Superior Vena Cava Pressure Research Articles

Validating the Concept of Mechanical Circulatory Support with a Rotary Blood Pump in the Inferior Vena Cava in an Ovine Fontan Model.

Right-sided mechanical support of the Fontan circulation by existing devices has been compounded by the cross-sectional design of vena cava anastomosis to both pulmonary arteries. Our purpose was to investigate whether increasing inferior vena cava (IVC) flow with a rotary blood pump in the IVC only in an ovine animal model of Fontan would lead to acceptable superior vena cava (SVC) pressure. To achieve this, a Fontan circulation was established in four female sheep by anastomosing the SVC to the main pulmonary artery (MPA) and by interposing a Dacron graft between the IVC and the MPA. A rotary blood pump was then introduced in the graft, and the effect of incremental flows was observed at increasing flow regimen. Additionally, to stimulate increased pulmonary resistance, the experience was repeated in each animal with the placement of a restrictive band on the MPA distally to the SVC and Dacron graft anastomosis. Circulatory support of IVC flow alone increased the systemic cardiac output significantly, both with and without banding, indicating the feasibility of mechanical support of the Fontan circulation by increasing the flow only in the inferior vena cava. The increase in SVC pressure remained within acceptable limits, indicating the potential effectiveness of this mode of support. The findings suggest that increasing the flow only in the inferior vena cava is a feasible method for mechanical support of the Fontan circulation, potentially leading to an increase in cardiac output with acceptable increases in superior vena cava pressure.

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

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. A single-center prospective cohort study. The study was conducted in a cardiac center over 4 years (2019-2022). 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. 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. 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. 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.

The clinical and hemodynamic characteristics of pulmonary hypertension in patients with OSA-COPD overlap syndrome

BackgroundOur study aimed to assess the clinical and hemodynamic characteristics of pulmonary hypertension (PH) in patients with overlapping obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD), referred to OSA-COPD overlap syndrome (OS). MethodsWe enrolled a total of 116 patients with OS, COPD, or OSA who underwent right heart catheterization (RHC) due to suspected PH. We conducted a retrospective analysis of the clinical and hemodynamic characteristics of these patients. ResultsAmong the three groups (OS group, n = 26; COPD group, n = 36; OSA group, n = 54), the prevalence of PH was higher in the OS group (n = 17, 65.4%)compared to OSA group (n = 26,48.1%) and COPD group (n = 20,55.6 %). Among three groups with PH, the superior vena cava pressure (CVP) and right ventricular pressure (RAP) were higher in the OS group than in the OSA group (P < 0.05). Patients in the OS and COPD groups had higher pulmonary artery wedge pressure (PAWP) than in the OSA group (14.88 ± 4.79 mmHg, 13.45 ± 3.68 mmHg vs. 11.00 ± 3.51 mmHg, respectively, P < 0.05). OS patients with PH exhibited higher respiratory event index (REI), time spent with SpO2 <90%, oxygen desaturation index (ODI), minimal SpO2 (MinSpO2) and mean SpO2 (MSpO2) compared to OS patients without PH. After adjusting for potential covariates, we found that MinSpO2 (OR 0.937, 95 % CI 0.882–0.994, P = 0.032), MSpO2 (OR 0.805, 95% CI 0.682–0.949, P = 0.010), time spent with SpO2 <90% (OR 1.422, 95% CI 1.137–1.780, P = 0.002), and FEV1 % pred (OR 0.977, 95 % CI 0.962–0.993, P = 0.005) were related to the development of PH. ConclusionsPatients with OS showed higher prevalence of PH, along with higher PAWP, CVP and RAP. Worse nocturnal hypoxemia was found in OS patients with PH.

Ascites in Animals With Right Heart Failure: Correlation With Lymphatic Dysfunction.

Background Congestive heart failure is a leading cause of morbidity and mortality worldwide. One of the signs of congestive heart failure is fluid overload including pulmonary edema, peripheral edema, and ascites. The cause of fluid overload remains incompletely understood, and management of these patients continues to be a challenge. The role of lymphatic circulation abnormalities in the cause and pathophysiology of fluid overload also remains unclear. Here we report on a study in a large animal model of right heart failure caused by severe tricuspid regurgitation comparing cardiovascular and lymphatic findings in a group of animals that did not develop ascites with a group of animals that developed ascites. Methods and Results Thirteen Yorkshire pigs were included in this study divided into 2 groups. Group 1 included 6 animals that did not develop ascites, and Group 2 included 7 animals that had developed ascites. The groups were compared on hemodynamic parameters as well as comparison of the animal's lymphatic anatomy and function. There was no difference between the groups in degree of tricuspid regurgitation and central venous pressure, with inferior vena cava pressure measuring 11.6±1.6 versus 13.2±3.7 (P=0.534) and superior vena cava pressure measuring 12.0±2.3 versus 13.7±3.2 (P=0.366). There was also no difference between the groups in all measured hemodynamic parameters, including right ventricular pressure, pulmonary artery pressure, and left ventricular function. The weighted liver size in the ascites group was significantly larger than in the nonascites group (30.3±12.4 versus 63.3±14.0 mL/kg, respectively; P=0.001). The 2 groups also differed in the number of animals with regurgitant thoracic duct flow (Group 1: 1/6,17% versus Group 2: 6/7, 86%; P=0.029) and the minimal thoracic duct diameter (Group 1: 2.3±0.3 versus Group 2: 4.2±2.2; P=0.035). Conclusions In animals with right heart failure caused by severe tricuspid regurgitation, fluid overload did not correlate with hemodynamic parameters but rather with changes in the lymphatic system, including regurgitant lymphatic flow, minimal thoracic duct diameter, and liver size. This study is consistent with lymphatic dysfunction and not cardiovascular function playing a significant role in the cause of fluid overload. Further studies are needed to confirm these findings.

Abstract 14757: Affected Patients and Clinical Outcomes After Transcatheter Relief of Superior Vena Cava Stenosis

Background: Obstruction of the superior vena cava (SVC) is thought to be mostly iatrogenic. Transcatheter interventions relieve stenosis with good long-term results, but there is a paucity of published data. We aim to describe patient characteristics and outcomes after transcatheter SVC intervention. Methods: Single-center, retrospective study of patients who underwent transcatheter SVC intervention from December 2006 to January 2020. Patient characteristics included age, gender, height, weight, and BSA. Clinical parameters included congenital heart disease (CHD), orthotopic heart transplant (OHT), upper extremity central venous line (CVL), extracorporeal membranous oxygenation (ECMO), mortality, and symptoms. Procedural data included pre- and post-intervention SVC pressure gradient, dimensions, and complications. Results: A total of 42 patients (median age 1.5 years, IQR [0.31-15], 64.2% male) underwent 81 procedures with 1 major complication, and 20 patients (47.6%) had re-interventions. 12 patients (31.5%) had symptoms. Affected patient groups were as follows: history of CVL (92.9%), CHD (76.2%), post-OHT (42.9%), and post-ECMO (30.9%). Those who underwent initial balloon angioplasty were significantly younger (mean ± SD: 3.9 ± 6.8 vs. 13.1 ± 11.3 years, p&lt;0.01) and smaller (15.9 ± 20.4 vs. 39.9 ± 31.2 kg, p&lt;0.01) than those with initial stent. A lower pressure gradient and larger post-intervention dimension was achieved after stenting (p&lt;0.01). Re-intervention rates were similar; 50% after balloon and 43.8% after stent, but nearly half of the angioplasty cohort resolved after repeat angioplasty alone, while most stents (85.7%) required serial re-dilation. Affected patient groups were not associated with re-intervention, and there were no significant differences in patient or procedural characteristics between those who did and did not require re-intervention. Conclusions: We describe at-risk groups who warrant surveillance of SVC stenosis in the setting of a low-symptom rate. Strongly consider balloon angioplasty as initial therapy, which may avoid the need for stent and subsequent re-dilations associated with growth. Re-intervention is likely after balloon angioplasty and stenting, but both are safe and effective.

Myocardial Edema Provides a Link Between Pulmonary Arterial Hypertension and Pericardial Effusion.

Myocardial Edema Provides a Link Between Pulmonary Arterial Hypertension and Pericardial Effusion.

Characterization of the Ejector Pump Performance for the Assisted Bidirectional Glenn Procedure

This study introduces an algebraic model informed by computational fluid dynamics (CFD) simulations to investigate the performance of the assisted bidirectional Glenn (ABG) operation on a broad range of conditions. The performance of this operation, as measured by the superior vena cava (SVC) pressure, depends on the nozzle area in its ejector pump and the patient’s pulmonary vascular resistance (PVR). Using the developed algebraic model to explore this two-dimensional parameter space shows that the ejector pump can create a pressure difference between the pulmonary artery and the SVC as high as 5 mmHg. The lowest SVC pressure is produced at a nozzle area that decreases linearly with the PVR such that, at PVR =4.2 (Wood units-m2), there is no added benefit in utilizing the ejector pump effect (optimal nozzle area is zero, corresponding to the bidirectional Glenn circulation). At PVR =2 (Wood units-m2), the SVC pressure can be lowered to less than 4 mmHg by using an optimal nozzle area of ≈2.5 mm2. Regardless of the PVR, adding a 2 mm2 nozzle to the baseline bidirectional Glenn boosts the oxygen saturation and delivery by at least 15%. The SVC pressure for that 2 mm2 nozzle remains below 14 mmHg for all PVRs less than 7 Wood units-m2. The mechanical efficiency of the optimal designs consistently remains below 30%, indicating the potential for improvement in the future. A good agreement is observed between the algebraic model and high-fidelity CFD simulations.

Effectiveness of sharp recanalization of superior vena cava-right atrium junction occlusion.

BACKGROUNDConventional recanalization techniques may fail in patients with completely occluded superior vena cava (SVC).AIMTo analyze the effectiveness and complications of sharp recanalization for completely occluded SVC. METHODSThis was a retrospective study of patients that underwent puncture and recanalization of the SVC between January 2016 and December 2017 at our hospital. Sharp recanalization was performed using the RUPS-100 system. The patients were followed for 12 mo. The main outcomes were the patency rate of SVC and arteriovenous fistula flow during dialysis. RESULTSThe procedure was successful in all 14 patients (100%). Blood pressure in the distal SVC decreased in all 14 cases (100%) from 26.4 ± 2.7 cmH2O to 14.7 ± 1.3 cmH2O (P < 0.05). The first patency rates of the SVC at 24 h and at 3, 6, 9 and 12 mo after sharp recanalization were 100%, 92.9%, 85.7%, 78.6% and 71.4%, respectively. There were two (14.3%) severe, one (7.1%) moderate and one (7.1%) minor complication. The severe complications included one case of pericardial tamponade and one case of hemothorax.CONCLUSIONThe results suggest that sharp recanalization can be an additional tool to extend or renew the use of an occluded upper extremity access for hemodialysis. This could be of use in patients with long-term maintenance hemodialysis in whom the maintenance of central venous access is often a challenge.

An Efficient Assisted Bidirectional Glenn Design With Lowered Superior Vena Cava Pressure for Stage-One Single Ventricle Patients.

Recently, the assisted bidirectional Glenn (ABG) procedure has been proposed as an alternative to the modified Blalock-Taussig shunt (mBTS) operation for neonates with single-ventricle physiology. Despite success in reducing heart workload and maintaining sufficient pulmonary flow, the ABG also raised the superior vena cava (SVC) pressure to a level that may not be tolerated by infants. To lower the SVC pressure, we propose a modified version of the ABG (mABG), in which a shunt with a slit-shaped nozzle exit is inserted at the junction of the right and left brachiocephalic veins. The proposed operation is compared against the ABG, the mBTS, and the bidirectional Glenn (BDG) operations using closed-loop multiscale simulations. Both normal (2.3 Wood units-m2) and high (7 Wood units-m2) pulmonary vascular resistance (PVR) values are simulated. The mABG provides the highest oxygen saturation, oxygen delivery, and pulmonary flow rate in comparison to the BDG and the ABG. At normal PVR, the SVC pressure is significantly reduced below that of the ABG and the BDG (mABG: 4; ABG: 8; BDG: 6; mBTS: 3 mmHg). However, the SVC pressure remains high at high PVR (mABG: 15; ABG: 16; BDG: 12; mBTS: 3 mmHg), motivating an optimization study to improve the ABG hemodynamics efficiency for a broader range of conditions in the future. Overall, the mABG preserves all advantages of the original ABG procedure while reducing the SVC pressure at normal PVR.

Intra-Extracardiac Total Cavopulmonary Connection for Patients With Anatomical Complexity

Currently, the extracardiac conduit total cavopulmonary connection (eTCPC) is the most widely used for Fontan modification worldwide. Nevertheless, there have been some cases that are difficult for performing eTCPC because of their anatomical complexity, such as apicocaval juxtaposition. For such cases, in 2002, we introduced the intra-extracardiac TCPC (ieTCPC). We reviewed our 20-year single-center experience with 316 TCPC patients to compare eTCPC (n= 277) and ieTCPC (n= 39) in terms of mortality and morbidity. ieTCPC was indicated for the cases in which there was concern that the TCPC conduit would be too curved for ordinary eTCPC. Early death occurred in 1 patient and late death occurred in 15 patients. The actuarial survival rate in the eTCPC and the ieTCPC groups at 10 years were 95.1% and 100.0%, respectively. There was no significant difference in actuarial survival between eTCPC and ieTCPC patients. In the multivariate analysis, preoperative superior vena cava pressure and preoperative oxygen saturation were found to be the independent predictor for postoperative mortality. There was also no significant difference in actuarial rate of freedom from late-occurring complications between eTCPC and ieTCPC groups. In the multivariate analysis, dominant right ventricle and preoperative SVC pressure were independent predictors for late-occurring complications. The clinical outcomes in patients who undergo eTCPC and ieTCPC appear to be excellent, with low mortality and morbidity rates in the midterm. ieTCPC may be a good option for TCPC cases with anatomical complexity such as apicocaval juxtaposition and separated hepatic vein drainage.

Hemodynamics in a bidirectional Glenn Shunt supplemented with a modified Blalock-Taussig shunt: Computational fluid dynamics assessment

The bidirectional Glenn Shunt (BGS), superior vena cava (SVC) to right pulmonary artery (RPA) is occasionally supplemented with a left modified Blalock-Taussig shunt (mBTS) when PA growth is inadequate. Little is known about hemodynamics when BGS's low-velocity steady flow interacts with mBTS's high-velocity pulsatile flow. We employed simulations of flow in cavopulmonary pathways consisting of internal jugular, subclavian and innominate veins, SVC, RPA, LPA and mBTS, using computational fluid dynamics (CFD) to numerically solve (finite volume method) the Navier-Stokes equations subject to in vivo flow rates at the inlets and measured or calculated pressures at the outlets of the cavopulmonary system. For normal size (9 mm) PAs and a BGS alone, SVC pressure was 12.3 mmHg, RPA and LPA 12.2 mmHg; PA outlets 12 mmHg. We then compared results for the BGS with a 4 mm mBTS. I) With normal-size PAs, SVC pressure was 14.3 mmHg, RPA 13.3 mmHg and LPA 12.9 mmHg; PA outlets 12 mmHg. Wall shear stress (WSS), RPA 6.2 Pa and LPA 53.7 Pa. II) With normal size (9 mm) RPA but small (5.1 mm) LPA, SVC pressure was 15.1 mmHg, RPA 13.8 mmHg and LPA 17.4 mmHg; RPA outlet 12 mmHg and LPA 14 mmHg. WSS, RPA 13.2 Pa and LPA 71 Pa. Normal PA WSS is ~ 2 Pa. *All parameters were averaged over the cardiac cycle. The mBTS created vortices which markedly elevated WSS. High WSS can induce PA luminal cell expression of coagulatory molecules and initiate platelet aggregation. However, WSS lessened as flow velocity decreased from LPA to RPA. This is important since in vitro studies demonstrate WSS's harmful effect on PA endothelium is ameliorated under decelerating flow. In conclusion, for a BGS with a mBTS, SVC pressure became cyclic and significantly increased and thrombogenic vortices were established in the PAs.

Lymphatic Decompression Concomitant With Fontan/Kreutzer Procedure: Early Experience.

To present a strategy for identifying patients at risk of lymphatic failure in the setting of planned Fontan/Kreutzer completion, allowing a tailored surgical approach. Since January 2017, clinical evaluation before performance of the Fontan/Kreutzer procedure included T2-weighted magnetic resonance imaging (MRI) lymphangiography. Thoracic lymphatic abnormalities were categorized using a scale of I to IV according to progression of severity. Patients with severe lymphatic abnormalities (types III and IV) underwent Fontan/Kreutzer with lymphatic decompression via connection of the left jugular-subclavian junction containing the thoracic duct to the systemic atrium (group A). Thirteen patients were enrolled. Magnetic resonance imaging showed type I abnormalities in four cases (30.7%), II in four (30.7%), III in two (15.3%), and IV in three (23.3%). Patients in types III and IV underwent a Fontan/Kreutzer with lymphatic decompression (group A, n = 5), while patients in types I and II underwent a fenestrated extracardiac Fontan/Kreutzer procedure without lymphatic decompression (group B, n = 8). Preoperatively, there were no differences in age, weight, ventricular dominance (right vs left), superior vena cava pressure, incidence of chylothorax after previous superior cavopulmonary anastomosis (Glenn), or need for concomitant procedures at Fontan/Kreutzer completion. There were no differences in procedural times between the groups, nor were there differences in mortalities and Fontan/Kreutzer takedowns. There were no statistically significant differences in early and late morbidity between the two groups with the exception of total volume of effusions output postoperatively. At median follow-up of 18 months (range, 4-28 months), all patients in group A are in New York Heart Association class 1 with no differences between groups in arterial oxygen saturation. Lymphatic decompression during Fontan/Kreutzer procedure was successfully performed in patients identified by MRI as predisposed to lymphatic failure. A larger cohort of patients and longer follow-up are required to determine the efficacy of this approach in preventing early- and long-term Fontan/Kreutzer failure.

Does Extrathoracic Jugulo-Femoral Venous Shunt Avoid Cardiopulmonary Bypass in Glenn Bi-Directional Shunt Procedure?

ObjectiveThe aim of the present study was to evaluate the efficacy of extrathoracic jugulo-femoral venous shunt (JFVS) in avoiding the need for cardiopulmonary bypass (CPB) during the bi-directional Glenn shunt (BDGS) procedure.MethodsA total of 40 patients aged between 9 and 36 months were enrolled in the present study. The patients were classified into two groups, group A (n=20) in which the patients had no veno-venous shunt and group B (n=20) in which the patients had extrathoracic JFVS. Patients requiring CPB, arterial oxygen saturation (SaO2), heart rate, mean arterial pressure (MAP) and central venous pressure (CVP) were recorded during surgery. Postoperative time of intubation, intensive care unit (ICU) and hospital length of stays and neurological complications were also recorded.ResultsThe number of patients who needed urgent CPB was greater in group A than in group B. Intraoperative MAP was significantly lower in group A than in group B 10 min after clamping of the superior vena cava (SVC) and 30 min after declamping of the SVC. The CVP was significantly lower, and arterial SaO2 was significantly higher in group B than in group A 10 min after clamping of the SVC. The duration of postoperative intubation was significantly shorter in group B than in group A, and the ICU length of stay was shorter in group B than in group A. The hospital length of stay was similar in both groups. Postoperative neurological deficits were comparable in both groups.ConclusionThe use of extrathoracic JFVS during the BDGS procedure avoided the use of CPB, maintained MAP and prevented any significant increase in SVC pressure.

Perioperative Assessment of Cerebral Oxygen Metabolism in Infants With Functionally Univentricular Hearts Undergoing the Bidirectional Cavopulmonary Connection.

The transition from single-ventricle lesions with surgically placed systemic-to-pulmonary artery shunt to the circulation following a bidirectional cavopulmonary connection results in higher pressure in the superior vena cava when compared with the preceding circulation. The aim of this study was to evaluate the impact of this transition on the perioperative cerebral oxygen metabolism. Prospective observational cohort study. Pediatric critical care unit of a tertiary referral center. Sixteen infants after bidirectional cavopulmonary connection. Cardiac surgery (bidirectional cavopulmonary connection). We measured regional cerebral oxygen saturation, amount of hemoglobin, blood flow velocity, and microperfusion immediately before, 12-24 hours, and 36-48 hours following bidirectional cavopulmonary connection. Based on these measurements, we calculated cerebral fractional tissue oxygen extraction and approximated cerebral metabolic rate of oxygen. Mean pressure in the superior vena cava increased significantly (8 vs 17 mm Hg; p < 0.001) following bidirectional cavopulmonary connection. Mean cerebral oxygen saturation increased from 49.0% (27.4-61.0) to 56.9% (39.5-64.0) (p = 0.008), whereas mean cerebral blood flow velocity decreased from 80.0 arbitrary units (61.9-93.0) to 67.3 arbitrary units (59.0-83.3) (p < 0.001). No change was found in the cerebral amount of hemoglobin and in the cerebral microperfusion. Mean cerebral fractional tissue oxygen extraction (0.48 [0.17-0.63] vs 0.30 [0.19-0.56]; p = 0.006) and approximated cerebral metabolic rate of oxygen (5.82 arbitrary units [2.70-8.78] vs 2.27 arbitrary units [1.19-7.35]; p < 0.001) decreased significantly. Establishment of bidirectional cavopulmonary connection is associated with postoperative improvement in cerebral oxygen metabolism. Cerebral amount of hemoglobin did not increase, although creation of the bidirectional cavopulmonary connection results in significant elevation in superior vena cava pressure. Improvement in cerebral oxygen metabolism was due to lower cerebral blood flow velocity and stable microperfusion, which may indicate intact cerebral autoregulation.

SQUAMOUS CELL CARCINOMA PRESENTING WITH OBSTRUCTION OF THE SUPERIOR VENA CAVA AND CENTRAL AIRWAYS

SESSION TITLE: Tuesday Fellows Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM INTRODUCTION: One mechanism by which cancer causes morbidity/mortality is by mass effect with distortion, compression, or occlusion of nearby anatomical structures. Within the chest, tumors can exert these effects on the airways and vascular structures. This case illustrates the need for urgent intervention in a patient presenting with severe compression of multiple intrathoracic structures. CASE PRESENTATION: A 54 year-old man with chronic tobacco use and limited exposure to healthcare presented to the hospital with gradually progressive shortness of breath over several months, followed by facial swelling, severe wheezing, and recurrent syncope over the past few days. Exam was remarkable for facial flushing and diffuse inspiratory/expiratory wheezing. Laryngoscopy was performed, which did not suggest critical airway edema. Computed tomography (CT) of the chest demonstrated a large right-sided suprahilar mass, with severe compression of the superior vena cava (SVC) and right mainstem bronchus (RMB) and bronchus intermedius, narrowing of the right pulmonary artery and vein, and complete collapse of the right upper lobe. The patient underwent urgent placement of an 11x59mm balloon-expandable covered stent within the SVC, after which the patient reported improvement in facial swelling but minimal improvement in dyspnea. Next, he underwent bronchoscopy, which demonstrated significant extrinsic compression within the right mainstem bronchus; transbronchial needle aspirates of lymph nodes from Stations 4R and 7 were obtained, from which pathology results were consistent with squamous cell carcinoma (SCC). Because of the degree of bronchial compression, and the need for chemotherapy and radiation therapy which could temporarily cause tumoral inflammation and worsen compression/collapse of the right lung, bronchoscopy was repeated, and this time a 12x40mm self-expandable partially-covered stent was placed within the right mainstem bronchus. After this, the patient reported significant improvement in dyspnea, and was discharged to home in stable condition. DISCUSSION: This case describes pulmonary SCC presenting with symptoms of acute SVC syndrome and central airway compression. Lung cancer associated with either of these conditions has dramatically increased morbidity/mortality. In malignant SVC syndrome, stent placement has been shown to reduce SVC pressure and improve symptoms; there is moderate risk of stent re-obstruction. Though not free of risks, endobronchial stent placement can prevent the impending occlusion of a central airway, when surgical or endobronchial resection/debulking is not possible. In recent years, there have been numerous advances in the technology and variety of endobronchial stents for multiple indications. CONCLUSIONS: Malignant extrinsic compression of the SVC and central airways is associated with high morbidity/mortality and can be managed urgently and safely with stent placement. Reference #1: Avasarala SK, Freitag L, & Mehta AC. Metallic endobronchial stents: A contemporary resurrection [published online ahead of print December 11, 2018]. CHEST. doi:10.101/j.chest.2018.12.001. Reference #2: Niu S, Xu YS, Cheng L, & Cao C. Stent insertion for malignant superior vena cava syndrome: Effectiveness and long-term survival. Vascular and Interventional Radiology 2017, 122: 633-638. Reference #3: Mudambi L, Miller R, & Eapen GA. Malignant central airway obstruction. Journal of Thoracic Disease 2017, 9(10): 1087-1110. DISCLOSURES: No relevant relationships by Gabriel Ryan, source=Web Response

Multiscale Modeling of Superior Cavopulmonary Circulation: Hemi-Fontan and Bidirectional Glenn Are Equivalent

Superior cavopulmonary circulation (SCPC) can be achieved by either the Hemi-Fontan (hF) or Bidirectional Glenn (bG) connection. Debate remains as to which results in best hemodynamic results. Adopting patient-specific multiscale computational modeling, we examined both the local dynamics and global physiology to determine if surgical choice can lead to different hemodynamic outcomes. Six patients (age: 3-6 months) underwent cardiac magnetic resonance imaging and catheterization prior to SCPC surgery. For each patient: (1) a finite 3-dimensional (3D) volume model of the preoperative anatomy was constructed to include detailed definition of the distal branch pulmonary arteries, (2) virtual hF and bG operations were performed to create 2 SCPC 3D models, and (3) a specific lumped network representing each patient's entire cardiovascular circulation was developed from clinical data. Using a previously validated multiscale algorithm that couples the 3D models with lumped network, both local flow dynamics, that is, power loss, and global systemic physiology can be quantified. In 2 patients whose preoperative imaging demonstrated significant left pulmonary artery (LPA) stenosis, we performed virtual pulmonary arterioplasty to assess its effect. In one patient, the hF model showed higher power loss (107%) than the bG, while in 3, the power losses were higher in the bG models (18-35%). In the remaining 2 patients, the power loss differences were minor. Despite these variations, for all patients, there were no significant differences between the hF and bG models in hemodynamic or physiological outcomes, including cardiac output, superior vena cava pressure, right-left pulmonary flow distribution, and systemic oxygen delivery. In the 2 patients with LPA stenosis, arterioplasty led to better LPA flow (5-8%) while halving the power loss, but without important improvements in SVC pressure or cardiac output. Despite power loss differences, both hF and bG result in similar SCPC hemodynamics and physiology outcome. This suggests that for SCPC, the pre-existing patient-specific physiology and condition, such as pulmonary vascular resistance, are more deterministic in the hemodynamic performance than the type of surgical palliation. Multiscale modeling can be a decision-assist tool to assess whether an extensive LPA reconstruction is needed at the time of SCPC for LPA stenosis.

Palliative Operations for Cyanotic Congenital Heart Disease with Severely Asymmetrical Pulmonary Arteries

Surgically managing patients with complex congenital heart disease and severely asymmetrical pulmonary arteries is challenging. Here, we report our experience using combined palliative procedures. The medical records of 28 patients with complex congenital heart disease and severely asymmetrical pulmonary arteries who underwent combined palliative procedures between January 2004 and April 2013 were retrospectively reviewed until January 2018. The patients were divided into three groups according to shunt procedure timing: in group A (n = 15), cavopulmonary and systemic-pulmonary shunting were performed simultaneously; in group B (n = 11), systemic-pulmonary shunting was performed first; and in group C (n = 2), cavopulmonary shunt was performed first. Patients were followed for a mean ± standard deviation of 4.18 ± 2.22 years. No operative deaths occurred. There were no postoperative complications in groups B or C, but there was one case of pulmonary effusion and one of chylothorax in group A. The superior vena cava pressures were higher in patients in groups A and B than in those in group C. The ventilatory support duration and intensive care unit stays were longer in group A than in groups B and C (p < 0.01). Hypoplastic pulmonary artery development significantly improved after the use of three systemic-pulmonary shunts (p < 0.05), while the peripheral oxygen saturation increased from 67%±17% preoperatively to 85%±8% postoperatively (p < 0.001). Haemoglobin concentration decreased from 190 ± 34 g/L preoperatively to 136 ± 26 g/L postoperatively (p < 0.001). Two patients underwent double ventricle correction. Two patients underwent Fontan procedure. One patient underwent one and a half ventricle correction. One patient underwent collateral occlusion. Combined palliative procedures can achieve acceptable arterial oxygen saturation without extra volume loading and rescue the hypoplastic pulmonary artery.

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

ObjectiveRight-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. MethodsEach 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. ResultsRequiring 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. ConclusionsPediMag 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.

Risks and Benefits of Using a Commercially Available Ventricular Assist Device for Failing Fontan Cavopulmonary Support: A Modeling Investigation.

Fontan patients often develop circulatory failure and are in desperate need of a therapeutic solution. A blood pump surgically placed in the cavopulmonary pathway can substitute the function of the absent sub-pulmonary ventricle by generating a mild pressure boost. However, there is currently no commercially available device designed for the cavopulmonary application; and the risks and benefits of implanting a ventricular assist device (VAD), originally designed for the left ventricular application, on the right circulation of failing Fontan patients is not yet clear. Moreover, further research is needed to compare the hemodynamics between the two clinically-considered surgical configurations for cavopulmonary assist, with Full and inferior vena cava (IVC) support corresponding to the entire venous return or only the inferior venous return, respectively, being routed through the VAD. In this study, we used a numerical model of the failing Fontan physiology to evaluate the Fontan hemodynamic response to a left VAD during the IVC and Full support scenarios. We observed that during Full support, the VAD improved the cardiac output while maintaining blood pressures within safe ranges, and lowered the IVC pressure to <15 mmHg; however, we found a potential risk of lung damage at higher pump speeds due to the excessive pulmonary pressure elevation. IVC support, on the other hand, did not benefit the hemodynamics in the patient cases simulated, resulting in the superior vena cava pressure increasing to an unsafe level of >20 mmHg. The findings in this study may be helpful to surgeons for recognizing the risks of a cavopulmonary VAD and developing coherent clinical strategies for the implementation of cavopulmonary support.

An alternative technique for completion of the total cavopulmonary connection.

Total Cavopulmonary connection (Fontan) is the final palliation for patients with a functionally univentricular heart. This is commonly accomplished after a prior bidirectional Glenn on cardiopulmonary bypass (CPB) with separate cannulation of the aorta, superior vena cava (SVC), and inferior vena cava. We describe an alternative technique of Fontan completion that eliminates the need for cannulation and dissection of the SVC, and pulmonary artery dissection. Between January and October 2018, 17 patients underwent completion Fontan using an alternate technique at our institute. All operations were conducted on CPB at normothermia without cannulating the SVC RESULTS: Mean CPB time was 60 ± 16.8 minutes (range, 39-102 minutes). There were no early deaths. Mean postoperative Fontan pressures were 15.6 ± 1.2 mm Hg with no gradient between the SVC and IVC pressures. Mean duration of hospital stay was 15.6 ± 3.6 days (range, 10-22 days). No patient developed phrenic nerve paresis or palsy. Completion without cannulating the SVC is simple, reproducible, and easy to teach. It avoids the disadvantages associated with routine techniques.