Relevance of Pressure Recovery in a Young Patient With Aortic Stenosis and Small-Caliber Aorta

TL;DR

A young patient with aortic stenosis had falsely high valve pressure readings due to a phenomenon called pressure recovery, which was corrected with invasive measurements.

Contribution

This case highlights the importance of recognizing pressure recovery in small aortas to avoid misdiagnosis of severe aortic stenosis.

Findings

Doppler echocardiography overestimated the severity of aortic stenosis due to pressure recovery in a small aorta.

Invasive measurements confirmed a moderate aortic stenosis after correcting for pressure recovery.

Angina was caused by a high-grade stenosis in the left anterior descending artery, not the aortic valve.

Abstract

The case concerns a 20-year-old patient with Canadian Cardiovascular Society class II angina who was initially referred for aortic valve replacement because of a suspected high-grade aortic valve stenosis with increased transvalvular gradients (max/mean: 70/40 mm Hg) measured by Doppler echocardiography. Examinations using transesophageal echocardiography and computed tomography showed a sufficiently opening bicuspid aortic valve, excluded supra- and subvalvular stenoses, and measured a narrow aorta (diameter: 2 cm). The explanation for the highly increased gradients across the aortic valve was the pressure recovery (PR) phenomenon, which cannot be detected by Doppler gradients. Distal to a stenosis kinetic energy is converted back into potential energy, most effectively in small aortas (area: <3 cm2). This reduces the actual transvalvular pressure gradient, which can directly be determined with cardiac catheterization. Accordingly, invasive measurements showed a moderate aortic stenosis (mean transvalvular pressure: 19 mm Hg), almost identical to the PR-corrected Doppler measurements. A high-grade stenosis of the proximal left anterior descending artery was treated interventionally, which could explain the angina symptoms.

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