Mobilization of Endothelial Progenitor Cells Following Alcohol Septal Ablation in Hypertrophic Obstructive Cardiomyopathy: Randomized Controlled Trial of Aspirin

Aspirin has been shown to lower the number of EPCs in a time- and concentration-dependent manner. In vitro studies also show that aspirin may reduce the migratory and adhesive capacity of isolated EPCs, inhibit iNOS and tubule formation, which are pre-requisites for angiogenesis. This is relevant when patients are given a loading dose of 325mg at the time of diagnosis of acute myocardial infarction where higher numbers of EPCs have been associated with better outcomes. Furthermore, in the PLATO (Platelet Inhibition and Patient Outcomes) trial, high dose aspirin appeared to counteract the beneficial effect seen when ticagrelor or clopidogrel was used with low doses of aspirin in acute coronary syndromes (ACS).

As aspirin is currently standard of care in the management of ACS, it is difficult to conduct a study of the effect of aspirin versus placebo in that scenario. However, during alcohol septal ablation for hypertrophic obstructive cardiomyopathy, the indication for an antiplatelet agent is not well defined and varies between operators. When a small amount of myocardium is deliberately destroyed in this process, it serves as an ideal model to study the effect of aspirin on the biology of EPCs in vivo. This could provide an explanation to the different effects of high versus low dose aspirin when combined with a second antiplatelet agent in the management of ACS.