Left ventricular support by Catheter-Mountedaxial flow pump reduces infarct size
Bart Meyns, MD, PhD*,*,
Jarek Stolinski, MD*,
Veerle Leunens*,
Erik Verbeken, MD, PhD* and
Willem Flameng, MD, PhD*
* Center for Experimental Surgery and Anesthesiology, Cardiovascular Research Unit, Catholic University of Leuven (KUL), Leuven, Belgium
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Figure 1 The microaxial blood pump has an outer diameter of 6.4 mm and is driven by a miniaturized electrical motor incorporated in the housing. The cannula (upper panel) is placed across the aortic valve, and the pump aspirates the blood from the left ventricular cavity to expel it in the ascending aorta. A differential pressure sensor (lower panel) continuously measures the pressure difference between the inflow and outflow of the pump and allows the calculation of the produced pump flow.
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Figure 2 Myocardial metabolism during ischemia and reperfusion for the four different groups: control group (squares), fully supported group (circles), group supported during reperfusion only (diamonds), and group with partial support during reperfusion (x). *Significant difference (analysis of variance with Newman-Keuls post-hoc testing: p < 0.05) compared with the control group. Mechanical support influences myocardial oxygen consumption (MVO2) (upper panel). There was a significant reduction of oxygen consumption in all supported groups at all supported times. The lactate extraction ratio (LER) (lower panel) was significantly reduced during ischemia in all groups, except for the fully supported group. At reperfusion, the LER increased again, but the differences are not significant.
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Figure 3 Myocardial blood flow in the subendocardial (upper panel) and subepicardial (lower panel) regions of the occluded area for the different groups (control group represented by open bars; fully supported group = darker shaded bars; group supported in reperfusion only = lighter shaded bars; and group with partial support during reperfusion = solid bars). During occlusion, there was almost no flow in either of the groups. At reperfusion, the fully supported group was the only group to show normal myocardial perfusion. BS = baseline; occl = during coronary occlusion; reperf = reperfusion. *Significant difference (Student t test) compared with the baseline value. #Significant difference (Student t test) compared with the control group.
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Figure 4 Myocardial infarct sizes of the four different groups: 1 = control group; 2 = full support during ischemia and reperfusion; 3 = full support during reperfusion only; 4 = partial support during reperfusion only. The open bars indicate the area at risk; solid bars indicate infarct size. The intervals indicate the standard deviation of the mean value. *Significant difference (Student t test) compared with the control group.
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Figure 5 Correlations between myocardial oxygen consumption (MVO2) during ischemia (upper panel) and during reperfusion (lower panel) and the final infarct size of each animal. Infarct size correlated better with MVO2 during reperfusion. The intervals indicate the 95% confidence intervals. Solid lines and circles represent the regression with 95% confidence limits.
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