Recognizing Patients as Candidates for Mechanical Circulatory Support Along the Spectrum of Cardiogenic Shock

Key Topics and Take Aways:

• Appropriate diagnosis, screening, selection, and treatment is crucial to achieving good outcomes with MCS in patients with cardiogenic shock.
• SCAI classification of patients with cardiogenic shock and cardiac arrest (CA) might support emergency selection of percutaneous ventricular assist devices (pVADs) since increasing SCAI shock stage after CA is associated with increased requirement for renal replacement therapy, 30-day mortality, mortality attributed to multiorgan dysfunction, and death due to cardiac etiology.
• To predict mortality, it is important to evaluate shock patients at both baseline and 24 hours after shock onset and initiation of treatment; any chosen therapy should be able to quickly restore hemodynamic status across all SCAI stages. 
• Registry data suggest improved survival when LV support is initiated early, thus, the authors recommend active surveillance for CS to facilitate early identification and selection of optimal treatment. 
• The authors conclude, “The correct identification of candidates for MCS, with a timely screening, adequate clinical surveillance, and a patient-tailored evaluation of the relative contraindications, might all contribute to breaking the bad outcome barrier.” 

In this paper, the authors discusses the latest guidance for identifying patients with cardiogenic shock (CS) who are candidates for mechanical circulatory support (MCS) based on the etiology of shock and the timing of MCS insertion. The authors write, “appropriate diagnosis, screening, selection, and treatment are crucial to achieving good outcomes with MCS.” In this article they provide an overview of patient screening, emphasizing the importance of correctly identifying patients, recognizing clinical predictors of their trajectories, and attending to complications associated with the use of percutaneous ventricular assist devices (pVADs).

The authors identify three phenotypes of cardiogenic shock, which while derived from patients with acute myocardial infarction cardiogenic shock (AMICS), they believe are also applicable to patients with heart failure CS (HF-CS). These phenotypes are: noncongested CS, cardiorenal CS, and cardiometabolic CS. 

The authors discuss how cardiac arrest (CA) substantially contributes to the risk of in-hospital mortality in CS. They write, “SCAI classification of patients with CS and CA might support emergency selection of invasive therapies such as pVAD, as increasing SCAI shock grade after CA is associated with increased requirement for renal replacement therapy, 30-day mortality, and mortality attributed to multiorgan dysfunction and death due to cardiac aetiology.”

"Early AMI-CS detection and development of an immediate response algorithm, including prompt MCS, is vital, as registry data indicates improved survival with early LV support."

With regard to SCAI classification, the authors explain that it is important to evaluate shock patients at both baseline and 24 hours after shock onset and initiation of treatment to predict mortality. In addition, they emphasize, “any chosen therapy should be able to quickly restore hemodynamic status across all SCAI states. Indeed, this is unquestionably true for SCAI E patients who would have no chance of survival if still classified as stage E at 24 hours.”

With registry data suggesting improved survival when LV support is initiated early, the authors recommend active surveillance for CS to facilitate early identification and selection of optimal treatment. They discuss early predictors of outcomes in CS (eg, arterial lactates, pH, echocardiographic data, and systolic blood pressure in addition to SCAI staging) and highlight the importance of sex equality in the use of microaxial flow pumps.

The authors conclude, “The correct identification of candidates for MCS, with a timely screening, adequate clinical surveillance, and a patient-tailored evaluation of the relative contraindications, might all contribute to breaking the bad outcome barrier.”