Makindo Medical Notes

Unstable Angina is an acute coronary syndrome in which myocardial ischemia occurs due to partial or intermittent coronary artery obstruction, but without myocardial necrosis (i.e., no troponin rise). It lies between stable angina (predictable, exertional) and NSTEMI. Prompt recognition and management reduce the risk of myocardial infarction and death.

🧬 Pathophysiology

• Rupture or erosion of an atherosclerotic plaque → exposure of subendothelial tissue → platelet aggregation and thrombus formation.
• The thrombus causes partial or transient occlusion → ischemia under increased demand or at rest.
• No full-thickness necrosis → normal troponin initially (if tested early); may remain normal even on serial testing.
• Other contributory mechanisms: coronary spasm, endothelial dysfunction.

📊 ECG Features

• May be completely normal, especially when pain-free.
• Transient ST-segment depression (horizontal or down-sloping) during ischemic episodes.
• Dynamic T-wave inversion, which may resolve with relief of ischemia.
• No persistent ST elevation (that would suggest STEMI).
• Repeat ECGs, especially during pain, are essential.

🩺 Clinical Features / Presentation

• Chest pain at rest or on minimal exertion; often increasing in frequency or duration (crescendo angina).
• Pain may last >20 minutes, may radiate to jaw/arm/back.
• Typical triggers include cold, exertion, emotional stress.
• Associated symptoms: sweating, nausea, dyspnoea, feelings of impending doom.
• No significant troponin elevation, by definition; biomarkers negative/normal.

🧪 Investigations

• 12-lead ECG immediately; repeat if chest pain recurs.
• Serial troponin measurements (e.g. at 0 and 3-6 hours) to exclude NSTEMI.
• Baseline bloods: FBC, U&E, glucose, lipid panel, coagulation.
• CXR if suspicion of other pathology (e.g. pneumonia, aortic dissection).
• Echocardiogram: assess ventricular function, wall motion abnormalities if needed.
• Use risk scores (TIMI, GRACE) to guide prognosis and management strategy.

🛠️ Management of Unstable Angina

• 🚑 Immediate Medical Therapy
  • 💊 Aspirin: 300 mg PO stat → then 75 mg OD lifelong.
  • 💊 P2Y₁₂ inhibitor: Ticagrelor 180 mg stat (preferred) OR Clopidogrel 300–600 mg.
  • 🩸 Anticoagulation: Fondaparinux 2.5 mg SC OD (unless immediate PCI). 🔄 Alternatives: Enoxaparin or UFH if PCI planned.
  • 🌬️ Nitrates: GTN spray/SL for pain; IV GTN infusion if persistent (SBP >110 mmHg).
  • 🧯 Analgesia: Morphine IV + antiemetic (e.g. metoclopramide).
  • 🫀 Beta-blocker: Metoprolol PO (avoid in asthma, hypotension, bradycardia, LVF).
  • 🧴 Statin: High-intensity statin (e.g. atorvastatin 80 mg stat).
  • 💊 ACE inhibitor/ARB: Start once haemodynamically stable (esp. LV dysfunction, HTN, diabetes).
  • 📊 Risk Stratification & Invasive Strategy
    • ⚡ Immediate angiography (<2h): Haemodynamic collapse, refractory angina, arrhythmias, cardiogenic shock.
    • 🕐 Early invasive (<24h): GRACE >140, recurrent pain, dynamic ST/T changes, troponin rise (if NSTEMI).
    • 📅 Within 72h: Diabetes, renal impairment, prior PCI/CABG, LVEF <40%.
    • ✅ Conservative: If low risk and pain resolved → optimise medical therapy, plan outpatient CTCA.
  • 🌱 Secondary Prevention (Long-term)
    • 💊 DAPT: Aspirin + P2Y₁₂ inhibitor for 12 months (review bleeding risk).
    • 🧴 Statin: Lifelong high-intensity (e.g. atorvastatin 80 mg nocte).
    • 💊 ACEi/ARB: Indefinite in LV dysfunction, diabetes, or hypertension.
    • 🫀 Beta-blocker: Lifelong if LV dysfunction or post-MI.
    • 🧪 Aldosterone antagonist: If EF <40% + HF or diabetes.
    • 🚭 Lifestyle: Stop smoking, adopt Mediterranean diet, 150 min exercise/week, weight control.
    • 🏥 Rehabilitation: Refer to cardiac rehab programme for education, exercise, and psychosocial support.
• Risk Stratification & Invasive Strategy
  • Identify high-risk features: ongoing chest pain, dynamic ECG changes, elevated risk scores (GRACE >140), haemodynamic instability.
  • Patients with high-risk features → early invasive strategy (angiography ± PCI) typically within 24 h.
  • Lower-risk → conservative management (medical therapy + outpatient or delayed angiography).
• Secondary Prevention / Long-Term Management
  • Dual antiplatelet therapy (DAPT) for ~12 months, unless bleeding risk too high.
  • Lifelong high-intensity statin therapy.
  • Control of cardiovascular risk factors: smoking cessation, BP control, lifestyle modifications (diet, exercise).
  • Beta-blocker and ACEi in patients with LV dysfunction or previous MI.
  • Enroll in cardiac rehabilitation.

⚠️ Prognosis & Risk of Progression

• Without treatment, UA has a considerable risk of progressing to NSTEMI or STEMI (approx. 10–20% in 30 days in high-risk patients).
• Early invasive management in high risk improves outcomes (reduced mortality, reduced recurrent MI).
• Long-term prognosis depends heavily on risk factor management and adherence to therapy.

📌 Exam Pearls

• UA = chest pain + dynamic ECG changes + negative troponins.
• Normal ECG does NOT exclude UA.
• TIMI / GRACE risk scores are very useful and often asked about.
• Management of UA ≈ NSTEMI in many guidelines (medical therapy + invasive in high risk).
• Always consider patient comorbidities (renal impairment, bleeding risk) when choosing therapy.

📚 References

• NICE Clinical Guideline: Management of Acute Coronary Syndromes.
• ESC Guidelines for Non-ST Elevation ACS.
• Recent trials / meta-analyses on UA vs NSTEMI outcomes.

❤️ Case 1 — New-Onset Angina at Rest

A 64-year-old man with hypertension and smoking history presents with crushing central chest pain occurring unpredictably at rest over the past 24 hours. ECG shows no ST elevation, and troponins are negative. 💡 Unstable angina represents an acute coronary syndrome where plaque rupture and thrombus cause critical ischaemia without myocardial necrosis. It is a high-risk state for infarction. Management includes hospital admission, dual antiplatelet therapy, anticoagulation, and early coronary angiography.

❤️ Case 2 — Crescendo Angina

A 70-year-old woman with known stable angina reports chest tightness now occurring after walking just 50 yards, whereas previously she managed half a mile. Pain is also more prolonged and occurs at night. ECG is unremarkable, and troponins remain normal. 💡 Crescendo angina is defined by worsening frequency, severity, or duration of anginal episodes, signalling unstable plaque and risk of progression to MI. Management parallels other ACS: aggressive risk factor modification, dual antiplatelet therapy, and urgent cardiology input.