Inhaltszusammenfassung

The prevalence of postoperative myocardial dysfunction following cardiac surgery is a relatively common phenomenon even in patients with a normal preoperative ventricular function and its grade depends on factors such as patient age, the kind of procedure performed and the existing co-morbidities. The phenomenon becomes much more intense and more difficult to treat in patients with pre-existing heart failure. This condition results in delayed recovery, organ failure, prolonged stay in the ICU...The prevalence of postoperative myocardial dysfunction following cardiac surgery is a relatively common phenomenon even in patients with a normal preoperative ventricular function and its grade depends on factors such as patient age, the kind of procedure performed and the existing co-morbidities. The phenomenon becomes much more intense and more difficult to treat in patients with pre-existing heart failure. This condition results in delayed recovery, organ failure, prolonged stay in the ICU and in the hospital, increased morbidity and mortality and significantly increased costs. When myocardial dysfunction is clinically significant it may jeopardize tissue perfusion. In this case the use of inotropic agents is necessary in order to support circulation until endogenous myocardial function is restored. The classic treatment strategies have traditionally focused on the use of catecholamines and, in particular, β-adrenergic agents, which are also characterized as first choice drugs due to their beneficial effects on myocardial contractility and cardiac output. However, the use of these sympathomimetic drugs can be accompanied by many side effects such as tachycardia, arrhythmias, adverse effects on ventricular load conditions and ultimately myocardial oxygen supply-consumption disorders. In addition, down-regulation of β-adrenergic receptors in patients with chronic heart failure may alleviate the response to exogenously administered catecholamines. Levosimendan is a new inotropic drug, belonging to the class of calcium sensitizers. It increases myofilament calcium sensitivity during cardiac systole by binding to troponin C in a calcium-dependent manner. This interaction stabilizes the calcium-induced conformational change of tropomyocin, thereby augmenting actin-myocin cross-bridging without raising intracellular calcium concentrations. It also binds to and opens ATP-dependent potassium (KATP) channels, having a direct effect on vascular smooth muscle cells, causing vasodilation. The beneficial effects of levosimendan despite the existing controversy have already been described in many studies of the literature concerning internal medicine and surgical patients. The aim of this study is to evaluate whether benefits of levosimendan could be extended to improve the outcome of patients with low preoperative EF and myocardial dysfunction following cardiac surgery. The results of this work show substantial positive effects of levosimendan on the short- and long-term outcome in patients with severely reduced ejection fraction undergoing cardiac surgery. The prophylactic administration of levosimendan significantly improved the short- and long-term outcomes of the treated patients. The results of this study can be summarized in the following conclusions: • Levosimendan improves short- and long term survival after cardiac surgery. • It significantly facilitates postoperative improvement of the EF. • It provides a better hemodynamic stability and reduces the need for inotropic support of the patients. • It does not affect the need for mechanical hemodynamic support with the IABP. • It reduces mechanical ventilation time and facilitates a faster weaning from ventilator. • It does not reduce the stay in the ICU and the total hospital stay. • It reduces rehospitalization and readmissions to the hospital due to cardiac aetiology. • These patients reported a better clinical symptomatology with less angina and dyspnea. • It reduces the need for transfusion of blood products. • It reduces the occurrence of postoperative arrhythmias. • It provides a renal protective effect and reduces the need for renal replacement therapy. • It reduces the systemic inflammatory response and provides a faster recovery from it. • It limits the amount and extense of the inevitable myocardial injury after cardiac surgery. • It ameliorates organ and tissue perfusion and metabolic balance postoperatively. It is also important to mention that the purpose of this study was to demonstrate a possible positive effect of levosimendan as an additive treatment and not as a monotherapy, as the conventional medical, surgical and mechanical therapeutical means remain the cornerstone of the treatment of a cardiac surgery patient. The mentioned limitations of a retrospective analysis with unequal basic characteristics were attempted to compensate with the help of a multivariate regression analysis. In order to allow a more precise quantification of the positive or potential negative effects of levosimendan, more prospective randomized studies would be necessary, in which the documentation and control of the other perioperative therapy are standardized and comprehensibly documented.» weiterlesen» einklappen

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DDC Sachgruppe:
Medizin