Can you explain renal artery stenosis?

Will try: Renal artery stenosis is a blockage of the blood flow to the kidney. This may be associated with high blood pressure. It can be diagnosed with a doppler ultrasound of the renal artery in suspected individuals, or some form of a renal angiogram (such as ct or mr angiograms). The stenosis can be dilated sometimes resulting in a decrease in blood pressure levels.

To cause high blood pressure the stenosis must be enough to make the kidney think the BP is too low. The kidney then secretes lots of the hormone renin in an attempt to get the BP back up to what it thinks is normal. This can increase BP to severe levels. When the blockage gets severe the kidney may die.