Therapeutic strategies for cardiogenic shock, 2006

Cardiogenic shock

Cardiogenic shock is the most common cause of death in patients hospitalized with acute myocardial infarction and is associated with a poor prognosis. More than 75% of cases are due to extensive left ventricular infarction and ventricular failure. Other causes include right ventricular infarction and papillary muscle rupture with acute severe mitral regurgitation. Activation of neurohormonal systems and the systemic inflammatory response worsens shock. To improve outcomes, cardiogenic shock needs to be recognized early in its course and its cause needs to be diagnosed rapidly. Treatment strategies using intra-aortic balloon counterpulsation and emergency revascularization by percutaneous coronary interventions or coronary bypass surgery have been shown to improve outcomes. To decrease the incidence of cardiogenic shock, public education regarding early presentation to hospital in the course of acute chest pain is important. Emergency medical transport systems may need to take patients with complicated acute myocardial infarction to hospitals with the capability to perform urgent revascularization.

Anthrax toxin-induced shock in rats is associated with pulmonary edema and hemorrhage

Bacillus anthracis infections are frequently associated with severe and often irreversible hypotensive shock despite appropriate antibiotics and aggressive hemodynamic and pulmonary support. Based on the observations that the anthrax secreted proteins-protective antigen (PA), lethal factor (LF), and edema factor (EF) also produce shock and mortality in animal models, we chose to characterize further the clinical chemistries and microscopic pathology of toxin treated rats. Groups of three male Sprague Dawley rats received bolus intravenous infusions of PA/LF, PA/EF, LF, or EF alone and blood samples and tissues were collected and assayed for chemistries and tissue pathology. In PA/LF and PA/EF treated animals but not other groups, chemistries showed transaminasemia and elevated lactate dehydrogenase. PA/LF treated animals alone showed elevated hemoglobin and hematocrits; PA/EF treated animals alone showed lymphopenia. Pathology was remarkable for pulmonary edema in PA/LF treated rat lungs and pulmonary hemorrhage in PA/EF treated rat lungs. These results are consistent with our and others' previous findings that the morbidity and mortality associated with anthrax are not cytokine-mediated but due to a direct effect of the toxins on the cardiovascular system along with toxin-specific alterations in blood counts. PA/LF pathology matches that seen with acute cardiac failure, and PA/EF pathology coincides with direct vascular endothelial injury. These observations provide a rational basis for drug interventions to reduce the effect of these toxins on the heart and blood vessels.