Mechanical Circulatory Support (MCS)

Heart transplant (HT) remains the gold standard treatment for advanced heart failure (HF). However, indications for mechanical circulatory support (MCS) are broadening due to satisfactory results achieved with novel continuous-flow devices. In general, MCS is intended for patients with acute or chronic HF who cannot be stabilized with pharmacologic treatment.

MCS can be used as short-term or long-term therapy in patients with advanced HF. Short-term MCS devices (ie, intra-aortic balloon pump [IABP], percutaneous ventricular assist devices [VADs], and extracorporeal membrane oxygenation [ECMO]) are used to reverse critical end-organ hypoperfusion and hypoxia in the setting of cardiogenic shock or, in the case of ECMO, critical respiratory failure. Long-term MCS (ie, durable VAD and total artificial hearts [TAHs]) can be used in selected patients when medical therapy is insufficient or short-term MCS has not led to sufficient improvement or recovery.

IndicationsTop

Based on the 2021 European Society of Cardiology (ESC) guidelines for the diagnosis and treatment of acute and chronic HF, MCS can be used to achieve several clinical goals:

1) Bridge to decision (BTD)/bridge to bridge (BTB): Short-term MCS (ECMO, IABP, or Impella), to stabilize the patient during cardiogenic shock and allow for further evaluation for long-term MCS or HT candidacy.

2) Bridge to candidacy (BTC): MCS (usually left ventricular assist device [LVAD]), to improve end-organ perfusion in order to resolve reversible contraindications to HT.

3) Bridge to transplant (BTT): MCS (LVAD, biventricular assist device [BiVAD], or TAH), until HT in patients at high risk of death while waiting on the transplant list.

4) Bridge to recovery (BTR): MCS (short-term or long-term) in patients with a potentially reversible deterioration in cardiac function until recovery.

5) Destination therapy (DT): Long-term MCS (LVAD) as an alternative therapy in patients with end-stage HF ineligible for HT.

The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profiles were developed to classify patients with a potential indication for durable MCS device implantation based on clinical parameters and characteristics:

1) INTERMACS 1: Critical cardiogenic shock.

2) INTERMACS 2: Progressive decline despite IV inotropic support.

3) INTERMACS 3: Stable on inotropes or inotrope dependent.

4) INTERMACS 4: Frequent flyer.

5) INTERMACS 5: Housebound.

6) INTERMACS 6: Exertion limited.

7) INTERMACS 7: Advanced New York Heart Association (NYHA) class III symptoms.

Based on the INTERMACS profile, prognostic stratification can be made, and treatment can be recommended as presented in the algorithm in the 2021 ESC guidelines for the diagnosis and treatment of acute and chronic HF. In general, patients with INTERMACS profiles 1 to 4 should be considered for MCS although timing and duration of MCS will depend on the clinical scenario. Patients with INTERMACS profiles 5 and 6 may also be considered for long-term MCS in the presence of high-risk characteristics. It is also recommended to list patients with INTERMACS profiles 3 to 4 without contraindications to HT or with contraindications resolved during BTC MCS for HT.