Symptomatic cerebral infarction following cardiac catheterization is rare but silent brain injury could occur at an unexpectedly high rate. One study has found that up to 22% of patients with severe aortic stenosis who have undergone retrograde catheterization of the valve can be identified as having new ischemic lesions as detected by diffusion-weighted (DW) magnetic resonance imaging (MRI). During cardiac catheterization, cerebral microembolism as detected by TCD has frequently been observed, but whether it is clinically relevant remains unknown . However, recent studies have suggested that some of these microemboli could be responsible for acute brain injury, as documented by DW MRI.

Indeed the high sensitivity of DW MRI suggests that this technique could allow an improved estimate of cerebral ischemic events associated with cardiovascular-catheter procedures. We therefore decided to perform DW MRI before and after cardiac catheterization to prospectively assess both clinically silent and apparent cerebral embolisms for the first time in a multicenter trial. Furthermore, a randomization between radial and femoral access will allow assessment of risk of silent brain injury associated with the different vascular access sites.

Inclusion Criteria:

• Patient with significant aortic valve stenosis before planned surgery.

Exclusion Criteria:

• Contraindication to MRI or inability to give written informed consent.

Patient with aortic stenosis