PHILADELPHIA – Blood transfusions can kill surgery patients, a finding that puts the onus on surgeons to administer transfusions only when absolutely necessary, according to Dr. Gaetano Paone.
An analysis of more than 31,000 patients who had isolated coronary artery bypass grafting surgery in Michigan during January 2006–June 2010 showed that receiving one or more transfusion conferred a nearly threefold higher risk of operative mortality than did not receiving blood, Dr. Paone reported at the meeting.
“There is great variability in the rates of transfusions across institutions,” noted Dr. Paone, a cardiac surgeon at Henry Ford Hospital in Detroit, in an interview. In some places, the transfusion rates of isolated CABG patients are 15%, and other places have rates of more than 90%. “That suggests it's quite discretionary.”
Dr. Paone and his associates examined data on 31,818 patients who underwent isolated CABG during the study period at any one of the 33 Michigan hospitals that perform cardiac surgery. The data came from records maintained by the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative.
The researchers calculated the mortality risk faced by each patient using the STS-PROM (Society of Thoracic Surgeons Predicted Risk of Mortality) model, which takes into account 30 preoperative patient variables. They stratified the patients into four risk groups based on their scores, which represent the percent risk for 30-day perioperative mortality (less than 2%, 2%–5%, 6%–10%, and more than 10%), and divided patients into the 55% who received transfusions and the 45% who did not receive any blood. Overall operative mortality in the patients studied was 2%. As expected, operative mortality was higher in patients who received a transfusion (3.3%) than in those who did not (0.6%) – a significant sixfold difference.
The analysis also showed that the significant link between increased mortality and transfusion remained fairly constant across all four risk strata in the study, ranging from a twofold increased risk in patients with an STS-PROM score of 2%–5%, to a fourfold increased risk in patients with a score of more than 10%, said Dr. Paone, who had no disclosures.
To see a video interview with Dr. Paone, scan this QR code using your smartphone.