Download How to detect disease at risk in asymptomatic patients Paul Erne

How to detect disease at risk in
asymptomatic patients
Paul Erne
Department of Cardiology
Lucerne, Switzerland
Focus of this presentation
• Detection of disease at risk for sudden cardiac death
(SCD)
• Focus on coronary causes of SCD in young,
asymptomatic patients
• No conflict of interest to declare
Definition of SCD
• Sudden Cardiac Death is an umbrella term used for
many different causes of cardiac arrest.
• Sudden Cardiac Death is defined as an event that is
non-traumatic, unexpected, and resulting from
sudden cardiac arrest within six hours of previously
witnessed normal health without other explanation.
Sharma et al. Br J Sports Med 1997.
Characteristics of SCD in the young
• In the young <35 years:
– Very low incidence: 1/200‘000 per year (≈ 0.005‰)
Maron BJ et al. J Am Coll Cardiol 1998.
– Usually precipitated by physical activity
Maron BJ et al. JAMA 1996.
– Usually no symptoms until SCD occurs
Characteristics of SCD in the young
– SCD still related to episodical physical activity:
Dahabreh IJ et al. JAMA 2011.
Age distribution of sport related SCD in the
young athletes (red) and in the general
population during sport (blue)
Marijon E et al., Circulation 2011.
Characteristics of SCD in the
young- Large spectrum of disease
Only in a minority
of young patients
dying from SCD a
coronary cause may
be found.
Marijon E et al.
Circulation 2011.
Characteristics of SCD in the general
population- Increasing incidence of CAD
Marijon E et al. Circulation 2011.
Marijon E et al., Circulation 2011.
Characteristics of SCD in the young
– Underlying cardiac disease causing SCD is usually
atherosclerotic coronary artery disease, the remainder
due to nonischemic diseases such as HCM or valvular heart
disease.
Corrado D et al. Cardiol Clin 2007.
Magnitude of the problem
• Though incidence of SCD is low in the general
population, absolute numbers of SCD are highest:
Myerburg RJ et al. Circulation 1992.
Magnitude of the problem
• Asymptomatic patients are not routinely seen by the
physician.
 Detection of disease at risk in asymptomatic
patients should start on the population level, but:
Is this feasible?
Technical problems
• 12-lead ECG and exercise ECG
– Usually do not demonstrate abnormalities in patients with
coronary artery anomalies since ischemia in patients with
congenital coronary artery anomalies is episodic.
Basso C et al. J Am Coll Cardiol 2000.
– Too many false positive findings, if used as screening
instrument in a general population.
Erne P et al. Eur Heart J 2007.
Technical problems
• Exercise ECG in SWISSI I
– Subjects with silent ischaemia tzpe I above age 40 without
known CAD referred for life insurance or check-up exams
were eligible to examine effects of anti-ischaemic therapy.
– Of 487 subjects with asymptomatic STdepression during
exercise ECG, myocardial ischemia was verified by stress
echocardiography or perfusion scintigraphy in only 263
patients, corresponding to a false positive rate of 46%.
Erne P et al. Eur Heart J 2007.
Technical problems
• Signal-averaged ECG
– Only evaluated in high risk populations
– Available data on test characteristics suggest that SAECG is
not suitable for screening in a general population:
•
•
•
•
Sensitivity:
Specificity:
Negative predictive value:
Positive predictive value:
63 – 93%
51 – 81%
96 – 99%
10 – 27%
Technical problems
• Coronary CT
– May identify coronary anomalies:
Left coronary artery arising
from the right coronary sinus
– High sensitivity (nearly 100%)
However, costs and
radiation exposure
impede its use as
screening instrument on
the population level.
Technical problems
• Coronary MRI
– Still not suited for the depiction of coronary arteries
– MRI is expensive and availability is limited
Technical problems
• Echocardiography
– May identify coronary anomalies
– Stress echocardiography useful in
detecting the extent of myocardial
ischemia
– However, costs and availabilty limit
its use as a screening instrument
on the population level
Aberrant origin of the left
coronary artery from the rightfacing sinus of Valsalva with
intramural course
Another question
• If we detect coronary artery anomalies or premature
CAD, would we be able to prevent SCD?
SWISSI I
• 54 subjects with silent ischmaemia were randomized
to anti-ischaemic therapy or control of risk factors
and with verified silent ischemia type I
• Follow-up for 10 years
Erne P et al. Eur Heart J 2007.
SWISSI I
• Drug therapy during study:
SWISSI I
• Occurrence of outcome events:
SWISSI I
• Occurrence of outcome events:
– 2 of the 3 cardiac deaths in the risk factor control group
were sudden cardiac deaths
 In patients with silent ischemia type I sudden cardiac
death may be prevented by anti-ischemic drug therapy.
SWISSI II
• Included asymptomatic patients with previous
myocardial infarction and silent ischemia verified by
stress imaging
• 201 patients were randomized to percutaneous
coronary intervention or anti-ischemic drug therapy
• Follow-up for 10 years
Erne P et al. JAMA 2007.
SWISSI II
• During follow-up 12 SCD occurred
• 11 SCD occurred later than 5 years after study start
• 11 SCD in drug therapy group, only 1 in PCI group,
though all patients but one had betablocker
• 8 patients who died from SCD showed signs of
residual myocardial ischemia 4 years after study
start, only 4 were free of ischemia (P = 0.05)
Conclusion from SWISSI I and II
• Anti-ischemic therapy may prevent SCD in
asymptomatic patients with myocardial ischemia
 Screening for coronary anomalies and premature
CAD would be important for the prevention of SCD in
these patients
 What can we do?
Screening for disease at risk
• As shown, screening for disease at risk on the
population level, albeit desirable, is currently not
feasible
• However:
– There is an association of SCD with physical activity
– There is an association of SCD with positive family history
 Screening in selected populations feasible
Screening for disease at risk
• The ESC 2005 and International Olympic Committee
2009 recommend cardiac screening for young
athletes taking part in competitive sport.
• In countries such as Italy, screening participants in
representative sports is mandatory. In some
professions, cardiac testing is also mandatory.
• If there has been sudden death under age 35 in the
family, the family is entitled to be screened.
The International Olympic Commitee
(IOC)Consensus Statement on Periodic Health
Evaluation of Elite Athletes 2009
It has been demonstrated that
adding a 12-lead ECG
examination to history and
physical examination results in
a substantial increase in the
ability to identify potentially
lethal heart disorders (Corrado
et al 2007, Lawless and Best
2008)
Conclusions
• Many cardiac abnormalities predisposing young
persons to SCD may be diagnosed by an ECG, but not
coronary abnormalities or premature CAD.
• Therefore, young persons referred for evaluation of
SCD risk should be examined by echocardiography.
• Screening of young physically active persons should
be propagated in most countries.
• A lot needs to be done: development of new
technologies to better predicting SCD risk