Study of Multiple Systemic-to-Pulmonary Shunts in Single Ventricle Hearts

2012 ◽  
Author(s):  
Mahdi Esmaily Moghadam ◽  
Tain-Yen Hsia ◽  
Bari Murtuza ◽  
Alison Marsden
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Single Ventricle ◽  
Ductus Arteriosus ◽  
Adverse Outcomes ◽  
Flow Dynamics ◽  
Single Institution ◽  
Shunt Occlusion ◽  
Flow Competition ◽  
Blalock Taussig Shunt

For newborns diagnosed with single ventricle hearts and insufficient blood flow to the lungs, their lack of oxygen in the blood can be remedied with a modified Blalock-Taussig shunt (BTshunt) between the innominate and pulmonary artery. However, some surgeons prefer to have two systemic-to-pulmonary shunts, by either leaving the ductus arteriosus open or construct a second BT shunt, to provide additional pulmonary blood flow. There have been clinical reports of premature shunt occlusion when more than one shunt is employed, and a recent audit of shunt operations at a single institution has revealed increased mortality. There are speculation that these adverse outcomes can be due to flow competition between the two shunts, and/or having too much pulmonary blood flow. The flow dynamics and cardiopulmonary physiology in single ventricle circulations where pulmonary blood flow is supplied by more than one shunt has not been studied previously. In this study, we adopted CFD-based multi-domain simulations to compare a range of shunt configurations to examine the issue of flow competition and pulmonary overcirulation.

scholarly journals Simulations Reveal Adverse Hemodynamics in Patients With Multiple Systemic to Pulmonary Shunts

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Mahdi Esmaily-Moghadam ◽  
Bari Murtuza ◽  
Tain-Yen Hsia ◽  
Alison Marsden
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Thrombus Formation ◽  
Ductus Arteriosus ◽  
Pulmonary Atresia ◽  
Worst Case ◽  
Thrombotic Risk ◽  
Clinical Scenarios ◽  
Shunt Occlusion ◽  
Flow Competition

For newborns diagnosed with pulmonary atresia or severe pulmonary stenosis leading to insufficient pulmonary blood flow, cyanosis can be mitigated with placement of a modified Blalock–Taussig shunt (MBTS) between the innominate and pulmonary arteries. In some clinical scenarios, patients receive two systemic-to-pulmonary connections, either by leaving the patent ductus arteriosus (PDA) open or by adding an additional central shunt (CS) in conjunction with the MBTS. This practice has been motivated by the thinking that an additional source of pulmonary blood flow could beneficially increase pulmonary flow and provide the security of an alternate pathway in case of thrombosis. However, there have been clinical reports of premature shunt occlusion when more than one shunt is employed, leading to speculation that multiple shunts may in fact lead to unfavorable hemodynamics and increased mortality. In this study, we hypothesize that multiple shunts may lead to undesirable flow competition, resulting in increased residence time (RT) and elevated risk of thrombosis, as well as pulmonary overcirculation. Computational fluid dynamics-based multiscale simulations were performed to compare a range of shunt configurations and systematically quantify flow competition, pulmonary circulation, and other clinically relevant parameters. In total, 23 cases were evaluated by systematically changing the PDA/CS diameter, pulmonary vascular resistance (PVR), and MBTS position and compared by quantifying oxygen delivery (OD) to the systemic and coronary beds, wall shear stress (WSS), oscillatory shear index (OSI), WSS gradient (WSSG), and RT in the pulmonary artery (PA), and MBTS. Results showed that smaller PDA/CS diameters can lead to flow conditions consistent with increased thrombus formation due to flow competition in the PA, and larger PDA/CS diameters can lead to insufficient OD due to pulmonary hyperfusion. In the worst case scenario, it was found that multiple shunts can lead to a 160% increase in RT and a 10% decrease in OD. Based on the simulation results presented in this study, clinical outcomes for patients receiving multiple shunts should be critically investigated, as this practice appears to provide no benefit in terms of OD and may actually increase thrombotic risk.

scholarly journals Patent Ductus Arteriosus Stenting for All Ductal-Dependent Cyanotic Infants

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Kanishka Ratnayaka ◽  
Stephen J. Nageotte ◽  
John W. Moore ◽  
Peter W. Guyon ◽  
Krishna Bhandari ◽  
...  
Keyword(s):  
Blood Flow ◽  
Length Of Stay ◽  
Patent Ductus Arteriosus ◽  
Pulmonary Blood Flow ◽  
Ductus Arteriosus ◽  
Pulmonary Arteries ◽  
Practice Change ◽  
Almost All ◽  
Blalock Taussig Shunt ◽  
Patent Ductus

Background: Ductal-dependent cyanotic newborns require a secure source of pulmonary blood flow. There has been a recent migration to selective ductal (patent ductus arteriosus [PDA]) stenting for some of these children. Universal (nonselective) ductal stenting for all infants with ductal-dependent pulmonary blood flow is controversial. We examine outcomes from a single center with this practice change. Methods: We compare outcomes of all ductal-dependent pulmonary blood flow infants (2013–2020 [January–June]) in the following treatment eras: Era 1 (selective PDA stenting; 2013–2017) or Era 2 (universal PDA stenting; 2018–2020 [January–June]). Results: Eighty-eight patients (Blalock-Taussig shunt, n=41; PDA stent, n=47) met inclusion criteria. In Era 1, most received Blalock-Taussig shunt (62% [41/66]). In Era 2, all received PDA stents (100% [22/22]). There were more females in Era 2, but otherwise no demographic differences between eras. There were no differences in mortality, treatment failures, complications, or reinterventions between eras. Postprocedure length of stay was shorter in Era 2 (8 versus 22 days, P =0.02). There were less surgical revisions for PDA stent patients (2% versus 20%, P =0.02). Postprocedure recovery surrogate end points favored Era 2 and PDA stenting. Additional analysis revealed PDA stent (compared with Blalock-Taussig shunt) patients had shorter post-procedure (10 versus 29 days, P ≤0.001) length of stay and more symmetrical branch pulmonary arteries (0.9 versus 0.7, P =0.001) at subsequent surgery. Conclusions: PDA stenting for almost all ductal dependent cyanotic newborns can be safe and effective and may have lower morbidity than selective PDA stenting.

Results of Palliation With an Initial Modified Blalock-Taussig Shunt in Neonates With Single Ventricle Anomalies Associated With Restrictive Pulmonary Blood Flow

2015 ◽  
Vol 99 (5) ◽  
pp. 1639-1647 ◽  
Author(s):  
Bahaaldin Alsoufi ◽  
Scott Gillespie ◽  
Brian Kogon ◽  
Brian Schlosser ◽  
Ritu Sachdeva ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Single Ventricle ◽  
Blalock Taussig Shunt

THE ROLE OF THE PULMONARY VASCULAR BED IN CONGENITAL HEART DISEASE

PEDIATRICS ◽  
1953 ◽  
Vol 12 (3) ◽  
pp. 307-325
Author(s):  
J. FRANCIS DAMMANN ◽  
WILLIAM H. MULLER
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Single Ventricle ◽  
Ductus Arteriosus ◽  
Pulmonary Stenosis ◽  
Pulmonary Arteries ◽  
Signs And Symptoms ◽  
Pulmonary Resistance ◽  
Patient Will ◽  
Systemic Arteries

In the normal human being systemic blood pressure is maintained at a high level by means of the high resistance offered to the flow of blood by the smaller systemic arteries and arterioles. In contrast, pressure in the pulmonary circulation is maintained at a low level because of the relatively large size of the pulmonary vessels. In the fetal and newborn period pulmonary arteries resemble systemic arteries in that they have a small lumen and thick media. In this period pulmonary pressure and resistance are high. As these vessels gradually thin out and enlarge, resistance to pulmonary blood flow falls and consequently pulmonary blood pressure falls. There is evidence to suggest that the fetal state of thick-walled, thin-lumened pulmonary arteries is retained in instances where the two circulations are joined, such as in patients with a single ventricle, large ventricular defect, aortic septal defect or large patent ductus arteriosus. As the patient grows, resistance to pulmonary blood flow may: (1) decrease. If the small pulmonary arteries develop normally and become thin-walled and large-lumened, pulmonary resistance will fall. More and more blood will be shunted into the lungs and the patient will develop the signs and symptoms of cardiac decompensation. (2) remain the same. If the small pulmonary arteries retain their fetal characteristics, pulmonary resistance will remain elevated. A balance between systemic and pulmonary blood flow will be maintained compatible with a relatively normal life. (3) increase. If, because of secondary intimal changes, the pulmonary arteries become thicker-walled and smaller-lumened, pulmonary resistance will increase. Progressively less blood will be shunted to the lungs and finally the shunt will reverse and become predominantly venous arterial. The patient will develop the signs and symptoms of pulmonary stenosis with increasing dyspnea and cyanosis. Data from two groups of patients are presented to illustrate the importance of the pulmonary vascular bed. In the first group, early and severe symptoms of cardiac failure necessitated closure of a large patent ductus arteriosus early in life. The ductus was large, comparable to the size of the aorta, pressures from the aorta and pulmonary artery were similar and a study of the lung biopsies demonstrated that the lumens of the small pulmonary arteries were decreased in size and the media were abnormally thick. In each instance closure of the ductus resulted in a cure. In the second group the two circulations were joined by either a large ventricular defect or a single ventricle. Three patients were in cardiac failure due to excessive pulmonary blood flow. Pulmonary blood flow was decreased by the creation of pulmonary stenosis, the main pulmonary artery being narrowed 60 to 80%. The postoperative course in these three patients illustrates the value of the creation of pulmonary stenosis in instances where the two circulations are joined by a large communication between the ventricles or great vessels.

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