Cardiogenic shock (CS) is a state of tissue hypoperfusion with or without concomitant hypotension, in which the heart is unable to deliver sufficient blood and oxygen to meet the body's demands, resulting in organ failure. It is classified into stages A to E by the Society of Cardiovascular Angiography and Interventions (SCAI): stage A - patients at risk for CS; stage B - patients at beginning stage of CS with hypotension or tachycardia without hypoperfusion; stage C - classic CS with cold and wet phenotype requiring inotropes/vasopressors or mechanical support to maintain perfusion; stage D - deteriorating on current medical or mechanical support requiring escalation to more advanced devices; and stage E - includes patients with circulatory collapse and refractory arrhythmias who are actively experiencing cardiac arrest with ongoing cardiopulmonary resuscitation1. The most common causes of CS are acute MI (AMI) representing 81% of cases in a recently reported analysis2, and acute decompensated heart failure (ADHF). CS is classically characterized by congestion and impaired perfusion, manifested by elevated filling pressures (pulmonary capillary wedge pressure [PCWP], left ventricular end-diastolic pressure [LVEDP], central venous pressure [CVP], and right ventricular end-diastolic pressure [RVEDP]), decreased cardiac output (CO), cardiac index (CI), cardiac power output (CPO), and end-organ malfunction3. In the past, the only available treatments for AMI complicated by CS were early revascularization and medical management with inotropes and/or vasopressors4. More recently, with the advent of mechanical circulatory support (MCS) devices and the recognition that escalation of vasopressors is associated with increased mortality, there has been a paradigm shift in the treatment of both AMI and ADHF related CS5,6.
In the current era of percutaneous ventricular assist devices (pVAD), there are a number of MCS device platforms/configurations available, which provide univentricular or biventricular circulatory and ventricular support with and without oxygenation capability7. Despite steady increases in the use of pVADs to treat both AMI and ADHF CS, mortality rates have remained largely unchanged5. With emerging evidence for possible clinical benefits to early unloading of the left ventricle (LV) in AMI8 and early use of MCS in AMI CS9, the use of MCS continues to increase.
The Left Atrial to Femoral Artery Bypass (LAFAB) MCS device bypasses the LV by draining blood from the left atrium (LA) and returning it to the systemic arterial circulation via the femoral artery (Figure 1). It is supported by an external centrifugal pump that offers 2.5-5.0 liters per minute (L/m) flow (new generation pump, designated as LifeSPARC, capable of up to 8 L/m flow) depending on the size of the cannulas. Once the blood is extracted from the LA via the transseptal venous cannula, it passes through the external centrifugal pump which recirculates the blood back into the patient's body via the arterial cannula placed in the femoral artery.

Figure 1: LAFAB setup. Image courtesy of TandemLife, a wholly owned subsidiary of LivaNova US Inc. Please click here to view a larger version of this figure.