Clinical VignetteQuestion 1 of 23
Rupture Point
A 58-year-old man is brought to the emergency department because of 45 minutes of severe substernal chest pain radiating to his left arm. He also has shortness of breath, nausea, and diaphoresis. He has a 30-pack-year history of smoking and hypertension treated with lisinopril. His temperature is 37.0°C (98.6°F), pulse is 102/min, respirations are 20/min, and blood pressure is 155/95 mm Hg. Cardiac examination shows no abnormalities. An ECG shows ST-segment elevations in leads V2-V4. Serum troponin I concentration is 8.5 ng/mL (N <0.04). The patient undergoes emergency cardiac catheterization, which reveals complete thrombotic occlusion of the left anterior descending artery. Histopathologic examination of aspirated material shows a large lipid-rich necrotic core with dense macrophage infiltration throughout the lesion and minimal collagen deposition in the fibrous cap.
Which of the following features of this patient's atherosclerotic plaque best explains its susceptibility to rupture?