Compression of renal arteries by the diaphragmatic crus: proposal for a new classification

Objective: Renal artery entrapment (RAE) is a rare cause of hypertension, and its management remains debated between surgical and endovascular approaches. The aim of this study was to propose an updated classification of RAEs. Design and method: This retrospective study included all patients referred to our center between 1995 and 2021 with a diagnosis of RAE confirmed by CT scan. The primary objective was to describe the type of renal artery (RA) compression (ostial or truncular location and focal or long extension). The association between the type of compression and age, side of compression and high origin of the RA was also evaluated. Results: Forty patients with 45 RAE were included. The compression was focal and ostial in 22 arteries (49%), long and truncular in 13 RA (29%) and focal and truncular in 10 RA (22%), of which 2 RA (4%) originated from the thoracic aorta with a transdiaphragmatic passage. From this distribution, an updated classification with 4 types of RAE was proposed including: type 1: ostial compression, type 2: long truncular compression, type 3: focal truncular entrapment and type 4: truncular entrapment with intrathoracic RA origin. There was no association between the type of RAE and the patient's age (p = 0.09) or the side of compression (p = 0.42). Type 2 and type 4 RAEs were associated with a higher origin of the compressed artery (p = 0.04). Conclusions: This study proposed an updated classification of RAE with four type of compressions. Knowledge of these conditions may be helpful for a future treatment algorithm.