A 58-year-old man with a 20-year history of smoking, hypertension, and dyslipidemia presents with exertional chest pain. Physical examination reveals an early diastolic murmur. You suspect coronary atherosclerosis with aortic regurgitation. Which investigation is most appropriate to directly visualize the atherosclerotic lesion and assess the degree of luminal stenosis?

Explanation

## Investigation of Choice for Coronary Atherosclerosis Visualization ### Why Coronary Angiography is Correct **Key Point:** Coronary angiography is the gold standard for direct visualization of atherosclerotic plaques and quantification of luminal stenosis in coronary arteries. It provides real-time, high-resolution imaging of the coronary tree and allows assessment of lesion morphology, calcification, and flow characteristics. **High-Yield:** Coronary angiography is the only investigation that: - Directly visualizes atherosclerotic lesions - Quantifies the degree of stenosis (percent diameter reduction) - Identifies the exact location and number of lesions - Guides interventional decisions (PCI vs. CABG vs. medical management) - Allows assessment of collateral circulation ### Comparison of Atherosclerosis Investigations | Investigation | Purpose | Sensitivity | Specificity | Direct Visualization | |---|---|---|---|---| | **Coronary angiography** | Direct lesion visualization & stenosis quantification | 95–99% | 95–99% | **Yes** | | Carotid IMT ultrasound | Subclinical atherosclerosis screening | Moderate | Moderate | No (surrogate marker) | | hs-CRP | Inflammatory marker; risk stratification | Low specificity | Low specificity | No (biomarker) | | CAC scoring | Calcified plaque burden; risk assessment | Moderate | Moderate | No (indirect; calcium only) | **Clinical Pearl:** Coronary angiography is invasive but remains the reference standard because it is the only modality that directly shows the atherosclerotic lesion, its composition, and its hemodynamic significance. It is the investigation of choice when therapeutic intervention (PCI) is anticipated. **Tip:** In NEET PG, when a question asks for the investigation to "directly visualize," "confirm," or "assess the degree of stenosis," the answer is coronary angiography for coronary disease and carotid duplex ultrasound for carotid disease. [cite:Robbins 10e Ch 11]