POST-RADIATION MIDDLE AORTIC SYNDROME: A RARE CULPRIT BEHIND RENOVASCULAR HYPERTENSION IN NEUROBLASTOMA SURVIVORS

Introduction:

Middle aortic syndrome (MAS) is a rare cause of severe hypertension in children. It is characterized by segmental or diffuse narrowing of abdominal and/or distal descending thoracic aorta, involving renal and visceral vasculature. MAS accounts for 0.5-2% of all causes of aortic narrowing. Of these, symptomatic MA after radiation for neuroblastoma is exceedingly rare with only 3 cases reported so far. Given rarity and age of onset, adult nephrologists may have limited experience in managing such patients. Awareness of MAS is hence crucial to manage complications. We present a case of MAS post-radiation therapy for neuroblastoma.

Methods:

Case Description: A 19-year-old F presented in adult nephrology clinic for transition of care. Extensive review of medical records revealed history of stage IV neuroblastoma involving the left kidney at age 21 months. By age 4, she underwent left nephrectomy, tumor resection, and completed radiation therapy. By age 10, she developed recurrent post-prandial abdominal pain and uncontrolled hypertension. MRA abdomen showed segmental abdominal aortic narrowing to 2 mm, starting immediately below the superior mesenteric artery (SMA) and remaining stenotic for about 5 cm inferior to this level up to 3 cm above the aortic bifurcation. Right renal artery arose from the stenotic aortic segment. Clinical picture was consistent with MAS, secondary to radiation exposure. For symptomatic MAS, she underwent double aortic jump graft (aorta-renal artery and aorta-distal aorta) at age 11. Renal function worsened 6 months post-intervention. Graft evaluation showed stenosis of the aorta-renal artery graft requiring balloon angioplasty but soon developed restenosis of right renal artery. Right renal artery was then stented which resulted in improvement in renal function and blood pressure.  She is to remain on clopidogrel and aspirin indefinitely. 

Results:

Discussion: MAS, a rare cause of renovascular hypertension in children was first described in 1963. It is marked by diffuse or segmental narrowing of the abdominal aorta and its branches. Causes can be congenital or acquired. 64% of MAS cases are idiopathic. Genetic forms account for 7-36% with neurofibromatosis type 1 being most common. 84% of cases involve renal artery and bilateral renal artery stenosis occurs in 60% of cases. MAS presents with severe hypertension, post-prandial abdominal pain, abdominal bruit, headache, and discrepancy in blood pressure between extremities. Renovascular hypertension is the most common complication of MAS. Contrast imaging confirms the diagnosis. Left untreated, most patients die by age 40, due to complications of severe hypertension and ischemia. Treatment involves medical therapy and endovascular or surgical intervention. Surgical interventions include aorta-aortic bypass, reconstruction patch graft, or renal auto-transplantation. Endovascular interventions have a high re-intervention rate. 

Conclusions:

MAS is a rare cause of renovascular hypertension. Mortality is high if untreated. Open surgical repair is the gold standard of treatment. MAS requires a high index of suspicion. Pediatric and adult nephrologists need to identify patients at risk to manage and prevent complications.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.