Weaknesses of major randomized trials: they are cleverly designed

against coronary surgery. They are not representative of the daily

practice (highly selected patient population), but their results are

generalized for the whole population with CAD.

RANDOMIZATION IN ARTS TRIAL(Arterial Revascularization Therapy Study) University Hospital Zürich, April-December 1997 5/986 (0.5 %) patients

PTCA61.9%

CABG37.6%

Randomized0.5%

PTCA61.9%

CABG37.6%

Randomized0.5%

STUDY ENROLLMENT IN MAJOR RANDOMIZED STUDIES COMPARING PTCA

TO CABG (91 730 patients) RITA, ERACI, GABI, EAST, CABRI AND BARI trials

Screened95.1%

Enrolled4.9%

Screened95.1%

Enrolled4.9%

It is a well-known fact that patients recruited for trial have better survival

and better results than those eliminated from the trial because of some

exclusion criteria.

NIFEDIPINE IN ACUTE MYOCARDIAL INFARCTION (TRENT TRIAL)

(9292 patients admitted with AMI)

18.2

26.8

6.3

9.36.7

10.2

0

5

10

15

20

25

30

Excluded Placebo Nifedipine

Mortality

Mortalitywith AMI

When analyzing a trial, look carefully at “Material and Methods” section: crucial information explaining the

results might be found there.

Serruys P et al. N Engl J Med 2009;360:961-972

Enrollment and Randomization of Patients with Previously Untreated Three-Vessel or Left Main Coronary Artery Disease in the SYNTAX Trial

2 years, 85 centres:10.6 patients/year

Average number of patients seen by centres in Syntax trial is less than 11 patients/year!

If we accept the fact that “all comers” entered the trial, these centres should have been closed long ago, according to present

standard of PCI and CABG practice.

Serruys P et al. N Engl J Med 2009;360:961-972

Cardiac-Related Medications Given after the Study Procedure

A study with a radically different drug treatment protocols in the two analyzed groups is statistically

invalid.

Difference in outcome in trials funded by for-profit and not-for-profit sources

JAMA 2006; 295(19):2270-4

49

3540

5057 55 54

6967 67 66

82

0

20

40

60

80

100

% p

ositi

ve

Not for profitMixedFor profit

p for trend < o.oo5

Beware of industry sponsored trials! Results very often meet the

sponsor’s expectations!

CABG MORTALITY RATES AMONG DIFFERENT SURGEONS: A PROSPECTIVE STUDY

JAMA 1991;266:803-809

There is a major difference between swallowing a pill and performing a complex operation; this fact is not

appreciated by statisticians.

Survival with CABG @ 3 years is 28.4 % higher!

Hannan E et al. N Engl J Med 2005;352:2174-2183

Non-randomized observational trials can reach very important results, which are

presently ignored by the academia schooled in conventional statistics