Pressure-strain loops unveil haemodynamics behind mechanical circulatory support systems.

Abstract

Mechanical circulatory support (MCS) systems are increasingly employed in cardiogenic shock and advanced heart failure. A thorough understanding of the complex interactions occurring among heart, vasculature, and device is essential to optimize patient's management. The aim of this study is to explore non-invasive haemodynamic profiling of patients undergoing MCS based on pressure-strain (PS) analysis. Clinical and echocardiographic data from consecutive patients undergoing different MCS systems positioning/implantation admitted to the third level cardiological intensive care unit of Siena Hospital from August 2021 to November 2021 were retrospectively reviewed. Patients without a useful echocardiographic exam or without arterial blood pressure recording at the time of echocardiography were excluded. Myocardial work analysis was performed in the included patients. We reviewed 18 patients, of which nine were excluded. Included patients were three patients with intra-aortic balloon pump (IABP), two patients with durable left ventricular assist device (dLVAD), two patients with Impella®, one patient with extracorporeal membrane oxygenation (ECMO), and one patient with ECMO and IABP. Myocardial work analysis was feasible in each included patient. The use of IABP shifted the PS curve rightward and downward. Global work index (GWI) and global wasted work (GWW) decreased after IABP positioning, whereas global work efficiency (GWE) increased. The use of continuous-flow pumps, whether temporaneous (Impella®) or long term (dLVAD), induced a change in the PS loop morphology, with a shift towards a triangular shape. ECMO positioning alone resulted in a narrowing of the PS loop, with a decrease in GWI and GWE and an increase in GWW and mean arterial pressure. The combined used of IABP with ECMO widened the PS loop and improved GWI and GWE. PS loops analysis in patients undergoing MCS seems to be feasible and may unveil MCS-induced haemodynamic variations. Myocardial work could be used to monitor ventricular-arterial-device coupling and guide tailored MCS management.