Ghosh RM, Griffis HM, Glatz AC, Rome JJ, Smith CL, Gillespie MJ, Whitehead KK, O’Byrne ML, Biko DM, Ravishankar C, Dewitt AG, Dori Y.
J Am Heart Assoc. 2020 Apr 7;9(7):e015318. doi: 10.1161/JAHA.119.015318. Epub 2020 Mar 30.
PMID: 32223393 Free Article
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Take Home Points:
- Nearly a third of patients developed complications in the first 6 months post Fontan completion.
- This was mainly driven by prolonged pleural effusions, readmission or unplanned cardiac catheterization.
- Prolonged cross-clamp time and prolonged bypass time emerged as risk factors for early Fontan morbidity.
- The presence and severity of AV valve regurgitation did not influence early outcomes.
- The presence of a type 3 or type 4 lymphatic drainage pattern on MRI (T2 -weighted) was associated with higher early failure rates (Odds ratio 6.28).
Commentary from Dr. Blanche Cupido (Cape Town, South Africa), section editor of ACHD Journal Watch: Recent studies implicated the role of lymphatic congestion in the pathogenesis of both protein-losing enteropathy and plastic bronchitis in patients with the Fontan circulation resulting in late Fontan failure. The role of lymphatic drainage in the development of early Fontan complications is not well described. This is a single center retrospective study at a tertiary paediatric center in the US, describing the prevalence and cause of early post-Fontan morbidity.
All patients who underwent a Fontan operation from June 2012 to July 2017 were included. Those presenting for a Fontan take-down, those for Fontan revision or those with a Kawashima operation, were excluded. Lymphatic patterns were characterized using T2-weighted images. Patterns included 4 types:
- Type 1: Little or no abnormalities of the thoracic duct
- Type 2: Enhancement of the supraclavicular area and dilatation and/or tortuosity of the thoracic duct
- Type 3: Enhancement of mediastinal and supraclavicular area
- Type 4: enhancement extending from the mediastinum into the lung parenchyma
The primary outcome was a composite of early Fontan complications (within 6 months of surgery) including death, Fontan take-down, ECMO, chest drain >14 days, cardiac catheterization, re-admission, heart transplant listing. Fontan failure is characterized into 4 groups: structural failure, pump failure, pleural (non-chylous) effusions despite lack of pump or structural failure, and lastly lymphatic failure – usually presenting with chylothorax or plastic bronchitis.
Two hundred and thirty-eight patients were included in the study; 58 developed early Fontan complications (25.7%) – only 2 deaths occurred. Mean age at surgery was 3.4±1.7 years. An extra-cardiac fenestrated Fontan was present in 81% of the cohort.
The presence of a systemic RV (81% vs 67%, p0.047), a longer bypass time (median time 69.5 vs 64 minutes, p=0.025) and a longer cross-clamp time (median time 29 vs 25 min, p=0.002) was associated with a higher rate of early post-Fontan complications. The presence and severity of atrio-ventricular valve regurgitation did not have an effect on early outcomes.
Fontan failure was attributed to structural failure in 20 patients (35%), and to pump failure in 8 patients (14%). The presence of severe Fontan complications was only 4%. Fifteen patients (21.5%) had prolonged effusions and 15 patients (21.5%) had lymphatic failure as evidenced by plastic bronchitis or chylous effusions.
One hundred and ninety-five patients (82%) had pre-Fontan MRI’s. The systemic-pulmonary arterial collateral (APC) burden was quantified and expressed as a percentage of the total aortic flow. Of the 51 patients with a >35% APC burden, 43 had collateral embolization prior to Fontan completion. Only 126 patients had the correct T2 weighted sequences to establish lymphatic flow patterns: 39 had type 1, 41 had type 2, 35 had type 3. Only 7 had type 4 – thus rather rare.
Forty- three percent of those with type 3 pattern and all of those with the type 4 pattern developed early complications. Type 3 and type 4 patterns were combined and regarded as high-grade lymphatic abnormalities.
Type 3 and 4 combined subtended an odds-ratio of 6.05 (95% CI 2.10-17.46, p=0.001) for developing complications compared to those with a type 1 pattern. When controlling for a morphological RV, bypass and cross-clamp time, the odds ratio was 6.28 (95% CI 2.13 – 18.5, p=0.001) for developing early Fontan complications.
