Grown-up Congenital Heart Disease (GUCH): Difference between revisions

Grown-up Congenital Heart Disease (GUCH) (view source)

Revision as of 23:26, 22 January 2012

7,619 bytes added , 22 January 2012

no edit summary

Nja

401

edits

@@ Line 339: / Line 339: @@
 There is a paucity of data on the quality of life for patients with HLHS. In one report of survivors and their families, parents reported poorer functional health status than patients assessed at 18 years of age.
 Risk factors that lower survival include noncardiac congenital anomalies and/or genetic disorder, particularly chromosomal defects, prematurity, low birth weight for gestational age, and living in a high poverty neighborhood.
+== Tetralogy of Fallot ==
+=== Case report ===
+=== Introduction ===
+In 1888 Etienne Louis Arthur Fallot described the ‘maladie bleue’ as a combination of:
+* Stenosis of the pulmonary artery (PS)
+* Ventricular septal defect (VSD)
+* Deviation of the origin of the aorta to the right
+* Hypertrophic right ventricle
+This constellation of findings has since become known as tetralogy of Fallot (TOF). (figure 17)
+The prevalence of TOF is about 3.9 per 10.000 live births. This defect accounts for about 7 to 10 percent of cases of congenital heart disease and is one of the most common congenital heart lesions requiring intervention in the first year of life.
+=== Anatomy ===
+In fact there is only one anatomic abnormality in TOF; a misalignment of the interventricular septum. As a consequence the muscular part of the interventricular septum is not able to fuse with the cranial part of the septum (leaving a ventricular septal defect) and overriding of the aorta, which causes stenosis of the right ventricular outflow tract. The hypertrophy of the right ventricle is a direct consequence of the elevated pressure in the right ventricle due to the large unrestrictive VSD.
+=== Pathophysiology ===
+The combination of infundibular PS and a VSD causes the blood flow in utero to flow directly into the aorta, leading to a high chance of underdevelopment of the pulmonary valve and arteries. Therefore pulmonary valve stenosis and hypoplasia of the pulmonary arteries are often found in TOF patients. Stenosis at the origin or more distally of the right or left pulmonary artery are frequently found, so is total absence of (usually the left) pulmonary artery. Furthermore about 33% percent of all TOF patients has a descending aorta on the right side.
+The physiologic consequences of TOF are largely dependent upon the degree of right ventricular outflow obstruction. Since the VSD is typically large and unrestrictive, the pressure in the right ventricle reflects that of the left ventricle. As a result, the direction of blood flow across the VSD will be determined by the path of least resistance for blood flow, not by the size of the VSD. If the resistance to blood flow across the obstructed right ventricular outflow tract is less than the resistance to flow out of the aorta into the systemic circulation, blood will naturally shunt from the left ventricle to the right ventricle and into the pulmonary bed. In this situation, there is predominately a left-to-right shunt and the patient will be acyanotic.
+As the degree of right ventricular outflow obstruction increases, the resistance to blood flow into the pulmonary bed also increases. If the right ventricular obstruction is significant enough to increase resistance, it will be easier for blood to cross the VSD from the right ventricle into the left ventricle and go out the aorta, which now becomes the path of least resistance. This right-to-left shunt across the VSD will result in a large volume of desaturated blood entering the systemic circulation and cyanosis and polycythemia will ensue.
+One of the physiologic characteristics of TOF is that the right ventricular outflow obstruction can fluctuate. An individual with minimal cyanosis can develop a dynamic increase in right ventricular outflow tract obstruction with a subsequent increase in right-to-left shunt and the development of cyanosis. In the most dramatic situation, there can be near occlusion of the right ventricular outflow tract (RVOT) with profound cyanosis. These episodes are often referred to as "hypercyanotic spells". The exact etiology of these episodes is unclear, although there have been a number of proposed mechanisms, including increased infundibular contractility, peripheral vasodilatation, hyperventilation, and stimulation of right ventricular mechanoreceptors.
+=== Treatment ===
+Patients with TOF can undergo either palliative (shunts) or corrective (intracardiac repair) surgery. Although most children with TOF undergo intracardiac repair as their initial intervention, the principle of shunts remains an important palliative procedure for infants who may not be acceptable candidates for intracardiac repair due to prematurity, hypoplastic pulmonary arteries, or coronary artery anatomy.
+Patients with TOF can undergo either palliative (shunts) or corrective (intracardiac repair) surgery. Although most children with TOF undergo intracardiac repair as their initial intervention, the principle of shunts remains an important palliative procedure for infants who may not be acceptable candidates for intracardiac repair due to prematurity, hypoplastic pulmonary arteries, or coronary artery anatomy.
+Patients with TOF can undergo either palliative (shunts) or corrective (intracardiac repair) surgery. Although most children with TOF undergo intracardiac repair as their initial intervention, the principle of shunts remains an important palliative procedure for infants who may not be acceptable candidates for intracardiac repair due to prematurity, hypoplastic pulmonary arteries, or coronary artery anatomy.
+Intracardiac repair of TOF was reported by Lillehi in 1954. It consists of patch closure of the ventricular septal defect and enlargement of the RVOT. The latter is accomplished by relieving pulmonary stenosis, resecting infundibular and subinfundibular muscle bundles and if necessary by a transannular patch, creating unobstructed flow from the RV into the pulmonary arteries.
+=== Outcome ===
+A few decades ago the perioperative mortality in TOF patients was rather high (until 25 percent) but gradually declined to the current risk of around 3%. The survival in TOF patients after surgery is, although slightly less than the average population, considerably good. The longest follow-up cohort shows a survival rate of 85% after 35 years. However the rate of morbidity is very high in TOF patients due to a wide range of residual defects, that can increase over time. Therefore all patients with TOF require a lifelong, regular cardiologic follow up.
+The main complications of TOF include pulmonary regurgitation, residual right ventricular outflow tract obstruction, pulmonary hypertension and residual shunt.
+Intracardiac repair with a transannular RVOT patch can result in chronic severe pulmonary regurgitation. This leads to RV enlargement and patients may develop decreased exercise tolerance, right heart failure, and arrhythmias. A surgical prosthetic pulmonary valve may be necessary to restore the valve competence and improve RV function and functional status in TOF patients. Residual RVOT obstruction can persist after the original intracardiac operation due to hypertrophied subvalvar muscle, annular hypoplasia, pulmonary valve stenosis, supravalvar pulmonary stenosis, or branch pulmonary artery stenosis. Mild obstruction is usually well tolerated, but significant obstruction may require reoperation or catheter-based intervention. Relief of pulmonary artery stenosis by balloon dilation or stenting may be necessary prior to pulmonary valve replacement.
+Pulmonary hypertension can be present in TOF patients due to: hypoplastic pulmonary arteries with associated high vascular resistance, excessive shunting across the surgically constructed shunts (mainly Potts or Waterston shunts) or presence of multiple pulmonary artery stenosis.
+A residual VSD shunt is present in about 20 percent of all operated TOF patients, requiring a reoperation in 5 – 10 percent of them. Residual shunt might be due to detachment of the patch or an additional septal defect which was not recognized during surgery.