CARDIOLOGISTS IN H S R LAYOUT BANGALORE
Cyanotic congenital heart disease
Some of the more common cyanotic lesions are discussed below. There are, however, a number
of problems common to patients with cyanotic heart disease.
1 Erythrocytosis. Chronic cyanosis causes an increase in red cell numbers as a way of increasing
oxygen carrying capacity. The platelet count is sometimes reduced and the white cell
count normal. The increased blood viscosity associated with the high red cell mass causes
a slight increase in the risk of stroke.37 Most patients have a stable elevated haemoglobin
level, but venesection is recommended if this is greater than 20 g/dL and the haematocrit is
greater than 65%. Levels as high as this can be associated with the hyperviscosity syndrome:
headache, fatigue and difficulty concentrating. Recurrent venesection can cause iron depletion
and the production of microcytic red cells, which are stiffer than normal cells and so
increase viscosity further.
2 Bleeding. Reduced platelet numbers, abnormal platelet function and clotting factor deficiencies
mean these patients have an increased risk of haemorrhage. The most dangerous
problem is pulmonary haemorrhage but bleeding from the gums and menorrhagia are more
common. The use of anticoagulation must be restricted to those with a strong indication
3 Gallstones. Chronic cyanosis and increased haem turnover are associated with an increased
incidence of pigment gallstones.
4 Renal dysfunction and gout. Congestion of the renal glomeruli is associated with a reduced
glomerular filtration rate and proteinuria. This and the increased turnover of red cells lead
to urate accumulation and gout.
5 Pulmonary hypertension. Lesions associated with increased flow through the pulmonary
circulation (e.g. a large atrial septal defect) can lead to a reactive rise in pulmonary arterial
resistance. This is more likely to occur if the left to right shunt is large. Eventually these pulmonary
vascular changes become irreversible, pulmonary pressures equal or exceed systemic
pressures, and central cyanosis occurs because the intra-cardiac shunt reverses (Eisenmenger’s
syndrome). Flow is now from right to left. There is then no benefit in attempting to correct
the underlying cardiac abnormality.
Earlier and more successful treatment of children with congenital heart disease has
reduced the number of patients with this inexorable disease. Careful management of these
conditions can nevertheless improve patients’ symptoms and survival.
Reasonable exercise tolerance is usually maintained into adult life for most patients but
progressive deterioration then occurs. Haemorrhagic complications, especially haemoptysis,
are common. Thrombotic stroke, cerebral abscess and pulmonary infarction can also occur.
364 PRACTICAL CARDIOLOGY
In a recent European survey, survival for patients with simple defects and Eisenmenger’s
was to 32.5 years, but only 25.8 years for those with Eisenmenger’s resulting from complex
There is a 50% maternal mortality risk with pregnancy. Quite minor surgical procedures
are associated with high risk.
Trials with endothelin antagonists are being conducted and continuous oxygen treatment
can provide symptomatic relief. Lung and heart lung transplant should be considered
for some of these patients.
6 Endocarditis. Most patients with congenital heart disease have a lifelong risk of infective
endocarditis. Constant reminders of this risk should be given to the patients and their usual
doctors. As well as appropriate antibiotic prophylaxis . before procedures, a high
index of suspicion is very important. A febrile illness should not be treated with antibiotics
until at least two sets of blood cultures have been taken. Early referral