What is the recommended hemoglobin (Hb) target for patients post-myocardial infarction (MI)?

Hemoglobin Target for Myocardial Infarction

For patients with acute myocardial infarction and anemia (hemoglobin <10 g/dL), target a hemoglobin level of approximately 10 g/dL using a liberal transfusion strategy rather than allowing levels to drop to 7-8 g/dL. 1

Evidence-Based Transfusion Strategy

The 2025 ACC/AHA/ACEP/NAEMSP/SCAI guidelines recommend a liberal transfusion approach for MI patients with anemia, based on the landmark MINT trial which randomized 3,504 patients with acute MI and hemoglobin <10 g/dL. 1 This represents the most definitive guidance available, superseding older restrictive approaches used in non-cardiac populations.

Key Findings from MINT Trial

The restrictive strategy (transfusing only when hemoglobin fell below 7-8 g/dL) showed concerning trends toward worse outcomes compared to the liberal strategy (transfusing when hemoglobin fell below 10 g/dL): 1, 2

• Primary outcome (death or recurrent MI at 30 days): 16.9% restrictive vs. 14.5% liberal (RR 1.15,95% CI 0.99-1.34) 1, 2
• All-cause mortality: 9.9% restrictive vs. 8.3% liberal (RR 1.19,95% CI 0.96-1.47) 1, 2
• Cardiac death: 5.5% restrictive vs. 3.2% liberal (RR 1.74,95% CI 1.26-2.40) - statistically significant 1

Critical Care Guidelines Alignment

The 2024 American College of Chest Physicians guidelines for critically ill adults specifically address ACS patients, noting that while the MINT trial's primary endpoint did not reach statistical significance, the consistent point estimates favoring liberal transfusion and the significantly higher cardiac death rate with restrictive strategy raise concern that allowing hemoglobin to drop to 7-8 g/dL may increase adverse outcomes. 1

Patient-Level Meta-Analysis Confirms Findings

A 2025 patient-level meta-analysis pooling 4,311 patients from four trials demonstrated: 3

• 30-day cardiac death: 5.5% restrictive vs. 3.7% liberal (RR 1.47,95% CI 1.11-1.94) - statistically significant
• 6-month all-cause mortality: 20.5% restrictive vs. 19.1% liberal (HR 1.08,95% CI 1.05-1.11) - statistically significant

High-Risk Subgroups Requiring Particular Attention

Patients with Baseline Heart Failure

Patients with pre-existing heart failure showed particularly poor outcomes with restrictive transfusion: 4

• Death or heart failure at 30 days occurred in 18.0% of HF patients vs. 10.0% without HF
• Restrictive transfusion resulted in numerically higher rates of death or HF in patients with baseline HF (rate ratio 1.20,95% CI 0.99-1.45) compared to those without HF 4

Progressive Risk with Lower Thresholds

A target trial emulation analysis examining four different hemoglobin thresholds (<10, <9, <8, <7 g/dL) demonstrated progressive increases in 30-day death/MI risk as thresholds decreased: 5

• <10 g/dL threshold: 14.8% risk
• <9 g/dL threshold: 15.1% risk
• <8 g/dL threshold: 15.9% risk
• <7 g/dL threshold: 18.3% risk

This dose-response relationship supports targeting the higher threshold of 10 g/dL. 5

Clinical Implementation Algorithm

Step 1: Identify anemic MI patients

• Check hemoglobin on admission in all MI patients 1
• Anemia defined as hemoglobin <10 g/dL in the MI population 1, 2

Step 2: Initiate liberal transfusion strategy

• Transfuse when hemoglobin falls below 10 g/dL 1, 2
• Target maintaining hemoglobin around 10 g/dL 1

Step 3: Adjust for specific clinical scenarios

• Patients with volume overload: May delay transfusion temporarily 1
• End-stage renal disease: May delay until day of dialysis 1
• Active uncontrolled bleeding: Address bleeding source first 1

Step 4: Monitor for transfusion complications

• Assess for volume overload, particularly in heart failure patients 4
• Monitor for transfusion reactions 1

Important Caveats

Do not use restrictive thresholds (7-8 g/dL) from non-cardiac critical care populations - the myocardium's oxygen demands during acute ischemia make these lower targets potentially harmful. 1 The significantly elevated cardiac death rate with restrictive transfusion (RR 1.74) represents a clinically meaningful harm signal that cannot be ignored. 1

Avoid prophylactic transfusion above 10 g/dL - there is no evidence supporting transfusion when hemoglobin is ≥10 g/dL, and overtransfusion carries risks of volume overload and increased blood viscosity. 1

Consider patient symptoms and physiologic variables alongside hemoglobin levels when making transfusion decisions, particularly for borderline values between 8-10 g/dL. 1

Prognostic Significance

Lower hemoglobin levels independently predict worse outcomes in MI patients. A retrospective study of 1,841 consecutive MI patients demonstrated 30-day mortality of 21.6% in patients with admission hemoglobin ≤10 g/dL versus 9.3% in those with hemoglobin >10 g/dL (p<0.001), with hemoglobin remaining an independent predictor after multivariate adjustment (HR 1.76,95% CI 1.08-2.85). 6