Adult Congenital Heart Disease (ACHD)

An increasing number of children with congenital heart disease are surviving into adulthood due to greatly improved surgical, medical, anaesthetic and intensive care over the last few decades. The survival of congenital patients into adulthood is now more than 90% in comparison to the 25% survival rate around fifty years ago. As this new group of patients enters adulthood, they will need regular monitoring and ongoing care, and sometimes may even require further surgical interventions.

With the exception of a few procedures – ligation of isolated patent ductus arteriosus (PDA), closure of isolated atrial septal defects (ASD) and ventricular septal defects (VSD) – surgical treatment of congenital heart disease is more often palliative than curative. Repeated procedures and interventions are the norms as conduits, baffles, shunts and grafts become narrowed, blocked and incompetent with time. In addition to the medical and surgical issues, this growing population may also face specific social, psychological and behavioural problems throughout their life.

The timely establishment of adult congenital heart disease (ACHD) (also known as congenital heart disease in adults) as a subspecialty of cardiology will help people living with ACHD to improve their quality of life.

Congenital Heart Defects Classification

Blood circulation in a normal heart.

There are many types of congenital heart defects and these can be classified into four main categories:

1. Right to left shunts/ Cyanotic heart defects
   The heart is made up of four chambers – two on the left and two on the right. Typically, the left and right side of the heart are separate from each other. The left side of the heart delivers oxygen-rich blood from the lungs to the body while the right side of the heart receives oxygen-poor blood from the rest of the body and transports it to the lungs.
   
   However, in right to left shunts, an unusual link between the right and left sides of the heart causes blood to flow from the right to left side of the heart. This reduces the amount of oxygen in the blood circulating in the body, resulting in a bluish tint to the skin (cyanosis).
   • Tetralogy of Fallot
   • Ebstein’s anomaly
   • Pulmonary atresia
   • Tricuspid atresia
     
   
   
2. Left to right shunts
   In left to right shunts, there is an unusual link between the right and left sides of the heart which causes blood to flow from the left side of the heart to the right. This results in an excess amount of blood in the right side of the heart and as such, excessive blood flow to the lungs.
   
   • Patent Ductus Arteriosus (PDA)
   • Atrial septal defect
   • Ventricular septal defect
   • Atrio-Ventricular defect
   • Aorto-pulmonary window
     
   
   
3. Blood flow obstruction
   These are conditions where faulty heart valves or blood vessels block the flow of blood in or out of the heart.
   • Mitral valve stenosis
   • Coarctation of Aorta
   • Congenital pulmonary stenosis
   • Congenital aortic stenosis
   • Interrupted aortic arch
   
   

​Some patients do not show signs or symptoms of congenital heart disease until adulthood. These symptoms include:

• Fatigue
• Abnormal heart rhythm (arrhythmia)
• Breathlessness
• Swelling of organs and body tissues
• Blueness in the fingernails, skin and lips
  

The incidence of congenital heart disease (CHD) in Singapore was 0.81% of total live births based on the birth defect registry from 1994-2000 but this has increased to 0.97% in 2021. In Singapore, with an estimated population of around 4.3 million, the estimated number of adults with CHD would be in the region of 12,000 adults with an extra 300-320 cases added annually, assuming an annual birth of 37,000 – 40,000 newborns. It is estimated that in the next decade, the number of adult patients with congenital heart disease worldwide will exceed their paediatric counterparts.

Challenges

Despite their improved life expectancy, congenital patients stepping into adulthood face many issues:

• They have limited understanding of their underlying congenital defects
• Many believe that they are ‘cured’, unaware of possible sequel from their surgery and the need for further surgical procedures
• Medical and surgical issues which require life-long follow up, regular check-ups and repeated investigations and evaluation
  
• Potential complications such as heart failure, abnormal heart rhythm (arrhythmia) or pulmonary hypertension
• Issues related to pregnancy, contraception, risk to offspring that need to be discussed
• Risk of endocarditis and the need for antibiotic prophylaxis
• Management of associated non-cardiac medical problems
• Social, emotional, financial, vocational, educational, psychological and lifestyle issues specific to each individual. As they enter adulthood, ACHD patients need to take charge of their lives, substituting parental overprotection in childhood with a sense of responsibility and maturity of their own

In the past, these adult patients were usually managed by paediatric cardiologists who, although excellent in interpreting and comprehending the underlying physiology and haemodynamics, were nonetheless ill-equipped in managing adult related problems like coronary artery disease, pregnancy and contraception, arrhythmias, hypertension. Research has shown that ACHD patients especially those of moderate to severe complexity do better when their care is centralised to a dedicated specialised ACHD unit.

Having survived into adulthood, ACHD patients are now facing a new set of challenges encompassing not only medical or surgical problems but extending to psychological, vocational and lifestyle issues. Congenital heart disease is a heterogeneous condition with a wide spectrum of varying complexity and severity. Therefore, all ACHD patients (with the exception of those with mild isolated valvular heart disease or those with repaired patent ductus arteriosus, ventricular septal defect and atrial septal defect) should be followed up in a specialised ACHD unit with a dedicated multidisciplinary team who can anticipate the various issues particular to each individual. Only then can we provide adequate care and work towards improving the clinical outcome of this special group of patients.

Diagnosis typically starts with a physical examination by a doctor, assessing your medical history and routine tests. Other tests recommended may include:

• Electrocardiogram (ECG)
• Exercise Stress Test
• Echocardiogram
• Cardiac catheterisation
• Chest Radiograph (X-ray)
• Cardiac Magnetic Resonance Imaging (CMR)
• Cardiac Computed Tomography (CT scan)
• Transoesophageal echocardiogram (TEE)
  

NHCS Adult Congenital Heart Disease (ACHD) Programme

This programme was first started in 2003 and currently offers:

• ACHD clinic on every Wednesday and Thursday afternoon, and on the first and third Fridays of the month in which an average of 20-30 patients are seen at each session. Besides offering care and follow up of ACHD patients, NHCS also does screening of suspected Marfan patients; close monitoring of ACHD patients during pregnancy (see Pregnancy and Women with CHD) and a monthly joint Cardiac Obstetric Clinic (every last Monday of the month) with obstetricians from Singapore General Hospital (SGH); Monthly Transition Clinic in KK Women's and Children's Hospital (KKH) run jointly with paediatric cardiologists from KKH for patients above the age of 16. The aim is to give paediatric patients a smooth transition from paediatric cardiology to adult cardiology services. An average of 100-150 teenagers with congenital heart disease are transferred from KKH to NHCS every year. There is also a monthly Pulmonary Hypertension Clinic (every second Friday of the month) run jointly with a respiratory physician and a rheumatologist from SGH for general as well as congenital patients with severe pulmonary hypertension.
• Dedicated twice weekly congenital echocardiography sessions.
• Dedicated weekly congenital cardiac catheterisation and intervention (particularly ASD, patent foramen ovale (PFO) and PDA device closure).
• Surgical interventions including extra-cardiac Fontan procedures for uni-ventricular hearts, pulmonary homograft replacements for Tetralogy of Fallot patients with severe pulmonary regurgitation, Rastalli conduit for patients with pulmonary atresia.
  
• Expertise in nuclear imaging, magnetic resonance imaging (MRI) and multi-slice computed tomography (CT) imaging.
• Expertise in pacing, arrhythmia treatment and ablation in congenital patients.
• Expertise in cardiopulmonary and exercise testing.
• Expertise in heart and lung transplantation for selected patients with end-stage congenital heart disease.
• Dedicated ACHD nurse for education, support and care of ACHD patient and their families.
  

Adult Congenital Heart Disease (ACHD) Clinic

This clinic looks after patients with operated as well as unoperated congenital heart conditions from age 16 onwards. Adults with congenital heart disease need regular monitoring and sometimes further surgical interventions. It also screens suspected Marfan patients and monitors ACHD patients closely during pregnancy.

For more information on NHCS Adult Congenital Heart Disease (ACHD) Programme, visit here.