Following carotid intervention, the number of detectable diffusion-weight magnetic resonance imaging (DW-MRI) lesions is an order of magnitude greater than adverse clinical event (stroke/death). This lends credence to the use of DW-MRI as a surrogate endpoint allowing comparisons of interventional strategies in studies with reduced sample size, wrote Sumaira Macdonald, Newcastle, UK. She discussed this topic at CX35 on Tuesday 9 April.
By Sumaira Macdonald
The International Carotid Stenting Study (ICSS) sub-study comparing DW-MRI lesions in patients undergoing largely filter-protected carotid stenting and carotid endarterectomy demonstrated significantly fewer DW-MRI lesions after carotid endarterectomy, implying superior of control of procedural microemboli. Sixty-two of 124 (50%) patients undergoing distal filter-protected transfemoral carotid artery stenting and 18 of 107 patients undergoing carotid endarterectomy (17%) had new DW-MRI lesions (p<0.0001). Individual lesions were smaller in the carotid artery stenting group than in the carotid endarterectomy group (p<0.0001). Of the DW-MRI positive scans following carotid artery stenting, 25 (34%) resulted from unprotected carotid artery stenting and 37 (75%) resulted from filter-protected carotid artery stenting (p<0.019). Total lesion volume per patient did not differ significantly between patients undergoing carotid artery stenting and those undergoing carotid endarterectomy.
Two small randomised trials compared proximal embolic protection (Medtronic MoMa) with distal filters during carotid artery stenting. There were substantial or significant reductions in DW-MRI lesions for the MoMa compared with filter protection.
There were significantly fewer DW-MRI lesions in the MoMa group ipsilateral to the carotid lesion (p<0.0002) but no difference in the DW-MRI lesions in the contralateral hemisphere, implying the embolic penalty associated with catheterisation of the arch/great vessel origins for transfemoral carotid artery stenting. There was also a significant difference in favour of the MoMa system for lesion volume 0