#58 – Acyanotic Congenital Heart Defects



***LISTEN TO THE PODCAST HERE***



Click Here for Episode #11 – Review of Cyanotic Congenital Heart Defects



Review of In-Utero and Neonatal Cardiovascular Physiology

  • Ductus arteriosus
    • Connects the pulmonary artery to the descending aorta
    • Prostaglandin E2 are produced by the placenta and keep this open, along with low arterial oxygen concentration
    • Begins to close 10-15 hours after delivery and should be completed by 2-3 weeks of age
  • Foramen ovale
    • Communication between right and left atrium
    • Once the infant begins spontaneously breathing, increases in pulmonary blood flow and left atrial pressures mechanically seals the foramen ovale

Review of Initial Approach to Screening for Congenital Heart Diseases

  • The main approach to initial cardiac evaluation for infants with suspected heart disease is to determine:
    • Innocent vs Congenital Heart Disease
      • Cyanotic vs Acyanotic
      • Indications for emergent referral
  • Historical Clues
    • Symptomatic
      • Cyanosis, respiratory, poor growth, poor feeding, syncopal episodes
    • Family History
      • Parent or sibling with congenital heart disease
        • 1st degree relative with any CHD – RR 3.21
    • Genetic syndromes
    • Prenatal Evaluation
      • Abnormalities on prenatal ultrasound
      • Maternal factors that increase risk
        • Multifetal pregnancy, prematurity, preeclampsia, DM, HTN, Age > 40, alcohol/substance use, smoking,
    • Age of child
  • Physical Examination
    • Murmurs
      • Innocent murmur
        • ≤ Grade 2
        • Short systolic phase
        • Minimal radiation
        • Soft intensity
    • Extra Heart Sounds
      • Abnormal S2
      • S3 or S4
      • Systolic click
      • Thrills and heaves
    • Other Findings
      • Abnormal vital signs
        • BP differences between right arm, left arm, and legs
        • Weak or bounding pulses
      • Hepatomegaly
  • Diagnostic Studies
    • Pulse oximetry screening
      • Measure in right hand (pre-ductal) and either foot (post-ductal)
    • Chest radiograph
      • Cardiomegaly, increased pulmonary vascular markings, pulmonary edema
    • EKG
      • LVH, RVH, abnormal axis, dysrhythmias, prolonged QT
    • Echocardiogram
Up-to-Date. 2020

Ventricular Septal Defect

Epidemiology

  • 30% of all CHD (most common)

Normal Development

  • Three main components
    • AV canal septum (1)
    • Muscular septum (2)
    • Parietal band or distal conal septum (3)
  • Closure of the interventricular foramen is dependent on:
    • Right-sided endocardial cushions  projecting into the AV canal
    • Connective tissue growth on the crest of the muscular septum
    • Downward growth of ridges dividing the conus
Up-to-Date. 2020

Types

  • Membranous Defects
    • Most common clinically significant VSD
    • Under aortic valve and behind septal leaflet of the tricuspid valve
      • May extend into muscular septum
    • Can be associated with LVOTO and coarctation
  • Muscular Defects
    • Located along right ventricular free wall-septal junction, in the central muscular septum, or in the apical septum
    • Often close spontaneously
  • Malalignment Defects
    • Result from anterior/posterior malalignment of the conal septum
    • Associated with Tetralogy of Fallot
  • Subpulmonic Defects (outlet)
    • Superior and anterior conal septum defects
  • AV Canal Defects (inlet)
    • Posterior and superior to annulus of tricuspid valve
    • Associated with ASDs
Up-to-Date. 2020

Pathophysiology

  • Cause no problems in-utero
  • Causes a left-to-right shunt ex-utero
    • Higher left ventricular pressures
  • Categorization is based on:
    • Size
      • Small – < 4mm
      • Moderate – 4-6mm
      • Large – > 6mm
    • Shunt (Pulmonary:Systemic flow)
      • Small – Qp:Qs < 1.5
      • Moderate – Qp:Q 1.5-2.3
      • Large – Qp:Qs > 2.3
  • Effects on Circulation
    • Pulmonary
      • Increased and causes tachypnea and increased respiratory effort
    • Systemic
      • LV output must increase to maintain systemic flow
      • As systemic flow decreases (large VSDs):
        • Increased alpha-adrenergic stimulation
        • Increased catecholamine release
        • Increased angiotensin release
      • Increases risk of heart failure

Natural History

  • Small
    • 75% close spontaneously within 2 years of life
    • Those that persist in adulthood are benign
  • Moderate
    • Spontaneous closure depends on pulmonary arterial pressure and size/location of defect
    • Can respond to medical management
  • Large
    • Rarely spontaneously close
    • Surgery must be performed within 1st year to avoid permanent pulmonary vascular resistance

Clinical Presentation

  • Prenatal
    • Moderate to large VSD can be diagnosed during 20week ultrasound
  • Postnatal
    • Small VSD
      • Can be asymptomatic and present with only a murmur
    • Moderate to Large VSD
      • Present 3-4 weeks from birth with signs and symptoms of heart failure
        • Tachypnea
        • Poor feeding or poor weight gain
        • Tachycardia
        • Hepatomegaly
        • Rales, retractions
      • Cardiac Examination
        • Murmur
          • Harsh or blowing holosystolic
          • Heard best at 3rd-4th intercostal space
          • May have a diastolic rumble
            • Increased flow across mitral valve
          • Loud, splitting of S2
            • Due to increased pulmonary arterial pressure
        • Palpable thrill may be present

Diagnostic Studies

  • EKG
    • LVH, RVH, RAE
  • Chest Radiograph
    • Increased pulmonary vascular markings
  • Echocardiography
    • Two-dimensional Doppler confirms diagnosis
Radiopaedia

Management

  • Expectant
    • Most small VSD close spontaneously
    • Follow-up every 6 months with cardiologist until murmur resolves or yearly if murmur persists but still asymptomatic
  • Medical
    • Heart failure management
      • Diuretics are first line
    • Nutritional support
    • Pulmonary hypertension management
      • May need cardiac catheterization for accurate measurements and determination for surgical management
  • Surgical
    • Indications
      • Persistent symptoms with maximal medical therapy
      • Moderate/large defects with pulmonary hypertension
      • Persistent left-to-right shunt with LV dilation
      • Associated aortic valve prolapse or aortic regurgitation
      • Double-chambered right ventricle
    • Direct patch closure is procedure of choice in most children
    • Transcatheter closure is technically challenging and not offered routinely due to higher incidence of AV block and valve injury

Atrial Septal Defect

Epidemiology

  • 10-15% of all CHD
  • 1-2 per 1000 live births

Normal Development

  • Begins at 5th week and is made up of 3 structures
    • Septum primum and AV canal septum (endocardial cushions)
      • Arises from superior portion of common atrium
      • Grows caudally towards AV canal septum
        • These two fuse close ostium primum between right and left atria
    • Septum secundum
      • Covers the ostium secundum on the right atrial side of the septum primum
        • Forms the fossa ovalis
      • Leaves a small opening in-utero
        • Foramen ovale
          • Held open due to pressure gradients between the higher right atria and lower left atria
            • Allows for right to left flow
Up-to-Date. 2020

Types

  • Primum Defect
    • 15-20% of ASDs
    • Occurs when primum septum does not fuse with endocardial cushions
  • Secundum Defect
    • 70% of ASDs
    • 2x more common in females
    • Located within the fossa ovalis
  • Sinus Venosus Defect
    • 5-10% of ASDs
    • Malposition of the insertion of the superior or inferior vena cava on the atrial septum
  • Patent Foramen Ovale
    • Identified on 30% of adult autopsies
    • NOT considered an ASD because no septal tissue is missing
Up-to-Date. 2020

Natural History

  • Most close spontaneously
    • >80% of small (<5mm)
    • 30-60% of moderate (6-10mm)
    • Large (>10mm) do not close spontaneously
  • Persistent ASDs can cause pulmonary hypertension and heart failure in adulthood

Clinical Presentation

  • Most are asymptomatic and diagnosed only by identification of murmur
  • Murmur
    • Midsystolic pulmonary flow or ejection murmur
      • Heard best left 2nd intercostal space
    • Wide, fixed split S2
      • ASD equalizes the respiratory effect on both right and left ventricular output
      • If pulmonary hypertension is present, there may be an accentuated pulmonic component of S2
    • May have associated mitral regurgitation murmur

Diagnostic Studies

  • EKG
    • May show rSr’ or rsR’ pattern in V1
      • Incomplete RBBB
  • Echocardiogram
    • Transthoracic may see, but a transesophageal is better

Management

  • Often watch until child is 2yo as most will spontaneous
    • Even persistent defects are not recommended to close
  • Closure Indications
    • Right heart enlargement
    • Pulmonary overcirculation
    • Substantial left-to-right shunt
  • Types of Closures
    • Percutaneous
      • Criteria
        • < 30mm is diameter
        • ≥ 5mm or rim tissue around defect sufficient for effective closure without obstructing surrounding structures
      • Avoids bypass and major surgical incisions
      • Complications
        • Device embolization, malposition, dysrhythmias, cardiac perforation
    • Surgery
      • Indications
        • Sinus venosus defects
        • Coronary sinus defects
        • Primum ASDs
        • Large ASDs with heart failure
      • Closed with pericardial or Dacron patch

Atrioventricular Septal Defect

Epidemiology

  • 4-5% of CHD
  • 0.3-0.4 per 1000 live births
  • Up to a 50% risk of trisomy 21

Normal Development

  • Primitive AV canal connects the atria with the ventricles
  • At 4-5 weeks gestation, the superior and inferior endocardial cushions fuse and form the AV canal
    • This contributes to the AV valves and septum

Types and Classifications

  • Classified based on the degree of the defect
    • Complete
      • Complete failure of fusion between the superior and inferior endocardial cushions
        • Combined primum ASD and posterior VSD with a single, common AV valve
      • Can be balanced (both ventricles get same flow) or unbalanced (one gets more than the other)
        • Unbalanced can lead to hypoplasia
    • Partial
      • Incomplete fusion of superior and inferior endocardial cushions
        • Primum ASD, single AV valve annulus with 2 valve orifices
    • Transitional
      • Large primum defect, cleft mitral valve, and inlet VSD
Up-to-Date. 2020
  • Rastelli Classification
    • Type A
      • Most common form and most common ASVD with Down syndrome
    • Type B
      • Least common
    • Type C
      • Frequently found with other conditions
        • Tetralogy of Fallot, Transposition of Great Vessels
Up-to-Date. 2020

Pathophysiology

  • Complete AV Canal Defect
    • Increased pulmonary blood flow due to left-to-right shunting
      • Leads to heart failure and pulmonary hypertension
  • Partial AV Canal Defect
    • Volume overload of right atrium and right ventricle with pulmonary overcirculation due to left-to-right shunting
      • No pulmonary hypertension
    • Mitral regurgitation can be severe
  • Transitional AV Canal Defect
    • Shunting often mild due to small VSD

Clinical Presentation

  • In-Utero
    • Can be diagnosed early during pregnancy
    • Rarely cause any fetal distress or growth disturbances
  • Complete
    • Heart failure develops early in infancy
      • Tachypnea, poor feeding, poor growth, sweating, and pallor by 2 month
      • Severity of symptoms depends on size and degree of AV valve regurgitation
    • Physical examination
      • Hyperactive precordium with inferior/laterally displaced PMI
      • Increased S2
      • Systolic ejection murmur heard best at left upper sternal border
  • Partial and Transitional
    • Asymptomatic during childhood and only diagnosed on routine examination
    • Physical examination
      • Wide and fixed S2 during respiration
      • Systolic ejection murmur heard best at left upper sternal border
        • Diastolic rumble may be heard
        • Holosytolic murmur of MR

Diagnostic Studies

  • Echocardiography
    • Transthoracic is adequate
    • Apical four chamber or subcostal view is best to see defect

Management

  • In general, surgical correction is recommended because of significant morbidity and mortality of the pulmonary circulation effects
  • Complete
    • Correction by 6 months of age to prevent permanent pulmonary hypertension
    • Close the ASD and VSD and create to separate, competent AV valves
      • Single-patch or double-patch
Up-to-Date. 2020
  • Partial and Transitional
    • Primum ASD does not close spontaneously and leaves the patient at risk for atrial fibrillation and heart failure later in life
    • Surgical goal is to close intraatrial communication and restore/preserve AV valve competence
      • Patch closure of ostium primum defect and mitral valvuloplasty
    • Timing is usually between 18 months and 3 years

Patent Ductus Arteriosus

Epidemiology

  • 3-8 per 10,000 live births
  • 2:1 female predominance

Normal Development

  • Derived from the embryonic left sixth arch
  • Actually has different tissue than the aorta or pulmonary artery
    • Intima is thicker
    • Media contains more smooth muscle
  • In utero, allows from RV flow to placenta to get oxygenated
  • Keep open by low arterial oxygen and prostaglandin E2 from placenta
  • At birth, increased levels of arterial oxygen and the lack of prostaglandin E2 begins the process of spontaneous closure

Clinical Presentation

  • Symptoms depend on the degree of left-to-right shunting
    • Dependent on size and length of PDA, as well as the difference between the pulmonary and systemic vascular resistances
  • Classic murmur
    • Continuous, holosystolic murmur
      • Machinery murmur
    • Heard best over left upper sternal border
  • Small (Qp:Qs < 1.5 to 1)
    • Asymptomatic and detected on routine physical examination
  • Moderate (Qp:Qs 1.5-2.2 to 1)
    • May present with exercise intolerance and heart failure
      • Left-to-right shunt increasing left atrial and ventricular volume
        • Progress to left ventricular dilation and dysfunction
    • Displaced PMI
    • Widened pulse pressure
  • Large (Qp:Qs > 2.2 to 1)
    • Due to increased left sided pressures, can lead to increased pulmonary pressures
      • May be irreversible if not corrected
      • Can lead to right-to-left shunt if pressure is high enough
        • Eisenmenger syndrome (cyanosis)
      • Split S2 with prominent pulmonary component
      • Murmur may disappear as pulmonary pressure increases
    • Heart failure, poor feeding, failure to thrive, respiratory distress
    • Dynamic PMI with a thrill
    • Wide pulse pressures and bounding pulses

Diagnostic Studies

  • Transthoracic, doppler color flow echocardiography
    • The ductus is best viewed on the parasternal short-axis and suprasternal view

Management

  • Decisions are made on whether to actively close the PDA or monitor cardiac status
    • Term vs pre-term
      • Pre-term respond well to prostaglandin inhibitors
    • Size of the PDA
      • Moderate to large warrant closure
      • Small, audible PDA also benefit from closure to lower long term complications
        • Especially bacterial endocarditis
    • Degree of left-to-right shunt
    • Degree of left sided volume overload
    • Evidence of pulmonary hypertension
      • Closure not recommended in severe PAH
  • Closure Options
    • Medical/Pharmacologic Therapy
      • Prostaglandin inhibitors
        • Indomethacin, ibuprofen
          • Ibuprofen > indomethacin in term infants and older patients
    • Surgery
      • Posterolateral thoracotomy with direct PDA ligation
      • Video-Assisted Thoracoscopic Surgery (VATS) is less invasive option
        • Not indicated if PDA size > 9mm
      • Percutaneous closure using coils or commercial occlusion devices

Coarctation of the Aorta

Definition

  • Narrowing of the descending aorta at the insertion of the ductus arteriosus distal to the left subclavian artery

Epidemiology

  • 4-6% of all CHD
  • 4 cases per 10,000 live births
  • More common in males

Pathogenesis

  • Unknown, but two theories prevail:
    • Decreased intrauterine blood flow leading to under development of the fetal aortic arch
    • Migration/extension of ductal tissue into the wall of thoracic aorta
  • Genetic associations and increased familial risk
  • Usually accompanied with other CHD

Pathophysiology

  • As PDA and FO begin to close after birth, increased pressure over the narrowed aorta
    • Leads to left ventricular outflow tract obstruction
    • Increased collateral blood flow across the intercostals, internal mammary, and scapular vessels

Clinical Manifestations

  • Classic findings
    • Absent/delayed femoral pulses
    • Difference in upper extremity and lower extremity blood pressures
  • Neonates
    • Asymptomatic as long as there is a patent ductus
    • Murmurs of other CHD
  • Infants and Older Children
    • Complain of lower extremity claudication symptoms with exertion
    • Hypertension may be prominent
  • Adults
    • Hypertension is may sign
      • If severe, may lead to heart failure, aortic pathologies
    • Claudication can also be present

Diagnostic Studies

  • Chest radiography
    • Infants
      • Cardiomegaly with increased pulmonary vascular markings
    • Older children and adults
      • Rib notching from large collateral development
      • “3” sign from indentation of aortic wall at coarctation site
The red arrows point to rib notching caused by the dilated intercostal arteries. The yellow arrow points to the aortic knob, the blue arrow to the actual coarctation and the green arrow to the post-stenotic dilation of the descending aorta. Learning Radiology. 2020
  • Echocardiography
    • Transthoracic, doppler flow can visualize coarctation and evaluate for other defects
    • Ideal view is high parasternal long axis or suprasternal view
  • Cardiovascular MRI/CT
    • Recommended for adolescent and adult patients
  • Cardiac catheterization
    • Generally performed in conjunction with therapeutic interventions, or in adults with associated coronary disease

Management

  • Indications for inventions
    • Neonates with critical coarctation
      • Emergent medical therapy
        • Continuous infusion of prostaglandin E1
        • Inotropic support
        • Support care to correct metabolic derangements
    • Gradient > 20 mmHg
    • Radiologic evidence of clinically significant collateral flow
    • Hypertension or heart failure attributed to the defect
  • Types of Interventions
    • Balloon angioplasty (only)
      • Infants > 4 months and young children < 25kg
      • Preferred therapy for isolated coarctation
    • Stent Placement (after angioplasty)
      • Children > 25kg and adults
    • Surgical repair
      • Falling out of favor with increasing advancement and safety of transcatheter techniques



References

  1. Liu S, Joseph KS, Lisonkova S, et al. Association between maternal chronic conditions and congenital heart defects: a population-based cohort study. Circulation. 2013; 128(6):583-9. [pubmed]
  2. Jenkins KJ, Correa A, Feinstein JA, et al. Noninherited risk factors and congenital cardiovascular defects: current knowledge: a scientific statement from the American Heart Association Council on Cardiovascular Disease in the Young: endorsed by the American Academy of Pediatrics. Circulation. 2007; 115(23):2995-3014. [pubmed]
  3. Øyen N, Poulsen G, Boyd HA, Wohlfahrt J, Jensen PK, Melbye M. Recurrence of congenital heart defects in families. Circulation. 2009; 120(4):295-301. [pubmed]
  4. Frank JE, Jacobe KM. Evaluation and management of heart murmurs in children. American family physician. 2011; 84(7):793-800. [pubmed]
  5. Kang G, Xiao J, Wang Y, et al. Prevalence and clinical significance of cardiac murmurs in schoolchildren. Archives of disease in childhood. 2015; 100(11):1028-31. [pubmed]
  6. McCrindle BW, Shaffer KM, Kan JS, Zahka KG, Rowe SA, Kidd L. Cardinal clinical signs in the differentiation of heart murmurs in children. Archives of pediatrics & adolescent medicine. 1996; 150(2):169-74. [pubmed]
  7. van der Linde D, Konings EE, Slager MA, et al. Birth prevalence of congenital heart disease worldwide: a systematic review and meta-analysis. Journal of the American College of Cardiology. 2011; 58(21):2241-7. [pubmed]
  8. Hoffman JI, Kaplan S. The incidence of congenital heart disease. Journal of the American College of Cardiology. 2002; 39(12):1890-900. [pubmed]
  9. Zhao QM, Niu C, Liu F, Wu L, Ma XJ, Huang GY. Spontaneous Closure Rates of Ventricular Septal Defects (6,750 Consecutive Neonates). The American journal of cardiology. 2019; 124(4):613-617. [pubmed]
  10. Zhang J, Ko JM, Guileyardo JM, Roberts WC. A review of spontaneous closure of ventricular septal defect. Proceedings (Baylor University. Medical Center). 2015; 28(4):516-20. [pubmed]
  11. Bol-Raap G, Weerheim J, Kappetein AP, Witsenburg M, Bogers AJ. Follow-up after surgical closure of congenital ventricular septal defect. European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. 2003; 24(4):511-5. [pubmed]
  12. Butera G, Carminati M, Chessa M, et al. Transcatheter closure of perimembranous ventricular septal defects: early and long-term results. Journal of the American College of Cardiology. 2007; 50(12):1189-95. [pubmed]
  13. Hanslik A, Pospisil U, Salzer-Muhar U, Greber-Platzer S, Male C. Predictors of spontaneous closure of isolated secundum atrial septal defect in children: a longitudinal study. Pediatrics. 2006; 118(4):1560-5. [pubmed]
  14. Muta H, Akagi T, Egami K, et al. Incidence and clinical features of asymptomatic atrial septal defect in school children diagnosed by heart disease screening. Circulation journal : official journal of the Japanese Circulation Society. 2003; 67(2):112-5. [pubmed]
  15. Korenberg JR, Bradley C, Disteche CM. Down syndrome: molecular mapping of the congenital heart disease and duodenal stenosis. American journal of human genetics. 1992; 50(2):294-302. [pubmed]
  16. Cetta F, Minich LL, Edwards WD, et al. Atrioventricular septal defects. In: Moss and Adams’ Heart Disease in Infants, Children, and Adolescents Including the Fetus and Young Adult, 7th ed, Allen HD, Shaddy RE, Driscoll DJ, Feltes TF (Eds), Lippincott Williams & Wilkins, Philadelphia 2007.
  17. Rastelli G, Kirklin JW, Titus JL. Anatomic observations on complete form of persistent common atrioventricular canal with special reference to atrioventricular valves. Mayo Clinic proceedings. 1966; 41(5):296-308. [pubmed]
  18. Backer CL, Stewart RD, Mavroudis C. What is the best technique for repair of complete atrioventricular canal? Seminars in thoracic and cardiovascular surgery. 2007; 19(3):249-57. [pubmed]
  19. Minich LL, Atz AM, Colan SD, et al. Partial and transitional atrioventricular septal defect outcomes. The Annals of thoracic surgery. 2010; 89(2):530-6. [pubmed]
  20. Hoffman JI, Kaplan S. The incidence of congenital heart disease. Journal of the American College of Cardiology. 2002; 39(12):1890-900. [pubmed]
  21. Warnes CA, Williams RG, Bashore TM, et al. ACC/AHA 2008 Guidelines for the Management of Adults with Congenital Heart Disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to develop guidelines on the management of adults with congenital heart disease). Circulation. 2008; 118(23):e714-833. [pubmed]
  22. Giroud JM, Jacobs JP. Evolution of strategies for management of the patent arterial duct. Cardiology in the young. 2007; 17 Suppl 2:68-74. [pubmed]
  23. Keane JF, Flyer DC. Coarctation of the aorta. In: Nadas’ Pediatric Cardiology, 2nd ed, Keane JF, Lock JE, Fyler DC (Eds), Saunders Elsevier, Philadelphia 2006.
  24. Beekman RH III. Coarctation of the Aorta. In: Moss and Adams’ Heart Disease in Infants, Children, and Adolescents, 6th ed, Allen HD, Driscoll DJ, Shaddy RE, Feltes TF (Eds), WK Lippincott Willams and Wilkins, Philadelphia 2008. Vol 2
  25. Silversides CK, Kiess M, Beauchesne L, et al. Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: outflow tract obstruction, coarctation of the aorta, tetralogy of Fallot, Ebstein anomaly and Marfan’s syndrome. The Canadian journal of cardiology. 2010; 26(3):e80-97. [pubmed]
  26. Baumgartner H, Bonhoeffer P, De Groot NM, et al. ESC Guidelines for the management of grown-up congenital heart disease (new version 2010). European heart journal. 2010; 31(23):2915-57. [pubmed]

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s