Effects of mechanical left ventricular unloading by impella on left ventricular dynamics in high‐risk and primary percutaneous coronary intervention patients

Objectives : We studied online left ventricular (LV) dynamic effects of mechanical LV unloading directly after percutaneous coronary intervention (PCI). Background : Limited clinical information is available on the direct LV dynamic consequences of LV unloading in patients undergoing high‐risk PCI and primary PCI for acute ST‐elevation myocardial infarction. Methods : The effects of the Impella LP2.5 device on LV dynamics were studied in 11 patients (elective high‐risk PCI, n = 6; primary PCI, n = 5). LV pressure and volume were continuously assessed by a pressure‐conductance catheter at 4 different support levels of the Impella, from 0 L/min at baseline to 2.5 L/min at maximal support. Results : The response to increased LV unloading was not different between both groups of patients. The pooled data showed no change on global and systolic LV function during increased LV unloading, while diastolic function showed improvement as indicated by an increased LV compliance in all patients. There was a decrease in end‐diastolic pressure from 22 ± 12 to 13 ± 9 mm Hg (P = 0.0001), in end‐diastolic elastance from 0.134 ± 0.060 to 0.091 ± 0.064 mm Hg/mL (P = 0.009), and in end‐diastolic wall stress from 84 ± 50 to 47 ± 39 mm Hg (P = 0.004). Conclusions : LV unloading decreases end‐diastolic wall stress and improves diastolic compliance dose‐dependently. Our results indicate beneficial LV unloading effects of Impella during high‐risk and primary PCI. © 2009 Wiley‐Liss, Inc.