Cath Lab Digest

Each year, >17 million red-cell units are collected in the United States, and 15 million units are transfused. The elderly and surgical patients are most often the recipients of blood transfusions, yet, according to researchers, the indications for postoperative transfusion have not been adequately studied. One study did demonstrate that among adults in intensive care units, there was a nonsignificant decrease in 30-day mortality with a restrictive transfusion strategy compared with a liberal strategy (18.7% vs 23.3%).

Noting that the effect of a restrictive transfusion strategy on functional recovery or the risk of myocardial infarction has not been well documented, the researchers conducted a study titled FOCUS (Transfusion Trigger Trial for Functional Outcomes in Cardiovascular Patients Undergoing Surgical Hip Fracture Repair). FOCUS was designed to test the hypothesis that compared with a restrictive transfusion strategy (a hemoglobin level of <8 g/dL), a higher threshold for blood transfusion (a hemoglobin level of 10 g/dL) would improve functional recovery and reduce morbidity and mortality. They reported study results online in the New England Journal of Medicine [10.1056/NEJMoa1012452].

The researchers enrolled patients at 47 clinical sites in the United States and Canada from July 19, 2004, through February 28, 2009. Inclusion criteria included being ≥50 years of age, undergoing primary surgical repair of a hip fracture, and having clinical evidence of or risk factors for cardiovascular disease. Patients were eligible if they had a hemoglobin level of <10 g/dL within 3 days of surgery.

The study’s primary outcome was death or an inability to walk across a room (10 ft) without human assistance on 60-day follow-up. Secondary outcomes included a combined outcome of in-hospital myocardial infarction, unstable angina, or death for any reason.

Patients were randomized to either the liberal-strategy group or the restrictive-strategy group. Those in the liberal-strategy group received 1 unit of packed red cells and additional blood as needed to maintain a hemoglobin level of ≥10 g/dL; those in the restrictive group received transfusions if they developed symptoms or signs of anemia or at the discretion of their physician if their hemoglobin level fell below 8 g/dL.

The researchers screened 14,438 patients; of those, 1007 were assigned to the liberal-strategy group and 1009 to the restrictive-strategy group. After withdrawals, losses to follow-up, and 1 incomplete follow-up ascertainment, follow-up data for the primary analysis were obtained for 99.2% of patients. Mean age of study participants was 81.6 years, and cardiovascular disease was present in 62.9%. Baseline characteristics were similar in the 2 groups.

In the liberal-strategy group, the median number of units transfused was 2.0; in the restrictive-strategy group, the median number was 0. In the restrictive-strategy group, 59.0% of patients did not receive a transfusion after randomization.

For the primary outcome of death or inability to walk 10 feet without human assistance, the rates were similar in the 2 groups: 35.2% in the liberal-strategy group versus 34.7% in the restrictive-strategy group; P=.90. The odds ratio for the primary outcome associated with the liberal strategy as compared with the restrictive strategy was 1.01 (95% confidence interval [CI], 0.85-1.22), for an absolute risk difference of 0.5 percentage points (95% CI, −3.7 to 4.7).

The analysis found a significant interaction according to patients’ sex, with an odds ratio for men in the liberal-strategy group of 1.45 (95% CI, 1.00-2.10) versus 0.91 (95% CI, 0.74-1.13) for women in the liberal-strategy group; P=.03.

In the liberal-strategy group, the rates of in-hospital acute coronary syndrome or death were 4.3%, compared with 5.2% in the restrictive-strategy group (absolute risk difference, −0.9%). Rates of death on 60-day follow-up were 7.6% in the liberal-strategy group and 6.6% in the restrictive-strategy group (absolute risk difference, 1.0%). The rates of other complications were similar in the 2 groups.

In summary, the researchers stated: “A liberal transfusion strategy, as compared with a restrictive strategy, did not reduce rates of death or an inability to walk independently on 60-day follow-up or reduce in-hospital morbidity in elderly patients at high cardiovascular risk.”

—Tori Socha