Haemodynamic simulation and the effect of early left ventricular unloading in pre-shock acute coronary syndrome

Understanding the pathophysiological background on haemodynamic changes in acute myocardial infarction and during its interventional treatment is important to adequately use mechanical circulatory support.

We describe haemodynamic simulations based on a real case scenario of infarct-related ischaemia with beginning haemodynamic compromise illustrating the advantage of active haemodynamic support. The patient case used for computer simulation is that of an acute coronary syndrome, slightly hypotonic. The right coronary artery is chronically occluded, and both left main and a saphenous vein graft to the left anterior descending coronary artery (LAD) show subtotal stenosis. In this scenario used for computer modelling of haemodynamics, we illustrate how unprotected percutaneous coronary intervention would limit coronary blood flow and constantly reduce myocardial contractility until cardiac arrest occurs. The simulation demonstrates how an intra-aortic balloon pump would delay but not prevent that compromise and how an Impella microaxial pump will actively support cardiac output and stabilize haemodynamics even when prolonged balloon inflations are performed, which will temporarily stop coronary perfusion.

The simulation illustrates how temporary circulatory support with an Impella microaxial pump can stabilize haemodynamics and allow for a safe procedure in an unstable patient. Using computer simulation of haemodynamics to understand changes in haemodynamics when performing interventions in unstable patients might help to properly select a suitable support device if needed.