To transfuse or not to transfuse

Propensity-matched analysis of association between preoperative anemia and in-hospital mortality in cardiac surgical patients undergoing valvular heart surgeries

Introduction:

Anaemia is associated with increased post-operative morbidity and mortality. We retrospectively assess the relationship between preoperative anaemia and in-hospital mortality in valvular cardiac surgical population.

Materials and Methods:

Data from consecutive adult patients who underwent valvular repair/replacement at our institute from January 2010 to April 2014 were collected from hospital records. Anaemia was defined according to WHO criteria (hemoglobin <13g/dl for males and <12g/dl for females). 1:1 matching was done for anemic and non-anemic patients based on propensity for potentially confounding variables. Logistic regression was used to evaluate the relationship between anaemia and in-hospital mortality. MatchIt package for R software was used for propensity matching and SPSS 16.0.0 was used for statistical analysis.

Results:

2449 patients undergoing valvular surgery with or without coronary artery grafting were included. Anaemia was present in 37.1% (33.91% among males & 40.88% among females). Unadjusted OR for mortality was 1.6 in anemic group (95% Confidence Interval [95% CI] – 1.041-2.570; p=0.033). 1:1 matching was done on the basis of propensity score for anaemia (866 pairs). Balancing was confirmed using standardized differences. Anaemia had an OR of 1.8 for mortality (95% CI- 1.042 to 3.094, P=0.035). Hematocrit of < 20 on bypass was associated with higher mortality.

Conclusion:

Preoperative anaemia is an independent risk factor associated with in-hospital mortality in patients undergoing valvular heart surgery.

Predictors of blood transfusion in patients undergoing coronary artery bypass grafting surgery

OBJECTIVES

The aim of this retrospective study is to identify intraoperative patient's characteristics predicting the need for blood transfusion during CABG in our local cardiac surgical service.

METHODS

This study included 1835 consecutive patients, 1311 males and 524 females with mean age 58.8±9.9 years, undergoing coronary artery bypass grafting. Risk factors detected by univariate study were entered in a multivariate logistic regression model of the relationship between preoperative variables and blood transfusion.

RESULTS

Blood transfusion was used in 435 patients (29.9%). Univariate analysis identified hemoglobin, smoking, hypertension, sex, diabetes, BMI and use of cardiopulmonary bypass (CPB) as significant predictors. Multivariate analysis revealed hemoglobin (OR: 0.8; CI: 0.74-0.86; P<0.001), CPB use (OR: 12.2; CI: 8.2-18.1; P<0.001) and female gender (OR: 2.29; CI:1.72-3.04; P<0.001) as independent risk factors for blood transfusion.

CONCLUSIONS

The predictors of RBC transfusion after isolated CABG were performing CPB, preoperative hemoglobin and female gender. These factors can be used as a clinical tool to preserve blood bank resources without increasing patient's risk.

Is allogeneic blood transfusion a risk factor for sternal dehiscence following cardiac surgery? A prospective observational study

Sternal dehiscence following cardiac surgery has a multifactorial etiology. Significant risk factors contributing to sternal dehiscence include chronic obstructive pulmonary disease (COPD), obesity, or re-exploration due to bleeding or pericardial tamponade. We have focused on the role of allogeneic blood transfusion as a factor leading to the poor healing of surgical wounds. A prospective observational study of 1553 elective and emergency cardiac surgery patients was performed between January 2003 and June 2007. All of the patients enrolled in this study underwent median sternotomy. We studied the relationship between sternal dehiscence following cardiac surgery and the total number of packed red blood cells transfused. The incidence of sternal dehiscence in the study group was 3.4%. Diabetic patients did not have a higher incidence of wound dehiscence. Although COPD, obesity, and re-exploration contributed to sternal dehiscence, the number of allogeneic blood transfusions during the perioperative period was an important independent risk factor for sternal dehiscence. Patients with sternal dehiscence received an average of 7.6 transfusion units (TU) of allogeneic blood versus 1.6 TU of allogeneic blood in the group without sternal dehiscence (P < 0.00005). The dehiscence affected patients without any other significant risk factor who received 6 or more TU, or patients with at least one significant risk factor who received 4 or more TU of allogeneic blood. According to our results, the total amount of allogeneic blood transfused is an important risk factor contributing to sternal dehiscence. Regardless of other risk preconditions, the transfusion of 6 or more TU could result in sternal dehiscence following cardiac surgery.