Normal Renal Artery Duplex Study in a Young Patient Without Hypertension
In a 23-year-old patient with no hypertension or kidney disease who has a completely normal bilateral renal artery duplex ultrasound showing no stenosis, normal kidney sizes, and normal renal-to-aortic ratios, no further diagnostic workup or intervention is indicated—this represents a normal study requiring only reassurance and routine follow-up.
Interpretation of Study Findings
The ultrasound demonstrates entirely normal parameters across all measured values:
Renal artery velocities and ratios are normal: The renal-to-aortic ratios of 1.52 (right) and 1.27 (left) are well below the diagnostic threshold of 3.5-3.7 for significant stenosis, and no elevated peak systolic velocities are reported 1, 2.
Kidney sizes are normal for age: Both kidneys measure within normal range (right 10.37 cm, left 11.77 cm), which is appropriate for a 23-year-old patient, as normal renal length is >10 cm in the third decade of life 1.
Vascular patency is confirmed: Both renal arteries show no stenosis at proximal, mid, or distal segments, and both renal veins are patent with normal intrarenal vascular perfusion 1, 2.
Clinical Context and Significance
This study was likely ordered to evaluate for secondary causes of hypertension or renal dysfunction, but the patient has neither condition:
Renovascular hypertension is extremely unlikely: Renal artery stenosis as a cause of renovascular disease has specific clinical features including severe hypertension (diastolic >110 mm Hg), new onset hypertension in young adults <35 years, abdominal bruit, or refractory hypertension—none of which apply to this normotensive patient 1.
No evidence of renal vascular disease: The study excludes renal artery stenosis, thrombosis, or venous thrombosis, which are rare causes of acute kidney injury (representing only 1-1.5% of cases even in high-risk populations) 1, 3.
Recommended Management
No further vascular imaging or intervention is warranted based on these completely normal findings:
Reassurance is appropriate: The patient has no anatomic or hemodynamic abnormalities of the renal vasculature 1, 2.
Routine clinical follow-up only: Monitor blood pressure and renal function through standard primary care, with no need for repeat vascular imaging unless new clinical symptoms develop 1.
Do not pursue additional imaging: CT angiography, MR angiography, or conventional angiography are not indicated when duplex ultrasound is technically adequate and shows normal findings 1, 2.
Important Caveats
While this study is reassuring, recognize these limitations:
Technical quality was adequate but challenging: The study notes difficulty due to body habitus, which can occasionally result in false-negative results for stenosis 1, 2, 4. However, in a young normotensive patient with no clinical suspicion for renovascular disease, the pretest probability is extremely low, making false-negative results clinically irrelevant.
Duplex ultrasound can miss stenosis in difficult cases: In patients with high clinical suspicion (severe hypertension, flash pulmonary edema, acute kidney injury with ACE inhibitors), a negative ultrasound does not definitively exclude stenosis and may require confirmatory CTA or MRA 2, 5, 4. This does not apply to the current asymptomatic patient.
Do not repeat imaging without new symptoms: Future imaging should only be considered if the patient develops hypertension, declining renal function, or other clinical features suggestive of renovascular disease 1, 2.