001 Thromboaspiration before primary PCI in STEMI patients reduces infarct size, but not microvascular obstruction: a magnetic resonance imaging study

Abstract

Thromboaspiration (TA) during primary percutaneous intervention (PCI) is effective in opening infarct related artery (IRA) in patients (pts) with ST elevation acute myocardial infarction (STEMI), leading to better reperfusion and outcome. Microvascular obstruction (MVO) after successful IRA revascularization is associated with greater myocardial damage, left ventricular (LV) impairment and higher mortality. We evaluated relationships between (i) TA and MVO 5 days after STEMI; (ii) TA and infarct size at 5 days and 6 months; (iii) TA and LV remodelling at 6 months. 51 pts aged <75, with first STEMI and totally occluded IRA, referred for primary PCI within 12 hours of onset of symptoms were enrolled. All pts underwent TA before stenting. Pts were categorized according to positive or negative TA. MVO, infarct size and remodelling were assessed by contrast-enhanced cardiac magnetic resonance imaging (MRI) at 3T performed 5 days and 6 months after STEMI. Infarct size was measured by assessing global myocardial extent of hyperenhancement on delayed contrast-enhanced MRI. MVO was defined as subendocardial areas of hypoenhanced signal surrounded by hyperenhanced myocardial tissue and expressed as % of total myocardium. See table. Positive TA during primary PCI was associated with infarct size reduction at 5 days and 6 months follow-up in STEMI pts with TIMI 0 flow IRA. Although this phenomenon led to positive LV remodelling, it was not associated with a reduction in MVO. Negative TA (N = 34) Positive TA (N = 17) p TIMI III flow post PCI (%) 91% (31/34) 94% (16/17) 0.86 MVO at 5 days (%) 7.1 ± 5.7 6.8 ± 4.9 0.85 Infarct size at 5 days (%) 20.6 ± 8.1 9.9 ± 7.2 <10-5 Infarct size at 6 months (%) 16.4 ± 9.9 7.2 ± 8.1 .0007 LVSVI at 6 months (ml/m 2 ) 27.5 ± 9.3 36.4 ± 12.2 0.01 LVSVI = left ventricular stroke volume index