What is the clinical evidence from this study?

Study design: Observational. Population: Cardiogenic shock (n=628). Intervention: High lactate clearance (≥ 64% at 24 h) vs. Low lactate clearance (< 64% at 24 h). Primary outcome: In-hospital mortality (OR 0.42, 95% CI 0.30-0.60, p=<0.001).

October 18, 2021Open Access

Clinical significance of lactate clearance in patients with cardiogenic shock: results from the RESCUE registry

Q: What are the key findings of this study?

High 24-hour lactate clearance (≥ 64%) was associated with a significantly lower risk of in-hospital mortality compared to low lactate clearance in patients with cardiogenic shock (OR 0.42).

Key Result

High 24-hour lactate clearance (≥ 64%) was associated with a significantly lower risk of in-hospital mortality compared to low lactate clearance in patients with cardiogenic shock (OR 0.42).

Study Design

Type

Observational (n=628)

Multicenter

Yes

Structured PICO

Does high 24-hour lactate clearance (≥64%) predict lower in-hospital and 12-month mortality in patients with cardiogenic shock?

Population

628 patients with cardiogenic shock (age ≥19 years, systolic blood pressure <90 mmHg for 30 min or requiring inotrope/vasopressor support, with pulmonary congestion and signs of impaired organ perfusion), median age 66, 66.2% male, enrolled from 12 tertiary centers in the Republic of Korea. Excluded: out-of-hospital cardiac arrest, other causes of shock, death within 24 hours, or unavailable serial lactate.

Intervention

High 24-hour lactate clearance (≥64% reduction from initial lactate value)

Comparator

Low 24-hour lactate clearance (<64% reduction from initial lactate value)

Outcome

In-hospital mortalityhard clinical

In patients with cardiogenic shock, a 24-hour lactate clearance of ≥64% is strongly associated with improved in-hospital and 12-month survival, particularly in those with an initial lactate >5 mmol/L.

Main Result

Effect estimate: OR 0.42 (95% CI 0.30-0.60)

Absolute Event Rate: 25.5% vs 42.7%

p-value: p=<0.001

Limitations

Non-randomized and observational design, potentially affecting results through selection bias and confounding factors
Most patients presented with an ischemic etiology, and patients with non-ischemic causes were heterogeneous and of limited sample size
Registry did not include hemodynamic parameters, such as cardiac index or pulmonary capillary wedge pressure measured by a pulmonary arterial catheter
Removal of serum lactate could occur in the liver or kidney, so the presence of underlying disease in those organs or use of continuous renal replacement therapy could affect lactate clearance
Significantly different serum glucose values and vasoactive inotropic scores between the two groups may have affected results
Treatment for cardiogenic shock was left to the physician's discretion

Abstract

BACKGROUND: Limited data are available on the clinical significance of lactate clearance (LC) in patients with cardiogenic shock (CS). This study investigated the prognostic role of LC in CS patients. METHODS: We analyzed data from 628 patients in the RESCUE registry, a multicenter, observational cohort enrolled between January 2014 and December 2018. Univariable logistic regression analysis was performed to determine the prognostic implications of 24 h LC, and then patients were divided into two groups according to the cut-off value of 24 h LC (high lactate clearance HLC group vs. low lactate clearance LLC group). The primary outcome was in-hospital mortality. We also assessed all-cause mortality at 12 month follow-up and compared the prognostic performance of 24 h LC according to initial serum lactate level. RESULTS: In the univariable logistic regression analysis, 24 h LC was associated with in-hospital mortality (odds ratio 0.989, 95% confidence interval CI 0.985-0.993, p 5 mmol/L than in those with serum lactate ≤ 5 mmol/L (c-statistics of initial serum lactate > 5 mmol/L = 0.782 vs. c-statistics of initial serum lactate ≤ 5 mmol/L = 0.660, p = 0.011). CONCLUSIONS: Higher LC during the early phase of CS was associated with reduced risk of in-hospital and 12 month all-cause mortalities. Patients with LC ≥ 64% during the 24 h after CS onset could expect a favorable prognosis, especially those with an initial serum lactate > 5 mmol/L. TRIAL REGISTRATION: RESCUE (REtrospective and prospective observational Study to investigate Clinical oUtcomes and Efficacy of left ventricular assist device for Korean patients with cardiogenic shock), NCT02985008, Registered December 5, 2016-retrospectively and prospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT02985008.

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