Renal artery angiography: "the right ipsilateral oblique" myth

Finding the optimal image intensifier angle of obliquity during renal intervention is important for accurate stent placement but can require multiple catheter rotations and test injections of contrast.

Explore the usefulness of axial magnetic resonance angiography (MRA) as a roadmap for predicting image intensifier position during subsequent renal intervention.

MRA images were reviewed in 137 consecutive patients (255 renal arteries) undergoing workup for renal artery stenosis. The axial angle of renal artery incidence perpendicular to the spine was estimated by two operators and results averaged.

The average angle of incidence for the renal artery ostia was +21.24 degrees +/-2.31 degrees for the right and +8.81 degrees +/-2.0 degrees for the left (P < .0001). The positive numbers correlate with left anterior oblique (LAO) and negative right anterior oblique (RAO).

MRA can be used to define the origin of the renal artery and is most likely to predict an LAO image window for subsequent angiography of the left and right renal arteries displacing the "ipsilateral oblique" axiom. In patients without baseline MRA the 10 to 20 degree LAO "empiric" position will allow coaxial imaging of both renal ostia in 75% of cases. However, there can be extreme variation in the renal origin (53 degrees RAO to 85 degrees LAO) and we advocate using the simple technique reported herein to define the renal origin in patients with pre-procedure MRA.