Cava Flow Research Articles

Innovative balloon-inflatable venous cannula for enhanced cardiopulmonary bypass in minimally invasive cardiac surgery.

Minimally invasive cardiac surgery (MICS) struggles with effective caval isolation and cannulation for cardiopulmonary bypass (CPB). We aimed to develop a novel MICS venous cannula, eliminating external manipulations. The goal of this study is to thoroughly evaluate both the safety and the efficacy of a newly developed venous cannula. The study presents the Aulus venous cannula for MICS, designed with internal balloons to block caval blood flow. Preclinical bench tests with a cardiac biosimulator and large animal studies per ISO10993-2016, evaluated performance and safety. The heparin-coated Aulus cannula had a post-sterilization comparable density of ∼0.200 μg/cm2. In ex vivo tests, using porcine heart models, the cannula enabled full caval occlusion, with endoscopic views confirming precise positioning. The pressure drop remained below the hemolytic threshold of 100 mmHg, indicated lower values compared to BioMedicus. A non-GLP large animal study included eight ovine models, divided into short- and long-term follow-up groups. Clinical pathology values were consistent CPB procedures, and histopathology indicated favourable tolerance despite short-term vessel injuries and long-term stenosis with fibrosis. The Aulus cannula showed effective anticoagulant activity, strong integrity, and good tolerance in vitro and in vivo, highlighting its clinical potential.

Abstract 4131412: Effects of Angiotensin Converting Enzyme Inhibition And Afterload Reduction in Single Ventricle Patients Prior To Fontan: Not What You Might Think

Introduction: Pts with single ventricle (SV) after bidirectional Glenn (BDG) are placed on angiotensin converting enzyme inhibitors (ACEI) to reduce afterload, improve ventricular performance and allow for decreased systemic to pulmonary collateral flow (APC). No large scale data exists to support ACEI use in BDG pts to accomplish this. We hypothesized that ACEI may not perform as predicted. Goals: To determine if ACEI use in BDG pts decreases APC and improves ventricular function. Methods: Single center retrospective study of all BDG pts who underwent cardiac magnetic resonance (CMR) from 2010 to present. Demographics, medication, ventricular function and flow data were collected. Pts included were >1 year old and on ACEI for >3 months prior to CMR. Wilcoxon and Fisher Exact tests were used. Significance P<0.05 Results: Of the 320 BDG pts (median 2.8 years old) studied, 137 (43%) were treated with ACEI. See table for all data. There was no difference in age, sex, medications (except for ACEI) or body surface area (BSA) between both groups. APC as a % of aortic flow and APC/BSA were not different between those treated with ACEI compared to those who were not, whether right (RV) or left ventricle (LV) dominant. There was no correlation of APC with time on ACEI or ACEI dosage. Ejection fraction (EF) was lower and end-diastolic volume (EDV) was higher in BDG on ACEI for the entire group and RVs. Although LV EDV was higher with those on ACEI, LV EF was the same for those on ACEI and those who weren’t (graph). APC as a % of aortic flow and APC/BSA positively correlated with EDV (rho 0.25-0.34, P<.001). There was no difference in atrioventricular valve regurgitation between those on ACEI and those who were not (median 5 vs 6% respectively). As a surrogate for cerebral blood flow (CBF), superior vena caval (SVC) flow was lower for those on ACEI compared to those who were not. Conclusion: BDG pts treated with ACEI did not demonstrate decreased APC or improved ventricular performance. There is a suggestion that ventricular performance may be worse on ACEI. CBF is decreased in BDG on ACEI using SVC flow as a surrogate. This suggests that ACEI use in SV pts at the BDG stage is not indicated and should be discouraged.

Active Machine Learning for Pre-procedural Prediction of Time-Varying Boundary Condition After Fontan Procedure Using Generative Adversarial Networks.

The Fontan procedure is the definitive palliation for pediatric patients born with single ventricles. Surgical planning for the Fontan procedure has emerged as a promising vehicle toward optimizing outcomes, where pre-operative measurements are used prospectively as post-operative boundary conditions for simulation. Nevertheless, actual post-operative measurements can be very different from pre-operative states, which raises questions for the accuracy of surgical planning. The goal of this study is to apply machine leaning techniques to describing pre-operative and post-operative vena caval flow conditions in Fontan patients in order to develop predictions of post-operative boundary conditions to be used in surgical planning. Based on a virtual cohort synthesized by lumped-parameter models, we proposed a novel diversity-aware generative adversarial active learning framework to successfully train predictive deep neural networks on very limited amount of cases that are generally faced by cardiovascular studies. Results of 14 groups of experiments uniquely combining different data query strategies, metrics, and data augmentation options with generative adversarial networks demonstrated that the highest overall prediction accuracy and coefficient of determination were exhibited by the proposed method. This framework serves as a first step toward deep learning for cardiovascular flow prediction/regression with reduced labeling requirements and augmented learning space.

Complex Hepatectomy Under Total Vascular Exclusion of the Liver Preserving the Caval Flow with Portal Hypothermic Perfusion and Temporary Portacaval Shunt: A Proof of Concept.

Hypothermic liver perfusion decreases ischemia/reperfusion injury during hepatectomy under standard total vascular exclusion (TVE) of the liver. This surgery needs venovenous bypass and is hampered by high morbi-mortality. TVE preserving the inferior vena cava (IVC) flow is hemodynamically well tolerated but remains limited in duration when performed under liver normothermia. The objective of this study was to report the results of TVE preserving the caval flow, modified to allow hypothermic liver perfusion and obviate splanchnic congestion. The technique, indicated for tumors abutting large tributaries of the hepatic veins but sparing their roots in IVC and the latter, was applied when TVE was anticipated to last for ≥ 60 min. It combines continuous TVE preserving the IVC flow with hypothermic liver perfusion and temporary portacaval shunt (PCS). Results are given as median (range). Vascular control was achieved in 13 patients with excellent hemodynamical tolerance. PCS was direct or via an interposed synthetic graft (five and eight cases, respectively). Liver temperature dropped to 16.5 (6-24) °C under perfusion of 2 (2-4) L of cold perfusate. TVE lasted 67 (54-125) min and 4.5 (0-8) blood units were transfused. Resection was major in nine cases and was complete in all cases. Five complications occurred in four patients, and the 90-day mortality rate was zero. This technique maintains stable hemodynamics and combines the advantages of in situ or ex situ standard TVE with hypothermic liver perfusion, without their inherent prolongation of ischemia time and need for venovenous bypass.

Impact of Age-Related Change in Caval Flow Ratio on Hepatic Flow Distribution in the Fontan Circulation.

The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac conduit or a lateral tunnel connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. The effect of age-related changes in caval inflows on HFD was evaluated using cardiac magnetic resonance data and patient-specific computational fluid dynamics modeling. SVC and IVC flow from 414 patients with Fontan were collected to establish a relationship between SVC:IVC flow ratio and age. Computational fluid dynamics modeling was performed in 60 (30 extracardiac and 30 lateral tunnel) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively. SVC:IVC flow ratio inverted at ≈8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC, 2, 1, and 0.5 corresponded to ages, 3, 8, and 15+, respectively) was not significant for extracardiac but statistically significant for lateral tunnel cohorts. For all 3 caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2 to 0.5 (age, 3-15+) years, the correlation's strength decreased from 0.87 to 0.64, due to potential flow perturbation as IVC flow momentum increased. Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of SVC:IVC variations over time on Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.

Respiratory-resolved five-dimensional flow cardiovascular magnetic resonance : In-vivo validation and respiratory-dependent flow changes in healthy volunteers and patients with congenital heart disease

BackgroundThis study aimed to validate respiratory-resolved 5D flow MRI against real-time 2D phase contrast MRI, assess the impact of number of respiratory states, and measure the impact of respiration on hemodynamics in congenital heart disease (CHD) patients. MethodsRespiratory-resolved 5D flow MRI derived net and peak flow measurements were compared to real-time 2D phase contrast MRI derived measurements in 10 healthy volunteers. Pulmonary to systemic flow ratios (Qp:Qs) were measured in 19 CHD patients and aortopulmonary collateral burden was measured in 5 Fontan patients. Additionally, the impact of number of respiratory states on measured respiratory-driven net flow changes was investigated in 10 healthy volunteers and 19 CHD patients (shunt physiology, n=11, single ventricle disease (SVD), n=8). ResultsThere was good agreement between 5D flow MRI and real-time 2D phase contrast derived net and peak flow. Respiratory driven changes had good correlation (rho=0.64, p<0.001). In healthy volunteers, fewer than four respiratory states reduced measured respiratory driven flow changes in veins (5.2mL/cycle, p<0.001) and arteries (1.7mL/cycle, p=0.05). Respiration drove substantial venous net flow changes in SVD (64% change) and shunt patients (57% change). Respiration had significantly greater impact in SVD patients compared to shunt patients in the right and left pulmonary arteries (46% vs 15%, p=0.003 & 59% vs 20%, p=0.002). Qp:Qs varied by 37±24% over respiration in SVD patients and 12±20% in shunt patients. Aortopulmonary collateral burden varied by 118±84% over respiration in Fontan patients. The smallest collateral burden was measured during active inspiration in all patients and the greatest burden was during active expiration in 4 of 5 patients. Reduced respiratory resolution blunted measured flow changes in the caval veins of shunt and SVD patients (p<0.005). ConclusionsRespiratory-resolved 5D flow MRI measurements agree with real-time 2D phase contrast. Venous measurements are sensitive to number of respiratory states, whereas arterial measurements are more robust. Respiration has substantial impact on caval vein flow, Qp:Qs, and collateral burden in CHD patients.

Intraoperative transit-time flow measurement of caval veins before and after bidirectional cavopulmonary anastomosis.

Haemodynamic changes in caval venous flow distribution occurring during bidirectional cavopulmonary anastomosis operation are still largely unknown. Transit time flow measurements were performed in 15 cavopulmonary anastomosis operations. Superior and inferior caval vein flows were measured before and after the cavopulmonary anastomosis. Ratio of superior caval vein to overall caval veins flow was calculated. Mean superior caval vein flow ratio before cavopulmonary anastomosis was higher than previously reported for healthy children. Superior caval vein flow ratio decreased in 14/15 patients after cavopulmonary anastomosis: mean 0.63 ± 0.12 before versus 0.43 ± 0.14 after. No linear correlation between intraoperative superior caval vein pressure and superior caval vein flow after cavopulmonary anastomosis was found. Neither Nakata index nor pulmonary vascular resistance measured at preoperative cardiac catheterisation correlated with intraoperative flows. None of patients died or required a take down. The higher mean superior caval vein flow ratio before cavopulmonary anastomosis compared to healthy children suggests flow redistribution in univentricular physiology to protect brain and neurodevelopment. The decrease of superior caval vein flow ratio after cavopulmonary anastomosis may reflect the flow redistribution related to trans-pulmonary gradient. The lack of correlation between superior caval vein pressure and superior caval vein flow could be explained by limited sample size and multifactorial determinants of caval veins flow, although pressure remain essential. Larger sample of measurements are needed to find flow range potentially predictive for clinical failure. To authors' knowledge, this is the first intraoperative flow measurement of both caval veins during cavopulmonary operations.

Feasibility of an Animal Model for Cavopulmonary Support With a Double-Outflow Pump.

Both single- and double-outflow cavopulmonary assist devices (CPADs) were recently proposed for the Fontan population, whereas single-outflow configurations were evaluated in large animal trials and double-outflow concepts are lacking an equivalent in vivo assessment. The aim of this study was to test the hemodynamic properties of a double-outflow CPAD device in an acute sheep model. The two inflow cannulae of a CPAD were anastomosed to the caval veins. Outflow graft connection was performed via end-to-side anastomosis to the right (RPA) and main pulmonary artery (MPA). Speed ramp protocols were conducted, and hemodynamic effects were monitored in terms of caval flows, cardiac output (CO), central venous pressure (CVP), pulmonary artery pressure (PAP), and left atrial pressure (LAP). Six experiments were conducted (53.35 ± 5.1 kg). In three experiments, the animal model was established, the CPAD was examined, and restoration of biventricular equivalency in terms of venous return was achieved. Venous pressures (CVP) declined linearly with increasing pump speed (r > 0.879), whereas caval flow (r > 0.973), CO (r > 0.993), PAP (r > 0.973), and LAP (r > 0.408) increased. Despite the considerable complexity of the sheep model caused by the sheep pulmonary arterial anatomy that requires substantial graft bending, the CPAD was evaluated in three acute experiments and showed the potential to completely substitute a subpulmonary ventricle.

Percutaneous Transluminal Caval-Flow Regulation PTCR®: A New Alternative Therapy to Reshape the Future Treatment of Heart Failure

Percutaneous Transluminal Caval-flow Regulation (PTCR) is an emerging alternative therapy to treat patients with acute heart failure (AHF). AHF represents the first cause of hospitalization in elderly persons and is the main determinant of the huge healthcare expenditure related to heart failure (HF). Despite therapeutic advances, the prognosis of AHF is poor, with in-hospital mortality ranging from 4% to 7%, 60 to 90-day mortality. To reverse this situation, a balloon catheter medical device has been designed to produce cyclic occlusions of the Inferior Vena Cava (IVC) supported by the phases of respiration, thus having subtotal occlusion during expiration and total occlusion during inspiration, producing an intermittent regulation of venous return or preload from the IVC to the right atrium. This PTCR procedure is minimally invasive. It is performed through the insertion of the balloon catheter via the femoral vein. This catheter is advanced to the IVC guided by echocardiogram or fluoroscopy to be placed prior to drainage of the hepatic vein. At this point, the balloon is inflated up to 70% to 80% of the diameter of the IVC in expiration, which has to be previously evaluated by echocardiography. Then inspiratory collapse (20 to 30% average) of the IVC diameter produces total occlusion during inspiration and a partial or subtotal occlusion during expiration, thereby regulating caval flow in an intermittent manner. This innovative procedure is aimed at regulating the hypervolemia present in the IVC, normalizing venous return, preload, intracardiac pressures, biventricular diastolic and systolic diameters, diastolic and systolic volume, thus, obtaining reduction of total cardiac burden (TCB) and producing a reversal of ventricular remodeling. In this manner the heart returns close to its original design, with improvement in ejection fraction (EF) and cardiac output.

Abstract 13627: Hepatic Venous Return to Lungs in Fontan is Dependent on Age-Dependent Caval Flow Ratio

Introduction: The Fontan procedure is performed between 2-4 years of age and is a palliative technique for patients born with single ventricle defects. The Fontan physiology is the result of a total cavopulmonary connection between superior and inferior vena cava (SVC and IVC) and the hepatic veins to the pulmonary arteries (PA). Maldistribution of hepatic blood flow to the lungs can result in the formation of pulmonary arteriovenous malformations (PAVM) and resulting cyanosis. Hepatic blood flow distribution (HFD) to right and left lungs is highly dependent on the local flow dynamics. We sought to investigate the impact of SVC-to-IVC flow ratio and age on HFD. Methods: SVC and IVC flow data measured by cardiac MRI (CMR) from 81 Fontan patients were collected to establish the relationship between SVC: IVC flow ratio vs. age. 3D Patient-specific computational fluid dynamics (CFD) modeling was performed for 5 patients who underwent Fontan procedure with an extracardiac conduit to quantify the HFD to the right and left PAs. We evaluated the dependency of HFD on SVC: IVC flow ratio by quantifying HFD to different SVC: IVC flow ratios (2, 1.0, and 0.5) for a given Fontan anatomy. Results: SVC: IVC flow ratio inverted at ~10 years of age (n=81, Figure A) indicating a clear shift to lower body predominance in overall caval flow. CFD analysis (n=5) showed that the shift in SVC-IVC flow had a significant effect on the HFD (Fig. B-F). Change in HFD was more substantial as SVC: IVC flow ratio shifted from 2 to 1 [~5-10 years] with an average % change of 21±6 compared to the HFD change that occurred for a shift of 1 to 0.5 [9±11 for ~10-20 years] (Fig. B-F). Conclusion: Well-balanced distribution of HFD is essential to prevent PAVMs and to ensure long-term efficacy of a Fontan. This study highlights how SVC: IVC flow ratios change over time and can impact HFD to PAs. Interventions to address HFD maldistribution should not be considered in isolation and should incorporate predictions of SVC: IVC changes over time.

Longitudinal Trends of Vascular Flow and Growth in Patients Undergoing Fontan Operation

BackgroundSingle ventricle (SV) patients undergo multiple surgeries with subsequent changes in anatomy and hemodynamics. There are little cardiac magnetic resonance (CMR) data on serial changes in these patients. This study aimed to assess longitudinal changes of SV anatomy and hemodynamics in a large cohort. MethodsAnatomy and flow in SV patients with serial CMRs performed between 2008 and 2019 at a single institution were retrospectively reviewed. Mixed-effects linear regression was used to estimate changes over time at 3 to 9 months, 1 to 5 years, and >5 years after Fontan. ResultsA total of 119 patients were included (51% with hypoplastic left heart syndrome; 77% underwent extracardiac Fontan). A total of 88 patients had 3 serial CMRs. Indexed right superior vena cava, inferior vena cava, neoaortic valve, and descending aorta area decreased over time (beta = -0.19, -0.44, and -0.23, respectively; P < .01), as did indexed right superior vena cava, neoaorta and native aorta, and descending aorta flow (beta = -0.49, -0.53, and -0.59, respectively; P < .0001). Inferior vena cava flow and its contribution to total caval flow increased (beta = 0.33; P < .0001). Indexed right and left pulmonary artery flow did not change; however, indexed left pulmonary artery area decreased (beta = -0.16; P = .0014) with time. Systemic-to-pulmonary collateral flow remained unchanged before and early after Fontan (beta = -0.54; P = .42) but decreased with time from Fontan (beta = -0.22; P < .0001). ConclusionsIn this cohort of longitudinally followed SV patients, there are significant trends in vascular size and flow over time from Fontan. These findings can be used as a framework to interpret serial CMR data in the SV and noninvasively identify deviations from expected patterns before the development of clinical symptoms.

Hemodynamic effects of pulmonary regurgitation in one and one-half ventricle repair.

The pulmonary circulation after one and one-half ventricle repair is complex because of the direct connection of two sources of blood flow. Associated pulmonary regurgitation further complicates the pulmonary circulation. We report the complex hemodynamics depicted by phase-contrast magnetic resonance imaging in a patient with one and one-half ventricle circuit and severe pulmonary regurgitation. Antegrade superior vena caval flow occurred almost exclusively during diastole and regurgitated into the right ventricle. Consequently, the entire systemic venous return reached the right ventricle during diastole and is pumped back into the pulmonary arteries in systole. The case highlights the importance of analyzing flow patternsphase-by phase throughout the cardiac cycle instead of relying on the net flow volumes through each source of pulmonary blood flow.

Hemodynamic parameters after Delayed Cord Clamping (DCC) in term neonates: a prospective observational study.

BackgroundDelayed cord clamping (DCC) is practiced worldwide, as standard care in both term and preterm babies. Our aim was to determine the hemodynamic effects of DCC on transitional circulation.Material and methodsThis prospective observational study was carried out in a tertiary care hospital, at Pune, India, from May 2018 to October 2019.Term neonates born during the study period were included. The primary outcome variables of the study were right ventricular output (RVO), left ventricular output (LVO), superior vena cava (SVC) flow (ml/kg/min) and heart rate(HR) at 12 ± 6 and 48 ± 6 h of life measured by point of care functional echocardiography. Inter-observer and intra-observer variability was calculated for these parameters.ResultsOut of a total of 2744 deliveries during the study period, 620 babies were included. Mean gestational age of the enrolled babies was 38.96 ± 1.08 weeks and mean birth weight was 2.9 ± 0.39 kg. Mean heart rate of babies recorded at 12 ± 6 h of life was 127 beats per minute (bpm) whereas it was 128 bpm at 48 ± 6 h of life. RVO {mean (SD)} was 209.55(44.89) and 205.85(46.35) ml/kg/min, LVO {mean (SD)} was 133.68(31.15) and 134.78(29.84) ml/kg/min whereas SVC flow {mean (SD)} was 106.85(26.21) and 109.29(25.11) ml/kg/min at 12 ± 6 and 48 ± 6 h of life respectively. There was good intra-observer agreement in all the variables.SGA babies had a significantly higher heart rate at 12 ± 6 h of life as compared to AGA babies, although this difference in heart rate could not be appreciated at 48 ± 6 h of life. However SGA babies had a higher LVO, RVO and SVC flow than AGA babies at both the time points of observation.ConclusionAfter DCC there is less fluctuation in the hemodynamic parameters (heart rate, cardiac output) at the two time points of observation.. As compared to AGA babies, SGA babies had a significantly higher baseline heart rate, LVO, RVO and SVC flow. LVO of SGA babies after delayed cord clamping is found to be significantly lower than LVO seen in other studies, favoring the cardio-stabilizing effect of DCC.Brief rationaleThis is the first study with a large sample size evaluating the hemodynamic effects of DCC in term neonates by functional echocardiography. The normative data of heart rate and cardiac output of term, stable babies with small for gestational age(SGA) as a special subgroup undergoing DCC requires further evaluation.

Novel devices for managing heart failure.

Despite advances in heart failure (HF) therapies, the associated morbidity, mortality, hospitalization rates, and healthcare expenditures remain high. A significant proportion of patients with HF remain symptomatic despite receiving optimal medical therapy. Consequently, there exists a large unmet clinical need for novel therapies for treating acute and chronic HF. With the exponential growth of transcatheter interventions in structural heart disease, novel applications of minimally invasive, device-based therapies have been sought in an effort to bridge this treatment gap. The rationale, development, and current data underscoring these therapies will be summarized in this review. Recent studies have demonstrated the safety and efficacy of devices that alter left ventricular geometry (i.e., ventriculoplasty), create anatomic shunts to decompress the left atrium, and modulate vena caval and renal blood flow. However pivotal large trials evaluating clinical outcomes are ongoing. Innovative device-based therapies may expand our armamentarium against the growing heterogeneous and morbid HF syndrome.

First-in-human experience of preload regulation with percutaneous transluminal caval flow regulation in heart failure with reduced ejection fraction patients.

AimsThis study aims to investigate the acute haemodynamic effects of percutaneous transluminal flow regulation (PTCR®) with an inferior vena cava regulator balloon in heart failure patients. Preload reduction in heart failure has been achieved with high potency diuretics. However, no study has been conducted in humans to assess the effect of inferior vena cava intermittent occlusion for preload reduction.Methods and resultsSix patients were included in the study: four men (55 ± 6 years old) and two women (63 ± 4 years old). Baseline evaluations included Doppler echocardiogram, coronary angiogram, and right heart catheterization. Caval balloon was kept inflated for 30 min, and right catheterization and control echocardiogram were performed while the balloon was still inflated. The balloon was then deflated and removed. Right haemodynamic variables were evaluated before balloon insertion and with the inflated balloon. The mean right atrial pressure decreased by 42.59% (P = 0.005); systolic right ventricular pressure decreased by 30.19% (P < 0.003); mean pulmonary arterial pressure decreased by 25.33% (P < 0.043); mean pulmonary capillary wedge pressure decreased by 31.37% (P > 0.016); and cardiac output increased by 9.92% (P < 0.175).ConclusionsThe haemodynamic and echocardiographic changes obtained in our study using PTCR® suggest that this innovative approach can play a beneficial role in the heart failure treatment.

Role of cardiac MRI in the prediction of pre-Fontan end-diastolic ventricular pressure.

Growing evidence has emphasised the importance of ventricular performance in functionally single-ventricle patients, particularly concerning diastolic function. Cardiac MRI has been proposed as non-invasive alternative to pre-Fontan cardiac catheterisation in selected patients. To identify clinical and cardiac magnetic resonance predictors of high pre-Fontan end-diastolic ventricular pressure. In a retrospective single-centre study, 38 patients with functionally univentricular heart candidate for Fontan intervention, who underwent pre-Fontan cardiac catheterisation, beside a comprehensive cardiac MRI, echocardiographic, and clinical assessment were included. Medical and surgical history, cardiac magnetic resonance, cardiac catheterisation, echocardiographic, and clinical data were recorded. We investigated the association between non-invasive parameters and cardiac catheterisation pre-Fontan risk factors, in particular with end-diastolic ventricular pressure. Moreover, the impact of conventional invasive pre-Fontan risk factor on post-operative outcome as also assessed. Post-operative complications were associated with higher end-diastolic ventricular pressure and Mayo Clinic indexes (p < 0.01 and p = 0.05, respectively). At receiver operating characteristic curve analysis end-diastolic ventricular pressure ≥ 10.5 mmHg predicted post-operative complications with a sensitivity of 75% and specificity of 88% (AUC: 0.795, 95% CI 0.576;1.000, p < 0.05). At multivariate analysis, both systemic right ventricle (OR: 23.312, 95% CI: 2.704-200.979, p < 0.01) and superior caval vein indexed flow (OR: 0.996, 95% CI: 0.993-0.999, p < 0.05) influenced end-diastolic ventricular pressure ≥ 10.5 mmHg. A reduced superior caval vein flow, evaluated at cardiac magnetic resonance, is associated with higher end-diastolic ventricular pressure a predictor of early adverse outcome in post-Fontan patients.

Persistent Right Venous Valve: Insights From Multimodality Imaging.

Anatomic variants in the right atrium are under-recognized and under-reported phenomena in cardiac imaging. In the fetus, right atrium serves as a conduit for oxygenated blood to be delivered to the left heart bypassing the right ventricle and the nonfunctional lungs. The anatomy in the fetal right atrium is designed for such purposeful circulation. The right and left venous valves are prominent structures in the fetal heart that direct inferior vena caval flow towards the foramen ovale. These anatomic structures typically regress and the foramen ovale closes after birth. However, the venous valves can persist leading to a range of anatomic, physiological, and pathological consequences in the adult. We describe various presentations of persistent venous valves, focusing on the right venous valve in this illustrated multimodality imaging article.

Impact of bilateral bidirectional Glenn anastomosis on staged Fontan strategy and Fontan circulation.

The aim of this study was to identify the impact of bilateral bidirectional Glenn (BBDG) anastomosis on staged Fontan strategy and late Fontan circulation. Of 267 patients who underwent bidirectional Glenn prior to Fontan completion between 1989 and 2013, 62 patients (23%) who underwent BBDG were enrolled in this study. Age at operation was 0.84 years (25th-75th percentile: 0.58-1.39). Thirty-three patients had heterotaxy syndrome (53%). The mean follow-up period was 12.7 ± 8.1 (max. 30.6) years. The overall survival rate at 15 years was 73%. Although 49 patients (79.0%) went on to Fontan completion, 12 patients (19.4%) died without achieving it. Thrombus formation and poor development in a central pulmonary artery were not observed, but obstruction of the superior vena cava (SVC) occurred in 8 patients (13%), mainly those with right atrial isomerism (P = 0.037). SVC obstruction was not, however, a risk factor for mortality (P = 0.097) or Fontan completion (P = 0.41). The shape of BBDG anastomosis, symmetricity of pulmonary blood flow, impingement of caval blood flow returning from the superior and inferior vena cavae or coexisting interrupted inferior vena cava with azygos or hemi-azygos continuation did not affect late Fontan outcomes, such as overall survival, freedom from protein-losing enteropathy or pulmonary arterio-venous malformation rates. SVC obstruction after BBDG frequently occurred, mainly in patients with right atrial isomerism; however, its direct impact on prognosis or achieving Fontan completion was not identified. Once Fontan circulation was established, the arrangement of the Fontan pathway did not affect late Fontan outcomes.

Non-uniform mixing of hepatic venous flow and inferior vena cava flow in the Fontan conduit.

Fontan patients require a balanced hepatic blood flow distribution (HFD) to prevent pulmonary arteriovenous malformations. Currently, HFD is quantified by tracking Fontan conduit flow, assuming hepatic venous (HV) flow to be uniformly distributed within the Fontan conduit. However, this assumption may be unvalid leading to inaccuracies in HFD quantification with potential clinical impact. The aim of this study was to (i) assess the mixing of HV flow and inferior vena caval (IVC) flow within the Fontan conduit and (ii) quantify HFD by directly tracking HV flow and quantitatively comparing results with the conventional approach. Patient-specific, time-resolved computational fluid dynamic models of 15 total cavopulmonary connections were generated, including the HV and subhepatic IVC. Mixing of HV and IVC flow, on a scale between 0 (no mixing) and 1 (perfect mixing), was assessed at the caudal and cranial Fontan conduit. HFD was quantified by tracking particles from the caudal (HFDcaudal conduit) and cranial (HFDcranial conduit) conduit and from the hepatic veins (HFDHV). HV flow was non-uniformly distributed at both the caudal (mean mixing 0.66 ± 0.13) and cranial (mean 0.79 ± 0.11) level within the Fontan conduit. On a cohort level, differences in HFD between methods were significant but small; HFDHV (51.0 ± 20.6%) versus HFDcaudal conduit (48.2 ± 21.9%, p = 0.033) or HFDcranial conduit (48.0 ± 21.9%, p = 0.044). However, individual absolute differences of 8.2–14.9% in HFD were observed in 4/15 patients. HV flow is non-uniformly distributed within the Fontan conduit. Substantial individual inaccuracies in HFD quantification were observed in a subset of patients with potential clinical impact.

FACTORS OF PERIOPERATIVE MORTALITY IN PATIENTS WITH GROWING RENAL CELL CARCINOMA IN INFERIOR VENA CAVA LUMEN

Difficult surgical cases of tumors of the inferior vena cava occur very often, because this intervention is characterized with technical difficulties and severe intraoperative complications. The most dangerous of these include massive bleeding, acute heart failure, and pulmonary embolism by tumor masses, which are the most common causes of perioperative mortality. Vena cava trombectomy is a special operation that can be accompanied by heavy bleeding at virtually any stage. The causes and frequency of mortality in 108 patients operated for renal cell carcinoma with growing to the inferior vena cava were retrospectively analyzed. Reliable factors for the prognosis of perioperative mortality in this pathology have been identified. Factors that characterize the tumor thrombus features, as well as parameters related to general condition of a patient, have been found to be of the greatest importance. The results of the study showed that the level of perioperative mortality in caval tumor thrombi is 8.3 % when using surgical methods without artificial circulation. The presented patient population contained a significant proportion of so−called "high" thrombi of III−IV levels, thrombi invading the wall of the inferior vena cava, as well as retrograde spread of intraluminal tumor. The main causes of death were acute heart failure, intraoperative bleeding, pulmonary embolism with tumor masses and acute renal failure. The prognostic value of perioperative mortality was demonstrated by the following thrombus factors: its "high" level, invasion of intraluminal tumor into the caval wall, signs of complete obstruction of caval blood flow. The mortality rate was objectively affected by severe heart failure, signs of pulmonary embolism before surgery. Key words: inferior vena cava, tumor thrombus, renal cell carcinoma, vena cava trombectomy, lethality.