A 56-year-old man comes to the clinic for a routine checkup. Medical history includes hypertension, type 2 diabetes mellitus, hyperlipidemia, and mild intermittent asthma. The patient currently takes no medications and has not seen a physician in 7 years. He reports feeling well. Blood pressure is 152/101 mm Hg and pulse is 87/min. Waist circumference is 110 cm (43 in). Laboratory results are as follows:
| Low-density lipoprotein | 161 mg/dL |
| Fasting blood glucose | 201 mg/dL |
| Hemoglobin A1c | 7.4% |
Which of the following vascular beds is most likely to carry the highest atherosclerotic burden in this patient?
Show Explanatory Sources
This patient has multiple risk factors (eg, hypertension, diabetes mellitus, hyperlipidemia) that contribute to atherosclerosis. Atherosclerosis is a pathophysiologic process that begins in childhood with the development of focal intimal thickening due to accumulation of lipid-laden macrophages and extracellular matrix ("fatty streaks"). With advancing age, fatty streaks transition into atherosclerotic plaques, such as fibrous cap atheromas and fibrous plaques. More advanced lesions develop a lipid-rich necrotic core and areas of calcification.
Atherosclerosis is a chronic disease of the arterial walls and involves all major vascular beds. The most susceptible vascular regions involve bends and branch points that encourage turbulent blood flow, which disrupts vascular wall integrity and leads to endothelial cell dysfunction. Turbulent blood flow also leads to prolonged endothelial contact with cholesterol particles.
The hemodynamics of the lower abdominal aorta and the coronary arteries make these vascular beds the most susceptible to atherosclerosis of all the major vascular beds in the body. In fact, atherosclerotic lesions (eg, intimal thickening, fatty streaks) occur in these vessels as early as the second decade of life.
(Choice B) The internal thoracic arteries (previously known as the internal mammary arteries) are relatively resistant to developing atherosclerosis and are often used as conduits in patients undergoing coronary artery bypass grafting.
(Choices C and E) The mesenteric and renal arteries are susceptible to developing atherosclerosis; however, the burden of disease tends to be less severe than in the coronary circulation.
(Choice D) Along with the carotid arteries, the popliteal arteries are among the most susceptible to atherosclerosis in the body. However, these arteries are not as susceptible to atherosclerosis as the aorta and coronary arteries.
Educational objective:
Atherosclerosis is a pathophysiologic process involving endothelial cell dysfunction, and it develops most rapidly in areas with bends and branch points that encourage turbulent blood flow. The lower abdominal aorta and coronary arteries are the vascular beds most susceptible to atherosclerosis; they tend to develop atherosclerosis earliest in life and have the highest overall atherosclerotic burden.