Patterns and Outcomes of Red Blood Cell Transfusion in Patients Undergoing Percutaneous Coronary Intervention

Study Questions:

What are the current patterns and implications of blood transfusion among patients undergoing percutaneous coronary intervention (PCI) across hospitals in the United States?

Methods:

The authors performed a retrospective cohort study of all PCI procedures from the CathPCI Registry from July 2009 to March 2013. The primary outcomes were the transfusion rates in the overall population and by hospital. The association of transfusion with myocardial infarction, stroke, and death was assessed after accounting for a patient’s propensity for transfusion.

Results:

The overall rate of transfusion was 2.14% and slightly declined from 2.11% in the first quarter to 2.04% in the last study quarter. Patients who were more likely to receive transfusion were older, more likely to be women (56.3% vs. 32.5%), and had hypertension (86.4% vs. 82.0%), diabetes (44.8% vs. 34.6%), advanced renal dysfunction (8.7% vs. 2.3%), prior myocardial infarction (33.0% vs. 30.2%), or prior heart failure (27.0% vs. 11.8%). Overall, at 96.3% of sites, transfusion was administered to <5% of the patients while at 3.7% of sites, it was provided to over 5% of the patients. There was considerable variation in hospital risk-standardized rates of transfusion that persisted after adjustment for baseline patient differences. Transfusion was associated with myocardial infarction (4.5% vs. 1.8%; odds ratio [OR], 2.60; 95% confidence interval [CI], 2.57-2.63), stroke (2.0% vs. 0.2%; OR, 7.72; 95% CI, 7.47-7.98), and in-hospital death (12.5% vs. 1.2%; OR, 4.63; 95% CI, 4.57-4.69).

Conclusions:

The authors concluded that there is considerable variation in blood transfusion for patients undergoing PCI at US hospitals, and receipt of transfusion was associated with increased risk of in-hospital adverse cardiac events.

Perspective:

This study highlights the significant variation in transfusion practice after PCI across different institutions. Although the causal versus casual nature of adverse events after transfusion can be debated, this variation suggests that transfusion may be overused in certain cases and there may be potential to reduce its use without impacting clinical outcomes. The appropriate threshold for transfusion in this patient cohort is unknown, and a large pragmatic clinical trial is needed to guide practice in this field.

Keywords: Registries, Myocardial Infarction, Stroke, Erythrocyte Transfusion, Heart Failure, Hypertension, Diabetes Mellitus, United States, Percutaneous Coronary Intervention


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