Marcela Degrange

Methylene blue reduces mortality and morbidity in vasoplegic patients after cardiac surgery

BACKGROUND The discovery of nitric oxide as mediator in cardiac postoperative vasoplegia encourages the use of inhibitory drugs such as methylene blue. This drug has been used with favorable results in isolated cases. The purpose of this article is to analyze the incidence of the postoperative vasoplegic syndrome, to consider its prognosis, and to evaluate the effect of intravenous methylene blue on mortality. METHODS Cardiac surgery patients were consecutively included. Vasoplegic syndrome was defined by the presence of the following five criteria: (1) hypotension, (2) low filling pressures, (3) high or normal cardiac index, (4) low peripheral resistance, and (5) vasopressor requirements. Those with vasoplegia were randomized to receive 1.5 mg/Kg of methylene blue or a placebo. A p value less than 0.05 was considered significant. RESULTS Six hundred thirty eight cardiac surgery patients were consecutively included in this study. Fifty-six of these patients fulfilled vasoplegia criteria (8.8%) resulting in higher mortality (10.7% or 6 of 56 patients vs 3.6% or 21 of 582 patients; p value = 0.02). Those treated with methylene blue showed morbidity and mortality reductions (0% versus 21.4% or 6 of 28 patients; p value = 0.01). The duration of the vasoplegic syndrome was shorter in those patients treated with the drug, lasting less than 6 hours in all patients. Patients in the control group showed a slower recovery, lasting more than 48 hours in 8 patients (p value = 0.0007). CONCLUSIONS Vasoplegic postoperative syndrome was seen in 8.8% of all patients. Outcome in patients with vasoplegia was worse with increased morbidity and mortality. The use of methylene blue reduced the high mortality in this population.

The Calcium Sensitizer Levosimendan Gives Superior Results to Dobutamine in Postoperative Low Cardiac Output Syndrome

INTRODUCTION AND OBJECTIVES The use of levosimendan to treat postoperative low cardiac output syndrome (LCOS) has been studied in only small patient series and in randomized trials focusing on hemodynamic variables. The objective of the present study was to assess the effectiveness of levosimendan, compared with dobutamine, as a treatment for postoperative LCOS. METHODS Patients with LCOS were randomly assigned to receive either levosimendan (loading dose, 10 microg/kg, followed by 0.1 microg/kg per min for 24 h) or dobutamine (starting dose, 5 microg/kg per min). Hemodynamic and clinical parameters (including postoperative mortality and major complications), the need for the coadministration of another drug (such as an inotrope or a vasopressor) or for balloon counterpulsation, and length of stay in intensive care were all monitored. RESULTS The study included 137 patients: 69 received levosimendan, while 68 were treated with dobutamine. Although both agents improved hemodynamic parameters, the effect of levosimendan was greater and occurred earlier than that of dobutamine. In addition, levosimendan use resulted in lower postoperative mortality (8.7% vs. 25%; P< .05), a lower incidence of major postoperative complications, and less need for an additional inotropic drug (8.7% vs. 36.8%; P< .05), a vasopressor (11.6% vs. 30.9%; P< .05), or balloon counterpulsation (2.9% vs. 14.7%; P<0.05). The length of stay in intensive care was also less (66 vs. 158 h; P< .05). CONCLUSIONS In this randomized study, levosimendan proved more effective than dobutamine. Postoperative morbidity and mortality were lower, fewer patients required either an additional inotropic drug, a vasopressor or intra-aortic balloon counterpulsation, and the length of stay in intensive care was shorter.

Reversal of Electrical Storm after Intra-Aortic Balloon Pump Counterpulsation

Reversal of Electrical storm after Intra-aortic Balloon Pump Counterpulsation Balloon pump counterpulsation has been used for stabilization of refractory ventricular arrhythmia both in coronary and non-coronary patients; its usefulness for complex circulatory support is still under consideration. We report a case of electrical storm reversal after intra-aortic balloon pump counterpulsation in a patient without coronary artery disease and under biventricular support with continuous-flow devices. Our case is a 44-year-old male patient with idiopathic dilated cardiomyopathy and severe impairment ventricular function (22%) determined by echocardiography; he was admitted to the intensive care unit due to progression of dyspnea in functional class II to IV with urine output deterioration. He presented a cardiac index (CI) of 1.2 L/min/m2 and 35 mm Hg of wedge pressure. He received diuretics and dobutamine at an initial intravenous dose of 5 μg/kg/min, increasing the dose to 15 μg/kg/min due to oliguria, acidosis, and persistent low CI. The patient developed complex ventricular arrhythmia (frequent ventricular extrasystoles, couplets and triplets, and several episodes of self-limiting ventricular tachycardia), which was treated successively with magnesium, lidocaine, and amiodarone. Due to the potential dobutamine proarrhythmic effect, milrinone therapy (0.5 μg/kg/min) was started in order to reduce the dobutamine dose. The following day, under dobutamine 2.5 μg/kg/ min and milrinone 0.75 μg/kg, the patient developed sustained ventricular tachycardia and required defibrillation, orotracheal intubation and mechanical ventilation, and underwent implantation of balloon pump counterpulsation with amiodarone load and maintenance. In the next 12 hours, under balloon support, the patient remained without complex forms of ventricular arrhythmia, but due to his progression to anuria with metabolic acidosis and CI of 1.2 L/min/m2 (under milrinone 0.75 μg/kg/min), percutaneous placement of a CentriMag continuous-flow left ventricular assist device (Levitronix LLC, Waltham, Mass) and balloon removal was decided. Subsequently, and given the severe right ventricular dysfunction resistant to pharmacological therapy, a second CentriMag right ventricular assist device was placed. Two hours after the intervention, the patient developed electrical storm that was refractory to lidocaine, amiodarone loading, pacing attempts –suppression – and multiple defibrillations; he persisted with ventricular tachycardia for 24 hours (Figure 1). In such circumstances, balloon pump counterpulsation was reimplanted to stop the arrhythmia, which was resolved 2 hours after the intervention. Four days after the procedure, under balloon and the two continuous-flow device assistance (Figure 2), the patient recovered urine output, CI gradually improved to 1.9 L/min/m2, and the process of weaning from the continuous-flow devices was started, with echocardiographic monitoring to detect the gradual improvement in both ventricles. On the 6th day, the patient was extubated, and both devices were successfully removed in the following 48 hours. Balloon support was maintained for another 48 hours. During that period, the patient remained free from complex ventricular arrhythmia. Complex ventricular arrhythmia is frequently found in patients with impaired left ventricular function, which sometimes does not respond to regular therapies -such as electrolyte correction, antiarrhythmic agents, and electrical defibrillation-, posing a significant management problem. Ischemia is commonly the substrate for persistent Fig. 1. Electrical storm (A & B) under circulatory support with 2 CentriMag devices (C).

Giant Pseudoaneurysm of the Ascending Aorta

Las imagenes corresponden a un paciente de sexo masculino de 61 anos, quien fue admitido por dolor precordial; la radiografia de torax mostraba un notable ensanchamiento mediastinico (Figura 1). Presentaba el antecedente de reemplazo de la aorta ascendente y reemplazo de la valvula aortica (protesis mecanica) con reimplante coronario en 1998 (cirugia de Bentall). En 2008 fue sometido a una nueva intervencion, con reparacion de un seudoaneurisma de la aorta ascendente. La angiotomografia efectuada demostro la presencia de un seudoaneurisma gigante de la aorta ascendente de 10 cm de diametro (Figura 2).

Cartas al editorRespuesta

Hemos leído con interés el artículo de Levin et al1 en el que se presenta una comparación aleatorizada entre levosimendán (LS) y dobutamina (Db) en el síndrome de bajo gasto cardiaco postoperatorio; en él se concluye la superioridad del LS frente a Db en cuanto a morbimortalidad y estancia hospitalaria. Un aspecto clave es que, de los 68 pacientes aleatorizados a dobutamina, 45 (85,3%) se encontraban en tratamiento preoperatorio con bloqueadores beta. Tal y como expresan las Guías de Práctica Clínica de la insuficiencia cardiaca aguda2, los pacientes que reciben tratamiento con bloqueadores beta precisan mayores dosis de Db para restaurar su efecto inotrópico. Asimismo, el estudio LIDO3 —que muestra que el LS mejora los parámetros hemodinámicos en pacientes con disfunción ventricular izquierda severa respecto a la Db— concluye que el tratamiento con bloqueadores beta atenúa la acción de la Db pero no la del LS. Las diferencias estadísticamente significativas en los parámetros hemodinámicos entre LS y Db encontrados en el estudio de Levin et al pudieran deberse a la menor actividad cronotrópica e inotrópica de la Db, por encontrarse la mayoría de los pacientes en tratamiento previo con bloqueadores beta. Estas diferencias hemodinámicas en un momento tan crucial como es el bajo gasto cardiaco postoperatorio precoz (inicio de inotropo 3,5 h tras la intervención quirúrgica) pueden acabar repercutiendo en la morbimortalidad. En definitiva, podemos concluir que la acción del LS, a diferencia de la Db, no resulta atenuada por el tratamiento con bloqueadores beta. Este aspecto es importante, ya que el LS puede considerarse un tratamiento muy apropiado en casos de disfunción ventricular izquierda severa y tratamiento concomitante previo con bloqueadores beta.