In Focus: An Algorithm for Mechanical Circulatory Support (MCS) Devices | Tami Atkinson, MD, Joaquin Cigarroa, MD, and Tanveer Rab, MD

CardioSource WorldNews Interventions | Mechanical circulatory support (MCS) devices have been used to stabilize patients with cardiogenic shock and high-risk percutaneous coronary interventions (HR-PCI) for decades. While the intra-aortic balloon pump (IABP) has been the mainstay, percutaneous mechanical circulatory support devices such as veno-arterial extracorporeal membrane oxygenation (VA-ECMO), Impella, and TandemHeart have been developed and offer higher levels of hemodynamic support.1,2 With the application of percutaneous coronary intervention (PCI) to higher risk and hemodynamically unstable patients, the role for MCS has expanded.3 MCS devices offer significant improvement in hemodynamics with less hypotensive events and improved cardiac power compared to IABP.4-7 While hemodynamic improvement has not translated into a mortality benefit, it enhances the operator’s ability to provide complete revascularization in challenging subsets of patients.8 Recently, the FDA expanded the indications for Impella devices to include their use in cardiogenic shock after myocardial infarction or open-heart surgery.

With multiple device therapies available, decision-making in complex and hemodynamically unstable patients is challenging. An algorithm (attached illustration) recently published in JACC Cardiovascular Interventions, was developed to guide interventional cardiologists in decision making for MCS device therapy in patients undergoing PCI with high-risk features or cardiogenic shock.9 The first step recommends prompt identification of patients with cardiogenic shock, cardiac arrest, or high-risk features. When feasible, the next step endorses a multidisciplinary heart team consultation, which encompasses interventional cardiology, cardiothoracic surgery, advanced heart failure and intensive care physicians. After heart team consultation, the operator can work through the algorithm for appropriate device selection prior to proceeding with percutaneous coronary intervention. Operators must be proficient in device placement as well as understand indications and contraindications to device therapy.

Cardiogenic shock (CS) represents a spectrum of disease, which can be associated with hypoxemic right ventricular failure, left ventricular failure or biventricular failure. In this algorithm, CS was classified into three categories, pre/early shock, shock, and severe shock defined by clinical, hemodynamic, and vasoactive medication support.9 Identification of CS severity is critical for early initiation of hemodynamic support in order to avoid crashing onto support. Often a right and/or left heart catheterization is useful to understand a patient’s hemodynamics as defined by the parameters in the algorithm. In patients presenting with pre/early shock and shock, intra-aortic balloon pump should be considered for initial support. As patients move into severe shock criteria, higher levels of hemodynamic support are required with Impella, VA-ECMO or TandemHeart depending on their associated conditions. Device therapy must be tailored to the source of cardiogenic shock. For patients with severe shock and hypoxemia, VA-ECMO remains the initial therapy of choice in order to provide full cardiopulmonary support. Isolated right ventricular failure can be supported using a TandemHeart RVAD or Impella RP, whereas biventricular failure requires support of both the right and left ventricle with either VA-ECMO or combined right and left support devices with Impella CP and Impella RP.10-12 Patients who sustain an out-of-hospital cardiac arrest with return of spontaneous circulation (ROSC) should also be re-evaluated under the shock category to assess for hemodynamic support requirements prior to proceeding with percutaneous coronary intervention. If a patient, experiences a cardiac arrest without ROSC within 10 minutes, the ACC/AHA guidelines list VA-ECMO (ECPR) as a Class IIb indication.13 Regardless of the device used, hemodynamic reassessment with short feedback loops to assess for escalation of therapy is required.

Identifying patients with high-risk features is critical when performing PCI. With the advent of trans-catheter valve replacement (TAVR) and an aging population, patients referred for PCI are more complex. In prior studies, high-risk features have included unprotected left main coronary artery disease, three vessel coronary artery disease, (SYNTAX > 33), left ventricular ejection fraction < 35%, or last remaining patent vessel.1,4,14-17 Other clinical and anatomic factors need to be considered when performing PCI especially co-morbidities such as congestive heart failure and valvular heart disease. Pre-procedural planning is essential for HR- PCI, which is not always feasible in the setting of cardiogenic shock. Steps for successful HR- PCI includes defining access site and assessing baseline hemodynamics. Femoral angiography should be performed and if not technically feasible other options such as axillary or transcaval access should be considered. If access options are limited, then an IABP can be used.

It is critical to re-emphasize the importance of early utilization of MCS devices rather than waiting until the patient decompensates. In patients undergoing PCI with cardiogenic shock, post-cardiac arrest or high-risk features, hemodynamics require close monitoring with escalation of therapy as needed. Operators and institutions must become familiar and competent with at least two device strategies to provide safe and efficient care to patients undergoing PCI with cardiogenic shock or high-risk features due to the learning curve with newer devices. MCS device therapy requires a team based approach and institutional systems must be in place for post-procedure recovery and device management when caring for patients with cardiogenic shock, cardiac arrest, and HR-PCI.


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Joaquin Cigarroa, MD, and Tanveer Rab, MD, are both members of the Interventional Council leadership committee of the ACC.

Read the full July/August issue of CardioSource WorldNews Interventions at

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Aortic Surgery, Cardiac Surgery and Heart Failure, Acute Heart Failure, Mechanical Circulatory Support

Keywords: CardioSource WorldNews Interventions, Extracorporeal Membrane Oxygenation, Heart-Assist Devices, Hemodynamics, Intra-Aortic Balloon Pumping, Myocardial Infarction, Percutaneous Coronary Intervention, Shock, Cardiogenic

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