BOLD changes after revascularization in renal artery stenosis patients - preliminary results

Atheromatous renovascular disease (ARVD) is a commonly encountered yet challenging disease to manage. Renal artery stenosis (RAS) is usually focal and is of great clinical importance, not only due to the potential blood flow-limiting effects upon the renal circulation (and subsequent intra-renal ischaemia), but also downstream neuro-hormonal and cytokine release resulting in hypertension, renal impairment and fluid and salt retention. About 90% of RAS lesions are ‘ostial’, occurring unilaterally or bilaterally within 1 cm of the origin of the renal artery and can be treated with renal revascularization. However, renal functional outcomes after revascularization in ARVD are unpredictable with only 30% of patients expected to improve. Prediction of beneficial response remains a great challenge, and is especially important given the small but significant risks of stenting. Blood oxygen level dependent (BOLD) imaging is an MRI technique that does not require contrast administration, and indirectly detects changes in intra-renal oxygenation. R2* values correlate positively with tissue oxygen metabolism and changes in the renal BOLD response could be demonstrated following iv administration of Frusemide in human and pig renal impairment models.