Abstract 10915: Microvascular Obstruction Identifies a Subgroup of Patients Who Benefit From Intracoronary Stem Cell Delivery Following ST-Elevation Myocardial Infarction

Abstract

Aims: Microvascular obstruction (MVO) following ST-elevation myocardial infarction (STEMI) is associated with greater infarct size, adverse left-ventricular (LV) remodeling and reduced ejection fraction. We hypothesized that patients with MVO may constitute a subgroup of patients that would benefit from intracoronary stem cell delivery with bone marrow mononuclear cells (BMCs) given previous findings that BMCs tended to improve LV function only in patients with significant LV dysfunction. Methods and Results: We analyzed the cardiac MRIs of 356 patients (303 M, 53 F) with anterior STEMIs who received autologous BMCs as part of 3 clinical trials that included the Cardiovascular Cell Therapy Research Network (CCTRN) TIME trial and its pilot (n=157), the multi-center French BONAMI trial (n=91) and the SWISS-AMI trial (n=108). All patients received 100 - 150 million intracoronary autologous BMCs or placebo / control 3 - 7 days following primary PCI and stenting. LV function, volumes, infarct size and MVO were assessed prior to infusion of BMCs and 1 year later. Patients with MVO (n=210) had reduced LVEF and much greater infarct size and LV volumes compared to patients without MVO (n=146) (all p < 0.01) (TABLE). At 12 months, patients with MVO who received BMCs had significantly greater recovery of LVEF compared to those patients with MVO who received placebo (absolute difference = 2.7 %; p < 0.05). Similarly, the changes in left-ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV) were consistent with significantly less adverse remodeling in patients with MVO who received BMCs compared to placebo ( % change; LVEDV = -9.7%; p < 0.05 and LVESVI = -14.7 %; p = 0.006). In contrast, patients without MVO experienced no benefit of BMC administration compared to placebo. Conclusion: The presence of MVO on cardiac MRI following STEMI identifies a subgroup of patients who may benefit from intracoronary stem cell delivery of BMCs.