Microvascular Obstruction by Intracoronary Delivery of Mesenchymal Stem Cells and Quantification of Resulting Myocardial Infarction by Cardiac Magnetic Resonance

Intracoronary injection of mesenchymal stem cells (MSCs) has been proposed as a potential therapeutic option in repair of the ischemic- or infarct-damaged heart. However, because MSCs are large (rounded up cells are ≈22 to 25 μm diameter), an important consideration of this approach is the potential of these cells to induce myocardial damage by microvascular obstruction as has been reported previously.1 We present cardiac magnetic resonance (CMR) images, with corresponding biochemical and histological data from 2 healthy sheep in which 25 or 75×106 MSCs were injected through an over-the-wire balloon catheter into the mid left anterior descending coronary artery with the balloon inflated briefly before and during the infusion of the cell suspension. The MSC had been prepared as described previously and filtered with a 20-μm filter.2 Serial troponin levels were measured for 24 hours and, weight-adjusted gadolinium (Multihance; 0.1 mmol/kg) was injected 45 minutes before …