Umbilical artery catheterization in the newborn can cause renal artery stenosis resulting in increased renin and aldosterone. Which finding would you expect?

• A. Pulmonary hypertension
• B. Renal artery stenosis with increased renin and aldosterone
• C. Hypothyroidism
• D. Portal vein thrombosis

Answer: (B)

Renal perfusion is sensed by juxtaglomerular cells, so when the renal artery is injured or narrowed from catheterization, renin release increases. That kick-starts the renin-angiotensin-aldosterone system, raising angiotensin II to constrict vessels and stimulate aldosterone release. Aldosterone then promotes sodium and water reabsorption (expanding blood volume) and potassium loss, leading to hypertension with effects like possible hypokalemia. In a newborn with umbilical artery catheter–related renal artery stenosis, the expected finding is renovascular hypertension with elevated renin and aldosterone levels. The other options don’t fit this mechanism: they don’t involve RAAS activation from reduced renal perfusion.