7.2 Circulatory Support for Cardiogenic Shock: Matching the Device Strategy to the Patient for Best Outcomes

These proceedings summarize the educational activity of the 17th Biennial Meeting of the International Andreas Gruentzig Society held January 30 to February 2, 2024 in Chiang Rai, Thailand.

Faculty Disclosures     Vendor Acknowledgments

2024 IAGS Summary Document

Statement of the problem or issue

Cardiogenic shock (CS) is increasing; the incidence has doubled for patients with acute myocardial infarction (AMI) and those with heart failure (HF). Mortality has not changed despite advances in technology; only ≈50% of patients with CS survive to discharge. CS as a complication of MI or HF is heterogenous, and outcomes depend on clinical phenotype and severity. Clinical (hemodynamic) phenotype is specified as predominantly left sided (LV HF-CS), right sided (RV HF-CS), or both (Bi-V HF-CS). Severity is based on the SCAI-Cardiogenic Shock Working Group (SCAI-CSWG) classification, which has 5 stages: A, B, C, D, E. Other specifications include acuity versus chronicity, and whether the cause is reversible or not. Management requires a right heart cath (RHC) with hemodynamic assessment and phenotyping; any mortality benefit depends on this evaluation. Temporary mechanical circulatory support (tMCS) can be employed for CS; excellent reviews of the topic have been published.¹ Several devices are available (Table 1).

Table 1. Devices for temporary hemodynamic support (tMCS).

IABP = intra-aortic balloon pump; LVAD = left ventricular assist device; RVAD = right ventricular assist device; VA-ECMO = veno-arterial extracorporeal membrane oxygenation.

Most algorithms for MCS selection for AMI with CS, and the one we use at my institution, start with Impella CP and then escalate to ECMO as required. And typically, with ECMO, we vent the LV either with Impella (abbreviated EcPella), IABP, or with trans-septal placement of an LA cannula drain (abbreviated LAVA). For patients with HF-CS that is early stage, we start with an Impella CP. But, for patients with Stage C or greater, ECMO with LV venting provides the needed support. Isolated RV shock requires Impella RP; for biventricular support we use ECMO and an LV vent. It is critical to recognize that benefit from mechanical therapies for shock comes not just from improving perfusion with augmentation of cardiac index, but also the hemodynamic support allows more aggressive venous decongestion through diuresis. Venous congestion leads to renal and hepatic failure and a metabolic spiral downward. Rapid and early support can prevent or reverse metabolic derangements that lead to irreversible decline. Importantly, though, mechanical devices are associated with complications including major bleeding and hemolysis and should only be continued as long as necessary. The strategy is to decongest the venous circulation as rapidly as feasible, while simultaneously reversing any reversible causes of shock or supporting the patient through the transient decompensation.

Gaps in current knowledge

Until the recent publication of the DanGer Shock trial showed survival benefit with use of Impella in AMI shock, there was no proven mortality benefit with any device therapy.2    Nevertheless, additional studies are needed to examine benefits of combination therapy, including ECMO with LV venting in severe shock, strategies for non-AMI severe shock, and RV and BiV shock. A consideration of major importance is a de-escalation plan to wean off MCS. Differences in outcomes may reflect how de-escalation was carried out. The goal is to use support only as long as necessary. Continuous re-assessment is required. When congestion has cleared, the RV and end organs have recovered, and cardiac index (CI) on stable pressor doses is maintained, then weaning from MCS can be tested: If successful – decannulate. For patients stabilized using femoral MCS that can’t quickly be weaned, a transition to axillary support may permit extubation and ambulation.

Possible solutions and future directions

There are many unanswered questions that help determine future directions in this field. Some of these are listed in Table 2.

Table 2. Current unanswered questions and future directions.

Future innovations will include lower profile devices, higher flow, greater durability, and even fully implantable devices (Figure).

Figure. Low profile circulatory support devices.

References

1. Narang N, Blumer V, Jumean MF, et al. Management of heart failure-related cardiogenic shock: Practical guidance for clinicians. JACC Heart Fail. 2023;11(7):845-851. doi: 10.1016/j.jchf.2023.04.010. PMID: 37204365.
2. Möller JE, Engstrøm T, Jensen LO, Eiskjær H, Mangner N, Polzin A, et al. Microaxial flow pump or standard care in infarct-related cardiogenic shock. N Engl J Med. 2024;390(15):1382-1393. doi: 10.1056/NEJMoa2312572. PMID: 38587239.