[Reduction of myocardial infarction size after primary percutaneous coronary intervention].

Background: Achieving reperfusion as soon as possible is essential in order to reduce myocardial infarction size and thus improve prognosis. An increasing number of patients with myocardial infarction are treated with primary percutaneous coronary intervention (PCI). Technetium 99m-tetrofosmin myocardial perfusion tomography (SPECT) is a valid test for assessing myocardium at risk and final infarct size expressed by a hypoperfusion index (HPI) of the left ventricular mass.
Material and Methods: 20 patients with acute ST-elevation myocardial infarction were treated with primary percutaneous coronary intervention within six hours of onset of symptoms. Myocardium at risk and final infarct size were assessed by Technetium 99m-tetrofosmin immediately before and a few hours, one week and six weeks after.
Results: The hypoperfusion index immediately before percutaneous coronary intervention was 31%, four to six hours after PCI 25%, one week later 16% and six weeks later 12%, i.e. a relative reduction of 60% (p < 0.01). Anterior wall infarctions had a higher level of myocardium at risk before primary PCI compared to inferior wall infarctions (36% vs. 24%), but anterior wall infarctions had a higher salvage index compared to inferior wall infarctions.
Interpretation: This non-controlled study shows a marked reduction in final infarction size in patients with acute ST-elevation myocardial infarction treated with primary PCI.