February 26, 2014 – Matthew Sherwood, MD, led a team of DCRI and Yale researchers in a retrospective cohort study of treatment patterns in transfusion.
Patterns of red cell blood transfusion in patients undergoing percutaneous coronary intervention (PCI) vary widely across the United States, and these transfusions are associated with an increased risk of in-hospital adverse events.
That is the conclusion of a new study by the DCRI’s Matthew Sherwood, MD (pictured); Eric Peterson, MD, MPH; Sunil Rao, MD; and colleagues from Yale University. The study was published this week in the Journal of the American Medical Association.
There are limited data on the efficacy of red blood cell transfusion in patients undergoing PCI, and what data do exist suggest that receipt of transfusion could be associated with an increased risk of heart attack or death. To better understand both the patterns of transfusion across the country and the risk of adverse outcomes, Sherwood and his colleagues undertook a retrospective cohort study using information from the National Cardiovascular Data Registry (NCDR) CathPCI Registry database. The researchers examined every patient in the database who underwent PCI between July 2009 and March 2013. After excluding patients with missing data or who underwent in-hospital coronary artery bypass graft, they obtained a final study population of 2,258,711 patient visits.
The researchers found that the overall rate of transfusion was 2.14 percent. Patients who underwent transfusion tended to be older and female. They were also more likely to have hypertension, diabetes, advanced kidney dysfunction, and prior heart attack or heart failure. A large majority of sites (96.3 percent) transfused less than 5 percent of the patients studied, while 3.7 percent of sites transfused 5 percent or more of all patients studied.
“There’s a lot of variability in the way physicians transfuse patients, both at the institutional and provider level,” Sherwood said.
The researchers also found that transfusion was associated with an increased risk of heart attack (4.5 percent of patients who received transfusion versus 1.8 percent of patients who did not), stroke (2.0 percent versus 0.2 percent), and in-hospital death (12.5 percent versus 1.2 percent). The increased risk persisted even after the researchers controlled for bleeding complications. These findings, the researchers concluded, suggest that larger, randomized clinical trials are needed to supplement these observational studies to develop evidence-based guidelines for transfusion for ACS patients undergoing PCI.
“We really don’t know which PCI patients would benefit from transfusion and who wouldn’t,” Sherwood said. “We need more data for this population to help clinicians figure out what the best strategies are for their patients.”