scholarly journals Investigation of a novel method for improving hemodynamics of Fontan circuit using an experimental model

2021 ◽  
Author(s):  
Suneet Bhansali ◽  
Tsusheel Kumar ◽  
Maya Crawford Crawford ◽  
Nikhil R. Katre
Keyword(s):  
Pressure Drop ◽  
Pulmonary Arteries ◽  
Initial Pressure ◽  
Fontan Circulation ◽  
Study Objective ◽  
Novel Device ◽  
Time Required ◽  
The Right ◽  
Physical Laws ◽  
Failing Fontan

Background: The study objective was to test underlying physical laws behind a proposed novel device for failing Fontan and investigate whether the device could be implemented theoretically to improve hemodynamics in failing Fontan circulation. Methods: A 4-arm setup was designed and fabricated to simulate an actual Fontan circuit in the form of a junction of the superior and inferior vena cavae (SVC, IVC) with the right and left pulmonary arteries (RPA, LPA). A provision for placement of an oscillating ball along the RPA-LPA path to push fluid away from SVC and IVC was created. The rate of ball oscillations and initial pressure of fluid on SVC and IVC limbs were varied. The pressure-drop times in the vena cavae limbs were measured at varying ball oscillations and resistances in the RPA-LPA pathway. The test was considered positive if increasing oscillations of the ball allowed for quicker pressure drop in the SVC and IVC limbs indicating quicker discharge of fluid through the RPA and LPA. 48 different experiments were conducted to simulate different physical conditions and the results were plotted and analyzed to draw a conclusion. Results: The time required for pressure drop in the experiment without ball was the least across all set of readings. This meant that placing an oscillating ball along the RPA -LPA path created obstruction to flow rather than enhance it. Increasing rate of ball oscillations increased degree of obstruction to flow. Conclusion: The proposed interventional method is unsuitable for improving hemodynamics in failing Fontan circulation.

Is the “Perfect Fontan” operation routinely achievable in the modern era?

2008 ◽  
Vol 18 (3) ◽  
pp. 328-336 ◽  
Author(s):  
James K. Kirklin ◽  
Robert N. Brown ◽  
Ayesha S. Bryant ◽  
David C. Naftel ◽  
Edward V. Colvin ◽  
...  
Keyword(s):  
Operative Procedure ◽  
Fontan Procedure ◽  
Fontan Operation ◽  
Pulmonary Arteries ◽  
Left Pulmonary Artery ◽  
Fontan Circulation ◽  
Caval Vein ◽  
Entire Cohort ◽  
Inferior Caval Vein ◽  
The Right

AbstractObjectiveIn 1990, Fontan, Kirklin, and colleagues published equations for survival after the so-called “Perfect Fontan” operation. After 1988, we evolved a protocol using an internal or external polytetraflouroethylene tube of 16 to 19 millimetres diameter placed from the inferior caval vein to either the right or left pulmonary artery along with a bidirectional cava-pulmonary connection. The objective of this study was to test the hypothesis that a “perfect” outcome is routinely achievable in the current era when using a standardized surgical procedure.MethodsBetween 1 January, 1988, and 12 December, 2005, 112 patients underwent the Fontan procedure using an internal or external polytetraflouroethylene tube plus a bidirectional cava-pulmonary connection, the latter usually having been constructed as a previous procedure. This constituted 45% of our overall experience in constructing the Fontan circulation between 1988 and 1996, and 96% of the experience between 1996 and 2005. Among all surviving patients, the median follow-up was 7.3 years. We calculated the expected survival for an optimal candidate, given from the initial equations, and compared this to our entire experience in constructing the Fontan circulation.ResultsAn internal tube was utilized in 61 patients, 97% of whom were operated prior to 1998, and an external tube in 51 patients, the latter accounting for 95% of all operations since 1999. At 1, 5, 10 and 15 years, survival of the entire cohort receiving polytetraflouroethylene tubes is superimposable on the curve calculated for a “perfect” outcome. Freedom from replacement or revision of the tube was 97% at 10 years.ConclusionUsing a standardized operative procedure, combining a bidirectional cavopulmonary connection with a polytetraflouroethylene tube placed from the inferior caval vein to the pulmonary arteries for nearly all patients with functionally univentricular hearts, early and late survival within the “perfect” outcome as predicted by the initial equations of Fontan and Kirklin is routinely achievable in the current era. The need for late revision or replacement of the tube is rare.

Platypnea-Orthodeoxia Syndrome in Fontan Circulation: Is It Gravity, the Height Difference Between the Right and Left Pulmonary Arteries, or Both?

2020 ◽  
Vol 36 (4) ◽  
pp. 590.e1-590.e2
Author(s):  
Yujiro Tajiri ◽  
Aya Miyazaki ◽  
Makoto Miyake ◽  
Ryo Higaki ◽  
Naoki Miki ◽  
...  
Keyword(s):  
Pulmonary Arteries ◽  
Fontan Circulation ◽  
Height Difference ◽  
The Right

Mechanical support of the functionally single ventricle

2006 ◽  
Vol 16 (S1) ◽  
pp. 55-60 ◽  
Author(s):  
Chitra Ravishankar ◽  
J. William Gaynor
Keyword(s):  
Extracorporeal Membrane Oxygenation ◽  
Single Ventricle ◽  
Pulmonary Arteries ◽  
Fontan Circulation ◽  
Ventricular Assist Devices ◽  
Mechanical Support ◽  
Membrane Oxygenation ◽  
Lateral Tunnel ◽  
Cavopulmonary Anastomosis ◽  
The Right

Children with a functionally single ventricle constitute just over 1% of congenital cardiac defects.1A majority of children with the functionally univentricular circulation undergo a three-staged reconstruction to achieve completion of the Fontan circulation. The first stage is usually performed in the neonatal period, and is either banding of the pulmonary trunk, an aorto-pulmonary shunt alone, or the shunt included as part of the first stage of reconstruction. In recent years, a conduit placed from the right ventricle to the pulmonary arteries is being used as an alternate source of flow of blood to the lungs. The second stage is the bidirectional cavopulmonary anastomosis, the two surgical variations being the so-called “hemifontan”, and “bidirectional Glenn” procedures, while the third stage is the completion of the Fontan circulation, the two surgical variations being either construction of a lateral tunnel, or placement of an extra-cardiac conduit, each being possible with or without a fenestration. In many centres, patients with the functionally univentricular circulation make up one-fifth of the total surgical volume. The syndrome of low cardiac output is quite common in this population through all three stages of reconstruction, and some of these patients will eventually require cardiac transplantation. While conventional therapy, with inotropic support and afterload reduction, remains the mainstay of therapy for the failing heart in children, mechanical support is being increasingly used.3Most of this experience is limited to extracorporeal membrane oxygenation.2–5In this review, we discuss the current experiences with extracorporeal membrane oxygenation in patients with a functionally univentricular circulation, and describes some of their unique features. We also focus on the pulsatile ventricular assist devices capable of providing support over the longer term, and other new devices that may have a role in the future in these patients.6

Measuring Earwax Cortisol Concentration Using a Non-Stressful Method (Preprint)

2020 ◽  
Author(s):  
Andrés Herane-Vives
Keyword(s):  
Cortisol Level ◽  
Local Stress ◽  
Extraction Methods ◽  
Cortisol Concentration ◽  
The Novel ◽  
Sampling Device ◽  
Related Factors ◽  
Novel Device ◽  
Cortisol Levels ◽  
The Right

BACKGROUND “Short-term” samples are not the most appropriate for reflecting Chronic Cortisol Concentration (CCC). Although hair is used for reflecting the systemic cortisol level over “long-term”, its use appears clinically problematic. Local stress and non-stress related factors may release a circumscribed cortisol secretion that is accumulated in hair. Non-stressful earwax extraction methods may provide a more accurate specimen to measure CCC. OBJECTIVE Correlate cortisol levels using hair, serum and earwax samples METHODS Earwax from both ears of 37 controls were extracted using a clinical procedure commonly associated with local pain. One month later, earwax from the left ear side was extracted using the same procedure, and earwax from the right ear side was comfortably extracted, using an earwax self-sampling device. Participants also provided one centimetre of hair that represented the retrospective month of cortisol output, and one serum sample that reflected the effect of systemic stressors on cortisol levels. Earwax (ECC), Hair (HCC) and Serum (SCC) Cortisol Concentration were correlated and compared. Confounders´ effect on cortisol levels were studied. RESULTS Serum showed the largest and hair the lowest cortisol concentration (p<0.01). Left-ECC was larger than Right-ECC (p=0.03). Right-ECC was the only sample unaffected by confounders (all p>0.05). Right-ECC and HCC showed the only significant association (r=0.39; p=0.03). CONCLUSIONS The self-sampling device did not represent a local stressor for the ceruminous glands. It provided the cortisol level with the least likely to be affected by confounding factors over the previous month. ECC using the novel device may constitute another accurate, but more suitable and affordable specimen for measuring CCC.

scholarly journals Anatomical correlation between left atrium pulmonary vein ablation targets of atrial fibrillation and adjacent bronchi and pulmonary arteries by MSCT

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yan-Jing Wang ◽  
Huan Sun ◽  
Xiao-Fei Fan ◽  
Meng-Chao Zhang ◽  
Ping Yang ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Pulmonary Vein ◽  
Pulmonary Arteries ◽  
Contact Points ◽  
Pulmonary Vein Ablation ◽  
Adjacent Structures ◽  
Anatomical Correlation ◽  
The Right

Abstract Background The ablation targets of atrial fibrillation (AF) are adjacent to bronchi and pulmonary arteries (PAs). We used computed tomography (CT) to evaluate the anatomical correlation between left atrium (LA)-pulmonary vein (PV) and adjacent structures. Methods Data were collected from 126 consecutive patients using coronary artery CT angiography. The LA roof was divided into three layers and nine points. The minimal spatial distances from the nine points and four PV orifices to the adjacent bronchi and PAs were measured. The distances from the PV orifices to the nearest contact points of the PVs, bronchi, and PAs were measured. Results The anterior points of the LA roof were farther to the bronchi than the middle or posterior points. The distances from the nine points to the PAs were shorter than those to the bronchi (5.19 ± 3.33 mm vs 8.62 ± 3.07 mm; P < .001). The bilateral superior PV orifices, especially the right superior PV orifices were closer to the PAs than the inferior PV orifices (left superior PV: 7.59 ± 4.14 mm; right superior PV: 4.43 ± 2.51 mm; left inferior PV: 24.74 ± 5.26 mm; right inferior PV: 22.33 ± 4.75 mm) (P < .001). Conclusions The right superior PV orifices were closer to the bronchi and PAs than other PV orifices. The ablation at the mid-posterior LA roof had a higher possibility to damage bronchi. CT is a feasible method to assess the anatomical adjacency in vivo, which might provide guidance for AF ablation.

Direct Measurement of Porto-systemic Gradient in a Failing Fontan Circulation

2011 ◽  
Vol 6 (2) ◽  
pp. 175-178 ◽  
Author(s):  
Madhavi Velpula ◽  
Nick Sheron ◽  
Neill Guha ◽  
Tony Salmon ◽  
Nigel Hacking ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Fontan Circulation ◽  
Failing Fontan

scholarly journals Ventilation/perfusion mismatch during lung aeration at birth

2014 ◽  
Vol 117 (5) ◽  
pp. 535-543 ◽  
Author(s):  
Justin A. R. Lang ◽  
James T. Pearson ◽  
Arjan B. te Pas ◽  
Megan J. Wallace ◽  
Melissa L. Siew ◽  
...  
Keyword(s):  
Pulmonary Arteries ◽  
Left Lung ◽  
X Ray ◽  
Lung Aeration ◽  
X Ray Imaging ◽  
Iodine Level ◽  
Pulmonary Shunting ◽  
Left And Right ◽  
Near Term ◽  
The Right

At birth, the transition to newborn life is triggered by lung aeration, which stimulates a large increase in pulmonary blood flow (PBF). Current theories predict that the increase in PBF is spatially related to ventilated lung regions as they aerate after birth. Using simultaneous phase-contrast X-ray imaging and angiography we investigated the spatial relationships between lung aeration and the increase in PBF after birth. Six near-term (30-day gestation) rabbits were delivered by caesarean section, intubated and an intravenous catheter inserted, before they were positioned for X-ray imaging. During imaging, iodine was injected before ventilation onset, after ventilation of the right lung only, and after ventilation of both lungs. Unilateral ventilation increased iodine levels entering both left and right pulmonary arteries (PAs) and significantly increased heart rate, iodine ejection per beat, diameters of both left and right PAs, and number of visible vessels in both lungs. Within the 6th intercostal space, the mean gray level (relative measure of iodine level) increased from 68.3 ± 11.6 and 70.3 ± 7.5%·s to 136.3 ± 22.6 and 136.3 ± 23.7%·s in the left and right PAs, respectively. No differences were observed between vessels in the left and right lungs, despite the left lung not initially being ventilated. The increase in PBF at birth is not spatially related to lung aeration allowing a large ventilation/perfusion mismatch, or pulmonary shunting, to occur in the partially aerated lung at birth.

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