Circulatory Support in Cardiogenic Shock: Weaning Is Just as Important as Initiation

As multidisciplinary cardiogenic shock teams have proliferated, there has been no shortage of literature guidance on when and how to initiate temporary mechanical circulatory support (TMCS) in patients with or at risk for refractory cardiogenic shock. In contrast, however, standardized guidance on when and how to wean these patients from TMCS devices has been minimal to nonexistent.

Now a diverse team of Cleveland Clinic subspecialists has filled that void with a singular paper — “A Pragmatic Approach to Weaning Temporary Mechanical Circulatory Support” — that reviews the literature on this question, shares results from a survey of expert opinion, and presents Cleveland Clinic’s approach and algorithms for weaning TMCS support. Their work was published as a State-of-the-Art Review in JACC: Heart Failure (2021;9[9]:664-673).

“There is considerable heterogeneity in practice around when and why to wean, even within institutions,” says the paper’s senior author, Jerry Estep, MD, Medical Director of Cleveland Clinic’s Kaufman Center for Heart Failure Treatment and Recovery. “We undertook this paper with a threefold aim: to define and outline key concepts in decision-making around device weaning, to summarize the published literature and capture current expert opinion, and to share Cleveland Clinic’s approach in this realm.”

Stakes are high

The impetus was an unmet need for guidance in developing exit strategies for a high-stakes clinical scenario. TMCS is used to restore adequate tissue perfusion to stabilize patients with cardiogenic shock so that the advanced heart disease underlying the shock can be treated. Sometimes the end result is heart recovery following interventions such as stenting or valve replacement. Often, however, disease is sufficiently advanced to require heart transplantation or placement of a durable left ventricular assist device (LVAD).

“Each of these exit strategies has a narrow window of opportunity,” observes heart failure cardiologist Ziad Taimeh, MD, a co-author of the new paper and member of Cleveland Clinic’s cardiogenic shock team. “Weaning the mechanical support too early can result in destabilization, while weaning too late can lead to device complications that preclude safe transition to a subsequent exit strategy. Structured weaning strategies need to be in place to enable accurate assessment of that window of opportunity on a daily basis.”

He notes that demonstrating TMCS dependency with attempted device wean trials is included for rejustification of heart transplant listing status in the 2018 revision of the United Network for Organ Sharing policy for adult heart allocation.

“The decision to place temporary mechanical circulatory devices in hemodynamically unstable patients should not be instinctive but guided by clear, targeted support and unloading strategies that pay attention to the underlying pathological substrate — and the possible exit strategy,” adds co-author Venu Menon, MD, Director of Cleveland Clinic’s Cardiac Intensive Care Unit. “Having a systematic and thoughtful weaning strategy to enable the clinician to gauge the presence or likelihood of ventricular recovery is a central principle of adopting this approach.”

Three windows into structuring weaning strategies

The new paper provides three windows into developing structured weaning strategies:

• The literature review portion succinctly synthesizes results from 50 identified studies describing TMCS weaning or explant strategies. Findings are presented by device, including intra-aortic balloon pumps, micro-axial flow Impella devices, TandemHeart systems and veno-arterial extracorporeal membrane oxygenation (VA-ECMO).
• The expert opinion portion summarizes areas of agreement and divergence among 34 centers that responded to a survey of members of the Cardiogenic Shock and International Society of Heart and Lung Transplantation MCS Working Groups.
• The rest of the paper shares essentials of Cleveland Clinic’s approach to TMCS use, weaning and explant, including a device-tailoring algorithm for TMCS (Figure). “Our approach to cardiogenic shock involves individualized patient assessment and treatment that prioritizes early TMCS device tailoring for an upper-body ventricular-specific unloading strategy, liberation from mechanical ventilation and prevention of physical deconditioning through ambulation,” notes cardiothoracic surgeon Aaron Weiss, MD, a co-author of the paper and member of Cleveland Clinic’s cardiogenic shock team.

Figure. Cleveland Clinic’s device-tailoring algorithm for TMCS in patients with cardiogenic shock. Reprinted from JACC: Heart Failure (2021;9[9]:664-673), ©2021 The Authors. BiV = biventricular; IABP = intra-aortic balloon pump; LV/RV = left/right ventricular; oxy. = oxygenator; Pulm. = pulmonary; pVAD = percutaneous ventricular assist device; VA/VV-ECMO = veno-arterial/veno-venous extracorporeal membrane oxygenation

Principal takeaways

The authors of the paper identify a number of key takeaways, outlined below, arising from their review of evidence and opinion as well as from the Cleveland Clinic cardiogenic shock team’s experience in recent years.

Think in terms of “readiness to wean.” “One of our objectives was to raise awareness of the concept of ‘readiness to wean,’” says Dr. Estep. “There are risks related to ongoing support if patients stay on a TMCS device longer than needed. It’s important for cardiogenic shock teams to have concrete criteria defined in advance for when to start attempting to wean a patient from a given device. And these criteria should be comprehensive — reflecting clinical features, hemodynamic responses and metabolic parameters — rather than being based on just a few measures.” The paper shares guidance for defining such criteria, as well as recommendations on how to wean from various devices.

Adopt a truly tailored approach. No one TMCS device fits every patient or every stage within the continuum of cardiogenic shock. Similarly, weaning strategies differ for different devices and different stages of a patient’s disease course. “It’s important for the cardiogenic shock team to understand where they intend to go with a device, because with each device you have multiple avenues and exit strategies,” observes co-author Edward Soltesz, MD, MPH, Surgical Director of the Kaufman Center for Heart Failure Treatment and Recovery.

He cites the example of a patient who presents in hemo-metabolic collapse and requires urgent cannulation for VA-ECMO. “Their metabolic status may improve very rapidly,” he says, “at which point what they need is hemodynamic ventricular-specific support, which means they should be weaned and decannulated from VA-ECMO and transitioned to the appropriate subsequent support strategy.”

Whereas some programs may be perceived as “an ECMO program” or “an Impella program,” the goal should be to offer all TMCS devices in what Cleveland Clinic calls a tailored approach to cardiogenic shock. “We have all the devices available and use them to achieve patient stability in the least invasive way and accomplish our goal for the patient from a ventricular support standpoint,” Dr. Soltesz explains. “When needed, it’s appropriate for a smaller center to reach out to a tertiary or quaternary center on a challenging case rather than deeming a patient not weanable.”

Approach weaning as a team exercise. As Cleveland Clinic’s cardiogenic shock team has evolved, it has become broader and more collaborative, particularly in decision-making around device weaning. “To properly manage these complex cases, it is imperative to involve a multidisciplinary team of experts, including cardiologists and cardiac surgeons specializing in heart failure and transplantation, critical care cardiologists, interventional cardiologists, perfusionists, and nurses and advanced practice providers specializing in these areas,” says Dr. Taimeh.

At Cleveland Clinic, these clinicians gather at a virtual huddle every afternoon (see photo at top) to make decisions about — and adjustments to — device strategies for their cardiogenic shock patients. At these huddles the multidisciplinary team reviews key clinical, hemodynamic and metabolic features — blood pressure and heart rate, cardiac performance as assessed by right heart catheterization, lactate levels, end-organ function, medication requirements and more — to assess patient stability in the context of Cleveland Clinic’s algorithms for readiness to wean. “The multidisciplinary expertise on hand allows us to quickly pivot to new strategies if needed,” Dr. Estep notes. “The establishment of the team and the regularity of the huddles ensure that we all speak the same language and are following shared criteria.”

Recognize that weaning is not a single event. “Weaning is a constant reevaluation of a patient’s readiness to move to the next, most appropriate support therapy,” Dr. Soltesz says. Cleveland Clinic’s cardiogenic shock team continuously monitors patients over defined periods to assess their likelihood of maintaining stability on lower levels of support, often with rapid or slow device wean trials. “Sometimes the assessment will result in device removal,” Dr. Soltesz continues. “Sometimes it will involve therapy de-escalation or even escalation. Other times it will lead to transitioning to a different temporary support device or pivoting to transplant or a durable LVAD. Weaning is a process, not just a single event.”

Next up: Laying groundwork for prospective data insights

The authors note that the historical dearth of guidance on TMCS weaning stems in part from the challenges of researching this issue. Sample sizes are small, patient phenotypes vary widely and granular data are needed across a broad set of patient measures.

To overcome these challenges, Cleveland Clinic is leveraging its electronic medical record to develop a prospective cardiogenic shock database to capture discrete data before, during and after device therapy to analyze short- and long-term patient outcomes. “It will encompass the various device strategies and help us continually improve our processes as well as share best practices with other cardiogenic shock teams,” says Dr. Weiss.