Fontan Circuit Research Articles

FibroScan as a surveillance marker post-cavopulmonary anastomosis for single-ventricle physiology.

Single-ventricle physiology encompasses a group of congenital cardiac malformations with only one functional ventricle. The Fontan procedure is the final palliation of this pathway and has its complications. One of these is Fontan-associated liver disease (FALD). It is known that all patients with Fontan will have FALD, due to the physiology of the Fontan circuit, and only the severity will vary. The pathophysiology of hepatic damage in FALD is unique and not easily detectable by routine non-invasive investigations. Therefore, this study is aimed to identify if FibroScan can be used as a surveillance marker to detect and assess the progression of FALD. Patients who attended the Cardiothoracic and Vascular Surgery Outpatient Department (OPD) for follow-up post-cavopulmonary anastomosis (bidirectional Glenn and Fontan) were enrolled in this study. They underwent routine examinations and tests, and in addition a FibroScan was performed. FibroScan showed that the liver stiffness measurement (LSM) was increased in all patients who had undergone Fontan and a couple of patients who had undergone bidirectional (BD) Glenn. The LSM was 12.29 (± 3.59) kPa in patients post-Fontan and 6.64 (± 4.24) kPa in patients post-BD Glenn. This raised LSM was not associated with a parallel rise in liver enzymes or other laboratory markers associated with liver function. This emphasizes the suitability of FibroScan as an early and non-invasive surveillance tool for monitoring the progression of hepatic venous congestion and FALD. We have found that LSM via FibroScan can effectively be a surveillance or screening test for FALD. Serial FibroScans can be used to monitor the progress of liver disease. Raised LSM may also have a role in predicting the morbidity for completion of Fontan post-BD Glenn operation. Large-scale studies are needed to validate our findings.

Are dynamic measurements of central venous pressure in Fontan circulation during exercise or volume loading superior to resting measurements?

The main objective measure to assess the health of the Fontan circulation is the pressure measurement of the superior vena cava or pulmonary arteries. We reviewed the literature for benefits of measuring resting pressure in the Fontan circuit and explored whether dynamic measurement by volume loading or exercise has the potential to refine this diagnostic tool. PubMed was searched for articles showing a relationship between resting post-operative central venous pressure or pulmonary artery pressure and Fontan failure. Relationships between post-operative central venous pressure or pulmonary artery pressure and volume loading changes, such as during exercise or volume loading during cardiac catheterization, were also queried. A total of 44 articles mentioned relationships between resting central venous pressure or pulmonary artery pressure and Fontan failure. Only 26 included an analysis between the variables and only seven of those articles found pressure to be predictive of Fontan failure. Ten articles examined the relationship between exercise or volume loading and outcomes and demonstrated a large individual variation of pressures under these dynamic conditions. Based on current literature, there is not a lot of strong evidence to show that elevated resting central venous pressure or pulmonary artery pressure is predictive of Fontan failure. Some individuals experience dramatic increases in central venous pressure or pulmonary artery pressure under increased loading conditions with exercise or bolus fluid infusion, while others experience increases closer to that of a healthy control population. Further studies are needed to examine whether more dynamic and continuous monitoring of systemic venous pressures might better predict outcomes in patients with Fontan circulation.

A surveillance for advanced liver disease and characterization of hyperechogenic lesions after Fontan surgery in a prospective cohort of cases with congenital univentricular heart

Abstract Background The congenital univentricular heart (UH) is a rare disease corrected with the palliative Fontan’s intervention, that restores the survival of most child and young patients up to adultwood. Unlikely, these patients develop a series of complications, among all, the Fontan associated liver disease (FALD), that causes the occurrence of liver cirrhosis and hepatocellular carcinoma (HCC), that negatively impacts the life expectancy in the majority of cases. Purpose Our primary aim was to identify the presence of severe FALD in our patients by liver fibrosis and portal hypertension scores (FORNS, liver and spleen-platelet score or LSPS and SSPS), and by liver (LS) and spleen (SS) stiffness measurement in relation to time since Fontan, and secondarly to characterize all the abdominal-US hyperechogenic lesions (US-HL) according to the LI-RADS (LR) CT/MRI categories. Method One-hundred-46 outpatients (83 m/63 f, aged 25,2±11.0 yrs) born with UH corrected with Fontan circuit have been recruited prospectively from 2019 to 2023 (FUmean 24.5±15.1 mos). Each patient underwent a complete clinical history and instrumental examination, by imaging obtained with US, CT and MRI, a specific lab-test profile, and the LS and SS evaluation by transient elastography (VCTE, Fibroscan). ROC curves were built to select the scores cut-off proved to be the most accurate to diagnose and grade FALD. Based on the presence of US-HL found in 43 cases (29,5%), we grouped: 23 cases with LR-1 or 2 (benign), 15 with LR-3 (suspect) and 5 with LR-4 or 5 (malign). Results Features for definition of failing-Fontan appeared in 17.5%, 47.5% and 80% of cases with <15; 15-25 or >25yrs since Fontan surgery, respectively (p<0.01). All the scores used (FORNS with cut-off ≥4, LSPS ≥1.4, SSPS ≥2.3, LS ≥20.2 and SS ≥30.7) showed high sensitivity and specificity, improving FALD diagnostic accuracy and staging (all p<0.001). Moreover by identification of selective criteria related to advanced liver disease and portal hypertension, we applied a novel risk-score for failing-Fontan, that predicted a low-moderate risk profile (HR 0.30;CI 0.18-0.52) in 72 patients and a high risk profile (HR 3,29,CI 1.93-5.60) in 74 (51%). During FU, 13 patients (8.9%) died, 5 received OHT (3.4%) and 5 had HCC occurrence (3.4%). Finally, cases with US-HL stratified by classes LR-3-4-5 (20 cases, 46.5%) appeared significantly associated with a more advanced FALD (16/4, 75% vs. 68/58, 46%; p=0,004) and a longer time since Fontan (26.3±9.4 vs. 19.8±10.8; p=0,025). Conclusion The novel risk score proposed may help to predict the development of cirrhosis in high risk patients and focussed on the need for surveillance by imaging methods to characterized the US-HL, that appeared at risk of malignity (nodule size >20mm and/or presence of wash-out into portal-hepatocellular phase or into LR ≥3 classes).

Hemi-Fontan and bidirectional Glenn operations result in flow-mediated viscous energy loss at the time of stage II palliation

BackgroundSuperior cavopulmonary connection (SCPC) for stage II palliation of hypoplastic left heart syndrome (HLHS) is achieved most frequently by either a bidirectional Glenn (BDG) or hemi-Fontan (HF) operation. The comparison of flow hemodynamic efficiency at the region of surgical reconstruction and in proximal pulmonary arteries has been evaluated primarily using computational modeling techniques with conflicting reports. The purpose of this descriptive study was to compare flow hemodynamics following stage II (BDG vs HF) using 4-dimensional flow magnetic resonance imaging (4D-Flow MRI) with particular focus on flow-mediated viscous energy loss (EL’) under matched hemodynamic conditions. MethodsPatients with hypoplastic left heart syndrome (HLHS) who underwent either HF or BDG as part of stage II palliation underwent pre-Fontan 4D-Flow MRI. Patients were matched by the pulmonary vascular resistance index, net superior vena cava (SVC) flow, right pulmonary artery (RPA) and left pulmonary artery (LPA) size, and age. Maximum EL’ throughout the cardiac cycle was calculated along the SVC-RPA and SVC-LPA tracts. ResultsEight patients who underwent HF as part of their stage II single ventricle palliation were matched with 8 patients who underwent BDG. There were no differences between the 2 groups in median volumetric indices, including end-diastolic volume (P = .278) and end-systolic volume (P = .213). Moreover, no differences were observed in ejection fraction (P = .091) and cardiac index (P = .324). There also were no differences in peak EL’ measured along the SVC-RPA tract (median, 0.05 mW for HF vs 0.04 mW for BDG; P = .365) or along the SVC-LPA tract (median, 0.05 mW vs 0.04 mW; P = .741). ConclusionsThe second stage of surgical palliation of HLHS using either HF or BDG results in similar flow-mediated viscous energy loss throughout the SCPC junction. 4D-Flow MRI and computational methods should be applied together to investigate flow hemodynamic patterns throughout the Fontan palliation and overall efficiency of the Fontan circuit.

Respiratory Muscle Function and Exercise Performance in Adult Patients with Fontan Circulation.

At rest, a good Fontan circulation can provide a normal cardiac output (CO). However, as a consequence of its unique hemodynamic nature, the limitations of the Fontan circuit are exposed during exercise. We aimed to provide a comprehensive assessment of the pathophysiology of exercise in adult Fontan patients (FPs) and identify factors limiting their functional capacity (FC). In a single-center study conducted in 37 FPs aged ≥16 years and 19 healthy-controls (HCs) who underwent CPET on a cycle ergometer in February and March 2022, the mean peakVO2 was 21 ± 5.4 mL/kg/min, which was 55% of the predicted value. Morphologically, the left single ventricle showed a higher peakVO2% predicted value (57.4 ± 14.4% vs. 43.4 ± 8.1%, p = 0.045). The factors associated with low peakVO2 values were an early flattened or descending O2 pulse at maximal exertion (52 ± 14% vs. 62 ± 12.5, p = 0.04 and 47.6 ± 9% vs. 60 ± 14, p = 0.018, respectively) and chronotropic insufficiency (53 ± 12% vs. 69.8 ± 20%, p = 0.008). The OUES was found to be a useful parameter to assess the FC in FPs in maximal and submaximal exercise testing. A strong positive correlation was observed between the %OUES and peakVO2%predicted (r = 0.726, p > 0.001). The lung function was impaired in the FPs, mostly with a mild restrictive pattern (56.8%). The FPs showed lower inspiratory muscle strength compared to the HCs but it was not statistically associated with either the peakVO2 or VE/VCO2 slope. Regular intense physical activity improves one's FC. Although FPs have inspiratory muscle weakness, its impact on their FC is unclear. The peakVO2% predicted grew progressively higher as the level of physical activity increased (low level 49.5 ± 14%, moderate level 55 ± 12%, intense level 69 ± 20%).

Safety and efficacy of transcatheter closure of Fontan fenestration with atrial septal occluder

Objective: To assess the safety and efficacy of transcatheter fenestration closure following Fontan procedure with an atrial septal occluder. Methods: This is a retrospective study. The study sample consists of all consecutive patients who underwent closure of a fenestrated Fontan baffle at Shanghai Children's Medical Center Affiliated to Shanghai Jiaotong University School of Medicine between June 2002 and December 2019. The indications of Fontan fenestration closure included that normal ventricular function, targeted drugs for pulmonary hypertension and positive inotropic drugs were not required prior the procedure; and the Fontan circuit pressure was less than 16 mmHg (1 mmHg=0.133 kPa) and no more than a 2 mmHg increase during test occlusion of the fenestration. Electrocardiogram and echocardiography were reviewed at 24 hours, 1, 3, 6 months and annually thereafter post procedure. Follow-up information including clinical events and complications related to Fontan procedure was recorded. Results: A total of 11 patients, including 6 males and 5 females, aged (8.9±3.7) years old were included. The types of Fontan were extracardiac conduits (7 cases) and intra-atrial duct (4 cases). The interval between percutaneous fenestration closure and the Fontan procedure was (5.1±2.9) years. One patient reported recurrent headache after Fontan procedure. Successful fenestration occlusion with atrial septal occluder was achieved in all patients. Compared with prior closure, Fontan circuit pressure ((12.72±1.90) mmHg vs. (12.36±1.63) mmHg, P<0.05), and aortic oxygen saturation ((95.11±3.11)% vs. (86.35±7.26)%, P<0.01) were increased. There were no procedural complications. At a median follow-up of (3.8±1.2) years, there was no residual leak and evidence of stenosis within the Fontan circuit in all patient. No complication was observed during follow-up. One patient with preoperative headache did not have recurrent headache after closure. Conclusions: If the Fontan pressure is acceptable by test occlusion during the catheterization procedure, Fontan fenestration could be occluded with the atrial septum defect device. It is a safe and effective procedure, and could be used for occlusion of Fontan fenestration with varying sizes and morphologies.

Successful balloon dilatation of an infolded polytetrafluoroethylene graft: An unusual cause of early Fontan failure.

Despite optimal medical management, an 8-year-old boy had persistent pleural drainage following total cavopulmonary connection. Detailed evaluation, including computed tomography angiography, confirmed obstruction at the lower end of the circuit due to infolding of the polytetrafluoroethylene graft. Balloon dilation of the obstruction resulted in prompt resolution of pleural effusion with sustained relief at 1-year follow-up. The case demonstrates the importance of careful assessment in the diagnosis and successful nonsurgical management of an unusual cause of obstruction in the Fontan circuit.

Abstract 12163: Liver Disease in Right Heart Failure: Not Just Fontan Associated

Introduction: Hepatic fibrosis, cirrhosis, and hepatocellular carcinoma caused by the Fontan circulation, known as Fontan Associated Liver Disease (FALD), are due to low cardiac output and high venous pressure within the Fontan circuit. Hypothesis: We hypothesized that patients with congenital heart disease causing right heart dysfunction would have liver findings similar to FALD. Methods: We identified patients with the Fontan circulation or congenital heart disease associated with moderately depressed or dilated RV on echo or MRI, and/or increased right atrial pressure on cardiac cath. We defined hepatic congestion as increased kPA on Fibroscan, liver or IVC abnormalities on US, increased kPA or liver abnormalities on MRI elastography, and/or sinusoidal congestion on liver biopsy. The incidence of hepatic congestion was compared by chi squared analysis. Results: A total of 33 patients were identified for this study, 23 Fontan and 10 non-Fontan. Hepatic congestion was found in 25 patients (76%). Hepatic congestion was most often diagnosed by US in both Fontan (82.6%) and non-Fontan patients (40%). The most common findings on liver biopsy, including one non-Fontan Ebstein, were sinusoidal dilation, portal fibrosis, and perisinusoidal fibrosis. The incidence of hepatic congestion in Fontan was no different from non-Fontan however power was limited. Conclusions: Hepatic congestion was found in 83% of Fontan and 60% of non-Fontan patients. Fontan and non-Fontan patients alike are at risk for hepatic congestion and there is need for further evaluation to understand the clinical relevance of hepatic congestion caused right heart dysfunction.

Successful Fenestration of an Extracardiac Conduit in a Fontan Patient With the Baylis NRG RF Transeptal Needle and Creation of Fontan Fenestration with a 20-mm 535 Formula Stent

Successful Fenestration of an Extracardiac Conduit in a Fontan Patient With the Baylis NRG RF Transeptal Needle and Creation of Fontan Fenestration with a 20-mm 535 Formula Stent

Impact of Fontan Fenestration on Long-Term Outcomes: A Propensity Score-Matched Analysis.

BackgroundThe long‐term impact of fenestration at the time of Fontan operation remains unclear. We aimed to review the early and long‐term impact of Fontan fenestration in the Australia and New Zealand cohort.Methods and ResultsWe reviewed 1443 patients (621 fenestrated, 822 nonfenestrated) from the Australia and New Zealand Fontan registry. Data were collected on preoperative demographics, operative details, and follow‐up. Propensity‐score matching was performed to account for the various preoperative and operative differences and risk factors. Primary outcomes were survival and freedom from failure. Median follow‐up was 10.6 years. After propensity‐score matching (407 matched pairs), there was no difference in survival (87% versus 90% at 20 years; P=0.16) or freedom from failure (73% versus 80% at 20 years; P=0.10) between patients with and without fenestration, respectively. Although patients with fenestration had longer bypass and cross‐clamp times (P<0.001), there was no difference in hospital length of stay or prolonged pleural effusions (P=0.80 and P=0.46, respectively). Freedom from systemic and Fontan circuit thromboembolism was higher in the nonfenestrated group (89%; 95% CI, 88%–95%) than the fenestrated group (84%; 95% CI, 77%–89%; P=0.03). There was no difference in incidence of plastic bronchitis, protein‐losing enteropathy, New York Heart Association Class III/IV symptoms, or Fontan takedown.ConclusionsIn the propensity score–matched analysis we have demonstrated no difference in long‐term survival or freedom from Fontan failure in patients with and without fenestration. There was a higher incidence of long‐term thromboembolic events in patients with fenestration. Overall, it appears that fenestration in Fontan circulation does not bring long‐term benefits.

Invasive Hemodynamics in Asymptomatic Adult Fontan Patients and According to Different Clinical Phenotypes.

The correlation between hemodynamics and clinical phenotypes/symptoms in adults post Fontan procedure has not been well studied. Moreover, the "expected" hemodynamics in those who are asymptomatic remain unclear. This retrospective cohort included 155 adult patients post Fontan undergoing right and left cardiac catheterization between December 1999 and November 2017. Patients were categorized according to the primary indication for cardiac catheterization/clinical status, ie, fluid overload, atrial arrhythmia, exercise intolerance, abnormal liver imaging (in the absence of other indications), or asymptomatic. Underlying hemodynamics and survival were compared. Primary indications for cardiac catheterization were atrial arrhythmias in 49, fluid overload in 44, exercise intolerance in 37, and abnormal liver imaging in 13 patients; 12 patients were asymptomatic. The fluid overload and abnormal liver imaging groups had the highest median Fontan pressures, at 17 mm Hg (interquartile range [IQR], 14-21.8) and 17 mm Hg (IQR, 12.5-17), respectively. Among asymptomatic patients, median pulmonary artery wedge pressure was 8 mm Hg (IQR, 6-11.8) and median Fontan pressure was 13 mm Hg (IQR, 12-14.5). There was no difference in the prevalence of abnormalities of the Fontan circuit or ≥ moderate valvular regurgitation among groups. During a median follow-up of 5.3 years (IQR, 1.4-9.4), there were 48 deaths. Survival was the lowest in patients presenting with fluid overload (5-year survival, 55.6%); there were no deaths among asymptomatic patients. Asymptomatic adult Fontan patients typically have ventricular filling pressures <10 mm Hg and Fontan pressures <15 mm Hg and demonstrate excellent prognosis. Indication for catheterization predicted survival among our adult Fontan patients; the worst prognosis was noted among those presenting with fluid overload.

Fontan-associated liver disease.

Fontan-associated liver disease.

A Porthole on the Fontan Circuit

A Porthole on the Fontan Circuit

Prevalence of Venovenous Shunting and High-Output State Quantified with 4D Flow MRI in Patients with Fontan Circulation.

To assess the ability of four-dimensional (4D) flow MRI to quantify flow volume of the Fontan circuit, including the frequency and hemodynamic contribution of systemic-to-pulmonary venovenous collateral vessels. In this retrospective study, patients with Fontan circulation were included from three institutions (2017-2021). Flow measurements were performed at several locations along the circuit by two readers, and collateral shunt volumes were quantified. The frequency of venovenous collaterals and structural defects were tabulated from concurrent MR angiography, contemporaneous CT, or catheter angiography and related to Fontan clinical status. Statistical analysis included Pearson and Spearman correlation and Bland-Altman analysis. Seventy-five patients (mean age, 20 years; range, 5-58 years; 46 female and 29 male patients) were included. Interobserver agreement was high for aortic output, pulmonary arteries, pulmonary veins, superior vena cava (Glenn shunt), and inferior vena cava (Fontan conduit) (range, ρ = 0.913-0.975). Calculated shunt volume also showed strong agreement, on the basis of the difference between aortic and pulmonary flow (ρ = 0.935). A total of 37 of 75 (49%) of the patients exhibited shunts exceeding 1.00 L/min, 81% (30 of 37) of whom had pulmonary venous or atrial flow volume step-ups and corresponding venovenous collaterals. A total of 12% of patients (nine of 75) exhibited a high-output state (>4 L/min/m2), most of whom had venovenous shunts exceeding 30% of cardiac output. Fontan flow and venovenous shunting can be reliably quantified at 4D flow MRI; high-output states were found in a higher proportion of patients than expected, among whom venovenous collaterals were common and constituted a substantial proportion of cardiac output.Keywords: Pediatrics, MR Angiography, Cardiac, Technology Assessment, Hemodynamics/Flow Dynamics, Congenital Supplemental material is available for this article. © RSNA, 2021.

THE UNFORUNATE SEEDING OF TESTICULAR CHORIOCARCINOIMA FOLLOWING THE FONTAN PROCEDURE

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: The Fontan procedure is a palliative surgical procedure performed in children ages 2-4 years old with hypoplastic right heart syndrome by relocating the inferior vena cava from the right atrium to the right pulmonary artery to complete the Fontan circuit[1][2]. This circuit allows for normalization of arterial saturation and abolishment of chronic volume overload at the cost of decreased cardiac output.[1] This adjustment allows for almost all venous blood to return to heart through the right pulmonary artery[3]. We present a case below in a patient with hypoplastic right heart treated with the Fontan procedure who was later diagnosed with testicular choriocarcinoma with hematogenous metastasis through the right pulmonary artery. CASE PRESENTATION: An 18-year-old male with a past medical history of heterotaxia, hypoplastic right heart treated with Fontan palliation and Kawashima surgery initially presented for persistent, worsening dyspnea. On further questioning the patient reported an active lifestyle but over the past several weeks had begun to develop dyspnea with limited ambulation and persistent cough. On presentation, the patient was found to be in acute hypoxic respiratory failure. Computed tomography (CT) imaging of the chest, abdomen and pelvis showed a new large right retroperitoneal mass causing hydronephrosis as well as innumerable right sided pulmonary nodules concerning for metastatic disease. Biopsy of the retroperitoneal mass revealed germ cell tumor, with choriocarcinoma heavily present in the tissue. The patient underwent MRI of the brain for staging, which subsequently revealed numerous embolic strokes. He was started on a chemotherapy regimen of etoposide, ifosfamide, and cisplatin; however, his course was complicated by COVID-19 infection which caused further deterioration in his respiratory status. He unfortunately passed away from respiratory failure. DISCUSSION: In this case, the Fontan procedure provided the patient with excellent oxygenation as the patient was able to exercise and live relatively unbound by his complex cardiovascular history. However, this procedure served as the conduit that allowed his testicular choriocarcinoma to hematogenously spread and predominately seed his right lung. Hospitalization was further complicated by active COVID-19 infection and in concert with his poor lung status, the patient passed. CONCLUSIONS: This case highlights the unique anatomy and physiology of patients treated with the Fontan circulation. This life saving surgery performed in early childhood unfortunately served as the conduit for hematogenously spread of choriocarcinoma. As a consequence of the surgery, the right pulmonary artery receives all the venous return which then allowed the malignancy to spread predominately to the right lung. REFERENCE #1: Gewillig M. The Fontan Circulation. Heart. 2005;91:839-846 REFERENCE #2: Kutty S, Jacobs M, Thompson R, Danford D. Fontan Circulation of Next Generation: Why It's Necessary, What It May Look Like. JAHA. 2020;9:e01 3691 REFERENCE #3: Cowgill LD. The Fontan Procedure: A Historical Review. Ann Thoracic Surgery. 1991;51:1026-30 DISCLOSURES: No relevant relationships by Arjan Ahluwalia, source=Web Response No relevant relationships by Martin Delatorre, source=Web Response No relevant relationships by Kaitlyn Musco, source=Web Response No relevant relationships by Alina Zhu, source=Web Response

Non diagnosed PAPVC induce large reverse venovenous shunt after modified Fontan surgery: A case report of a rare anomaly and embolization therapy

Fontan operation is a reliable palliative surgery for patients with single ventricle physiology. Still, the development of complication is common; one of these complications that need to interventional approach is veno-venous collaterals between systemic and pulmonary veins. A 16-yearoldgirl with a history of modified Fontan operation at 9 years ago was referred with progressive cyanosis and dyspnea on exertion. In contrast trans-thoracic echocardiography (TTE), no fenestration was seen in Fontan circulation. Cardiac magnetic resonance revealed partial anomalous pulmonary vein connection (PAPVC) from left upper pulmonary vein to vertical vein and then into the in nominate vein and SVC with the reverse flow from superior vena cava (SVC) to left upper pulmonary vein(LUPV). This anomalous vein became severe engorged and tortuous. Possibly, LUPV and the verticalvein was dilated gradually as a result of increased pressure in the Fontan circuit. Finally, she underwent successful coil embolization in the midpart of the vertical vein. The oxygen saturation increased from80% to 93%.

Early Thromboprophylaxis Initiation is Associated With Reduced Fontan Thromboses in the Early Postoperative Period

Fontan circuit thrombosis is a significant cause of early postoperative morbidity and mortality. Thrombosis incidence and relationship to thromboprophylaxis choice and timing of initiation are not well established. We sought to evaluate the incidence of Fontan circuit thrombosis in the first 30 postoperative days and its relationship to thromboprophylaxis choice and timing. Patients undergoing Fontan surgery, 2006-2016, were reviewed. Fontan circuit thrombosis was defined by sonographic detection of intracardiac or deep venous thrombi. Logistic regression was used to assess relationships between thromboprophylaxis characteristics and thrombosis. One hundred ninety-two patients underwent Fontan. Fontan thrombosis occurred in 19 (10%) patients. 54% were started on aspirin, 27% coumadin, 4% heparin, and 7% none. There was no relationship between thrombosis and baseline anatomy, Fontan type or fenestration. Median time to thromboprophylaxis initiation was 4 days (interquartile range 2-6). Patients not started on thromboprophylaxis had 44.8 times the odds of thrombosis as those on thromboprophylaxis (confidence interval 6.4-311.7, P < 0.01); no children starting thromboprophylaxis before postoperative day 2 developed thromboses. For every day that thromboprophylaxis was delayed, odds of thrombosis increased by 30% (odds ratio 1.3; CI 1.1-1.6, P < 0.01). There was no difference in the odds of thrombosis between children taking aspirin vs other thromboprophylaxis types. Odds of early postoperative Fontan circuit thrombosis are increased in patients in whom thromboprophylaxis is delayed beyond the second postoperative day, with no difference in the odds of thrombosis between patients initiated on aspirin vs other thromboprophylaxis. Early aspirin institution post Fontan is recommended to reduce morbidity. Ultra-mini-Abstract: Odds of early postoperative Fontan circuit thrombosis are increased in patients in whom thromboprophylaxis is delayed beyond the second postoperative day, with no difference in the odds of thrombosis between patients initiated on aspirin vs other thromboprophylaxis. Early aspirin institution post Fontan is recommended to reduce morbidity and resource utilization.

Association of Lymphatic Abnormalities with Early Complications after Fontan Operation.

Background Increased central venous pressure is inherent in Fontan circulation but not strongly related to Fontan complication. Abnormalities of the lymphatic circulation may play a crucial role in early Fontan complications. Methods This was a retrospective, single-center study of patients undergoing Fontan operation from 2008 to 2015. The primary outcome was significant early Fontan complication defined as secondary in-hospital treatment due to peripheral edema, ascites, pleural effusions, protein-losing enteropathy, or plastic bronchitis. All patients received T2-weighted magnetic resonance images to assess abdominal and thoracic lymphatic perfusion pattern 6 months after Fontan completion with respect to localization, distribution, and extension of lymphatic perfusion pattern (type 1–4) and with application of an area score (0–12 points). Results Nine out of 42 patients developed early Fontan complication. Patients with complication had longer chest tube drainage (mean 28 [interquartile range [IQR]: 13–60] vs. 13 [IQR: 2–22] days, p = 0.01) and more often obstructions in the Fontan circuit 6 months after surgery (56 vs. 15%, p = 0.02). Twelve patients showed little or no abnormalities of lymphatic perfusion (lymphatic perfusion pattern type 1). Most frequently magnetic resonance imaging showed lymphatic congestion in the supraclavicular region (24/42 patients). Paramesenteric lymphatic congestion was observed in eight patients. Patients with early Fontan complications presented with higher lymphatic area score (6 [min–max: 2–10] vs. 2 [min–max: 0–8]), p = 0.001) and greater distribution and extension of thoracic lymphatic congestion (type 3–4: n = 5/9 vs. n = 1/33, p = 0.001). Conclusion Early Fontan complication is related to hemodynamic factors such as circuit obstruction and to the occurrence and extent of lymphatic congestion.

Cardiac function in pregnant women with a Fontan circulation following live birth

Abstract Background Fontan circuits are used to palliate congenital heart disease where patients have a single functioning ventricle. The venous return to the heart is redirected to the pulmonary arteries through the use of a conduit, bypassing the heart. Many females with Fontan circuits are now reaching child-bearing age and some desire pregnancy. However, pregnancy in women with Fontan circuits is associated with high complication rates. Purpose We compared postnatal cardiac function in women with a Fontan circulation with pre-pregnancy cardiovascular investigations. Methods Data were collected from case notes of all women with a Fontan circulation giving birth after 24 weeks of gestation at Birmingham Women's Hospital between 1997 and 2019. Results 18 women with a median age of 29±6 years were followed up for 8.0±9 years. There were 21 live births at a median gestation of 32±5 weeks, of which 81% were caesarean sections. Three infants (14%) were born before 30 weeks' gestation and only two (10%) at term. Significant dyspnoea complicated 19% of pregnancies and postpartum haemorrhage occurred in 24%. Pre-pregnancy cardiac magnetic resonance (CMR) data were available for 11 women and post-pregnancy for 14. Post-pregnancy scans were performed a median of 1.5±4.8 years after birth. Ejection fraction was 63.6±5% at baseline and tended to reduce following pregnancy (median −5.0±8%, n=7). Pre-pregnancy peak oxygen consumption (VO2max) was 73±14% of predicted on cardiopulmonary exercise testing. Median change in VO2max was −8±22% post-pregnancy (n=4). There was no change New York Heart Association (NYHA) class or resting saturations after pregnancy. Conclusions Preterm delivery and maternal bleeding were prevalent in this cohort. Exercise capacity was moderately impaired and saturations were typically low. Pregnancy does not seem to have longer term impact on oxygen saturations or NYHA class. Larger series are needed to confirm whether pregnancy is detrimental to postpartum systolic function. CMR can give comprehensive assessment of cardiac function before and after pregnancy and provide data to inform the crucial pre-pregnancy counselling for Fontan patients of child-bearing age. Funding Acknowledgement Type of funding source: None

Identification of high-risk Fontan candidates by intraoperative pulmonary flow study

BackgroundPre-Fontan risk stratification is still less than optimal. We aimed to evaluate the effectiveness of intraoperative pulmonary flow study (IOFS), in combination with conventional preoperative evaluation, in the identification of high-risk candidates for the Fontan operation. MethodData from 37 patients (age: 38.1 ± 4.9 months) who underwent the Fontan operation with IOFS were retrospectively reviewed. After anastomosing the Gore-Tex vascular graft to the confluent pulmonary artery, IOFS was performed through the graft at various cardiac indices (CI) (1–4 L/min/m2) generated from a roller pump. Mean pulmonary artery pressure (mPAP) and left atrial pressure (LAP) were recorded. The patients were divided into two groups: those who required Fontan circuit fenestration (group Ff) and those who did not (group Fn). ResultsEleven patients (29.7%) required fenestration, intraoperatively (n = 4) and postoperatively (n = 7), due to hemodynamic instability. Heterotaxy syndrome (P = 0.005) and atrioventricular valvar regurgitation (P = 0.04) were more frequent, and ventricle posterior wall thickness (VPWT) was higher (P = 0.024) in group Ff. On IOFS, the increase in mPAP by CI was sharper in group Ff than in group Fn (P < 0.001) owing to an increase in LAP. On multivariable analysis, mPAP at a CI of 3.0 L/min/m2 from IOFS was the only predictor of fenestration and correlated with preoperative VPWT (R = 0.543, P = 0.001). ConclusionsIOFS may be helpful to identify high-risk Fontan candidates, and high mPAP at CI of 3.0 L/min/m2 on IOFS is a significant predictor of the requirement for fenestration. VPWT is an important preoperative risk factor which correlates with the IOFS results.