Transvascular catheter infiltration of the ductus arteriosus with formalin in the newborn lamb: a novel method of establishing and maintaining ductal patency.
OBJECTIVE
This study sought to establish and maintain patency of the ductus arteriosus by a new method of transvascular formalin infiltration of the ductus arteriosus wall.


BACKGROUND
Maintaining patency of the ductus arteriosus postnatally is necessary with many forms of congenital heart disease to ensure survival until definitive surgical repair. A variety of approaches have to date met with variable success.


METHODS
Seven newborn lambs underwent catheterization at 1 to 5 days of age. A functionally closed ductus arteriosus was traversed with a specially designed porous balloon catheter, and the wall was infiltrated with 10% formalin. The ductus was then further dilated with either a 7- or 8-mm diameter balloon.


RESULTS
The ductus arteriosus wall was successfully infiltrated and dilated in all animals. Two lambs were euthanized within 24 h with congestive heart failure from a large ductus, and one lamb was electively euthanized 5 days after transvascular infiltration. Four lambs underwent serial follow-up catheterizations, one of which required repeat balloon dilation 47 days after infiltration. At latest follow-up (mean age [+/- 1 SD] 83 +/- 34 days, range 33 to 108), the pulmonary/systemic flow ratio (2.7 +/- 1.2) was unchanged from immediately after infiltration (1.9 +/- 0.5, p > 0.1). The narrowest diameter of the ductus arteriosus (4.3 +/- 0.4 mm vs. 6.9 +/- 2.6 mm, p > 0.1) and its ratio to that of the adjacent descending aorta (0.5 +/- 0.1 vs 0.4 +/- 0.1, p > 0.1) were also unchanged at latest follow-up. No systemic toxicity was observed. At postmortem study, the ductus was patent, and histologic analysis showed variable intimal and medial destruction, endothelial regeneration, loss of elastic tissue and calcification. Adjacent pulmonary artery and aorta were normal. Based on the small sample size and the observed maximal effect size of 70%, the power of the study is at most 40% to detect significant differences.


CONCLUSIONS
To our knowledge, this is the first time that transvascular formalin infiltration of the ductus arteriosus wall has been applied successfully to maintain ductal patency in the newborn lamb. This method may provide a means of palliation for neonates with certain forms of congenital heart disease.
Weber
H S
HS
Section of Pediatrics (Cardiology), The Pennsylvania State University Childrens Hospital, Hershey, 17033, USA.
Baylen
B G
BG
Banaszak
P
P
Abt
A B
AB
D000818:Animals; D000831:Animals, Newborn; D002404:Catheterization / Q000295:instrumentation* / Q000379:methods; D004373:Ductus Arteriosus / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000502:physiology; D004374:Ductus Arteriosus, Patent / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004867:Equipment Design; D005240:Feasibility Studies; D005557:Formaldehyde / Q000008:administration & dosage* / Q000494:pharmacology; D011859:Radiography; D012756:Sheep; D014654:Vascular Patency / Q000187:drug effects
D005557:Formaldehyde