congetinal heart disease.pdf

Congenital Cardiovascular Disease Dr Bernadette O’Hare Senior Lecturer MSB Room 302 [email protected] 1 Learning Outcomes. •Understand the difference between foetal circulation and that of an adult (recap) •Describe the common congenital cardiovascular abnormalities. •Describe how congenital...

Congenital Cardiovascular Disease Dr Bernadette O’Hare Senior Lecturer MSB Room 302 [email protected] 1 Learning Outcomes. •Understand the difference between foetal circulation and that of an adult (recap) •Describe the common congenital cardiovascular abnormalities. •Describe how congenital cardiovascular disease can present. •Demonstrate a basic understanding of the management of a congenital cardiovascular disease. 2 Foetal circulation Because the foetal lungs are full of fluid and not yet used for respiration, there are mechanisms in the foetal circulation. 1. to ensure well-oxygenated blood gets to the left side of the foetal heart and thus to the coronary and cerebral circulation. 2. to bypass the lungs - only about 10% of the right ventricular output passes through the pulmonary vascular bed. 3 Foetal circulation- Ductus Venosis The placenta carries blood to the foetus through the umbilical vein. 25% of the blood volume is diverted to the ductus venosis. The remainder is distributed to the liver via the portal vein and the hepatic portal system. The blood then passes from the liver into the inferior vena cava and then the right atrium of the heart. The ductus venosus shunt is critical in delivering well-oxygenated blood to the left side of the foetal heart and thus to the coronary and cerebral circulation. http://cardiovascularsystemud.weebly.com/fetal-circulation.html4 Mechanisms in foetal circulation to bypass the lungs. High pulmonary vascular resistance in the foetus prevents a major portion of the cardiac output from entering the lungs, and blood flow is diverted to other organs via the foramen ovale and the ductus arteriosus 5 1. To bypass the lungs – foramen ovale The foramen ovale is an opening between the right and left atria in the foetus. Most of the foetal blood flows through this foramen directly from the right atrium into the left atrium, bypassing pulmonary circulation. After that, the blood flows into the left ventricle to pump blood through the aorta to the entire body. (From the aorta, some blood moves through the internal iliac arteries to the umbilical arteries and re-enters the placenta.) Source: http://cardiovascularsystemud.weebly.com/fetal-circulation.html 6 2. To bypass the lungs - ductus arteriosus Some of the blood enters the right ventricle, which pumps the blood into the pulmonary artery. During foetal life, the ductus arteriosus is a normal structure that allows most of the blood leaving the right ventricle to bypass the pulmonary circulation and pass into the descending aorta. http://cardiovascularsystemud.weebly.com/fetal-circulation.html7 Neonatal circulation – the transition With the first breath, the lungs are inflated, and pulmonary vascular resistance drops. The reduced pulmonary vascular resistance results in increased flow through the pulmonary arteries, increasing the pressure in the left atria and an abrupt reduction in the pressure on the right side of the heart. These changes produce functional closure of the foramen ovale. The blood no longer bypasses the pulmonary circulation; as a result, the neonate’s blood becomes oxygenated, and the systemic and pulmonary circulations start. 8 Congenital heart defects (CHD) Congenital heart defects (CHD) are problems with the heart's structure that are present at birth. Congenital heart defects change the normal flow of blood through the heart. 9 Congenital heart defects (CHD) About 1 in 4 babies born with a heart defect have a critical congenital heart defect. Babies with critical CHD need surgery or other procedures in the first year of life. https://www.cdc.gov/ncbddd/heartdefects/index.html 10 Congenital heart defects (CHD). Congenital Heart Defects (CHD) are the most common type of congenital disability 0.8% of live births. Many of these defects are simple conditions that need no treatment or are relatively easily fixed. The diagnosis and treatment of complex heart defects have greatly improved over the past few decades. Many children with complex heart defects survive to adulthood and can live active, productive lives. 11 Congenital heart defects are the most common type of birth defect. Nevertheless, complex CHD causes more deaths in the first year of life than any other congenital disability. Some babies are born with complex congenital heart defects that require special medical/surgical care soon after birth (Critical Congenital Heart Disease). https://www.cdc.gov/ncbddd/heartdefects/index.html 12 Congenital heart defects (CHD) There are many types of congenital heart defects and can involve: 1. The interior walls of the heart 2. The valves inside the heart 3. The arteries and veins that carry blood to the heart or away from the heart to the body 13 Congenital heart disease is often divided into 2 types: non-cyanotic and cyanotic (blue skin colour caused by a lack of oxygen) . Acyanotic: Cyanotic: • • • • • • • Tetralogy of Fallot • Total anomalous pulmonary venous return • Transposition of the great vessels • Tricuspid atresia • Truncus arteriosus • Hypoplastic left heart • Pulmonary atresia Ventricular septal defect (VSD) Atrial septal defect (ASD) Pulmonary stenosis Aortic stenosis Coarctation of the aorta Patent ductus arteriosus (PDA) 5 Ts 14 Classification Left-to-right shunts Lesions that allow blood to shunt from the left to the right side of the heart. They are associated with varying degrees of increased pulmonary blood flow and are typically acyanotic. Examples include:  Ventricular septal defect (VSD)  Atrial septal defect (ASD)  Patent ductus arteriosus (PDA) 15 Classification Right-to-left shunts Lesions that result in deoxygenated blood reaching the aorta. Examples include:  Tetralogy of Fallot (TOF)  Transposition of the great arteries (TGA)  Pulmonary valve atresia with or without a VSD  Truncus arteriosus  Tricuspid Atresia  Total anomalous pulmonary venous return 16 Classification Obstructive valvular and non-valvular lesions Examples include:  Coarctation of the aorta  Pulmonary valve stenosis (PS)  Aortic valve stenosis (AS 17 18 19 Ventricular Septal Defects (VSDs) 20% of cases Subtypes based on the location of the defect. VSDs can be small, medium, or large. Small VSDs don't cause problems and may close on their own. Medium VSDs are less likely to close on their own and may require treatment. Large VSDs allow a lot of blood to flow from the left ventricle to the right ventricle. Extra blood flow increases blood pressure in the right side of the heart and the lungs. 20 Ventricular Septal Defects (VSDs) With larger defects, the baby may develop signs of excess pulmonary blood flow such as Tachypnoea Tachycardia Pallor Poor feeding and poor weight gain. 21 Ventricular Septal Defects (VSDs) The heart’s extra workload can cause heart failure and poor growth. If the hole isn't closed, high blood pressure can scar the arteries in the lungs leading to the dreaded complication of Pulmonary Hypertension and irreversible damage leading to shunt reversal and Eisenmenger’s Syndrome. This doesn’t usually develop until two years. 22 Ventricular septal defect (VSD) - clinical • Pan systolic murmur • Loud second heart sound • Heart failure In larger defects, there is cardiac enlargement and increased pulmonary vascular markings on CXR, and ECG reveals left ventricle hypertrophy, ECHO shows the defect. 23 Ventricular septal defect (VSD) Small VSDs and those unassociated with excessive pulmonary blood flow do not require closure. Large VSDs and defects associated with excess pulmonary blood flow may require diuretics and an increased caloric formula, followed by closure of the defect (either surgical closure or transcatheter device closure). Those with increased pulmonary blood flow and failure to thrive are closed surgically between 1 and 4 months of age; most large defects are typically closed by 6 to 9 months of age. Medium and large VSDs that need treatment can be repaired using a catheter procedure or open-heart surgery. 24 25 Patent Ductus Arteriosus (PDA) • PDA 9% to 12% of all CHD • Persistent patency occurs in 1 in 5000 live births in full-term infants but is much more common in pre-term neonates • In pre-term infants, a PDA has been noted during admission to hospital in 42% of neonates weighing 500 to 999 g, 21% weighing 1000 to 1499 g, and 7% weighing 1500 to 1750 g. • There is also a 30-fold higher incidence in patients born at higher altitudes. PDA http://emedicine.medscape.com/article/891096-overview 26 Patent Ductus Arteriosus (PDA) PDA 9% to 12% of all CHD PDA is a persistent communication between the descending thoracic aorta and the pulmonary artery that results from failure of normal physiological closure of the foetal ductus. Left to right shunt the blood flows from the aorta to the pulmonary aorta Continuous murmur as the pressure in the pulmonary artery is lower than in the aorta throughout the cardiac cycle. The murmur is continuous because the aortic pressure is higher than the pulmonary artery pressure during both systole and diastole. http://emedicine.medscape.com/article/891096-overview 27 Patent Ductus Arteriosus (PDA) ECG and CXR often are normal. In a large PDA, bi-ventricular hypertrophy on the surface ECG, and increased pulmonary blood flow and cardiomegaly on CXR may be present. Echocardiography allows the delineation of the PDA anatomy and the direction and volume of the shunt. http://emedicine.medscape.com/article/891096-overview 28 Patent Ductus Arteriosus (PDA) In a newborn, if there is significant respiratory distress or impaired systemic oxygen delivery is present, treat with intravenous indomethacin or ibuprofen. For older children, closure is recommended to avoid the risk of infective endocarditis - options are catheter closure and surgical ligation. http://emedicine.medscape.com/article/891096-overview 29 30 Atrial septal defect (ASD) 6-10% (4 subtypes based on the location of the defect). ASDs can be small, medium, or large. Small ASDs allow only a little blood to leak from one atrium to the other. They don't affect how the heart works and don't need any special treatment. Many small ASDs close on their own as the heart grows during childhood. Medium and large ASDs allow more blood to leak from one atrium to the other. They’re less likely to close on their own. https://www.nhlbi.nih.gov/health/health-topics/topics/chd/types 31 Atrial septal defect (ASD) Children with isolated ASDs are frequently asymptomatic. It is the most missed CHD diagnosis in childhood, frequently not discovered until adulthood. An untreated defect leads to exercise intolerance and atrial arrhythmias in the third or fourth decade of life. https://www.nhlbi.nih.gov/health/health-topics/topics/chd/types 32 Atrial septal defect (ASD) No symptoms/recurrent chest infections In moderate to large lesions Signs – ejection systolic murmur, pulmonary area. The murmur is caused by increased blood flow through the pulmonary valve, not through the ASD. A split second heart sound may be heard. https://www.nhlbi.nih.gov/health/health-topics/topics/chd/types 33 Atrial septal defect (ASD) CXR usually normal in a small ASD ECG may be normal in a small lesion but in a larger lesion there may be right atrial enlargement, right ventricular enlargement or right axis deviation. Medium and large ASDs that need treatment involve either an operation or percutaneous device closure. https://www.nhlbi.nih.gov/health/health-topics/topics/chd/types 34 Atrial septal defect (ASD) 10%. Apical 4-chamber echocardiographic image of an ostium primum ASD (arrows). LA: left atrium; LV: left ventricle; RA: right atrium https://bestpractice.bmj.com/topics/en-gb/1099 Subtypes of ASD. A: sinus venosus; B: ostium secundum; C: ostium primum; D: unroofed coronary sinus 35 36 Tetralogy of Fallot (TOF) A combination of four defects. 4-8% Pulmonary valve stenosis or right ventricular outlet obstruction (RVOT) A large VSD An overriding aorta. The aorta is located between the left and right ventricles, directly over the VSD. As a result, oxygen-poor blood from the right ventricle can flow directly into the aorta instead of the pulmonary artery Right ventricular hypertrophy because of the RVOT https://www.nhlbi.nih.gov/health/health-topics/topics/chd/types 37 Tetralogy of Fallot (TOF) A combination of four defects. Most patients with TOF, have progressive cyanosis after birth followed by dyspnoea on exertion as a young child. Faltering growth may be present. Hypoxic episodes or 'tet spells’ consist of an abrupt onset of rapid shallow breathing, increased agitation, cyanosis, and a decrease in murmur intensity due to reduced blood flow through the RVOT. Older children with hypoxic spells will squat to increase systemic vascular resistance and thereby reduce hypoxaemia https://www.nhlbi.nih.gov/health/health-topics/topics/chd/types 38 Tetralogy of Fallot (TOF) Most are diagnosed: • antenatally or • following the identification of a murmur in the first two months of life. • Cyanosis at this stage may not be apparent, although a few present with severe cyanosis in the first few days of life. • A loud ejection systolic murmur is heard at the left upper sternal border with radiation to both axillae due to the RVOT obstruction. https://www.nhlbi.nih.gov/health/health-topics/topics/chd/types 39 40 Palliative surgery for TOF Infants who are very cyanosed in the early neonatal period require a shunt to increase pulmonary blood flow. This is usually done by the surgical placement of an artificial tube between the subclavian artery and the pulmonary artery (a modified Blalock–Taussig shunt). This redirects a large portion of the partially oxygenated blood leaving the heart for the body into the lungs, increasing flow through the pulmonary circuit and greatly relieving symptoms in patients. 41 Surgery for TOF Surgery involves closing the VSD and relieving right ventricular outflow tract obstruction, sometimes with an artificial patch which extends across the pulmonary valve. The timing of the surgery will depend on how narrow the pulmonary artery is. https://www.kidsheartshouston.com/images/answers/Tetralogy-of-Fallot--42 Surgical-Repair-web.jpg 43 Transposition of The Great Arteries. The pulmonary arteries are supplied by the left ventricle and the aorta by the right ventricle. This, of course, is the opposite of the normal arrangement. Infants can only survive if there is a shunt between the two sides of the heart. Fortunately, some naturally occurring associated anomalies, e.g. VSD, ASD and PDA, can achieve this mixing. Normal Transposition 44 http://www.heartpoint.com/congtranspos.html Transposition of The Great Arteries. Cyanosis is always present. The second heart sound is often loud and single. Usually, no murmur. Normal Transposition 45 http://www.heartpoint.com/congtranspos.html Transposition of The Great Arteries. In the sick cyanosed neonate, the key is to improve mixing. Maintaining the patency of the ductus arteriosus with a prostaglandin infusion is mandatory. A balloon atrial septostomy may be a life-saving procedure and needs to be performed in 20% of patients. A catheter with an inflatable balloon at its tip is passed through the umbilical or femoral vein and then through the right atrium and foramen ovale. The balloon is inflated within the left atrium and then pulled back through the atrial septum. This tears the atrial septum, renders the flap valve of the foramen ovale incompetent, and allows the mixing of the systemic and pulmonary venous blood within the atrium. 46 Transposition of The Great Arteries. Patients with transposition of the great arteries will require an operation, usually the arterial switch procedure in the neonatal period. This operation is performed in the first few days of life. The pulmonary artery and aorta are transected above the arterial valves and switched over. 47 48 Atrioventricular Septal Defect (AVSD) An AVSD is a heart defect in which there are holes between the chambers of the right and left sides of the heart, and the valves that control blood flow between these chambers may not be formed correctly. This condition is also called an atrioventricular canal (AV canal) or endocardial cushion defect. AVSD is common in babies with Down syndrome, a genetic condition that involves an extra chromosome 21 (also called trisomy 21). https://www.cdc.gov/ncbddd/heartdefects/avsd.html 49 Atrioventricular Septal Defect (AVSD) Presentation Antenatal ultrasound screening or routine echocardiography screening in a newborn infant with Down syndrome Presentation Cyanosis at birth or heart failure at two weeks to 3 weeks of life No murmur heard Management Treat heart failure medically (as for large VSD) and surgical repair at three months to 6 months of age. 50 CHD affecting the valves inside the heart. Atresia. This defect occurs if a valve doesn't form correctly and lacks a hole for blood to pass through. Atresia of a valve generally results in more complex congenital heart disease. Stenosis. This defect occurs if the flaps of a valve thicken, stiffen, or fuse. As a result, the valve cannot fully open. Thus, the heart must work harder to pump blood through the valve. Regurgitation. This defect occurs if a valve doesn't close tightly. As a result, blood leaks back through the valve. 51 CHD causing outflow obstruction (Mild, may present in adolescence) 52 53 Pulmonary valve stenosis. The most common valve defect is pulmonary valve stenosis, which is a narrowing of the pulmonary valve. This valve allows blood to flow from the right ventricle into the pulmonary artery. The blood then travels to the lungs to pick up oxygen. Pulmonary valve stenosis can range from mild to severe. Most children with this defect have no signs or symptoms other than a heart murmur. Treatment isn't needed if the stenosis is mild. 54 http://www.chfed.org.uk/how-we-help/information-service/heart-conditions/pulmonary-stenosis/ Pulmonary valve stenosis. Animation of normal heart Animation of pulmonary stenosis http://www.chfed.org.uk/how-we-help/information-service/heart-conditions/pulmonary-stenosis/ 55 Pulmonary valve stenosis. Most are asymptomatic An ejection systolic murmur is best heard at the upper left sternal edge; A small number of neonates with critical pulmonary stenosis have duct-dependent pulmonary circulation and present in the first few days of life with cyanosis. In babies with severe pulmonary valve stenosis, the right ventricle can get overworked trying to pump blood to the pulmonary artery. These infants may have signs and symptoms of heart failure. 56 http://www.chfed.org.uk/how-we-help/information-service/heart-conditions/pulmonary-stenosis/ Pulmonary valve stenosis. A normal to a widely split second heart sound and an ejection systolic murmur at the pulmonary valve area. In babies with severe pulmonary valve stenosis, the right ventricle can get overworked trying to pump blood to the pulmonary artery. These infants may have an increased right ventricular impulse and signs and symptoms of heart failure. ECG may reveal right axis deviation and CXR may show signs of right ventricular enlargement. 57 http://www.chfed.org.uk/how-we-help/information-service/heart-conditions/pulmonary-stenosis/ Balloon Valvuloplasty for Severe Pulmonary Valve Stenosis. Pulmonary valve stenosis is treated with a catheter procedure - balloon dilatation is the treatment of choice in most children. 85% do not require further intervention. https://www.youtube.com/watch?v=JNoExxUgT9A http://www.hopkinsmedicine.org/healthlibrary/test_procedures/cardiovascular/valvuloplasty_92,P07990/ 58 59 Aortic valve stenosis. Aortic valve stenosis 5% One of 4 subtypes of left ventricular outlet obstruction (LVOT). Results from minor to severe degrees of aortic valve maldevelopment or thickening. http://emedicine.medscape.com/article/894095-overview 60 Aortic valve stenosis. Presentation depends on the severity of the obstruction. Most patients are asymptomatic. Older patients may present with chest pain or syncope. In the neonatal period, those with critical aortic stenosis and ductdependent systemic circulation may present with severe heart failure leading to shock. http://www.heart-valve-surgery.com/bicuspid-aortic-valve-symptoms.php 61 Aortic valve stenosis. A subset of patients present with poor left ventricular function, low cardiac output, and signs of shock and congestive heart failure ('critical' aortic stenosis). An estimated 10-15% of patients with aortic valve stenosis present with the condition when they are younger than one year due to severe stenosis. http://www.heart-valve-surgery.com/bicuspid-aortic-valve-symptoms.php 62 Aortic valve stenosis. Most present with an asymptomatic murmur. Those with severe stenosis may present with reduced exercise tolerance, chest pain on exertion, or syncope. Signs Small-volume, slow-rising pulses Carotid thrill (always) Ejection systolic murmur maximal at the upper right sternal edge radiating to the neck Delayed and soft aortic second sound Apical ejection click. http://www.heart-valve-surgery.com/bicuspid-aortic-valve-symptoms.php 63 Aortic valve stenosis. ECG inconsistently shows evidence of left ventricular hypertrophy. CXR may reveal a prominent aorta because of post-stenotic dilation. Echocardiography helps accurately evaluate aortic valve morphology and estimate the pressure gradient across the LVOT. http://www.heart-valve-surgery.com/bicuspid-aortic-valve-symptoms.php 64 Aortic valve stenosis. Infants with severe valvular stenosis require balloon valvuloplasty, although surgery may be required for co-existent aortic regurgitation. Surgical valvotomy or valve replacement is considered for older children and adults. Balloon dilatation in older children is generally safe and uncomplicated, but this is much more difficult and dangerous in neonates. 65 http://www.msdmanuals.com/en-gb/home/heart-and-blood-vessel-disorders/heart-valve-disorders/aortic-stenosis 66 Left heart outflow obstruction in the sick infant In the first week of life, heart failure usually results from left heart obstruction. If the obstructive lesion is very severe, arterial perfusion may be predominantly by right-to-left blood flow via the arterial duct, so-called duct-dependent systemic circulation. Closure of the duct under these circumstances rapidly leads to severe acidosis, collapse and death unless ductal patency is restored 67 Duct dependent coarctation of the aorta This is due to arterial duct tissue encircling the aorta at the duct’s insertion point. It is commonly associated with a bicuspid aortic valve (in 70% of patients). When the duct closes, the aorta also constricts, causing severe obstruction to the left ventricular outflow. This is the most common cause of collapse due to left outflow obstruction. 68 Duct dependent coarctation of the aorta Examination on the first day of life is usually normal. Neonates usually present with acute circulatory collapse at about two days of age when the duct closes. • A sick baby with severe heart failure • • Absent femoral pulses • • Severe metabolic acidosis. Coarctation is amenable to surgical repair or balloon dilation. 69 Prenatal Diagnosis of Congenital Heart Defects. In high-income countries, between 18 - 20 weeks’ gestation can lead to 70% of those infants who require surgery in the first six months of life being diagnosed antenatally. 70 Symptoms Symptoms depend on the condition. Although congenital heart disease is present at birth, the symptoms may not appear immediately. Some problems, such as a small VSD, ASD, or PDA, may never cause any problems. 71 Murmurs The most common presentation of minor congenital heart disease is a heart murmur. Even so, most children with murmurs have a normal heart. They have an ‘innocent murmur’, which can be heard at some time in almost 30% of children. It is essential to distinguish an innocent murmur from a pathological one. 72 Heart Failure Symptoms • Breathlessness (particularly on feeding or exertion) • Sweating • Poor feeding • Recurrent chest infections. Signs • Poor weight gain or faltering growth • Tachypnoea • Tachycardia • Heart murmur, gallop rhythm • Enlarged heart • Hepatomegaly • Cool peripheries. 73 CHDs Causes and associations 74 Extracardiac anomalies in CHD. Extracardiac anomalies (ECA) occur in 25% of infants seen during the first year of life for significant cardiac disease. Often the ECA are multiple and one-third of the affected infants have some established syndrome. The most frequent ECA are in the musculoskeletal system or associated with a specific syndrome. The presence of an ECA significantly increases the mortality in infants with CHD. https://www.ncbi.nlm.nih.gov/pubmed/124046 http://pmj.bmj.com/content/78/922/469 75 76 Summary. •Understand the difference between foetal circulation and that of an adult. •Describe the common congenital cardiovascular abnormalities. •Describe how congenital cardiovascular disease can present. •Demonstrate a basic understanding of the management of a congenital cardiovascular disease. 77