3.2 Effect of red blood cell transfusion on outcomes

3.2.2 Acute coronary syndrome

Evidence Statements – acute coronary syndrome
ES2.2	In ACS patients with a Hb concentration >100 g/L, RBC transfusion may be associated with a higher risk of mortality, proportional to Hb concentration.
ES2.3	In ACS patients with an admission Hb concentration <100 g/L, RBC transfusion may be associated with a lower risk of mortality.	X
ES2.4	In ACS patients with a nadir Hb concentration <80 g/L, RBC transfusion may be associated with a lower risk of mortality.			X
ES2.5	In ACS patients with a nadir Hb concentration of 80 – 100 g/L, RBC transfusion is not associated with an altered mortality risk.			NA
ES2.6	In patients with ACS, RBC transfusion may be associated with an increased risk of recurrence (up to 6 months) of MI.		NA

ACS, acute coronary syndrome; ES, evidence statement; Hb, haemoglobin; MI, myocardial infarction; RBC, red blood cell

=A; =B; =C; X=D, NA,not applicable (see Table 2.1)

Recommendation – acute coronary syndrome

R1 Grade C	In ACS patients with a Hb concentration >100 g/L, RBC transfusion is not advisable because of an association with increased mortality.

Practice Points – acute coronary syndrome

PP5	In patients with ACS and a Hb concentration <80 g/L, RBC transfusion may be associated with reduced mortality and is likely to be appropriate. (See PP1 and PP2).
PP6	In patients with ACS and a Hb concentration of 80 – 100 g/L, the effect of RBC transfusion on mortality is uncertain and may be associated with an increased risk of recurrence of MI. Any decision to transfuse should be made with caution and based on careful consideration of the risks and benefits. (See PP1 and PP2).

ACS, acute coronary syndrome; Hb, haemoglobin; MI, myocardial infarction; PP, practice point; R, recommendation; RBC, red blood cell

In patients with ACS, four retrospective cohort studies (Level III-2) assessed the relationship between mortality and transfusion at varying Hb concentrations.^21,84-86 Although the included studies analysed the data using a range of haematocrit or Hb categories, the results have been consolidated into specific Hb ranges to best inform clinical practice. The results of these studies consistently indicate that in ACS patients with a Hb concentration >100 g/L, RBC transfusion may be associated with a higher risk of mortality, proportional to Hb concentration. In ACS patients with a Hb concentration of 80 – 100 g/L, RBC transfusion is not associated with an altered mortality risk, and may be associated with an increased risk of recurrence of MI.

In patients with a Hb concentration of <80 g/L, the association between RBC transfusion and mortality is less clear. The results of Wu⁸⁶ and Sabatine²¹ showed reduced mortality in patients receiving transfusions at lower admission Hb concentrations; however, the studies by Rao⁸⁷ and Alexander84 found that transfusion at lower nadir Hb concentrations was not associated with reduced mortality. The CRG considered that nadir Hb may be more relevant than admission Hb for clinical decision making.

An additional study by Shishehbor⁸⁸ reported that, in patients with ACS, RBC transfusion may be associated with an increased risk of recurrence of MI.