A 61-year-old man presents to his primary care physician because of chest discomfort that has occurred intermittently over the past 8 months. He describes a pressure-like sensation in the center of his chest that develops when he walks uphill from the parking lot to his office or climbs two flights of stairs. The discomfort does not occur at rest and typically resolves within 3–5 minutes of stopping the activity. He denies nausea, diaphoresis, palpitations, syncope, or shortness of breath at rest. His medical history is significant for hypertension, hyperlipidemia, and type 2 diabetes mellitus. Medications include lisinopril, metformin, and atorvastatin. He smoked one pack of cigarettes daily for 25 years before quitting 10 years ago. Temperature is 36.8°C (98.2°F), blood pressure is 138/82 mm Hg, pulse is 74/min, and respiratory rate is 14/min. BMI is 31 kg/m². Cardiopulmonary examination is unremarkable. Resting ECG demonstrates normal sinus rhythm without ST-segment abnormalities.
Which of the following is the most likely explanation for this patient's symptoms?
The correct answer is:
C) Fixed atherosclerotic coronary artery narrowing causing demand ischemia
This patient has stable angina, which is characterized by predictable chest discomfort that occurs with exertion or emotional stress and resolves with rest or nitroglycerin. The underlying mechanism is a fixed atherosclerotic narrowing of a coronary artery that limits blood flow during periods of increased myocardial oxygen demand. At rest, coronary perfusion is sufficient, but during exertion the stenotic vessel cannot adequately increase blood flow, resulting in transient myocardial ischemia and chest pain.
Several features of this vignette strongly support stable angina. His symptoms have been present for months, occur at a reproducible level of exertion, and resolve promptly with rest. If cardiac biomarkers such as high-sensitivity troponin were checked, they should be normal. In addition, he has multiple risk factors for atherosclerotic cardiovascular disease, including diabetes, hypertension, hyperlipidemia, obesity, and a prior smoking history.
Stable angina is one manifestation of chronic coronary artery disease. Initial evaluation often includes stress testing or coronary imaging in appropriate patients, along with aggressive risk-factor modification. Treatment typically includes antiplatelet therapy, statins, lifestyle interventions, and antianginal medications such as beta blockers or nitrates.
A high-yield Step 2 distinction is that stable angina results from a fixed obstruction, whereas acute coronary syndromes result from plaque rupture and thrombosis.
Answer choice A: Acute plaque rupture with complete coronary artery occlusion, is incorrect.
Acute plaque rupture with complete coronary occlusion causes ST elevation myocardial infarction (STEMI). Patients typically present with prolonged chest pain that occurs at rest and is accompanied by ECG changes and elevated cardiac biomarkers. This patient's symptoms are chronic, predictable, and exclusively exertional.
Answer choice B: Coronary vasospasm causing transient myocardial ischemia, is incorrect.
Coronary vasospasm (vasospastic or Prinzmetal angina) usually causes episodic chest pain at rest, often occurring during the night or early morning. Transient ST-segment elevation may be present during episodes. This patient's exertional and reproducible symptoms are more consistent with stable angina.
Answer choice D: Inflammation of the pericardium causing pleuritic chest pain, is incorrect.
Acute pericarditis typically causes sharp, pleuritic chest pain that worsens with inspiration and improves when sitting forward. The exertional chest pressure described here is not characteristic of pericardial inflammation.
Answer choice E: Pulmonary embolism causing acute right ventricular strain, is incorrect.
Pulmonary embolism generally presents with acute-onset dyspnea, pleuritic chest pain, tachycardia, hypoxemia, or syncope. The chronic, reproducible exertional symptoms in this vignette are much more suggestive of coronary artery disease.
Key Learning Point
Stable angina is caused by fixed atherosclerotic narrowing of a coronary artery that limits myocardial blood flow during exertion. Symptoms are predictable, occur with increased oxygen demand, and resolve with rest or nitroglycerin.
