Original article
Adult cardiac
The Impact of Blood Conservation on Outcomes in Cardiac Surgery: Is It Safe and Effective?

https://doi.org/10.1016/j.athoracsur.2010.04.089Get rights and content

Background

Increasing evidence shows that perioperative blood transfusion in cardiac surgery is associated with increased postoperative morbidity and mortality and decreased long-term survival. Tolerance of “permissive anemia” is an important element of perioperative blood conservation strategy. The safety of tolerating perioperative anemia has been a significant deterrent for widespread application of blood conservation. This study examines whether blood conservation is equally safe or superior to the common practice of transfusion in cardiac surgery.

Methods

The total study population consisted of 32,449 patients who underwent isolated coronary artery bypass surgery from June 2000 until December 2004 with complete data from 17 institutions in the State of New Jersey. Englewood Hospital and Medical Center (EH) has a well-established blood conservation program. Five hundred eighty-six EH patients (blood conservation cohort) were compared with a propensity score–matched cohort of 586 patients from the other New Jersey institutions (OH-M) representing the common practice of transfusion. Outcomes were classified as very serious complications, serious complications, or neither (no very serious complication or serious complication). Analysis consisted of McNemar tests and multiple logistic regression.

Results

Fewer patients were transfused at EH compared with OH-M (10.6% versus 42.5%; p < 0.0001). Englewood Hospital had 5 (0.8%) deaths versus 15 (2.5%) in the OH-M group (p = 0.02). Of the EH patients, 11.1% experienced a very serious complication or serious complication versus 18.7% in the OH-M cohort (p = 0.0002). Transfusion was associated with an increased risk of an adverse outcome in both cohorts (EH: odds ratio, 7.3; 95% confidence interval, 3.7 to 14.4 versus OH-M: odds ratio, 4.6; 95% confidence interval, 2.8 to 7.7).

Conclusions

Blood conservation is safe and effective in reducing transfusions. Tolerance of perioperative anemia, which is one of the main components of blood conservation, does not increase the risk of complications or death in cardiac surgery. Avoidance of transfusion reduces the risk of complications. This study further solidifies the relationship between transfusion and adverse outcome in cardiac surgery.

Section snippets

Material and Methods

Since its inception in 2000 the cardiac surgery program at Englewood Hospital and Medical Center has a well-established blood conservation protocol. The program was started as part of the “Blood Conservation Demonstration Project” under the auspices of the New Jersey State Department of Health and Senior Services (NJDHSS) certificate of need (NJAC 8:33-3.11). The goal of the project was to implement blood conservation in cardiac surgery and report on its safety and efficacy. The techniques and

Results

The total study population consisted of 32,449 patients who underwent isolated CABG surgery from June 2000 until December 2004 with complete data from 17 institutions. There were 31,863 patients from the OH and 586 were from EH. From the pool of patients in the OH group, a match was selected for each OH patient on the basis of the closest propensity score. Five hundred eighty-six matched patients were selected to form the OH-M cohort (Table 2). Patient demographics and risk factors for the EH

Comment

There is large variability in transfusion rates among cardiac surgery centers. On average 50% to 60% of patients undergoing cardiac surgery receive blood transfusions and about 20% of the nation's blood supply is used in cardiac surgery [33]. Guidelines for blood transfusions in patients without known risk factors suggest a transfusion trigger in the range of 6 to 10 g/dL [17]. Cardiac surgical patients represent a particularly vulnerable population that may be adversely affected by anemia

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