Limited Blood Transfusion Does Not Impact Survival in Octogenarians Undergoing Cardiac Operations

Blood Transfusion in Elderly Patients with Acute Myocardial Infarction: Data from the RICO Survey

BACKGROUND

Red blood cell transfusion benefit during acute myocardial infarction remains unclear in the elderly. We aimed to assess the transfusion impact on 1-year mortality in acute myocardial infarction patients aged ≥65 years, according to their age and hemoglobin nadir.

METHODS

We included 3316 consecutive patients with acute myocardial infarction aged ≥65 years from the "obseRvatoire des Infarctus de Côte d'Or" (RICO) survey. They were categorized according to their hemoglobin nadir (≤8, >8 to ≤10, and >10 g/dL) and age (<80 or ≥80 years).

RESULTS

A total of 1906 patients (57%) were 65-79 years old, and 1410 (43%) were aged ≥80 years, of whom 103 (5%) and 145 (10%) patients received red blood cell transfusion, respectively (P < .001). In Cox regression analysis, transfusion was associated with increased 1-year mortality for hemoglobin nadir >10 g/dL but no significant effect for hemoglobin nadir between 8 and 10 g/dL. When hemoglobin nadir was ≤8 g/dL, transfusion did not influence 1-year mortality for younger patients (65-79 years). However, for older patients (≥80 years), transfusion was associated with lower mortality (hazard ratio 0.43 [95% confidence interval, 0.22-0.86], P = .016).

CONCLUSION

Among older patients with acute myocardial infarction, the effect of transfusion was largely dependent on hemoglobin threshold and age. Transfusion was associated with increased 1-year mortality when hemoglobin nadir was >10 g/dL. However, in patients aged ≥80 years with hemoglobin nadir <8 g/dL, transfusion was associated with a 50% reduction in 1-year mortality.

Age and blood transfusion: relationship and prognostic implications in cardiac surgery

Background

Red blood cell (RBC) transfusion is a well-known predictor of acute kidney injury (AKI) and death after cardiac surgery. This study aimed to define the relationship between age and the need for RBC.

Methods

Study population included 1,765 consecutive patients undergoing on-pump procedures from 2013 to 2015. The relationship between RBC transfusion and both survival and AKI, and any interaction with age was estimated. A propensity score for the likelihood to receive RBC transfusion was calculated using multivariate logistic regression analysis to adjust for the effect of confounding factors. A logistic estimation curve was developed to investigate the interaction between this score and age.

Results

Patients receiving RBC transfusions had more comorbidities irrespective of age. Elderly patients underwent transfusion more often than younger patients with a 1.3-fold increase in the relative risk for transfusion. Age did not independently predict the need for RBC. AKI and mortality rates were significantly higher in transfused subsets irrespective of age.

Conclusions

Comorbidity profile and not age per se confers an increased risk of transfusion.

The Effect of Blood Transfusion on Outcomes in Aortic Surgery

The use of blood transfusion in cardiac surgery varies widely. The beneficial effects of blood products are offset by an increase in morbidity and mortality. Despite multiple studies showing an association between blood product exposure and adverse short- and long-term events, it is difficult to determine causality. Nevertheless, the implication is sufficient to warrant the search for alternative strategies to reduce the use of blood products while providing a standard of care that optimizes postoperative outcomes. Aortic surgery, in particular, is associated with an increased risk of bleeding requiring a blood transfusion. There is a paucity of evidence within aortic surgery regarding the deleterious effects of blood products. Here, we review the current evidence regarding patient outcomes after blood transfusion in cardiac surgery, with special emphasis on aortic surgery.

The impact of minor blood transfusion on the outcome after coronary artery bypass grafting

PURPOSE

To investigate the impact of minor perioperative bleeding requiring transfusion of 1-2 red blood cell (RBC) units on the outcome after coronary artery bypass grafting (CABG).

METHODS

Sixteen cardiac surgical centers contributed to the prospective European CABG registry (E-CABG). 1014 patients receiving 1-2 RBC units during or after isolated CABG were compared to 2264 patients not receiving RBCs.

RESULTS

In 827 propensity score matched pairs, transfusion of 1-2 RBC units did not affect the risk of in-hospital/30-day death (p=0.523) or stroke (p=0.804). However, RBC transfusion was associated with an increased risk of acute kidney injury (p=0.008), sternal wound infection (p=0.001), postoperative use of antibiotics (p=0.001), prolonged use of inotropes (p<0.0001), use of intra-aortic balloon pump (p=0.012), length of intensive care unit stay (p<0.0001) and length of in-hospital stay (p<0.0001). Matched paired analysis excluding pre- and postoperative critical hemodynamic conditions showed that RBC transfusion was associated with an increased risk of major complications except in-hospital/30-day death.

CONCLUSION

Minor perioperative bleeding and subsequent transfusion of 1-2 RBC units did not affect the risk of early death, but increased the risk of other major adverse events. Minimizing perioperative bleeding and prevention of even low-volume RBC transfusion may improve the outcome after CABG.

Balancing the benefits and risks of blood transfusions in patients undergoing cardiac surgery: a propensity-matched analysis

OBJECTIVES

Prior studies have found that cardiac surgery patients receiving blood transfusions are at risk for increased mortality and morbidity following surgery. It is not clear whether this increased risk occurs across all haematocrit (HCT) levels. The goal of this study was to compare operative mortality in propensity-matched cardiac surgery patients based on stratification of the preoperative HCT levels.

METHODS

Between 1 August 2004 and 30 June 2011, 3516 patients had cardiac surgery. One thousand nine hundred and twenty-two (54.5%) required blood transfusion during or after surgery. A propensity score for transfusion was developed based on 22 baseline variables. One thousand seven hundred and fourteen patients were matched: 857 in the transfusion group (TG) and 857 in the non-transfused control group (CG). Univariate analyses demonstrated that, after propensity matching, the groups did not differ on any baseline factors included in the propensity model. Operative mortality was defined as death within 30 days of surgery. Preoperative HCT was stratified into four groups: <36, 36-39, 40-42 and ≥ 43.

RESULTS

For HCT <36%, 30-day mortality was higher in the TG than that in the CG (3.0 vs 0.0%). For HCT 36-39, operative mortality was similar between TG (1.1%, N = 180) and CG (0.8%, N = 361; P = 0.748). For HCT 40-42, operative mortality was significantly higher in the TG compared with that in the CG (1.9 vs 0%, N = 108 and 218, respectively; P = 0.044). For HCT of ≥ 43, there was a trend towards higher operative mortality in the TG vs the CG (2.0 vs 0%, N = 102 and 152, respectively; P = 0.083). Other surgical complications followed the same pattern with higher rates found in the transfused group at higher presurgery HCT levels. HCT at discharge for the eight groups were similar, with an average of 29.1 ± 1.1% (P = 0.117).

CONCLUSIONS

Our study indicates that a broad application of blood products shows no discernible benefits. Furthermore, patients who receive blood at all HCT levels may be placed at an increased risk of operative mortality and/or other surgical complications. Paradoxically, even though patients with low HCTs theoretically should benefit the most, transfusion was still associated with a higher complication and mortality rate in these patients. Our results indicate that blood transfusion should be used judiciously in cardiac surgery patients.

Is single-unit blood transfusion bad post-coronary artery bypass surgery?

OBJECTIVES

Publications in the surgical literature are very consistent in their conclusions that blood is dangerous with regard to in-hospital mortality, morbidity and long-term survival. Blood is frequently used as a volume expander while simultaneously increasing the haematocrit. We investigated the effects of a single-unit blood transfusion on long-term survival post-cardiac surgery in isolated coronary artery bypass grafting patients.

METHODS

A prospective single-institution cardiac surgery database was analysed involving 4615 patients. Univariate, multivariate stepwise Cox regression analysis and propensity matching were performed to identify whether a single-unit blood transfusion was detrimental to long-term survival.

RESULTS

Univariate analysis revealed that blood was significantly associated with a reduced long-term survival even with a single-unit transfused, P = 0.0001. Cox multivariate regression analysis identified age, ejection fraction, preoperative dialysis, logistic EuroSCORE, postoperative CKMB, blood transfusion, urgent operative status and atrial fibrillation as significant factors determining long-term survival. When the Cox regression was repeated with patients who received no blood or only one unit of blood, transfusion was not a risk factor for long-term survival. An interaction analysis revealed that blood transfusion was significantly interacting with preoperative haemoglobin levels, P = 0.02. Propensity analysis demonstrated that a single-unit transfusion is not associated with a detrimental long-term survival, P = 0.3.

CONCLUSIONS

Cox regression and propensity matching both indicate that a single-unit transfusion is not a significant cause of reduced long-term survival. Preoperative anaemia is a significant confounding factor. Despite demonstrating the negligible risks of a single-unit blood transfusion, we are not advocating liberal transfusion and would recommend changing from a double-unit to a single-unit transfusion policy. We speculate that blood is not bad, but that the underlying reason that it is given might be.