Rationale and study design for one-stop assessment of renal artery stenosis and renal microvascular perfusion with contrast-enhanced ultrasound for patients with suspected renovascular hypertension

Background: Renal artery stenosis (RAS) is always associated with abnormalities in renal microvascular perfusion (RMP). However, few imaging methods can simultaneously evaluate the degree of luminal stenosis and RMP. Thus, this study will aim to evaluate the feasibility of using contrast-enhanced ultrasound (CEUS) for assessing both RAS and RMP to achieve a one-stop assessment of patients with suspected renovascular hypertension. Methods: This will be a single-center diagnostic study with a sample size of 440. Patients with chronic kidney disease (CKD) and suspected of having resistant hypertension will be eligible. Patients with Stages 1–3 CKD will undergo CEUS and computed tomography (CT) angiography (CTA). Values obtained by CEUS and CTA for diagnosing low-grade (lumen reduced by <60%) and high-grade (lumen reduced by ≥60%) RAS will be compared. Moreover, all patients will also undergo radionuclide imaging. The diagnostic value for RAS will be assessed by the receiver operating characteristic curve, including the accuracy, sensitivity, specificity, positive predictive values, negative predictive values, and area under the ROC. Pearson correlation analysis will be performed to assess the association between CEUS findings for RMP and glomerular filtration rate measured by a radionuclide imaging method. Conclusion: The data gathered from this study will be used to evaluate the feasibility of expanding clinical applications of CEUS for evaluation of patients with suspected renovascular hypertension. Trial Registration: Chinese Clinical Trial Registry, ChiCTR1800016252; https://www.chictr.org.cn. Key words: Renovascular hypertension; contrast-enhanced ultrasound; renal artery stenosis; renal microvascular perfusion