Day: August 17, 2020

What Are the Main Acyanotic Congenital Heart Diseases?

Patient Presentation
An 8-year-old male was referred to the nephrology clinic of a regional children’s hospital for hypertension. The patient had been seen at a mobile free medical clinic and was noted to have an elevated blood pressure when taken several times with measurements in the 140s-150s systolic and 100-110s diastolic. The past medical history showed he had little medical care previously because he was relatively well per his parents, and he was partially vaccinated. The family history was negative for cardiac or renal disease. There was diabetes and possibly a stroke in two paternal family members. The social history revealed a pleasant immigrant family with limited educational and economic resources. The review of systems found no frequent infections, dyspnea, fatigue, lethargy, facial or extremity swelling, cyanosis, or failure to thrive (although the physicians suspected food insecurity). The patient did complain of intermittent headache but the family could not provide additional details.

The pertinent physical exam showed a thin male with height and weight in the 10%. Parents were also small individuals. Blood pressure was 158/112 in right upper extremity, 134/98 in left upper extremity, 138/104 in right lower extremity, and 128/96 in left lower extremity. HEENT was normal but it was difficult to see the optic discs. His cardiac examination had no murmurs, bruits or jugulovenous distension. His abdominal examination had no masses or hepatosplenomegaly. There was no peripheral edema.

The diagnosis of hypertension with abnormal four-point blood pressures made the diagnosis of coarctation of the aorta a strong possibility. The laboratory evaluation with normal urinalysis, electrolytes and full chemistry panel and thyroid studies was eventually normal. The nephrologist consulted the cardiologists who saw him that afternoon. Echocardiogram confirmed coarctation of the aorta. The patient was started on antihypertensive medication and was taken to the interventional cardiology suite 3 days later for angiography and balloon dilatation. He was followed for the next three months and was weaning down on the hypertensive medication. He missed his next appointment and the clinic social worker was told by his school that the family had moved out of the area.

Discussion
Congenital heart diseases (CHD) are malformations of the heart and great vessels. It occurs in about 5-8/1000 live births. Cyanotic congenital heart disease is often noted perinatally because of cyanosis, respiratory distress and/or poor feeding or other distress type problems. A review can be found here.

Acyanotic congenital heart disease (ACHD) can present at birth but often is seen in older children or adults unless the lesions are severe, especially obstructive lesions. Severe lesions may also cause cyanosis and distress type problems in patients also.

  • Shunting lesions cause problems by diverting blood flow into an abnormal location with frequent overflow of blood in that area.
    • Atrial septal defects (ASD)
      • Defect in the atrial septum. Occurs in 8-12% of CHD.
      • There are 4 types: ostium primum, ostium secundum, sinus venosus and coronary sinus.
      • Blood is shunted from left to right with right sided volume overload which causes dilatation of right sided structures.
      • Clinical
        • Patients are often asymptomatic with incidental murmur.
        • Murmur – Normal S1, fixed split S2, systolic ejection murmur in pulmonic area.
      • Evaluation
        • Electrocardiogram can show right bundle branch block with right atrial enlargement.
        • Chest radiograph shows cardiomegaly with pulmonary artery dilatation and increased pulmonary vascular markings.
      • Treatment – They can spontaneous close but this is not common after age 2 or if defect is > 8 mm. Small ones can be closed with devices. Larger ones may need percutaneous or cardiac surgery.
    • Ventricular septal defects (VSD)
      • Defect in the ventricular septum. Occurs in 8-12% of CHD.
      • Types are perimembraneous, muscular, inlet or outlet. Perimembraneous and muscular may spontaneous close.
      • Blood is shunted from left to right with right sided volume overload which causes dilatation of right sided structures.
      • Clinical
        • Patients are often asymptomatic with incidental murmur, but can have failure to thrive, congestive heart failure, recurrent pulmonary infections, or Eisenmenger syndrome.
        • Murmur – Normal S1, normal S2, harsh pansystolic murmur at lower left sternal border. Mid-diastolic murmur may also be heard.
        • Evaluation
          • Electrocardiogram can be normal or show left ventricular hypertrophy.
          • Chest radiograph shows cardiomegaly with pulmonary artery dilatation and increased pulmonary vascular markings.
        • Treatment – Perimembraneous and muscular may spontaneous close. Small ones can be closed with devices. Larger ones may need percutaneous or cardiac surgery.
    • Patent ductus arteriosis (PDA)
      • The ductus arteriosus (DA) connects the aorta to pulmonary artery during fetal life effectively shunt fetal circulation away from the lungs. It usually closes after birth by 24 hours of life and becomes a fibrous remnant.
      • If closure fails then a PDA is the result. The DA is purposely kept open in some cases of CHD to maintain circulation. Examples would be pulmonary stenosis, tetrology of fallot, tricuspid atresia or transposition of the great veins.
      • It is a left to right sided shunt
      • Clinical
        • Patients may be asymptomatic or have recurrent respiratory infections, congestive heart failure or failure to thrive.
        • Murmur – Normal S1, normal S2, with a continuous murmur in left upper sternal border. A loud P2 may be also heard.
        • Evaluation
          • Electrocardiogram is normal or has left ventricular hypertrophy.
          • Chest radiograph shows cardiomegaly with pulmonary artery dilatation, aorta that is prominent and increased pulmonary vascularity.
        • Treatment – device closure or surgical treatment.
  • Obstructive lesions impair the blood flow through the heart and great vessels. Hypertrophy is seen proximal to the lesion and dilatation is seen distal to it.
    • Right ventricular outflow tract obstruction (RVOT)
      • Occurs in pulmonary arteries and its branches. Occurs at the valvular, or sub- or supra-valvular areas.
      • Valvular pulmonic stenosis is the most common type of RVOT (7-9% of all CHD).
      • Clinical
        • Mild to moderate obstruction often is asymptomatic with an incidentally noted murmur. Severe probably will be cyanotic.
        • Right heart failure may be seen such as hepatomegaly or pedal edema.
        • Murmur – Normal S1, S2 may be wide split with decreased P2 intensity. Systolic ejection murmur present at left upper sternal border with radiation to the back.
        • Longer duration or increased intensity murmurs may indicate more severe stenosis.
        • Evaluation
          • Electrocardiogram shows right ventricular hypertrophy with monophasic R waves in precordial leads.
          • Chest radiograph shows normal cardiac silhouette but with dilated pulmonic artery.
        • Treatment – balloon dilatation with surgery.
    • Left ventricular outflow tract obstruction (LVOT)
      • Occurs in aorta and its branches. Occurs at the valvular, or sub- or supra-valvular areas. Ventricular septal defect is a common accompanying lesion.
      • Valvular aortic stenosis is the most common type of LVOT (5-6% of all CHD). Valvular aortic stenosis most commonly occurs in bicuspid aortic stenosis.
      • Clinical
        • Mild to moderate obstruction often is asymptomatic. Severe stenosis may have cyanosis and/or heart failure in neonates. Older children and adults may have dyspnea, chest pain and/or presyncope or syncope.
        • Murmur – Normal S1, Normal S2 may have paradoxically split S2 when severe. Systolic ejection murmur and click present at the right upper sternal border with radiation to the back.
        • Longer duration or increased intensity murmurs may indicate more severe stenosis.
        • Evaluation
          • Electrocardiogram shows left ventricular hypertrophy with T wave inversion in lateral leads.
        • Treatment – percutaneous valvuloplasty or surgical valvuloplasty.

    Learning Point
    Coarctation of the aorta(CoA) is a congenital (present at birth) condition where there is narrowing of the aorta (the main blood vessel that carries oxygen-rich blood from the heart to the body). The narrowed segment (coarctation) is typically short, with the aorta opening up to normal size past the coarctation. However, the coarctation can cause problems with increased work of the heart and high blood pressure.

    • Coarctation of the aorta
      • Narrowing of the descending thoracic aorta distal to the left subclavian origin near the ductus arteriosus.
      • Occurs in 5-8% of all CHD but is likely underdiagnosed.
      • Clinical
        • Patient’s are often asymptomatic. Palpitation of the femoral artery and right upper brachial artery may show differences in delay of the beat and pressure indicating potential CoA. Hypertension on routine blood pressure check or for headache evaluation may indicate presence.
        • Neonates may have congestive heart failure and/or shock when the ductus arteriosus closes.
        • Murmur – May be normal or have continuous murmur in interscapular area which reveals significant collateral blood flow.
        • Evaluation
          • Electrocardiogram may be normal or have left ventricular hypertrophy.
          • Chest radiograph may show rib notching in older children and adults.
        • Treatment – balloon angioplasty, stenting in older children and adults, potentially surgery. The earlier patients receive treatment the more likely that patients become normotensive.

    CoA is not the same as an interrupted aortic arch (IAA) which is caused by a discontinuous aorta obstructing blood flow to the descending aorta. Blood flow is dependent on a PDA. There are 3 different types of IAA and it is commonly associated with LVOT and VSDs. Because of the severe obstruction and other accompanying CHD, patients usually present early and with more severe problems.

    Questions for Further Discussion
    1. What are indications for interventional versus open-heart cardiac procedures for CHD?
    2. What are the causes of hypertension? A review can be found here
    3. What are complications of hypertension?

    Related Cases

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

    To view current news articles on this topic check Google News.

    To view images related to this topic check Google Images.

    To view videos related to this topic check YouTube Videos.

    Sarrechia I, Miatton M, Francois K, et al. Neurodevelopmental outcome after surgery for acyanotic congenital heart disease. Res Dev Disabil. 2015;45-46:58-68. doi:10.1016/j.ridd.2015.07.004

    Rohit M, Shrivastava S. Acyanotic and Cyanotic Congenital Heart Diseases. Indian J Pediatr. 2018;85(6):454-460. doi:10.1007/s12098-017-2454-6

    Riggs KW, Tweddell JS. How Small Is Too Small? Decision-Making and Management of the Small Aortic Root in the Setting of Interrupted Aortic Arch. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2019;22:21-26. doi:10.1053/j.pcsu.2019.02.004

    Author
    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa