8: Adult congenital heart disease

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TOPIC 8 Adult congenital heart disease

Genetic and non-genetic associations with congenital heart disease 69

Atrial septal defect (ASD) 70

Types of ASD 70

Ostium secundum defect 70

Ostium primum defect 70

Sinus venosus defect 70

Coronary sinus ASD 70

Clinical features 71

Indications for closure 71

Patent ductus arteriosus (PDA) 72

Clinical features 73

Coarctation of the aorta 73

Clinical features 73

Bicuspid aortic valve 74

Subvalvular aortic stenosis 75

Supravalvular aortic stenosis 75

Pulmonary stenosis 75

Ebstein anomaly 76

Tetralogy of Fallot 76

Palliative procedures 77

Corrective surgery 77

Transposition of the great arteries (D-transposition of the great arteries) 78

Presentation 78

Subsequent surgical strategies 78

Long term complications 79

Congenitally corrected transposition of the great arteries (L-transposition of the great arteries) 79

Clinical features 79

Cyanotic congenital heart disease 81

Univentricular physiology 82

Tricuspid atresia 82

Hypoplastic left heart 82

Double inlet left ventricle 82

Complications of the Fontan/TCPC circulation 84

Genetic and non-genetic associations with congenital heart disease

Genetic

Table 8.1 Genetic syndromes associated with congenital heart disease

Syndrome	Typical genetic defect	Typical cardiac defects
Down syndrome	Trisomy 21	Atrioventricular septal defect, VSD, ASD, PDA
Holt–Oram syndrome	12q2	ASD, VSD
Turner syndrome	XO	Aortic coarctation, bicuspid aortic valve
Noonan syndrome	12q	Pulmonary stenosis, hypertrophic cardiomyopathy
Di George syndrome	22q11 deletion	Truncus arteriosus, tetralogy of Fallot, interrupted aortic arch
Williams syndrome	7q11 deletion	Supravalvular aortic stenosis, peripheral pulmonary artery stenosis

Non-genetic

Table 8.2 Non-genetic associations with congenital heart disease (known or suspected maternal factors)

Infective	Rubella, toxoplasmosis, Coxsackie B virus
Environmental	Trichloroethylene, dichloroethylene, chromium
Iatrogenic	Antiepileptics, lithium, thalidomide, warfarin, isotretinoin
Lifestyle	Alcohol and illicit drug use, low folate intake
Medical	Diabetes mellitus, phenylketonuria

Atrial septal defect (ASD)

Communication between the atrial chambers allowing mixing of blood.

Types of ASD (Figure 8.1)

Ostium secundum

Sinus venosus defect

Coronary sinus ASD.

Figure 8.1 Schematic demonstrating anatomical locations of inferior sinus venosus ASD. TV, Tricuspid valve.

Ostium secundum defect

May present in adulthood with first occurrence of symptoms.

Defect in the area of fossa ovalis. May be amenable to transcatheter closure.

Ostium primum defect

This is part of a spectrum of atrioventricular septal defects, resulting from defective fusion of the inferior and superior endocardial cushions, leading to a common atrioventricular junction. Associated atrioventricular valve, atrial septal and ventricular septal anomalies can occur within this spectrum.

Associated with Down syndrome.

Definitive management is surgical. Repaired patients may present later with left atrioventricular valve regurgitation or, less commonly, left ventricular outflow tract obstruction.

Sinus venosus defect

The defect lies in the majority of cases at the mouth of the superior vena cava (superior sinus venosus) and is frequently associated with anomalous drainage of the right upper pulmonary vein into the right atrium. Rarely the defect lies next to the inferior vena cava (inferior sinus venosus).

Definitive management is surgical.

Coronary sinus ASD

At least part of the wall between the coronary sinus and LA is absent. Often associated with a persistent left superior vena cava. Similar clinical course to secundum ASD, also dependent on size of defect and shunt.

Definitive management is surgical.

Clinical features

May be asymptomatic and discovered incidentally, but symptoms appear increasingly with age. Presentation includes:

Atrial fibrillation, atrial flutter, sick sinus syndrome

Right heart volume overload/right heart failure

Exertional dyspnoea

Recurrent chest infection

Paradoxical emboli

Pulmonary hypertension (ASD is associated with pulmonary hypertension though there is not thought to be a direct causal relationship)

Indications for closure

Right heart volume overload

ASD minimum diameter 10 mm

Left to right shunt > 1.5:1

Paradoxical emboli.

Before closure need to assess for: presence of significant pulmonary hypertension (precludes closure), presence of significant mitral valve disease (severity may be underestimated and may cause decompensation following closure).

The prognostic benefit of closure is reduced with increased age, though this does not preclude intervention. Delayed closure is associated with an increased risk of long term complications including atrial arrhythmias and reduced survival.

Ventricular septal defect (VSD)

Types of VSD

Membranous (perimembranous/infracristal)

Beneath crista supraventricularis, posterior to papillary muscle of conus, beneath aortic valve

Associated tricuspid valve abnormalities.

Outlet (supracristal/infundibular/doubly committed subarterial)

Located between crista supraventricularis and pulmonary valve. Right coronary cusp of aortic valve may prolapse into VSD leading to aortic regurgitation/subpulmonary stenosis.

Inlet

Defect in central fibrous body between tricuspid and mitral valves.

Often associated defects.

Muscular

Often multiple; in muscular septum.

Clinical features

Clinical features depend upon the anatomy and haemodynamic severity of the VSD and presence of associated anomalies.

VSDs can be classified according to haemodynamic effect. The measured variables are the pulmonary artery: aortic systolic pressure ratio and pulmonary blood flow: systemic blood flow ratio.

Small: Pressure ratio < 0.3 and flow ratio < 1.4

Moderate: Pressure ratio > 0.3 and flow ratio 1.4 to 2.2

Large: Pressure ratio > 0.3 and flow ratio > 2.2

Eisenmenger: Pressure ratio > 0.9 and flow ratio < 1.5

Where the right ventricular systolic pressure is lower than left ventricular systolic pressure, in the absence of right ventricular outflow tract obstruction, the VSD is termed “restrictive”

Adults may have a small unrepaired VSD, a repaired VSD or Eisenmenger syndrome. Moderate or large VSDs are likely to have been repaired in childhood. Haemodynamically significant VSDs can lead to left heart pressure loading, right heart volume loading, pulmonary vascular disease and Eisenmenger syndrome.

Other complications include:

Infective endocarditis.

Aortic regurgitation due to aortic cusp prolapse (outlet VSD and membranous VSD).

Arrhythmia: Atrial fibrillation may occur with left atrial dilatation secondary to left heart volume overload. Ventricular arrhythmia and late sudden death are reported.

Right ventricular outflow obstruction. It may take the form of a ‘double chamber right ventricle’ in which muscular bands divide the right ventricle into a high-pressure proximal chamber and lower pressure distal chamber.

Indications for adult intervention include:

Significant left to right shunt (Qp/Qs > 2)

Pulmonary artery systolic pressure > 50 mmHg. If the pulmonary artery pressure (or arteriolar resistance) is greater than 2/3 systemic arterial pressure (or arteriolar resistance), there must be evidence of a net left to right shunt of ≥ 1.5 or evidence of reactivity or potential reversibility (assessment with pulmonary vasodilator or lung biopsy).

Ventricular dysfunction (left ventricular volume overload or right ventricular pressure overload)

Aortic cusp prolapse with greater than mild aortic incompetence

Significant right ventricular outflow tract obstruction (mean gradient > 50 mmHg).

Patent ductus arteriosus (PDA)

The ductus arteriosus allows oxygenated blood to pass from the placenta to the aorta, bypassing the lungs in utero. The pulmonary end is situated just left of the bifurcation of the main pulmonary artery and connects to the descending aorta, distal to the left subclavian artery. It normally closes shortly after birth. Persistence of the ductus is associated with congenital rubella and is more common after premature birth. It may be present with other cardiac anomalies and in some cases is essential for survival.

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