ABO blood group and bleeding after coronary artery bypass graft surgery. Blood Coagul Fibrinolysis. 2007;18:781-785. [PMID: 17982320 DOI: 10.1097/MBC.0b013e3282f1029c]

Blood Type as a Potential Predictor of Hemorrhagic Risk in Patients Undergoing Partial Hepatectomy for Colorectal Liver Metastasis

Background: Hepatic resection is performed for liver lesions and requires careful preoperative planning to minimize bleeding. Blood type O, associated with lower von Willebrand factor (vWF) levels, may increase bleeding risk. This study investigates the relationship between the ABO blood type and perioperative bleeding in partial hepatectomy for colorectal liver metastases (CRLMs). Methods: Out of 563 patients who underwent hepatectomy, 135 cases were analyzed for CRLM at Carmel Medical Center (2013-2023). Patients were categorized into blood type O (61 patients) and non-O (74 patients) groups. Data on perioperative hemoglobin levels, blood loss, coagulation parameters, transfusion needs, and complications were assessed using χ2, t-tests, and ANOVA (p < 0.05). Results: No significant differences were observed for estimated blood loss (474.3 ± 696 mL for O vs. 527.8 ± 599 mL for non-O; p = 0.29), intraoperative hemoglobin drop (p = 0.613), or transfusion rates (24.59% for O vs. 28.37% for non-O; p = 0.698). Although non-O patients had a higher postoperative INR (p = 0.035), this did not correlate with increased bleeding or transfusion needs. Conclusions: Blood type O does not significantly affect perioperative bleeding or transfusion requirements in partial hepatectomy for CRLM. Further research is needed to better understand the significance of the ABO blood type.

Blood group AB is associated with reduced blood loss but also elevated cardiovascular mortality in aortocoronary bypass surgery

Patient blood group (BG) is predictive for von-Willebrand-factor (VWF) and Factor VIII variation. The clinical impact of this ABO-effect on blood loss, cardiovascular complications and outcome has been described for several patient cohorts. The aim of this study was to investigate the impact of patient BG on blood loss and outcome after coronary artery bypass surgery (CABG). Patient records, intraoperative data and perioperative transfusion records of 5713 patients receiving an on-pump CABG procedure between 05/2004 and 12/2018 were analyzed. A logistic regression model for death due to perioperative myocardial ischaemia (PMI) was developed from initially 24 variables by using an univariate and multivariate selection process. BG AB patients required less blood transfusions as compared to the other blood groups, especially in case of emergency operations. However, BG AB patients also had a higher mortality which was due to secondary cardiovascular complications. The impact of blood type on the rate of cardiovascular mortality was confirmed in the logistic regression model. BG AB patients have a worse outcome after CABG surgery due to an increased incidence of fatal cardiovascular complications. As perioperative myocardial ischemia due to graft occlusion appears to be the most likely explanation, stricter anticoagulation for BG AB patients should be discussed.

Evaluation of blood type as a potential risk factor for hemorrhage during vaginal hysterectomy

OBJECTIVE

To examine the association between the O blood type and bleeding tendency in patient undergoing vaginal hysterectomy.

METHODS

This was a retrospective cohort study including all women who had undergone vaginal hysterectomy at our institution between January 2015 and September 2020. All women underwent blood type and complete blood count testing pre- and post-operatively. The estimated intraoperative blood loss, the need for blood transfusion, pre- and postoperative hemoglobin and hematocrit measurements and surgical data were recorded for all patients. Patients with known coagulopathies or those taking antithrombotic medications were excluded from the study. Statistical analysis was performed using student t, χ2, Fischer exact, and ANOVA tests as well as a stepwise logistic regression model.

RESULTS

The study included 106 patients (35.2 %) with O and 195 patients (64.8 %) with non-O (i.e., A, B or AB) blood types. The O blood type was significantly associated with a higher risk for moderate blood loss (defined as a pre- to postoperative Hb or HCT drop >2gr or >6 %, respectively) (p = 0.012), but not with severe (defined as a Hb or HCT drop of >3gr or >9 %, respectively) perioperative bleeding, nor with the need for blood transfusion.

CONCLUSION

The O blood type was found to be significantly associated with moderate but not with severe intraoperative bleeding during and following vaginal hysterectomy.

ABO Blood Group and Bleeding and Survival in VA-ECMO Patients

ABO blood group has been shown to be a major determinant of plasma von Willebrand factor (vWF) levels. O blood group is associated with the lowest vWF levels and confers an increased risk of hemorrhagic events, while AB blood group has the highest levels and is associated with thromboembolic events. We hypothesized in extracorporeal membrane oxygenation (ECMO) patients that O blood type would have the highest and AB blood type would have the lowest transfusions, with an inverse relationship to survival. A retrospective analysis of 307 VA-ECMO patients at a major quaternary referral hospital was performed. The distribution of blood groups included 124 group O (40%), 122 group A (40%), 44 group B (14%), and 17 group AB (6%) patients. Regarding usage of packed red blood cells, fresh frozen plasma, and platelets, there was a non-statistically significant difference in transfusions, with group O having the least and group AB having the most requirements. However, there was a statistically significant difference in cryoprecipitate usage when comparing to group O: group A (1.77, 95% CI: 1.05-2.97, P < .05), group B (2.05, 95% CI: 1.16-3.63, P < .05), and group AB (3.43, 95% CI: 1.71-6.90, P < .001). Furthermore, a 20% increase in length of days on ECMO was associated with a 2-12% increase in blood product usage. The cumulative 30-day mortality rate for groups O and A was 60%, group B was 50%, and group AB was 40%; the 1-year mortality rate for groups O and A was 65%, group B was 57%, and group AB was 41%; however, the mortality differences were not statistically significant.

BLOOD TYPE O IS A RISK FACTOR FOR HYPERFIBRINOLYSIS AND MASSIVE TRANSFUSION AFTER SEVERE INJURY

ABSTRACT

Background: Blood type O is the most common blood type and has lower von Willebrand factor (vWF) levels (25%-35% lower than non-O blood types). von Willebrand factor is important for initiating platelet attachment and binding factor VIII. We hypothesized that patients with type O blood are at an increased risk of trauma-induced coagulopathy and bleeding post injury. Study Design: Adult trauma activations with known blood type at a level I trauma center with field systolic blood pressure < 90 mm Hg were studied retrospectively. The relationships of blood group O versus non-O to coagulation assays, massive transfusion (MT), ventilator-free days, and mortality were adjusted for confounders. Hyperfibrinolysis (HF) was defined as thromboelastogram of percent lysis in 30 min > 3%, and fibrinolysis shutdown was defined as percent lysis in 30 min < 0.9%. von Willebrand factor activity was quantified on 212 injured patients using a STAGO apparatus. Results: Overall, 268 patients met criteria. Type O patients were more likely to develop HF than non-type O blood patients (43% vs. 29%, P = 0.06) and had significantly lower vWF activity (222% vs. 249%, P = 0.01). After adjustment for New Injury Severity Score and blunt mechanism, type O had higher odds of HF (odds ratio, 1.94, 95% confidence interval, 1.09-3.47) and increased odds of MT (odds ratio, 3.02; 95% confidence interval, 1.22-7.49). Other outcomes were not significantly affected. Conclusion: Type O patients with hypotension had increased HF and MT post injury, and these were associated with lower vWF activity. These findings have implications for the monitoring of HF in patients receiving type O whole-blood transfusions post injury.

Effect of Different Blood Groups on Long-Term Outcomes of Surgical Revascularisation

BACKGROUND

ABO blood groups are considered to be associated with cardiovascular disease. Nonetheless, the definite effect of ABO blood groups on the clinical outcome of coronary artery bypass graft surgery (CABG) is still undetermined. We evaluated whether ABO blood groups can predict long-term major adverse cardiocerebrovascular events (MACCE) in CABG patients.

METHOD

In this retrospective cohort study, we retrieved the clinical files of eligible patients treated with isolated CABG in our hospital between March 2007 and March 2016. We divided the patients into four ABO subgroups. The primary study endpoints were the occurrence of all-cause mortality and MACCE during long-term follow-ups. We used Cox regression survival analysis to define the association of ABO blood groups with the occurrence of MACCE.

RESULTS

Of 17,892 patients who underwent isolated CABG, 17,713 (mean age, 61.19±9.47 years, 74.6% male) were successfully followed, and their data used in the final analysis. Our multivariable analysis demonstrated that patients with different blood groups had similar 5-year mortality and 5-year MACCE.

CONCLUSIONS

Our findings suggest that in patients who underwent CABG, ABO blood groups were not associated with long-term MACCE.

Impact of ABO blood group on bleeding complications after surgery for acute type A aortic dissection

Excessive bleeding is a serious complication associated with impaired survival after surgery for acute type A aortic dissection (ATAAD). Different ABO blood groups are associated with variable levels of circulating von Willebrand factor and therefore potentially altered risks of surgical haemorrhage. The current study aimed to assess the impact of blood group on bleeding complications after ATAAD surgery. This was a retrospective cohort study including 336 patients surgically treated for ATAAD between January 2004 and January 2019. Patients with blood group O were compared with non-O patients. In total, 152 blood group O patients were compared with 184 non-O patients. There were no differences in rates of massive bleeding (27.0 vs. 25.5%, P = 0.767) or re-exploration for bleeding (16.4 vs. 13.0%, P = 0.379) in blood group O and non-O patients, respectively. Median chest tube output 12 h after surgery was 520 ml (350-815 ml) in blood group O and 490 ml (278-703 ml) in non-O patients (P = 0.229). Blood group O patients received more fibrinogen concentrate (6.1 ± 4.0 vs. 4.9 ± 3.3 g, P = 0.023) but administered units of packed red blood cells [5 (2-8) vs. 4 (2-9) U, P = 0.736], platelets [4 (2-4) vs. 3 (2-5) U, P = 0.521] or plasma [4 (1-7) vs. 4 (0-7) U, P = 0.562] were similar. This study could not demonstrate any association between blood group and bleeding after surgery for ATAAD. It cannot be ruled out that potential differences were levelled out by blood group O patients receiving significantly more fibrinogen concentrate.

Blood type association with bleeding outcomes at delivery in a large multi-center study

Postpartum hemorrhage is a leading cause of maternal death globally. Recent studies have associated Type-O group to increased risk of bleeding. We aimed to determine if women with Type-O blood are at higher risk of PPH. This is a retrospective cohort analysis of a multi-center database included women admitted to labor and delivery from January 2015 to June 2018. All deliveries resulting in live birth were included. Association between Type-O and non Type-O were examined using chi-square test and fishers exact test. Prevalence of postpartum hemorrhage, estimated blood loss, drop in hematocrit and red blood cell transfusion were compared. The matched sample included 40,964 Type-O and the same number of no Type-O. The overall prevalence of postpartum hemorrhage was 6.4%, and there was no difference in the prevalence of PPH among Type-O compared to non Type-O (6.38% vs. 6.37% respectively; p = 0.96). There was no difference in hematocrit drop and estimated blood loss between Type-O and non Type-O in all deliveries. However, in cesarean delivery there was a significant difference in blood loss among the two groups. Finally, Type-O had 1.09-fold increased risk for transfusion compared to non Type O (95% CI 0.9-1.34). There is an association between Type-O group and risk of bleeding in women undergoing cesarean delivery. More prospective studies, taking into account coagulation profile, platelet count and tissue factors, are needed to draw a conclusion on whether ABO system can be considered a heritable risk of postpartum hemorrhage.

ABO blood group is related to bleeding in cardiac surgery

BACKGROUND

Increased bleeding and blood product transfusions during cardiac surgery are associated with poor outcomes. The patient's ABO blood group is related to hemostatic balance, although it is unclear whether this influences bleeding during cardiac surgery. This study aimed to evaluate whether ABO blood group is related to bleeding during cardiac surgery.

METHODS

This retrospective study evaluated data from 17,058 cardiac surgical procedures that were performed in four Danish cardiosurgical centers. Data regarding chest tube drainage and transfusion volumes were retrieved from a clinical database and combined with information regarding ABO group. The primary outcome was chest tube drainage volume and the secondary outcomes were transfused volumes of various blood products.

RESULTS

Blood group O had the largest chest tube drainage volume (mean: 745 mL, 95% CI: 720-771 mL) and blood group AB had the smallest volume (mean: 664 mL, 95% CI: 598-731 mL). The inter-group difference in the mean drainage volume was 81 mL (95% CI: 8-154 mL, P < .05). Patients with blood group A or blood group B had mean drainage volumes that were between the volumes for groups AB and O. Relative to group O, group AB received smaller mean volumes of all blood products. The most pronounced difference was in platelet concentrates, with mean values of 170 mL for group O (95% CI: 157-184 mL) and 63 mL for group AB (95% CI: 34-92 mL).

CONCLUSION

The patient's ABO group appears to be related to volumes of chest tube drainage and transfused blood products during cardiac surgery.

Association of ABO blood group with postoperative total bleeding volume in patients undergoing total hip arthroplasty

BACKGROUND AND OBJECTIVES

As individuals with blood types A, B and AB have approximately 25% higher levels of vWF than those with type O, the risk of developing venous thrombotic events has been investigated in a number of clinical studies, but whether individuals with type O blood experience increased bleeding remains to be clarified. The purpose of this study was to evaluate an association of ABO blood group with intraoperative bleeding and postoperative total bleeding in patients undergoing total hip arthroplasty.

MATERIALS AND METHODS

We prospectively recruited 84 women who were undergoing total hip arthroplasty. The differences between blood groups in mean age, body weight, preoperative and postoperative Hct levels, and postoperative/preoperative Hct ratio, intraoperative bleeding volume (IBV), and total bleeding volume (TBV) were evaluated.

RESULTS

Twenty-six patients had type A blood, 17 had type B, 9 had type AB, and 30 had type O. There were no significant differences in mean age, body weight or operating time between the different ABO blood groups. While there was no significant difference in these Hct levels or IBV among the different blood groups, there was a significant difference in TBV between type O and type AB, and between type O and non-type O.

CONCLUSION

Our study in patients undergoing total hip arthroplasty suggests that patients in blood group O tend to have large amounts of bleeding.

Blood transfusion in major emergency abdominal surgery

BACKGROUND

Major emergency abdominal surgery is associated with excess mortality. Transfusion is known to be associated with increased morbidity and emergency surgery is an independent risk factor for perioperative transfusion. The primary objectives of this study were to identify risk factors for transfusion, and secondarily to investigate the influence of transfusion on clinical outcomes after major emergency abdominal surgery.

STUDY DESIGN AND METHODS

This study combined retrospective observational data including intraoperative, postoperative, and transfusion data in patients undergoing major emergency abdominal surgery from January 2010 to October 2016 at a Danish university hospital. The primary outcome was a transfusion of any kind from initiation of surgery to postoperative day 7. Secondary outcomes included 7-, 30-, 90-day and long-term mortality (median follow-up = 34.6 months, IQR = 13.0-58.3), lengths of stay, and surgical complication rate (Clavien-Dindo score ≥ 3a).

RESULTS

A total of 1288 patients were included and 391 (30%) received a transfusion of any kind. Multivariate logistic regression identified age, hepatic comorbidity, cardiac comorbidity, post-surgical anemia, ADP-receptor inhibitors, acetylsalicylic acid, anticoagulants, and operation type as risk factors for postoperative transfusion. 60.1% of the transfused patients experienced a serious surgical complication within 30 days of surgery compared with 28.1% of the non-transfused patients (p < 0.001). Among patients receiving a postoperative transfusion, unadjusted long-term mortality was increased with a hazard ratio of 3.8 (95% CI 2.9-5.0), p < 0.01. Transfused patients had significantly higher mortality at 7-, 30-, 90- and long-term, as well as a longer hospital stay but in the multivariate analyses, transfusion was not associated with mortality.

CONCLUSION

Peri- and postoperative transfusion in relation to major emergency abdominal surgery was associated with an increased risk of postoperative complications. The potential benefits and harms of blood transfusion and clinical significance of pre- and postoperative anemia after major emergency abdominal surgery should be further studied in clinical prospective studies.

Blood group O is a risk factor for delayed post-polypectomy bleeding

BACKGROUND

Blood group O of ABO blood group system is considered as a risk factor for various bleeding events, but the relationship with endoscopic treatment-associated bleeding has yet to be investigated. This study aimed to evaluate whether blood group O is associated with delayed bleeding after colorectal endoscopic resection.

METHODS

This was a retrospective observational study based on medical records at four university hospitals in Japan. We reviewed the records for consecutive patients who underwent colorectal endoscopic resection from January 2014 through December 2017. The primary outcome was the incidence of delayed bleeding, defined as hematochezia or melena, requiring endoscopy, transfusion, or any hemostatic intervention up to 28 days after endoscopic resection. Multivariate logistic regression analysis was performed to adjust the impact of blood group O on the delayed bleeding.

RESULTS

Among 10,253 consecutive patients who underwent colorectal endoscopic resection during the study period, 8625 patients met the criteria. In total, delayed bleeding occurred in 255 patients (2.96%). The O group had significantly more bleeding events compared with the non-O group (A, B, and AB) (relative risk, 1.62 [95% confidence interval, 1.24-2.10]; P < 0.001). In multivariate logistic regression analysis, blood group O remained an independent risk factor for the bleeding (adjusted odds ratio, 1.60 [95% confidence interval, 1.18-2.17]; P = 0.002).

CONCLUSIONS

Blood group O was associated with an increased risk of delayed bleeding in patients undergoing colorectal endoscopic resection. Preoperative screening for ABO blood group could improve risk assessments.

ABO blood group does not impact incidence or outcomes of surgery for acute type A aortic dissection

Objectives. To evaluate the distribution and impact of ABO blood groups on postoperative outcomes in patients undergoing surgery for acute type A aortic dissection (ATAAD). Design. A total of 1144 surgical ATAAD patients from eight Nordic centres constituting the Nordic consortium for acute type A aortic dissection (NORCAAD) were analysed. Blood group O patients were compared to non-O subjects. The relative frequency of blood groups was assessed with t-distribution, modified for weighted proportions. Multivariable logistic regression was performed to identify independent predictors of 30-day mortality. Cox regression analyses were performed for assessing independent predictors of late mortality. Results. There was no significant difference in the proportions of blood group O between the study populations in the NORCAAD registry and the background population (40.6 (95% CI 37.7-43.4)% vs 39.0 (95% CI 39.0-39.0)%). ABO blood group was not associated with any significant change in risk of 30-day or late mortality, with the exception of blood group A being an independent predictor of late mortality. Prevalence of postoperative complications was similar between the ABO blood groups. Conclusions. In this large cohort of Nordic ATAAD patients, there were no associations between ABO blood group and surgical incidence or outcomes, including postoperative complications and survival.

ABO Blood Group and Transfusions In the Intraoperative and Postoperative Period After LVAD Implantation

OBJECTIVES

To assess whether blood group O patients undergoing left ventricular assist device (LVAD) insertion have higher perioperative transfusion requirements, postoperative chest tube output, and postoperative changes in hematocrit.

DESIGN

Retrospective review of 116 LVAD patients from August 2015 to May 2018.

SETTING

Single-institution, urban academic medical center.

PARTICIPANTS

One hundred sixteen LVAD patients analyzed by blood group: group O (n = 49) versus non-O (n = 67).

INTERVENTIONS

Transfusions in the combined intraoperative and postoperative period at 7 days and 90 days after LVAD implantation, chest tube output in the first 24 hours, and hematocrit change in the first 48 hours postoperatively.

RESULTS

There was no difference between group O and non-O within the univariable analysis for both 7-day and 90-day transfusion rates. Adjusting for covariables, blood type O was not associated with packed red blood cells transfusion after accounting for multiple comparisons (odds ratio 1.33 [1.07-1.66], p = 0.01, where p < 0.005 was considered statistically significant as a Bonferroni correction was performed to control the familywise error rate). Additionally, there was no difference in chest tube output over the first 24 hours (1,129 v 1,057 mL, p = 0.47) or hematocrit change in the first 48 hours postoperatively (3.49 v 4.53%, p = 0.15).

CONCLUSION

O blood group is not a significant predictor of transfusion requirements in the combined intraoperative and postoperative period up to 90 days after LVAD implantation.

Antithrombotic therapy in ventricular assist device (VAD) management: From ancient beliefs to updated evidence. A narrative review

Platelets play a key role in the pathogenesis of ventricular assist device (VAD) thrombosis; therefore, antiplatelet drugs are essential, both in the acute phase and in the long-term follow-up in VAD management. Aspirin is the most used agent and still remains the first-choice drug for lifelong administration after VAD implantation. Anticoagulant drugs are usually recommended, but with a wide range of efficacy targets. Dual antiplatelet therapy, targeting more than one pathway of platelet activation, has been used for patients developing a thrombotic event, despite an increased risk of bleeding complications. Although different strategies have been attempted, bleeding and thrombotic events remain frequent and there are no uniform strategies adopted for pharmacological management in the short and mid- or long-term follow up. The aim of this article is to provide an overview of the evidence from randomized clinical trials and observational studies with a focus on the pathophysiologic mechanisms underlying bleeding and thrombosis in VAD patients and the best antithrombotic regimens available.

Is ABO blood group truly a risk factor for thrombosis and adverse outcomes?

ABO blood type is one of the most readily available laboratory tests, and serves as a vital determinant in blood transfusion and organ transplantation. The ABO antigens are expressed not only on red blood cell membranes, determining the compatibility of transfusion, but also on the surface of other human cells, including epithelium, platelet and vascular endothelium, therefore extending the research into other involvements of cardiovascular disease and postoperative outcomes. ABO blood group has been recognized as a risk factor of venous thrombosis embolism since the 1960’s, effects now understood to be related to ABO dependent variations are procoagulant factor VIII (FVIII) and von Willebrand factor (vWF) levels. Levels of vWF, mostly genetically determined, are strongly associated with venous thromboembolism (VTE). It mediates platelet adhesion aggregation and stabilizes FVIII in plasma. Moreover, many studies have tried to identify the relationship between ABO blood types and ischemic heart disease. Unlike the clear and convincing associations between VTE and ABO blood type, the link between ABO blood type and ischemic heart disease is less consistent and may be confusing. Other than genetic factors, ischemic heart disease is strongly related to diet, race, lipid metabolism and economic status. In this review, we’ll summarize the data relating race and genetics, including ABO blood type, to VTE, ischemic heart disease and postoperative bleeding after cardiac surgery.

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.

ABO blood group, hypercoagulability, and cardiovascular and cancer risk

The antigens of the ABO system (A, B, and H determinants, respectively) consist of complex carbohydrate molecules. It has been known for nearly half a century that the ABO blood group exerts a major influence on plasma levels of the von Willebrand factor (VWF)-factor VIII (FVIII) complex and that normal group O individuals have significantly lower levels of VWF and FVIII than do non-O individuals. As a consequence, several investigators have studied the association between ABO blood group and the risk of developing bleeding or thrombotic events. A number of epidemiological studies have also analyzed the biologic relevance of this interaction by assessing whether the ABO blood group could influence human longevity through the regulation of VWF-FVIII plasma levels. In this review, the molecular mechanisms by which the ABO blood group determines plasma VWF and consequently, FVIII levels, the possible clinical implications, and the current knowledge on the association between the ABO blood group and the risk of developing certain cancers will be reviewed.

Alterations of platelet function and clot formation kinetics after in vitro exposure to anti-A and -B

BACKGROUND

ABO-mismatched platelets (PLTs) are commonly transfused despite reported complications. We hypothesized that because PLTs possess A and B antigens on their surface, ABO-mismatched transfused or recipient PLTs could become activated and/or dysfunctional after exposure to anti-A or -B in the transfused or recipient plasma. We present here in vitro modeling data on the functional effects of exposure of PLTs to ABO antibodies.

STUDY DESIGN AND METHODS

PLT functions of normal PLTs of all ABO types were assessed before and after incubation with normal saline, ABO-identical plasma samples, or O plasma samples with varying titers of anti-A and anti-B (anti-A/B). Assays used for this assessment include PLT aggregation, clot kinetics, thrombin generation, PLT cytoskeletal function, and mediator release.

RESULTS

Exposure of antigen-bearing PLTs to O plasma with moderate to high titers of anti-A/B significantly inhibits aggregation, prolongs PFA-100 epinephrine closure time, disrupts clot formation kinetics, accelerates thrombin generation, reduces total thrombin production, alters PLT cytoskeletal function, and influences proinflammatory and prothrombotic mediator release.

CONCLUSIONS

Our findings demonstrate a wide range of effects that anti-A/B have on PLT function, clot formation, thrombin generation, PLT cytoskeletal function, and mediator release. These data provide potential explanations for clinical observations of increased red blood cell utilization in trauma and surgical patients receiving ABO-nonidentical blood products. Impaired hemostasis caused by anti-A/B interacting with A and B antigens on PLTs, soluble proteins, and perhaps even endothelial cells is a potential contributing factor to hemorrhage in patients receiving larger volumes of ABO-nonidentical transfusions.

An association of ABO non-identical platelet and cryoprecipitate transfusions with altered red cell transfusion needs in surgical patients

BACKGROUND

Transfusion of ABO non-identical plasma, platelets and cryoprecipitate is routine practice even though adverse effects can occur.

METHODS AND MATERIALS

Our hospital changed transfusion practice in 2005 and adopted a policy of providing ABO-identical blood components to all patients when feasible. We retrospectively compared the transfusion requirements, length of stay and in-hospital mortality in relation to ABO blood group in surgical patients who received platelet transfusions before and after this change to determine whether it resulted in any benefit.

RESULTS

Prior to the change in practice, both group B and AB patients received more ABO non-identical platelet transfusion (P=0·0004), required significantly greater numbers of red cell transfusions (P=0·04) and had 50% longer hospital stays (P=0·039) than group O and A patients. Following the policy change, there was a trend for fewer red cell transfusions (P=0·17) and length of stay in group B and AB patients than group O or A patients. Overall, the mortality rate per red cell transfusion decreased from 15·2 per 1000 to 11·0 per 1000 (P=0·013).

CONCLUSIONS

These results, in the context of previous findings, suggest that providing ABO-identical platelets and cryoprecipitate might be associated with reduction in transfusion requirements and improve outcomes in surgical patients.

Impact of genetic variation on perioperative bleeding

Variation in bleeding in the perioperative period is a complex and multifactorial event associated with immediate and delayed consequences for the patient and health care resources. Little is known about the complex genetic influences on perioperative bleeding. With the discovery of multiple variations in the human genome and ever-growing databases of well-phenotyped surgical patients, better identification of patients at risk of bleeding is becoming a reality. In this review, polymorphisms in the platelet receptor genes, plasminogen activator inhibitor, and angiotensin genes among others will be discussed. We will explore the nature, effects, and implications of the genetics that influence perioperative bleeding above and beyond surgical bleeding, particularly in cardiac surgery.