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

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

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 Transcatheter interventions for native aortic coarctation have been used for over 20 years. Transcatheter treatment for native aortic coarctation has been shown to be feasible, relatively safe and effective at short term and intermediate follow-up and is rapidly becoming the treatment of choice. Older age, however, seems to be a risk factor for suboptimal outcome after balloon angioplasty possibly due to a more fibrotic and rigid aorta. Especially in the full grown patient, stent placement seems a particularly attractive option, resulting in an almost complete relief of the gradient in 95% of the patients. Another benefit of stent placement is the ability to address longer segment coarctations, which typically have a poorer outcome after balloon angioplasty alone. Long-term results, however, are to be awaited. Concern after surgery or catheter intervention falls chiefly in seven categories: recoarctation, aortic aneurysm formation or aortic dissection, coexisting bicuspid aortic valve, endocarditis, premature coronary atherosclerosis, cerebrovascular accidents and systemic hypertension.
+== Transposition of the great arteries ==
+=== Case report ===
+=== Introduction ===
+Transposition of the great arteries (TGA) accounts for 5-8% of all congenital heart defects and occurs 2-3 times more frequently in males. TGA is best defined as a normal atrioventricular connection with an abnormal ventricular–arterial connection; the morphological left atrium is connected through the left ventricle with the pulmonary artery and the morphological right atrium through the right ventricle with the aorta. (figure 12)The aorta is often located on the right side and in front of the pulmonary artery (D-TGA). In 70 percent there is an isolated form of TGA, in 30 percent the TGA is accompanied by other heart defects, like VSD or obstruction of the left ventricle outflow tract.
+=== Pathophysiology ===
+The circulation in TGA patients is not serial but parallel (figure 13); the venous blood is returned to the systemic circulation through the right atrium and ventricle, while the arterial oxygenated blood is directed back into the pulmonary artery through the left atrium and ventricle. Due to this abnormal circulation there is severe cyanosis directly after birth, therefore it is critical for the ductus arteriosus and foramen ovale to remain open. Without treatment there is a mortality of 30% within one week, 50% within one month and 90% within one year. When an associated VSD is present the chances of survival are higher due to more shunting thus more oxygenated blood in the systemic circulation. These patients are able to reach early adulthood without corrective surgery or intervention. However the pulmonary hypertension that develops in this situation will eventually lead to severe problems.
+=== Treatment ===
+Mortality of TGA has dramatically improved from 90 percent for unoperated patients to rates of less than 5 percent following corrective surgery using the arterial switch operation. Most patients are referred for surgical repair during the first three to five days of life. The choice of surgical procedure is dependent on the presence and nature of other cardiac anomalies. In patients without any other cardiac defect (simple D-TGA), arterial switch operation is the recommended procedure. In general, the arterial switch operation has replaced the earlier atrial switch procedures developed by Mustard and Senning. In patients with D-TGA and a ventricular septal defect (VSD), the preferred procedure is arterial switch operation and VSD closure. In patients with D-TGA, large VSD, and significant pulmonary stenosis, the Rastelli procedure, an alternative surgical approach, should be considered. In some cases, arterial switch operation with or without repair of the left ventricular outflow obstruction is used. Both the arterial switch operation and Rastelli procedures are surgical anatomic corrections resulting in a morphologic left ventricle as the systemic ventricle. In comparison to atrial switch procedures, which involved the rerouting of venous return in the atria and are now only rarely performed, the arterial switch operation appears to have similar long-term survival rates with reduced long-term morbidity primarily due to a lower risk of atrial arrhythmias and heart failure. As a result, it is the recommended procedure in most patients with D-TGA.
+=== Outcome ===
+The long-term survival rates for patients with D-TGA following surgical correction are excellent for both arterial switch operation and atrial switch procedures. The long-term survival 20 years after discharge is about 95 and 80 percent for arterial switch and atrial switch respectively.  Progressive congestive heart failure and sudden death are the principal causes of death. Perioperative mortality is greater in patients with complex (additional cardiac anomaly) D-TGA compared to those with simple D-TGA. There are no clinical trials comparing outcomes of arterial switch and atrial switch procedures. Reintervention is common following both approaches.
+Patients who undergo surgical repair for D-TGA have a reduced exercise capacity primarily due to pulmonary disease. Patients after arterial switch operation appear to have better exercise capacity than those who underwent atrial switch procedures. The decrease in exercise capacity, however, does not limit ordinary activity as most patients meet the criteria for New York Heart Association functional class I.
+It appears that patients with D-TGA may have mild long-term neurodevelopmental impairment, most likely due to perioperative factors including hypoxemia, acidosis, cardiopulmonary bypass, and hemodynamic instability.
+== Congenitally corrected transposition of the great arteries ==
+=== Congenitally corrected transposition of the great arteries ===
+=== Introduction ===
+The congenitally corrected transposition of the great arteries (ccTGA) is characterized by a normal anatomical position of both atria, with an abnormal connection between the atria and the ventricles. The right atrium is connected with the left ventricle and the left atrium is connected with the right ventricle. (figure 14) Furthermore the aorta arises from the right ventricle and the pulmonary artery from the left ventricle. There are, in conclusion, abnormal atrioventricular connections and abnormal ventricular-arterial connections present in ccTGA.
+CcTGA is a very rare defect, accounting for about 1% of all congenital heart disease.
+=== Pathophysiology ===
+The blood flow in ccTGA is ‘corrected’ because oxygenated blood flows through the systemic circulation and deoxygenated blood is transported to the lungs.
+In this particular heart defect the right ventricle functions  as a systemic ventricle. With the atrioventricular valves following the position of the ventricles, the tricuspid valve is now the systemice AV-valve.
+Additionally the coronary arteries are a mirror image of the normal anatomic situation. The coronary artery on the right side of the heart runs like a morphological left coronary artery; starting with a main stem which divides into a left anterior descending and circumflex branch. The coronary artery on the left is the morphological right coronary artery, which now runs around the tricuspid valve on the left.
+Even the conduction system is abnormal in this congenital heart defect. Normally the AV node is positioned at the base of the interatrial septum, from where the His bundle arises into the interventricular septum. Due to misalignment in ccTGA there is no bundle directly from the normal AV node into the interventricular septum. Usually there is an additional AV node located more anterior and laterally from where a long bundle arises which runs beneath the pulmonary valve leaflets into the interventricular septum. Due to the long route this bundle is rather vulnerable. Where in normal hearts the electrical activation of the ventricles in the septum runs from left to right, in ccTGA it is the exact opposite; the septum is activated from right to left, which is visible on the ECG as an abnormal initial activation.
+There is a VSD present in 60% of all ccTGA patients, who will often become symptomatic at younger age. Pulmonary valve stenosis is seen in 30 – 50% of patients, usually in those who already have a VSD as well. Abnormal anatomy of the tricuspid valve (M. Ebstein like) is seen in 25-30% of patients, sometimes accompanied by VSD or pulmonary valve stenosis. More than 80 percent of patients have an abnormal function of the tricuspid valve, which often becomes insufficient.
+=== Evaluation ===
+When only ccTGA is present, without other cardiac defects, the diagnosis is often not recognized until adulthood. However, when there is a VSD and/or pulmonary valve stenosis present, it presents short after birth with cyanosis and heart failure or even a total AV-block.
+Adult patients are usually recognized due to an abnormal ECG, abnormal chest radiograph, systolic murmur due to the regurgitation of the systemic AV-valve, occurrence of atrial tachycardia or an AV-block. Reduced exercise capacity might be present.
+The ECG is the most typical for ccTGA; left heart axis deviation, septum activation in mirror image (no Q-wave in I, aVL and V6, no R-top in V1) and a rather deep Q-wave in III and aVF.  Echocardiography is a good diagnostic tool to review the exact anatomy. The right ventricle positioned on the left side is identified by the typical morphology of the trabeculae. Furthermore the tricuspid valve has a lower insertion compared to the mitral valve.
+=== Treatment and outcome ===
+Patients with ccTGA require lifelong follow up due to the risk of arrhythmias and associated sudden death, increase of pulmonary valve stenosis, increase of tricuspid valve regurgitation, supraventricular tachycardia, heart failure or endocarditis. Due to the complex anatomy and the low incidence of this pathology, this is best acquired at a specialised centre of congenital heart disease.
+Arrhythmias need treatment, preferably not with negative inotropic agents, but digoxin and possibly amiodaron are preferred. When presenting with atrial arrhythmias conversion to sinus rhythm is highly important in these patients, who are in need of their ‘atrial kick’.
+Many patients with ccTGA require pacemaker placement, often already in childhood or early adulthood. Frequent followup in these patients is required due to the high complication rate; dislocation of the lead which is located in the smooth-walled left ventricle and risk of infection or endocarditis.
+Determining the right time to replace the tricuspid valve is difficult in these patients. Preferably this is done just before the right systemic ventricle starts dilating and fails, but it remains an estimation which should be made for each individual patient.
+To restore normal blood flow through the ventricles, with the left ventricle functioning as the systemic ventricle, there is an option to perform a double switch operation. During this procedure both atria and both great arteries are switched, meaning a combination of the arterial switch and the atrial switch procedure. From a physiologic point of view this operation is worth considering while the left ventricle will function as systemic ventricle, however it is associated with a high perioperative mortality due to the extent of surgery. Furthermore the left ventricle requires training prior to surgery, to be able to cope with the high arterial pressure after years of low pulmonary pressure. In conclusion the chance of success of this double switch operation is very low in patients above 16 years of age.