Pediatric Cardiology

Comparison of Patent Ductus Arteriosus Stent and Blalock-Taussig Shunt as Palliation for Neonates with Sole Source Ductal-Dependent Pulmonary Blood Flow: Results from the Congenital Catheterization Research Collaborative. Bauser-Heaton H, Qureshi AM, Goldstein BH, Glatz AC, Ligon RA, Gartenberg A, Aggarwal V, Shashidharan S, McCracken CE, Kelleman MS, Petit CJ. Pediatr Cardiol. 2022 Jan;43(1):121-131. doi: 10.1007/s00246-021-02699-7. PMID: 34524483   Commentary from Dr. Manoj Gupta (New York City, NY, USA), chief section editor of Pediatric & Fetal Cardiology Journal Watch.   Take Home Points: Patent ductus arteriosus (PDA) stenting is an accepted method for securing pulmonary blood flow in cyanotic neonates. In neonates with pulmonary atresia and single source ductal-dependent pulmonary blood flow (SSPBF), PDA stenting remains controversial. Thirty-five patients with PDA stents and 156 patients with BTS were included. Interstage reintervention rates were higher in the PDA stent cohort (48.6% vs. 15.4%, p<0.001) This study supports the use of PDA stenting as a form of palliation in neonates with SSPBF (single source ductal-dependent pulmonary blood flow).   Introduction: In the most recent American Heart Association Scientific Statement, PDA stenting in the setting of SSPBF received a Class IIb recommendation of “might be reasonable. The authors hypothesized that, SSPBF as a barrier to PDA stenting may be overcome as centers and operators gain experience with the technical approach to stenting and supporting labile neonates with a single, prostaglandin-sensitive source of pulmonary blood flow. Children’s Hospital of Atlanta, Cincinnati Children’s Hospital Medical Center, Texas Children’s Hospital, and Children’s Hospital of Philadelphia cohorts were analyzed during this study from Jan 2008 to December 2015.   Methods Patients included in the cohort had a congenital cardiac diagnosis consistent with ductal dependent SSPBF and underwent BTS or PDA stent palliation in the neonatal period (≤30 days of age). Procedural outcomes, including complications, length of stay (LOS), need for post-procedural inotropic support, mechanical ventilation, and diuretic use post-palliation, were collected. Branch pulmonary artery diameter (measured at the hilum) was reviewed at the time of initial palliation as well as immediately prior to definitive surgical repair or next palliative stage (e.g., bidirectional Glenn anastomosis) using available imaging. “Reintervention” was defined as those exclusively on the PDA stent or the BTS if the reintervention occurred prior to surgical repair or planned palliation and was focused solely on the shunt or stent itself and did not involve the branch pulmonary arteries or other areas.   Results During the study period, 191 neonates with SSPBF underwent either PDA stent (n=35) or BTS (n=156). The baseline characteristics of the two cohorts were equivalent with a few notable exceptions. The PDA stent cohort was composed of more neonates with pulmonary atresia and intact ventricular septum (PA-IVS) compared with the BTS cohort (49% vs 28%, p=0.022). Single ventricle heart disease, presence of genetic syndrome, and pre-intervention clinical status were similar between the cohorts. Following initial palliation, ICU LOS was not different between the two cohorts (median ICU LOS 10 days for PDA and 7 days for BTS, p = 0.341). Hospital LOS was also similar between groups (p=0.178). The PDA stent cohort was less likely to receive inotropic support (p<0.01) or to be discharged on diuretics (OR 0.45, 95% CI [0.21–0.97], p = 0.042).     Complications and Reinterventions Procedural complications occurred in both groups at similar rates. However, major procedural complications occurred in 9 infants undergoing BTS and in no patients undergoing PDA stenting (p= 0.146). Adjusted analysis indicated no difference in overall rates of complications between PDA stent and BTS cohorts. Reintervention was more common in the PDA stent cohort when comparing any reintervention or reintervention on the shunt or stent itself Reintervention on the PDA stent itself was more common than on the BTS (adjusted p < 0.001). Similarly, rate of any reintervention following initial palliation was higher in the PDA stent cohort (adjusted p < 0.001). When considering timing of reintervention, it appears that the greatest period of risk for reintervention was >1 month from initial palliation.   Pulmonary Artery Growth & Interventions The pulmonary arteries were somewhat smaller pre-intervention in the PDA stent cohort (unadjusted median Nakata index 109 mm2 /m2 , 25th–75th 70–149) compared with the BTS cohort (unadjusted Nakata index 128 mm2 /m2 , 25th–75th 96–157, adjusted p=0.071). The increase in Nakata index from palliation to definitive repair or bidirectional Glenn was not statistically significant between cohorts. Interestingly, the branch pulmonary arteries were more asymmetric at the time of initial palliation in the PDA stent cohort (PA symmetry index 0.81, 25th–75th 0.72–0.92) compared with the BTS cohort (PA symmetry index 0.87, 25th–75th 0.79–0.95, adjusted p=0.016). At time of surgical repair or palliation, pulmonary artery symmetry was similar, with a symmetry index of 0.88 (25th–75th 0.77–0.97) in the PDA stent cohort compared with 0.82 (25th–75th 0.71–0.92), p= 0.857). At time of definitive surgical repair or staged surgical palliation, surgical pulmonary artery plasty was common in both cohorts, with 60.0% of the PDA stent cohort and 42.5% of the BTS cohort undergoing pulmonary artery plasty.     Discussion Although overall complication rates were equivalent, complications were more severe in the BTS group. The group palliated with PDA stenting underwent a higher rate of reinterventions compared with the surgical BTS group. Importantly, the two palliative cohorts had similar measures of PA growth, symmetry, and size at time of definitive repair/palliation, suggesting that candidacy for surgical repair or single ventricle palliation was preserved regardless of palliative modality. The current study does not include an equal balance of BTS and PDA stent patients and does not include data on any unsuccessful PDA stent “attempts.” The late reinterventions noted in the PDA stent cohort likely relate to the known issues of neointimal proliferation which commonly occurs in infants following PDA stenting and appears to be more common in infants with highly tortuous Type III PDAs.   Conclusion While PDA anatomy and the SSPBF physiology pose challenges, PDA stenting appears to offer equivalent clinical outcomes and durability as an initial palliative strategy compared with surgical BTS.