New Review Urges Rethink of Cardiogenic Shock Care

Cardiogenic shock care extends beyond rapid decision-making at the bedside, a new review asserts. Clearer understanding of shock’s diversity and how best to tackle its acute manifestations, as well as a long-term perspective on what should happen thereafter, may improve outcomes in this challenging scenario.

The paper, published online yesterday in JACC: Heart Failure, gathers the existing literature and, as senior author Wayne B. Batchelor, MD (Inova Heart and Vascular Institute, Falls Church, VA), told TCTMD, outlines one center’s “homegrown protocol” for a multidisciplinary, team-based approach.

Cardiogenic shock is “ubiquitous, and historically it’s been extremely difficult to move the mark in the right direction for improving outcomes,” Batchelor said. “To complicate matters, there had been challenges on how to adequately classify and define cardiogenic shock, as well some controversy on how to manage the patient from the onset of shock, even prehospital, to the emergency department, the cath lab, the critical care unit, the floor, and beyond.”

Some progress has been made. Just last year, the Society for Cardiovascular Angiography and Interventions released the first-ever standardized classification scheme for cardiogenic shock, which has been found to track well with mortality risk. Registry data have also been arriving—the National Cardiogenic Shock Initiative (NCSI), whose protocols involve the Impella (Abiomed) device, PCI, and right-heart monitoring, has suggested that a standardized approach may bear fruit. Still, cardiogenic shock has proven notoriously hard to study in randomized controlled trials.

In 2016, Inova started applying its own systemic approach to managing cardiogenic shock, said lead author Behnam N. Tehrani, MD. As part of this, the investigators looked at their own outcomes to tease out areas for improvement. Three themes emerged: fractured care, late recognition of shock, and heterogeneous practice patterns.

“Ultimately it comes down to comprehensive and longitudinal multidisciplinary team-based care. It’s agnostic of any device. It’s agnostic of any technologic therapies,” Tehrani explained, adding, “Not all shock is the same.”

To make their case, Tehrani et al reviewed the literature on cardiogenic shock’s epidemiology, economic fallout, pathophysiology, classification, and management, with sections devoted not only to acute MI but also acute decompensated heart failure and RV failure. They arrived at a proposed pathway for cardiogenic shock care, including cardiac intensive care unit (CICU) best practices.

What’s needed next, the authors say, are collaborative registries, creative approaches to RCT design, and systems of care akin to STEMI networks.

The Inova Experience

As outlined in the review, the proposed pathway for cardiogenic shock care involves several components: identification and classification of shock state, stabilization, coronary revascularization (in acute MI), comprehensive hemodynamic assessment, plus early, selective use of mechanical circulatory support (MCS) and multidisciplinary CICU care.

Decisions take into account each patient’s cardiogenic shock phenotype—eg, LV dominant, right dominant, biventricular—and how their hemodynamics will respond to particular interventions, said Tehrani. Other key aspects are specific criteria for what constitutes cardiogenic shock, both clinical factors and hemodynamic factors.

CICU management includes serial assessment of lactate, cardiac output/index (Fick and thermodilution methods), cardiac power output, and pulsatility index. If a patient is on MCS, there are serial echocardiograms as well as monitoring for hemolysis and neurovascular complications. Contraindications to MCS are anoxic brain injury, irreversible end-organ failure, prohibitive vascular access, and do-not-resuscitate orders. Treatment objectives are weaning from vasopressors/inotropes, early escalation of therapy in cases of refractory shock, and ultimately heart recovery.

Batchelor said pulling together cohesive advice on when and how to deploy MCS was a tough task.

“This has been all over the map,” he observed. “There are thought leaders in this arena who have very disparate views, some of whom are extremely strong proponents of fairly aggressive measures to use these devices and other detractors who feel that the evidence base is not supportive yet of universal use of mechanical circulatory support. And then of course there are huge biases within that realm of MCS, whereby some people have particular devices that they try to put forth and support. We intentionally tried to stand back and look at the evidence base. It’s a moving target.”

What’s important to realize overall, though, is that decisions made early on in an acute setting are “highly dependent on where we think we’re going to end up with this patient,” said Batchelor. And this is all the more reason for the expertise provided by various shock team members. At Inova, a heart failure specialist advises on whether the patient would be a candidate for a durable ventricular assist device or heart transplant. If this isn’t possible, “that needs to be declared up-front and recognized up-front, so that appropriate decisions can be made. The decision-making algorithm is entirely different for a patient who has transplant at the end of the care pathway potentially versus [someone] who doesn’t or doesn’t have other options,” he explained.

Tehrani pointed out that beyond the shock team’s standard members—an interventional cardiologist, cardiothoracic surgeon, cardiac intensivist, and advanced heart failure specialist—there is a wide net of other people from other specialties who contribute: nutrition, pharmacy, respiratory therapy, nephrology, and the list goes on. Much of the work occurs in the ICU. And while short-term protocols are crucial, it’s also important to consider the full arc of care “from admission to disposition,” Tehrani advised.

New Directions

Beyond the hospital level, said Tehrani and Batchelor, there are opportunities to improve care across regions. Physicians can champion these efforts at their institutions and push for participation in registries. Beyond the NCSI, there are smaller registries as well as the Cardiogenic Shock Working Group. The Cardiac Safety Research Consortium, a nonprofit group, is set to soon host its fourth “think tank” on how to move cardiogenic shock studies forward.

For Batchelor, what can’t be overemphasized is “the concept of 100% universal collection of comprehensive data on all patients coming into an institution” irrespective of the interventions they receive. Beyond this, registries should involve enough cases that there can be comparisons between slight differences in care, he said. To this end, he added, the Inova researchers will soon partner with investigators at the University of Utah and Sentara Healthcare.

Broadly speaking, the review highlights four main targets for future research: diagnosis (pulmonary arterial catheters, classification of cardiogenic shock), tailored therapeutics (MCS, revascularization, vasopressors/inotropes, antithrombotics), care delivery models (regionalized systems, multidisciplinary CICU teams with 24-7 coverage), and palliative care.

“We really have not had good guidance on futility. Everything is focused on saving a patient, which is key and very important, but as we go through this we have to balance prognosis, patient expectations, patient health values, and palliation,” Batchelor noted.

This is a notoriously difficult group of patients to put in a clinical trial, but that should not prevent us from doing the work that needs to be done to unequivocally prove efficacy and safety of any particular intervention. Wayne B. Batchelor

So there are questions, then, about precisely how and when palliative care should enter the picture, he continued. “How do we do this in a manner that’s humane for the patient and links the intervention with prognosis? I think that’s where the science perhaps has not quite caught up with many of these sort of high-tech, fascinating, and interesting modalities that we have available to us.”

Even for patients who survive to discharge, few studies have tracked long-term outcomes, said Tehrani. “It’s one thing to get a patient out of the hospital alive and [then] they expire within a week or two at . . . some other facility. But another if at 6 months they’re part of the community, and they’re contributing, and they’re thriving.” Six-year data from IABP-SHOCK, for instance, suggest that around 30% of patients continue to experience some or severe problems with mobility and anxiety/depression, while nearly half report some or severe pain/discomfort.

Answering all of the above questions will require cooperation across industry, regulators, researchers, patient advocates, and clinicians, said Batchelor. And it won’t be easy.

“From a clinical trialist point of view, I just think that there’s a huge opportunity for experimental trial designs,” he suggested, adding, “This is a notoriously difficult group of patients to put in a clinical trial, but that should not prevent us from doing the work that needs to be done to unequivocally prove efficacy and safety of any particular intervention.”