Special Case Series: Renal artery stenosis can be difficult to diagnose when heart disease changes the entire Doppler waveform.

This advanced teaching case examines a 74-year-old patient with resistant hypertension, worsening renal function, ischemic cardiomyopathy, reduced cardiac output, moderate aortic stenosis, and atrial fibrillation.

Why this case matters

• Low cardiac output may reduce renal and aortic velocities.
• Atrial fibrillation produces beat-to-beat variation in PSV, EDV, and acceleration.
• Aortic stenosis may create bilateral delayed systolic upstrokes that resemble tardus-parvus waveforms.
• A very low aortic PSV may artificially elevate the renal-aortic ratio.
• A focal velocity step-up, post-stenotic turbulence, and unilateral downstream delay help reveal true renal artery stenosis.

The complete eight-page case includes the clinical presentation, scanning protocol, Doppler measurements, cardiac confounders, diagnostic reasoning, suggested report, differential diagnosis, quality-control checklist, and ARDMS-style review questions.

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Prepared by Dr. Godefroy A. Watchiba, MD, RDMS, RVT. This fictional, de-identified composite case is provided for education and does not replace local laboratory criteria, physician interpretation, or patient-specific medical care.