Successful Renal Artery Stenting in an Infant With Middle Aortic Syndrome: Resolution of Malignant Hypertension and Normalization of Renal Growth
This case report demonstrates that renal artery stenting is a viable and effective treatment for resolving malignant hypertension and restoring renal growth in an infant with middle aortic syndrome when surgical intervention is not feasible.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
High blood pressure in a newborn is a medical emergency, a condition where the heart must push against dangerously high resistance that can damage the delicate organs of the body. In infants, this severe hypertension often stems from a blockage in the tiny pipes that carry blood to the kidneys, known as renal arteries. When these vessels are narrowed, the kidneys perceive a lack of blood flow and signal the body to raise blood pressure even higher, creating a vicious cycle that can lead to heart failure and kidney damage. The most common cause of this blockage in children is a rare condition called middle aortic syndrome, where the main artery running through the abdomen is born unusually narrow or underdeveloped. Treating this in a baby is notoriously difficult because the blood vessels are so small that standard surgical tools cannot fit, and doctors have long worried that placing a permanent metal tube inside a growing child's artery might restrict their natural growth or fail as the child gets bigger.
This story begins with a baby named DL, who arrived at the hospital in the first week of life with blood pressure readings that were dangerously high for a newborn. Ultrasound scans revealed that the right kidney was not receiving enough blood, and the heart was struggling to pump against the pressure. Magnetic resonance imaging confirmed the diagnosis: the main abdominal artery was only three to four millimeters wide, a severe narrowing that extended from the chest down to the hips, causing a critical blockage in the artery feeding the right kidney. For the first year and a half of his life, the medical team managed the condition with powerful medications to lower the blood pressure, as surgery was deemed too risky for a child of his size. However, the medication could not stop the right kidney from shrinking or the blood pressure from remaining stubbornly high, even with three different drugs.
At twenty-two months old, the medical team decided to attempt a procedure that had never been successfully performed on an infant with this specific condition. They threaded a thin wire through the blood vessels to reach the narrowed section of the right renal artery. Using a tiny balloon, they gently widened the blockage before placing a small, drug-releasing stent—a mesh tube designed to hold the vessel open. The stent was expanded to a diameter of 2.6 millimeters, just enough to restore blood flow without damaging the fragile vessel walls. The procedure was successful, and the blood flow to the kidney was immediately restored. In the months that followed, the baby's blood pressure returned to normal, allowing doctors to gradually stop all the blood pressure medications.
The journey did not end there. Four months after the first procedure, follow-up scans showed that the stent had narrowed slightly again, a common concern when treating growing children. Rather than abandoning the approach, the team returned to the catheter lab at twenty-seven months of age. They used a high-pressure balloon to gently stretch the narrowed section of the stent, clearing the blockage once more. This second intervention proved decisive. The blood flow remained steady, and the medications were completely discontinued. Over the next few years, as the child grew, the right kidney, which had previously failed to develop, began to grow at a normal rate, eventually matching the size of the healthy left kidney. By the time the child was five years old, he remained free of high blood pressure without any medication, and both kidneys were growing normally.
This case demonstrates that for infants with severe middle aortic syndrome where surgery is not an option, placing a stent in the renal artery can be a viable path to recovery. While doctors have historically avoided stents in babies due to fears about vessel growth and the small size of the arteries, this outcome suggests that with careful selection and the willingness to perform follow-up procedures if narrowing occurs, the treatment can lead to a complete resolution of hypertension and the recovery of kidney growth. The success of this approach offers a new possibility for other infants facing similar life-threatening blockages, proving that even in the smallest patients, restoring blood flow can allow the body to heal and grow.
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