifiable:

      • Diabetes Mellitus (T2DM): Extremely common here. Poor control is a major driver.

      • Hypertension: Often undertreated.

      • Dyslipidemia: High LDL, low HDL.

      • Smoking: Ask about rokok daun and vape as well.

      • Obesity & Sedentary Lifestyle

III. Quick Pathophysiology

It’s a simple supply and demand problem. A fixed atherosclerotic plaque causes >70% stenosis in a coronary artery. At rest, blood flow is adequate. During exertion (e.g., climbing stairs, rushing to LRT), heart rate and contractility increase, raising myocardial oxygen demand. The fixed stenosis prevents a corresponding increase in blood flow (supply). This supply-demand mismatch causes transient myocardial ischemia, which the patient feels as angina. When they rest, demand drops, the mismatch corrects, and the pain resolves. No tissue death, no infarction.

IV. Clinical Assessment

  • Red Flags & Immediate Actions (Suspect Unstable Angina/ACS):

    • Rest Angina: Pain occurring without any trigger. → Action: Treat as ACS, get an immediate ECG, alert your senior, secure IV access.

    • Prolonged Pain (>20 mins): Not relieved by rest or GTN. → Action: Same as above. Do not send this patient home.

    • New Onset Angina (CCS Class III-IV): Severe symptoms with minimal exertion from the start. → Action: High risk. Discuss with senior for expedited assessment, possibly admission.

    • Dynamic ECG changes: ST depression or T-wave inversion during pain. → Action: This is unstable angina until proven otherwise. Admit.

  • History: The history is everything. A good history gives you the diagnosis 80% of the time.

    • Common (>50%):

      • Character: Squeezing, heaviness, pressure ("rasa berat," "rasa ketat"). Not a sharp, stabbing pain.

      • Location: Retrosternal.

      • Radiation: To the left arm, neck, or jaw.

      • Aggravating factors: Predictable level of physical exertion (e.g., "after walking up one flight of stairs"), emotional stress.

      • Relieving factors: Rest or sublingual GTN, usually within 5 minutes.

    • Pertinent Negatives:

      • No change with breathing (not pleuritic).

      • No change with posture or palpation (not musculoskeletal).

      • Not associated with meals (less likely GERD, but can co-exist).

  • Physical Examination: Often completely normal between episodes. You are looking for clues of risk factors and complications.

    • General: Signs of dyslipidemia (xanthelasma, arcus senilis), nicotine staining.

    • Vitals: Check for hypertension.

    • Cardiovascular: Listen for carotid bruits, assess peripheral pulses (evidence of generalized atherosclerosis). Check for signs of heart failure (raised JVP, S3 gallop, basal crepitations) which suggest significant underlying LV dysfunction.

  • Clinical Pearl: Always ask the patient "What can you not do anymore because of the chest pain?". This helps you objectively classify the severity and functional limitation.

V. Diagnostic Workflow

  • Differential Diagnosis:

    1. Acute Coronary Syndrome (ACS):

      • Points For: Similar pain character.

      • Points Against: Pain is prolonged, occurs at rest, or is of increasing severity.

      • How to Differentiate: Serial ECGs and cardiac troponins.

    2. Gastroesophageal Reflux Disease (GERD):

      • Points For: Burning retrosternal pain.

      • Points Against: Usually related to meals, lying down. Relieved by antacids. Not related to exertion.

      • How to Differentiate: Therapeutic trial of a proton pump inhibitor (PPI).

    3. Musculoskeletal Pain (e.g., costochondritis):

      • Points For: Chest wall pain.

      • Points Against: Pain is sharp, localized, and reproducible on palpation.

      • How to Differentiate: Tenderness on examination.

    4. Pulmonary Embolism:

      • Points For: Can present with central chest pain and SOB.

      • Points Against: Pain is typically pleuritic. Associated with tachycardia, hypoxia, and risk factors (immobility, surgery, malignancy).

      • How to Differentiate: CT Pulmonary Angiogram (CTPA) is the gold standard.

  • Investigations Plan:

    • Bedside / Initial:

      • Resting 12-lead ECG: May be normal. Look for evidence of prior MI (Q waves), LVH, or bundle branch blocks. An ECG during an episode of pain is invaluable and may show transient ST depression.

    • First-Line Labs & Imaging:

      • Bloods: FBC (check for anemia), renal profile (for ACEi/ARB and contrast), HbA1c, fasting lipid profile.

      • Chest X-ray: To check for cardiomegaly or pulmonary congestion.

    • Confirmatory / Risk Stratification:

      • Exercise Stress Test (EST): The most common initial non-invasive test in our setting. We look for clinical (chest pain) and electrical (ST depression ≥1mm) evidence of ischemia.

      • Stress Echocardiogram / Myocardial Perfusion Scan: Used if baseline ECG is abnormal (e.g., LBBB) or if EST is equivocal.

      • CT Coronary Angiography (CCTA): Excellent for ruling out CAD in low-intermediate risk patients. Has high negative predictive value.

      • Invasive Coronary Angiogram: The gold standard. Used for definitive diagnosis in high-risk patients or when revascularization is being considered.

VI. Staging & Severity Assessment

We use the Canadian Cardiovascular Society (CCS) Functional Classification. You must document this.

  • Class I: Angina only during strenuous or prolonged exertion.

  • Class II: Slight limitation of ordinary activity (e.g., angina on walking >2 blocks or climbing >1 flight of stairs rapidly).

  • Class III: Marked limitation. Angina on walking <2 blocks or climbing one flight of stairs at a normal pace.

  • Class IV: Inability to carry on any physical activity without discomfort. Angina may be present at rest.

Impact on management: Patients with CCS Class III-IV symptoms or those who are high-risk on non-invasive testing are candidates for angiography and revascularization.

VII. Management Plan

  • Immediate Symptomatic Relief:

    • Sublingual Glyceryl Trinitrate (GTN) 500mcg tablet.

    • Patient education is crucial: Take one tablet under the tongue when pain starts. Can repeat up to 3 times, 5 minutes apart. If pain persists after 3 tablets or 15 minutes, call 999 - treat it as a heart attack.

  • Definitive Treatment (The "ABCDE" Ward Round Plan):

    • A - Aspirin & Anti-anginals:

      • Aspirin: 75-150mg daily for secondary prevention. Clopidogrel 75mg daily if intolerant to aspirin.

      • Beta-blockers (First-line anti-anginal): e.g., Metoprolol, Bisoprolol. Start low, titrate to a resting heart rate of 55-60 bpm.

      • Calcium Channel Blockers (Second-line): e.g., Diltiazem or Amlodipine. Add to beta-blocker if symptoms persist.

      • Long-acting Nitrates: e.g., Isosorbide mononitrate. Use if beta-blockers/CCBs are contraindicated or not tolerated. Requires a nitrate-free interval.

    • B - Blood Pressure Control:

      • Target BP < 130/80 mmHg. ACE inhibitors (e.g., Perindopril) or ARBs (e.g., Losartan) are preferred, especially in patients with diabetes or LV dysfunction.

    • C - Cholesterol & Cigarettes:

      • High-intensity Statin: Atorvastatin 40-80mg or Rosuvastatin 20-40mg for all patients, regardless of baseline LDL. Target LDL < 1.4 mmol/L.

      • Smoking Cessation: Advise at every visit. Refer to smoking cessation clinics.

    • D - Diet & Diabetes Control:

      • Advise a heart-healthy diet. Refer to a dietitian.

      • Optimize glycemic control. Target HbA1c < 7%.

    • E - Education & Exercise:

      • Educate on the disease, medication adherence, and when to seek help.

      • Encourage regular, moderate-intensity exercise. Refer to cardiac rehabilitation programs.

VIII. Complications

  • Short-Term: Progression to Acute Coronary Syndrome (Unstable Angina or Myocardial Infarction). This is the main danger.

  • Long-Term:

    • Heart Failure: Due to recurrent ischemia causing left ventricular dysfunction.

    • Arrhythmias: Particularly ventricular tachycardia in the setting of severe ischemia.

    • Stroke: Shared risk factors (atherosclerosis).

IX. Prognosis

  • Prognosis depends heavily on LV function, severity of CAD, and control of risk factors.

  • With optimal medical therapy, the annual mortality rate is about 1-2%.

  • Top 3 Prognostic Factors:

    1. Left ventricular ejection fraction (LVEF).

    2. Extent and severity of coronary disease (e.g., left main or three-vessel disease).

    3. Number and severity of modifiable risk factors.

X. How to Present to Your Senior

(In the outpatient clinic)

"Dr, for your opinion please. This is Mr. Ahmad, a 58-year-old man with a background of T2DM and hypertension, who presents with a 3-month history of retrosternal chest tightness. It comes on when he walks to the mosque, about 200 meters, and is relieved by rest within 5 minutes. His symptoms are consistent with CCS Class II angina. His ECG is normal and his vitals are stable. My main differential is stable angina. I plan to start him on aspirin, a statin, and a beta-blocker, and refer him for an Exercise Stress Test. I would like your input on the plan."

XI. Summary & Further Reading

Now go and clerk your patients properly. Don't miss anything.

Danial Mirza
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