Letter by Attaran Regarding Article, “Cardiac Ischemic Preconditioning in Coronary Stenting (CRISP Stent) Study: A Prospective, Randomized Control Trial”
To the Editor:
Hoole et al1 should be commended for their study of remote ischemic preconditioning in patients undergoing percutaneous coronary intervention. In this prospective, randomized, controlled, single-center trial, the authors found that the remote ischemic preconditioning group showed an attenuated serum troponin rise 24 hours after percutaneous coronary intervention, reported less chest pain during the procedure, demonstrated fewer ST-segment changes on ECG during balloon inflation, and, above all, appeared to show fewer major adverse cardiac and cerebral events at 6 months.
Most of the major adverse cardiac and cerebral events in the control group were attributed to readmission for acute coronary syndromes. In the remote ischemic preconditioning group, we note that 77% of stents deployed were drug-eluting stents versus 67% in the control group. This difference is not statistically significant (P=0.16), of course, but could this explain some of the study findings?
Chest pain during cardiac catheterization was also evaluated. Did the patients receive any narcotics or anxiolytics before or during the case? If so, were the doses comparable between groups?
Finally, do the authors believe that there may be a placebo effect? The patients who received blood pressure cuff inflation were aware of it. Might this play a role in at least the patient-subjective portion of the study, namely, the reported chest pain?