Short-term percutaneous mechanical circulatory support: no promise without positioning!

Short-term percutaneous mechanical circulatory support by a micro-axial flow pump is increasingly used to support the left ventricle in cardiogenic shock. After a correct indication and placement, appropriate device management in the cardiac intensive care unit is vital to ensure optimal pump function and adequate haemodynamic support. A key element hereby is a correct percutaneous ventricular assist device (pVAD) position. This review explains how an optimal left-sided pVAD position can be achieved and maintained, focusing on the correct insertion depth and rotational angle. Useful imaging techniques, placement and replacement manoeuvres, and monitoring options through the console are discussed. The frequently encountered problem of mal-rotation towards the mitral valve, which may cause suction alarms, haemolysis, aortic regurgitation, and inadequate haemodynamic support, is explained. Finally, a practical bedside approach to assess pVAD position and discern suction alarms due to mal-positioning from haemodynamic problems is proposed. Graphical Abstract Integrative approach to percutaneous ventricular assist device (pVAD) position monitoring in the cardiac intensive care unit. First, one must evaluate whether the motor current (green waveform) is pulsatile. Very poor native heart contractility may cause a non-pulsatile motor current. Otherwise, a lack of pulsatility indicates that the inlet and outlet of the micro-axial flow pump are within the same heart chamber. In case of an overly deep insertion, both the placement signal (red waveform) and the left ventricular pressure waveform (white waveform) show a ventricular signal. When the pVAD is dislocated towards the ascending aorta, both the placement signal and the left ventricular pressure waveform demonstrate an arterial waveform. If the motor current is pulsatile, the shape of the left ventricular pressure waveform and its relationship with the aortic waveform on the placement signal are evaluated. When the systolic part of the ventricular waveform is at or above the level of the placement signal, but a decrease in the left ventricular diastolic pressure is observed, the problem is ventricular preload. When preload decreases further, this may lead to diastolic suction alarms when the pressure drops below -40 mmHg. If, on the other hand, the ventricular systolic pressure is incongruent and beneath the level of the placement signal, it indicates a problematic positioning. Echocardiography is needed to evaluate the exact type of abnormality. When motor speed is increased in such cases, a continuous suction alarm is created. LV, left ventricle; pVAD, percutaneous ventricular assist device.