A 75-year-old woman was referred to cardiology for evaluation for dizziness. She complains of intermittent dizziness for a year not related to position change, as well as progressive dyspnea on exertion when she walks 50 feet. If she persists, she develops throat and bilateral arm discomfort that quickly resolves with rest. Symptoms have progressed over the past 3 months, with decreased exercise capacity.

A comprehensive evaluation for her dizziness included evaluation of her cerebrovascular anatomy, which showed antegrade vertebral artery flow bilaterally without stenosis and mild left internal and severe right internal carotid stenosis. She has no stroke-like symptoms.

Her past medical history includes hypertension, hypercholesterolemia, severe pulmonary fibrosis requiring home oxygen, and peripheral arterial disease treated with bilateral lower extremity percutaneous intervention.

Current medications include amlodipine, benazepril, aspirin, atorvastatin, omeprazole, prednisone, and albuterol inhaler. She has no known drug allergies.

She is a former insurance agent who does not consume alcohol or use recreational drugs. She smoked 2 packs of cigarettes a day for 25 years and quit 20 years ago.

Her mother died of a myocardial infarction at age 63. Her father died of natural causes in his 80s.

Electrocardiography showed normal sinus rhythm with left atrial enlargement. A transthoracic echocardiogram showed preserved left ventricular systolic function with an estimated ejection fraction of 60% to 65%, mild concentric left ventricular hypertrophy, and moderate left atrial enlargement. No significant valvular heart disease was noted.

MANAGEMENT

Since the pretest probability of obstructive coronary artery disease (CAD) was high, coronary angiography was performed. The left main coronary artery had a severely calcified stenosis that was treated with rotational atherectomy and provisional drug-eluting stent placement into the proximal left anterior descending artery (Figures 14-1, 14-2, 14-3, 14-4). Orbital atherectomy is an alternative option to facilitate stent delivery (Figures 14-5 and 14-6).

Coronary artery calcification (CAC) is age and sex dependent and is apparent in most individuals older than 70 years (≥90% of men and ≥67% of women).^1,2 CAC strongly correlates with atherosclerotic burden and cardiac event rate.^3,4 It results in decreased vessel compliance and, when associated with a flow-limiting stenosis, limits myocardial perfusion.^5,6 In patients undergoing revascularization, CAC adversely impacts procedural outcomes. In a pooled analysis of 6855 patients presenting with acute coronary syndrome, heavy coronary calcification was independently associated with definite stent thrombosis (hazard ratio [HR], 1.62; 95% confidence interval [CI], 1.14-2.30; P = .007) and ischemic target lesion revascularization (HR, 1.44; 95% CI, 1.17-1.78; P = .0007).^7,8 Coronary calcification may prevent adequate stent expansion, thus resulting in an elevated risk of stent thrombosis (Figures 14-7, 14-8, 14-9, 14-10). Computed tomography scan–based calcium scores independently predict cardiac death and myocardial infarction, especially in those at intermediate risk for cardiovascular disease.^9,10 In the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study, multivessel intravascular ultrasound (IVUS) was performed, and patients with the highest calcium volumes had the highest 3-year major adverse cardiac event (MACE) rates.^11,12

Coronary calcification can be identified on coronary angiography or intravascular imaging (IVUS or optical coherence tomography [OCT]) (Table 14-1).^13-15 IVUS has a sensitivity of 90% to 100% and specificity of 99% to 100% for CAC detection.¹³ On IVUS, CAC appears as a bright echodense arc with acoustic shadowing (see Figure 14-1).¹³