Dobutamine stress testing for the evaluation of atrial and diastolic ventricular function in Fontan patients.

OBJECTIVE: To assess the atrial and ventricular diastolic function response to dobutamine stress in Fontan patients, and to relate these measurements to exercise capacity and events during the follow-up. METHODS: We performed a secondary analysis of a cross-sectional multicentre study of Fontan patients with intra-atrial lateral tunnel (ILT) or extracardiac conduit (ECC) modification. Subjects underwent cardiac MRI during rest and low-dose dobutamine stress, and cardiopulmonary exercise testing. Atrial and diastolic ventricular function parameters were derived from volume-time curves.Medical records were abstracted for a composite end-point of death, listing for transplant, arrhythmia and reintervention. Spearman's r correlation tests and Cox proportional hazards models were used to assess the relation between the dobutamine response for atrial and diastolic ventricular function and outcomes, including exercise capacity. RESULTS: We included 57 patients (26 ECC; 31 ILT) aged 12.8 (IQR (10.3-15.5)) years. During dobutamine stress atrial cyclic volume change increased (3.0 (0.4-5.9) mL/m2, p<0.001), as did early (1.9 (-1.6 to 3.6) mL/m2, p=0.001) and late emptying volume (2.2 (0.2-4.4) mL/m2, p<0.001).Ventricular early filling decreased (-1.6 (-5.7 to 0.7) mL/m2,p=0.046) and ventricular late filling increased (1.0 (-0.4 to 3.4) mL/m2,p<0.001) while stroke volume remained similar.Only for patients with the ECC modification, atrial early emptying volume increase correlated with peak oxygen uptake (ρ=0.66,p=0.002). No other parameter related to exercise capacity.During a median 7.1-year follow-up, 22 patients reached the composite endpoint. No parameter predicted events during the follow-up. CONCLUSIONS: Dobutamine stress augmented atrial reservoir and pump function for Fontan patients. Atrial early emptying reserve related to exercise capacity in ECC patients. No other atrial or diastolic ventricular function parameter related to outcomes.

Associations Between Blood Biomarkers, Cardiac Function, and Adverse Outcome in a Young Fontan Cohort.

Background Patients who have undergone the Fontan procedure are at high risk of circulatory failure. In an exploratory analysis we aimed to determine the prognostic value of blood biomarkers in a young cohort who have undergone the Fontan procedure. Methods and Results In multicenter prospective studies patients who have undergone the Fontan procedure underwent blood sampling, cardiopulmonary exercise testing, and stress cardiac magnetic resonance imaging. Several biomarkers including NT-proBNP (N-terminal pro-B-type natriuretic peptide), GDF-15 (growth differentiation factor 15), Gal-3 (galectin-3), ST2 (suppression of tumorigenicity 2), DLK-1 (protein delta homolog 1), FABP-4 (fatty acid-binding protein 4), IGFBP-1 (insulin-like growth factor-binding protein 1), IGFBP-7, MMP-2 (matrix metalloproteinase 2), and vWF (von Willebrand factor) were assessed in blood at 9.6 (7.1-12.1) years after Fontan completion. After this baseline study measurement, follow-up information was collected on the incidence of adverse cardiac events, including cardiac death, out of hospital cardiac arrest, heart transplantation (listing), cardiac reintervention (severe events), hospitalization, and cardioversion/ablation for arrhythmias was collected and the relation with blood biomarkers was assessed by Cox proportional hazard analyses. The correlation between biomarkers and other clinical parameters was evaluated. We included 133 patients who have undergone the Fontan procedure, median age 13.2 (25th, 75th percentile 10.4-15.9) years, median age at Fontan 3.2 (2.5-3.9) years. After a median follow-up of 6.2 (4.9-6.9) years, 36 (27.1%) patients experienced an event of whom 13 (9.8%) had a severe event. NT-proBNP was associated with (all) events during follow-up and remained predictive after correction for age, sex, and dominant ventricle (hazard ratio, 1.89; CI, 1.32-2.68). The severe event-free survival was better in patients with low levels of GDF-15 (P=0.005) and vWF (P=0.008) and high levels of DLK-1 (P=0.041). There was a positive correlation (ß=0.33, P=0.003) between DLK-1 and stress cardiac magnetic resonance imaging functional reserve. Conclusions NT-proBNP, GDF-15, vWF, DLK-1, ST-2 FABP-4, and IGFBP-7 levels relate to long-term outcome in young patients who have undergone the Fontan procedure.

Atrial function in Fontan patients assessed by CMR: Relation with exercise capacity and long-term outcomes.

OBJECTIVE: To assess the role of atrial function on exercise capacity and clinical events in Fontan patients. DESIGN: We included 96 Fontan patients from 6 tertiary centers, aged 12.8 (IQR 10.1-15.6) years, who underwent cardiac magnetic resonance imaging and cardiopulmonary exercise testing within 12 months of each other from 2004 to 2017. Intra-atrial lateral tunnel (ILT) and extracardiac conduit (ECC) patients were matched 1:1 with regard to age, gender and dominant ventricle. The pulmonary venous atrium was manually segmented in all phases and slices. Atrial function was assessed by volume-time curves. Furthermore, atrial longitudinal and circumferential feature tracking strain was assessed. We determined the relation between atrial function and exercise capacity, assessed by peak oxygen uptake and VE/VCO2 slope, and events (mortality, listing for transplant, re-intervention, arrhythmia) during follow-up. RESULTS: Atrial maximal and minimal volumes did not differ between ILT and ECC patients. ECC patients had higher reservoir function (21.1 [16.4-28.0]% vs 18.2 [10.9-22.2]%, p = .03), lower conduit function and lower total circumferential strain (13.8 ± 5.1% vs 18.0 ± 8.7%, p = .01), compared to ILT patients. Only for ECC patients, a better late peak circumferential strain rate predicted better VE/VCO2 slope. No other parameter of atrial function predicted peak oxygen uptake or VE/VCO2 slope. During a median follow-up of 6.2 years, 42 patients reached the composite end-point. No atrial function parameters predicted events during follow-up. CONCLUSIONS: ECC patients have higher atrial reservoir function and lower conduit function. Atrial function did not predict exercise capacity or events during follow-up.

Staged total cavopulmonary connection: serial comparison of intra-atrial lateral tunnel and extracardiac conduit taking account of current surgical adaptations.

OBJECTIVES: Our goals were to compare the outcome of the intra-atrial lateral tunnel (ILT) and the extracardiac conduit (ECC) techniques for staged total cavopulmonary connection (TCPC) and to compare the current modifications of the TCPC technique, i.e. the prosthetic ILT technique with the current ECC technique with a ≥18-mm conduit. METHODS: We included patients who had undergone a staged TCPC between 1988 and 2008. Records were reviewed for patient demographics, operative details and events during follow-up (death, surgical and catheter-based reinterventions and arrhythmias). RESULTS: Of the 208 patients included, 103 had the ILT (51 baffle, 52 prosthetic) technique and 105 had the ECC technique. Median follow-up duration was 13.2 years (interquartile range 9.5-16.3). At 15 years after the TCPC, the overall survival rate was comparable (81% ILT vs 89% ECC; P = 0.12). Freedom from late surgical and catheter-based reintervention was higher for patients who had ILT than for those who had ECC (63% vs 44%; P = 0.016). However, freedom from late arrhythmia was lower for patients who had ILT than for those who had ECC (71% vs 85%, P = 0.034). In a subgroup of patients who had the current TCPC technique, when we compared the use of a prosthetic ILT with ≥18-mm ECC, we found no differences in freedom from late arrhythmias (82% vs 86%, P = 0.64) or in freedom from late reinterventions (70% vs 52%, P = 0.14). CONCLUSIONS: A comparison between the updated prosthetic ILT and current ≥18-mm ECC techniques revealed no differences in late arrhythmia-free survival or late reintervention-free survival. Overall, outcomes after the staged TCPC were relatively good and reinterventions occurred more frequently in the ECC group, whereas late arrhythmias were more common in the ILT group.

Long-Term Serial Follow-Up of Pulmonary Artery Size and Wall Shear Stress in Fontan Patients.

Pulmonary arterial (PA) flow is abnormal after the Fontan operation and is marked by a lack of pulsatility. We assessed the effects of this abnormal flow on the size and function of the PA's in Fontan patients in long-term serial follow-up. Twenty-three Fontan patients with serial follow-up were included. Median age was 11.1 (9.5-16.0) years at baseline and 15.5 (12.5-22.7) years at follow-up. Median follow-up duration was 4.4 (4.0-5.8) years. Flow and size of the left pulmonary artery were determined using phase-contrast MRI. From this wall shear stress (WSS), distensibility and pulsatility were determined. A group of healthy peers was included for reference. Flow and pulsatility were significantly lower in patients than in controls (p < 0.001). Mean area was comparable in patients and controls, but distensibility was significantly higher in controls (p < 0.001). Mean and peak WSS were significantly lower in Fontan patients (p < 0.001). Between baseline and follow-up, there was a significant increase in normalized flow (15.1 (14.3-19.1) to 18.7 (14.0-22.6) ml/s/m(2), p = 0.023). Area, pulsatility, distensibility and WSS did not change, but there was a trend toward a lower mean WSS (p = 0.068). Multivariable regression analysis showed that flow, area and age were important predictors for WSS. WSS in Fontan patients is decreased compared to healthy controls and tends to decrease further with age. Pulsatility and distensibility are significantly lower compared to healthy controls. Pulmonary artery size, however, is not significantly different from healthy controls and long-term growth after Fontan operation is proportionate to body size.

Does functional health status predict health-related quality of life in children after Fontan operation?

PURPOSE: It is important to identify those children with a Fontan circulation who are at risk for impaired health-related quality of life. We aimed to determine the predictive value of functional health status - medical history and present medical status - on both physical and psychosocial domains of health-related quality of life, as reported by patients themselves and their parents. METHODS: We carried out a prospective cross-sectional multi-centre study in Fontan patients aged between 8 and 15, who had undergone staged completion of total cavopulmonary connection according to a current technique before the age of 7 years. Functional health status was assessed as medical history - that is, age at Fontan, type of Fontan, ventricular dominance, and number of cardiac surgical procedures - and present medical status - assessed with magnetic resonance imaging, exercise testing, and rhythm assessment. Health-related quality of life was assessed with The TNO/AZL Child Questionnaire Child Form and Parent Form. RESULTS: In multivariate prediction models, several medical history variables, such as more operations post-Fontan completion, lower age at Fontan completion, and dominant right ventricle, and present medical status variables, such as smaller end-diastolic volume, a higher score for ventilatory efficiency, and the presence of sinus node dysfunction, predicted worse outcomes on several parent-reported and self-reported physical as well as psychosocial health-related quality of life domains. CONCLUSIONS: Medical history and worse present medical status not only predicted worse physical parent-reported and self-reported health-related quality of life but also worse psychosocial health-related quality of life and subjective cognitive functioning. These findings will help in identifying patients who are at risk for developing impaired health-related quality of life.

Regional ventricular performance and exercise training in children and young adults after repair of tetralogy of Fallot: randomized controlled pilot study.

BACKGROUND: Public-health guidelines recommend patients with congenital heart disease to exercise. Studies have shown that patients with congenital heart disease can improve physical exercise capacity. The effect of training on regional ventricular performance has hardly been studied. We performed a pilot study to assess whether an exercise training program would result in adverse changes of regional ventricular performance in patients with corrected tetralogy of Fallot. METHODS AND RESULTS: Multicenter prospective randomized controlled pilot study in patients with tetralogy of Fallot aged 10 to 25 years. A 12-week standardized aerobic dynamic exercise training program (3 one-hour sessions per week) was used. Pre- and post-training cardiopulmonary exercise tests, MRI, and echocardiography, including tissue-Doppler imaging, were performed. Patients were randomized to the exercise group (n=28) or control group (n=20). One patient in the exercise group dropped out. Change in tissue-Doppler imaging parameters was similar in the exercise group and control group (change in right ventricle free wall peak velocity E' exercise group, 0.8±2.6 cm/s; control group, 0.9±4.1; peak velocity A' exercise group, 0.4±2.4 m/s; control group 4.6±18.1 cm/s). CONCLUSIONS: This randomized controlled pilot study provides preliminary data suggesting that regional ventricular performance is well maintained during 3-month aerobic dynamic exercise training in children and young adults with repaired tetralogy of Fallot. This information might help patients adhere to current public-health guidelines. CLINICAL TRIAL REGISTRATION: URL: http//:www.trialregister.nl. Unique identifier: NTR2731.

Comprehensive rhythm evaluation in a large contemporary Fontan population.

OBJECTIVES: Rhythm disturbances are an important cause of morbidity in Fontan patients. Currently, the total cavopulmonary connection is performed by using the intra-atrial lateral tunnel (ILT) ('baffle ILT' or 'prosthetic ILT'), or the extracardiac conduit (ECC). The aim of the study was to evaluate rhythm abnormalities and compare the surgical techniques in a contemporary cohort. METHODS: In a cross-sectional multicentre study, 115 patients (age 12.5 ± 3.1 years) underwent rhythm evaluation using ECG, exercise testing and Holter, including heart rate variability. Medical history was reviewed for episodes of arrhythmia. RESULTS: Sinus node dysfunction (SND) was found in 29%, 3 of whom required pacemaker therapy. No difference was found in the incidence of SND between ILT and ECC patients. Sinus pauses occurred only in the ILT group. Exercise testing showed no difference in peak heart rate between the groups. Heart rate reserve (P = 0.023) and heart rate recovery (HRrecovery) (P < 0.001) were lower in ILT patients. Atrial arrhythmias were more common in ILT patients (15 vs 1%, P = 0.004), but only in those with a baffle ILT. One patient had symptomatic ventricular tachycardia (VT). Holter recordings showed sub-clinical VT in 6% of patients, which was associated with larger end-diastolic (P = 0.035) and end-systolic volumes (P = 0.029). CONCLUSIONS: The overall incidence of arrhythmia was low, although SND was frequently present in both Fontan groups. ILT patients had slower HRrecovery, and ILT patients with the more extensive baffle technique had more atrial arrhythmias and more sinus pauses. The significance of asymptomatic ventricular arrhythmias in this young population remains to be determined.

Computational fluid dynamics in Fontan patients to evaluate power loss during simulated exercise.

OBJECTIVE: Exercise intolerance is common in total cavopulmonary connection (TCPC) patients. It has been suggested that power loss (Ploss) inside the TCPC plays a role in reduced exercise performance. Our objective is to establish the role of Ploss inside the TCPC during increased flow, simulating exercise in a patient-specific way. METHODS: Cardiac MRI (CMR) was used to obtain flow rates from the caval veins during rest and increased flow, simulating exercise with dobutamine. A 3D reconstruction of the TCPC was created using CMR data. Computational fluid dynamics (CFD) simulations were performed to calculate Ploss inside the TCPC structure for rest and stress conditions. To reflect the flow distribution during exercise, a condition where inferior caval vein (IVC) flow was increased twofold compared with rest was added. 29 TCPC patients (15 intra-atrial lateral tunnel (ILT) and 14 extracardiac conduit (ECC)) were included. RESULTS: Mean Ploss at rest was 1.36 ± 0.94 (ILT) and 3.20 ± 1.26 (ECC) mW/m(2) (p<0.001), 2.84 ±1.95 (ILT) and 8.41 ± 3.77 (ECC) mW/m(2) (p<0.001) during dobutamine and 5.21 ± 3.50 (ILT) and 15.28 ± 8.30 (ECC) mW/m(2) (p=0.001) with twofold IVC flow. The correlation between cardiac index and Ploss was exponential (ILT: R(2)=0.811, p<0.001; ECC: R(2)=0.690, p<0.001). CONCLUSIONS: Ploss inside the TCPC structure is limited but increases with simulated exercise. This relates to the anatomy of TCPC and the surgical technique used. In all flow conditions, ILT patients have lower Ploss than ECC patients. We did not find a relationship between Ploss and exercise capacity.

Exercise capacity in children after total cavopulmonary connection: lateral tunnel versus extracardiac conduit technique.

OBJECTIVES: In patients with univentricular heart disease, the total cavopulmonary connection (TCPC) is the preferred treatment. TCPC can be performed using the intra-atrial lateral tunnel (ILT) or extracardiac conduit (ECC) technique. The purpose of the present study was to evaluate exercise capacity in contemporary TCPC patients and compare the results between the 2 techniques. METHODS: A total of 101 TCPC patients (ILT, n=42; ECC, n=59; age, 12.2±2.6 years; age at TCPC completion, 3.2±1.1 years) underwent cardiopulmonary exercise testing. The patients were recruited prospectively from 5 tertiary referral centers. RESULTS: For the entire group, the mean peak oxygen uptake was 74%±14%, peak heart rate was 90%±8%, peak workload was 62%±13%, and slope of ventilation versus carbon dioxide elimination (VE/VCO2 slope) was 127%±30% of the predicted value. For the ILT and ECC groups, patient age, age at TCPC completion, body surface area, peak workload, and peak heart rate were comparable. The percentage of predicted peak oxygen uptake was lower in the ILT group (70%±12% vs 77%±15%; P=.040), and the percentage of predicted VE/VCO2 slope was greater in the ILT group (123%±36% vs 108%±14%; P=.015). In a subgroup analysis that excluded ILT patients with baffle leak, these differences were not statistically significant. CONCLUSIONS: Common exercise parameters were impaired in contemporary Fontan patients. Chronotropic incompetence was uncommon. The peak oxygen uptake and VE/VCO2 slope were less favorable in ILT patients, likely related to baffle leaks in some ILT patients. These results have shown that a reduced exercise capacity in Fontan patients remains an important issue in contemporary cohorts. The ECC had a more favorable exercise outcome at medium-term follow-up.