Transfusion of Blood Products Affects Outcome in Cardiac Surgery

Predictors of length of hospital stay after pediatric Ebstein anomaly corrective surgery: a retrospective cohort study

BACKGROUND

The remarkable advancements in surgical techniques over recent years have shifted the clinical focus from merely reducing mortality to enhancing the quality of postoperative recovery. The duration of a patient's hospital stay serves as a crucial indicator in evaluating postoperative recovery and surgical outcomes. This study aims to identify predictors of the length of hospital stay for children who have undergone corrective surgery for Ebstein Anomaly (EA).

METHODS

We conducted a retrospective cohort study on children (under 18 years of age) diagnosed with EA who were admitted for corrective surgery between January 2009 and November 2021 at Fuwai Hospital. The primary outcome was the Time to Hospital Discharge (THD). Cox proportional hazard models were utilized to identify predictors of THD. In the context of time-to-event analysis, discharge was considered an event. In cases where death occurred before discharge, it was defined as an extended THD, input as 100 days (exceeding the longest observed THD), and considered as a non-event.

RESULTS

A total of 270 children were included in this study, out of which three died in the hospital. Following the Cox proportional hazard analysis, six predictors of THD were identified. The hazard ratios and corresponding 95% confidence intervals were as follows: age, 1.030(1.005,1.055); C/R > 0.65, 0.507(0.364,0.707); Carpentier type C or D, 0.578(0.429,0.779); CPB time, 0.995(0.991,0.998); dexamethasone, 1.373(1.051,1.795); and transfusion, 0.680(0.529,0.875). The children were categorized into three groups based on the quartile of THD. Compared to children in the ≤ 6 days group, those in the ≥ 11 days group were associated with a higher incidence of adverse outcomes. Additionally, the duration of mechanical ventilation and ICU stay, as well as hospital costs, were significantly higher in this group.

CONCLUSION

We identified six predictors of THD for children undergoing corrective surgery for EA. Clinicians can utilize these variables to optimize perioperative management strategies, reduce adverse complications, improve postoperative recovery, and reduce unnecessary medical expenses.

Blood transfusion in elective total hip arthroplasty: can patient-specific parameters predict transfusion?

Aims

Transfusion after primary total hip arthroplasty (THA) has become rare, and identification of causative factors allows preventive measures. The aim of this study was to determine patient-specific factors that increase the risk of needing a blood transfusion.

Methods

All patients who underwent elective THA were analyzed retrospectively in this single-centre study from 2020 to 2021. A total of 2,892 patients were included. Transfusion-related parameters were evaluated. A multiple logistic regression was performed to determine whether age, BMI, American Society of Anesthesiologists (ASA) grade, sex, or preoperative haemoglobin (Hb) could predict the need for transfusion within the examined patient population.

Results

The overall transfusion rate was 1.2%. Compared to the group of patients without blood transfusion, the transfused group was on average older (aged 73.8 years (SD 9.7) vs 68.6 years (SD 10.1); p = 0.020) and was mostly female (p = 0.003), but showed no significant differences in terms of BMI (28.3 kg/m2 (SD 5.9) vs 28.7 kg/m2 (SD 5.2); p = 0.720) or ASA grade (2.2 (SD 0.5) vs 2.1 (SD 0.4); p = 0.378). The regression model identified a cutoff Hb level of < 7.6 mmol/l (< 12.2 g/dl), aged > 73 years, and a BMI of 35.4 kg/m² or higher as the three most reliable predictors associated with postoperative transfusion in THA.

Conclusion

The possibility of transfusion is predictable based on preoperatively available parameters. The proposed thresholds for preoperative Hb level, age, and BMI can help identify patients and take preventive measures if necessary.

Impact of intra- and extramedullary alignment on blood loss in total knee arthroplasty: a retrospective study

BACKGROUND

There is a scarcity of scientific data regarding the correlation between alignment techniques during total knee arthroplasty (TKA) and blood loss as well as transfusion rates. This study's hypothesis posited that intramedullary-aligned (IM) TKA exhibits higher blood loss and transfusion rates when contrasted with extramedullary-aligned (EM) TKA.

METHODS

We conducted a retrospective examination of 883 patients who underwent total knee arthroplasty (TKA) in 2021 at a solitary orthopedic center in Germany. These patients were divided into two groups based on their tibial alignment technique: extramedullary alignment and intramedullary tibial alignment.

RESULTS

In the intramedullary tibial alignment (IM) group, we observed a blood loss of 0.91 L, while in the extramedullary tibial alignment (EM) group, the blood loss was 0.89 L. These values did not demonstrate a significant difference (p = 0.69). Transfusion rates were 0.99% in the IM group and 0.21% in the EM group, and there was no significant distinction between them (Chi-squared test: p > 0.05).

CONCLUSION

We observed no statistically significant variance in blood loss between the IM and EM groups. Likewise, there was no substantial disparity in transfusion rates between these groups. It can be concluded that the selection of a knee arthroplasty system incorporating either intramedullary tibial alignment or extramedullary alignment does not significantly impact blood loss.

Cemented and hybrid total hip arthroplasty lead to lower blood loss in primary total hip arthroplasty: a retrospective study

BACKGROUND

Little scientific evidence exists on blood loss and transfusion rates depending on the fixation technique. The hypothesis of this study was that the blood loss and transfusion rate are lower in cemented and hybrid total hip arthroplasty (THA) compared to cementless THA.

METHODS

We retrospectively compared a total of 1500 patients who received either cementless, cemented, hybrid or reverse hybrid THA. All patients underwent THA in 2021 at a single orthopedic center in Germany.

RESULTS

The lowest blood loss was found in patients who received a fully cemented THA (695 ± 74 ml). Hybrid THA with a cemented stem showed a blood loss of 845 ± 30 ml and reverse hybrid THA showed the highest blood loss with an average of 994 ± 74 ml. Cementless THA caused an average blood loss of 957 ± 16 ml. There was a significant difference between cementless THA, hybrid THA (cemented stem), and fully cemented THA (p < 0.05). Transfusion rates ranged from 1.3% (cementless THA) to 7.9% (cemented THA) between the groups with a transfusion rate of 2.5% overall.

CONCLUSION

We found significantly lower blood loss in cemented THA and hybrid THA compared to cementless THA. Although blood loss was lower in cemented and hybrid THA, this did not result in lower transfusion rates. This could be due to other confounders such as age, comorbidities, and preoperative anemia.

Prolonged mechanical ventilation after lung transplantation: risks factors and consequences on recipient outcome

Background

Risk factors and the incidence of prolonged mechanical ventilation (PMV) after lung transplantation (LT) have been poorly described. The study assessed predictive factors of PMV after LT.

Methods

This observational, retrospective, monocentric study included all patients who received LT in Bichat Claude Bernard Hospital between January 2016 and December 2020. PMV was defined as a duration of MV > 14 days. Independent risk factors for PMV were studied using multivariate analysis. One-year survival depending on PMV was studied using Kaplan Meier and log-rank tests. A p value <0.05 was defined as significant.

Results

224 LT recipients were analysed. 64 (28%) of them received PMV for a median duration of 34 [26-52] days versus 2 [1-3] days without PMV. Independent risk factors for PMV were higher body mass index (BMI) (p = 0.031), diabetes mellitus of the recipient (p = 0.039), ECMO support during surgery (p = 0.029) and intraoperative transfusion >5 red blood cell units (p < 0.001). Increased mortality rates were observed at one-year in recipients who received PMV (44% versus 15%, p < 0.001).

Conclusion

PMV was associated with increased morbidity and mortality one-year after LT. Preoperative risk factors (BMI and diabetes mellitus) must be considered when selecting and conditioning the recipients.

Off-pump implantation of left ventricular assist device via minimally invasive left thoracotomy: Our single-center experience

Background

The aim of this study was to compare our experience of left ventricular assist device implantation via minimally invasive left thoracotomy with off-pump versus on-pump technique.

Methods

Between June 2013 and April 2020, nine patients (8 males, 1 female; mean age: 47±11.9 years; range, 30 to 61 years) who underwent off-pump left ventricular assist device implantation and nine patients (8 males, 1 female; mean age: 47±11.4 years; range, 29 to 60 years) who underwent on-pump minimally invasive left thoracotomy were retrospectively analyzed. Postoperative outcomes and mid-term results of both groups were evaluated.

Results

Outflow graft was anastomosed to the ascending aorta with J-sternotomy in all patients. The median duration of intubation and intensive care unit stay were one (IQR: 1.5) day and eight (IQR: 6.5) days in the off-pump group, respectively and one (IQR: 0) day and seven (IQR: 7) days in the on-pump group, respectively. Intra-aortic balloon pump was needed during the weaning of cardiopulmonary bypass in one (11%) of the patients in both groups. Postoperative right ventricular failure was observed in two (22%) patients in the offpump group who were treated medically and recovered. There was no need for revision due to bleeding or postoperative extracorporeal membrane oxygenator implantation in either group. In the off-pump group, three patients underwent heart transplantation after median 854 (IQR: 960) days. Three patients died one month, two and four years after implantation. Three patients were still alive with left ventricular assist device and were being uneventfully followed for 365, 400, and 700 days after implantation.

Conclusion

Off-pump technique is safe and feasible option for implantation of left ventricular assist device via minimally invasive left thoracotomy.

Outcomes of preoperative antiplatelet therapy in patients with acute type A aortic dissection

BACKGROUND

Acute type A aortic dissection (ATAAD) is life-threatening and requires immediate surgery. Sudden chest pain may lead to a risk of misdiagnosis as an acute coronary syndrome and may lead to subsequent antiplatelet therapy (APT). We used the Chinese Acute Aortic Syndrome (AAS) Collaboration Database to study the effects of APT on clinical outcomes.

METHODS

The AAS database is a retrospective multicentre database where 31 of 3092 patients had APT with aspirin or clopidogrel or both before surgery. Before and after propensity score matching (PSM), the incidence of complications and mortality was compared between APT and non-APT patients by using a logistic regression model. The sample remaining after PSM was 30 in the APT group and 80 in the non-APT group.

RESULTS

The sample remaining after matching was 30 in the APT group and 80 in the non-APT group. We found 10 cases with percutaneous coronary intervention in the APT group (33.3%). The APT group received more volume of packed red blood cells, 8.4 ± 6.05 units; plasma, 401.67 ± 727 ml, and platelet transfusion (14.07 ± 8.92 units). The drainage volume was much more in the APT group (5009.37 ± 2131.44 ml, p = .004). Mortality was higher in APT group (26% vs. 10%, p = .027). The preoperative APT was an independent predictor of mortality (odds ratio: 6.808, 95% confidence interval: 1.554-29.828, p = .011).

CONCLUSION

APT before ATAAD repair was associated with more transfusions and higher early mortality. The timing of surgery should be carefully considered based on the patient's status and the surgeon's experience.

Blood Markers of Portal Hypertension Are Associated with Blood Loss and Transfusion Requirements during Orthotopic Liver Transplantation

There is increasing evidence that portal hypertension plays a major role in bleeding risk during orthotopic liver transplantation (OLT). We investigated the association between preoperative blood levels of von Willebrand factor (VWF) and soluble CD163 (sCD163), which are established markers of portal hypertension, and blood loss and transfusion requirements during OLT. We measured levels of VWF and sCD163 in preoperative serum samples of 168 adult patients undergoing a primary OLT between 1998 and 2012. Preoperative levels of VWF and sCD163 correlated with the model of end-stage liver disease (MELD) score (r = 0.414, p < 0.001 and r = 0.382, p < 0.001, respectively). Patients with high VWF or sCD163 levels (VWF and sCD163 levels above the median) had a substantially increased risk of needing red blood cell transfusion compared with patients with low VWF or sCD163 levels (VWF and sCD163 levels below the median) (odds ratio 3.5 [95% confidence interval, CI 1.7-7.0] and 2.3 [95% CI 1.1-4.5], respectively). Blood loss was highest in patients with both high VWF or sCD163 levels and a high preoperative international normalized ratio. Elevated blood levels of markers of portal hypertension are associated with increased blood loss and transfusion requirements during OLT and support the notion that portal hypertension is an important contributor to perioperative blood loss.

Hospitalization length, surgical duration, and blood lost among the approaches for total hip arthroplasty: a Bayesian network meta-analysis

Despite the numerous studies, there is no consensus concerning the best approach for total hip arthroplasty (THA), and debates are ongoing. The purpose of this study was to perform a Bayesian network meta-analysis (NMA) comparing several approaches for primary THA. The focus was on peri-operative outcomes: surgical duration, total estimated blood loss, and length of the hospitalization. This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of health care interventions. In October 2019, the main databases were accessed. All the clinical trials comparing two or more different approaches for primary THA were assessed. For the methodology quality assessment, the PEDro score was performed. The Software STATA MP was used for the statistical analyses. The NMA was performed through the routine for Bayesian hierarchical random-effects analysis with the inverse variance statistic method for continuous variables. Data from 4843 procedures was analysed. Between patient's demographic, good baseline comparability was found. The comparison total estimated blood loss detected statistically significant inconsistency (P = 0.01). The posterolateral approach reported the lowest value for the surgical duration. The test for overall inconsistency was statistically significant (P = 0.4). The posterolateral approach reported the shortest hospitalization length. The test for overall inconsistency was statistically significant (P = 0.9). The posterolateral approach reported shorter surgical duration and hospitalization length. Concerning the analysis of total estimated blood loss, no significant result was obtained. Data must be considered in the light of the limitations of the present study.

Preoperative Vitamin K Reduces Blood Transfusions at Time of Left Ventricular Assist Device Implant

BACKGROUND

Congestive heart failure patients have hepatic congestion and abnormal coagulation profiles, increasing perioperative bleeding at time of ventricular assist device implantation. This study examined the impact of the preoperative administration of vitamin K on perioperative blood transfusion requirements.

METHODS

Retrospectively, 190 patients met inclusion criteria. Patients received no vitamin K (n = 62) or two 10-mg doses of intravenous vitamin K (n = 128) in the 24 hours before assist device implantation. Primary end points included transfusion requirements and reexploration rates for bleeding. Secondary outcomes were pump thrombosis and in-hospital mortality.

RESULTS

Baseline characteristics were similar between the 2 groups, with slight differences (not statistically significant) noted in the Interagency Registry for Mechanically Assisted Circulatory Support profile and total bilirubin levels. The only significant difference noted was the year of implantation (P < .001). Blood product usage was significantly lower in the vitamin K group compared to the no vitamin K group (P < .001). Higher rates of reexploration for bleeding (29.7% vs 13.6%, P = .023) and death at hospital discharge (16.2% vs 2.8%, P = .004) were noted for the no vitamin K group compared with the vitamin K group. After adjusting for age, sex, race, body mass index, Interagency Registry for Mechanically Assisted Circulatory Support profile, total bilirubin, surgeon, and year of operation, reexploration rates and death did not achieve statistical significance. No statistically significant difference was observed in stroke and pump thrombosis rates between the 2 groups.

CONCLUSIONS

Preoperative vitamin K administration may help reduce blood product use without any increased risk for strokes or pump thrombosis.

Early Outcomes of Low Postoperative Bleeding after Off-Pump Coronary Artery Bypass Grafting

Objective

To investigate whether low bleeding influences the early outcomes after off-pump coronary artery bypass grafting (CABG).

Methods

Retrospective analysis of ischemic heart disease patients who underwent off-pump CABG from January 2013 to December 2017. Patients were divided into low-bleeding group (n=659) and bleeding group (n=270), according to total drainage from chest tube during the first postoperative 12 hours. Clinical material and early outcomes were compared between the groups.

Results

Baseline was similar in the two groups. Operation time was 270±51 min in the low-bleeding group and 235±46 min in the bleeding group (P<0.0001). The low-bleeding group presented smaller drainage during the first 12 h (237±47 ml) and shorter mechanical ventilation time (6.86±3.78 h) than the bleeding group (557±169 ml and 10.66±5.19 h, respectively) (P<0.0001). Hemodynamic status was more stable in the low-bleeding group (P<0.0001) and usage rate of more than two vasoactive agents in this group was lower than in the bleeding group (P<0.0001). Number of distal anastomosis, reoperation for bleeding, suddenly increase in chest tube output, intensive care unit (ICU) stay, hospital stay, and other early outcomes had no statistical significance between the groups (P>0.05).

Conclusion

Postoperative bleeding < 300 ml/12 h in off-pump CABG patients did not require blood product transfusion and reoperation and that would contribute to reduction in mechanical ventilation time and maintaining hemodynamic stability. Bleeding < 800 ml during the first postoperative 12 h did not increase infection rates and ICU length of stay.

Haemotherapy with Fibrinogen for Perioperative Bleeding Prevention-A View on Arterial Thrombogenesis and Myocardial Infarction in the Rat In Vivo

Major blood loss during cardiac surgery is associated with increased morbidity and mortality. Clinical pilot studies indicated that preoperative fibrinogen supplementation reduces postoperative blood loss without increasing thrombotic complications. However, an increase in fibrinogen concentration might rather aggravate pre-existing thrombosis than increase the incidence of thrombotic events. Therefore, we investigated, in the present study, whether fibrinogen supplementation influences (1) arterial thrombus formation, (2) the extent of myocardial infarction and (3) the cardioprotective effect of ischaemic preconditioning. Arterial thrombogenesis of the femoral artery was induced by topic FeCl₃ treatment in anaesthetised Wistar rats after pretreatment with 60 mg/kg (Fib_low), 120 mg/kg (Fib_high) or vehicle (Con). Vessel blood flow was monitored, and time to vessel occlusion was analysed as a marker for arterial thrombogenesis. In addition, regional myocardial I/R injury was induced by temporary left coronary artery occlusion in rats pretreated with or without fibrinogen supplementation. In additional groups, ischaemic preconditioning (IPC) was induced by 3 cycles of 5 min of ischaemia/reperfusion. In all groups, myocardial infarct size was determined by triphenyltetrazoliumchlorid staining. Arterial thrombogenesis was not affected by fibrinogen pretreatment. No differences in time until vessel occlusion between Con, Fib_low and Fib_high groups were observed. In addition, fibrinogen supplementation in low and high concentrations had no effect on infarct size after regional myocardial ischaemia and reperfusion (Fib_low: 66 ± 10%, Fib_high: 62 ± 9%; each ns vs. Con). IPC reduced infarct size from 62 ± 14% to 34 ± 12% (p < 0.05 vs. Con). Furthermore, both fibrinogen concentrations did not affect cardioprotection by ischaemic preconditioning (Fib_low + IPC: 34 ± 11%, Fib_high + IPC: 31 ± 13%; each ns vs. IPC). Haemotherapy with fibrinogen did not affect arterial thrombogenesis, myocardial infarction and the cardioprotective effect of ischaemic preconditioning.

Adverse Outcomes of Perioperative Red Blood Cell Transfusions in Coronary Artery Bypass Grafting in Hospital Universiti Sains Malaysia

BACKGROUND

Perioperative red blood cell (RBC) transfusion in coronary artery bypass grafting (CABG) has both benefits and harms. Our aim was to study the association between perioperative RBC transfusion and its adverse outcomes.

METHODS

This was a retrospective study of patients who underwent isolated CABG in Hospital Universiti Sains Malaysia, Kelantan, Malaysia, from 1 January 2013 until 31 December 2017. Data were collected from medical records, and comparisons were made between patients who received perioperative RBC transfusions and those who did not have adverse outcomes after CABG.

RESULTS

A total of 108 patients who underwent isolated CABG were included in our study, and 78 patients received perioperative RBC transfusions. Patients who received perioperative RBC transfusions compared to those who did not were significantly more likely to develop prolonged ventilatory support (21.8% versus 0%, P = 0.003), cardiac morbidity (14.1% versus 0%, P = 0.032), renal morbidity (28.2% versus 3.3%, P = 0.005) and serious infection (20.5% versus 3.3%, P = 0.037). With each unit of packed RBC transfusions, there was a significantly increased risk of prolonged ventilatory support (adjusted odds ratio [AOR] = 1.45; 95% confidence interval [CI] = 1.20-1.77; P < 0.001), cardiac morbidity (AOR =1.40; 95%CI = 1.01-1.79; P = 0.007), renal morbidity (AOR = 1.23; 95%CI = 1.03-1.45; P = 0.019) and serious infection (AOR = 1.31; 95%CI = 1.07-1.60; P = 0.009).

CONCLUSION

Perioperative RBC transfusion in isolated CABG patients is associated with increased risks of developing adverse events such as prolonged ventilatory support, cardiac morbidity, renal morbidity and serious infection.

Selective serotonin reuptake inhibitor use and outcomes following cardiac surgery-a systematic review

A high prevalence of depression is observed in patients undergoing cardiac surgery, and depression has been shown to be an independent predictor of morbidity and mortality in this patient population. Selective serotonin re-uptake inhibitors (SSRIs) are the first-line recommended therapy for depressive disorders, however due to their platelet inhibitory actions they have been associated with increased incidences of post-operative bleeding. This review has sought to address whether the use of SSRIs is associated with a higher rate of mortality, major adverse events or bleeding events following cardiac surgery. A retrospective literature search selected studies comparing the use of SSRIs with no SSRI use in patients undergoing cardiac surgery. Seven of the ten studies analysed reported no significant difference in mortality in SSRI users. Five of the seven studies reporting bleeding events demonstrated no significant difference in SSRI users. Three of the five studies reporting other significant morbidity demonstrated no significant difference in SSRI users. Our study demonstrates the safety of the use of SSRIs for the treatment of depressive disorders in patients undergoing cardiac surgery.

Demographic and epidemiologic characterization of transfusion recipients from four US regions: evidence from the REDS-III recipient database

BACKGROUND

Blood transfusion is one of the most common medical procedures during hospitalization in the United States. To understand the benefits of transfusion while mitigating potential risks, a multicenter database containing detailed information on transfusion incidence and recipient outcomes would facilitate research.

STUDY DESIGN AND METHODS

The Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) program has developed a comprehensive transfusion recipient database utilizing data from hospital electronic health records at 12 participating hospitals in four geographic regions. Inpatient and outpatient data on transfusion recipients from January 1, 2013 to December 31, 2014 included patient age, sex, ethnicity, primary diagnosis, type of blood product provided, issue location, pretransfusion and post-transfusion hemoglobin (Hgb), and hospital outcomes. Transfusion incidence per encounter was calculated by blood product and various patient characteristics.

RESULTS

During the 2-year study period, 80,362 (12.5%) inpatient encounters involved transfusion. Among inpatients, the most commonly transfused blood products were red blood cells (RBCs; 10.9% of encounters), followed by platelets (3.2%) and plasma (2.9%). Among patients who received transfusions, the median number of RBC units was one, the pretransfusion Hgb level was 7.6 g/dL, and the Hgb increment per unit was 1.4 g/dL. Encounter mortality increased with patient age, the number of units transfused, and the use of platelet or plasma products. The most commonly reported transfusion reaction was febrile nonhemolytic.

CONCLUSION

The database contains comprehensive data regarding transfusion use and patient outcomes. The current report describes an evaluation of the first 2 years of a planned, 4-year, linked blood donor-component-recipient database, which represents a critical new resource for transfusion medicine researchers.

Short-Term Experience with Off-Pump Versus On-Pump Implantation of the HeartWare Left Ventricular Assist Device

Implantation of left ventricular assist devices while avoiding cardiopulmonary bypass (CPB) may decrease bleeding and improve postoperative recovery. To understand the effectiveness of this approach, we reviewed the charts of 26 patients who underwent HeartWare left ventricular assist device (HVAD) implantation without use of CPB (off-CPB group) and 22 patients who had HVAD implanted with CPB (CPB group) with an emphasis on the 30 day postoperative period. Preoperatively, both groups had similar demographic, functional, and hemodynamic characteristics. Off-CPB patients had significantly shorter surgery times than CPB patients, 188.5 (161.5-213.3) min versus 265.0 (247.5-299.5) min, respectively; p < 0.001. Blood transfusion requirements during surgery and within the postoperative 48 hour period were significantly lower in the off-CPB group than in the CPB group (odds ratio: 5.9; 95% confidence interval: 1.1-31.1, p = 0.042). Compared with the CPB group, the off-CPB group patients had a shorter intubation time, 21 (17.4-48.5) hours versus 41 (20.6-258.4) hours; p = 0.042. Intensive care unit stay was 7.0 (4.75-13.5) days for off-CPB versus 10.0 (6.0-19.0) days for CPB (p = 0.256). The off-CPB approach allows HVAD to be implanted quickly with significantly less perioperative bleeding and transfusion requirements and facilitates postoperative rehabilitation.

Predictors of blood transfusion following total knee replacement at a tertiary care center in Central Saudi Arabia

OBJECTIVES

To examine the incidence and predictors of blood transfusion following total knee replacement (TKR). Methods: A retrospective study on 462 patients of primary TKR at National Guard Hospital, Riyadh, Kingdom of Saudi Arabia. Descriptive statistics were compared by blood transfusion status and significant variables were further included in the multivariable model. Results: Overall transfusion rate following TKR was 35.3%. Regression analyses identified bilateral surgery, low preoperative hemoglobin (Hb) level, and high amount of blood loss as predictors of blood transfusion.  Conclusion: Correction of Hb level prior to surgery, careful hemostasis, and avoiding bilateral surgery may reduce the rate of blood transfusion following TKR.

Point-of-Care Platelet Function Testing

Cardiopulmonary bypass has unpredictably deleterious effects on platelet function. Patients with cardiovascular disease have treatments aimed at reducing platelet aggregation and are at risk of excessive bleeding during surgery. Transfusion of blood products, particularly platelets, probably causes increased morbidity and mortality. Conversely, patients with excessive platelet aggregation are at risk of thrombotic complications—undesirable outcomes in the context of myocardial revascularization and prevention of stroke. Platelet function is difficult to monitor. Laboratory tests take time, and the results are not immediately available. Point-of-care (POC) testing of platelet function should facilitate the clinical management of bleeding patients by rationalizing platelet transfusion and avoiding unnecessary transfusion. Furthermore, POC platelet function could alert the clinician to risks of excessive platelet activation and measure the efficacy of antiplatelet therapy. This article outlines some of the POC platelet function monitors available as well as their potential applications.

Changes in potassium concentration and haematocrit associated with cardiopulmonary bypass in paediatric cardiac surgery

Introduction: A blood prime is frequently required for paediatric bypass surgery to maintain adequate haematocrit (Hct). However, stored blood can have high extracellular potassium levels and this study aims to investigate the effect of stored blood on the potassium concentration, both in the prime and subsequently in the patient after cardiopulmonary bypass (CPB) has been established. In neonatal surgery, the stored blood may be irradiated if there is a question of impaired immunity. Irradiation may cause a further increase in potassium levels.

Methods: Blood-primed circuits prepared for 320 consecutive paediatric bypass cases were analysed for electrolyte levels, Hct and acid-base status before and immediately after establishment of CPB. Patients were divided into three groups according to body weight (<5kg, 5—10 kg and > 10 kg) and both stored blood and irradiated blood primes were compared.

Results: The potassium concentration was above the physiological range in all bypass primes pre-CPB and was significantly higher when using irradiated blood (8.12 ± 2.54 mmol/L versus 4.94 ± 3.35 mmol/L, p < 0.0001).

Despite this, on commencing CPB, the potassium level remained within the physiological range in the majority of patients (4.16 ± 2.72 mmol/L for stored blood prime and 4.55 ± 1.01 mmol/L for irradiated blood, p = 0.02). However, in smaller patients (< 5 kg) who had irradiated blood prime potassium level > 7.0 mmol/L, there was resultant hyperkalaemia (5.60 ± 0.90 mmol/L) on commencing CPB, that returned to normal later. No adverse clinical events were associated with the hyperkalaemia. Hct was well maintained on CPB (22—25%) in all groups and was not related to patient weight.

Conclusion: Blood primes result in high potassium concentrations in the prime fluid that is more severe if irradiated blood is used. The concentration is not sufficient to cause hyperkalaemia in the patients on commencing CPB except when irradiated blood prime is used in infants < 5 kg. Hct is well maintained in all patient groups with the use of blood prime. Perfusion (2007) 22, 87—92.

Effect of intravenous iron on outcomes of acute kidney injury

BACKGROUND

Little is known about benefit versus risk in treating iron deficiency anemia with intravenous (IV) iron in patients with acute kidney injury (AKI). Concerns about adverse outcomes may dissuade use and could contribute to greater use of red blood cell (RBC) transfusion.

STUDY DESIGN AND METHODS

We performed a retrospective case-control study of patients with AKI who received IV iron (cases) compared to those with AKI without IV iron (controls).

RESULTS

We identified 67 cases and 67 controls matched for age, stage of chronic kidney disease, and severity of anemia (hemoglobin [Hb], 7.7 ± 0.1 mg/dL vs. 7.5 ± 0.1 mg/dL; p = 0.47). Cases tended to be sicker with longer length of stay (27 + 4 days vs. 15 + 1.3 days; p = 0.003) and more intensive care unit days (13 + 2 days vs. 5 + 1 days; p = 0.003), more often with diagnosis of sepsis and greater number of antibiotics used (2.7 ± 0.3 vs. 1.8 ± 0.2; p = 0.02). Sepsis and AKI preceded use of IV iron. Despite greater illness severity, there was no difference in dialysis (38.8% vs. 34.3%; p = 0.59), mortality (24% vs. 21%; p = 0.679), or severity and/or recovery of AKI. Discharge Hb was similar (9.0 ± 0.1 mg/dL vs. 9.1 ± 0.1 mg/dL; p = 0.47). IV iron was used later in the stay and hence the cases also had more RBC transfusions.

CONCLUSIONS

We were unable to find any adverse consequences of use of IV iron when used to treat anemia in patients with AKI in regard to recovery of AKI or mortality even in patients with a diagnosis of sepsis. Consideration of preemptive use of IV iron in AKI with severe anemia is warranted to determine if this would reduce RBC transfusion.

The effects of hyperoxaemia on tissue oxygenation in patients with a nadir haematocrit lower than 20% during cardiopulmonary bypass

Excessive haemodilution and the resulting anaemia during CPB is accompanied by a decrease in the total arterial oxygen content, which may impair tissue oxygen delivery. Hyperoxic ventilation has been proven to improve tissue oxygenation in different pathophysiological states of anaemic tissue hypoxia. The aim of this study was to examine the influence of arterial hyperoxaemia on tissue oxygenation during CPB. Records of patients undergoing isolated CABG with CPB were retrospectively reviewed. Patients with nadir haematocrit levels below 20% during CPB were included in the study. Tissue hypoxia was defined as hyperlactataemia (lactate >2.2 mmol/L) coupled with low ScVO2 (ScVO2 <70%) during CPB. One hundred patients with normoxaemia and 100 patients with hyperoxaemia were included in the study. Patients with hyperoxaemia had lower tissue hypoxia incidence than patients with normoxaemia (p<0.001). Compared with patients without tissue hypoxia, patients with tissue hypoxia had significantly lower PaO2 values (p<0.001) and nadir haematocrit levels (p<0.001). Nadir haematocrit levels <18% (OR: 5.3; 95% CI: 2.67-10.6; p<0.001) and hyperoxaemia (OR: 0.28; 95% CI: 0.14-0.56; p<0.001) were independently associated with tissue hypoxia.

CONCLUSIONS

Hyperoxaemia during CPB may be protective against tissue hypoxia in patients with nadir haematocrit levels <20%.

Transfusions and blood loss in total hip and knee arthroplasty: a prospective observational study

BACKGROUND

There is a high prevalence of blood product transfusions in orthopedic surgery. The reported prevalence of red blood cell transfusions in unselected patients undergoing hip or knee replacement varies between 21% and 70%. We determined current blood loss and transfusion prevalence in total hip and knee arthroplasty when tranexamic acid was used as a routine prophylaxis, and further investigated potential predictors for excessive blood loss and transfusion requirement.

METHODS/MATERIALS

In total, 193 consecutive patients undergoing unilateral hip (n = 114) or knee arthroplasty (n = 79) were included in a prospective observational study. Estimated perioperative blood loss was calculated and transfusions of allogeneic blood products registered and related to patient characteristics and perioperative variables.

RESULTS

Overall transfusion rate was 16% (18% in hip patients and 11% in knee patients, p = 0.19). Median estimated blood loss was significantly higher in hip patients (984 vs 789 mL, p < 0.001). Preoperative hemoglobin concentration was the only independent predictor of red blood cell transfusion in hip patients while low hemoglobin concentration, body mass index, and operation time were independent predictors for red blood cell transfusion in knee patients.

CONCLUSIONS

The prevalence of red blood cell transfusion was lower than previously reported in unselected total hip or knee arthroplasty patients. Routine use of tranexamic acid may have contributed. Low preoperative hemoglobin levels, low body mass index, and long operation increase the risk for red blood cell transfusion.

Minimally invasive and alternative approaches for long-term LVAD placement: the Vanderbilt strategy

BACKGROUND

Minimally invasive and alternative strategies for implantation have been anecdotally reported for contemporary continuous-flow left ventricular assist device (CF-LVAD) placement.

METHODS

We reviewed our experience at a single center with alternative strategies for implantation of the HeartMate II and HeartWare CF-LVADs, in patients with advanced heart failure (HF). This featured article focuses on the associated surgical techniques and patient management pitfalls.

RESULTS

For appropriately selected cases, our group believes that these alternative strategies allow for the development of novel and less traumatic surgical approaches for CF-LVAD implantation. With reproducible outcomes, these approaches also promise the possibility of increasing the number of high-risk surgical patients who could benefit from CF-LVAD therapies.

CONCLUSIONS

This work has detailed a variety of less invasive alternative strategies for implantation of long-term LVADs. These newer approaches have the potential for significant advancements in the field of cardiothoracic surgery. Large-scale collaborative studies will be needed to clarify the potential advantages and disadvantages of these novel techniques on patient outcomes.

Effects of storage-aged red blood cell transfusions on endothelial function in hospitalized patients

BACKGROUND

Clinical and animal studies indicate that transfusions of older stored red blood cells (RBCs) impair clinical outcomes as compared to fresh RBC transfusions. It has been suggested that this effect is due to inhibition of nitric oxide (NO)-mediated vasodilation after transfusion of older RBC units. However, to date this effect has not been identified in human transfusion recipients.

STUDY DESIGN AND METHODS

Forty-three hospitalized patients with transfusion orders were randomly assigned to receive either fresh (<14 days) or older stored (>21 days) RBC units. Before transfusion, and at selected time points after the start of transfusion, endothelial function was assessed using noninvasive flow-mediated dilation assays.

RESULTS

After transfusion of older RBC units, there was a significant reduction in NO-mediated vasodilation at 24 hours after transfusion (p = 0.045), while fresh RBC transfusions had no effect (p = 0.231).

CONCLUSIONS

This study suggests for the first time a significant inhibitory effect of transfused RBC units stored more than 21 days on NO-mediated vasodilation in anemic hospitalized patients. This finding lends further support to the hypothesis that deranged NO signaling mediates adverse clinical effects of older RBC transfusions. Future investigations will be necessary to address possible confounding factors and confirm these results.

Post-operative depletion of platelet count is associated with anastomotic insufficiency following intrahepatic cholangiojejunostomy: a case-control study from the results of 220 cases of intrahepatic cholangiojejunostomy

Background

Post-operative anastomotic insufficiency following major hepato-biliary surgery has significant impacts on the post-operative course. Recent reports have revealed that platelets play an important role in liver regeneration and wound healing. From these experimental and clinical results on platelet function, we hypothesized that post-operative platelet depletion (to <10 × 10⁴/μL) would be associated with delayed liver regeneration as well as anastomotic insufficiency of intrahepatic cholangiojejunostomy. However, little information is available regarding correlations between platelet count and these complications. The purposes of the present study were, firstly, to evaluate the incidence of anastomotic insufficiency following intrahepatic cholangiojejunostomy and, secondly, to evaluate whether platelet depletion represents a risk factor for anastomotic insufficiency in intrahepatic cholangiojejunostomy.

Methods

Participants in this study comprised 220 consecutive patients who underwent intrahepatic cholangiojejunostomy following hepato-biliary resection for biliary malignancies between September 1998 and December 2010. Anastomotic insufficiency was confirmed by cholangiographic demonstration of leakage from the anastomosis using contrast medium introduced via a biliary drainage tube or prophylactic drain placed during surgery.

Results

Anastomotic insufficiency of the intrahepatic cholangiojejunostomy occurred in 13 of 220 patients (6%). Thirteen of the 220 patients, including one with anastomotic insufficiency, died during the study. Uni- and multivariate analyses both revealed that platelet depletion on post-operative day 1 (<10 × 10⁴/μL) correlated with anastomotic insufficiency.

Conclusion

Post-operative platelet depletion was closely associated with anastomotic insufficiency following intrahepatic cholangiojejunostomy. This correlation has been established, but the underlying mechanisms have not.

Contaminated heparin and outcomes after cardiac surgery: a retrospective propensity-matched cohort study

Background

During 2007 and 2008 it is likely that millions of patients in the US received heparin contaminated (CH) with oversulfated chondroitin sulfate, which was associated with anaphylactoid reactions. We tested the hypothesis that CH was associated with serious morbidity, mortality, intensive care unit (ICU) stay and heparin-induced thrombocytopenia following adult cardiac surgery.

Methods and Findings

We conducted a single center, retrospective, propensity-matched cohort study during the period of CH and the equivalent time frame in the three preceding or the two following years. Perioperative data were obtained from the institutional record of the Society of Thoracic Surgeons National Database, for which the data collection is prospective, standardized and performed by independent investigators. After matching, logistic regression was performed to evaluate the independent effect of CH on the composite adverse outcome (myocardial infarction, stroke, pneumonia, dialysis, cardiac arrest) and on mortality. Cox regression was used to determine the association between CH and ICU length of stay. The 1∶5 matched groups included 220 patients potentially exposed to CH and 918 controls. There were more adverse outcomes in the exposed cohort (20.9% versus 12.0%; difference = 8.9%; 95% CI 3.6% to 15.1%, P<0.001) with an odds ratio for CH of 2.0 (95% CI, 1.4 to 3.0, P<0.001). In the exposed group there was a non-significant increase in mortality (5.9% versus 3.5%, difference = 2.4%; 95% CI, −0.4 to 3.5%, P = 0.1), the median ICU stay was longer by 14.1 hours (interquartile range −26.6 to 79.8, S = 3299, P = 0.0004) with an estimated hazard ratio for CH of 1.2 (95% CI, 1.0 to 1.4, P = 0.04). There was no difference in nadir platelet counts between cohorts.

Conclusions

The results from this single center study suggest the possibility that contaminated heparin might have contributed to serious morbidity following cardiac surgery.

Transfusion strategy: impact of haemodynamics and the challenge of haemodilution

Blood transfusion is associated with increased morbidity and mortality and numerous reports have emphasised the need for reduction. Following this there is increased attention to the concept of patient blood management. However, bleeding is relatively common following cardiac surgery and is further enhanced by the continued antiplatelet therapy policy. Another important issue is that cardiopulmonary bypass leads to haemodilution and a potential blood loss. The basic role of blood is oxygen transport to the organs. The determining factors of oxygen delivery are cardiac output, haemoglobin, and saturation. If oxygen delivery/consumption is out of balance, the compensation mechanisms are simple, as a decrease in one factor results in an increase in one or two other factors. Patients with coexisting cardiac diseases may be of particular risk, but studies indicate that patients with coexisting cardiac diseases tolerate moderate anaemia and may even benefit from a restrictive transfusion regimen. Further it has been shown that patients with reduced left ventricular function are able to compensate with increased cardiac output in response to bleeding and haemodilution if normovolaemia is maintained. In conclusion the evidence supports that each institution establishes its own patient blood management strategy to both conserve blood products and maximise outcome.

Does discharge hemoglobin affect medium-term survival after coronary bypass?

BACKGROUND

the effect of discharge hemoglobin on survival of patients undergoing isolated coronary artery bypass grafting is unknown. Blood transfusion frequently confounds the issue.

METHODS

4682 consecutive patients undergoing isolated coronary artery bypass were studied. Univariate and multivariate analyses were performed to identify whether discharge hemoglobin was an independent risk factor determining survival after isolated coronary artery bypass. The analysis was complemented with a neuronal network.

RESULTS

univariate analysis identified discharge hemoglobin (p = 0.01) and blood transfusion (p < 0.0001) as significant factors affecting survival. Multivariate analysis identified age (p < 0.0001) ejection fraction (p < 0.0001), dialysis (p < 0.0001), peripheral vascular disease (p = 0.001), preoperative hemoglobin (p = 0.01), and blood transfusion (p = 0.0002) as significant factors determining survival. Neuronal network analysis confirmed the lack of importance of hemoglobin on discharge as a factor determining survival.

CONCLUSIONS

the discharge hemoglobin level does not affect medium-term survival.

Platelet transfusions are not associated with increased morbidity or mortality in cardiac surgery

PURPOSE

To determine the independent relationship between leukoreduced platelet transfusions and adverse events in cardiac surgery.

METHODS

In this observational study, detailed baseline and perioperative data were prospectively collected on consecutive patients who underwent cardiac surgery at a single institution from 1999 to 2004. The independent associations of platelet transfusion with clinical outcomes (low output syndrome, myocardial infarction, stroke, renal failure, sepsis, and death) were determined by multivariable logistic regression analysis and propensity score case-control analysis.

RESULTS

Of the 11,459 patients analyzed, 2,174 (19%) received (leukoreduced) platelets - 1,408 received 5 U, 471 received 10 U, 140 received 15 U, and 155 received 20 or more units. Although all measured adverse event rates were higher in those who received platelets, in neither the logistic regression analyses nor the propensity score analyses was there any association between platelet transfusion and any of the adverse events.

CONCLUSIONS

Transfusion of leukoreduced platelets in cardiac surgery is not associated with adverse clinical outcomes when adjustments are made for important confounders.

Risks associated with the transfusion of various blood products in aortic valve replacement

BACKGROUND

Patients undergoing cardiac operations often require transfusions of red blood cells, plasma, and platelets. From a statistical point of view, there is a significant collinearity between the components, but they differ in indications for use and composition. This study explores the relationship between the transfusion of different blood components and long-term mortality in patients undergoing aortic valve replacement alone or combined with revascularization.

METHODS

A retrospective single-center study was performed including 1,311 patients undergoing aortic valve replacement. Patients who received more than 7 units of red blood cells, those who died early (7 days), and emergency cases were excluded. Patients were monitored for up to 9.5 years. A broad selection of potential risk factors were analyzed using Cox proportional hazards regression, where transfusion of red blood cells, plasma, and platelets were forced to remain in the model.

RESULTS

The transfusion of red blood cells was not associated with decreased long-term survival (hazard ratio [HR], 1.01; p = 0.520) nor was the transfusion of platelets (HR, 0.946; p = 0.124); however, the transfusion of plasma was (HR, 1.041; p < 0.001). All HRs are per unit of blood product transfused. No increased risk was found for patients undergoing a combined procedure.

CONCLUSIONS

No significant risk for long-term mortality was associated with transfusion of red blood cells during the study period. However, the transfusion of plasma was associated with increased mortality.

Blood transfusion and infection after cardiac surgery

Cardiac surgery is the largest consumer of blood products in medicine; although believed life saving, transfusion carries substantial adverse risks. This study characterizes the relationship between transfusion and risk of major infection after cardiac surgery. In all, 5,158 adults were prospectively enrolled to assess infections after cardiac surgery. The most common procedures were isolated coronary artery bypass graft surgery (31%) and isolated valve surgery (30%); 19% were reoperations. Infections were adjudicated by independent infectious disease experts. Multivariable Cox modeling was used to assess the independent effect of blood and platelet transfusions on major infections within 60 ± 5 days of surgery. Red blood cells (RBC) and platelets were transfused in 48% and 31% of patients, respectively. Each RBC unit transfused was associated with a 29% increase in crude risk of major infection (p < 0.001). Among RBC recipients, the most common infections were pneumonia (3.6%) and bloodstream infections (2%). Risk factors for infection included postoperative RBC units transfused, longer duration of surgery, and transplant or ventricular assist device implantation, in addition to chronic obstructive pulmonary disease, heart failure, and elevated preoperative creatinine. Platelet transfusion decreased the risk of infection (p = 0.02). Greater attention to management practices that limit RBC use, including cell salvage, small priming volumes, vacuum-assisted venous return with rapid autologous priming, and ultrafiltration, and preoperative and intraoperative measures to elevate hematocrit could potentially reduce occurrence of major postoperative infections.

Association between intraoperative blood transfusions and early postoperative delirium in older adults

OBJECTIVES

To determine whether intraoperative blood transfusion, a known trigger and amplifier of inflammation, is an independent risk factor for early postoperative delirium (POD), an acute state of confusion with fluctuating consciousness and inattention after surgery, in older adults undergoing surgery.

DESIGN

Secondary analysis using a database created for a prospective cognitive outcomes study.

SETTING

University hospital.

PARTICIPANTS

Four hundred seventy-two individuals aged 65 and older undergoing major noncardiac surgery.

MEASUREMENTS

Perioperative data were examined for association with POD on the first postoperative day. Multivariable logistic regression analysis was conducted to determine whether intraoperative blood transfusion independently predicts POD after adjusting for covariates known to be associated with onset of delirium and blood transfusions.

RESULTS

One hundred thirty-seven individuals (29%) developed delirium on the first postoperative day. The multivariable logistic regression model identified age, sex, history of central nervous system disorder, preoperative cognitive dysfunction, and pain, as well as blood transfusions, as independent risk factors for POD. Intraoperative administration of more than 1,000 mL of red blood cells (RBCs) was the strongest predictor of POD on the first postoperative day (odds ratio = 3.68; 95% confidence interval = 1.32–10.94; P < .001).

CONCLUSION

Intraoperative blood transfusion of more than 1,000 mL of RBCs increases the risk of delirium on the first postoperative day in older adults undergoing noncardiac surgery.

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.

Increased long-term mortality with plasma transfusion after coronary artery bypass surgery

PURPOSE

Patients undergoing cardiac surgery often require transfusions of red blood cells, plasma and platelets. These components differ widely in both indications for use and composition. However, from a statistical point of view there is a significant colinearity between the components. This study explores the relation between the transfusion of different blood components and long-term mortality.

METHODS

A retrospective single-centre study was performed including 5,261 coronary artery bypass grafting patients, excluding patients receiving more than eight units of red blood cells, those suffering early death (7 days) and emergency cases. Patients were followed up for a period of up to 7.5 years. A broad spectrum of potential risk factors was analysed using Cox proportional hazards survival regression. Non-significant risk factors were removed by step-wise elimination, and transfusion of red blood cells, plasma and platelets was forced to remain in the model.

RESULTS

The transfusion of red blood cells was not associated with decreased long-term mortality (HR = 1.007, p = 0.775), whereas the transfusion of plasma was associated with decreased long-term survival (HR = 1.060, p < 0.001), and the transfusion of platelets was associated with increased long-term survival (HR = 0.817, p = 0.011). The risk associated with transfusion of plasma was mainly attributed to patients receiving large amounts of plasma. All hazard ratios are per unit of blood product transfused.

CONCLUSIONS

No association was found between the transfusion of red blood cells and mortality during the study period. However, transfusion of plasma was associated with increased mortality while transfusion of platelets was associated with decreased mortality during the study period.

Risks of harms using antifibrinolytics in cardiac surgery: systematic review and network meta-analysis of randomised and observational studies

OBJECTIVE

To estimate the relative risks of death, myocardial infarction, stroke, and renal failure or dysfunction between antifibrinolytics and no treatment following the suspension of aprotinin from the market in 2008 for safety reasons and its recent reintroduction in Europe and Canada.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

A Cochrane review of antifibrinolytic treatments was chosen as the starting point for this systematic review. Medline, Embase, and the Cochrane register of trials were searched with no date restrictions for observational evidence.

STUDY SELECTION

Propensity matched or adjusted observational studies with two or more of the interventions of interest (aprotinin, tranexamic acid, epsilon-aminocaproic acid, and no treatment) that were carried out in patients undergoing cardiac surgery.

DATA ANALYSIS

Network meta-analysis was used to compare treatments, and odds ratios with 95% credible intervals were estimated. Meta-analyses were carried out for randomised controlled trials alone and for randomised controlled trials with observational studies.

RESULTS

106 randomised controlled trials and 11 observational studies (43,270 patients) were included. Based on the results from analysis of randomised controlled trials, tranexamic acid was associated on average with a reduced risk of death compared with aprotinin (odds ratio 0.64, 95% credible interval 0.41 to 0.99). When observational data were incorporated, comparisons showed an increased risk of mortality with aprotinin on average relative to tranexamic acid (odds ratio 0.71, 95% credible interval 0.50 to 0.98) and epsilon-aminocaproic acid (0.60, 0.43 to 0.87), and an increased risk of renal failure or dysfunction on average relative to all comparators: odds ratio 0.66 (95% credible interval 0.45 to 0.88) compared with no treatment, 0.66 (0.48 to 0.91) versus tranexamic acid, and 0.65 (0.45 to 0.88) versus epsilon-aminocaproic acid.

CONCLUSION

Although meta-analyses of randomised controlled trials were largely inconclusive, inclusion of observational data suggest concerns remain about the safety of aprotinin. Tranexamic and epsilon-aminocaproic acid are effective alternatives that may be safer for patients.

Antiplatelet drugs: mechanisms and risks of bleeding following cardiac operations

Preoperative antiplatelet drug use is common in patients undergoing coronary artery bypass grafting (CABG). The impact of these drugs on bleeding and blood transfusion varies. We hypothesize that review of available evidence regarding drug-related bleeding risk, underlying mechanisms of platelet dysfunction, and variations in patient response to antiplatelet drugs will aid surgeons as they assess preoperative risk and attempt to limit perioperative bleeding. The purpose of this review is to (1) examine the role that antiplatelet drugs play in excessive postoperative blood transfusion, (2) identify possible mechanisms to explain patient response to antiplatelet drugs, and (3) formulate a strategy to limit excessive blood product usage in these patients. We reviewed available published evidence regarding bleeding risk in patients taking preoperative antiplatelet drugs. In addition, we summarized our previous research into mechanisms of antiplatelet drug-related platelet dysfunction. Aspirin users have a slight but significant increase in blood product usage after CABG (0.5 U of nonautologous blood per treated patient). Platelet adenosine diphosphate (ADP) receptor inhibitors are more potent antiplatelet drugs than aspirin but have a half-life similar to aspirin, around 5 to 10 days. The American Heart Association/American College of Cardiology and the Society of Thoracic Surgeons guidelines recommend discontinuation, if possible, of ADP inhibitors 5 to 7 days before operation because of excessive bleeding risk, whereas aspirin should be continued during the entire perioperative period in most patients. Individual variability in response to aspirin and other antiplatelet drugs is common with both hyper- and hyporesponsiveness seen in 5 to 25% of patients. Use of preoperative antiplatelet drugs is a risk factor for increased perioperative bleeding and blood transfusion. Point-of-care tests can identify patients at high risk for perioperative bleeding and blood transfusion, although these tests have limitations. Available evidence suggests that multiple blood conservation techniques benefit high-risk patients taking antiplatelet drugs before operation. Guidelines for patients who take aspirin and/or thienopyridines before cardiac procedures include some or all of the following: (1) preoperative identification of high-risk patients using point-of-care testing; (2) withdrawal of aspirin or other antiplatelet drugs for a few days and delay of operation in patients at high risk for bleeding if clinical circumstances permit; (3) selective perioperative use of evidence-based blood conservation interventions (e.g., short-course erythropoietin, off-pump procedures, and use of intraoperative blood conservation techniques), especially in high-risk patients; and (4) platelet transfusions if clinical bleeding occurs.