Changes in blood coagulation during and following cardiopulmonary bypass: lack of correlation with clinical bleeding

Bleeding is associated with severely impaired outcomes in surgery for acute type a aortic dissection

Background. Surgery for acute type A aortic dissection confers a risk for significant bleeding. We analyzed the impact of massive bleeding on complications after surgery for acute type A aortic dissection. Methods. Patients undergoing surgery for acute type A aortic dissection from the retrospective multicenter Nordic Consortium for Acute Type A Aortic Dissection (NORCAAD) database 2005-2014 were eligible. Massive bleeding was defined according to the Universal Definition of Perioperative Bleeding. The primary outcome measure was early mortality and secondary outcome measures were perioperative stroke, mechanical ventilation more than 48 h, new-onset dialysis, and intensive care unit stay. Propensity score matching was performed to adjust for differences in covariates. Results. Nine hundred ninety-seven patients were included, of whom 403 (40.4%) had massive bleeding. In the propensity score-matched cohort (344 pairs), patients with massive bleeding had higher 30-day mortality (17.2 versus 7.6%, p < .001), mechanical ventilation more than 48 h (52.8 versus 22.6%, p < .001), perioperative stroke (24.3 versus 14.8%, p = .002), new-onset dialysis (22.5 versus 4.9%, p < .001), and longer intensive care unit stay (6 versus 3 days, p < .001), compared with patients without massive bleeding. Risk factors for massive bleeding were previous cardiac surgery, preoperative clopidogrel or ticagrelor therapy, DeBakey type I dissection, and localized or generalized malperfusion. Conclusions. Massive bleeding in surgery for acute type A aortic dissection is associated with a markedly increased risk for severe complications as well as early death. Further improvement of surgical technique and pharmacological optimization of coagulation is paramount to possibly improve outcomes in acute type A aortic dissection repair.

Biomarkers of inflammation and coagulation after minimally invasive mitral valve surgery: a prospective comparison to conventional surgery

OBJECTIVES

Minimally invasive cardiac surgery techniques are increasingly used but have longer cardiopulmonary bypass time, which may increase inflammatory response and negatively affect coagulation. Our aim was to compare biomarkers of inflammation and coagulation as well as transfusion rates after minimally invasive mitral valve repair and mitral valve surgery using conventional sternotomy.

DESIGN

A prospective non-randomized study was performed enrolling 71 patients undergoing mitral valve surgery (35 right mini-thoracotomy and 36 conventional sternotomy procedures). Blood samples were collected pre- and postoperatively to assess inflammatory response. Thromboelastometry (ROTEM) was performed to assess coagulation, and transfusion rates were monitored.

RESULTS

The minimally invasive group had longer cardiopulmonary bypass times compared to the sternotomy group: 127 min ([115-146] vs 79 min [65-112], p < 0.001) and were cooled to a lower temperature during cardiopulmonary bypass, 34 °C vs 36 °C (p = 0.04). IL-6 was lower in the minimally invasive group compared to the conventional sternotomy group when measured at the end of the surgical procedure, (38 [23-69] vs 61[41-139], p = 0.008), but no differences were found at postoperative day 1 or postoperative day 3. The transfusion rate was lower in the minimally invasive group (14%) compared to full sternotomy (35%, p = 0.04) and the chest tube output was reduced, (395 ml [190-705] vs 570 ml [400-1040], p = 0.04).

CONCLUSIONS

Our data showed that despite the longer use of extra corporal circulation during surgery, minimally invasive mitral valve repair is associated with reduced inflammatory response, lower rates of transfusion, and reduced chest tube output.

Influence of vascular graft type for ascending aorta replacement on the early postoperative outcome

BACKGROUND

Aim of this study was to find out if the type of vascular prosthesis used, especially collagen impregnated polyester versus gelatin impregnated woven fabric graft, has any impact on the early postoperative bleeding rate, blood product consumption and re-thoracotomy rate in isolated ascending aortic surgery.

METHODS

n = 46 consecutive patients who received a supra-commissural replacement of the ascending aorta between 01/2016 - 01/ 2021 were included in this retrospective single-center study. The underlying pathology was an aortic aneurysm in 36 (81 %) and/or an acute type A aortic dissection (ATAAD) limited to the ascending aorta in 7 (15 %) and/or a penetrating aortic ulcer (PAU) with intramural hematoma in 6 (13 %) patients. According to the type of vascular graft used, the cohort was divided as follows: 25 patients (54%) received a double velour woven, collagen impregnated polyester graft (Hemashield, Getinge; CI-Group) whereas in 21 patients (46 %) a gelatin impregnated woven fabric graft was used (Gelweave, Vascutek / Terumo; GI-group). As primary endpoints class 3 bleeding according to the Valve Academic Research Consortium (VARC3) criteria and freedom from re-intervention were assessed. As secondary endpoints, 30-day mortality and stroke were defined.

RESULTS

Preoperative risk assessment (EuroSCORE II), gender-, BMI-stratification and NYHA-classification as well as mean CPB-times (114 ± 44 min vs 110 ± 48 min) and aortic cross-clamp times (71 ± 28 min vs 66 ± 30 min) were similar in both groups. Bleeding, measured by drainage volume output within the first postoperative 24 h (480 ± 426 mL vs 389 ± 169 mL), erythrocytes concentrate consumption (2,4 vs 2,3) and similar re-thoracotomy rates (4 vs 4.7 %) showed no difference between groups. 30- day mortality (12 vs 5 %; p = 0.614) and stroke rates (4 vs 9.5; p = 0,4) showed no differences between groups.

CONCLUSIONS

Regarding postoperative bleeding no difference were seen between the two graft types. Long-term follow-up and larger prospective randomized studies are requested to prove these findings.

Coagulation Tests and Bleeding Classification After Cardiopulmonary Bypass: A Prospective Study

OBJECTIVE

No recent prospective studies have analyzed the accuracy of standard coagulation tests and thromboelastography (TEG) to identify patients with excessive microvascular bleeding following cardiopulmonary bypass (CPB). The aim of this study was to assess the value of coagulation profile tests, as well as TEG, for the classification of microvascular bleeding after CPB.

DESIGN

A prospective observational study.

SETTING

At a single-center academic hospital.

PARTICIPANTS

Patients ≥18 years of age undergoing elective cardiac surgery.

INTERVENTIONS

Qualitative assessment of microvascular bleeding post-CPB (surgeon and anesthesiologist consensus) and the association with coagulation profile tests and TEG values.

MEASUREMENTS AND MAIN RESULTS

A total of 816 patients were included in the study-358 (44%) bleeders and 458 (56%) nonbleeders. Accuracy, sensitivity, and specificity for the coagulation profile tests and TEG values ranged from 45% to 72%. The predictive utility was similar across tests, with prothrombin time (PT) (62% accuracy, 51% sensitivity, 70% specificity), international normalized ratio (INR) (62% accuracy, 48% sensitivity, 72% specificity), and platelet count (62% accuracy, 62% sensitivity, 61% specificity) displaying the highest performance. Secondary outcomes were worse in bleeders versus nonbleeders, including higher chest tube drainage, total blood loss, transfusion of red blood cells, reoperation rates (p < 0.001, respectively), readmission within 30 days (p = 0.007), and hospital mortality (p = 0.021).

CONCLUSIONS

Standard coagulation tests and individual components of TEG in isolation agree poorly with the visual classification of microvascular bleeding after CPB. The PT-INR and platelet count performed best but had low accuracy. Further work is warranted to identify better testing strategies to guide perioperative transfusion decisions in cardiac surgical patients.

Outcomes of Heart Transplantation Using a Temperature-controlled Hypothermic Storage System

BACKGROUND

The SherpaPak Cardiac Transport System is a novel technology that provides stable, optimal hypothermic control during organ transport. The objectives of this study were to describe our experience using the SherpaPak system and to compare outcomes after heart transplantation after using SherpaPak versus the conventional static cold storage method (non-SherpaPak).

METHODS

From 2018 to June 2021, 62 SherpaPak and 186 non-SherpaPak patients underwent primary heart transplantation at Stanford University with follow-up through May 2022. The primary end point was all-cause mortality, and secondary end points were postoperative complications. Optimal variable ratio matching, cox proportional hazards regression model, and Kaplan-Meier survival analyses were performed.

RESULTS

Before matching, the SherpaPak versus non-SherpaPak patients were older and received organs with significantly longer total allograft ischemic time. After matching, SherpaPak patients required fewer units of blood product for perioperative transfusion compared with non-SherpaPak patients but otherwise had similar postoperative outcomes such as hospital length of stay, primary graft dysfunction, inotrope score, mechanical circulatory support use, cerebral vascular accident, myocardial infarction, respiratory failure, new renal failure requiring dialysis, postoperative bleeding or tamponade requiring reoperation, infection, and survival.

CONCLUSIONS

In conclusion, this is one of the first retrospective comparison studies that evaluated the outcomes of heart transplantation using organs preserved and transported via the SherpaPak system. Given the excellent outcomes, despite prolonged total allograft ischemic time, it may be reasonable to adopt the SherpaPak system to accept organs from a remote location to further expand the donor pool.

Preoperative clinical application of human fibrinogen in patients with acute Stanford type A aortic dissection: A single-center retrospective study

OBJECTIVE

To evaluate the perioperative clinical efficacy of preoperative human fibrinogen treatment in patients with acute Stanford type A aortic dissection (ATAAD).

METHODS

Data of 159 patients with ATAAD who underwent emergency surgical treatment in our hospital from January 2019 to December 2020 were retrospectively analyzed. Patients were divided into two groups according to whether human fibrinogen was administered before surgery: patients in group A received fibrinogen before surgery, while those in group B did not. The preoperative clinical data, surgical data, postoperative data, complications related to the coagulation function, and mortality of the two groups were compared and analyzed.

RESULTS

The in-hospital mortality was similar in the two groups (2.9% vs. 9.3%, p = .122). However, group A had a significantly shorter operation time (279.24 ± 39.03 vs. 298.24 ± 45.90, p = .008), lower intraoperative blood loss (240.48 ± 96.75 vs. 353.70 ± 189.80, p < .001), and reduced intraoperative transfusion requirement of red blood cells (2.61 ± 1.18 vs. 6.05 ± 1.86, p < .001). The postoperative suction drainage within 24 h in group A was significantly decreased (243.24 ± 201.52 vs. 504.22 ± 341.08, p = .002). The incidence of postoperative acute kidney injury (AKI) in group A was lower than that in group B (3.8% vs. 14.8%, p = .023). Similarly, the incidence of postoperative hepatic insufficiency in group A was lower than that in group B (1.9% vs. 9.3%, p = .045). In group A, the mechanical ventilation time was shorter (47.68 ± 28.61 vs. 118.21 ± 173.16, p = .004) along with reduced intensive care unit stay time (4.06 ± 1.18 vs. 8.09 ± 9.42, p = .003), and postoperative hospitalization days (19.20 ± 14.60 vs. 23.50 ± 7.56, p = .004).

CONCLUSION

Preoperative administration of human fibrinogen in patients undergoing ATAAD surgery can effectively reduce the intraoperative blood loss, amount of blood transfused, operation time, and postoperative complications, and improve the early prognosis of patients. In addition, this procedure is highly safe.

Clinical application of viscoelastic point-of-care tests of coagulation-shifting paradigms

Bleeding during cardiac surgery, liver transplant, trauma and post partum hemorrhage are often multifactorial and these factors are dynamic as new factors crop up during the course of management. Conventional tests of coagulation offer information of a part of the coagulation system and also is time consuming. Viscoelastic point of care tests (VE POCTs) like rotational thromboelastometry, thromboelastogram and Sonoclot, are based on analysis of the viscoelastic properties of clotting blood and provide information for the entire coagulation pathway. In this comprehensive review being presented here, we have examined the pros and cons of VE POCTs including clinical, cost and survival benefits. The recommendations of the various guidelines regarding use of VE POCTs in various scenarios have been discussed. The review also tried to offer suggestions as to their optimal role in management of bleeding during cardiac surgeries, extracorporeal membrane oxygenation, left ventricular assist devices, liver transplant and briefly in trauma and postpartum hemorrhage.

Role of Using a Thromboelastometry-Based Protocol for Transfusion Management in Combined Coronary Artery Bypass Grafting and Valve Surgery: A Randomized Clinical Trail

The aim of this study was to evaluate the impact of using a thromboelastometry-based protocol on transfusion requirements in patients undergoing combined coronary artery bypass grafting (CABG) and valve surgery. 80 adult patients scheduled for elective combined CABG and valve surgery were included in this clinical trial study. Patients were randomly allocated to the thromboelastometry (ROTEM) (n = 40) or control groups (n = 40). In the ROTEM group, transfusion was directed according to a thromboelastometry-based protocol. In the control group, transfusion was conducted according to the routine practices including conventional coagulation testing and clinical judgments. Finally, transfusion requirements were compared between groups. Use of thromboelastometry- based protocol resulted in 67% reduction in blood products units' consumption as well as 23% in the percentage of patients transfused. This reduction was especially evident in relation to fresh frozen plasma (FFP) and platelet consumption. No significant differences were found both in the percentage of patients receiving RBC and number of transfused RBC units. Using thromboelastometry tests incorporated a protocol results in reduction of transfusion requirements in patients undergoing elective combined CABG and valve surgery.

Comparison of standard coagulation testing with thromboelastometry tests in cardiac surgery

Introduction: According to the several evidences, using thromboelastometry as a point of care test can be effective in reduction in blood loss and transfusion requirements in cardiac surgeries. However, there are limited data regarding to the comparison of thromboelastometry and the standard coagulation tests. In this study, we compared thromboelastometry and standard coagulation tests (PT, PTT and fibrinogen level) in patients under combined coronary-valve surgery. Methods: Forty adult patients who were under on-pump combined coronary-valve surgery were included in this study. Thromboelastometry tests Fibtem, Intem, Extem and Heptem), along with standard coagulation tests (PT, PTT and fibrinogen assay) were simultaneously performed in two time points, before and after the pump (pre-CPB and post-CPB, respectively). Results: A total of 80 blood samples were analyzed. There were no significant correlation between PT test and the CT-Extem parameter as well as PTT and CT-Intem parameter either in pre-CPB and post-CPB (P >0.05). On the contrary, fibrinogen level had high correlation with A10-Fibtem and A10-Extem in pre-PCB (P <0.05). 82% of PT and 84% of PTT measurements were outside the reference range, while abnormal CT in Extem and Intem was observed in 17.9%. Conclusion: For management of bleeding, adequate perioperative haemostatic monitoring is indispensable during cardiac surgery. Standard coagulation tests are time consuming and cannot be interchangeably used with thromboelastomety and relying on their results to decide whether blood transfusion is necessary, leads to the inappropriate transfusion.

Acute type A aortic dissection - a review

Acute type A aortic dissection (ATAAD) is still one of the most challenging diseases that cardiac surgeons encounter. This review is based on the current literature and includes the results from the Nordic Consortium for Acute Type-A Aortic Dissection (NORCAAD) database. It covers different aspects of ATAAD and concentrates on the outcome of surgical repair. The diagnosis is occasionally delayed, and ATAAD is usually lethal if prompt repair is not performed. The dynamic nature of the disease, the variation in presentation and clinical course, and the urgency of treatment require significant attentiveness. Many surgical techniques and perfusion strategies of varying complexity have been described, ranging from simple interposition graft to total arch replacement with frozen elephant trunk and valve-sparing root reconstruction. Although more complex techniques may provide long-term benefit in selected patients, they require significant surgical expertise and experience. Short-term survival is first priority so an expedited operation that fits in with the surgeon's level of expertise is in most cases appropriate.

Role of Thromboelastography and Rotational Thromboelastometry in the Management of Cardiovascular Diseases

The monitoring of coagulation by viscoelastometric methods—thromboelastography and rotational thromboelastometry—may detect the contributions of cellular and plasma components of hemostasis. These methods might overcome some of the serious limitations of conventional laboratory tests. Viscoelastic testing can be repeatedly performed during and after surgery and thus provides a dynamic picture of the coagulation process during these periods. Several experiences with the use of these methods in cardiovascular surgery have been reported, but there is perspective for more frequent use of these assays in the assessment of platelet response to antiplatelet therapy and in the assessment of coagulation in patients on long-term dabigatran therapy. This article reviews the current role and future perspectives of thromboelastography and thromboelastometry in the management of cardiovascular diseases.

Diagnostic and therapeutic medical devices for safer blood management in cardiac surgery: systematic reviews, observational studies and randomised controlled trials

Background

Anaemia, coagulopathic bleeding and transfusion are strongly associated with organ failure, sepsis and death following cardiac surgery.

Objective

To evaluate the clinical effectiveness and cost-effectiveness of medical devices used as diagnostic and therapeutic tools for the management of anaemia and bleeding in cardiac surgery.

Methods and results

Workstream 1 – in the COagulation and Platelet laboratory Testing in Cardiac surgery (COPTIC) study we demonstrated that risk assessment using baseline clinical factors predicted bleeding with a high degree of accuracy. The results from point-of-care (POC) platelet aggregometry or viscoelastometry tests or an expanded range of laboratory reference tests for coagulopathy did not improve predictive accuracy beyond that achieved with the clinical risk score alone. The routine use of POC tests was not cost-effective. A systematic review concluded that POC-based algorithms are not clinically effective. We developed two new clinical risk prediction scores for transfusion and bleeding that are available as e-calculators. Workstream 2 – in the PAtient-SPecific Oxygen monitoring to Reduce blood Transfusion during heart surgery (PASPORT) trial and a systematic review we demonstrated that personalised near-infrared spectroscopy-based algorithms for the optimisation of tissue oxygenation, or as indicators for red cell transfusion, were neither clinically effective nor cost-effective. Workstream 3 – in the REDWASH trial we failed to demonstrate a reduction in inflammation or organ injury in recipients of mechanically washed red cells compared with standard (unwashed) red cells.

Limitations

Existing studies evaluating the predictive accuracy or effectiveness of POC tests of coagulopathy or near-infrared spectroscopy were at high risk of bias. Interventions that alter red cell transfusion exposure, a common surrogate outcome in most trials, were not found to be clinically effective.

Conclusions

A systematic assessment of devices in clinical use as blood management adjuncts in cardiac surgery did not demonstrate clinical effectiveness or cost-effectiveness. The contribution of anaemia and coagulopathy to adverse clinical outcomes following cardiac surgery remains poorly understood. Further research to define the pathogenesis of these conditions may lead to more accurate diagnoses, more effective treatments and potentially improved clinical outcomes.

Study registration

Current Controlled Trials ISRCTN20778544 (COPTIC study) and PROSPERO CRD42016033831 (systematic review) (workstream 1); Current Controlled Trials ISRCTN23557269 (PASPORT trial) and PROSPERO CRD4201502769 (systematic review) (workstream 2); and Current Controlled Trials ISRCTN27076315 (REDWASH trial) (workstream 3).

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 5, No. 17. See the NIHR Journals Library website for further project information.

Predictors and impact of massive bleeding in acute type A aortic dissection

Objectives

Bleeding complications associated with acute type A aortic dissection (aTAAD) are a well-known clinical problem. Here, we evaluated predictors of massive bleeding related to aTAAD and associated surgery and assessed the impact of massive bleeding on complications and survival.

Methods

This retrospective study of 256 patients used Blood Conservation Using Antifibrinolytics in a Randomized Trial (BART) criteria to define massive bleeding, which was met by 66 individuals (Group I) who were compared to the remaining patients (Group II). Multivariable logistic regression was used to identify independent predictors of massive bleeding and in-hospital mortality, Kaplan-Meier estimates for analysis of late survival, and Cox regression analysis to evaluate independent predictors of late mortality.

Results

Independent predictors of massive bleeding included symptom duration (odds ratio [OR], 0.974 per hour increment; 95% confidence interval [CI], 0.950-0.999; P  =   0.041) and DeBakey type 1 dissection (OR, 2.652; 95% CI, 1.004-7.008; P  =   0.049). In-hospital mortality was higher in Group I (30.3% vs 8.0%, P  <0.001). Kaplan-Meier estimates of survival indicated poorer survival for Group I at 1, 3 and 5 years (68.8 ± 5.9% vs 92.8 ± 1.9%; 65.2 ± 6.2% vs 85.3 ± 2.7%; 53.9 ± 6.9% vs 82.1 ± 3.3 %, respectively; log rank P  <   0.001). Re-exploration for bleeding was an independent predictor of in-hospital (OR, 3.109; 95% CI, 1.044-9.256; P  =   0.042) and late mortalities (hazard ratio, 3.039; 95% CI, 1.605-5.757; P  =   0.001).

Conclusions

Massive bleeding in patients with aTAAD is prompted by shorter symptom duration and longer extent of dissection and has deleterious effects on outcomes of postoperative complications as well as in-hospital and late mortalities.

Optimal Management of Bleeding Complications After Cardiac Surgery

Patients undergoing cardiac surgery with cardiopulmo nary bypass (CPB) are at increased risk for excessive perioperative blood loss requiring transfusion of blood products. Point-of-care evaluation of platelets, coagu lation factors, and fibrinogen can enable physicians to assess bleeding abnormalities rapidly. They also can facilitate the optimal administration of pharmacologic and transfusion-based therapy and allow physicians to identify patients with surgical bleeding. The ability to reduce the unnecessary use of blood products in this setting has important implications for emerging issues in blood inventory and blood costs. The ability to de crease operative time along with re-exploration rates has important consequences for health care costs in an increasingly managed health care environment. Copyright© 2001 by W.B. Saunders Company.

The effects of intermittent prebypass heparin dosing in patients undergoing coronary artery bypass grafting

In this study, 10 patients (Group B) were given three consecutive prebypass doses of heparin (100 IU/kg) with a 4 min interval prior to cardiopulmonary bypass (CPB) institution. They were compared with 10 patients (Group A) receiving the standard single prebypass heparin dose (300 IU/kg). The haemostatic response and anticoagulant monitoring during the perioperative period were investigated by point-of-care and several coagulation tests. Results of both groups were also correlated to blood loss. Three patients in Group B required additional heparin during bypass as compared with six patients in Group A. This suggests that intermittent prebypass heparin dosing is more effective in maintaining adequate levels of anticoagulation during CPB. Group B had a lower mean decrease in factor VIII (13.9% versus 43.2%), fibrinogen (38.5% versus 46.6%), antithrombin III (34.7% versus 40.1%) and platelet count (23.2% versus 28.9%) during bypass while only one unit of red cell concentrate was required postoperatively as compared with four units in Group A. In one patient, high fibrinolytic assays were associated with a haemorrhagic pericardial effusion occurring beyond 24 hours postsurgery.

Postoperative Critical Care of the Adult Cardiac Surgical Patient. Part I: Routine Postoperative Care

OBJECTIVES

Cardiac surgery, including coronary artery bypass, cardiac valve, and aortic procedures, is among the most common surgical procedures performed in the United States. Successful outcomes after cardiac surgery depend on optimum postoperative critical care. The cardiac intensivist must have a comprehensive understanding of cardiopulmonary physiology and the sequelae of cardiopulmonary bypass. In this concise review, targeted at intensivists and surgeons, we discuss the routine management of the postoperative cardiac surgical patient.

DATA SOURCE AND SYNTHESIS

Narrative review of relevant English-language peer-reviewed medical literature.

CONCLUSIONS

Critical care of the cardiac surgical patient is a complex and dynamic endeavor. Adequate fluid resuscitation, appropriate inotropic support, attention to rewarming, and ventilator management are key components. Patient safety is enhanced by experienced personnel, a structured handover between the operating room and ICU teams, and appropriate transfusion strategies.

Practice guidelines for perioperative blood management: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management*

The American Society of Anesthesiologists Committee on Standards and Practice Parameters and the Task Force on Perioperative Blood Management presents an updated report of the Practice Guidelines for Perioperative Blood Management.

Supplemental Digital Content is available in the text.

Blood Type O is not associated with increased blood loss in extensive spine surgery

STUDY OBJECTIVE

To investigate whether Type O blood group status is associated with increased intraoperative blood loss and requirement of blood transfusion in extensive spine surgery.

DESIGN

Retrospective comparative study.

SETTING

University-affiliated, non-profit teaching hospital.

MEASUREMENTS

Data from 1,050 ASA physical status 1, 2, 3, 4, and 5 patients who underwent spine surgeries involving 4 or more vertebral levels were analyzed. Patients with Type O blood were matched to similar patients with other blood types using propensity scores, which were estimated via demographic and morphometric data, medical history variables, and extent of surgery. Intraoperative estimated blood loss (EBL) was compared among matched patients using a linear regression model; intraoperative transfusion requirement in volume of red blood cells, fresh frozen plasma, platelet, cryoprecipitate, cell salvaged blood, volume of intraoperative infusion of hetastarch, 5% albumin, crystalloids, and hospital length of hospital (LOS) were compared using Wilcoxon rank-sum tests.

MAIN RESULTS

Intraoperative EBL and requirement of blood product transfusion were similar in patients with Type O blood group and those with other blood groups.

CONCLUSION

There was no association between Type O blood and increased intraoperative blood loss or blood transfusion requirement during extensive spine surgery, with similar hospital LOS in Type O and non-O patients.

Modified ultrafiltration during cardiopulmonary bypass and postoperative course of pediatric cardiac surgery

Context:

The use of cardiopulmonary bypass (CPB) provokes the inflammatory responses associated with ischemic/reperfusion injury, hemodilution and other agents. Exposure of blood cells to the bypass circuit surface starts a systemic inflammatory reaction that may causes post-CPB organ dysfunction, particularly in lungs, heart and brain.

Evidence Acquisition:

We investigated in the MEDLINE, PUBMED, and EMBASE databases and Google scholar for every available article in peer reviewed journals between 1987 and 2013, for related subjects to CPB with conventional or modified ultrafiltration (MUF) in pediatrics cardiac surgery patients.

Results:

MUF following separation from extracorporeal circulation (ECC) provides well known advantages in children with improvements in the hemodynamic, pulmonary, coagulation and other organs functions. Decrease in blood transfusion, reduction of total body water, and blood loss after surgery, are additional benefits of MUF.

Conclusions:

Consequently, MUF has been associated with attenuation of morbidity after pediatric cardiac surgery. In this review, we tried to evaluate the current evidence about MUF on the organ performance and its effect on post-CPB morbidity in pediatric patients.

The coagulopathy of cardiopulmonary bypass

There have been numerous publications on the coagulopathy of cardiopulmonary bypass (CPB). This review provides an introduction to the history and main components of current CPB circuits and summarizes the current knowledge of pathogenesis, prevention, and treatment of the CPB coagulopathy. It encompasses an overview of intra- and postoperative monitoring of coagulation with special emphasis on the near-patient testing, its main complications, and the transfusion support, while taking into account the major changes in the technology used and supportive care provided since its inception.

Thrombelastography (TEG) or thromboelastometry (ROTEM) to monitor haemotherapy versus usual care in patients with massive transfusion

BACKGROUND

Severe bleeding and coagulopathy as a result of massive transfusion are serious clinical conditions that are associated with high mortality. Thromboelastography (TEG) and thromboelastometry (ROTEM) are increasingly used to guide transfusion strategy but their roles remain disputed.

OBJECTIVES

To systematically assess the benefits and harms of a TEG or ROTEM guided transfusion strategy in randomized trials involving patients with severe bleeding.

SEARCH STRATEGY

Randomized clinical trials (RCTs) were identified from electronic databases: Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 9); MEDLINE; EMBASE; Science Citation Index Expanded; International Web of Science; CINAHL; LILACS; and the Chinese Biomedical Literature Database (up to 31st October 2010). We contacted trial authors, authors of previous reviews, and manufacturers in the field.

SELECTION CRITERIA

We included all RCTs, irrespective of blinding or language, that compared transfusion guided by TEG or ROTEM to transfusion guided by clinical judgement and standard laboratory tests, or both.

DATA COLLECTION AND ANALYSIS

Two authors independently abstracted data; they resolved any disagreements by discussion. We presented pooled estimates of the intervention effects on dichotomous outcomes as relative risks (RR) and on continuous outcomes as mean differences, with 95% confidence intervals (CI). Our primary outcome measure was all cause mortality. We performed subgroup and sensitivity analyses to assess the effect of TEG or ROTEM in adults and children on various clinical and physiological outcomes. We assessed the risk of bias through assessment of trial methodological components and the risk of random error through trial sequential analysis.

MAIN RESULTS

We included nine RCTs with a total of 776 participants; only one trial had a low risk of bias. We found two ongoing trials but were unable to retrieve any data from them. Compared with standard treatment, TEG or ROTEM showed no statistically significant effect on overall mortality (3.78% versus 5.11%, RR 0.77, 95% CI 0.35 to 1.72; I(2) = 0%) but only five trials provided data on mortality. Our analyses demonstrated a statistically significant effect of TEG or ROTEM on the amount of bleeding (MD -85.05 ml, 95% CI -140.68 to -29.42; I(2) = 26%) but failed to show any statistically significant effect on other predefined outcomes.

AUTHORS' CONCLUSIONS

There is an absence of evidence that TEG or ROTEM improves morbidity or mortality in patients with severe bleeding. Application of a TEG or ROTEM guided transfusion strategy seems to reduce the amount of bleeding but whether this has implications for the clinical condition of patients is still uncertain. More research is needed.

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.

Point-of-care coagulation testing and transfusion algorithms

Patients with cardiovascular disease have an array of haemostasis disorders that predispose to the development of thrombotic and embolic disease states. These patients are often maintained on anti-thrombotic medication to prevent adverse cardiovascular events. Patients undergoing cardiac surgery also have haemostatic disorders that include their intrinsic disease state, adjunctive medication, and the coagulation disturbances induced by cardiopulmonary bypass. The following review introduces the monitors that are available for monitoring perioperative coagulation, with an emphasis on cardiovascular surgery. Heparin monitors, platelet function monitors for use in transfusion algorithms, and monitoring anti-platelet drugs will be discussed.

Coagulation and fibrinolytic protein kinetics in cardiopulmonary bypass

The development of Cardiopulmonary Bypass (CPB) catopulted the field of cardiothoracic surgery into a new dimension--one that changed the lives of individuals with congenital and acquired heart disease worldwide. Despite its contributions, CPB has clear limitations and creates unique challenges for clinicians and patients alike, stemming from profound hemostatic pertubations and accompanying risk for bleeding and possibly thrombotic complications.

ABO blood group and bleeding after coronary artery bypass graft surgery

Low circulating von Willebrand factor levels increase the risk of bleeding after cardiac surgery. Patients with blood group O may be at greatest risk owing to lower baseline levels of von Willebrand factor compared with patients with other blood groups, and perioperative hemodilution during cardiac surgery may reduce von Willebrand factor to critical levels in these patients. This study tested the hypothesis that patients with blood group O are at increased risk for postoperative bleeding following cardiac surgery, and determined whether the blood group affected perioperative assessment of primary hemostasis. Using multivariate linear regression models that included preoperative and intraoperative covariates, the risk factors for postoperative bleeding were evaluated in 877 patients undergoing primary, nonemergent coronary artery bypass surgery at a university hospital. In a subset of these patients, we measured perioperative in-vitro bleeding times (PFA-100 analyzer) to determine whether there were measurable differences in primary hemostasis between patients with blood type O and those with other blood groups. Patients with blood group O did not have increased bleeding after cardiac surgery compared with patients with other blood types. In addition, while blood group O patients had laboratory evidence for abnormal primary hemostasis before surgery, there were no measurable differences in postoperative primary hemostasis in patients with different blood types. In conclusion, although we identified clinical and procedural factors that were independently associated with bleeding, blood group was not one of these factors.

Thrombelastography: current clinical applications and its potential role in interventional cardiology

Thrombelastography is a bedside blood test used to assess patients' haemostatic status. It has a well-established role in hepatobiliary and cardiac surgery and is also used in obstetrics and trauma medicine to assess coagulation and identify the causes of post-operative bleeding. It is not routinely used in the diagnosis or treatment of thrombosis although recently it has been shown to predict thrombotic events post-operatively and after percutaneous intervention (PCI). In cardiovascular medicine the importance of the platelet in the pathophysiology of vascular events is increasingly apparent. As a result antiplatelet therapy is a cornerstone of the treatment for coronary disease, particularly in the setting of acute coronary syndromes. The increasing utilization of stents, particularly drug-eluting devices, in PCI has also necessitated widespread use of antiplatelet agents to minimize the risk of stent thrombosis. A quick, accurate and reliable test to measure the effect of platelet inhibition by antiplatelet agents on clotting in an individual patient would be of profound clinical value. The results from such a test could provide prognostic information, allow treatment with antiplatelet agents to be tailored to the individual and identify resistance to one or more of these agents. Optimization and tailoring of anti-platelet therapy in patients with cardiovascular disease, particularly those undergoing PCI, using such a test may reduce morbidity and mortality from thrombotic and haemorrhagic complications. Current methods of assessing platelet activity measure platelet count and function in isolation. Optical aggregation is the most widely used method for assessing platelet function but it is relatively time consuming, measures platelet function in isolation rather than in the context of clot formation and is not a bedside test. By contrast the modified thrombelastograph platelet mapping kit marketed by Haemoscope can be used to assess the effects of antiplatelet agents on ex vivo blood clotting, thus giving a measurement more relevant to in vivo responses. This represents a potentially powerful tool to assess response of individual patients to antiplatelet therapy, particularly in the context of PCI.

Management of antiplatelet therapy for minimization of bleeding risk before cardiac surgery

Antiplatelet therapy is commonly administered for primary and secondary prevention of stroke, recurrent angina, myocardial infarction, and death in patients with cardiovascular disorders. It also is associated with an increased risk of bleeding. We describe the management of antiplatelet therapy in patients undergoing coronary artery bypass graft surgery. In addition, we provide basic information about the mechanisms of action by which the most common antiplatelet agents inhibit platelet function. This information is integrated with results from pharmacologic studies and clinical trials. Determining the net effect in patients undergoing coronary artery bypass graft surgery requires knowledge about the pharmacokinetics, pharmacodynamics, and clinical efficacy of each drug, and an estimation of the absolute thrombotic versus hemorrhagic risk for each patient.

Impact of modified ultrafiltration on morbidity after pediatric cardiac surgery

Cardiopulmonary bypass is a double-edged sword. Without it, corrective cardiac surgery would not be possible in the majority of children with congenital heart disease. However, much of the perioperative morbidity that occurs after cardiac surgery can be attributed to a large extent to pathophysiologic processes engendered by extracorporeal circulation. One of the challenges that has confronted pediatric cardiac surgeons has been to minimize the consequences of cardiopulmonary bypass. Ultrafiltration is a strategy that has been used for many years in an effort to attenuate the effects of hemodilution that occur when small children undergo surgery with cardiopulmonary bypass. Over the past several years, a modified technique of ultrafiltration, commonly known as modified ultrafiltration, has been used with increasing enthusiasm. Multiple studies have been undertaken to assess the effects of modified ultrafiltration on organ function and postoperative morbidity following repair of congenital heart defects. This review attempts to evaluate current available scientific evidence on the impact of modified ultrafiltration on organ function and morbidity after pediatric cardiac surgery.

Use of cardiopulmonary bypass for lung transplantation: a 10-year experience

OBJECTIVE

The use of cardiopulmonary bypass (CPB) for lung transplantation (LTx) has been reported previously. This study reports the authors' experience of planned and unplanned use of cardiopulmonary bypass for LTx.

DESIGN

Case series.

SETTING

A university teaching hospital.

PARTICIPANTS

Patients undergoing LTx.

INTERVENTIONS

A retrospective analysis of the charts of all patients having undergone LTx over the last 10 years.

MEASUREMENTS AND MAIN RESULTS

Among 140 LTx, 23 (16%) were performed with the use of CPB. CPB was planned in 11 cases and unplanned in the 12 other cases. The use of CPB is associated with a longer period of postoperative mechanical ventilation, more pulmonary edema, more blood transfusion requirement, and an increase in postoperative mortality at 48 hours and 1 month. Surgical difficulties related to the dissection of the native left lung and acute right ventricular failure are the main reasons for unscheduled use of CPB.

CONCLUSION

Scheduled and unscheduled CPB for LTx are associated with an increased mortality at 1 month and 1 year.

Correlation of perioperative platelet function and coagulation tests with bleeding after cardiopulmonary bypass surgery

The authors evaluated the correlation of post-cardiopulmonary bypass surgery bleeding, measured as 24-hour chest tube output/kilogram body weight, with platelet function tests using glass bead adhesion and Thrombelastograph Platelet Mapping (Haemoscope Corporation, Niles, Ill); coagulation tests; patient characteristics; surgery parameters; and visual assessment of surgical field bleeding before closure as not bleeding (code 1), oozing (code 2), and excessive bleeding (code 3). All platelet function and coagulation tests indicated significant dysfunction 15 minutes after protamine neutralization of heparin. With the exception of glass bead adherence, these assays indicated poor recovery of function 1 hour postoperatively. By multiple regression, the most significant predictors of postoperative bleeding were a low body mass index (BMI) (P < 0.0001), lowest core body temperature (P = 0.0006), and cross clamp time (P < 0.0001). Low core temperature was significantly (P < 0.0001) correlated with cross clamp time, which the authors believe is the most likely cause of coagulation and platelet dysfunction. None of the platelet function tests significantly correlated with bleeding. Looking at the highest quartile of chest tube output patients (n = 19) versus the upper and lower 50th percentile of coagulation and platelet function, bleeding could be explained for 11 patients by BMI plus surgery parameters along with coagulation and/or platelet dysfunction. In three cases without negative surgery parameters, coagulation dysfunction was observed. The remaining five cases did not give a clear indication of which parameters were primarily responsible for the bleeding.

The kaolin-activated Thrombelastograph predicts bleeding after cardiac surgery

OBJECTIVE

The objective of this study was to determine the relationship of the kaolin-activated Thrombelastograph (TEG) with postoperative bleeding and laboratory tests of coagulation in the setting of cardiac surgery with the routine use of -aminocaproic acid.

DESIGN

Prospective observational study.

SETTING

An adult heart center at a tertiary referral, university hospital.

PARTICIPANTS

Thirty adult cardiac surgical patients.

INTERVENTIONS

The kaolin-activated TEG, platelet counts, prothrombin times, activated partial thromboplastin times, and fibrinogen levels were measured before induction of anesthesia, during cardiopulmonary bypass, and on arrival in the intensive care unit. Mediastinal and thoracostomy drainage were measured every hour for 4 hours after arrival in the intensive care unit.

MEASUREMENTS AND MAIN RESULTS

Correlation and multivariate linear regression modeling were used to describe relationships among coagulation tests, TEG parameters, and early postoperative bleeding. The TEG maximum amplitude (MA) parameter correlated well with postoperative bleeding (r = -0.6, p = 0.0018), more so than platelet count (r = -0.45, p = 0.02), fibrinogen level (r = -0.40, p = 0.06), or prothrombin time (r = 0.43, p = 0.02). The receiver operating characteristic curve c-index describing MA as a predictor for postoperative bleeding is 0.78. Abnormalities in all the laboratory test results were associated with an abnormal MA.

CONCLUSIONS

In conclusion, the kaolin-activated TEG is associated with early coagulopathic bleeding. It may reflect the severity of a global coagulopathy affecting both platelets and coagulation factors and be a guide to incremental prohemostatic therapy in this setting.

Perioperative Evaluation of Bleeding Diathesis

The differential diagnosis of a long APTT with a normal prothrombin time can be due to either a clotting factor deficiency or the presence of an inhibitor, which can be distinguished by using a plasma-mixing study. The various clotting factor deficiency states are reviewed. Clinical bleeding following cardiac bypass surgery due to acquired factor V and thrombin antibodies is also reviewed.

Effects of Hemodilution, Blood Loss, and Consumption on Hemostatic Factor Levels During Cardiopulmonary Bypass

OBJECTIVES

The purpose of this study was to determine quantitatively the effects of consumption, hemodilution, and blood loss on coagulation and fibrinolytic factor levels during cardiopulmonary bypass.

DESIGN

A combination of measured levels of prothrombin, antithrombin, fibrinogen, plasminogen, and antiplasmin along with their activation markers F1.2, thrombin-antithrombin complex, fibrinopeptide A, plasmin-antiplasmin complex, and D-dimer were used with a computer model of each patient's vascular and hemostatic systems to estimate the cardiopulmonary bypass-associated loss of each factor because of hemodilution, blood loss, and consumption.

SETTING

University hospital.

PARTICIPANTS

Nine patients undergoing coronary artery bypass graft surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

At baseline, it was estimated that on average 2%, 3%, and 25%, respectively, of the baseline liver secretion of plasminogen, prothrombin,and fibrinogen were consumed by activation of these proteins. During cardiopulmonary bypass, thrombin and plasmin generation were increased, whereas fibrin generation was decreased because of heparin. Compared with baseline, hemodilution during cardiopulmonary bypass resulted in an average 35% +/- 7% decrease in the concentration of coagulation and fibrinolytic proteins, whereas blood loss was responsible for an average 6% +/- 5% decrease in these proteins. Blood loss varied substantially among patients, resulting in <1% to 14% decreases in hemostatic protein levels. On average, consumption because of activation resulted in less than a 1% drop in the concentration of coagulation and fibrinolytic factors during cardiopulmonary bypass.

CONCLUSIONS

Hemodilution is the primary cause of the drop in coagulation and fibrinolytic proteins during routine cardiopulmonary bypass, followed by blood loss, whereas consumption accounts for less than a 1% drop in most patients.