Variability in transfusion practice for coronary artery bypass surgery persists despite national consensus guidelines: a 24-institution study. Institutions of the Multicenter Study of Perioperative Ischemia Research Group

Fresh-frozen plasma transfusion did not reduce 30-day mortality in patients undergoing cardiopulmonary bypass cardiac surgery with excessive bleeding: the PLASMACARD multicenter cohort study

BACKGROUND

During on-pump cardiac surgery, hemorrhagic complications occur frequently. Fresh-frozen plasma (FFP) is widely transfused to provide coagulation factors. Yet, no randomized clinical trial has demonstrated its benefits on mortality. We assessed the relationship between therapeutic transfusion of FFP and 30-day mortality in cardiac surgery patients suffering from excessive bleeding in a prospective cohort study.

STUDY DESIGN AND METHODS

Adult patients who underwent on-pump cardiac surgery and experienced excessive bleeding during the 48-hour perioperative period were recruited from 15 French centers between February 2004 and January 2006. Patients who received a preventive FFP transfusion were excluded. The association between FFP transfusion and all cause 30-day mortality was estimated using a Cox proportional hazards model, adjusted for confounding. A propensity score (PS) sensitivity analysis was also performed.

RESULTS

Among 967 patients included in this study, 58.1% received FFP. The median dose was 11.3 mL/kg (interquartile range, 7.6-19.5). The cumulative 30-day mortality rate was 11.3% (95% confidence interval [CI], 9.5-13.5). FFP transfusion was associated with a higher 30-day mortality (hazard ratio [HR], 3.2; 95% CI, 1.7-6.1) in univariate analysis; however, after adjusting for prognostic factors, there was no longer any association (HR, 1.5; 95% CI, 0.8-3.0, p = 0.20). The results of the PS analysis were consistent with the adjusted analysis.

CONCLUSION

Among on-pump cardiac surgery patients experiencing excessive perioperative bleeding, there is no evidence of a beneficial impact of FFP transfusion on mortality.

Concepts of blood transfusion in adults

Recent progress has been made in the identification and implementation of best transfusion practices on the basis of evidence-based clinical trials, published clinical practice guidelines, and process improvements for blood use and clinical patient outcomes. However, substantial variability persists in transfusion outcomes for patients in some clinical settings--eg, patients undergoing cardiothoracic surgery. This variability could be the result of insufficient understanding of published guidelines; different recommendations of medical societies, including the specification of a haemoglobin concentration threshold to use as a transfusion trigger; the value of haemoglobin as a surrogate indicator for transfusion benefit, even though only changes in concentration and not absolute red cell mass of haemoglobin can be identified; and disagreement about the validity of the level 1 evidence for clinical practice guidelines. Nevertheless, institutional experience and national databases suggest that a restrictive blood transfusion approach is being increasingly implemented as best practice.

Early thromboelastometric variables reliably predict maximum clot firmness in patients undergoing cardiac surgery: a step towards earlier decision making

BACKGROUND

While much effort has been spent on guiding coagulation and transfusion therapy in patients undergoing cardiopulmonary bypass (CPB) surgery, the use of conventional laboratory-based coagulation tests is hampered by long turnaround times and interference with heparin and protamine. To allow faster assessment of maximum clot firmness (MCF) by point-of-care thromboelastometry (ROTEM®, TEM International GmbH, Munich, Germany), we tested whether clotting time (CT), clot formation time (CFT), or early values of clot firmness (CF) predict MCF.

METHODS

Results of 437 ROTEM® assays (EXTEM®, INTEM®, FIBTEM®, and HEPTEM®) from 84 patients undergoing CPB surgery were analyzed. Measurements were performed prior to and after heparin administration, as well as after protamine administration and CT, CFT, and CF after 5, 10, and 15 min (A5, A10, and A15) after initial clotting (CT) were related to MCF.

STATISTICS

Regression and Bland-Altman analyses and receiver-operating characteristics (ROCs).

RESULTS

CFT (r = 0.87-0.95), A5 (r = 0.84-0.98; P < 0.0001), A10 (r = 0.86-0.98; P < 0.0001), and A15 (r = 0.86-0.98; P < 0.0001) demonstrated high correlation coefficients with MCF, whereas CT correlated weakly (r = 0.07-0.41). As expected, correlation coefficients increased with the time allowed to assess a specific variable. ROC analyses demonstrated excellent accuracy for CFT, A5, A10, and A15 [area under the curve (AUC): 0.9476-0.9931] to predict a subnormal MCF, whereas CT demonstrated poor accuracy (AUC: 0.5796-0.6774).

CONCLUSION

Taking into account specific bias, early values of CF (A5-A15) reliably predict maximum CF under all conditions and, therefore, allow for marked time savings in the interpretation of ROTEM® measurements. This may guide earlier and more specific treatment of CPB-related coagulation disorders.

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.

Variation of blood transfusion in patients undergoing major noncardiac surgery

OBJECTIVE

To examine the hospital variability in use of red blood cells (RBCs), fresh-frozen plasma (FFP), and platelet transfusions in patients undergoing major noncardiac surgery.

BACKGROUND

Blood transfusion is commonly used in surgical procedures in the United States. Little is known about the hospital variability in perioperative transfusion rates for noncardiac surgery.

METHODS

We used the University HealthSystem Consortium database (2006-2010) to examine hospital variability in use of allogeneic RBC, FFP, and platelet transfusions in patients undergoing major noncardiac surgery. We used regression-based techniques to quantify the variability in hospital transfusion practices and to study the association between hospital characteristics and the likelihood of transfusion.

RESULTS

After adjusting for patient risk factors, hospital transfusion rates varied widely for patients undergoing total hip replacement (THR), colectomy, and pancreaticoduodenectomy. Compared with patients undergoing THR in average-transfusion hospitals, patients treated in high-transfusion hospitals have a greater than twofold higher odds of being transfused with RBCs [adjusted odds ratio (AOR) = 2.41; 95% confidence interval (CI), 1.89-3.09], FFP (AOR = 2.81; 95% CI, 2.02-3.91), and platelets (AOR = 2.52; 95% CI, 1.95-3.25), whereas patients in low-transfusion hospitals have an approximately 50% lower odds of receiving RBCs (AOR = 0.45; 95% CI, 0.35-0.57), FFP (AOR = 0.37; 95% CI, 0.27-0.51), and platelets (AOR = 0.42; 95% CI, 0.29-0.62). Similar results were obtained for colectomy and pancreaticoduodenectomy.

CONCLUSIONS

There was dramatic hospital variability in perioperative transfusion rates among patients undergoing major noncardiac surgery at academic medical centers. In light of the potential complications of transfusion therapy, reducing this variability in hospital transfusion practices may result in improved surgical outcomes.

Thromboelastography in the Assessment of Bleeding Following Surgery for Congenital Heart Disease

Background: Perioperative bleeding is common in pediatric cardiac surgery patients. Traditional laboratory tests do not adequately characterize coagulation derangements in patients with bleeding. We sought to establish preoperative thromboelastography parameters in children prior to cardiopulmonary bypass, to compare thromboelastography assessment with standard coagulation parameters postoperatively, and to assess thromboelastography in children with significant hemorrhage. Methods: Sixty patients requiring cardiopulmonary bypass were enrolled in a prospective observational study of perioperative thromboelastography. Thromboelastography measures were obtained preoperatively, intraoperatively after protamine administration, upon admit to the intensive care unit, and when patients were treated for bleeding. Thromboelastography measures were not used for clinical care. Postoperative thromboelastography measurements were compared with the standard coagulation parameters. Intraoperative thromboelastography, postoperative thromboelastography, and clinical outcomes were compared among patients who did and did not have significant postoperative bleeding. Results: Preoperative thromboelastography parameters were similar to other published normal values for pediatric patients. Transfusion recommendations based on thromboelastography measurements were significantly different from those based on the standard coagulation testing. Thromboelastography measures after initial protamine administration were significantly different in patients with postoperative bleeding. This difference was not present upon arrival to the intensive care unit. Patients with significant bleeding tended to cease bleeding when clinical interventions were in agreement with recommendations based on thromboelastography. Conclusions: Pediatric patients with significant postoperative bleeding after surgery are more likely to have abnormal thromboelastography early after cessation of cardiopulmonary bypass. Thromboelastography illustrates derangements in the coagulation system and may aid in the treatment of postoperative bleeding.

Effect of hospital culture on blood transfusion in cardiac procedures

BACKGROUND

In our effort to reduce the use of blood products in cardiac operations in a health care system, we noted variations in transfusion practices among facilities. Interestingly, surgeons practicing at the same hospital had similar transfusion rates. We sought to quantitate the contribution of hospital influence on individual surgeons' transfusion practices.

METHODS

Blood transfusion data for coronary artery bypass graft operations at 12 Providence Health & Services facilities between January 2008 and June 2011 were reviewed. Frequency of perioperative blood transfusion, amount of transfusion, components transfused, and timing of transfusions were compared. Variation among surgeons at the same institution vs between institutions was computed based on multilevel mixed-effect logistic and linear regression models. Intraclass correlation coefficients were calculated.

RESULTS

A total of 5,744 nonemergency first-time coronary artery bypass graft procedures were performed by 42 not-low volume (n>30 in 2.5 years) surgeons at 12 Providence Health & Services hospitals during the 3.5-year study period. Frequency, amount, timing, and blood component usage were different among facilities but relatively similar for surgeons within a facility. The variance of red blood cell transfusion rate among hospitals (.82) is more than two times that among surgeons practicing within the same hospital (.35). Thus, surgeons contribute 30% to the variation, and 70% of the total variation can be explained by the hospital effect.

CONCLUSIONS

In our multihospital system, the hospital that a surgeon practices at plays a larger role in determining blood utilization than the individual surgeon's preference.

Predictors of transfusion of packed red blood cells in coronary artery bypass grafting surgery

OBJECTIVES

Finding predictors of blood transfusion may facilitate the most efficient approach for the use of blood bank services in coronary artery bypass grafting procedures. The aim of this retrospective study is to identify preoperative and intraoperative patient characteristics predicting the need for blood transfusion during or after CABG in our local cardiac surgical service.

METHODS

435 patients undergoing isolated first-time CABG were reviewed for their preoperative and intraoperative variables and analyzed postoperative data. Patients were 255 males and 180 females, with mean age 62.01 ± 10.13 years. Regression logistic analysis was used for identifying the strongest perioperative predictors of blood transfusion.

RESULTS

Blood transfusion was used in 263 patients (60.5%). The mean number of transfused blood products units per patient was 2.27 ± 3.07 (0-23) units. The total number of transfused units of blood products was 983. Univariate analysis identified age >65 years, weight <70 Kg, body mass index <25 Kg/m2, hemoglobin <13mg/dL, hematocrit < 40% and ejection fraction <50%, use of cardiopulmonary bypass (CPB), not using an internal thoracic artery as a bypass, and multiple bypasses as significant predictors. The strongest predictors using multivariate analysis were hematocrit < 40% (OR 2.58; CI 1.62-4.15; P<0.001), CPB use (OR 2.00; CI 1.27-3.17; P=0.003) and multiple bypasses (OR 2.31; CI 1.31-4.08; P=0.036).

CONCLUSIONS

The identification of these risk factors leads to better identification of patients with a greater probability of using blood, allocation blood bank resources and cost-effectiveness use of blood products.

Pump blood processing, salvage and re-transfusion improves hemoglobin levels after coronary artery bypass grafting, but affects coagulative and fibrinolytic systems

Cell saving systems are commonly used during cardiac operations to improve hemoglobin levels and to reduce blood product requirements. We analyzed the effects of residual pump blood salvage through a cell saver on coagulation and fibrinolysis activation and on postoperative hemoglobin levels. Thirty-four elective coronary artery bypass graft (CABG) patients were randomized. In 17 patients, residual cardiopulmonary bypass (CPB) circuit blood was transfused after the cell saving procedure (cell salvage group). In the other 17 patients, residual CPB circuit blood was discarded (control group). Activation of the coagulative, fibrinolytic and inflammatory systems was evaluated pre-operatively (Pre), 2 hours after the termination of CPB (T0) and 24 hours postoperatively (T1), measuring prothrombin fragment 1.2 (PF 1.2), plasmin-anti-plasmin (PAP), plasminogen activator inhibitor-1 (PAI-1) and interleukin-6 (IL-6). The cell salvage group of patients had a significant improvement in hemoglobin levels after processed blood infusion (2.7 ± 1.7 g/dL vs 1.2 ± 1.1 g/dL; p=0.003). PF1.2 levels were significantly higher after infusion (T0: 1175 ± 770 pmol/L vs 730 ± 237 pmol/L; p=0.037; T1: 331 ± 235 pmol/L vs 174 ± 134 pmol/L; p=0.026). Also, PAP levels were higher in the cell salvage group, although not significantly (T0: 253 ± 251 ng/mL vs 168 ± 96 ng/mL; p: NS; T1: 95 ± 60 ng/mL vs 53 ± 32 ng/mL; p: NS). No differences were found for PAI-1, IL-6, heparin levels or for red blood cell (RBC) transfusions. The cell salvage group of patients had increased chest tube drainage (749 ± 320 vs 592 ± 264; p: NS) and fresh frozen plasma transfusion rate (5 (29%) pts vs 0 pts; p<0.04). Pump blood salvage with a cell saving system improved postoperative hemoglobin levels, but induced a strong thrombin generation, fibrinolysis activation and lower fibrinolysis inhibition. These conditions could generate a consumption coagulopathy.

Impact of blood product transfusion on short and long-term survival after cardiac surgery: more evidence

BACKGROUND

Despite the proven benefits in hemorrhagic shock, blood transfusions have been linked to increased morbidity and mortality. The short-term adverse effects of blood transfusion in cardiac surgical patients are well documented but there are very few studies that adequately assess the long-term survival. This study was undertaken to evaluate the effects of transfusion on both short-term and long-term survival after cardiac surgery.

METHODS

Data from 5,342 patients who underwent a cardiac surgical procedure from January 2002 to December 2005 at our institution were reviewed. The effect of transfusion of packed red blood cells (PRBC) and other blood products was tested in a 2-level approach of transfusion (any) versus no transfusion, and also a 4-level approach of transfusion (PRBC, other blood products, and both blood and blood products) versus no transfusion. Long-term survival data of these patients were obtained. Cox proportional hazard models, Kaplan-Meier survival plots, and hazard functions were used to compare the groups.

RESULTS

A total of 3,013 of the 5,342 study patients (56.4%) received transfusion during or within 72 hours of their cardiac surgery. Median time to death was significantly lower for patients who received transfusions; 1.15 years for PRC and 0.83 years for any transfusion, compared with 4.68 years in the non-transfused group. The overall 30-day mortality was 1.7%, but in patients who received transfusions (3.6%) was significantly higher than the non-transfused group (0.3%, p<0.001). The 1-year mortality (overall 3.9%) in the transfused group (7.3%, p<0.001) was also significantly higher than that in the non-transfused group (1.3%). The 5-year mortality rate in the transfused group was more than double that in the non-transfused group (16% vs 7%). After correction for comorbidities and other factors, transfusion was still associated with a 66% increase in mortality.

CONCLUSIONS

This study suggests that blood or blood product transfusion during or after cardiac surgery is associated with increased short-term and long-term mortality. It reinforces the need for prospective randomized controlled studies for evaluation of restrictive transfusion triggers and objective clinical indicators for transfusion in the cardiac surgical patient population.

Impact of major bleeding and blood transfusions after cardiac surgery: analysis from the Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) trial

BACKGROUND

Prior retrospective studies have identified a relationship between bleeding after cardiac surgery and subsequent mortality. Whether this is attributable to bleeding, anemia, or transfusions is undetermined.

METHODS

ACUITY was an international prospective trial of patients with acute coronary syndromes. Coronary artery bypass grafting (CABG) before hospital discharge was performed in 1,491 patients. Major bleeding was adjudicated as CABG- or non-CABG related. The relationship between CABG-related bleeding and 1-year mortality was determined using a time-updated covariate-adjusted Cox model.

RESULTS

Coronary artery bypass grafting-related major bleeding after surgery occurred in 789 patients (52.9%); allogeneic blood product transfusions were administered in 612 patients (41.0%), including red blood cell (RBC) transfusions in 570 (38.2%, range 1-53 U), platelet transfusions in 180 (12.1%), and fresh-frozen plasma in 195 (13.1%). One-year mortality occurred in 95 patients (6.4%). Red blood cell transfusion (but not transfusion of platelets or fresh-frozen plasma, CABG-related major bleeding per se, or nadir hemoglobin) was an independent predictor of 1-year mortality, but only after transfusion of ≥4 U (adjusted hazard ratio for death after transfusion of 1-3, 4-6, and ≥7 RBC units = 0.74, 2.01, and 5.22, respectively). Of the 95 deaths after CABG, 23 (24.2%) were attributable to CABG-related RBC transfusions.

CONCLUSIONS

In patients with acute coronary syndromes, RBC transfusion of ≥4 U after CABG is strongly associated with subsequent mortality. Future strategies should focus on reducing major hemorrhagic complications and RBC transfusions after CABG.

Rationale and design of the coronary artery bypass grafting surgery off or on pump revascularization study: a large international randomized trial in cardiac surgery

BACKGROUND

Uncertainty remains regarding the benefits and risks of the technique of operating on a beating heart (off pump) for coronary artery bypass grafting (CABG) surgery versus on-pump CABG. Prior trials had few events and relatively short follow-up. There is a need for a large randomized, controlled trial with long-term follow-up to inform both the short- and long-term impact of the 2 approaches to CABG.

METHODS

We plan to randomize 4,700 patients in whom CABG is planned to undergo the procedure on pump or off pump. The coprimary outcomes are a composite of total mortality, myocardial infarction (MI), stroke, and renal failure at 30 days and a composite of total mortality, MI, stroke, renal failure, and repeat revascularization at 5 years. We will also undertake a cost-effectiveness analysis at 30 days and 5 years after CABG surgery. Other outcomes include neurocognitive dysfunction, recurrence of angina, cardiovascular mortality, blood transfusions, and quality of life.

RESULTS

As of May 3, 2011, CORONARY has recruited >3,884 patients from 79 centers in 19 countries. Currently, patient's mean age is 67.6 years, 80.7% are men, 47.0% have a history of diabetes, 51.4% have a history of smoking, and 34.4% had a previous MI. In addition, 20.9% of patients have a left main disease, and 96.6% have double or triple vessel disease.

CONCLUSIONS

CORONARY is the largest trial yet conducted comparing off-pump CABG to on-pump CABG. Its results will lead to a better understanding of the safety and efficacy of off-pump CABG.

Red blood cell transfusion practice in patients presenting with acute upper gastrointestinal bleeding: a survey of 815 UK clinicians

BACKGROUND

Acute upper gastrointestinal bleeding (AUGIB) accounts for 14% of all red blood cell (RBC) transfusions in the United Kingdom, despite little evidence to guide optimal blood transfusion strategies and few data on the variation in practice. We aimed to survey UK clinicians about their RBC transfusion practice in AUGIB.

STUDY DESIGN AND METHODS

A survey describing six clinical vignettes of AUGIB was sent to practicing gastroenterologists, acute care physicians, and upper gastrointestinal surgeons. Respondents were asked to select a hemoglobin (Hb) trigger at which they would ordinarily transfuse RBCs.

RESULTS

The response rate was 48% (815/1709). Transfusion triggers differed significantly between all six cases (p < 0.001). There was significant variation in the selected Hb trigger between different clinical specialties for five of the six scenarios. Surgeons were more likely to select a lower Hb transfusion trigger than physicians across all six scenarios (p < 0.005), as were clinicians who had graduated more recently (p < 0.05 for Scenarios 1-3). The responses suggested the belief that restrictive use of RBCs is appropriate, which is in part discordant with actual observed practice. Only 70% of respondents reported familiarity with national guidelines for AUGIB.

CONCLUSIONS

There is significant variation in the reported approach to transfusion practice among clinicians caring for patients with AUGIB, with both patient- and clinician-related factors accounting for these differences. Further studies are needed to evaluate the safety and efficacy of differing blood transfusion strategies in patients presenting with AUGIB.

Perioperative blood transfusion practices in oncologic thoracic surgery: when, why, and how

INTRODUCTION

Available information on perioperative blood transfusion practices in oncologic thoracic surgery is scant and outdated. The purpose of this study was to investigate transfusion requirements in patients undergoing curative resection for lung cancer and to identify possible factors predictive of perioperative blood transfusion in our cohort of patients.

METHODS

From 1st January 2009 to 31st December 2009, 317 patients underwent anatomic pulmonary resection. Patients who received at least 1 unit of red blood cells comprised the "transfused" group. Each case in this group was matched for surgical procedure with a control subject who did not require blood transfusion and was operated on during the same year; these patients comprised the "not transfused" group.

RESULTS

A total of 75 patients (23.6%) received at least 1 unit of red blood cells during the perioperative period. Factors conditioning perioperative blood transfusion were: preoperative hemoglobin level (p < 0.0001); procedure duration (p = 0.017); body mass index (p < 0.001); induction therapies (p = 0.017); redo procedure (p = 0.021). Age, sex, histology, stage, ASA score, side, intraoperative blood loss, and fluid infusion did not affect perioperative blood transfusion practices.

CONCLUSIONS

Preoperative hemoglobin level is the major risk factor for perioperative blood transfusion practices in oncologic thoracic surgery; procedure duration, body mass index, induction therapies, and redo procedure may condition transfusional needs, although they were actually not predictive on multivariate analysis.

The golden age of minimally invasive cardiothoracic surgery: current and future perspectives

Over the past decade, minimally invasive cardiothoracic surgery (MICS) has grown in popularity. This growth has been driven, in part, by a desire to translate many of the observed benefits of minimal access surgery, such as decreased pain and reduced surgical trauma, to the cardiac surgical arena. Initial enthusiasm for MICS was tempered by concerns over reduced surgical exposure in highly complex operations and the potential for prolonged operative times and patient safety. With innovations in perfusion techniques, refinement of transthoracic echocardiography and the development of specialized surgical instruments and robotic technology, cardiac surgery was provided with the necessary tools to progress to less invasive approaches. However, much of the early literature on MICS focused on technical reports or small case series. The safety and feasibility of MICS have been demonstrated, yet questions remain regarding the relative efficacy of MICS over traditional sternotomy approaches. Recently, there has been a growth in the body of published literature on MICS long-term outcomes, with most reports suggesting that major cardiac operations that have traditionally been performed through a median sternotomy can be performed through a variety of minimally invasive approaches with equivalent safety and durability. In this article, we examine the technological advancements that have made MICS possible and provide an update on the major areas of cardiac surgery where MICS has demonstrated the most growth, with consideration of current and future directions.

Do miniaturized extracorporeal circuits confer significant clinical benefit without compromising safety? A meta-analysis of randomized controlled trials

Miniaturized extracorporeal circulation (mECC) attempts to reduce the adverse effects of conventional extracorporeal circulation (CECC) bypass. However, the potential benefits remain unclear and safety concerns persist. A systematic literature review identified 29 studies incorporating 2,355 patients: 1,181 (50.1%) who underwent cardiac surgery with CECC and 1,174 (49.9%) with mECC. These were meta-analyzed using random effects modeling. Heterogeneity, subgroup analysis, and risk of bias were assessed. Primary endpoints were 30-day mortality, neurovascular compromise, and end organ dysfunction. Secondary endpoints were length of stay and transfusion burden. Miniaturized extracorporeal circulation significantly reduced postoperative arrhythmias (p = 0.03), but no significant difference in 30-day mortality, neurocognitive disturbance, cerebrovascular events, renal failure, or myocardial infarction was identified. Miniaturized extracorporeal circulation also significantly reduced mean blood loss (p < 0.00001) and number of patients transfused (p < 0.00001); however, duration of hospitalization, units transfused per patient, chest tube drainage, and revision for rebleeding remained unchanged. Subgroup analysis of larger studies (10 studies, n ≥ 31) showed mECC to significantly reduce ventilation period, hospital stay, and intensive care unit (ICU) stay. Similarly, a significant reduction in neurocognitive disturbance was seen in studies with closely matched demographic groups. Miniaturized extracorporeal circulation is not associated with increased cerebrovascular injury and may confer an advantage, reducing postoperative arrhythmia, blood loss, and transfusion burden.

The incidence, risk factors, and outcome of transfusion-related acute lung injury in a cohort of cardiac surgery patients: a prospective nested case-control study

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality. Both antibodies and bioactive lipids that have accumulated during storage of blood have been implicated in TRALI pathogenesis. In a single-center, nested, case-control study, patients were prospectively observed for onset of TRALI according to the consensus definition. Of 668 patients, 16 patients (2.4%) developed TRALI. Patient-related risk factors for onset of TRALI were age and time on the cardiopulmonary bypass. Transfusion-related risk factors were total amount of blood products (odds ratio [OR] = 1.2; 95% confidence interval [CI], 1.03-1.44), number of red blood cells stored more than 14 days (OR = 1.6; 95% CI, 1.04-2.37), total amount of plasma (OR = 1.2; 95% CI, 1.03-1.44), presence of antibodies in donor plasma (OR = 8.8; 95% CI, 1.8-44), and total amount of transfused bioactive lipids (OR = 1.0; 95% CI, 1.00-1.07). When adjusted for patient risk factors, only the presence of antibodies in the associated blood products remained a risk factor for TRALI (OR = 14.2; 95% CI, 1.5-132). In-hospital mortality of TRALI was 13% compared with 0% and 3% in transfused and nontransfused patients, respectively (P < .05). In conclusion, the incidence of TRALI is high in cardiac surgery patients and associated with adverse outcome. Our results suggest that cardiac surgery patients may benefit from exclusion of blood products containing HLA/HNA antibodies.

Assessment of thrombin generation measured before and after cardiopulmonary bypass surgery and its association with postoperative bleeding

BACKGROUND

Bleeding after cardiopulmonary bypass (CPB) is a major cause of morbidity and mortality and consumes large amounts of blood. Identifying patients at increased risk of bleeding secondary to hemostatic impairment may improve clinical outcomes by allowing early intervention.

METHODS

This present study recruited 77 patients undergoing CPB and measured coagulation screens, coagulation factors, TEG(®), Rotem(®) and thrombin generation (TG) before surgery and 30 min after heparin reversal. The tests were analyzed to investigate whether they identified patients at increased risk of excess bleeding (defined as > 1000 mL) in the first 24 h postoperatively.

RESULTS

Patients who bled > 1000 mL had a lower: platelet count (P < 0.02), factors (F)IX, X and XI (P < 0.005), endogenous thrombin potential (ETP) and an initial rate of TG (P < 0.02) and higher activated partial thromboplastin time (aPTT) (P < 0.001) than patients who bled < 1000 mL. Receiver operating characteristic (ROC) analysis was significant for post-operative TG and aPTT (P < 0.001). Furthermore, reduced pre-operative TG was associated with increased postoperative bleeding (P < 0.02). Pre- and postoperative TG were correlated (ρ = 0.7, P < 0.001). TEG(®), Rotem(®) and prothrombin time (PT) at either time point were not associated with increased bleeding.

CONCLUSION

These data suggest that pre-operative defects in the propagation phase of hemostasis are exacerbated during CPB, contributing to bleeding post-CPB. TG taken both pre- and postoperatively could potentially be used to identify patients at an increased risk of bleeding post-CPB.

Blood conservation in cardiac surgery

Cardiac surgery is one of the largest users of blood and blood products--currently estimated at 15% of U.K. blood stocks. While the blood supply could be considered to be the safest it has ever been, there are well recognised risks associated with the transfusion of red cells and blood products. It is appropriate that attempts should be made to decrease and optimise the transfusion of blood and blood products.

Survival and length of stay following blood transfusion in octogenarians following cardiac surgery

Our aim was to assess if peri-operative blood transfusion is an independent risk factor for mortality and morbidity in the elderly. We report the results of a cohort study of all patients aged 80 or more on the day of their emergency or elective cardiac surgery (n = 874), using routinely collected data from January 2003 to November 2007. The primary outcome was all-cause mortality in hospital. The secondary outcomes were duration of stay in the intensive care unit (ICU) and overall hospital stay. Confounding variables were used to build up a risk model using a multivariable logistic regression analysis, and blood transfusion was added to assess whether it had additional predictive value for hospital mortality. Patients were divided into three groups: (i) transfusion of 0-2 units of red blood cells; (ii) transfusion of > 2 units of red blood cells and (iii) transfusion of red blood cells plus other clotting products. The strongest independent predictors of hospital death were logistic EuroSCORE and body mass index. After inclusion of these two variables, the odds ratio for transfusion remained significant. Relative to 0-2 units, the odds ratio for > 2 units was 6.80 (95% CI 2.46-18.8), and for other additional blood products was 14.4 (95% CI 5.34-37.3), with a p value of < 0.001. Duration of stay in the ICU was significantly associated with the amount of blood products administered (median (IQR [range]) ICU stay 1 (1-2 [0-15]) day if transfused 0-2 units of red blood cells, 2 (1-6 [0-128]) days if transfused > 2 units of red blood cells and 3 (1-76 [0-114]) days if other clotting products were used; p value < 0.001). Hospital stay was also associated with the amount of red cells used (p < 0.001).

Intra-operative intravenous fluid restriction reduces perioperative red blood cell transfusion in elective cardiac surgery, especially in transfusion-prone patients: a prospective, randomized controlled trial

BACKGROUND

Cardiac surgery is a major consumer of blood products, and hemodilution increases transfusion requirements during cardiac surgery under CPB. As intraoperative parenteral fluids contribute to hemodilution, we evaluated the hypothesis that intraoperative fluid restriction reduces packed red-cell (PRC) use, especially in transfusion-prone adults undergoing elective cardiac surgery.

METHODS

192 patients were randomly assigned to restrictive (group A, 100 pts), or liberal (group B, 92 pts) intraoperative intravenous fluid administration. All operations were conducted by the same team (same surgeon and perfusionist). After anesthesia induction, intravenous fluids were turned off in Group A (fluid restriction) patients, who only received fluids if directed by protocol. In contrast, intravenous fluid administration was unrestricted in group B. Transfusion decisions were made by the attending anesthesiologist, based on identical transfusion guidelines for both groups.

RESULTS

137 of 192 patients received 289 PRC units in total. Age, sex, weight, height, BMI, BSA, LVEF, CPB duration and surgery duration did not differ between groups. Fluid balance was less positive in Group A. Fewer group A patients (62/100) required transfusion compared to group B (75/92, p < 0.04). Group A patients received fewer PRC units (113) compared to group B (176; p < 0.0001). Intraoperatively, the number of transfused units and transfused patients was lower in group A (31 u in 19 pts vs. 111 u in 62 pts; p < 0.001). Transfusions in ICU did not differ significantly between groups. Transfused patients had higher age, lower weight, height, BSA and preoperative hematocrit, but no difference in BMI or discharge hematocrit. Group B (p < 0.005) and female gender (p < 0.001) were associated with higher transfusion probability. Logistic regression identified group and preoperative hematocrit as significant predictors of transfusion.

CONCLUSIONS

Our data suggest that fluid restriction reduces intraoperative PRC transfusions without significantly increasing postoperative transfusions in cardiac surgery; this effect is more pronounced in transfusion-prone patients.

TRIAL REGISTRATION

NCT00600704, at the United States National Institutes of Health.

The effect of acute autologous blood transfusion on coagulation dysfunction after cardiopulmonary bypass

OBJECTIVE

To evaluate the influence of acute autologous blood transfusion on postcardiopulmonary bypass coagulation disturbances evaluated by thromboelastography (TEG) as a point-of-care test.

METHODS

This prospective randomized controlled study included consecutive patients who underwent elective cardiac surgery with cardiopulmonary bypass. The patients in group A underwent acute autologous blood transfusion with acute normovolemic haemodilution and those in group H received homologous blood, if needed, and served as controls.

RESULTS

A total of 62 patients, from 68 enrolled, completed the study: 27 in group A and 35 in group H. Both groups had similar prolongation of prothrombin time and partial thromboplastin time, decreased platelets count and changes in postoperative thromboelastographic variables. There were no differences between them for postoperative bleeding, blood transfusions or haemoglobin values. There was significant prolongation of the R value of TEG (without heparinase) in both groups at 4 h after surgery compared with the immediate postoperative values: from 11.3 +/- 4.2 to 12.3 +/- 5.5 mm, P < 0.05 for group A and from 9.9 +/- 3.7 to 12.5 +/- 5.4 mm, P < 0.01 for group H. The R values of TEG with and without heparinase differed significantly (P < 0.05) at 4 h postoperatively.

CONCLUSION

Autologous blood transfusion of 15% estimated blood volume did not affect postcardiopulmonary bypass coagulopathy, nor did it decrease blood loss or homologous blood and its products transfusion in the early postoperative period. TEG is a valuable measure for detecting coagulation dysfunction with a potential role in the postoperative management of cardiac patients.

Clinical guidelines and off-license recombinant activated factor VII: content, use, and association with patient outcomes

BACKGROUND

Recombinant activated factor VII (rFVIIa) is increasingly being used off-license for treating critical bleeding. Guidelines may therefore be useful for improving processes and outcomes. Little is known regarding guidelines for off-license rFVIIa or their association with patient outcomes.

OBJECTIVES

To investigate the availability of hospital guidelines for off-license rFVIIa use and the association between these guidelines and mortality.

METHODS

Data were extracted from the Haemostasis Registry, which collects all cases of off-license rFVIIa use in participating institutions in Australia and New Zealand. Contributing hospitals were requested to supply a copy of the institutional guideline relating to off-license rFVIIa administration. The characteristics of patients treated in accordance with all elements of the guidelines were compared with those of patients for who one or more guideline elements had been violated. The relationship between guideline-directed treatment and 28-day mortality was investigated using stepwise logistic regression.

RESULTS

Two thousand five hundred and fifty-one patients in 75 hospitals were available for analysis. Of these hospitals, 58 provided a guideline for analysis. Patients complying with all guideline elements (n = 530) did not differ from patients receiving care that violated guidelines (n = 1035) regarding age, size of dose, or gender. Guideline-directed treatment was not found to have an association with 28-day mortality following logistic regression.

CONCLUSIONS

Few patients are treated in accordance with the criteria of rFVIIa guidelines, despite their availability in the majority of hospitals. Moreover, 28-day mortality does not appear to be associated with the use of guidelines in this patient group. Refinement of guidelines relating to the off-license use of rFVIIa is therefore required.