EP136: Narrowed Artery to the Kidney

Welcome to my podcast. I am Doctor Warrick Bishop, and I want to help you to live as well as possible for as long as possible. I’m a practising cardiologist, best-selling author, keynote speaker, and the creator of The Healthy Heart Network. I have over 20 years as a specialist cardiologist and a private practice of over 10,000 patients. Podcast Summary Introduction Dr. Warrick Bishop is a practicing cardiologist and author dedicated to educating patients about heart health through his podcast and Healthy Heart Network. In this episode, Dr. Bishop explores renal artery stenosis—a narrowing of the arteries supplying the kidneys—and explains why this condition is an interesting and important cause of elevated blood pressure that clinicians need to recognize. Key Takeaways: The kidneys receive approximately 25% of the blood pumped by the heart at rest and depend heavily on adequate blood flow to filter waste products, maintain fluid balance, and remove toxins from the body. Renal artery stenosis occurs when an artery supplying a kidney becomes narrowed, reducing blood flow to that organ and triggering a compensatory response. When a kidney senses reduced blood flow, it releases renin, which initiates a hormonal cascade converting angiotensin 1 to angiotensin 2, a potent hormone that constricts blood vessels throughout the body and raises blood pressure. Renal artery stenosis is a significant cause of difficult-to-control high blood pressure, particularly in young patients with severely elevated readings. Fibromuscular dysplasia, a condition characterized by fibrosis and narrowing of arterial muscle tissue, commonly causes renal artery stenosis in middle-aged women. Atherosclerotic plaque buildup in renal arteries is a frequent cause of renal artery stenosis in elderly patients. In the rare but serious case of bilateral renal artery stenosis (narrowing in both kidneys), ACE inhibitors and angiotensin II receptor blockers can cause a sudden, significant decline in kidney function by blocking the compensatory renin-angiotensin system. Patients with difficult-to-treat high blood pressure who experience a precipitous drop in kidney function after starting ACE inhibitors or AT2 blockers should be evaluated for bilateral renal artery stenosis.