Author + information
- Nathan Mewton, MD, PhD⁎ (, )
- Pierre Croisille, MD, PhD,
- Eric Bonnefoy-Cudraz, MD, PhD and
- Michel Ovize, MD, PhD
- ↵⁎Hôpital Cardiovasculaire Louis Pradel, Cardiology Department, 28 Avenue Doyen Lépine, 69677 Lyon, France
We read with interest the report by Yamashita et al. (1) regarding the noninvasive assessment of coronary “perfusion” by contrast-enhanced coronary multidetector computed tomography (MDCT) during the acute phase in patients with ST-segment elevation myocardial infarction (STEMI) before therapeutic reperfusion.
This pioneering study demonstrates that contrast-enhanced MDCT can be performed within 20 min in patients with STEMI at an experienced institution to evaluate coronary perfusion, with good levels of accuracy. In their study, Yamashita et al. (1) showed that pre-reperfusion contrast-enhanced MDCT is feasible, with a door–to–invasive coronary angiography time of about 78 min. The door-to-balloon time is not provided by the investigators in the report but should therefore have been approximately 90 min, the “target” time set by the most recent guidelines (2).
As such, this study seems to contradict the guideline that timely reperfusion be performed in patients with STEMI (2). Yamashita et al. (1), as well as the editors of iJACC, have decided to open the debate over the “time is muscle” paradigm. It is true that it would be very difficult to show what amount of myocardium would be irreversibly damaged in the final 20 min of a 4-h to 5-h ischemic period, accounting for the many factors that influence final infarct size (3). In our opinion, it would be of interest to discuss the position of the investigators and editors on this specific question, which is not discussed in this report. This question is a sensitive one in the cardiology community, in which the opinion that a delay in reperfusion is in conflict with optimal patient care, is shared by many.
The study further opens the door to the important potential of cardiac MDCT in the acute phase of infarction. Beyond its capacity to assess coronary perfusion before angioplasty, cardiac MDCT could be a very powerful tool to assess the myocardial area at risk. The accurate assessment of this major determinant of infarct size is essential to all therapeutic studies investigating new reperfusion therapies to increase myocardial salvage and improve patient outcomes (4). This question is important, because the other clinically available imaging methods to assess the myocardial area at risk (single photon-emission computed tomography, T2-weighted cardiac magnetic resonance) are not considered definitive standards and have well-known limitations. With respect to this issue, it would be interesting to know whether Yamashita et al. (1) also assessed myocardial perfusion at the tissue level in this cohort of patients.
Cardiac contrast-enhanced MDCT offers the potential of a widely available and relatively safe noninvasive imaging method to assess STEMI. The current and future applications of the present method must be framed so as to control the absence of adverse effects in study patients but offer promising perspectives to better understand and explore STEMI.
- American College of Cardiology Foundation
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