A 72-year-old man has blood pressure recordings of 168/64 mmHg on repeated visits. Cardiac output and renal function are normal. The most likely hemodynamic mechanism of this pattern is:

• A Increased circulating catecholamines
• B Decreased aortic compliance ✓
• C Increased total peripheral resistance with normal aorta
• D Aortic valve stenosis

Explanation

With aging, elastin in the proximal aorta is replaced by stiffer collagen, reducing the Windkessel buffering of systolic ejection. Systolic pressure therefore rises while diastolic pressure falls because elastic recoil during diastole is weaker, producing isolated systolic hypertension with a wide pulse pressure. Increased peripheral resistance raises both systolic and diastolic pressures proportionally. Catecholamine excess would raise diastolic pressure as well. Aortic stenosis produces a slow-rising low-amplitude carotid pulse, not this pattern.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.