Transcatheter Repair for Patients with Tricuspid Regurgitation.

BACKGROUND: Severe tricuspid regurgitation is a debilitating condition that is associated with substantial morbidity and often with poor quality of life. Decreasing tricuspid regurgitation may reduce symptoms and improve clinical outcomes in patients with this disease. METHODS: We conducted a prospective randomized trial of percutaneous tricuspid transcatheter edge-to-edge repair (TEER) for severe tricuspid regurgitation. Patients with symptomatic severe tricuspid regurgitation were enrolled at 65 centers in the United States, Canada, and Europe and were randomly assigned in a 1:1 ratio to receive either TEER or medical therapy (control). The primary end point was a hierarchical composite that included death from any cause or tricuspid-valve surgery; hospitalization for heart failure; and an improvement in quality of life as measured with the Kansas City Cardiomyopathy Questionnaire (KCCQ), with an improvement defined as an increase of at least 15 points in the KCCQ score (range, 0 to 100, with higher scores indicating better quality of life) at the 1-year follow-up. The severity of tricuspid regurgitation and safety were also assessed. RESULTS: A total of 350 patients were enrolled; 175 were assigned to each group. The mean age of the patients was 78 years, and 54.9% were women. The results for the primary end point favored the TEER group (win ratio, 1.48; 95% confidence interval, 1.06 to 2.13; P = 0.02). The incidence of death or tricuspid-valve surgery and the rate of hospitalization for heart failure did not appear to differ between the groups. The KCCQ quality-of-life score changed by a mean (±SD) of 12.3±1.8 points in the TEER group, as compared with 0.6±1.8 points in the control group (P<0.001). At 30 days, 87.0% of the patients in the TEER group and 4.8% of those in the control group had tricuspid regurgitation of no greater than moderate severity (P<0.001). TEER was found to be safe; 98.3% of the patients who underwent the procedure were free from major adverse events at 30 days. CONCLUSIONS: Tricuspid TEER was safe for patients with severe tricuspid regurgitation, reduced the severity of tricuspid regurgitation, and was associated with an improvement in quality of life. (Funded by Abbott; TRILUMINATE Pivotal ClinicalTrials.gov number, NCT03904147.).

Fontan Geometry and Hemodynamics Are Associated With Quality of Life in Adolescents and Young Adults.

BACKGROUND: Despite favorable short-term outcomes, Fontan palliation is associated with comorbidities and diminished quality of life (QOL) in the years after completion. We hypothesized that poor Fontan hemodynamics and ventricular function are associated with worse QOL. METHODS: This was a single-center study of Fontan survivors aged more than 12 years. Subjects completed a cardiac magnetic resonance scan and QOL questionnaire. Cardiac magnetic resonance-derived variables included Fontan geometry, and hemodynamics. Computational fluid dynamics simulations quantified power loss, pressure drop, and total cavopulmonary connection resistance across the Fontan. Quality of life was assessed by completion of the Pediatric Quality of Life Inventory. Longitudinal and cross-sectional comparisons were made between cardiac magnetic resonance and computational fluid dynamics parameters with patient-reported QOL. RESULTS: We studied 77 Fontan patients, median age 19.7 years (interquartile range, 17.1 to 23.6), median time from Fontan completion 16 years (interquartile range, 13 to 20). Longitudinal data were available for 48 patients; median time between cardiac magnetic resonance and QOL was 8.1 years (interquartile range, 7 to 9.4). Median patient-reported Pediatric Quality of Life Inventory total score was 80 (interquartile range, 67.4 to 88). Greater power loss and smaller left pulmonary artery diameter at baseline were associated with worse QOL at follow-up. Greater pressure drop was associated with worse QOL at the same time point. CONCLUSIONS: For Fontan survivors, measures of computational fluid dynamics hemodynamics and geometry are associated with worse QOL. Interventional strategies targeted at optimizing the Fontan may improve QOL.

The role of flow stasis in transcatheter aortic valve leaflet thrombosis.

OBJECTIVE: With the recent expanded indication for transcatheter aortic valve replacement to low-risk surgical patients, thrombus formation in the neosinus is of particular interest due to concerns of reduced leaflet motion and long-term transcatheter heart valve durability. Although flow stasis likely plays a role, a direct connection between neosinus flow stasis and thrombus severity is yet to be established. METHODS: Patients (n = 23) were selected to minimize potential confounding factors related to thrombus formation. Patient-specific 3-dimensional reconstructed in vitro models were created to replicate in vivo anatomy and valve deployment using the patient-specific cardiac output and idealized coronary flows. Dye was injected into each neosinus to quantify washout time as a measure of flow stasis. RESULTS: Flow stasis (washout time) showed a significant, positive correlation with thrombus volume in the neosinus (rho = 0.621, P < .0001). Neither thrombus volume nor washout time was significantly different in the left, right, and noncoronary neosinuses (P ≥ .54). CONCLUSIONS: This is the first patient-specific study correlating flow stasis with thrombus volume in the neosinus post-transcatheter aortic valve replacement across multiple valve types and sizes. Neosinus-specific factors create hemodynamic and thrombotic variability within individual patients. Measurement of neosinus flow stasis may guide strategies to improve outcomes in transcatheter aortic valve replacement.

Transcatheter Edge-to-Edge Repair for Treatment of Tricuspid Regurgitation.

BACKGROUND: Tricuspid regurgitation (TR) is a frequent disease with a progressive increase in mortality as disease severity increases. Transcatheter therapies for treatment of TR may offer a safe and effective alternative to surgery in this high-risk population. OBJECTIVES: The purpose of this report was to study the 1-year outcomes with the TriClip transcatheter tricuspid valve repair system, including repair durability, clinical benefit and safety. METHODS: The TRILUMINATE trial (n = 85) is an international, prospective, single arm, multicenter study investigating safety and performance of the TriClip Tricuspid Valve Repair System in patients with moderate or greater TR. Echocardiographic assessment was performed by a core laboratory. RESULTS: At 1 year, TR was reduced to moderate or less in 71% of subjects compared with 8% at baseline (p < 0.0001). Patients experienced significant clinical improvements in New York Heart Association (NYHA) functional class I/II (31% to 83%, p < 0.0001), 6-minute walk test (272.3 ± 15.6 to 303.2 ± 15.6 meters, p = 0.0023) and Kansas City Cardiomyopathy Questionnaire (KCCQ) score (improvement of 20 ± 2.61 points, p < 0.0001). Significant reverse right ventricular remodeling was observed in terms of size and function. The overall major adverse event rate and all-cause mortality were both 7.1% at 1 year. CONCLUSION: Transcatheter tricuspid valve repair using the TriClip device was found to be safe and effective in patients with moderate or greater TR. The repair itself was durable at reducing TR at 1 year and was associated with a sustained and marked clinical benefit with low mortality after 1 year in a fragile population that was at high surgical risk. (TRILUMINATE Study With Abbott Transcatheter Clip Repair System in Patients With Moderate or Greater TR; NCT03227757).

Non-Newtonian Effects on Patient-Specific Modeling of Fontan Hemodynamics.

The Fontan procedure is a common palliative surgery for congenital single ventricle patients. In silico and in vitro patient-specific modeling approaches are widely utilized to investigate potential improvements of Fontan hemodynamics that are related to long-term complications. However, there is a lack of consensus regarding the use of non-Newtonian rheology, warranting a systematic investigation. This study conducted in silico patient-specific modeling for twelve Fontan patients, using a Newtonian and a non-Newtonian model for each patient. Differences were quantified by examining clinically relevant metrics: indexed power loss (iPL), indexed viscous dissipation rate (iVDR), hepatic flow distribution (HFD), and regions of low wall shear stress (AWSS). Four sets of "non-Newtonian importance factors" were calculated to explore their effectiveness in identifying the non-Newtonian effect. No statistical differences were observed in iPL, iVDR, and HFD between the two models at the population-level, but large inter-patient variations exist. Significant differences were detected regarding AWSS, and its correlations with non-Newtonian importance factors were discussed. Additionally, simulations using the non-Newtonian model were computationally faster than those using the Newtonian model. These findings distinguish good importance factors for identifying non-Newtonian rheology and encourage the use of a non-Newtonian model to assess Fontan hemodynamics.

Y-graft modification to the Fontan procedure: Increasingly balanced flow over time.

OBJECTIVE: The use of Y-grafts for Fontan completion is hypothesized to offer more balanced hepatic flow distribution (HFD) and decreased energy losses. The purpose of this study was to evaluate the hemodynamic performance of Y-grafts over time using serial cardiac magnetic resonance data and to compare their performance with extracardiac Fontan connections. METHODS: Ten Fontan patients with commercially available Y-graft connections and serial postoperative cardiac magnetic resonance data were included in this study. Patient-specific computational fluid dynamics simulations were used to estimate HFD and energy losses. Y-graft performance was compared with 3 extracardiac conduit Fontan groups (n = 10 for each) whose follow-up times straddle the Y-graft time points. RESULTS: Y-graft HFD became significantly more balanced over time (deviation from 50% decreased from 18% ± 14% to 8% ± 8%; P = .015). Total cavopulmonary connection resistance did not significantly change. Y-grafts at 3-year follow-up showed more balanced HFD than the extracardiac conduit groups at both the earlier and later follow-up times. Total cavopulmonary connection resistance was not significantly different between any Y-graft or extracardiac conduit group. CONCLUSIONS: Y-grafts showed significantly more balanced HFD over a 3-year follow-up without an increase in total cavopulmonary connection resistance, and therefore may be a valuable option for Fontan completion. Additional follow-up data at longer follow-up times are still needed to thoroughly characterize the potential advantages of Y-graft use.

Cross-Sectional Magnetic Resonance and Modeling Comparison From Just After Fontan to the Teen Years.

BACKGROUND: Little is known of baseline anatomic, hemodynamic, and fluid dynamic cardiac magnetic resonance data in single-ventricle patients immediately after Fontan. A comparison from that time point to the teen years can demonstrate clinical course, potentially predict future events, and may shed some light regarding how to optimize outcome. This cross-sectional study is meant to characterize these variables from just after Fontan to the teenage years. METHODS: The anatomy, flows, and computational fluid dynamic modeling of 22 patients 3 to 9 months after Fontan (age 3 ± 1.1 years) and 25 teens (age 16 ± 1.8 years) were compared. Significance was defined as P less than .05. RESULTS: The percentage of Fontan pathway stenosis was greater with cardiac index and fenestration flow while caval return was lower in teens than in younger patients (for Fontan pathway stenosis, 43% vs 21%, P = .009); however, hepatic flow distribution was more evenly distributed in older patients. Pulmonary artery size kept up with somatic growth. In the teen group, indexed power loss (R = .39), percentage of Fontan pathway stenosis (R = .62), and particle resident time (R = .42) deteriorated as time from Fontan increased (P < .04 for all). CONCLUSIONS: There are mostly aspects of deterioration with a few bright spots of stability in anatomy, blood flow, and fluid dynamic variables in Fontan patients from the postoperative period to the teenage years. Most notably, Fontan pathway stenosis increases with decreasing flows while pulmonary artery size and hepatic flow distribution remain stable or improved. These data may be aid in designing improved Fontan reconstruction to optimize clinical outcome and to understand future complications.

Impact of Free-Breathing Phase-Contrast MRI on Decision-Making in Fontan Surgical Planning.

Fontan surgical planning ranks proposed surgical options according to their hemodynamics assessed by computational fluid dynamic (CFD) modeling. CFD commonly utilizes blood flow acquired under breath-holding (BH) conditions. Ignoring the free-breathing (FB) effect on blood flow waveforms may impact the ranking of surgical options. This study investigates such a potential impact by including ten Fontan patients who had blood flow acquisitions under both BH and FB conditions. A virtual surgery platform was used to generate two surgical options for each patient: (1) a traditional Fontan conduit and (2) a Y-graft. These options were ranked based on clinically relevant hemodynamic metrics: power loss (PL) and hepatic flow distribution (HFD). No difference was found in the ranking of options between using FB and BH flow acquisitions. The findings indicated that decision-making is not affected by the types of flow acquisition for Fontan surgical planning.

Cardiac Magnetic Resonance-Derived Metrics Are Predictive of Liver Fibrosis in Fontan Patients.

BACKGROUND: Liver fibrosis is a serious complication of single ventricle Fontan survivors. Its causes are of great interest, and potential solutions to halt or delay progression are needed. The purpose of this study is to investigate if prior hemodynamics and anatomy can predict liver fibrosis severity in these patients. METHODS: Twenty-one Fontan patients with cardiac magnetic resonance (CMR) data obtained greater than 1 year before liver biopsy data were included. Computational fluid dynamic simulations were performed to quantify total cavopulmonary connection (TCPC) flow dynamics using patient-specific anatomies and blood flow waveforms reconstructed from CMR data. Collagen deposition (a measure of liver fibrosis) was quantified by digital image analysis of Sirius red-stained slides. Statistical analyses were performed to investigate potential relationships between Fontan hemodynamics and liver fibrosis. RESULTS: With an average time of 6.7 ± 2.9 years (range, 2-11 years) between CMR and biopsy, TCPC resistance and left pulmonary artery stenosis showed significant, positive correlations with magnitude of liver fibrosis (r = 0.54, P = .026; and r = 0.55, P = .028, respectively). The change in inferior vena cava flow rate over time also showed a significant positive correlation with magnitude of liver fibrosis (r = 0.91, P = .001). CONCLUSIONS: TCPC resistance, left pulmonary artery stenosis, and increased inferior vena cava flow are positively associated with liver fibrosis after Fontan operation and hold promise as important predictors of hepatic decline. These findings encourage preprocedural planning and interventional strategies to improve TCPC performance and reduce vessel stenosis. Further investigation is warranted to design the ideal Fontan circulation and optimize flow dynamics to reduce the risk of liver fibrosis.

The first cohort of prospective Fontan surgical planning patients with follow-up data: How accurate is surgical planning?

OBJECTIVE: Fontan surgical planning is an image-based, collaborative effort, which is hypothesized to result in improved patient outcomes. A common motivation for Fontan surgical planning is the progression (or concern for progression) of pulmonary arteriovenous malformations. The purpose of this study was to evaluate the accuracy of surgical planning predictions, specifically hepatic flow distribution (HFD), a known factor in pulmonary arteriovenous malformation progression, and identify methodological improvements needed to increase prediction accuracy. METHODS: Twelve single-ventricle patients who were enrolled in a surgical planning protocol for Fontan surgery with pre- and postoperative cardiac imaging were included in this study. Computational fluid dynamics were used to compare HFD in the surgical planning prediction and actual postoperative conditions. RESULTS: Overall, HFD prediction error was 17 ± 13%. This error was similar between surgery types (15 ± 18% and 18 ± 10% for revisions vs Fontan completions respectively; P = .73), but was significantly lower (6 ± 7%; P = .05) for hepatic to azygous shunts. Y-grafts and extracardiac conduits showed a strong correlation between prediction error and discrepancies in graft insertion points (r = 0.99; P < .001). Improving postoperative anatomy prediction significantly reduced overall HFD prediction error to 9 ± 6% (P = .03). CONCLUSIONS: Although Fontan surgical planning can offer accurate HFD predictions for specific graft types, methodological improvements are needed to increase overall accuracy. Specifically, improving postoperative anatomy prediction was shown to be an important target for future work. Future efforts and refinements to the surgical planning process will benefit from an improved understanding of the current state and will rely heavily on increased follow-up data.

An in vitro analysis of the PediMag and CentriMag for right-sided failing Fontan support.

OBJECTIVE: Right-sided mechanical circulatory support for failing Fontan physiology has been largely unsuccessful due to inherent hemodynamic differences between these patients and the target populations for most assist devices. This study uses advanced benchtop modeling of Fontan physiology to examine the use of PediMag and CentriMag to improve failing Fontan hemodynamics. METHODS: Each device was attached to a compliance-matched, patient-specific total cavopulmonary connection in vitro model that used resistances, compliances, and programmable waveforms to establish "failing Fontan" baseline hemodynamics (cardiac output [CO] = 3.5 L/min and central venous pressure ∼17 mm Hg). The ability of the assist devices to improve failing Fontan hemodynamics (reduce inferior vena cava pressure and augment CO) was investigated. RESULTS: Requiring complete Fontan pathway restriction, PediMag reduced inferior vena cava pressure by ∼10 mm Hg and supported CO augmentation up to 5 L/min. This was accompanied by an increase in superior vena cava pressure of ∼6 mm Hg. CentriMag produced similar hemodynamic changes without the need for pathway restriction or an increase in superior vena cava pressure. CONCLUSIONS: PediMag and CentriMag right-sided support led to a decrease in inferior vena cava pressure and augmentation of cardiac output. In the case of CentriMag, this is accomplished without an increase in superior vena cava pressure or the need for restrictive banding. This work provides further data to help with the optimal design of a Fontan assist device to ameliorate the growing need.

Impact of hemodynamics and fluid energetics on liver fibrosis after Fontan operation.

OBJECTIVE: The staged Fontan procedure has shown promising short-term outcomes in patients with single ventricles. However, Fontan-associated liver disease is a marked problem as patients age. The purpose of this study is to investigate the relationship between hemodynamics and liver fibrosis in patients undergoing the Fontan. METHODS: A total of 33 patients undergoing the Fontan with liver fibrosis were included in this study. Cardiac magnetic resonance and phase-contrast cardiac magnetic resonance data, as well as catheterization measurements and liver biopsies, were obtained for each patient. Computational fluid dynamic simulations were performed to quantify total cavopulmonary connection hemodynamics using patient-specific anatomies and blood flow waveforms reconstructed from cardiac magnetic resonance data. Collagen deposition (as a measure of liver fibrosis) was quantified by digital image analysis of Sirius Red stained slides. Statistical analyses were performed to investigate potential relationships between liver fibrosis and Fontan hemodynamics. RESULTS: Liver fibrosis was found to be related to global metrics (inferior vena cava flow, ventricle power output) rather than to local total cavopulmonary connection hemodynamics and efficiency. Indexed inferior vena cava flow showed a significant, positive correlation with liver fibrosis (rho = 0.624, P < .001). Upper and lower Sirius Red tertile comparisons showed a significant difference in indexed inferior vena cava flow (P = .008). CONCLUSIONS: Significant increases in inferior vena cava flow consistent with fibrosis induced arterialization and ventricular power output suggest a burden being placed on the single ventricle from liver fibrosis. Local total cavopulmonary connection flow dynamics do not seem to influence the degree of fibrosis. Favorable total cavopulmonary connection hemodynamics may not be enough to overcome the power shortage and elevated venous pressures inherent to a Fontan circulation.

Fontan Surgical Planning: Previous Accomplishments, Current Challenges, and Future Directions.

The ultimate goal of Fontan surgical planning is to provide additional insights into the clinical decision-making process. In its current state, surgical planning offers an accurate hemodynamic assessment of the pre-operative condition, provides anatomical constraints for potential surgical options, and produces decent post-operative predictions if boundary conditions are similar enough between the pre-operative and post-operative states. Moving forward, validation with post-operative data is a necessary step in order to assess the accuracy of surgical planning and determine which methodological improvements are needed. Future efforts to automate the surgical planning process will reduce the individual expertise needed and encourage use in the clinic by clinicians. As post-operative physiologic predictions improve, Fontan surgical planning will become an more effective tool to accurately model patient-specific hemodynamics.

A pulsatile hemodynamic evaluation of the commercially available bifurcated Y-graft Fontan modification and comparison with the lateral tunnel and extracardiac conduits.

OBJECTIVE: Fontan completion, resulting in a total cavopulmonary connection, is accomplished using a lateral tunnel, extracardiac conduit, or bifurcated Y-graft. The use of Y-grafts is hypothesized to provide symmetric hepatic blood flow distribution to the lungs, a factor related to pulmonary arteriovenous malformations. The present study evaluates the hemodynamic performance of the largest commercially available Y-graft cohort to date, highlights 6 representative cases, and compares commercially available Y-graft performance with lateral tunnel/extracardiac conduit connections. METHODS: A total of 30 patients with commercially available Y-grafts and 30 patients with lateral tunnel/extracardiac conduits were analyzed. Total cavopulmonary connection anatomies and flow waveforms were reconstructed using cardiac magnetic resonance images and phase-contrast cardiac magnetic resonance. Computational fluid dynamic simulations were performed to quantify total cavopulmonary connection power loss, resistance, and hepatic flow distribution. Comparisons between graft types were investigated. RESULTS: Total cavopulmonary connection resistance was significantly higher for Y-grafts. Hepatic flow distribution was similar overall but showed discrepancies at extreme values with more unbalanced flow in the Y-graft cohort. Power loss was more sensitive to left pulmonary artery stenosis in the Y-graft cohort. Prediction of Y-graft hepatic flow distribution is multifactorial. CONCLUSIONS: Commercially available Y-grafts do not inherently provide more balanced hepatic flow distribution than lateral tunnel/extracardiac conduit connections, which are more energetically favorable and less sensitive to pulmonary artery stenosis. Graft type should be considered on an individual basis because hemodynamic performance is based on a combination of factors, including pulmonary flow distribution, pulmonary artery stenosis, and superior vena cava positioning.