Left Ventricular Support by Catheter-Mounted Axial Flow Pump Reduces Infarct Size

The transvalvular assist device Impella (Aachen, Germany) is a potent, miniaturized pump that offers the possibility of unloading the left ventricle (LV) via the femoral placement (1). In vivo and clinical use of this device has indicated that the pump produces a mean flow of 4.2 l/min at maximal rotational speed (2). Mechanical unloading of the myocardium during ischemiaandreperfusionhasbeenshowntoreduceLVpressure work and myocardial oxygen consumption (3–5). However, the installation of a left heart bypass during myocardial infarction (MI) is a cumbersome clinical procedure, with important comorbidity. Pharmacologic approaches, such as the early use of beta-blockers,nitroglycerin,andangiotensin-convertingenzyme inhibitors, have achieved infarct size reduction in experimental models (6–10). The use of beta-blockers and angiotensin-converting enzyme inhibitors has rapidly advanced from experimental studies to the clinical recommendation as standard therapy in most patients experiencing an MI. However, clinical trials on the early use (first day of infarction) showed an increased incidence of hypotension (9–12). Mechanical support combines the beneficial effects of myocardial unloading and an increase in perfusion pressure. It can therefore be used early, even during ischemia and in myocardial failure. This new pump allows unloading of the LV via a peripheral approach in the setting of acute MI. We wanted to investigate the effect of this microaxial blood pump on MI size.