Myocardial recovery by mechanical unloading with left ventricular assist system.

It has been generally believed that advanced congestive heart failure (HF) is progressive, but there is increasing evidence that mechanical unloading with the use of left ventricular assist system (LVAS) occasionally reverses the progress of HF and permits device explantation. This "bridge to recovery" strategy is attracting interest, not only for the treatment of severe HF, but also in the study of the pathophysiological mechanisms involved in remodeling and its regression, with the hope of establishing reliable indicators of sustained recovery and strategies to enhance this process. Tissue samples obtained at the time of LVAS implantation and at explantation enabled study of the effects of LV unloading at the cellular and gene levels. However, the problem with these analyses is the lack of correlation between clinical improvement and cellular or molecular changes. Clinically, there are still many questions about the application of this strategy. The evaluation of LV function while on LVAS and the prediction of sustained recovery after explantation of the device have been the major concerns. Pharmacological regimens to promote recovery have been proposed, but require validation by multicenter study. Further investigation of the underlying mechanisms may help to establish strategies to enhance the recovery process.