Head-to-Head Comparison of Hepatic Vein and Superior Vena Cava Flow Velocity Waveform Analyses for Predicting Elevated Right Atrial Pressure.

OBJECTIVE: Blood flow in the hepatic veins and superior vena cava (SVC) reflects right heart filling; however, their Doppler profiles are often not identical, and no studies have compared their diagnostic efficacies. We aimed to determine which venous Doppler profile is reliable for detecting elevated right atrial pressure (RAP). METHODS: In 193 patients with cardiovascular diseases who underwent cardiac catheterization within 2 d of echocardiography, the hepatic vein systolic filling fraction (HV-SFF) and the ratio of the peak systolic to diastolic forward velocities of the SVC (SVC-S/D) were measured. HV-SFF < 55% and SVC-S/D < 1.9 were regarded as elevated RAP. We also calculated the fibrosis 4 index (FIB-4) as a serum liver fibrosis marker. RESULTS: HV-SFF and SVC-S/D were feasible in 177 (92%) and 173 (90%) patients, respectively. In the 161 patients in whom both venous Doppler waveforms could be measured, HV-SFF and SVC-S/D were inversely correlated with RAP (r = -0.350, p < 0.001; r = -0.430, p < 0.001, respectively). SVC-S/D > 1.9 showed a significantly higher diagnostic accuracy of RAP elevation compared with HV-SFF < 55% (area under the curve, 0.842 vs. 0.614, p < 0.001). Multivariate analyses showed that both FIB-4 (ß = -0.211, p = 0.013) and mean RAP (ß = -0.319, p < 0.001) were independent determinants of HV-SFF. In contrast, not FIB-4 but mean RAP (ß = -0.471, p < 0.001) was an independent determinant of SVC-S/D. The diagnostic accuracy remained unchanged when HV-SFF < 55% was considered in conjunction with the estimated RAP based on the inferior vena cava morphology. Conversely, SVC-S/D showed an incremental diagnostic value over the estimated RAP. CONCLUSIONS: SVC-S/D enabled a more accurate diagnosis of RAP elevation than HV-SFF.

Biomechanical Analysis of Age-Dependent Changes in Fontan Power Loss.

The hemodynamics in Fontan patients with single ventricles rely on favorable flow and energetics, especially in the absence of a subpulmonary ventricle. Age-related changes in energetics for extracardiac and lateral tunnel Fontan procedures are not well understood. Vorticity (VOR) and viscous dissipation rate (VDR) are two descriptors that can provide insights into flow dynamics and dissipative areas in Fontan pathways, potentially contributing to power loss. This study examined power loss and its correlation with spatio-temporal flow descriptors (vorticity and VDR). Data from 414 Fontan patients were used to establish a relationship between the superior vena cava (SVC) to inferior vena cava (IVC) flow ratio and age. Computational flow modeling was conducted for both extracardiac conduits (ECC, n = 16) and lateral tunnels (LT, n = 25) at different caval inflow ratios of 2, 1, and 0.5 that corresponded with ages 3, 8, and 15+. In both cohorts, vorticity and VDR correlated well with PL, but ECC cohort exhibited a slightly stronger correlation for PL-VOR (>0.83) and PL-VDR (>0.89) than that for LT cohort (>0.76 and > 0.77, respectively) at all ages. Our data also suggested that absolute and indexed PL increase (p < 0.02) non-linearly as caval inflow changes with age and are highly patient-specific. Comparison of indexed power loss between our ECC and LT cohort showed that while ECC had a slightly higher median PL for all 3 caval inflow ratio examined (3.3, 8.3, 15.3) as opposed to (2.7, 7.6, 14.8), these differences were statistically non-significant. Lastly, there was a consistent rise in pressure gradient across the TCPC with age-related increase in IVC flows for both ECC and LT Fontan patient cohort. Our study provided hemodynamic insights into Fontan energetics and how they are impacted by age-dependent change in caval inflow. This workflow may help assess the long-term sustainability of the Fontan circulation and inform the design of more efficient Fontan conduits.

Intracranial Pressure and Cerebral Hemodynamics in Infants Before and After Glenn Procedure.

OBJECTIVES: This prospective cohort study aimed to investigate changes in intracranial pressure (ICP) and cerebral hemodynamics in infants with congenital heart disease undergoing the Glenn procedure, focusing on the relationship between superior vena cava pressure and estimated ICP. DESIGN: A single-center prospective cohort study. SETTING: The study was conducted in a cardiac center over 4 years (2019-2022). PATIENTS: Twenty-seven infants with congenital heart disease scheduled for the Glenn procedure were included in the study, and detailed patient demographics and primary diagnoses were recorded. INTERVENTIONS: Transcranial Doppler (TCD) ultrasound examinations were performed at three time points: baseline (preoperatively), postoperative while ventilated (within 24-48 hr), and at discharge. TCD parameters, blood pressure, and pulmonary artery pressure were measured. MEASUREMENTS AND MAIN RESULTS: TCD parameters included systolic flow velocity, diastolic flow velocity (dFV), mean flow velocity (mFV), pulsatility index (PI), and resistance index. Estimated ICP and cerebral perfusion pressure (CPP) were calculated using established formulas. There was a significant postoperative increase in estimated ICP from 11 mm Hg (interquartile range [IQR], 10-16 mm Hg) to 15 mm Hg (IQR, 12-21 mm Hg) postoperatively (p = 0.002) with a trend toward higher CPP from 22 mm Hg (IQR, 14-30 mm Hg) to 28 mm Hg (IQR, 22-38 mm Hg) postoperatively (p = 0.1). TCD indices reflected alterations in cerebral hemodynamics, including decreased dFV and mFV and increased PI. Intracranial hemodynamics while on positive airway pressure and after extubation were similar. CONCLUSIONS: Glenn procedure substantially increases estimated ICP while showing a trend toward higher CPP. These findings underscore the intricate interaction between venous pressure and cerebral hemodynamics in infants undergoing the Glenn procedure. They also highlight the remarkable complexity of cerebrovascular autoregulation in maintaining stable brain perfusion under these circumstances.

Association between patent ductus arteriosus flow and home oxygen therapy in extremely preterm infants.

BACKGROUND: Central blood flow measurements include the estimation of right and left ventricular output (RVO, LVO), superior vena cava (SVC) flow, and calculated patent ductus arteriosus (PDA) flow. We aimed to provide an overview of the maturation patterns of these values and the relationship between PDA flow and the need for home oxygen therapy. METHODS: This prospective single-center study was conducted in infants born at <26 weeks of gestation. We performed echocardiographic measurements five times during their life (from the 4th post-natal day to the 36th postmenstrual week). RESULTS: Sixty patients with a mean birth weight of 680 (590, 760) g were included. Postnatal development of LVO and PDA flow peaked at the end of the second postnatal week (427 and 66 mL/kg/min, respectively). The RVO increased between days 4 and 7-8. The SVCF was most stable. The development curves of PDA flow differed between the groups with (n = 28; 47%) and without home oxygen therapy. CONCLUSION: We present the central blood flow values and their postnatal development in infants <26 weeks of gestation. This study demonstrates the association between PDA flow and the future need for home oxygen therapy. IMPACT: This study enriches our knowledge of the long-term development of central blood flow parameters and derived patent ductus arteriosus (PDA) flow in extremely preterm infants (<26 weeks). While pulmonary resistance decreased, PDA flow continued to increase from day 4 to the end of the second week of life. Similarly, left ventricular output increased as a marker of preload. The superior vena cava flow remained stable. The observed association between PDA flow and an unfavorable respiratory outcome is important for future studies focusing on the prevention of chronic lung disease.

Intermittent Occlusion of the Superior Vena Cava to Improve Hemodynamics in Patients With Acutely Decompensated Heart Failure: The VENUS-HF Early Feasibility Study.

BACKGROUND: Reducing congestion remains a primary target of therapy for acutely decompensated heart failure. The VENUS-HF EFS (VENUS-Heart Failure Early Feasibility Study) is the first clinical trial testing intermittent occlusion of the superior vena cava with the preCARDIA system, a catheter mounted balloon and pump console, to improve decongestion in acutely decompensated heart failure. METHODS: In a multicenter, prospective, single-arm exploratory safety and feasibility trial, 30 patients with acutely decompensated heart failure were assigned to preCARDIA therapy for 12 or 24 hours. The primary safety outcome was a composite of major adverse cardiovascular and cerebrovascular events through 30 days. Secondary end points included technical success defined as successful preCARDIA placement, treatment, and removal and reduction in right atrial and pulmonary capillary wedge pressure. Other efficacy measures included urine output and patient-reported symptoms. RESULTS: Thirty patients were enrolled and assigned to receive the preCARDIA system. Freedom from device- or procedure-related major adverse events was observed in 100% (n=30/30) of patients. The system was successfully placed, activated and removed after 12 (n=6) or 24 hours (n=23) in 97% (n=29/30) of patients. Compared with baseline values, right atrial pressure decreased by 34% (17±4 versus 11±5 mm Hg, P<0.001) and pulmonary capillary wedge pressure decreased by 27% (31±8 versus 22±9 mm Hg, P<0.001). Compared with pretreatment values, urine output and net fluid balance increased by 130% and 156%, respectively, with up to 24 hours of treatment (P<0.01). CONCLUSIONS: We report the first-in-human experience of intermittent superior vena cava occlusion using the preCARDIA system to reduce congestion in acutely decompensated heart failure. PreCARDIA treatment for up to 24 hours was well tolerated without device- or procedure-related serious or major adverse events and associated with reduced filling pressures and increased urine output. These results support future studies characterizing the clinical utility of the preCARDIA system. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03836079.

Regularly irregular atrial rhythm after superior vena cava isolation: Another manifestation of sinoatrial node injury?

The present case described an unusual clinical manifestation of the sinoatrial node (or sinoatrial junction) injury during superior vena cava isolation.

The use of laser lead extraction sheath in the presence of supra-cardiac occlusion of the central veins for cardiac implantable electronic device lead upgrade or revision.

BACKGROUND: The implantation of cardiac implantable electronic devices (CIED) has increased in the last decades with improvement in the quality of life of patients with cardiac rhythm disorders. The presence of bilateral subclavian, innominate or superior vena cava obstruction is a major limitation to device revision and/or upgrade. METHODS AND MATERIAL: This is retrospective study of patients who underwent laser-assisted lead extraction (LLE) (GlideLight laser sheath, Spectranetics Corporation, Colorado Springs, USA) with lead revision or upgrade using the laser sheath as a guide rail. Patients with known occlusion, severe stenosis or functional obstruction of the venous access vessels with indwelling leads were included in this study. RESULTS: 106 patients underwent percutaneous LLE with lead revision and/or upgrade. Preoperative known complete occlusion or severe stenosis of access veins was present in 23 patients (21.5%). More patients with implantable cardioverter-defibrillator (ICD) underwent LLE (64.1%) than patients with CRT-Ds (24.5%) and pacemaker patients (11.3%). In total 172 leads were extracted: 79 (45.9%) single-coil defibrillator leads, 35 (20.3%) dual-coil defibrillator leads, 31 (18.0%) right atrial leads, 24 (13.9%) right ventricular leads and three (1.7%) malfunctional coronary sinus left ventricular pacing leads. The mean age of leads was 99.2±65.6 months. The implantation of new leads after crossing the venous stenosis/obstruction was successful in 98 (92.4%) cases. Postoperative complications were pocket hematoma in two cases and wound infection in one case. No peri-operative and no immediate postoperative death was recorded. One intraoperative superior vena cava tear was treated by immediate thoracotomy and surgical repair. CONCLUSION: In a single-center study on LLE in the presence of supra-cardiac occlusion of the central veins for CIED lead upgrade and revision we could demonstrate a low procedural complication rate with no procedural deaths. Most of the leads could be completely extracted to revise or upgrade the system. Our study showed a low complication rate, with acceptable mortality rates.

High Output Cardiovascular Physiology and Outcomes in Fetal Diagnosis of Vein of Galen Malformation.

Vein of Galen aneurysmal malformation (VGAM) is a rare anomaly associated with poor outcomes from high output cardiac failure and neurologic complications. Studies addressing fetal cardiovascular status and outcomes in this population are limited. A single-center retrospective review was conducted on patients with a prenatal diagnosis of VGAM who underwent a fetal echocardiogram between January 2015 and July 2019. Fetal echocardiographic data, brain magnetic resonance imaging (MRI) findings and outcomes were collected. Nine fetuses [median gestational age at echocardiogram 34 (1.1) weeks] were included. All patients had superior vena cava dilation and reversal of diastolic flow in the transverse aortic arch. Median cardiothoracic (CT) ratio was 0.39 (0.09). Right ventricular (RV) and left ventricular (LV) dysfunction was present in 66% and 11% fetuses, respectively. Four out of five patients that underwent postnatal endovascular neurosurgical interventions at our center were alive at follow-up (mean 2.7 years). Of the non-survivors (n = 5), 3 received comfort care because of severe brain damage and died in the neonatal period. Non-survivors more commonly had > mild tricuspid regurgitation (TR) (40% vs. 25%) and > mild RV dilation (60% vs. 25%). Combined cardiac index (CCI) was higher in non-survivors when compared to survivors (672.7 vs. 530.2 ml/kg/min, p = 0.016). Fetuses with significant parenchymal damage on brain MRI tended to have a higher CCI than those without (979.8 vs. 605.0 ml/kg/min, p = 0.047). RV dysfunction, TR and elevated CCI are more commonly seen in non-survivors with VGAM. A higher CCI is seen in those deemed untreatable due to significant parenchymal volume loss. Future multicenter studies are needed to assess for prenatal prediction of outcomes in this high-risk population.

Depolarization of the Atrial Subepicardium in Rats with Experimentally Induced Pulmonary Hypertension.

Using an experimental model of pulmonary hypertension in rats (monocrotaline in a dose of 60 mg/kg), we revealed an additional focus of early excitation in the zone where the pulmonary veins enter the left atrium, in addition to the main focus in the sinoatrial node. Pulmonary hypertension leads to the formation of regions of early activation in the right and left atria and a significant change in the sequence of atrial depolarization. Propagation of independent excitation waves in the right and left atria increases heterogeneity of depolarization and leads to the formation of atrial arrhythmias.

Endovascular Treatment of Malignant Superior Vena Cava Syndrome through Upper-Limb Access: A Comparison between Venous-Dedicated and Conventional Stents.

PURPOSE: To retrospectively evaluate the technical and clinical outcomes of superior vena cava (SVC) stent placement through upper-limb venous access in malignant SVC syndrome (SVCS) and compare the efficacy of different nitinol stent types. MATERIALS AND METHODS: Between 2006 and 2018, 156 patients (132 male; mean age, 62 y; age range, 33-81 y) underwent SVC stent placement for malignant obstructions through upper-limb venous access with 1 of 3 types of nitinol stent: 1 venous-dedicated (Sinus-XL stent) and 2 non-venous-dedicated (E-Luminexx Vascular Stent and Protégé GPS). Cases of common femoral vein access or non-nitinol stents were excluded from further analysis. The mean duration of follow-up was 8 mo. RESULTS: Technical success was achieved in 99.3% of cases. One patient died during the procedure as a result of cardiac tamponade. Balloon predilation was performed in 10 patients and postdilation in 126. Mean procedural time was 34.4 min (range, 18-80 min). Overall survival rates were 92.3%, 57.3%, and 26.8%, and overall primary patency rates were 94.5%, 84.8% and 79.6%, at 1, 6, and 12 mo, respectively. There were no statistically significant differences in primary patency rates between venous- and non-venous-dedicated stents or among different Stanford SVCS grading groups (P > .05). CONCLUSIONS: SVC stent placement through an upper-limb approach is a safe, fast, and effective technique. There is no evident benefit of venous-dedicated vs non-venous-dedicated stents in the treatment of malignant SVCS.

Congenital subclavian-superior vena cava arteriovenous fistula with initial stenosis in an adult: a case report.

BACKGROUND: A subclavian-superior vena cava arteriovenous fistula is usually acquired and secondary to trauma or operations, while congenital causes are very rare. A congenital arteriovenous fistula leads to congestive heart failure soon after birth and is typically diagnosed in early infancy. CASE PRESENTATION: We present an unusual case of a 21-year-old female suffering from new-onset heart failure at 20 years old who was diagnosed with a congenital arteriovenous fistula from the right subclavian artery to the superior vena cava (RSA-to-SVC) with stenosis at the proximal initial site of the fistula. The patient successfully underwent transcatheter occlusion for the fistula and had a significant improvement in symptoms at the 3-month follow-up. CONCLUSIONS: An RSA-to-SVC fistula is a very rare congenital disorder that can lead to shunt-related heart failure. If there is an indication for closure, as with the patient presented, percutaneous device closure can be considered a reasonable option.

Low preoperative superior vena cava blood flow predicts bidirectional cavopulmonary shunt failure.

BACKGROUND: In this study we sought to determine whether preoperative superior vena cava (SVC) blood flow measured using cardiac magnetic resonance (CMR) predicts physiology and clinical outcome after bidirectional cavopulmonary shunt (BCPS). METHODS: The retrospective single-center study included 65 (2012-2017) patients who underwent BCPS. Preoperative CMR imaging, echocardiography, catheterization, and clinical outcomes were reviewed. SVC flow was measured using phase contrast CMR. The Kaplan-Meier method and Cox regression was used for BCPS takedown-free survival and predictor analyses. RESULTS: The absolute and indexed SVC flow was 0.5 (interquartile range [IQR], 0.4-0.7) L/min and 1.7 (IQR, 1.4-2.0) L/min/mm2 respectively, which was comparable with the SVC blood flow volume previously measured. The median age and body weight at BCPS was 6.5 (IQR, 5.5-8.5) months and 6.9 (IQR, 6.0-7.7) kg. After follow-up, at a median of 17.1 (IQR, 7.9-41.3) months, 14 patients (21.5%) underwent the Fontan completion and 40 (61.5%) with BCPS physiology were waiting for the Fontan completion. The 11 remaining patients (16.9%), included those who underwent takedown (n = 7; 10.8%) or died with a BCPS (n = 4; 6.2%). Severe hypoxia was the leading cause of mortality, directly accounting for two-thirds of deaths (66.6%; 6/9). The BCPS takedown-free survival was 96.8% at 6 months, and 79.9% at 3 years. Preoperative SVC blood flow was significantly positively correlated with early post-BCPS arterial saturation (P = .00). The multivariable analysis showed SVC flow was the only factor associated with BCPS failure (hazard ratio, 0.186; P = .04) among the predictors related to the pre-BCPS anatomy and physiology. CONCLUSIONS: SVC blood flow might be as critically important as pulmonary artery anatomic and physiologic parameters in the evaluation of BCPS candidacy in the single-ventricle population.

Beyond Pulmonary Vein Isolation in Nonparoxysmal Atrial Fibrillation: Posterior Wall, Vein of Marshall, Coronary Sinus, Superior Vena Cava, and Left Atrial Appendage.

The optimal ablation strategy for non-paroxysmal atrial fibrillation remains controversial. Non-PV triggers have been shown to have a major arrhythmogenic role in these patients. Common sources of non-PV triggers are: posterior wall, left atrial appendage, superior vena cava, coronary sinus, vein of Marshall, interatrial septum, crista terminalis/Eustachian ridge, and mitral and tricuspid valve annuli. These sites are targeted empirically in selected cases or if significant ectopy is noted (with or without a drug challenge), to improve outcomes in patients with non-paroxysmal atrial fibrillation. This article focuses on summarizing the current evidence and the approach to mapping and ablation of these frequent non-PV trigger sites.

Superior vena cava flow: Role, assessment and controversies in the management of perinatal perfusion.

The superior vena cava (SVC) is a large vein responsible for the venous return of blood from structures located superior to the diaphragm. The flow in the SVC can be assessed with Doppler ultrasound and can be used as a proxy for cerebral perfusion. Early clinical research studies showed that low SVC flow, particularly if for a prolonged period, was associated with short term morbidity such as intraventricular hemorrhage, mortality, and poorer neurodevelopmental outcomes. However, these findings have not been consistently reported in more recent studies, and the role of SVC flow in early management and as a predictor of poor long-term neurodevelopment has been questioned. This paper provides an overview of SVC assessment, the expected range of findings, and reviews the role of SVC flow as a diagnostic and monitoring tool for the assessment of perinatal perfusion.

Efficacy of endovascular Z-configuration stenting for malignant versus nonmalignant caval obstruction.

OBJECTIVE: The objective of this study was to assess factors associated with symptom resolution after endovascular stenting for superior or inferior vena cava syndrome. METHODS: Eighty-six consecutive vena cava Z-configuration stent placements in 82 patients (53 ± 14 years old) at a single institution were reviewed for patient demographics, comorbidities, and durability of stent patency (also evaluated were persistent or recurrent symptoms, stent occlusion, and need for repeated stenting). Logistic regression was used to identify independent factors associated with stent patency, and Φ coefficients and analysis of variance were used to compare cases subdivided by lesion location (superior vena cava, inferior vena cava) and the presence or absence of malignant disease. RESULTS: Clinical follow-up was available in 77 of 86 (90%) cases. Technical success with clinical failure (persistent symptoms) occurred in 40% of these cases with a median follow-up of 67 (interquartile range, 14-570) days and mortality rate of 63% during this period. Malignant obstructions had a significantly higher clinical failure rate of 54% compared with 15% for nonmalignant obstructions (Φ = 0.34; P = .002). However, only metastatic disease was independently associated with clinical failure when controlling for demographics, other comorbidities, and differential follow-up (adjusted odds ratio, 8.27; 95% confidence interval, 2.79-24.50). CONCLUSIONS: Vena cava Z-stenting effectively resolves symptoms in 85% of nonmalignant obstructions compared with only 46% of malignant obstructions. Patients should be counseled accordingly, and those with malignant obstructions may require closer follow-up to evaluate the need for reintervention and goals of care.

Electrical isolation of the superior vena cava using second-generation cryoballoon in patients with atrial fibrillation.

BACKGROUND: The safety and efficacy of superior vena cava (SVC) isolation using second-generation cryoballoon (CB) ablation remain unknown. METHODS: A total of 26 (3.2%) patients with SVC-related paroxysmal atrial fibrillation (AF) from a consecutive series of 806 patients who underwent second-generation CB were included. Pulmonary vein isolation was initially achieved by CB ablation. If the SVC trigger was determined, the electrical isolation of SVC isolation was performed using the second-generation CB. RESULTS: Real-time SVC potential was observed in all patients. Isolation of the SVC was successfully accomplished in 21 (80.8%) patients. The mean number of freeze cycles in each patient was 2.1 ± 1.1. The mean time to isolation and ablation duration were 22.5 ± 14.2 seconds and 94.5 ± 22.3 seconds, respectively. A transient phrenic nerve (PN) injury was observed in five patients (19.2%). There were two patients (7.7%) experienced reversible sinus node injury during the first application. During a mean follow-up period of 13.2 ± 5.8 months, four patients (15.4%) had atrial arrhythmia recurrences. CONCLUSION: Isolation of SVC using the second-generation 28-mm CB is feasible when SVC driver during AF is identified. Vigilant monitoring of PN function during CB ablation of SVC is needed to avoid PN injury.

Complications of retained cardiac defibrillator coil left in situ.

A 42-year-old man presented to a regional hospital emergency department with a 4-day history of haemoptysis, shortness of breath, pleuritic chest pain, productive cough and subjective fevers. This episode was the third similar presentation in a 2-month period. The patient was known to have dilated cardiomyopathy secondary to amphetamine use and had previously required insertion of automated implantable cardiac defibrillator (AICD). Due to recurrent complications, the AICD had been replaced on two occasions and a superior vena cava (SVC) lead left in situ on its final removal. Clinical examination and investigations revealed lower respiratory tract infection and transthoracic echocardiogram revealed severe left ventricular failure with an ejection fraction of 16%. The patient was admitted under the general medical team for treatment and investigation of suspected bacteraemia and septicaemia secondary to colonisation of the retained AICD lead. He spent 6 days as an in-patient and was discharged on home where he was to be followed up by the advanced heart failure team in a tertiary centre for consideration of new AICD insertion and to explore possibility of retained coil removal. This case report discusses the concerns surrounding retained SVC leads and potential clinical sequalae. As this patient presented three times within a period of 2 months, it was suspected retained SVC lead was a predisposing factor for recurrent lower respiratory infection.

Transcatheter creation of bidirectional cavopulmonary connections by needle punctures in two patients.

We report on two patients who received a transcatheter cavopulmonary connection by a needle puncture under deep conscious sedation. In both patients, the vessel-to-vessel connection was achieved by a venous access into the superior caval vein and direct needle puncture of the pulmonary artery. The two cavopulmonary anastomoses were held open by a covered stent and a bare-metal stent, respectively.