Title:
Epidemiology of Ultrasound-based Surveillance in Post-kidney Transplant Recipients: A Systematic Review of the Evidence BASE and the U.S. Research Gap (2016–2026)

Authors:
Prince Acheampong & Fuseina Habib, USA

Abstract:

Introduction: Kidney transplantation is the most effective treatment for end-stage renal disease, with 27,759 transplants performed in the United States in 2024. Graft failure affects 20–30% of recipients within 10 years. Doppler ultrasound is the mandated first-line imaging modality under AIUM and ACR standards, yet evidence linking ultrasound-derived parameters to long-term graft outcomes remains inconsistent and predominantly derived from non-U.S. cohorts.

Methods: To systematically review epidemiologic evidence examining associations between Doppler ultrasound parameters and graft survival, graft function, and patient outcomes in kidney transplant recipients, with attention to U.S.-based study representation from 2016 to 2026. A structured search was conducted across PubMed/MEDLINE, PubMed Central (PMC), Embase, CINAHL, ScienceDirect, Wiley Online Library, and federal repositories (USRDS, HRSA/OPTN, AIUM/ACR) for studies reporting resistive index (RI), peak systolic velocity (PSV), and end-diastolic velocity (EDV) and their associations with delayed graft function, graft survival, or patient mortality in adult recipients.

Results: Twenty(20) sources met inclusion criteria (13) peer-reviewed studies and seven federal surveillance/guideline sources). Of the thirteen(13) peer-reviewed studies, Nine(9) originated from non-U.S. institutions and four were U.S.-based, of which only two were single-center primary studies. Resistive index elevations above 0.70–0.80 were consistently associated with adverse outcomes, though methodological heterogeneity precludes definitive threshold standardization. Evidence on PSV and EDV, including transplant renal artery stenosis (TRAS) diagnostic thresholds, was limited in U.S. cohorts.

Conclusion: Doppler parameters demonstrate consistent associations with adverse post-transplant outcomes internationally. U.S.-based population-level data from centers operating under AIUM and ACR standards remains critically absent, representing an urgent national research priority.

DOI: http://dx.doi.org/10.51505/ijmshr.2026.10407