Original title: Preinfarction Angina Reduces Infarct Size in ST-Elevation Myocardial Infarction Treated With Percutaneous Coronary Intervention Reference: Ronald Reiter et al. Circ Cardiovasc Interv. 2013;6:00-00.

Ischemic preconditioning (IPC) is a phenomenon whereby transitory ischemia episodes protect the myocardium against a more prolonged episode. 

Until now, IPC has been the most effective approach to protect the myocardium. Pre infarction angina is a clinical surrogate of IPC and has been associated with reduced infarct size in patients that receive thrombolytic therapy; however this is not conclusive for patients treated with primary angioplasty.

245 patients with ST elevation myocardial infarction treated with primary angioplasty were analyzed; 79 of these patients had presented angina 24 hours before admition vs. 166 patients without pre infarction angina. There were no significant differences in the rest of baseline characteristics between both groups.

For the patients with previous angina, both infarct size and troponin peak was significantly reduced (p<0,0001) despite having identical ischemic times and angiographic results. Ejection Fraction was 4$ lower in patients with preconditioning (51,4±1,1% vs. 47,5±1%; p=0,02).

Conclusion 

This study is the most detailed analysis carried out so far on the potential protective effect of ischemic preconditioning in patients with ST elevation myocardial infarction treated with primary angioplasty.

Editorial Comment

Randomized studies on ST elevation acute coronary syndromes should start considering pre infarction angina among key variables, seeing that this could be an important confounder, mainly if infarct size is one of the primary concerns. A good example of this is the large number of trials assessing the use of thrombi aspiration.

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