Transfusion Requirements in Cardiac Surgery III - TRICS III

Contribution To Literature:

The TRICS III trial showed that a restrictive red-cell transfusion strategy (hemoglobin <7.5 mg/dl) resulted in fewer red-cell transfusions than a more liberal red-cell transfusion strategy (hemoglobin <9.5 mg/dl) and is noninferior for major clinical outcomes among moderate- to high-risk patients undergoing on-pump cardiac surgery.

Description:

The goal of the trial was to assess the efficacy of a restrictive blood transfusion strategy to a more liberal one among moderate- to high-risk patients undergoing cardiac surgery.

Study Design

Patients scheduled for on-pump cardiac surgery were randomized in a 1:1 fashion to either a restrictive transfusion strategy (only if hemoglobin was <7.5 mg/dl) or a more liberal strategy (hemoglobin <9.5 mg/dl in the operating room and intensive care unit [ICU], and <8.5 mg/dl on the floors). Assigned strategy had to be adhered to until hospital discharge or 28 days (whichever came first).

  • Total number of enrollees: 4,860
  • Duration of follow-up: 28 days
  • Mean patient age: 72 years
  • Percentage female: 35%
  • Percentage with diabetes: 27%

Inclusion criteria:

  • Age ≥18 years
  • Scheduled for on-pump cardiac surgery
  • Preoperative additive EuroSCORE I: ≥6

Exclusion criteria:

  • Unable or declined to receive blood products
  • Involved with preoperative autologous donation program
  • Undergoing heart transplantation
  • Surgery only for insertion of left ventricular assist device
  • Pregnant or lactating

Other salient features:

  • EuroSCORE (median): 7.9
  • Previous percutaneous coronary intervention: 13%
  • Left ventricular ejection fraction at least moderately reduced: 38%
  • Baseline hemoglobin: 13.1 mg/dl
  • Type of surgery: CABG-only: 26%, CABG + valve: 19%, valve surgery: 29%
  • Duration of cardiopulmonary bypass: 120 minutes

Principal Findings:

The primary outcome, all-cause mortality, nonfatal myocardial infarction (MI), stroke, new-onset renal failure with dialysis, and between-hospital admission and discharge/28 days, for restrictive vs. liberal transfusion strategies, was 11.4% vs. 12.5% (odds ratio 0.90, 95% confidence interval 0.76-1.07, p for noninferiority < 0.001).

  • All-cause mortality: 3.0% vs. 3.6%
  • MI: 5.9% vs. 5.9%
  • Stroke: 1.9% vs. 2.0%
  • New renal failure: 2.5% vs. 3.0%

On subgroup analysis, the primary endpoint was significantly reduced among patients ≥75 years (p for interaction = 0.004).

Secondary outcomes for restrictive vs. liberal transfusion strategies:

  • ≥1 unit red blood cells transfused: 52.3% vs. 72.3%, p < 0.05
  • Plasma transfusion: 23.5% vs. 27.1%, p < 0.05
  • Median length of stay (LOS): 8 vs. 8, p < 0.05
  • ICU median LOS: 2.1 vs. 1.9, p < 0.05
  • Infection: 5.0% vs. 4.2%, p > 0.05

Six-month outcomes: The primary outcome for restrictive vs. liberal transfusion was 17.4% vs. 17.1% (p = 0.006 for noninferiority). Mortality: 6.2% vs. 6.4%, MI: 7.3% vs. 7.3%, hospital readmission: 26.2% vs. 23.6% (all p > 0.05).

Interpretation:

The results of this trial indicate that a restrictive red-cell transfusion strategy (for hemoglobin <7.5 mg/dl) resulted in fewer red-cell transfusions than a more liberal red-cell transfusion strategy (hemoglobin <9.5 mg/dl) and is noninferior for major clinical outcomes among moderate- to high-risk patients undergoing on-pump cardiac surgery. Results were sustained up to 6 months of follow-up.

This trial confirms earlier observations that blood transfusions to an arbitrary higher threshold may not always be beneficial and could be associated with potential harm. A more restrictive strategy appeared to be particularly beneficial among elderly patients. These are important findings and will likely influence perioperative guidelines.

References:

Mazer CD, Whitlock RP, Fergusson DA, et al., on behalf of the TRICS Investigators and Perioperative Anesthesia Clinical Trials Group. Six-Month Outcomes After Restrictive or Liberal Transfusion for Cardiac Surgery. N Engl J Med 2018;Aug 26:[Epub ahead of print].

Presented by Dr. C. David Mazer at the European Society of Cardiology Congress, Munich, Germany, August 26, 2018.

Mazer CD, Whitlock RP, Fergusson DA, et al., on behalf of the TRICS Investigators and Perioperative Anesthesia Clinical Trials Group. Restrictive or Liberal Red-Cell Transfusion for Cardiac Surgery. N Engl J Med 2017;377:2133-44.

Presented by Dr. C. David Mazer at the American Heart Association Annual Scientific Sessions (AHA 2017), Anaheim, CA, November 12, 2017.

Clinical Topics: Cardiac Surgery, Geriatric Cardiology, Invasive Cardiovascular Angiography and Intervention

Keywords: AHA17, AHA Annual Scientific Sessions, Blood Transfusion, Coronary Artery Bypass, Cardiac Surgical Procedures, Erythrocyte Transfusion, Geriatrics, Hemoglobins, Intensive Care Units, Length of Stay, Myocardial Infarction, Renal Insufficiency, Stroke


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