The elusive and ungrateful lymphatic circulation may be a key determinant of Fontan failure

Transcatheter Thoracic Duct Decompression for Multicompartment Lymphatic Failure After Fontan Palliation

BACKGROUND

Lymphatic embolization therapy has proven effective for Fontan failure from plastic bronchitis or protein-losing enteropathy but not when multiple lymphatic compartments are involved; furthermore, embolization does not alter the underlying pathophysiology of lymphatic dysfunction. A technique for transcatheter thoracic duct decompression (TDD), rerouting the thoracic duct to the pulmonary venous atrium to treat multicompartment lymphatic failure is described and early outcomes presented.

METHODS

Initially covered stents were used to channel the innominate vein flow inside of the cavopulmonary pathway into the pulmonary venous atrium. A modified approach was developed where covered stents redirected innominate vein directly to the left atrium via an extravascular course. Baseline and follow-up data on all patients undergoing TDD were reviewed.

RESULTS

Twelve patients underwent TDD between March 2018 and February 2021 at a median age of 12 (range: 2-22) years. Lymphatic failure occurred in median of 3 compartments per patient (protein-losing enteropathy, ascites, pleural effusions, plastic bronchitis); 10 patients had lymphatic embolizations before TDD. TDD method was intra-Fontan tunnel in 4, direct approach in 7, and other in 1. There were no major procedural complications; 6 patients underwent subsequent procedures, most commonly to treat endoleaks. Lymphatic failure resolved in 6 patients, improved in 2, and was unchanged in 4 at 6 (range: 1-20) months follow-up. One patient died after TDD from Fontan failure.

CONCLUSIONS

TDD is a promising new treatment for the failing Fontan physiology from multicompartment lymphatic failure. Additional work is needed to refine the technique and define optimal candidates.

Functional lymphatic reserve capacity is depressed in patients with a Fontan circulation

Background

Lymphatic abnormalities play a role in effusions in individuals with a Fontan circulation. Recent results using near‐infrared fluorescence imaging disclosed an increased contraction frequency of lymphatic vessels in Fontan patients compared to healthy controls. It is proposed that the elevated lymphatic pumping seen in the Fontan patients is necessary to maintain habitual interstitial fluid balance. Hyperthermia has previously been used as a tool for lymphatic stress test. By increasing fluid filtration in the capillary bed, the lymphatic workload and contraction frequency are increased accordingly. Using near‐infrared fluorescence imaging, the lymphatic functional reserve capacity in Fontan patients were explored with a lymphatic stress test.

Methods

Fontan patients (n = 33) were compared to a group of 15 healthy individuals of equal age, weight, and gender. The function of the superficial lymphatic vessels in the lower leg during rest and after inducing hyperthermia was investigated, using near‐infrared fluorescence imaging.

Results

Baseline values in the Fontan patients showed a 57% higher contraction frequency compared to the healthy controls (0.4 ± 0.3 min⁻¹ vs. 0.3 ± 0.2 min⁻¹, p = 0.0445). After inducing stress on the lymphatic vessels with hyperthermia the ability to increase contraction frequency was decreased in the Fontan patients compared to the controls (0.6 ± 0.5 min⁻¹ vs. 1.2 ± 0.8 min⁻¹, p = 0.0102).

Conclusions

Fontan patients had a higher lymphatic contraction frequency during normal circumstances. In the Fontan patients, the hyperthermia response is dampened indicating that the functional lymphatic reserve capacity is depressed. This diminished reserve capacity could be part of the explanation as to why some Fontan patients develop late‐onset lymphatic complications.

Lymphatic Decompression Concomitant With Fontan/Kreutzer Procedure: Early Experience

OBJECTIVE

To present a strategy for identifying patients at risk of lymphatic failure in the setting of planned Fontan/Kreutzer completion, allowing a tailored surgical approach.

METHODS

Since January 2017, clinical evaluation before performance of the Fontan/Kreutzer procedure included T2-weighted magnetic resonance imaging (MRI) lymphangiography. Thoracic lymphatic abnormalities were categorized using a scale of I to IV according to progression of severity. Patients with severe lymphatic abnormalities (types III and IV) underwent Fontan/Kreutzer with lymphatic decompression via connection of the left jugular-subclavian junction containing the thoracic duct to the systemic atrium (group A).

RESULTS

Thirteen patients were enrolled. Magnetic resonance imaging showed type I abnormalities in four cases (30.7%), II in four (30.7%), III in two (15.3%), and IV in three (23.3%). Patients in types III and IV underwent a Fontan/Kreutzer with lymphatic decompression (group A, n = 5), while patients in types I and II underwent a fenestrated extracardiac Fontan/Kreutzer procedure without lymphatic decompression (group B, n = 8). Preoperatively, there were no differences in age, weight, ventricular dominance (right vs left), superior vena cava pressure, incidence of chylothorax after previous superior cavopulmonary anastomosis (Glenn), or need for concomitant procedures at Fontan/Kreutzer completion. There were no differences in procedural times between the groups, nor were there differences in mortalities and Fontan/Kreutzer takedowns. There were no statistically significant differences in early and late morbidity between the two groups with the exception of total volume of effusions output postoperatively. At median follow-up of 18 months (range, 4-28 months), all patients in group A are in New York Heart Association class 1 with no differences between groups in arterial oxygen saturation.

CONCLUSIONS

Lymphatic decompression during Fontan/Kreutzer procedure was successfully performed in patients identified by MRI as predisposed to lymphatic failure. A larger cohort of patients and longer follow-up are required to determine the efficacy of this approach in preventing early- and long-term Fontan/Kreutzer failure.

Prevalence and Cause of Early Fontan Complications: Does the Lymphatic Circulation Play a Role?

Background

Recent studies suggest that lymphatic congestion plays a role in development of late Fontan complications, such as protein‐losing enteropathy. However, the role of the lymphatic circulation in early post‐Fontan outcomes is not well defined.

Methods and Results

This was a retrospective, single‐center study of patients undergoing first‐time Fontan completion from 2012 to 2017. The primary outcome was early Fontan complication ≤6 months after surgery, a composite of death, Fontan takedown, extracorporeal membrane oxygenation, chest tube drainage >14 days, cardiac catheterization, readmission, or transplant. Complication causes were assigned to 1 of 4 groups: (1) Fontan circuit obstruction, (2) ventricular dysfunction or atrioventricular valve regurgitation, (3) persistent pleural effusions in the absence of Fontan obstruction or ventricular dysfunction, and (4) chylothorax or plastic bronchitis. T2‐weighted magnetic resonance imaging sequences were used to assess for lymphatic perfusion abnormality. The cohort consisted of 238 patients. Fifty‐eight (24%) developed early complications: 20 of 58 (34.5%) in group 1, 8 of 58 (14%) in group 2, 18 of 58 (31%) in group 3, and 12 of 58 (20%) in group 4. Preoperative T2 imaging was available for 126 (53%) patients. Patients with high‐grade lymphatic abnormalities had 6 times greater odds of developing early complications (P=0.001).

Conclusions

There is substantial morbidity in the early post‐Fontan period. Half of those who developed early complications had lymphatic failure or persistent effusions unrelated to structural or functional abnormalities. Preoperative T2 imaging demonstrated that patients with higher‐grade lymphatic perfusion abnormalities were significantly more likely to develop early complications. This has implications for risk stratification and optimization of patients before Fontan palliation.