Superior Vena Cava Research Articles

Circulating Fetal Troponin I May Reflect Cardiomyocyte Proliferation

INTRODUCTION: Circulating biomarkers such as Troponin I (TnI) that are typically indicative of myocardial damage in adults have been reported to be detectable in cord blood of healthy infants delivered both vaginally and by cesarean section prior to labor. We performed serial sampling of healthy fetal sheep from ~20 days before spontaneous birth to 5 days postnatal in order to describe normal developmental values of circulating TnI. METHODS: Seven fetal sheep were surgically instrumented with indwelling catheters advanced into the ascending aorta and the superior vena cava. Following surgical recovery, daily blood samples were taken first thing in the morning into heparin, and the plasma was frozen for later determination of high-sensitivity (hs) TnI levels (BeckmanCoulter UniCel DxI Access IA; log transformed limit of detection =0.30, limit of quantification =0.78, and 99th%ile =1.78). Positive and negative control samples were drawn from an adult ewe during a terminal experimental ligation of the left anterior descending coronary artery and similarly assessed. hs-TnI data were log transformed from ng/L, visually assessed, and outliers removed by the ROUT method. RESULTS: Log(hs-TnI) was 1.47±0.30 at 20 days before birth and declined to 0.88±0.36 in fetuses 12±4 hour before birth (p<0.0001, R2=0.8444). Birth stimulated a delayed, transient peak in hs-TnI (P=0.0058). In the newborn, 43±19 min after birth, levels were 1.39±0.40 (P=0.0650 vs. fetus on day of birth). The day after birth, log(hs-TnI) increased to 2.14±0.63 (P=0.0331 vs. newborn). The second day after birth, levels declined to 1.65±0.48 (P=0.0238 vs. day 1). Adult ewe log(hs-TnI) was below the limit of detection; three hours following coronary artery ligation, levels were 3.21. CONCLUSIONS: This study confirms that hs-TnI levels are moderate to high in healthy sheep fetuses, and reports for the first time that they decline towards term. Why TnI is elevated in the healthy fetus is unknown. If cardiomyocyte TnI is leaked during cytokinesis, the decline towards birth may reflect the diminishing rate of proliferation in this same period. The postnatal hs-TnI peak, above the clinical threshold for evidence of myocardial ischemia in adult humans, may result from hemodynamic, oxidative, or metabolic stresses associated with the establishment of postnatal physiology. This work was funded by an award from the NHLBI (R01HL142483). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Impact of Breathing Control Training Program on sonographic quantification of abdominal vasculature.

To compare vascular scanning parameters (vessel diameter, peak systolic velocity, end-diastolic velocity, and resistive index) and scanning time before and after breathing control training program for selected abdominal vessels. This study was pre and post quasi-experimental. The researchers designed a breathing training program that gives participants instructions through a video describing breathing maneuvers. Data were collected at the ultrasound laboratory/College of Health and Rehabilitation Sciences in Princess Nourah bint Abdul Rahman University, Riyadh, Saudi Arabia from January 2023 to November 2023. About 49 volunteers at the university participated in the study. Scanning was performed two times for the right renal artery, upper abdominal aorta, inferior vena cava, and superior mesenteric artery. Scanning time was measured before and after the program as well. A paired sample t-test was used to compare the parameters means and time before and after the program. The program had a significant effect on the following parameters: right renal artery peak systolic velocity (p=0.042), upper abdominal aortic peak systolic velocity, and resistive index (p=0.014, p=0.014 respectively), superior mesenteric artery and inferior vena cava diameters (p=0.010 and p=0.020). The scanning time was reduced significantly (p<0.001). The breathing training program saves time and improves ultrasound measurement quality. Hospitals and health centers should consider the importance of breathing control training programs before abdominal scanning.

Preliminary report of a thoracic duct-to-pulmonary vein lymphovenous anastomosis in swine: A novel technique and potential treatment for lymphatic failure

ObjectiveThe thoracic duct is the largest lymphatic vessel in the body, and carries fluid and nutrients absorbed in abdominal organs to the central venous circulation. Thoracic duct obstruction can cause significant failure of the lymphatic circulation (i.e., protein-losing enteropathy, plastic bronchitis, etc.). Surgical anastomosis between the thoracic duct and central venous circulation has been used to treat thoracic duct obstruction but cannot provide lymphatic decompression in patients with superior vena cava obstruction or chronically elevated central venous pressures (e.g., right heart failure, single ventricle physiology, etc.). Therefore, this preclinical feasibility study sought to develop a novel and optimal surgical technique for creating a thoracic duct-to-pulmonary vein lymphovenous anastomosis (LVA) in swine that could remain patent and preserve unidirectional lymphatic fluid flow into the systemic venous circulation to provide therapeutic decompression of the lymphatic circulation even at high central venous pressures. MethodsA thoracic duct-to-pulmonary vein LVA was attempted in 10 piglets (median age 80 [IQR 80–83] days; weight 22.5 [IQR 21.4–26.8] kg). After a right thoracotomy, the thoracic duct was mobilized, transected, and anastomosed to the right inferior pulmonary vein. Animals were systemically anticoagulated on post-operative day 1. Lymphangiography was used to evaluate LVA patency up to post-operative day 7. ResultsA thoracic duct-to-pulmonary vein LVA was successfully completed in 8/10 (80.0%) piglets, of which 6/8 (75.0%) survived to the intended study endpoint without any complication (median 6 [IQR 4–7] days). Initially, 2/10 (20.0%) LVAs were aborted intraoperatively, and 2/10 (20.0%) animals were euthanized early due to post-operative complications. However, using an optimized surgical technique, the success rate for creating a thoracic duct-to-pulmonary vein LVA in six animals was 100%, all of which survived to their intended study endpoint without any complications (median 6 [IQR 4–7] days). LVAs remained patent for up to seven days. ConclusionA thoracic duct-to-pulmonary vein LVA can be completed safely and remain patent for at least one week with systemic anticoagulation, which provides an important proof-of-concept that this novel intervention could effectively offload the lymphatic circulation in patients with lymphatic failure and elevated central venous pressures.

Recanalization of right brachiocephalic vein for treatment of gastroesophageal reflux disease caused by superior vena cava syndrome

Recanalization of right brachiocephalic vein for treatment of gastroesophageal reflux disease caused by superior vena cava syndrome

Sternotomic resection of an anterior mediastinal cystic teratoma with pericardial fistula

Background: Mediastinal teratomas are rare tumors and the majority of them are mature teratomas, benign lesions characterized by slow growth and low malignant potential. Signs and symptoms are infrequent; hence the diagnosis is often incidental. Complicated cases are rare and are traditionally treated with elective surgery. Our case report presents a patient with a teratoma complicated by pericardial fistulization requiring emergency surgery: the only case described in the literature. Case presentation: A 36-year-old male with no relevant medical history reported acute thoracic pain. Chest CT scan shows a mediastinal mass (compatible with cystic teratoma) compressing the superior vena cava, the heart, and pericardial involvement. The patient was first subjected to pericardiocentesis and then an en-bloc resection of the mediastinal lesion was performed via sternotomy. Discussion and conclusion: Mediastinal lesions require an accurate differential diagnosis, despite the diagnosis often being incidental in the absence of clinical symptoms. Conversely, if symptomatic, complicated cases can lead to life-threatening situations, where the exeresis of such lesions might require urgent, complex, and multidisciplinary surgical intervention.

Extracorporeal membrane oxygenation (ECMO) assisted huge mediastinal tumor resection combined with superior vena cava replacement: A case report and literature review.

As to huge solid mediastinal tumor which direct compression or invasion of the superior/inferior vena cava (SVC/IVC), surgical resection remains the main lifesaving treatment. However, it would present formidable anesthetic challenges due to the extremely high risks of cardiorespiratory compromise, drastic hemodynamic fluctuations and death at all perioperative stages. Here, we report a case of huge anterior mediastinal tumor resection combined with SVC replacement under the assistance of venoarterial extracorporeal membrane oxygenation (VA ECMO), and stable hemodynamics were maintained as well as high internal jugular vein pressure being avoided during the operation procedure. He was weaned off ECMO successfully just after surgery and eventually discharged. No signs of postoperatively neurological complications occurred. Therefore, the use of ECMO assistance in huge mediastinal tumor resection combined with SVC replacement is feasible and safe, which may provide the possibility of surgical treatment for such patients and improve outcomes.

Syncope Due to Iatrogenic Cava Vein Obstruction: Rare Complication of Cardiac Implantable Electronic Device Leads

A 77-year-old female patient with multiple pacemaker leads experienced hypotension and syncope during right heart catheterization. Imaging studies revealed a stenotic inferior vena cava with superior vena cava obstruction and well-developed retrograde collateral vessels, suggesting that balloon obstruction of the sole venous return site caused low cardiac output leading to syncope.

Results of Palliative Stenting in Malignant Superior Vena Cava Syndrome Analyzing Self-Expanding Stainless Steel and Nitinol Venous Bare Metal Stents.

The purpose was to analyze the technical, clinical, and survival outcomes of our patients with malignant superior cava vein syndrome (SVCS) treated with endovascular approach and analyze the efficacy of different stent types used. It is an observational, retrospective, single-center study. From 2006 to 2023, 42 patients (32 male, 10 female, mean age 62 years, age range, 41-87 years) underwent percutaneous stent placement for malignant SVCS. One stainless steel stent (Wallstent) and 2 venous nitinol stent type (Sinus-XL, Venovo) were used. Follow-up mean was 276 days. A total of 53 stents were deployed. Clinical success was 97.6% in less 24 hours. Technical success was achieved in 97.6%. No complications were found except 1 patient died during the procedure due to stent migration and atrial dissociation (2.3%). Overall intraprocedural stent migration rate was 11.9% (18.8% stainless steel stent, 9.6% nitinol stent, p>0.05). Overall survival rates were 87.8%, 41.99%, and 34.12%, and overall primary patency rates were 100%, 93.3%, 91.6% at 1, 6, and 12 months, respectively. Endovascular treatment is a safe and effective therapeutic option for SVCS with high technical and clinical success rates and low complication and recurrence rates. The malignant superior cava vein syndrome is a rare clinical entity treated classically with radiation and chemotherapy with a slower response, or surgical bypass, which is an aggressive surgical technique. Endovascular treatment offers a low-invasive technique with quick clinical resolution and good permeability results. However, further studies are lacking to deal with procedure technical characteristics, stent type used, technical complications, and medium- and long-term patency studies. This study aims to evaluate all these items, analysing self-expanding stainless steel and nitinol venous bare metal stents, and add value to endovascular treatment, confirming the good results of this technique.

Safety and Effectiveness of Abre Self-Expanding Venous Stent for Treatment of Superior Vena Cava Syndrome.

Superior vena cava (SVC) syndrome is a constellation of symptoms that results from partial or complete SVC obstruction. Endovascular SVC stenting is an effective treatment for SVC syndrome with rapid clinical efficacy and low risk of complications. In this study, we assess the technical and clinical outcomes of a cohort of patients with SVC syndrome treated with the AbreTM self-expanding venous stent (Medtronic, Inc, Minneapolis, MN, USA). An institutional database was used to retrospectively identify patients with SVC syndrome treated with AbreTM venous self-expanding stent placement between 2021-2023. Patient demographic data, technical outcomes, treatment effectiveness, and adverse events were obtained from the electronic medical record. Nineteen patients (mean age 58.6) were included in the study. Thirteen interventions were performed for malignant compression of the SVC, 5 for central venous catheter-related SVC stenosis, and 1 for HD fistula-related SVC stenosis refractory to angioplasty. Primary patency was achieved in 93% of patients (17/19). Two patients (7%) required re-intervention with thrombolysis and angioplasty within 30days post-stenting. Mean duration of clinical and imaging follow-up were 228.7 ± 52.7 and 258.7 ± 62.1days, respectively. All patients with clinical follow-up experienced significant improvement in clinical symptoms post-intervention. No stent related complications were identified post-intervention. Treatment of SVC syndrome with the AbreTM self-expanding venous stent has high rates of technical and clinical success. No complications related to stent placement were identified in this study.

Prenatal Ultrasound Markers of Isolated Total Anomalous Pulmonary Venous Return and a Sequential Approach to Reach Diagnosis.

This article comprehensively reviews the literature concerning prenatal ultrasound findings of isolated total anomalous pulmonary venous return (TAPVR) and the application of specific sonographic markers to differentiate among the TAPVR types. These markers can be categorized as direct and indirect, based on either morphological features or hemodynamic changes in TAPVR. Indirect markers include the ventricular disproportion, an increased distance between the left atrium (LA) and the descending aorta, as well as the dilatation of superior vena cava or coronary sinus for supracardiac or cardiac TAPVR, along with abnormal pulmonary venous spectral Doppler patterns. Direct markers predominantly focus on the absence of a connection between the pulmonary veins and the LA. Some direct markers are specific to certain TAPVR types, such as the vertical vein. Diagnosing isolated TAPVR can pose challenges, but following a sequential approach can improve detection rates and outcomes. In cases with equivocal findings, additional follow-ups are recommended. The sequential approach described in the current article provides a step-wise methodology and sonographic markers for prenatal diagnosis of TAPVR, which can be utilized by fetal-maternal medicine specialists, obstetricians, and radiological technicians to ensure timely interventions.

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.

Superior Vena Cava Syndrome in Men with Thymic Atypical Carcinoid (Neuroendocrine Tumor Grade 2)

Introduction: Cases of neuroendocrine tumors (NET) can occur in various organs, generally in the form of gastroenteropancreatic (GEP-NET) and pulmonary tract (PNET). The incidence of thymic neuroendocrine tumors (TNET) is rare, accounting for less than 5% of thymic and mediastinal malignancies, and 0.4% of all neuroendocrine tumors. Case presentation: A 57-year-old man came to RSUP Dr. Mohammad Hoesin Palembang with complaints of coughing, bluish and curved blood vessels in the chest, and shortness of breath during activities that have been getting worse for six months. CT scan showed a tumor measuring 18.6 x 11.7 x 11 cm in the anterior mediastinum and pressing on the superior vena cava and abdominal aorta. TTNA and core biopsy with CT guidance showed NET Grade 2, mitoses 6/2 mm2, positive tumor cells with immunohistochemistry for synaptophysin, chromogranin, CD 56, AE1/AE3, and Ki67 9%. The patient received paclitaxel and carboplatin chemotherapy for 6 cycles. Conclusion: The prognosis for atypical carcinoid patients is 20-80% for a 5-year survival rate. Appropriate patient management is needed to improve the outcome of patients with primary thymic atypical carcinoid (NET, grade 2).

Delayed Diagnosis of Right Heart Failure Due to Sinus Venosus Atrial Septal Defect, Persistent Left Superior Vena Cava and Partial Anomalous Pulmonary Venous Return

Sinus venosus atrial septal defects (SVASD) are uncommon and often underdiagnosed as they are visualised poorly on transthoracic echocardiography (TTE). A 59-year-old man was referred following worsening dyspnoea. A TTE demonstrated dilated right chambers, with torrential tricuspid regurgitation and a dilated coronary sinus. Agitated saline test raised the suspicion of both persistent left superior vena cava (PLSVC) and an intracardiac shunt, despite interrogation of the interatrial septum not demonstrating any defects. CT imaging of the thorax was performed revealing a superior SVASD alongside a PLSVC, and partial anomalous pulmonary venous return. SVASD are considerably uncommon, compared to other types of atrial septal defects (ASD). TTE has poor sensitivity in diagnosing SVASD, highlighting the importance of multimodality imaging in such cases. The purpose of this case report is to highlight unique features demonstrated on TTE, especially during the agitated saline study, which showcased the presence of a PLSVC alongside an intracardiac shunt that was undetected through conventional TTE alone.

“A double twist” presentation – a case report of purulent cardiac tamponade following a rare complication of small-cell lung cancer radiotherapy

Background: Small cell lung cancer is an aggressive tumor with a poor prognosis that requires prompt treatment. While radiotherapy may enhance survival when superior vena cava syndrome is present, radiation therapy–induced pericardial disease can be a potential complication. Case Report: A 55-year-old man, who recently underwent radiotherapy for stage IV small-cell lung cancer complicated by superior vena cava syndrome, presented with chest pain and dyspnea. In the emergency room, he was dyspneic, hypotensive, and tachycardic. Pulmonary auscultation revealed the absence of lung sounds on the right. The initial electrocardiogram showed ST-segment elevation in lateral leads and in lead DII, with reciprocal changes in lead DIII. A bedside transthoracic echocardiogram revealed cardiac tamponade and emergent pericardiocentesis was performed, removing 500 ml of purulent fluid, resulting in an immediate clinical improvement. Thoracentesis was also performed, showing no empyema. Large spectrum empirical antibiotic therapy was started. Cultures from the pericardial fluid and peripheral blood grew multi-sensitive Streptococcus pneumoniae. Cytological analysis of the pericardial fluid was consistent with infection. The patient improved after 2 weeks of targeted antibiotic therapy and underwent the first cycle of chemotherapy. He was discharged with an early scheduled pulmonology appointment. Conclusions: Although the most common causes of pericardial effusion in lung cancer are malignant, non-malignant etiologies should also be considered. This patient had an infectious pericardial effusion most probably due to a pericardial-mediastinal mass fistula caused by radiotherapy. This was a diagnostic challenge, both in the emergency room as well in the inpatient setting.

Vein of Marshall Ethanol Infusion for AF Ablation; A Review.

The outcomes of persistent atrial fibrillation (AF) ablation are modest with various adjunctive strategies beyond pulmonary vein isolation (PVI) yielding largely disappointing results in randomised controlled trials. Linear ablation is a commonly employed adjunct strategy but is limited by difficulty in achieving durable bidirectional block, particularly at the mitral isthmus. Epicardial connections play a role in AF initiation and perpetuation. The ligament of Marshall has been implicated as a source of AF triggers and is known to harbour sympathetic and parasympathetic nerve fibres that contribute to AF perpetuation. Ethanol infusion into the Vein of Marshall, a remnant of the superior vena cava and key component of the ligament of Marshall, may eliminate these AF triggers and can facilitate the ease of obtaining durable mitral isthmus block. While early trials have demonstrated the potential of Vein of Marshall 'ethanolisation' to reduce arrhythmia recurrence after persistent AF ablation, further randomised trials are needed to fully determine the potential long-term outcome benefits afforded by this technique.

Body Size, Cerebral Blood Flow, Ambient Temperature, and Relative Brain Temperatures in Newborn Infants under Incubator Care.

Subtle changes in body temperature affect the outcomes of ill newborns. However, the temperature profile of neonatal brains remains largely unknown. In open-cot care, increased cerebral perfusion is correlated with higher superficial brain temperatures. This study investigated the dependence of brain temperature (relative to rectal temperature) on ambient temperature, body size, cerebral perfusion, and metabolism in infants receiving incubator care. Rectal, scalp, and brain temperatures, superior vena cava flow, and brain oxygenation were assessed using echocardiography, thermo-compensatory temperature monitoring, and near-infrared spectroscopy in 60 newborns. These infants had a mean postconceptional age of 36.9 (2.2) weeks and weighed 2348 (609) g at the time of evaluation. The ambient temperature was maintained at 30.0 (1.0) °C. A higher rectal temperature was associated with greater postconceptional age (p = 0.002), body weight (p < 0.001), and head circumference (p < 0.001). Relative scalp, superficial brain, and deep brain temperatures were associated with smaller head circumference (p < 0.001, p = 0.030, and p = 0.015, respectively) and superior vena cava flow (p = 0.002, p = 0.003, and p = 0.003, respectively). In infants receiving incubator care, larger head sizes and increased brain perfusion were associated with lower relative scalp and brain temperatures. When considered alongside previous reports, cerebral perfusion may contribute to maintaining stable cerebral tissue temperature against ambient temperature changes.

On the way to the azygos vein: a road of return rather than ruined

BackgroundThe malposition of central venous catheters (CVCs) may lead to vascular damage, perforation, and even mediastinal injury. The malposition of CVC from the right subclavian vein into the azygos vein is extremely rare. Here, we report a patient with CVC malposition into the azygos vein via the right subclavian vein. We conduct a comprehensive review of the anatomical structure of the azygos vein and the manifestations associated with azygos vein malposition. Additionally, we explore the resolution of repositioning the catheter into the superior vena cava by carefully withdrawing a specific length of the catheter.Case presentationA 79-year-old female presented to our department with symptoms of complete intestinal obstruction. A double-lumen CVC was inserted via the right subclavian vein to facilitate total parenteral nutrition. Due to the slow onset of sedative medications during surgery, the anesthetist erroneously believed that the CVC had penetrated the superior vena cava, leading to the premature removal of the CVC. Postoperative contrast-enhanced computed tomography of the chest confirmed that the central venous catheter had not penetrated the superior vena cava but malpositioned into the azygos vein. The patient was discharged 15 days after surgery without any complications.ConclusionsCVC malposition into the azygos vein is extremely rare. Clinical practitioners should be vigilant regarding this form of catheter misplacement. Ensuring the accurate positioning of the CVC before each infusion is crucial. Utilizing chest X-rays in both frontal and lateral views, as well as chest computed tomography, can aid in confirming the presence of catheter misplacement.

Illuminating the Genetic Basis of Congenital Heart Disease in Patients with Kabuki Syndrome.

Congenital heart defects (CHDs) affect a substantial proportion of patients with Kabuki syndrome. However, the prevalence and type of CHD and the genotype-phenotype correlations in Asian populations are not fully elucidated. This study performed a retrospective analysis of 23 Taiwanese patients with molecularly confirmed Kabuki syndrome. Twenty-two patients presented with pathogenic variants in the KMT2D gene. Comprehensive clinical assessments were performed. A literature review was conducted to summarize the spectrum of CHDs in patients with Kabuki syndrome. In total, 16 (73.9%) of 22 patients with pathogenic KMT2D variants had CHDs. The most common types of CHD were atrial septal defects (37.5%), ventricular septal defects (18.8%), coarctation of the aorta (18.8%), bicuspid aortic valve (12.5%), persistent left superior vena cava (12.5%), mitral valve prolapse (12.5%), mitral regurgitation (12.5%), and patent ductus arteriosus (12.5%). Other cardiac abnormalities were less common. Further, there were no clear genotype-phenotype correlations found. A literature review revealed similar patterns of CHDs, with a predominance of left-sided obstructive lesions and septal defects. In conclusion, the most common types of CHDs in Taiwanese patients with Kabuki syndrome who presented with KMT2D mutations are left-sided obstructive lesions and septal defects.

The impact of small movements with dual lumen cannulae during venovenous extracorporeal membrane oxygenation: A computational fluid dynamics analysis

Background and objectivesVenovenous Extracorporeal Membrane Oxygenation (VV ECMO) provides respiratory support to patients with severe lung disease failing conventional medical therapy. An essential component of the ECMO circuit are the cannulas, which drain and return blood into the body. Despite being anchored to the patient to prevent accidental removal, minor cannula movements are common during ECMO. The clinical and haemodynamic consequences of these small movements are currently unclear. This study investigated the risk of thrombosis and recirculation caused by small movements of a dual lumen cannula (DLC) in an adult using computational fluid dynamics. MethodsThe 3D model of an AVALON Elite DLC (27 Fr) and a patient-specific vena cava and right atrium were generated for an adult patient on ECMO. The baseline cannula position was generated where the return jet enters the tricuspid valve. Alternative cannula positions were obtained by shifting the cannula 5 and 15 mm towards inferior (IVC) and superior (SVC) vena cava, respectively. ECMO settings of 4 L/min blood flow and pulsatile flow at SVC and IVC were applied. Recirculation was defined as a scalar value indicating the infused oxygenated blood inside the drainage lumen, while thrombosis risk was evaluated by shear stress, stagnation volume, washout, and turbulent kinetic energy. ResultsRecirculation for all models was less than 3.1 %. DLC movements between -5 to 15 mm increased shear stress and turbulence kinetic energy up to 24.7 % and 11.8 %, respectively, compared to the baseline cannula position leading to a higher predicted thrombosis risk. All models obtained a complete washout after nine seconds except for when the cannula migrated 15 mm into the SVC, indicating persisting stasis and circulating zones. ConclusionIn conclusion, small DLC movements were not associated with an increased risk of recirculation. However, they may increase the risk of thrombosis due to increased shear rate, turbulence, and slower washout of blood. Developing effective cannula securement devices may reduce this risk.

Cardiac herniation post left upper lobectomy and thymectomy: a case report

BackgroundCardiac herniation occurs when there is a residual pericardial defect post thoracic surgery and is recognised as a rare but fatal complication. It confers a high mortality and requires immediate surgical correction upon recognition. We present a case of cardiac herniation occurring post thymectomy and left upper lobectomy.Case presentationInitial presentation: A 48-year-old male, hypertensive smoker presented with progressive breathlessness and was found to have a left upper zone mass confirmed on CT biopsy as carcinoid of unclear origin. PET-CT revealed avidity in a left anterior mediastinal area, left upper lobe (LUL) lung mass, mediastinal lymph nodes, and a right thymic satellite nodule. Intraoperatively: Access via left thoracotomy and sternotomy. The LUL tumour involved the left thymic lobe (LTL), left superior pulmonary vein (LSPV), left phrenic nerve and intervening mediastinal fat and pericardium, which were resected en-masse. The satellite nodule in the right thymic lobe (RTL) was adjacent to the junction between the left innominate vein and superior vena cava (SVC). The pericardium was resected from the SVC to the left atrial appendage. Clinical deterioration: Initially the patient was doing well clinically on day 1, however there was sudden bradycardia, hypotension, clamminess, and oligoanuria, with raised central venous pressures and troponins. ECG: no capture in leads V1-2, but positive deflections seen on posterior leads. Echo: no acoustic windows, but good windows seen posteriorly. CXR: left mediastinal shift. Redo operation: After initial resuscitation and stabilisation on the intensive care unit, on day 2 a redo-sternotomy revealed cardiac herniation into the left thoracic cavity with the left ventricular apex pointing towards the spine, and inferior caval kinking. After reduction and repair of the pericardial defect with a fenestrated GoreTex patch, the patient recovered well with complete resolution of the ECG and CXR.ConclusionCardiac herniation can even occur following sub-pneumonectomy lung resections and should be considered as a differential when faced with a sudden clinical deterioration, warranting early surgical correction.