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

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. 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. 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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