Mechanical Circulatory Support in Left Ventricular Heart Failure

Abstract: Short-term mechanical circulatory support (MCS) with ventricular assist devices or veno-arterial extracorporeal membrane oxygenation (VA ECMO) has become the standard treatment in patients with cardiogenic shock unresponsive to pharmacological treatment. However, the haemodynamic effects of these devices are not yet fully described, nor are their effects on ventricular function and myocardial recovery.The aims of this thesis are to increase knowledge of the haemodynamic changes during MCS in different settings and to provide new insights into how MCS therapy should be guided in the specific patient.In Studies I and II, we developed experimental animal models to investigate the effect of VA ECMO on left ventricular (LV) performance and size of myocardial infarction in different cannulation strategies. In Study I, we found that the LV performance was negatively affected by VA ECMO in both centrally and peripherally cannulated animals. In Study II, we specifically studied the effect of VA ECMO with and without the addition of LV drainage on the size of experimentally induced myocardial infarction. The results showed that active LV decompression had no effect on infarct size in the acute setting.Studies III and IV are retrospective studies on patients in cardiogenic shock treated with short-term mechanical support with either Impella® (Studies III and IV) or VA ECMO (Study IV). In Study IV, we concluded that treatment with Impella® has excellent effects on haemodynamic parameters and an acceptable mortality and complication rate. The studied pre-implantation patient parameters did not significantly affect outcome. In Study IV, we compared the outcome of patients treated with Impella® with those treated with VA ECMO. After adjustment for pre-implantation patient status, as defined by SAVE score, no difference in short- or long-term mortality was seen between the two groups.In conclusion, VA ECMO, whether central or peripheral, negatively affects the LV, and the addition of a LV drain has no effect on infarct size in these experimental models. Both Impella® and VA ECMO offer good haemodynamic results with acceptable mortality and complication rates in patients with refractory cardiogenic shock. When adjusted for the SAVE score, the outcomes of both treatment modalities are comparable.