Fate of the Fontan connection: Mechanisms of stenosis and management.
Hagler DJ, Miranda WR, Haggerty BJ, Anderson JH, Johnson JN, Cetta F, Said SM, Taggart NW.
Congenit Heart Dis. 2019 Feb 25. doi: 10.1111/chd.12757. [Epub ahead of print]
Take Home Points:
- Stenosis of the Fontan IVC – PA connection may not be recognized on routine echocardiographic imaging and may require assessment via CT or MRI.
- Percutaneous treatment of Fontan connection stenosis is safe, feasible and may improve patients’ clinical status.
- Fontan patients may benefit for routine invasive assessment after Fontan completion.
Commentary from Dr. Konstantin Averin (Edmonton), catheterization section editor of Pediatric Cardiology Journal Watch: The Fontan procedure is performed with the goal of providing an unobstructed pathway for inferior vena cava (IVC) flow to the pulmonary arteries (PAs). Obstruction of this connection can exacerbate the risks of developing Fontan failure and end-organ injury and should be addressed in a timely fashion. Data on the mechanisms of IVC-PA obstruction and the safety, efficacy and mid-term outcomes of percutaneous intervention are limited. The authors sought to describe a single center experience with intervention on the IVC-PA conduit.
From January 2002 to October 2018 28 patients had conduit obstruction identified (12% of all Fontan catheterizations, 2.5% of all Fontan patients) with 20 meeting inclusion criteria. The median age at catheterization was 17 years, time from Fontan 13 years and weight 59 kg. The most common type of conduit was an extra-cardiac homograft (10/20), followed by extra-cardiac Gore-Tex (6/20), intra-atrial conduit Gore-Tex (1/20), and a lateral tunnel type connection (3/20). More than 50% of patients had evidence of liver cirrhosis. Most patients (12/20) had a single stent implanted with a variety of stents used (covered CP, Palmaz XL/XD, and Intrastent Max LD). The median Fontan diameter increased from 10.5 mm to 18 mm with a decrease in the pressure gradient from 2 mmHg to 0 mmHg.
There were no serious adverse events related to stent implant with 2 patients experiencing small extravasations treated with covered stent implant. A sustained improvement in functional capacity was observed in 11/20 patient’s post-stent with PLE resolution observed in 2/4. No follow up data was presented regarding liver cirrhosis post-stent implant.
The authors conclude that IVC-PA conduit obstruction can be treated safely and effectively with possible improvement in clinical status post-intervention. The authors discuss that there are various mechanisms of stenosis – calcification with luminal narrowing, conduit stretching due to somatic growth, and anastomotic narrowing. Interestingly the authors comment that many of the patients did not have clearly recognized conduit obstruction pre-procedure (6 with no cross sectional imaging and the rest with cross sectional imaging without a clear appreciation of the degree of narrowing). It seems clear that optimizing the IVC to PA connection (targeting a size of 18-20mm) is a critical part of optimizing end-organ health and forestalling the development of long-term Fontan complications.