Elsevier

The Annals of Thoracic Surgery

Volume 96, Issue 5, November 2013, Pages 1628-1634
The Annals of Thoracic Surgery

Original article
Adult cardiac
Preoperative Hematocrit Is a Powerful Predictor of Adverse Outcomes in Coronary Artery Bypass Graft Surgery: A Report From The Society of Thoracic Surgeons Adult Cardiac Surgery Database

Presented at the Forty-ninth Annual Meeting of The Society of Thoracic Surgeons, Los Angeles, CA, Jan 26–30, 2013.
https://doi.org/10.1016/j.athoracsur.2013.06.030Get rights and content

Background

Small series have identified a relationship between preoperative hematocrit (HCT) and outcomes in coronary artery bypass graft (CABG) surgery. The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (ACSD) began collecting preoperative HCT data in 2008. In this study, analyses were performed to determine the impact of preoperative HCT on perioperative morbidity and mortality among patients undergoing isolated CABG.

Methods

Data were collected on 182,599 patients who underwent primary isolated on-pump CABG between 2008 and 2009 and were included in the STS ACSD. Data were included only from centers that performed more than 100 on-pump cases per year during the period of study. Dialysis patients as well as those with previous cardiovascular operations or missing data for HCT were excluded. We then performed multivariable analysis using the 2008 STS CABG risk model as a guide, including HCT as a predictor. Logistic regression was performed for operative mortality and other adverse outcomes.

Results

Overall operative mortality was 1.6% (3,005 of 182,599). Compared with patients with anemia (HCT <33%), patients with HCT of at least 42% had lower mortality (1.1% versus 3.4%; p < 0.0001) and lower rates of renal failure (2.0% versus 7.8%; p < 0.0001), stroke (0.9% versus 1.8%; p < 0.0001), prolonged ventilation (8.4% versus 17.5%; p < 0.0001), and deep sternal wound infection (0.3% versus 0.6%; p < 0.0001). In adjusted analyses, each 5-point decrease in preoperative HCT was associated with an 8% higher odds of death (odds ratio, 1.08; p = 0.0003), a 22% increase in the odds of postoperative renal failure (odds ratio, 1.22; p < 0.0001), and a 10% increase in the risk of deep sternal wound infection (odds ratio, 1.10; p < 0.01). Similar results were observed among patients (n = 74,292) undergoing elective CABG. The percentage of patients receiving perioperative blood transfusion decreased from 88.5% in the anemic group (HCT <33%) to 32.5% in patients with HCT of at least 42% (p < 0.0001).

Conclusions

Preoperative HCT is a powerful independent predictor of perioperative mortality as well as renal failure and deep sternal wound infection in patients undergoing isolated primary CABG operations. These findings should prompt investigation of strategies to increase preoperative HCT.

Section snippets

The Society of Thoracic Surgeons Adult Cardiac Surgery Database

The STS ACSD was established in 1989 to report surgical outcomes after cardiothoracic surgical procedures [16]. Patient data are entered from sites using uniform definitions (available online at http://www.sts.org) and certified software systems. Although participation in the STS database is voluntary, data completeness is high, with overall preoperative risk factors missing in fewer than 5% of submitted cases. The STS ACSD currently includes data from more than 90% of hospitals performing

Results

We identified 182,599 patients who underwent primary isolated on-pump CABG between January 2008 and December 2009. Patient characteristics are outlined in Table 1. The median age was 65 years, 27% were women, and the mean ejection fraction was 0.513. The median preoperative HCT was 39% (interquartile range, 36% to 42%). The distribution of preoperative HCT is illustrated in Fig 1. The preoperative HCT was less than or equal to 36% in 30.1% (54,948 of 182,599) of patients and was less than 39%

Comment

The key findings of this study include the following: (1) among a contemporary national experience of more than 180,000 patients undergoing primary isolated CABG, the preoperative HCT is a powerful independent predictor of mortality, renal failure, deep sternal wound infection, and prolonged hospital stay; (2) of all the morbidity and mortality outcomes examined in this study, the preoperative HCT has the greatest and most consistent impact on the risk of renal failure; (3) similar outcomes

References (27)

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