Regarding the pathophysiology and management of NSTEMI and unstable angina, all of the following are true EXCEPT:

## Distinguishing NSTEMI from Unstable Angina **Key Point:** The cardinal difference between NSTEMI and unstable angina is the presence or absence of myocardial necrosis, detected by elevated cardiac biomarkers (troponin, CKMB). ### Pathophysiology Both conditions result from **partial coronary occlusion** (usually from plaque rupture with superimposed thrombosis) that allows some distal perfusion. This contrasts with STEMI, where complete occlusion causes transmural infarction. ### Biomarker Distinction | Feature | Unstable Angina | NSTEMI | |---------|-----------------|--------| | **Symptoms** | Chest pain at rest or with minimal exertion | Same as UA | | **ECG** | No ST elevation; may have T-wave changes or be normal | ST depression, T-wave inversion, or dynamic changes | | **Troponin** | **Normal** | **Elevated** | | **Diagnosis** | Clinical + ECG (no biomarker rise) | Clinical + ECG + elevated troponin | **High-Yield:** Troponin elevation is the **only** biochemical marker that separates NSTEMI from unstable angina. ### Dual Antiplatelet Therapy (DAPT) **Clinical Pearl:** DAPT with aspirin + P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor) is **standard of care** in BOTH unstable angina AND NSTEMI. This is a cornerstone of acute coronary syndrome management. **Why the distractor is wrong:** The statement "DAPT is contraindicated in unstable angina" is **false**. DAPT is indicated in both conditions and reduces recurrent ischemic events. ### Medical Management Common to Both 1. **Beta-blockers** — reduce heart rate, contractility, and myocardial oxygen demand; reduce anginal frequency and reinfarction risk 2. **ACE inhibitors** — reduce afterload and improve ventricular remodeling 3. **Statins** — plaque stabilization and anti-inflammatory effects 4. **Anticoagulation** — unfractionated heparin or LMWH to prevent thrombotic extension 5. **Nitrates** — symptom relief (but no mortality benefit) **Mnemonic: ABCDE of ACS management** — **A**spirin + Anticoagulation, **B**eta-blockers, **C**oronary angiography, **D**ual antiplatelet therapy, **E**nzyme inhibitors (ACE-I) and statins. ## Why Each Distractor Is Correct - **Option 0:** Elevated troponins are the biochemical hallmark of NSTEMI and distinguish it from unstable angina — **TRUE**. - **Option 1:** Both UA and NSTEMI result from partial occlusion with preserved distal flow — **TRUE**. - **Option 3:** Beta-blockers are first-line agents in both conditions for symptom relief and prognostic benefit — **TRUE**. [cite:Harrison 21e Ch 297]