Moyens mécaniques de traitement de l'insuffisance cardiaque réfractaire

Abstract

Mechanical means tend to be used more frequently nowadays for the treatment of congestive heart failure which does not respond to more normal treatment. The indications and limits of such devices, as well as their cost, must be defined. The new problem created by these therapeutic tools is the evolution of the underlying cardiac disease : should it improve the patient will be weaned from the machine, whereas if it worsens heart transplantation would be the only answer. Three types of mechanical support are described. Balloon pumping, and especially intra-aortic balloon pumping, is the technique used most often. It has a true but limited efficacy. Its best indication is cardiogenic shock by left ventricular ischaemia with normal or slightly increased peripheral resistances. Intrapulmonary balloon pumping is occasionally used, but the system can only be set up surgically. Its best indication would seem to be right-sided heart failure by pulmonary hypertension. Circulatory assistance is the second type considered. All types of bypass pumps can be used. The output used is usually less than the patient's theoretical output, the aim being to allow the myocardium to recover. Vascular access for these pumps is either femoral or intrathoracic. An oxygenator may or may not be added to the bypass circuit, and support may be mono- or biventricular. Although the non pulsatile flow has not been shown to be detrimental, this has to be investigated further. The use of these devices is limited by their effects on blood coagulation and pulmonary function. The artificial heart or artificial ventricles are the last devices described. They are either orthotopic, such as the Jarvik type, or extracorporeal, such as the Pierce artificial ventricles. Their ability to support totally the circulation for weeks allows patients to recover somewhat from acute multiple organ failure, so that they can be transplanted in better conditions. The main difficulty in using such devices is patient selection, with the exclusion straight-off of those patients with chronic multiple organ failure who will in any case not be suitable for transplantation later on. Because there are numerous mechanical means now available for the treatment of congestive heart failure no longer responsive to drugs, the choice of device to be used depends on the ultimate goal aimed for, i.g. transplantation or not.