Congenital Heart Diseases Flashcards
Epidemiology of congenital heart diseases?
Prevalence is 8-10 per 1000 live births in the world (the same in Europe), specifically in Italy 5-10 per 1000 children, 4000-4500 patients every year, 30% of which will become symptomatic in the first months of life. The most frequent CHD are septal defects.
Frequency : ventricular septal defect 30-35%, atrial septal defect 6-8%, patent ductus arteriosus 6-8%, coarctation of aorta 5-7%…
How does fetal circulation work? What are some congenital heart defects?
Placenta is the main place where, takes place, so it acts as lungs for the fetus. In the placenta there are 2 arteries and 1 vein, the umbilical vein. The foremen ovale is a hole than allows the blood to bypass the lungs since they are not being used, when the umbilical cord is cut the increase in systemic pressure should close the hole.
In PFO, patent foramen ovale, the hole does not close.
In PDA, patent ductus arteriosus, the blood vessel in the developing fetus connecting the trunk of the pulmonary artery to the proximal descending aorta is supposed to close in the first week of life but doesn’t. Can be then closed surgically.
What is a shunt?
The shunt occurs when some blood passes from the left to the right or from the right to the left circulation, not just from artery to veins and vice versa but also the cardiac structures. Physiologically the rabo between Qp (pulmonary blood) and Qs (systemic blood) is 1: Qp/Qs = 1 since the same amount of blood goes into the right circulation and into the left circulation.
R-L shunt : Qp/Qs <1, more blood goes into the left circulation. This may cause cyanosis as there is a reduction in O sat in the blood.
L-R shunt : Qp/Qs >1, more blood goes into the right circulation.
What is an atrial septal defect? Morphology? Pathophysiology?
6-8% of congenital heart disease, preference for females (2:1). It is often sporadic, associated to genetic syndromes such as down, noonan and Williams.
Morphology : it is an abnormal communication between the two atria and can be found in various positions within the atrial septum.
- Ostium II defect (50-70%) : is the most common type
of interatrial defect and occurs in the center of the atrial septum within the oval fossa. - Ostium I defect (30%) : occurs in the lower part of the
atrial septum near its junction with the interventricular septum and is classified as an atrial ventricular septal defect as well. - Sinus venousus defect (10%): can be located in 2
places. Superior sinus venousus defect when located at
the orifice of the SVC and inferior sinus venousus defect when located at the orifice of the inferior venacava, less common
than the superior one.
• coronary sinus defect (rare) : is located in the mouth of
the coronary sinus, thus creating a communicabon between the coronary sinus and the left atrium.
Pathophysiology : Usually causes a L-R shunt. The direction and magnitude of the shunt are determined by the size of the defect, atrial pressure, compliance of the ventricles, vascular resistance.
Clinical aspects of atrial septal defect? How is it diagnosed?
The clinical aspects depend on the size of the defect. Usually children have no symptoms and therefore it is found incidentally. Larger defect may cause symptoms.
Defects smaller than 5 mm may close spontaneously within 4th year of life. Larger defect never close. They main causes of morbidity and mortality are : CHF usually in third to fourth decade, pulmonary hypertension, atrial arrhythmias and paradoxical embolism due to a clot in inferior limbs passes through defect into systemic circulation.
Diagnoses : Auscultation may reveal a systolic murmur at the pulmonary area due to the increased volume through pulmonary valve, and splitting of the second heart sound due to the increased stroke volume of right ventricle.
ECG usually shows RBBB and sings of RA enlargement, chest x ray can show cardiomegaly and echocardiography is the gold standard and allows comprehensive evaluations.
How is atrial septal defect treated?
Closure of ASD is indicated when the defect is hemodynamically relevant: Qp/Qs>1,5; right cavity enlargement. Only real contraindication is irreversible pulmonary hypertension ASD closure can cause right ventricle failure.
Procedures :
- Corrective surgery : the surgical approach may be performed either
through median sternotomy or right thoracotomy. The defect is repaired by suture or with placement of a pericardial or other patch through the right atrium. For surgery the best approach is with a right mid axillary incision.
- Percutaneous intervention : catheter inserted in right femoral artery and advanced to the RA. Catheter is pushed through defect into LA, distal disk is opened and device is retracted to deploy disc in defect. Finally the proximal disk is opened into the RA and the guiding catheter is retracted in order to deploy the disk.
What is a ventricular septal defect? Morphology? Pathophysiology?
VSD is the most common type of congenital heart disease and occurs in 32% of infants born with CHD.
Morphology : It involves an abnormal communication between the right and left ventricle that can be found in various positions within the ventricular septum. Most common ones :
- Supracrystal or double committed defect—> is located above
the crystasupraventricularis and is superiorly delineated by the fibrous continuity between the aorta and the pulmonary artery.
- Muscular defect—> can be located anywhere within the
ventricular septum, has a completely muscular border, central muscular or apical muscular defect.
- Paramembraneous defect—> is the most common one and
involves the membrane’s interventricular septum below the aorta.
Pathophysiology : Blood pressure is usually higher in the left ventricle than in the right ventricle therefore blood flows across the defect from left towards right causing a left to right shunt, the magnitude of which depends on the size of the defect. The left to right shunt usually causes an increase in right ventricular pressure and progression to the pulmonary artery vascular disease.
What are some clinical aspects of ventricular septal defect? Diagnoses?
Clinical aspects of VSD depend on the size of the defect and pulmonary vascular resistance :
- Small defects—> may cause no symptoms and are most likely to close spontaneously.
- Medium defects—> may cause no symptoms or may cause recurrent respiratory infections and retarded growth.
- Large defects may cause recurrent respiratory infections and retarded growth they may even cause severe heart failure during the first months of life.
Diagnoses : In children with ventricular septal defect a systolic murmur may be heard but in case of high right ventricular pressure no systolic murmur may be heard.
ECG may reveal no evidence of defects but might show biventricular hypertrophy in case of large defects. Chest x ray may show cardiomegaly. Echocardiography shoes comprehensive diagnoses and is gold standard.
How is ventricular septal defect treated?
- Palliative surgery : involves pulmonary artery banding in which we narrow the pulmonary artery in order to reduce pulmonary artery flow and pressure allowing patients to reach the ideal age for corrective surgery. Palliative surgery should be performed for the following cases of VSD—> infants with multiple defects should undergo surgical palliation during the first months of life, underweight children who should not undergo corrective surgery and the extra corporeal circulation, infants with other associated congenital heart diseases for example coarctation of the aorta, infants with severe respiratory infections.
- Corrective surgery : is carried out under extra corporeal circulation and involves closure of the ventricular septal defect with placement of a pericardial patch or a dacron patch. According to the type of the defect there are 3 different surgical approaches :
- transatrial approach through the right atrium—> firstly a right atriotomy is performed and surgeons proceed with the
evaluation of the defect through the tricuspid valve, then the defect is repaired with placement by suture of a pericardial or other patch, finally closure of the right atrium is carried out. - transventricular approach through the right ventricle. For example it is used for the apical muscular defect, specifically through the right ventricular apex.
- pulmonary artery approach, the supracrystal defects may be approached through the pulmonary artery.
Percutaneous intervention:
How is ventricular septal defect treated?
- Palliative surgery : involves pulmonary artery banding in which we narrow the pulmonary artery in order to reduce pulmonary artery flow and pressure allowing patients to reach the ideal age for corrective surgery. Palliative surgery should be performed for the following cases of VSD—> infants with multiple defects should undergo surgical palliation during the first months of life, underweight children who should not undergo corrective surgery and the extra corporeal circulation, infants with other associated congenital heart diseases for example coarctation of the aorta, infants with severe respiratory infections.
- Corrective surgery : is carried out under extra corporeal circulation and involves closure of the ventricular septal defect with placement of a pericardial patch or a dacron patch. According to the type of the defect there are 3 different surgical approaches :
- transatrial approach through the right atrium—> firstly a right atriotomy is performed and surgeons proceed with the
evaluation of the defect through the tricuspid valve, then the defect is repaired with placement by suture of a pericardial or other patch, finally closure of the right atrium is carried out. - transventricular approach through the right ventricle. For example it is used for the apical muscular defect, specifically through the right ventricular apex.
- pulmonary artery approach, the supracrystal defects may be approached through the pulmonary artery.
Percutaneous intervention : ??
What is coarctation of the aorta? Clinical aspects?
Epidemiology : COA represents 5% of CHD, affects 4 per 10 000 live births. If isolated is more present in males, if present with other CHD the prevalence is the same between males and females.
It can present in 3 different ways :
- Isolated (30%) : no other disease is present.
- Syndromic pattern : with syndromes such as Turner syndrome, Noonan syndrome or the Schone complex.
- Associated (70%) : with lesions decreasing aortic flow like VSD (40%), bicuspid aortic valve (50%), aortic stenosis, mitral valve pathology.
It is usually situated at the isthmus part of the descending aorta.
The clinical aspect of this defect changes depending on the age at which the diagnosis is being made :
- Neonatal: severe obstrucbon with fast duct closure
- Infantile : moderate obstruction with slow (weeks-months) duct closure, clinical presentation includes difficult feeding, failure to thrive, sweating, LV hypertrophy, systolic murmur.
- Adult : mild obstruction evolving with time and developing collateral circulation, clinical presentation includes hypertension with associated symptoms, poor exercise tolerance, systolic murmur.
How is coarctation of the aorta diagnosed and treated?
Diagnoses :
- Chest X-Ray—> shows 2 pathognomonic signs in older children ; rib notching and the sing sign.
- ECG—> shows early signs of left ventricle dominance.
- Echocardiography—> gives anatomic information such as trans-coarctation gradient and gives an evaluation of abdominal aorbc pulsablity and diastolic flow.
MRI/CT—> show excellent structural detail of the aortic arch and its branches and detects important collateral arteries.
Treatment :
- Surgical—> Usually we prefer a surgical approach in newborns or infants up to 25 kg. One possibility is end-to-end anastomosis, in which we need the tissue to be elastic, like in the newborn. If there is a long coarctation segment, you may use some tissue-like patch that you can suture enlarging the diameter of the descending aorta.
- Percutaneous—> after 25 kilos, you may treat the patient with a transcatheter approach. A catheter is inserted over a guide wire passing through the coarctation segment after which you may insert a stent. Usually a covered stent is preferred because it reduces the risk of dissection.
Re-coarctation in a newborn occurs in 12% of cases. At this point, you don’t go through a surgical approach again, but you may do a balloon angioplasty, because you need to enlarge the fibrotic tissue of the scarring.
What is tetralogy of fallot? Pathophysiology? Clinical aspects?
Tetralogy of Fallot is the most common type of cyanotic heart disease, which is classically understood to involve 4 anatomical defects:
1. A stenosis of the right ventricular outflow tract.
2. A wide, subaortic ventricular septal defect.
3. A shift of the aorta towards the right side, overriding the aorta.
4. A right ventricular hypertrophy, a consequence of the
infundibular stenosis.
Pathophysiology : Through the ventricular septal defect, blood flows from right towards left because of an increase in blood pressure in the right ventricle due to the ouylow tract stenosis. Consequently, oxygen or blood mixes with oxygen-rich blood, and that causes the cyanosis.
Clinical aspects of the Tetralogy of Fallot depend on the degree of the right ventricular outflow tract stenosis.
Primary symptoms are:
- Cyanosis—> characterizes the Tetralogy of Fallot. Children with mild infundibular stenosis may not present cyanosis. These cases are referred to as pink tetralogy of fallot.
- Anoxic spells—> occur with severe infundibular stenosis, and cause a sudden and marked increase in cyanosis, followed by pallor and possible lipothymia.
- Fatigue—> occurs with severe infundibular stenosis. Children get tired easily, and they often squat down. They adopt a knee-chest posture.
- Retarded growth—> may occur.
- Systolic murmur—> three or four-six in the mesocardium, with single-second heart sound.
How is tetralogy of fallot diagnosed and treated?
Diagnoses :
- ECG—> shows right axis deviation and RV hypertrophy.
- Chest x ray—> shows pulmonary hypoperfusion and left cardiac border uplifted apex (boot shaped heart).
- Echocardiography—> gold standard
- MRI—> can be used after echo if more information is needed.
Treatment :
- Palliative surgery—> Palliative surgery consists in the construction of a shunt so a connection between the aorta (or its branches) and the pulmonary artery to increase blood flow into the lungs.
- Corrective surgery—> is the sole definibve treatment for this disease. It is carried out under extracorporeal circulation, and it follows 3 main steps. Resection of the infundibular hypertrophy, closure of the ventricular septal defect and reconstruction of the pulmonary artery.
What are the different corrective surgical approaches used to treat tetralogy of fallot?
Transventricular approach :
1. Involves a longitudinal incision of the right infundibulum.
2. Followed by the resection of the hypertrophic septal band, the parietal band, and the supraventricular crest.
3. Once the right ventricular outflow tract stenosis has been relieved, ventricular septal defect is repaired with a pericardial or other patch. 4. In the end, the right ventricular outflow tract is reconstructed using a pericardial or other patch. It’s not possible to suture because the muscle would scar, causing complications.
Transatrial approach :
Surgeons perform the transatrial approach in order to close the
ventricular septal defect. They open the right atrium and, through the tricuspid valve they repair the defect with placement by suture of
a pericardial or other patch. When possible the transatrial approach is better because the patch in the right ventricle is the main cause for arrhythmias during the lifespan.
Transannular approach :
1. The hyperplasia of the pulmonary artery ring and trunk the pulmonary artery needs to be enlarged through a transannular incision even removing the valve.
2. This procedure involves the resection of the hypertrophic septal band, the parietal band and of the supraventricular crest.
3. Once the right ventricular outflow tract stenosis has been relieved ventricular septal defect is repaired with a pericardial or other patch.
4. A dysplastic pulmonary valve should be removed.
5. The right ventricular ouylow tract and the pulmonary artery are reconstructed using a pericardial or other patch.
Percutaneous approach : stent in the right ventricular outflow tract when possible. In case of pulmonary regurgitation a valve can be placed.
In severe cases a valve conduit is placed between the RV and the pulmonary artery bifurcation. The blood flows directly from the RV to the pulmonary artery.
