Author + information
- Djoeke Wolff, MD, PhD⁎ (, )
- Joost P. van Melle, MD, PhD,
- Rolf M.F. Berger, MD, PhD and
- Tjark Ebels, MD, PhD
- ↵⁎Department of Pediatric Cardiology, Beatrix Children's Hospital, University Medical Centre Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
We read with great interest the study by Rogers et al. (1) in which they report their impressive number of 771 patients who underwent Fontan palliation at their institution. We compliment the authors on excellent results. Systematic issues in the study design, however, compel us to comment on their paper.
The Fontan circulation aims at unloading a functionally single ventricle from its previously volume-overloaded state, while treating cyanosis. Most of the patients in Rogers et al. (1) had hypoplastic left heart syndrome (HLHS). Therefore, the authors call the Norwood procedure stage 1, cavopulmonary shunt (CPS) placement is stage 2, and the Fontan completion is stage 3 palliation. In this frame of reference, the authors unwittingly may be extending HLHS terminology to all other single ventricular diagnoses. These different diagnoses call for various different procedures before the Fontan operation either to augment or to reduce the pulmonary circulation, but all resulting in a ventricular volume overload. It is the initiation of the Fontan circulation, which normalizes ventricular preload, that is the crucial step in altering fundamentally the circulation and ventricular preload. In the current era, this initiation is the CPS placement, which is for that reason the first stage of Fontan palliation and is where outcome analyses should start. Fontan completion (inferior caval to pulmonary connection) does not alter ventricular preload.
It used to be customary to institute a Fontan circulation in a single operation, associated with 1 early-stage mortality and no interstage mortality. However, in staged procedures, interstage mortality can be substantial (2). Hence it seems odd, in the Rogers et al. (1) paper, to combine 21 1-stage Fontan procedures with only the second stage of the other patients. Ignoring first-stage and interstage mortality in such an analysis conceals the genuine 2-stage Fontan mortality rates. The relatively low mortality rate in the Rogers et al. paper (1) is influenced strongly by ignoring the mortality associated with CPS placement and the interstage period. Much more could have been concluded from this dataset if patients were entered at the initiation of the Fontan circulation, which is at the CPS placement.
Finally, in response to their excellent early survival after second-stage Fontan procedure, we are curious how their Fontan patients are doing currently. Because the Rogers et al. (1) study deals with 18 years of operations, it would have been interesting to see the long-term attrition in the Fontan circulation.
In conclusion, reporting only the outcome of the second stage of a 2-stage Fontan circulation, as in this paper, sheds no light on the real issues at stake, specifically results including the entire Fontan palliative sequence. Calling CPS placement a second-stage palliation before the real Fontan seems to us an obfuscated paradigm shift, because the Fontan circulation actually has started with the CPS placement.
- American College of Cardiology Foundation
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