NCDR Data Show Post-PCI Transfusion Linked with Poor Outcomes

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Data from a large US registry of patients who have undergone percutaneous coronary intervention (PCI) demonstrate wide variation in the use of blood transfusions. The study, published in the February 25, 2014, issue of the Journal of the American Medical Association, also found that receiving a transfusion was associated with higher risk of adverse clinical outcomes.

Matthew W. Sherwood, MD, of the Duke Clinical Research Institute (Durham, NC), and colleagues examined transfusion practice patterns and outcomes in 2,258,711 patients from the National Cardiovascular Data Registry (NCDR) CathPCI registry who underwent PCI between July 2009 and March 2013 at 1,431 US hospitals.

Wide Variations in Transfusion Practice

Overall, 2.14% of patients undergoing PCI received a transfusion, with broad variation seen in transfusion patterns across hospitals. While the majority (96.3%) of centers transfused less than 5% of PCI patients, 3.7% of hospitals transfused more than 5% of their patients.

Additionally, more patients who experienced bleeding events—regardless of their postprocedure hemoglobin values—received transfusion compared with those who did not have bleeding.

When hospitals were divided by prevalence of transfusion according to low- (< 1.78%), medium- (1.78% to < 2.79%), and high- (≥ 2.79%) categories, transfusion was more frequent across all postprocedure hemoglobin values (≤ 7 g/dL to ≥ 12 g/dL) at high-transfusing hospitals compared with medium- and low-transfusing hospitals. At high-transfusing hospitals, the threshold for transfusion was between 9 and 10 g/dL, whereas at low-transfusing hospitals, it was between 8 and 9 g/dL.

High-transfusing hospitals were:

• Larger in regards to number of beds and PCI volume
• Less likely to be privately owned or  in rural areas but more likely to be teaching hospitals
• More likely to be located in the New England and Pacific regions
• Less likely to use bivalirudin and more likely to use GPIs

Patients who were transfused were more likely than those who were not to be older, female, hypertensive, diabetic, in advanced renal dysfunction, or to have had prior MI or heart failure.

Variation in hospital risk-standardized rates of transfusion persisted after adjustment, and hospitals showed variability in their transfusion thresholds.

Compared with no transfusion, receiving a transfusion was associated with greater risk of MI, stroke, and in-hospital death, irrespective of bleeding complications (table 1).

Table 1. Association Between Transfusion and Outcome

 
Troubling Lack of Consensus

“These patient-level data, as well as our finding that transfusions were more common across all hemoglobin values at some hospitals, suggest that thresholds for transfusion may have been driven more by local practice patterns than by clinical necessity,” the study authors write.

One explanation, they add, for the variation in transfusion threshold levels may be “previously held beliefs about the benefit of transfusion and recently published data indicating the lack of benefit and potential hazard associated with transfusion.”

Another issue, Dr. Sherwood and colleagues point out, is that there is little randomized clinical trial evidence for transfusion practices and none for the broad population of patients undergoing PCI. This lack of consensus is reflected in the American Association of Blood Banks’ 2012 guidelines, which make no recommendations regarding transfusion strategies in ACS patients. The guidelines suggest limiting transfusion to those with either symptomatic anemia or a hemoglobin level of 8mg/dL or lower.

The study authors note some limitations of the study. For instance, even though the CathPCI registry captures data from most US cath labs, it does not include every hospital and thus may not fully represent practice nationwide. Moreover, the registry does not contain information on physicians other than the interventional cardiologist who performed the procedure, and so may not capture variations among individual practitioners.

Investigation of Transfusion Threshold Needed

In an email with TCTMD, Gregg W. Stone, MD, of Columbia University Medical Center (New York, NY), said the study “nicely highlights” the variation in transfusion thresholds and practices across the United States.

“Like many prior observational studies, it re-emphasizes the strong link between transfusions and adverse short-term outcomes,” he said, adding that a large-scale randomized trial is needed to sort out the appropriate threshold for transfusion after PCI in patients with and without overt bleeding complications.

“Pending the results from these trials, along with a restrictive transfusion policy, use of bleeding avoidance strategies would seem to be prudent, and in this regard it is interesting to note that greater use of bivalirudin and less use of GPIs were associated with fewer transfusions, consistent with the results from numerous randomized trials,” Dr. Stone observed.

Dr. Sherwood and colleagues agreed that “[until randomized trials on transfusion] have been completed, operators should use strategies that reduce the risk of bleeding and subsequent transfusion.”

 

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Source:
Sherwood MW, Wang Y, Curtis JP, et al. Patterns and outcomes of red blood cell transfusion in patients undergoing percutaneous coronary intervention. JAMA. 2014;311(8):836-843.

 

• Dr. Stone reports serving as a consultant to Boston Scientific.

 

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