Effects of red blood cell transfusion on patients undergoing cardiac surgery in Queensland - a retrospective cohort study

BACKGROUND

Packed red blood cell (pRBC) transfusion is a relatively safe and mainstay treatment commonly used in cardiac surgical patients. However, there is limited evidence on clinical effects of transfusing blood nearing end-of shelf life that has undergone biochemical changes during storage.

OBJECTIVE

To investigate evidence of associations between morbidity/mortality and transfusion of blood near end of shelf-life (> 35 days) in cardiac surgical patients.

METHODS

Data from the Queensland Health Admitted Patient Data Collection database 2007-2013 was retrospectively analysed. Coronary artery bypass graft and valvular repair patients were included. Multivariable logistic regression was used to examine the effect of pRBC age (< 35 days vs. ≥ 35 days) on in-hospital mortality and morbidity. As secondary analysis, outcomes associated with the number of pRBC units transfused (≤ 4 units vs. ≥ 5 units) were also assessed.

RESULTS

A total of 4514 cardiac surgery patients received pRBC transfusion. Of these, 292 (6.5%) received pRBCs ≥ 35 days. No difference in in-hospital mortality or frequency of complications was observed. Transfusion of ≥ 5 units of pRBCs compared to the ≤ 4 units was associated with higher rates of in-hospital mortality (5.6% vs. 1.3%), acute renal failure (17.6% vs. 8%), infection (10% vs. 3.4%), and acute myocardial infarction (9.2% vs. 4.3%). Infection carried an odds ratio of 1.37 between groups (CI = 0.9-2.09; p = 0.14) and stroke/neurological complications, 1.59 (CI = 0.96-2.63; p = 0.07).

CONCLUSION

In cardiac surgery patients, transfusion of pRBCs closer to end of shelf-life was not shown to be associated with significantly increased mortality or morbidity. Dose-dependent differences in adverse outcomes (particularly where units transfused were > 4) were supported.

Antifibrinolytics and cardiac surgery: The past, the present, and the future

Cardiac surgery is usually associated with significant blood loss, which often necessitates blood transfusion. In order to decrease the risks associated with the latter, pharmacological as well as nonpharmacological strategies have been used to reduce blood loss. Among the pharmacological approaches, antifibrinolytic drugs are the mainstay. Aprotinin, which was the first ubiquitously used drug, fell into disrepute only to re-emerge after much debate. The decline of aprotinin paved the way for the lysine analogs. However, we must be aware with the side effects of these drugs as well as the dose modification required in special situations. Nonsaccharide glycosaminoglycans have been under investigation to overcome the drawbacks of the lysine analogs. It remains to be seen whether these drugs can replace the traditional antifibrinolytics.

Pharmacological management of perioperative bleeding in cardiac surgery

[first paragraph of article]In spite of the growing discoveries in cardiac surgery, perioperative bleeding remains one of the most common causes of morbidity and mortality. Around 50-60% of cardiac surgery patients receive blood transfusions, which are harmful and strongly associated with increased morbidity, mortality, hospital stay, and hospital cost. Patients taken back to the OR for re-exploration and control of bleeding after cardiac surgery, have a four-fold increase in the incidence of sternal infection and mortality.

Multicentre randomized clinical trial to investigate the cost-effectiveness of an allogeneic single-donor fibrin sealant after coronary artery bypass grafting (FIBER Study)

BACKGROUND

Reduction of blood transfusion in cardiac surgery is an important target. The aim of this study was to investigate the cost-effectiveness of the use of CryoSeal®, an allogeneic single-donor fibrin sealant, in patients undergoing coronary artery bypass grafting (CABG).

METHODS

This randomized clinical study involved seven cardiac surgery centres in the Netherlands. Patients undergoing elective isolated CABG with the use of at least one internal thoracic artery (ITA) graft were assigned randomly to receive either CryoSeal® (5 ml per ITA bed) or no CryoSeal®. Primary efficacy endpoints were units of transfused red blood cells, fresh frozen plasma and platelet concentrates, and duration of intensive care unit stay. Secondary efficacy endpoints were 48-h blood loss, reoperation for bleeding, mediastinitis, 30-day mortality and duration of hospital stay.

RESULTS

Between March 2009 and January 2012, 1445 patients were randomized. The intention-to-treat (ITT) population comprised 1436 patients; the per-protocol (PP) population 1292. In both the ITT and the PP analysis, no significant difference between the treatment groups was observed for any of the primary and secondary efficacy endpoints. In addition, no significant difference between the groups was seen in the proportion of transfused patients. Estimated CryoSeal® costs were €822 (95 per cent c.i. €808 to €836) per patient, which translated to €72,000 per avoided transfusion (unbounded 95 per cent c.i.).

CONCLUSION

The use of the fibrin sealant CryoSeal® did not result in health benefits. Combined with the high cost per avoided transfusion, this study does not support the implementation of routine CryoSeal® use in elective isolated CABG.

REGISTRATION NUMBER

NTR1386 ( http://www.trialregister.nl).

Transfusion practice varies widely in cardiac surgery: Results from a national registry

OBJECTIVES

Evidence is accumulating of adverse outcomes associated with transfusion of blood components. If there are differences in perioperative transfusion rates in cardiac surgery, and what hospital factors may contribute, requires further investigation.

METHODS

Analysis of 42,743 adult patients who underwent 43,482 procedures from 2005 to 2011 at 25 Australian hospitals, according to the Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database. Multiple logistic regression examined associations of patient and hospital characteristics with transfusion of ≥1 red blood cell (RBC) unit; platelet (PLT), fresh frozen plasma (FFP), and cryoprecipitate (CRYO) doses; and ≥5 RBC units, from surgery until hospital discharge.

RESULTS

Procedures included 24,222 (55%) isolated coronary artery bypass grafts, 7299 (17%) isolated valve, 4714 (11%) coronary artery bypass graft and valve, and 7247 (17%) other procedures. After adjustment for various patient and procedure characteristics, transfusion rates varied across hospitals for ≥1 RBC unit from 22% to 67%, ≥5 RBC units from 5% to 25%, ≥1 PLT dose from 11% to 39%, ≥1 FFP dose from 11% to 48% and ≥1 CRYO dose from 1% to 20%. Hospital characteristics, including state or territory, private versus public, and teaching versus nonteaching, were not associated with variation in transfusion rates.

CONCLUSIONS

Variation in transfusion of all components and large volume RBC was identified, even after adjustment for patient and procedural factors known to influence transfusion, and this was not explained by hospital characteristics.

Patient blood management - a new paradigm for transfusion medicine?

The saving of many lives in history has been duly credited to blood transfusions. What is frequently overlooked is the fact that, in light of a wealth of evidence as well as other management options, a therapy deemed suitable yesterday may no longer be the first choice today. Use of blood has not been based upon scientific evaluation of benefits, but mostly on anecdotal experience and a variety of factors are challenging current practice. Blood is a precious resource with an ever limiting supply due to the aging population. Costs have also continually increased due to advances (and complexities) in collection, testing, processing and administration of transfusion, which could make up 5% of the total health service budget. Risks of transfusions remain a major concern, with advances in blood screening and processing shifting the profile from infectious to non‐infectious risks. Most worrying though, is the accumulating literature demonstrating a strong (often dose‐dependent) association between transfusion and adverse outcomes. These include increased length of stay, postoperative infection, morbidity and mortality. To this end, a recent international consensus conference on transfusion outcomes (ICCTO) concluded that there was little evidence to corroborate that blood would improve patients’ outcomes in the vast majority of clinical scenarios in which transfusions are currently routinely considered; more appropriate clinical management options should be adopted and transfusion avoided wherever possible. On the other hand, there are patients for whom the perceived benefits of transfusion are likely to outweigh the potential risks. Consensus guidelines for blood component therapy have been developed to assist clinicians in identifying these patients and most of these guidelines have long advocated more conservative ‘triggers’ for transfusion. However, significant variation in practice and inappropriate transfusions are still prevalent. The ‘blood must always be good philosophy’ continues to permeate clinical practice. An alternative approach, however, is being adopted in an increasing number of centres. Experience in managing Jehovah’s Witness patients has shown that complex care without transfusion is possible and results are comparable with, if not better than those of transfused patients. These experiences and rising awareness of downsides of transfusion helped create what has become known as ‘patient blood management’. Principles of this approach include optimizing erythropoiesis, reducing surgical blood loss and harnessing the patient’s physiological tolerance of anaemia. Treatment is tailored to the individual patient, using a multidisciplinary team approach and employing a combination of modalities. Results have demonstrated reduction of transfusion, improved patient outcomes and patient satisfaction. Significant healthcare cost savings have also followed. Despite the success of patient blood management programmes and calls for practice change, the potential and actual harm to patients caused through inappropriate transfusion is still not sufficiently tangible for the public and many clinicians. This has to change. The medical, ethical, legal and economic evidence cannot be ignored. Patient blood management needs to be implemented as the standard of care for all patients.

The effect of aprotinin on risk of acute renal failure requiring dialysis after on-pump cardiac surgery

The use of aprotinin in cardiac surgery to reduce perioperative bleeding and transfusion is controversial. We assessed the effect of aprotinin on the risk of acute renal failure in 423 patients who underwent on-pump cardiac surgery between January 1, 2005 and December 31, 2006. Of these 423 patients, 318 (75.2%) received aprotinin (median dose=3.0 million KIU, standard deviation=2.8 million KIU; interquartile range: 2 million KIU to 4 million KIU). Aprotinin was more likely to be used in patients who did not cease aspirin before surgery, in urgent or emergency surgery, who had impaired left ventricular function, a longer period of bypass and aortic cross-clamp time, and with both coronary artery bypass graft and valvular surgery performed. The overall incidence of acute renal failure requiring dialysis was 2.8%. The use of aprotinin was not associated with a reduction in transfusion nor an increased risk of renal failure requiring dialysis, atrial fibrillation, cerebrovascular accident or mortality in the univarate analyses. In the multivariate analysis, only preoperative serum creatinine concentration (odds ratio [OR] 1.06 per 10 micromol/l increment in creatinine, 95% confidence interval [CI]: 1.01 to 1.14, P=0.029) and urgency of the surgery (urgent vs. scheduled surgery: OR 12.8, CI: 2.3 to 70.8, P=0.004; emergency vs. scheduled surgery: OR 23.1, CI: 3.0 to 180.2, P=0.003) were significantly associated with an increased risk of acute renal failure requiring dialysis. The use of low-dose aprotinin did not significantly reduce perioperative transfusion requirements and was not a significant risk factor for acute renal failure requiring dialysis in our patients.