The latter have the advantage of availability, simplicity of use, and installation. The present review will concentrate on the two pVADs that have received FDA and CE approval for clinical use, the TandemHeart (Cardiac Assist Inc., Pittsburgh, PA, USA) [3] and the Impella Recover LP 2.5 (AbioMed, Europe, Aachen, Germany) [4] (Figure 1). It also etc includes a section on the use of extracorporeal life support in cardiogenic shock. Figure 1 Schematic representation of two commercially available percutaneous ventricular assist devices (VAD). (a) The TandemHeart pVAD consists of a 21F left atrial inflow cannula, an extracorporeal centrifugal pump rotating at up to 7500rpm, … 2. Device Specificities, Implantation, and Complications The TandemHeart creates a percutaneous left atrial-to-aortal shunt.
Within no more than half an hour, blood is collected from the left atrium, directed to an extracorporeal pump, and then redirected to the abdominal aorta. An operator well trained in transseptal puncture should perform TandemHeart implantation. After gaining femoral venous access, transseptal puncture is performed using standard Brockenbrough technique. When undertaken under cardiopulmonary resuscitation, external cardiac massage should be briefly stopped during a few seconds in order to allow the operator to perform atrial septum puncture. Then, the interatrial septum is dilated using a two-stage (14�C21 French) dilator to accommodate the 21-French (Fr) left atrial drainage cannula. Using the Seldinger technique, a 15�C17-Fr femoral artery cannula is placed retrogradely in the iliac artery.
Both cannulae are connected to the centrifugal pump under careful evacuation of any air within the tubing. The centrifuge is powered by a microprocessor-controlled electromechanical unit, which enables rotation at 3,500 to 7,500 rotations per minute (rpm). The 15-Fr cannula allows a maximal estimated flow of 3.5L/min and the 17-Fr 4 to 5L/min depending on systemic vascular resistance. The pump’s efficacy also depends on the proper suction of blood from the left atrium, which could be impaired by wedging of the cannula against the atrial wall in case of deep position of the cannula or inappropriate filling of the left atrium. Special care must be taken to avoid displacement or kinking of the inflow cannula, particularly the dislodgement of the cannula from the left into the right atrium.
The latter will result in loss of oxygenation and functionally corresponds to a right-to-left shunt. Therefore, the inflow cannula needs AV-951 to be secured and immobilized in order to minimize the risk of dislodgement. Duration of support classically extends from hours to 15 days. When appropriate, a stepwise weaning process (for instance by 500mL/minute every hour) should be initiated. Weaning criteria are usually met when cardiac index and mean arterial pressure exceed 2.