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Weaknesses of major randomized trials: they are cleverly designed against coronary surgery. They are not representative of the daily practice (highly selected.

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Presentation on theme: "Weaknesses of major randomized trials: they are cleverly designed against coronary surgery. They are not representative of the daily practice (highly selected."— Presentation transcript:

1 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.

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

3 STUDY ENROLLMENT IN MAJOR RANDOMIZED STUDIES COMPARING PTCA TO CABG (91 730 patients) RITA, ERACI, GABI, EAST, CABRI AND BARI trials

4 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.

5 NIFEDIPINE IN ACUTE MYOCARDIAL INFARCTION (TRENT TRIAL) (9292 patients admitted with AMI)

6 When analyzing a trial, look carefully at “Material and Methods” section: crucial information explaining the results might be found there.

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9 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

10 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.

11 Serruys P et al. N Engl J Med 2009;360:961-972 Cardiac-Related Medications Given after the Study Procedure

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

14 Difference in outcome in trials funded by for-profit and not-for-profit sources JAMA 2006; 295(19):2270-4

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16 Beware of industry sponsored trials! Results very often meet the sponsor’s expectations!

17 CABG MORTALITY RATES AMONG DIFFERENT SURGEONS: A PROSPECTIVE STUDY JAMA 1991;266:803-809

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19 There is a major difference between swallowing a pill and performing a complex operation; this fact is not appreciated by statisticians.

20 Survival with CABG @ 3 years is 28.4 % higher! Hannan E et al. N Engl J Med 2005;352:2174-2183

21 Non-randomized observational trials can reach very important results, which are presently ignored by the academia schooled in conventional statistics


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