Adult congenital heart disease

Adult congenital heart disease (ACHD) is a rising burden on healthcare systems. While neonatal mortality from congenital heart disease has nearly tripled in the previous four decades, adult congenital heart disease prevalence has more than doubled in the United States. According to predictions, the frequency of adult congenital heart disease would rise continuously through 2050.

Globally, there are around 50 million ACHD cases. Congenital heart disease refers to a wide range of structural heart disorders and major vessels that are present at birth. Historically, the majority of individuals with congenital cardiac abnormalities had significantly worse survival rates. Congenital heart disease has an estimated incidence of 8/1000 live births, and because to improvements in surgery and interventional cardiology, more than 85 % of these individuals live into adulthood today.

Drug development for the heart, surgery, and interventional techniques have all raced ahead of each other, altering survival as well as the natural course of these diseases. The division of cardiology practice into pediatric and adult cardiologists, as well as the lack of communication between these two specialist groups, has resulted in an increasing number of patients struggling to find optimal care for their conditions as they reach adulthood and are admitted to the hospital with complex problems.

Many people with ACHD have changed cardiovascular physiology as a result of a repaired or untreated complicated abnormality. These patients may react unexpectedly to traditional therapies. The apparently healthy patient may be displaying dangerous results that are only evident to a trained eye.

Commonly discovered congenital heart diseases in adults

Atrial septal defect:

The most frequent type of congenital cardiac disease in adults is atrial septal defect. The prevalence is between 1% and 2%. It is not unusual for an adult cardiologist to discover an ASD in a patient who presents with unusual chest discomfort or palpitations. Other symptoms include difficulty exercising, dyspnea, and, in rare cases, right-sided heart failure, recurrent pulmonary infections, or paradoxical emboli. The most frequent kind of ASD is secundum-type ASD, which accounts for more than two-thirds of all interatrial septum abnormalities.

The use of 3D-TEE guidance and intracardiac echocardiography, as well as post-procedural evaluation of closure devices, contributed to the already-high procedural success with transcatheter closure. Before the introduction of improved non-invasive imaging tools, a shunt of at least 1.5:1 estimated by cardiac catheterization, as well as dilatation of the right heart chambers attributable to considerable left to right shunt, were criteria for closure.

The most crucial question for a cardiologist to address in an adult patient with ASD today should be suitability for transcatheter closure. The primary method for determining closure is echocardiography.

Several issues must be addressed in the management of an ASD patient, which are as follows:

• Right ventricular failure and/or pulmonary hypertension: Enlargement of the right heart chambers indicates a severe ASD. Echocardiography should be used to measure pulmonary artery systolic pressures. A right cardiac catheterization should be conducted, as well as vascular resistance estimates. If considerable pulmonary hypertension is discovered, reversibility should be undertaken. Eisenmenger physiology precludes percutaneous or surgical closure.

If there is significant right atrial enlargement, concomitant Ebstein's abnormalities should be suspected. More than half of individuals with Ebstein's anomaly have patent foramen ovale or ASD.

• The defect's anatomical properties: Is the defect secundum, primum, or high-venosum? Transesophageal echocardiography is often advised and done in cases with unique anatomy and a narrow echocardiographic window.

Partial defective pulmonary venous return may be accompanied by superior or inferior sinus venosus abnormalities. Transthoracic echocardiography may be challenging to identify pulmonary venous return problems.

• After ASD closure, systolic or diastolic dysfunction of the left ventricle (due to ischemia, hypertension, or valvular disease) may result in post-procedural problems. Flow transferred to the right heart through ASD alleviates chronic volume overload on the left ventricle, which has resulted in lower compliance in certain patients.

Because rising left ventricular stiffness and diastolic dysfunction is a typical finding in the elderly, closure should always be approached with caution. In the case of transcatheter occlusion, this could result in a reflection of the volume load back into the pulmonary vasculature, resulting in pulmonary edema.

• Arrhythmias, particularly atrial arrhythmias, are an issue in ASD patients. Patients receiving delayed transcatheter or surgical treatment are more likely to develop atrial arrhythmias. Following correction, 15 to 20% of individuals develop some sort of new-onset supraventricular tachyarrhythmia. Based on the clinical situations, antiarrhythmic medicines, catheter ablation, or surgical maze technique in the same session as surgical correction may be selected.

• Paradoxical emboli: If an ASD is identified in a patient with paradoxical emboli, intervention is warranted regardless of size, unless additional contraindications exist.

Patent ductus arteriosus:

The majority of PDAs are detected and treated during childhood. Interventional cardiologists are now again interested in percutaneous closure.

In many PDA patients, the predominant presenting clinical feature is a mild persistent murmur. This flaw may be discovered by chance during a TTE done for another cause. PDA is often seen in the basal regions of the parasternal short axis window or in the distal half of the aortic arch in the suprasternal window. The closure of a silent PDA is still a source of debate today. According to some researchers, even silent shunts may influence long-term survival and prognosis records during follow-up.

The majority of patients may be closed using interventional procedures; surgery is seldom required and is mostly reserved for significant abnormalities. A severe PDA causes volume overflow, which leads to left ventricular hypertrophy and dysfunction.

Eisenmenger syndrome can occur if big PDAs are overlooked throughout childhood. In this case, correction is not advised. In recent years, endarteritis has become less prevalent. Endarteritis-related aneurysm development is a late complication.

Coarctation of the aorta:

Aortic coarctation (ACo) is a localized constriction in the descending aorta immediately distal to the aortic connection of the ligamentum arteriosum. The amount of stenosis produced by and the segments implicated vary anatomically. 

Although the illness is commonly identified in children, upper extremity hypertension is the most prevalent clinical manifestation in adults. It is critical to remember that ACo is a systemic condition that should not be seen as a simple mechanical impairment.

Hypertension and other vascular effects may continue or reoccur throughout the follow-up of individuals who have undergone correction. Follow-up may include ambulatory blood pressure monitoring (ABPM) and exercise stress testing. Recurrence might appear as a hypertensive response to exercise stress tests or as ABPM results. Aortic coarctation hypertension should be addressed aggressively.

Recoarctation should be detected using both noninvasive and invasive imaging approaches. Aortic coarctation hypertension should be addressed aggressively.

Although echocardiography is an important first diagnostic tool, conclusive diagnosis requires computed tomography/magnetic resonance angiography and/or invasive angiography. Unless there is a contraindication, computerized tomography-angiography is the preferable method.

Upper extremity hypertension, a peak gradient more than 20 mmHg in individuals with or without hypertension, and more than 50% stenosis relative to aortic diameter at the level of the diaphragm suggest a substantial coarctation that requires treatment. Diagnostic criteria and therapeutic indications are the same in individuals who present with recoarctation.

How to treat congenital heart disease in adults?

Fontan procedure:

In a minority of patients with previously repaired CHD, there is a single active pump unit that receives pulmonary venous flow and directs it to systemic circulation. The Fontan technique, also known as cavo-pulmonary circulation, is a surgical bypass of the right ventricle that directs systemic venous blood to the pulmonary circulation. The operation was proposed in the late 1960s in an attempt to give a cure for atretic tricuspid valve.

The traditional procedure is known as atriopulmonary Fontan, and it is associated with complications such as sinus rhythm loss, atrial tachyarrhythmias, and protein-losing enteropathy. Several adjustments have been proposed to address long-term issues. Extracardiac Fontan appears to produce better benefits than atriopulmonary and lateral tunnel variants.

Senning, Mustart Operations (atrial switch) and Jatene (arterial switch) procedure:

Patients who have had previous arterial switch procedures for the somewhat common congenital cardiac disorder known as transposition of great arteries (d-TGA) are another group worth considering.

There are two kinds of TGA. The first form is known as corrected (c-TGA or L-TGA) with discordant atrioventricular and ventriculo-arterial association, and these patients may reach adulthood without evident problems unless they have a concurrent shunt, which is common in these people. The second form is known as d-TGA, and it is life-threatening unless there is a simultaneous left-right shunt.

The surgical method of treatment evolved significantly to its current form, the Jatene operation, which consists of reimplantation of great arteries to their respective ventricles and reimplantation of coronary arteries to neo-aorta.

The previously indicated segmental analysis is critical in identifying anatomy in transposition patients. Venoatrial, atrioventricular, and ventriculoarterial relationships should be carefully assessed and interpreted by expert imagers using appropriate imaging methods.

For over two decades, the Mustard and Senning operations served as the foundation of surgical correction of d-TGA, and many of these patients are now adults. These procedures use the same strategy of constructing a baffle to route blood from systemic veins to the left ventricle and pulmonary veins to the right ventricle. The sole distinction is that, whereas Mustard uses pericardial tissue, the Senning technique uses atrial tissue.

Although survival following Mustard and Senning operations has increased over the previous two decades, the Jatene technique appears to produce superior outcomes (after 20 years, 80 % survival with atrial switch procedures versus 100% survival with Jatene procedure).

Complications associated with Fontan procedure

Clinical manifestations that resemble more prevalent cardiac disorders (e.g., systemic venous congestion owing to right heart failure) should be treated with caution, since response to various therapeutic measures may result in unforeseen consequences:

Atrial arrhythmias:

Atrial arrhythmias and atrial fibrillation are the most common rhythm abnormalities. Atrial fibrillation is a severe issue in atriopulmonary Fontan patients, and it worsens with time. It is hypothesized that the influence of atrial contraction may be advantageous in Fontan circulation, and that sinus rhythm should be preserved if feasible. However, the impact of arrhythmias on morbidity and death is unclear.

Other frequent causes of arrhythmia in adults, including cardiac ischemia, should always be considered. Radiofrequency ablation is possible, but with a high recurrence rate. There were other reports of ventricular arrhythmias and abrupt cardiac death.

Systemic congestion and protein-losing enteropathy:

Other problems include systemic congestion and protein-losing enteropathy. This is attributed to a lack of suction action from active relaxation of the right ventricle and increase of pulmonary venous flow. 

In this circumstance, the impedance of this iatrogenic neoportal system becomes the primary determinant of cardiac output. Therapeutic techniques are being explored to address this significant obstacle to forward circulation in failed Fontan patients. Many individuals with single ventricle physiology who undergo cavo-pulmonary anastomosis may require heart transplantation after a long period of observation.

Pulmonary regurgitation:

In patients undergoing transannular patch repair, pulmonary regurgitation (PR) is more severe and prevalent. When compared to either substantial tricuspid regurgitation or pulmonary hypertension, pulmonary regurgitation was shown to be related with both fatal and nonfatal arrhythmias. 

It is critical that extensive examinations be made in individuals with TOF, and that any associated peripheral pulmonary stenosis be explored. The timing of pulmonary valve replacement in individuals with considerable PR is a critical issue. Proposed indications include right ventricular enlargement as indicated by cardiac MRI, progressive QRS prolongation, progressive symptoms, and left or right ventricular systolic failure.

On a clinical basis, patients react extremely well to pulmonary valve replacement, despite the fact that a meta-analysis indicated that pulmonary valve replacement was not related with substantial improvement in right ventricular ejection fraction.

Recurrent right ventricle outflow tract obstruction:

Echocardiography-measured increases in right ventricular systolic pressures should always prompt cardiac catheterization. The site of stenosis might be infundibular, valvular, or any other distal location. Percutaneous or surgical procedures for distal stenosis may be the preferred therapy. If the right ventricular systolic pressure exceeds 2/3 of the left ventricle systolic pressure, the blockage should be addressed.

Arrhyhthmias:

During follow-up, a wide range of arrhythmias, from atrial fibrillation to supraventricular tachycardias to ventricular tachycardias, may develop. Arrhythmias may also be accompanied with worsening left and/or right ventricular systolic function, exercise intolerance, syncope, or sudden cardiac death, implying an arrhythmogenic cause. Bundle branch block is common in these patients as well. QRS prolongation predicts a poor result and prohibits intervention for valvular disorders.

Main problems associated with atrial and arterial switch procedures

• Baffle leak or obstruction: Most of the time, baffle leaks are restricting, but they become clinically significant when the defect is big or close to a baffle obstruction, resulting in right-to-left shunting.
• Arrhythmia: The manipulation of the atrial chamber during these operations predisposes to nodal dysfunction and atrial arrhythmias. A pacemaker will be required for many people. Although technically challenging, catheter ablation may be a successful choice.
• Due to the relatively thick left ventricular wall in the subpulmonary area, outflow blockage may be noticed. Subvalvular membranes may or may not be present.
• Right ventricular dysfunction: Right ventricular dysfunction is a major source of morbidity in TGA patients and should be actively monitored for early symptoms and signs.

Special considerations in adults with congenital heart disease

Sudden cardiac death:

Sudden Cardiac Death (SCD) is a devastating outcome of ACHD. In a recent autopsy analysis, congenital heart disease was shown to be the cause of SCD in 0.02 % of patients. Recent advancements in telemetric monitoring technologies have allowed for the early diagnosis of arrhythmic events that may otherwise result in SCD.

In adults with congenital heart disease, sudden cardiac death has two major implications. The first, and maybe most essential, is risk classification and primary prevention. The second would be the technical difficulties associated with implanted cardioverter defibrillator (ICD) placement due to lead insertion in surgically altered hearts.

QRS duration and dispersion, as well as temporal variations in these parameters, left ventricle ejection fraction, and subpulmonary ventricular functions, were all predictors of sudden cardiac death in individuals with ACHD. In individuals with maintained ventricular functions, QRS lengthening took the form of generic conduction delay, but in ACHD patients, it took the form of bundle branch block. QRS prolongation was shown to be more fast in patients with systemic or subpulmonary ventricular systolic dysfunction.

Following the implantation of a rhythm device with defibrillator capacity, over one-third of ACHD patients required reintervention. In these individuals, 40% of the ICD shocks administered were considered inappropriate.

Infective endocarditis:

Infective endocarditis (IE) is a major concern in ACHD. In ACHD, IE is a big problem. It's especially crucial in people who have left-to-right shunts that are still present or haven't been addressed. In comparison to prior guidelines on antibiotic prophylaxis, the current European Society of Cardiology guidelines on IE are significantly more permissive. According to these guidelines, the following patient and disease-related considerations warrant prophylaxis:

• The first 6 months following surgical or transcatheter treatment of intracardiac shunts.
• Any residual leak or valvular leak following transcatheter closure of shunts.
• Presence of any type of prosthetic heart valve.
• Any type of cyanotic congenital heart disease.
• Previous history of IE.

Conclusion

A congenital heart defect often called a congenital heart abnormality or congenital heart disease, is a birth disorder in the heart or major vessels. The type of defect determines the signs and symptoms. Symptoms range from non-existent to life-threatening. Rapid breathing, bluish skin, low weight growth, and tiredness are all possible signs when this condition is present. The majority of congenital cardiac abnormalities are not linked to other illnesses. Heart failure is a complication of coronary artery disease.

Major advances in the detection and treatment of congenital heart disease in children have been accomplished in the last 20 to 30 years. As a result, many children with this condition are now able to reach adulthood. Adults with congenital cardiac disease, whether medically treated or uncorrected, are anticipated to be rising at a rate of around 5% per year in the United States alone; this year, there will be almost 1 million such patients.

Drug development, surgery, and interventional procedures for the heart have all raced ahead of each other, affecting survival as well as the natural course of these diseases.