Chronic stable angina pectoris: Overview

A 47-year-old man reports a six-month history of intermittent chest discomfort while playing squash. He describes lower substernal tightness with numbness of the left upper arm only during exertion. He does not smoke. His father died suddenly at the age of 49 years. His blood pressure is 138/84 mm Hg. The level of total cholesterol is 261 mg per deciliter (6.7 mmol per liter), of low-density lipoprotein cholesterol 172 mg per deciliter (4.4 mmol per liter), and of high-density lipoprotein cholesterol 50 mg per deciliter (1.3 mmol per liter), and the triglyceride level is 113 mg per deciliter (2.9 mmol per liter). The result of an exercise test is positive, with pain and 1.5 mm of horizontal ST-segment depression at stage 4 of the Bruce protocol. How should the patient's case be managed?

The Clinical Problem

The diagnosis of chronic stable angina pectoris includes predictable and reproducible left anterior chest discomfort after physical activity, emotional stress, or both; symptoms are typically worse in cold weather or after meals and are relieved by rest or sublingual nitroglycerin. The presence of one or more obstructions in major coronary arteries is likely; the severity of stenosis is usually greater than 70 percent.

Pathophysiology

Angina occurs when there is regional myocardial ischemia caused by inadequate coronary perfusion and is usually but not always induced by increases in myocardial oxygen requirements. Cardinal features of chronic stable angina include complete reversibility of the symptoms and repetitiveness of the anginal attacks over time, typically months to years. New, prolonged, or recent-onset symptoms are characteristic of unstable angina. Coexisting conditions, such as poorly controlled hypertension, anemia, or Thyrotoxicosis, can precipitate or accentuate angina.

As coronary atherosclerosis progresses, there is deposition of plaque external to the lumen of the artery; the plaque may extend eccentrically and outward without compromising the lumen. Thus, stress testing or angiography may not suggest coronary disease, even in the presence of significant Atherosclerosis. As Atherosclerosis worsens, encroachment of the plaque mass into the lumen can result in hemodynamic obstruction and angina1. Disordered endothelial vasomotor function of the coronary arteries is common in patients with angina and results in diminished vasodilatation or even vasoconstriction in response to various stimuli, including exercise. Occasionally, patients with severe aortic-valve disease or hypertrophic cardiomyopathy have angina-like chest pain in the absence of overt coronary disease.