(140Kb)	Emmel M, Sreeram N, Brockmeier K. Stenting of the aortic arch as an emergency palliation of aortic dissection after cardiac surgery in an infant. Images Paediatr Cardiol 2005,22:8-11

Case report
A 6 month old infant with hypoplastic left heart syndrome, who had previously undergone a Norwood procedure, was admitted for stage 2 palliation with a superior vena cava to pulmonary artery shunt. Aortic cannulation was performed using a 3.0 mm cannula, for induction of cardiopulmonary bypass. The cannula was inserted into the native tissue of the reconstructed arch. After initial cannula insertion, no bleedback was noted, and the cannula had to be inserted for a second time. Thereafter, the surgical procedure was routinely performed. Weaning off bypass was uneventful, and the sternum was closed in a normal fashion. Ten minutes after chest closure there was no blood pressure measurable in the femoral artery, while the pulses were normal in the upper limb. At echocardiography there was no detectable flow in the descending aorta, but further details could not be discerned.
 

Emergency cardiac catheterization, performed via the femoral vein and artery demonstrated a dissection of the aortic arch, starting in the transverse arch (Fig. 1). Because of the critical clinical state of the patient it was decided to undertake emergency palliation by percutaneous stent implantation. Via an 0.035"guidewire in the aorta, inserted from the right femoral vein, two premounted Palmaz (8mm diameter each) were inserted in series, to cover the dissection flap.
 

This resulted in good angiographic patency of the arch, with normal lower limb blood pressures again being recordable. Despite restoration of appropriate arch patency and adequate urine output, the patient died 24 hours later with multi-organ failure. A post mortem study was not performed.
 

 

Discussion
Aortic dissection in infancy is rare,^1,2 and when it occurs, the aetiology is either trauma or iatrogenic. There is no recommended standard treatment. In our patient, reopening of the sternum and recommencement of cardiopulmonary bypass was not considered to be an appropriate option, due to the critical clinical state of the patient. Stent implantation resulted in excellent immediate palliation. The mechanism of dissection was possibly related to initial cannulation, which resulted in a tear of the native aortic tissue and intramural bleeding.^1,3,4 Although the patient died 24 hours later, this was not a direct result of residual aortic obstruction but from preceding events.
 

References

1. Walther T, Kiefer H, Dahnert I, Kostelka M. Successful treatment for intraoperative evolving acute aortic dissection in a neonate. Ann Thorac Surg 2003;76:1286-1287.
2. Zalzstein E, Hamilton R, Zucker N, Diamant S, Wenn G. Aortic dissection in children and young adults: diagnosis, patient at risk, and outcomes. Cardiol young 2003;13:341-344.
3. Nagy Z, Heinemann MK, Schmid E, Ziemer G. Successful repair of intraoperative type-A dissection in an infant. Europ J Cardiothorac Surg 2002;22:636-637.
4. Paul JJ, Desai H, Baumgart S, Wolfson P, Russo P Tighe DA: Aortic dissection in a neonate associated with arterial cannulation for extracorporeal life support. ASAIO J. 1997;43:92-94.