Lactate Clearance May Act as ‘Early Warning Sign’ in Cardiogenic Shock

Lactate clearance can be used to predict survival in patients with cardiogenic shock and aid in management decisions, and experts are calling for establishing lactate clearance as a standardized, objective, time-based marker that could be used across hospitals and health systems, according to a new initiative by the Society for Cardiovascular Angiography & Interventions (SCAI).

Writing group chair Srihari S. Naidu, MD (Westchester Medical Center, Valhalla, NY), said the concept is a natural extension of the work that has been evolving in the field of cardiogenic shock care in recent years.

“Shock is a cycle of worsening hemodynamics and worsening end-organ dysfunction and ultimately an inflammatory metabolic state where the mortality is very high,” he told TCTMD. “We’ve realized that even though our understanding of shock has progressed in terms of etiologies and phenotypes and different ways of treating shock, the Achilles’ heel is how to assess these patients in the very early hours of shock to make sure the intervention is actually improving the patient, and if not, [then] we can rapidly shift gears.”

In those first 6 to 8 hours after the diagnosis of cardiogenic shock has been made, Naidu said, measuring lactate clearance allows for quick assessment so the shock team can “put their heads together and figure out what more can be done.”

The evidence base for lactate clearance comes from multiple RCTs, including IABP-SHOCK IIl, in which lactate levels at 8 hours were the strongest predictor of mortality among all variables analyzed; VA-ECLS, in which lactate clearance was associated with survival across a variety of disease states, including cardiac arrest, sepsis, and cardiogenic shock; and the DOREMI trial, in which complete clearance of lactate, percentage lactate clearance, and percentage lactate clearance per hour were all independent predictors of survival in a shock population.

SCAI is calling the initiative Door-to-Lactate Clearance (DLC), and they propose measuring lactate every 2 to 3 hours after the shock diagnosis has been made to assess response to the initial and subsequent interventions. In a paper simultaneously published in JSCAI to coincide with Naidu’s presentation at SCAI Shock 2025, the writing committee said the goal is to get lactate levels below 2 mmol/L within 24 hours of diagnosis of stage C/D/E on the SCAI shock classification.

This area is crying out for people to think deeply and change the treatment paradigm to improve patient care. Mitchell Psotka

Commenting for TCTMD, Mitchell Psotka, MD, PhD (Inova Heart and Vascular Institute, Falls Church, VA), said the DLC initiative provides optimism for a population that has seen little innovation in care in decades.

“Besides improvements in system-based care, team-based care, and regional shock networks, which are all systematic logistic issues, the treatment paradigm on an individual patient basis has not changed dramatically. This area is crying out for people to think deeply and change the treatment paradigm to improve patient care,” he said.

Lactate clearance, he added, “is a reasonable hypothesis that may or may not turn out to be appropriate, but without scientific testing of a new hypothesis, we don’t make any progress. We’ve been repeatedly testing the same ideas that have not worked out.”

The DLC Initiative

In the paper, the writing committee lays out what is known about the superior predictability of serial lactate levels compared with a single baseline lactate. These data come from RCTs, registries, and meta-analyses, all showing better survival when lactate is cleared rapidly.

They note that while some may argue that the improvement seen after lactate clearance is an  association without evidence to back it, monitoring lactate makes intuitive sense.

“Hence a DLC initiative focusing on door-to-lactate clearance, irrespective of the etiology of [cardiogenic shock], its starting value, and agnostic to the treatment modality(s) chosen can potentially serve as an important goal for hospitals similar to what was historically proposed and subsequently achieved with the introduction to door-to-balloon times (DBT) in STEMI care,” the committee adds.

They make it clear that the value of lactic acid in management depends on where the sample is taken from and the analyzer. In clinical practice, “repeated measurements using the same location allow care teams to reliably establish trends in value” that are relevant regardless of time, day of presentation, or diagnosis.

Another important consideration is that DLC is practical for regional referral centers as well as tertiary advanced care centers. The committee stresses the importance of being able to measure lactate in real-time in all clinical settings where shock is evaluated and managed, including by emergency response services and emergency departments, and in cardiac catheterization laboratories, operating rooms, and intensive care units.

“The [regional referral center] without the capability to escalate care to advanced levels needs to be particularly cognizant of the failure of lactate clearance as an indication to rapidly re-evaluate the patient, escalate care or consider transfer,” the committee notes. For tertiary centers receiving a transferred shock patient, the DLC gives them a heads-up about escalation options and helps with protocolized planning. Importantly, DLC may also prevent inappropriate escalation of care in some instances.

“We are late to the game, in my opinion, in utilizing lactate in cardiogenic shock,” Naidu said. “It has been used in other forms of shock, and now we’re beginning to build the literature here.”

Data, Devil in the Details, and Doing Better

The group recognizes that some in the shock community may question whether it might not be better to wait for stronger evidence before encouraging putting DLC protocols into action. For Naidu, acting on lactate is a means to get ahead of the curve in treating cardiogenic shock that is on par with suggestions to enroll shock patients who are unable to consent in trials because data are so badly needed.

“Sometimes you have to bend some of these more stringent rules of data evidence because the disease process is just so [extreme],” he said. “Therefore, to get the data and to try to do right by the patient, we have to move a little bit faster.”

For now, the committee encourages accumulation of real-world registry evidence to validate the hypothesis while calling on clinical investigators and registry organizers “to incorporate and evaluate serial lactate and DLC prospectively, to see whether this rather simple intervention translates to improved survival.”

What we’re saying is this is like an early warning sign that something is not going right, but it has immediacy to it. Srihari S. Naidu

While the initiative is admirable, Psotka believes the devil may be in the details.

“Patients with cardiogenic shock are a pretty heterogeneous group and it’s not always clear what the appropriate intervention is to try to bring the lactate down in that time course,” he said. “The tricky part of doing this is going to be: how is the decision-making made to bring down [the levels]? Are most hospitals in this country actually capable of performing these kind of serial measurements on lactate, which I am not sure is truly the case, and then [ensuring] that this is done in a robust way to actually test this hypothesis.”

Psotka said while much thinking out of the box may be needed to further the initiative, a likely scenario that will be needed is a large consortium of centers that come together and figure out funding for an RCT to prove whether or not DLC works and if it is truly the best indicator or biomarker to use in this population.

“The real challenge of [DLC] is not drawing the lactate. It’s challenging the community to use their shock teams and their brains to try to figure out why that patient’s getting worse, and to avail themselves of whatever resources and protocols they have at their institution to try to get the patient better,” Naidu added.