Reduced Flow Rate, Acute Hemolysis, and Restricted Anterior Mitral Leaflet Opening During Mechanical Circulatory Support for End-stage Nonischemic Cardiomyopathy

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.

Hemolysis during short-term mechanical circulatory support: from pathophysiology to diagnosis and treatment

INTRODUCTION

Despite advances in heart failure therapies and percutaneous coronary interventions, survival for cardiogenic shock remains poor. Percutaneous ventricular assist devices (pVAD) are increasingly used, but current evidence remains conflicting. The Impella is an example of such a device, based on a catheter mounted micro-axial continuous flow pump, that has been rapidly adopted in routine practice. An important aspect in the post implantation care is the prevention of complications. Hemolysis is one of the more frequent complications seen with this device.

AREAS COVERED

In this review we discuss the pathophysiology, diagnosis and treatment of hemolysis in patients supported with a pVAD. A practical algorithm for rapid identification of hemolysis and the underlying cause is presented, allowing for early treatment and prevention of further complications.

EXPERT OPINION

Hemolysis remains a threat to patients supported with any mechanical circulatory support device. Prevention as well as treatment demands for sufficient knowledge about the device, the optimal position and hemodynamics. Future studies should try to clarify some of the elements that are still unclear such as optimal anticoagulation, the place of pentoxyfilline or extracorporeal removal of free hemoglobin. This could help to optimize outcomes in clinical practice as well as future studies.