CHICAGO – Periprocedural blood transfusion rates vary greatly among hospitals performing similar percutaneous interventions for peripheral arterial disease, but these rates can be markedly reduced via a focused quality improvement program.
That’s been the lesson learned in Michigan, where blood transfusion rates dropped by 52% statewide at the 44 hospitals participating in the Blue Cross Blue Shield of Michigan Cardiovascular Consortium Vascular Intervention Collaborative (BMC2 PCI-VIC), Dr. Peter K. Henke reported at the American Heart Association scientific sessions.
That’s good news because periprocedural blood transfusions in patients undergoing percutaneous interventions for peripheral arterial disease (PAD) are associated with startlingly high major morbidity and mortality rates. Indeed, among 18,127 patients undergoing nonhybrid percutaneous interventions for PAD in the BMC2 PCI-VIC registry, periprocedural blood transfusion was an independent predictor of a 25-fold increased risk of MI, a 12.7-fold increase in in-hospital mortality, a 6-fold increased risk of TIA/stroke, and a 49-fold increase in vascular access complications in a logistic regression analysis adjusted for patient demographics, comorbid disease states, and periprocedural medications, according to Dr. Henke, professor of vascular surgery at the University of Michigan, Ann Arbor.
That being said, he was quick to add that he believes these associations largely reflect correlation, not causality. Transfusion recipients were significantly older and sicker than nontransfused patients undergoing the same percutaneous peripheral vascular interventions. They were far more likely to have critical limb ischemia and undergo an urgent or emergent procedure. Of note, as statewide transfusion rates fell from about 6.6% to 3.2% in response to the quality improvement program, crude in-hospital mortality didn’t change significantly, again suggesting a noncausal relationship.
The quality improvement project was undertaken in response to the observation that periprocedural transfusion rates varied institutionally across the state from 0% to 14% for patients undergoing the same percutaneous interventions for PAD. That was a red flag indicating an opportunity for improved practice.
“The median nadir hemoglobin varied within a rather narrow range of 6.8-8.5 g/dL, yet the transfusion rates were quite wide ranging,” the surgeon observed.
Over a 2-year period, the BMC2 PCI-VIC quality improvement team made repeated site visits to the hospitals with the lowest transfusion rates. They performed detailed analysis of peripheral vascular procedure processes, protocols, and order sets in order to identify best practices. Those best practices were then shared at meetings with representatives of all the participating hospitals. Feedback was provided. And transfusion rates began dropping.
Analysis of the 18,000-plus patients enrolled in the registry led to identification of a specific set of risk factors for blood transfusions, most of which occurred after patients had left the catheterization lab. These risk factors included low creatinine clearance, preprocedural anemia, chronic obstructive pulmonary disease, use of warfarin, cerebrovascular disease, critical limb ischemia, and urgent or emergent procedures.
This was the largest-ever study focused on transfusion in patients undergoing endovascular procedures for PAD, according to Dr. Henke. He noted that the results are consistent with a recent report by other investigators regarding the implications of periprocedural blood transfusion in patients undergoing percutaneous coronary intervention. In more than 2.2 million patients who underwent PCI in 2009-2013, transfusion rates varied institutionally from 0% to 13%. Transfusion was associated with 4.6-fold in-hospital mortality, a 3.6-fold increase in acute MI, and a 7.7-fold increased risk of stroke (JAMA 2014;311:836-43).
Dr. Henke reported no financial conflicts of interest regarding the PAD transfusion study, which was funded by Blue Cross Blue Shield of Michigan and the Blue Care Network.