The prevalence and significance of renal perfusion defects in early kidney transplants quantified using 3D contrast enhanced ultrasound (CEUS).

OBJECTIVES

Vascular complications are one of the most common causes of early kidney transplant dysfunction. Contrast enhanced ultrasound increases sensitivity to vascular changes. The aim of this study was to assess the prevalence and size of vascular abnormalities in early renal transplants using 3D CEUS and the significance of perfusion defects on renal function.

METHODS

Ninety-nine renal transplant patients underwent 3D CEUS after surgery to quantify perfusion defects as percentage total renal volume (TRV). Serum creatinine and estimated glomerular filtration rate (eGFR) were recorded up to 3 months post-surgery.

RESULTS

Twenty participants had focal perfusion defects (0.2-43%TRV). There was a meaningful difference in patients with perfusion defects in eGFR at 1 month (90% CI 2.7-19.2 mL/min/1.73 m2) and 3 months (90% CI 1.9-19.6 mL/min/1.73 m2) and creatinine at 3 months (90% CI -56 - -8 μmol/L) using a predetermined clinical threshold. Perfusion defect size correlated well with both serum creatinine and eGFR at 3 months (R = 0.80, p ≤ 0.000 and 0.58, p = 0.038). No correlation was seen prior to 3 months.

CONCLUSIONS

Perfusion defects in kidney transplants were more common than expected and were highly likely to reduce renal function at 1-3 months, and the size of the defect affected the degree of functional change at 3 months.

KEY POINTS: • Perfusion defects were more common than previously thought. • Perfusion defects could be quantified using 3D CEUS. • The presence of even small perfusion defects may affect kidney function. • Size of perfusion defects correlated with subsequent kidney function at 3 months. • Potentially useful in informing clinician expectations of kidney function post-surgery.