Presentation on theme: "Kendra Marsh, MD Division of Cardiology, UIC Fellow"— Presentation transcript:
1 Kendra Marsh, MD Division of Cardiology, UIC Fellow Atrial Septal DefectKendra Marsh, MDDivision of Cardiology, UICFellow
2 Embryology Gestational Week 4 Gestational Week 4-6 • A thin, crescent shaped wedge of tissue of (septum primum) grows towards and fuses with endocardial cushions.The remaining opening is called the ostuim primum. •As the septum primum is growing down, the endocardial cushions fuse and the ostium primum is eventually obliterated.
3 EmbryologyThe interatrial septum forms during the first and second months of fetal development.Stage I is the formation of the septum primum.The septum primum walls off a crescent-shaped portion of the hole between the right and left atria.Foramen primum (also called the ostium primum) stays openThe remaining part of the opening between the right and left atria is closed by the septum secundum.The 2 tissue layers overlap like a flap, allowing blood flow to continue during fetal life.Changes in circulation at birth, closes the flap permanently.
4 Anatomy and Physiology Extends from cavo-atrial junction with superior and inferior vena cavaeEnds near the atrio-ventricular canal near the tricuspid valve
5 Ostium Secundum Most common type of ASD Center of the septum between the right and left atriumVariant of this type of ASD is called a Patent Foramen Ovale (PFO) which is very small.
6 Ostium Primum Next most common type Located in the lower portion of the atrial septum.Will often have a mitral valve defect associated with it called a mitral valve cleft.A mitral valve cleft is a slit-like or elongated hole usually involves the anterior leaflet of the mitral valve.
7 Sinus Venosus Least common type of ASD Located in the upper portion of the atrial septum.Association with an abnormal pulmonary vein connectionFour pulmonary veins, two from the right lung and two from the left lung, normally return red blood to the left atrium.Usually with a sinus venosus ASD, a pulmonary vein from the right lung will be abnormally connected to the right atrium instead of the left atrium.This is called an anomalous pulmonary vein...\asd-veno.jpg
8 Foramen Ovale Remnant of fetal circulation Behaves like flap valve Opens during increased intra-thoracic pressure
9 Incidence and Prevalence one of the most common congenital heart defects seen in pediatric cardiology7-10% of all patients with congenital heart diseaseTwice as frequent in females than males
11 Diagnostics ECG X-RAY ECHOCARDIOGRAPHY Sometimes cardiac catheterization
12 Shunt Determination Normally… Shunt Suspected If… Types of Shunts Pulmonary Blood Flow = Systemic Blood FlowShunt Suspected If…Pulmonary Artery Saturation >80% (?Left-Right)Unexplained Arterial Saturation less than 93%(Right to Left)may also see in Pulmonary Edema, Pulmonary Disease, over sedation and cardiogenic shockTypes of ShuntsSystemic Circulation to Pulmonary CirculationLeft to rightPulmonary Circulation to Systemic CirculationRight to Left
13 Invasive Methods to Diagnose Shunting Oximetric MethodIndicator Dilution Method
14 Principles of the Oxymetric Method Blood Sampling from various chambers to determine Oxygen SaturationLeft to Right Shunt is present when a significant increase in blood oxygen saturation is found between 2 right sided vessels or chambers
15 Oximetric Method“Shunt Run” is performed if a difference of 8% or more is noted in blood sampling between chambersBlood samples taken from all right sided locations: IVC, SVC, Right Atrium, Right Ventricle and Pulmonary ArteryIn case of Inter-atrial shunt multiple samples should be collected from the High, middle and low right atrium
16 Saturation Run Obtain Samples from… IVC: High and LowSVC: High and LowRight Atrium: High, Middle and LowRight Ventricle: Inflow and Outflow tracts, mid-cavityPulmonary Artery: Main, Left or RightLocalizing Right to Left Shunts one should also obtain….Pulmonary VeinLeft AtriumLeft VentricleDistal Aorta
17 Fick Equation to Calculate Oxygen Content Assumes in steady state that…that rate of substance entering (C in x Qflow) is equal to the rate of substance leaving(C out x Qflow) + the rate at which indicator, V, is added.Flow= Oxygen consumption/Arterial-Venous oxygen content differenceWhere oxygen content is determined by automated methodsoxygen consumption is assumed based on patient’s age, gender and body surface area when not directly measured
18 Shunt Quantification Pulmonary Blood Flow Systemic Blood Flow Oxygen consumption_________________________________________Difference in oxygen content across pulmonary bed(PvO2-PaO2)Systemic Blood FlowOxygen ConsumptionDifference in oxygen content across systemic bed(SaO2- MvO2)Effective Blood Flow: Fraction of Mixed Venous blood received by the lungs without contamination from shunt__________________(PvO2-MvO2)
19 Flamm Formula Average Oxygen Content in Chambers proximal to the Shunt Method to calculate Mixed Venous Oxygen contentNeed to factor in Contribution from IVC and SVC which is not equalFlamm Equation:3xSVC Oxygen Content + IVC Oxygen Content______________________________________4
21 How Significant is the Shunt? Flow Ratio PBF/SBF2.0 or more = Large Left to Right Shunt1.0 or less= Net Right to left ShuntNo need to measure Oxygen consumptionSince this number will cancel out of the equation
22 Indicator Dilution Method More Sensitive for smaller shuntsCannot localize the level of left to right shuntLeft to Right : Dye (indocyanine green) is injected into pulmonary artery and a sample is taken from the systemic arteryRight to Left: dye injected just proximal to the presumed shunt and blood sample is taken from systemic artery
24 Eisenmenger Syndrome defect in the septum between the atria increased flow through the lungs after birth.eventually result in pulmonary hypertension.The first indication of this may be a reduction in heart sizeflow overload is converted to a pressure overload ( to which the heart responds with hypertrophy, rather than dilatation ). Reduction in heart-size,As the left-to-right shunt is converted by reversal of flow across the septum to right-to-left shunt, the patient becomes cyanotic from mixing of un-oxygenated blood.Cyanosis is thus a late feature of Atrial Septal defect.If cyanosis is present from birth, ASD will be complicated by one or more contributions:Pulmonary Stenosis.Patent Ductus, usually causes a very large pulmonary artery and enlargement of the aorta.Common Atrium, allowing complete mixing of oxygenated and unoxygenated blood.Truncus arteriosus, complete mixing at aortic level.
25 Pregnancy and ASD Well tolerated after closure Increased risk of paradoxical emboli peri and post partumContraindicated in Eisenmenger SyndromeMaternal mortality 50%Fetal Mortality 60%
26 TTE and ASDTransthoracic echocardiogram four chamber view to evaluate atrial septal defect. Note presence of inter-atrial communication between left and right atrium.
27 Indications for Intervention Asymptomatic ChildrenRight Heart dilationASD> 5mmNo signs of Spontaneous ClosureOlder PatientsHemodynamically insignificant ASD with Qp/Qs<1.5 if concern for strokePulmonary HypertensionPA pressures> 2/3 systemic arterial resistancePulmonary artery reactivity with vasodilator challengeReversible changes on lung biopsyNet L->R Shunt of 1.5:1
28 Treatment Options1976, King et al published the first attempt to close an ASD with a double umbrella deviceSize of the sheath was 23 FrPrimary Method of to date for closure is surgicalRecent advances in interventional closure techniques
29 Trans-catheter Closure Technique Implantation of one or more devices via catheter methodEliminates need for cardio-pulmonary bypassNo need to stop the heart with cardioplegic agents
30 Patient Selection Strict Food and Drug Administration guidelines Efficacy measured using data from strict follow upFollow-up at regular intervals- 3, 6, and 12 months the year following the initial procedureAny adverse events require follow up for 5-7 years
31 Patient Selection Defects smaller than 20-25mm in diameter Should not have defects in the very upper or lower portions of the septumOstium Primum or Sinus Venosus, not good candidates because defect usually involves heart valves or abnormal venous drainage from the lungsOnly benefit Ostium Secundum defectsNo lower age limit, but must weigh more than 8-10 kg
32 Trans-catheter Approach Device is advance through an introducer sheathOne- Half of the device is deployed on left side of atrial septum, the second half is deployed on the right sideA “sandwich” is formed over the defect6-8 weeks, device as a frame work for scar tissue to formIn children the new tissue formation with continue to grow
33 TTE post InterventionTransesophageal echocardiogram showing Amplatzer device placed across the defect forming a “sandwich” over the atrial septal defect
34 TTE after intervention Transthoracic echocardiogram four chamber view one day after Amplatzer device placement
35 Complete resolution of shunt Transthoracic echocardiogram one day after Amplatzer device placed with highlighted area that shows no further shunting of blood across atrial septum.
36 Tissue formation over Helex device in canine model In vivo tissue response demonstrating flat profile, conformance to the septum, and nonthrombogenic Occluder material; top photo shows left atrial view; bottom photo shows right atrial side view.
38 Amplitizer Atrial Septal Defect Occluder AGA Medical, Golden Valley Mn2001- FDA approved for Secundum lesionsNitinol mesh frame work and left/right atrial disksFilled with poly-fabric to promote thrombosusCost $11K, Surgery$ 21K
39 Helex atrial septal defect device. W.L. Gore & AssociatesJuly 1999Nitinol, nickel/titanium alloyWire frame in shape of coil with Gore-Tex9 Fr introducer sheathCost: $6000
40 Helex Septal Occluder Delivery System components
42 Outcomes Amplatzer study 100 children and adults Mean age 13.393 patients successful implantationOcclusion rate at 3 months total occlusionImprove RV and LV function and decreased LA volumesPercutaneous Closure and Functional Capacity32 adults mean age 43 yoQp/Qs 2.0+6 months-improved O2 uptake with exercise as compared pre-closure status
43 Comparison to Surgery Study of children and young adults Median age 9.8 y442 underwent Amplatzer placement154 underwent surgerySuccess rate 100% surgery, 96 % AmplatzerComplication 7% Amplatzer, 24 % surgery
44 Complication of Percutaneous Intervention EarlyDevice EmbolizationA. Fib, SVTHeart BlockPericardial EffusionGroin HematomaDevice FracturesCardiac PerforationDevice ErosionSudden Death
45 Participation in sports th Bethesda Conference on Eligibility Recommendations for Competitive Athletes with Cardiovascular Abnormalities…Small defect no Pulmonary HTNpartcipate in all sportsLarge Defect, normal PA pressuresall competative sportsModerate to large ASD and Pulmonary HTN sever-no competative sportsASD and mild Pulmonary HTNLow intensisty sports
46 Follow Up 3-6 months post intervention May participate in sports if no Pulm HTN, Heart Block, or Myocardial DysfunctionExercise evaluation if these conditions existAmerican Heart Association, no endocarditis prophylaxis post corrrection of ASD unless patient has MR or MV malformation
47 Follow UpAspirin and Plavix 6 months post percutaneous closure