Letter by Albertal and Belardi Regarding Article, “Cardiac Ischemic Preconditioning in Coronary Stenting (CRISP Stent) Study: A Prospective, Randomized Control Trial”
To the Editor:
We read with great interest the article by Hoole et al1 on the protective effect of remote ischemic preconditioning (IP) before percutaneous coronary interventions; however, we are intrigued by the clinical scenario in which the experiment was performed. Precise evaluation of the remote IP hypothesis during percutaneous coronary intervention requires avoidance of potential confounding variables such as the presence of collateral supply2 and the development of coronary IP.3 It is essential to exclude patients with critical or totally occluded lesions because the presence of resting ischemia may trigger IP and/or the development of collaterals. Yet 6.4% of the patients in the study population had lesions with impaired blood flow at rest (ie, Thrombolysis In Myocardial Infarction grade 0 to 2), and 20% had some degree of angiographic collateral flow (ie, Rentrop grade >1). Additionally, ≈17% of patients underwent multisite stenting, which may elicit coronary IP after balloon dilation of the first coronary lesion. Given the fact that balloon predilation can induce IP, which may protect subsequent stent deployment, the authors should report the exact moment at which ischemia was assessed. Finally, development of coronary ischemia during balloon inflation is time dependent, but data on balloon inflation time were not included in the study.