DES implantation, reintervention could slow progression of PVS in children

Recent data from an Alabama children’s hospital suggest pediatric patients suffering from pulmonary vein stenosis (PVS) could benefit from repeated catheter intervention.

According to a study published by the Journal of the American College of Cardiology, repeated attempts to slow the progression of PVS with drug-eluting stents (DES) could improve survival rates for children with the disease.

PVS in those under 18 years old is rare, wrote Christopher J. Petit, MD, and colleagues in the study. Even with surgical intervention, the disease is progressive and will likely result in recurrences, progression of stenosis, right heart failure or death. After studying 30 patients ranging in age from 4 months to nearly 10 months, Petit and his colleagues found that DES implantation, reintervention and frequent surveillance catheterization yielded the most favorable results.

All 30 patients underwent intervention at Children’s Healthcare of Atlanta. Sixteen DES, five bare-metal stents (BMS) and nine balloon angioplasties (BA) were administered to the children. Fourteen patients—47 percent of the pool—died between 0.4 and 3.2 months after initial intervention. Reintervention in the remaining 16 patients was associated with better survival rates, with a one-year survival rate of 84 percent. Without reintervention, that rate dropped to 25 percent.

The deaths of all 14 deceased patients were directly related to PVS, the study states, encompassing right heart failure, pulmonary hypertension and respiratory failure.

While DES was the most successful intervention method used in the study, researchers noted no correlation between DES placement and a patient’s survival. One-year vein survival, however, did improve.

PVS has been treated with transcatheter interventions before; the first reports of BA results were recorded in 1982. The largest study of catheter intervention to treat PVS in children reported stent diameter was the biggest indicator of success, but, according to Petit’s work, stent diameter was restricted by the small veins in the infants he was studying.

“There are situations in which patients have small vessels that cannot accommodate a larger stent,” Petit and colleagues wrote. “That was, of course, the case in the majority of our patients. Although we did not evaluate stent diameter as a marker of success, the median stent lumen and balloon diameter among the groups was similar, so the survival rate is primarily showing the difference between the interventions as opposed to size.”

Only one child was fitted with a stent larger than 7 millimeters in diameter, according to the study. The majority of patients were given DES, which have a small maximum luminal diameter of 4 millimeters. Still, though, results of the study showed DES implantation, no matter how small, was more successful than either BA or BMS in terms of vein loss.

Vein loss occurred in more than half of all instances studied. Of the 58 veins that were intervened upon throughout the 11-year study, 34 didn’t survive. Vein survival proved to be higher with the addition of DES implantation and reintervention, though the study’s authors noted that didn’t mean patient survival saw an uptick.

“DES implantation at first catheter intervention appears to be associated with improved vein survival but may not result in improved patient survival,” the authors wrote. “However, reintervention appears to be associated with improved patient survival and vein patency, suggesting that despite mode of treatment, frequent surveillance is important in the care of these patients.”

Atresia was noted in seven of 31 surviving veins and occurred at a median time of 12.1 months after intervention. Researchers noted 15 percent of intervened-upon veins in two deceased patients became atretic before death. One survivor had to undergo pneumonectomy after developing both left upper and lower PV atresia and suffering from severe hemoptysis.

In all, Petit and his colleagues found that while children with PVS are certainly at risk for post-intervention mortality, the addition of DES and reintervention, as well as frequent surveillance, expanded life expectancy in several cases. The researchers were able to follow up with one patient from the study for as long as ten and a half years.

Though 30 patients participated in the study, the researchers did note the patient pool wasn’t substantial.

“Our overall sample size was small, but for this rare disease entity, this is a relatively large cohort that has undergone catheter-based intervention for PVS,” they wrote. “Because of the limited studies available, larger multicenter trials would be beneficial in the further evaluation of catheter-based intervention on PVS in pediatric patients. Additionally, evaluation of newer modalities, including drug-eluting BA, should be further evaluated.”