On 2014 Sep 29, Preben Berthelsen commented:

Before accepting the authors’ results it must be realized that the conclusions are based on a non-randomised, unplanned post hoc subgroup analysis of a larger study on remote ischaemic preconditioning in CABG surgery (ClinicalTrials NCT01406678). The results of the primary study were published in the Lancet (August 17, 2013). In the Lancet paper there is illuminating information on the present paper. The authors state that “After use in some patients, however, we became aware of apparent interference of propofol with remote ischaemic preconditioning and discontinued its use in the remainder of the study”. In my opinion this indicates that this is a case of betting after the race.

The authors have not statistically compared the difference in troponin release between the propofol and the isoflurane group. Their conclusions are instead solely based on within group statistical analyses. And as Bland & Altman lucidly put it “this approach is biased and invalid, producing conclusions which are potentially highly misleading” (Trials 2011,12:264).

Taken in all, I feel it justified to view the results of this paper with some scepticism. P.G.Berthelsen, Charlottenlund, Denmark.

On 2014 Sep 29, Preben Berthelsen commented:

Before accepting the authors’ results it must be realized that the conclusions are based on a non-randomised, unplanned post hoc subgroup analysis of a larger study on remote ischaemic preconditioning in CABG surgery (ClinicalTrials NCT01406678). The results of the primary study were published in the Lancet (August 17, 2013). In the Lancet paper there is illuminating information on the present paper. The authors state that “After use in some patients, however, we became aware of apparent interference of propofol with remote ischaemic preconditioning and discontinued its use in the remainder of the study”. In my opinion this indicates that this is a case of betting after the race.

The authors have not statistically compared the difference in troponin release between the propofol and the isoflurane group. Their conclusions are instead solely based on within group statistical analyses. And as Bland & Altman lucidly put it “this approach is biased and invalid, producing conclusions which are potentially highly misleading” (Trials 2011,12:264).

Taken in all, I feel it justified to view the results of this paper with some scepticism. P.G.Berthelsen, Charlottenlund, Denmark.