Severe adult congenital heart disease
(CHD) shot up by 85% in just 15 years, according to
a new Canadian study. That may not sound like good news
on the surface, but the McGill researchers say the glass
is definitely half-full. If a higher percentage of the
population is afflicted with the birth defect, fewer
children with severe CHD lesions are dying, they argue.
And that means the medical community has advanced by
leaps and bounds in both the diagnosis and treatment
of the most serious forms of CHD — in just a few
decades.
LIVING
LONGER
Proof of the increase came as no surprise to Dr Ariane
Marelli, director of the McGill Adult Unit for Congenital
Heart Disease Excellence. Her study, published online
ahead of print in Circulation on January 8, is
the first ever to look at the change in prevalence of
CHD over time in both children and adults.
"We are seeing more patients, and
more complex patients," said Dr Marelli, who has been
treating adults with CHD since the mid-90s. For the
first time ever, there are now nearly as many adult
CHD patients as children. The increase in prevalence
is expected to continue for some time before levelling
off, she said.
This sea change in the life expectancy
of children with CHD is mostly due to the great strides
made in heart surgery practices and technology since
the 1980s. Also, diagnoses of difficult-to-find, more
benign forms of CHD are now easier to make before birth
thanks to fetal cardiac ultrasound technology, which
was developed in the 80s and dispersed widely since.
The bottom line is that doctors are now far better prepared
to deal with children born with any kind of CHD.
NEW
CHALLENGES
News of Dr Marelli's results travelled fast in the small
community of Canadian adult CHD specialists. "It's kind
of comforting, in a way," said Dr Carin Wittnich, director
of U of T's Cardiovascular Sciences Collaborative Program,
who was not affiliated with the study. "It suggests
that research and clinical care have collaborated for
success."
But the good news must be tempered
by the knowledge of a new set of challenges. "We are
victims of our own success," admitted Dr Wittnich. "Although
we have made progress, we now have new patient populations
to help. But isn't it nice to know we can get them [child
CHD patients] there, leading productive lives? Now we
need to look at their unique needs."
According to Dr Marelli, the consequences
of a history of severe CHD lesions on adults are largely
undocumented scientifically. It's believed there is
an elevated risk of arrhythmia, heart failure (specifically
of the right ventricle) and pulmonary hypertension.
MEDICAL
MURMURS
Dr Marelli said the rise in adults living with CHD isn't
the only side effect of the successes at diagnosing
and treating the disease in children. Because echocardiography
has allowed cardiologists to diagnose fetal heart defects
in utero, for example, there have been a number
of cases in which pregnancies have been aborted, she
said.
As well, the increase in female
CHD patients reaching adulthood presents a new problem.
"CHD is largely acquired through genetic transmission,"
Dr Marelli explained. "That may be a factor if women
are surviving to become mothers."
Dr Judith Therrien, president of
the Canadian Adult Congenital Heart Network, agreed:
"The incidence of child abnormalities in a fetus is
about 1-2% in the general population. In CHD women,
it is 6% — three times higher, but still small."
Obstetricians must be vigilant, she said, if a pregnant
patient had treatment for CHD and should order a fetal
cardiac ultrasound right away.
CARDIAC
CAREFUL
Although adult CHD is a highly specialized field, there
are some things that GPs need to know about the new
trend towards older CHD patients. "If you come across
someone who had a cardiac operation at a young age,
you immediately should refer to an adult CHD clinic
for at least one assessment," said Dr Therrien. The
same goes for a patient who presents with heart problems
who had a diagnosis of a murmur as a child but may not
have been diagnosed with CHD. "At least a third have
severe pathologies and need followup," Dr Therrien warned.
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