Aprotinin administration and pulmonary thromboembolism during orthotopic liver transplantation: report of two cases

Intracardiac thrombosis and pulmonary thromboembolism during liver transplantation: A systematic review and meta-analysis

Intracardiac thrombosis and/or pulmonary thromboembolism (ICT/PE) is a rare but devastating complication during liver transplantation. Its pathophysiology remains poorly understood, and successful treatment remains a challenge. This systematic review summarizes the available published clinical data regarding ICT/PE during liver transplantation. Databases were searched for all publications reporting on ICT/PE during liver transplantation. Data collected included its incidence, patient characteristics, the timing of diagnosis, treatment strategies, and patient outcomes. This review included 59 full-text citations. The point prevalence of ICT/PE was 1.42%. Thrombi were most often diagnosed during the neohepatic phase, particularly at allograft reperfusion. Intravenous heparin was effective in preventing early-stage thrombus from progressing further and restoring hemodynamics in 76.32% of patients it was utilized for; however, the addition of tissue plasminogen activator or sole use of tissue plasminogen activator offered diminishing returns. Despite all resuscitation efforts, the in-hospital mortality rate of an intraoperative ICT/PE was 40.42%, with nearly half of these patients dying intraoperatively. The results of our systematic review are an initial step for providing clinicians with data that can help identify higher-risk patients. The clinical implications of our results warrant the development of identification and management strategies for the timely and effective treatment of these tragic occurrences during liver transplantation.

Perioperative fatal pulmonary embolism in a pediatric liver transplant recipient

Patients with cirrhotic liver disease are in a state of fluctuating hemostatic balance. Hepatic synthetic dysfunction is commonly complicated by coagulation disorders that constitute an important parameter of most prognostic scores. The dominant feature of this dysfunction is bleeding tendencies, but cirrhotic patients may also exhibit inappropriate clotting and pro-coagulation placing them at risk for thromboembolism. We present a case of perioperative fatal pulmonary embolism in an 8-year-old patient with biliary cirrhosis secondary to drug-induced vanishing bile duct syndrome undergoing a deceased donor liver transplant. The massive pulmonary embolism occurred intra-operatively after reperfusion of the donor liver. Despite the initiation of extracorporeal membrane oxygenation, the postoperative course was complicated by bleeding and the patient expired. This unique case highlights the need for venous thromboembolism prevention by screening and prophylaxis prior to liver transplant in at least a subpopulation of pediatric patients. While the risk of thrombosis postoperatively in pediatrics patients is well known, the preoperative risk is less frequently described and deserves attention and practice changing action.

Significant Hyperfibrinolysis in a Patient With Intracardiac Thrombosis: To Give Antifibrinolytics or Not?

The hemostatic system is a delicate balance between the coagulation, anticoagulation, and fibrinolytic systems and is responsible for preventing both hemorrhage and thrombosis. End stage liver disease is characterized by a rebalanced hemostatic system that is fragile and easily tipped towards either hemorrhage or thrombosis. During an orthotopic liver transplantation, patients are exposed to a wide variety of factors that can shift them from a hypercoagulable state to a hypocoagulable state almost instantaneously. The treatment for these two disease states contradict each other, and therefore patients in this condition can be extremely difficult to manage. Here, we present a patient who underwent an orthotopic liver transplantation and suffered an intracardiac thrombosis shortly after reperfusion of the donor graft, that resolved with supportive care, who then went on to develop severe persistent hyperfibrinolysis and massive hemorrhage that was successfully treated with an antifibrinolytic agent.

Fibrinolysis in Living Donor Liver Transplantation Recipients Evaluated Using Thromboelastometry: Impact on Mortality

BACKGROUND

Inadequate hemostasis during living donor liver transplantation (LDLT) is mainly due to coagulopathy but may also include fibrinolysis. The purpose of this study was to determine the incidence of fibrinolysis and assess its relevance to mortality in LDLT.

METHODS

The incidence and prognosis of fibrinolysis were retrospectively studied in 76 patients who underwent LDLT between April 2010 and February 2013. Fibrinolysis was evaluated and defined by maximum lysis (ML) >15% within a 60-minute run time using thromboelastometry (ROTEM).

RESULTS

Fibrinolysis was observed in 19 of the 76 (25%) patients before the anhepatic (pre-anhepatic) phase and was developed in 24 (32%) patients during and after the anhepatic (post-anhepatic) phase. In these 43 patients who had fibrinolysis, spontaneous recovery occurred in 29 patients (73%) within 3 hours after reperfusion of the liver graft. Recovery with tranexamic acid was noted in 2 patients with fibrinolysis in the post-anhepatic phase. Thrombosis in the portal vein and liver artery was noted in 14 patients, and the incidence was significantly greater in patients with post-anhepatic fibrinolysis than in those with pre-anhepatic fibrinolysis (P = .0017). Fibrinolysis that developed in the pre-anhepatic phase was associated with increased 30-day and 6-month mortalities (P = .0003 and .0026, respectively).

CONCLUSIONS

Fibrinolysis existed and developed in a large percentage of patients during LDLT. Thrombosis in the portal vein and hepatic artery was more common in patients with fibrinolysis in the post-anhepatic phase. Fibrinolysis that developed in the pre-anhepatic phase was associated with increased 30-day and 6-month mortalities.

Perioperative thrombotic complications in liver transplantation

Although the perioperative bleeding complications and the major side effects of blood transfusion have always been the primary concern in liver transplantation (OLT), the possible cohesion of an underestimated intrinsic hypercoagulative state during and after the transplant procedure may pose a major threat to both patient and graft survival. Thromboembolism during OLT is characterized not only by a complex aetiology, but also by unpredictable onset and evolution of the disease. The initiation of a procoagulant process may be triggered by various factors, such as inflammation, venous stasis, ischemia-reperfusion injury, vascular clamping, anatomical and technical abnormalities, genetic factors, deficiency of profibrinolytic activity, and platelet activation. The involvement of the arterial system, intracardiac thrombosis, pulmonary emboli, portal vein thrombosis, and deep vein thrombosis, are among the most serious thrombotic events in the perioperative period. The rapid detection of occlusive vascular events is of paramount importance as it heavily influences the prognosis, particularly when these events occur intraoperatively or early after OLT. Regardless of the lack of studies and guidelines on anticoagulant prophylaxis in this setting, many institutions recommend such an approach especially in the subset of patients at high risk. However, the decision of when, how and in what doses to use the various chemical anticoagulants is still a difficult task, since there is no common consensus, even for high-risk cases. The risk of postoperative thromboembolism causing severe hemodynamic events, or even loss of graft function, must be weighed and compared with the risk of an important bleeding. In this article we briefly review the risk factors and the possible predictors of major thrombotic complications occurring in the perioperative period, as well as their incidence and clinical features. Moreover, the indications to pharmacological prophylaxis and the current treatment strategies are also summarized.

Anaesthesia for Living Related Liver Transplantation

With the greater success of liver transplantation, livers from deceased donors are insufficient to meet the need for livers required for transplantation. In various parts of Asia, living related liver transplantation is the treatment for patients with end-stage liver disease. An overview of anaesthesia for both the donor and the recipient is described. Controversies involving epidural anaesthesia, blood loss prevention and blood conservation techniques in the donor are discussed. Various aspects in the anaesthetic management of the recipient are also looked at.

Antifibrinolytics in liver surgery

Hyperfibrinolysis, a known complication of liver surgery and orthotopic liver transplantation (OLT), plays a significant role in blood loss. This fact justifies the use of antifibrinolytic drugs during these procedures. Two groups of drug namely lysine analogues [epsilon aminocaproic acid (EACA) and tranexamic acid (TA)] and serine-protease-inhibitors (aprotinin) are frequently used for this purpose. But uniform data or guidelines on the type of antifibrinolytic drugs to be used, their indications and correct dose, is still insufficient. Antifibrinolytics behave like a double-edged sword. On one hand, there are benefits of less transfusion requirements but on the other hand there is potential complication like thromboembolism, which has been reported in several studies. We performed a systematic search in PubMed and Cochrane Library, and we included studies wherein antifibrinolytic drugs (EACA, TA, or aprotinin) were compared with each other or with controls/placebo. We analysed factors like intraoperative red blood cell and fresh frozen plasma requirements, the perioperative incidence of hepatic artery thrombosis, venous thromboembolic events and mortality. Among the three drugs, EACA is least studied. Use of extensively studied drug like aprotinin has been restricted because of its side effects. Haemostatic effect of aprotinin and tranexamic acid has been comparable. However, proper patient selection and individualized treatment for each of them is required. Purpose of this review is to study various clinical trials on antifibrinolytic drugs and address the related issues like benefits claimed and associated potential complications.

Incidental intracardiac thromboemboli during liver transplantation: incidence, risk factors, and management

Even though numerous cases of massive thromboemboli have been reported in the literature, intracardiac thromboemboli (ICTs) incidentally found during orthotopic liver transplantation (OLT) have not been examined. In this study, we retrospectively examined the incidence, risk factors, and management of incidental ICTs during OLT. After institutional review board approval, adult patients who underwent OLT between January 2004 and December 2008 at our center were reviewed. ICTs were identified and confirmed by the examination of OLT datasheets, anesthesia records, and recorded transesophageal echocardiography (TEE) clips. The clinical presentation, management, and outcomes of the patients with ICTs were reviewed. Risk factors were analyzed by multivariate logistic regression. During the study period, 426 of the 936 adult OLT patients (45.5%) underwent intraoperative TEE monitoring. Incidental ICTs were identified in 8 of these 426 patients (1.9%). Two ICTs occurred before reperfusion, and 6 ICTs occurred after reperfusion. The treatment was at the discretion of the treating physicians; however, none of the patients received an anticoagulant or thrombolytics. Multivariate analysis identified 2 independent risk factors for intraoperative incidental ICTs: the presence of symptomatic or surgically treated portal hypertension (a history of gastrointestinal bleeding, a transjugular intrahepatic portosystemic shunt procedure, or portocaval shunt surgery) before OLT and intraoperative hemodialysis (odds ratios of 4.05 and 7.29, respectively; P < 0.05 for both). In conclusion, incidental ICTs during OLT occurred at a rate of 1.9% and were associated with several preoperative and intraoperative risk factors. The use of TEE allows early identification, which may be important. Our management for incidental ICTs is described; however, no conclusions can be made about the optimal therapy.

Requirements for transfusion and postoperative outcomes in orthotopic liver transplantation: A meta-analysis on aprotinin

AIM: To study the effect of aprotinin used in orthotopic liver transplantation (OLT) on the intraoperative requirement for blood products and on the incidence of laparotomy for bleeding, thrombotic events and mortality.

METHODS: A systematic review of the literature in the electronic database Medline and the Clinic Trials Registry Database was performed. Literature that did not fit our study were excluded. Patients in the reviewed studies were divided into two groups; one group used aprotinin (aprotinin group) while the other did not (control group). The data in the literature that fit our requirements were recorded. Weighted mean differences (WMD) in the requirements for blood products between the aprotinin group and the control group were tested using a fixed effect model. A Z test was performed to examine their reliability; the Fleiss method of fixed effect model was used to analyze data on postoperative events, and odds ratios (ORs) were tested and merged.

RESULTS: Seven citations were examined in our study. Among them, a requirement for blood products was reported in 4 studies including 321 patients, while postoperative events were reported in 5 studies including 477 patients. The requirement for red blood cells and fresh frozen plasma in the aprotinin group was statistically lower than that in the control group (WMD = -1.80 units, 95% CI, -3.38 to -0.22; WMD = -3.99 units, 95% CI, -6.47 to -1.50, respectively). However, no significant difference was indicated in the incidence of laparotomy for bleeding, thrombotic events and mortality between the two groups. Analysis on blood loss, anaphylactic reactions and renal function was not performed in this study due to a lack of sufficient information.

CONCLUSION: Aprotinin can reduce the intraoperative requirement for blood products in OLT, and has no significant effect on the incidence of laparotomy for bleeding, thrombotic events and mortality.

Intraoperative pulmonary embolism and intracardiac thrombosis complicating liver transplantation: a systematic review

BACKGROUND

Pulmonary embolism (PE) and intracardiac thrombosis (ICT) are rare but potentially lethal complications during orthotopic liver transplantation (OLT).

METHODS

We aimed to review clinical and pathological correlates of PE and ICT in patients undergoing OLT. A systematic review of the literature was conducted using MEDLINE and ISI Web of Science.

RESULTS

Seventy-four cases of intraoperative PE and/or ICT were identified; PE alone in 32 patients (43%) and a combination of PE and ICT in 42 patients (57%). Most frequent clinical symptoms included systemic hypotension and concomitant rising pulmonary artery pressure, often leading to complete circulatory collapse. PE and ICT occurred in every stage of the operation and were reported equally in patients with or without the use of venovenous bypass or antifibrinolytics. A large variety of putative risk factors have been suggested in the literature, including the use of pulmonary artery catheters or certain blood products. Nineteen patients underwent urgent thrombectomy or thrombolysis. Overall mortality was 68% (50/74) and 41 patients (82%) died intraoperatively.

CONCLUSION

Mortality was significantly higher in patients with an isolated PE, compared to patients with a combination of PE and ICT (91% and 50%, respectively; P < 0.001). Intraoperative PE and ICT during OLT appear to have multiple etiologies and may occur unexpectedly at any time during the procedure.

Efficacy and safety of antifibrinolytic drugs in liver transplantation: a systematic review and meta-analysis

Although several randomized controlled trials (RCTs) have shown the efficacy of antifibrinolytic drugs in liver transplantation, their use remains debated due to concern for thromboembolic complications. None of the reported RCTs has shown a higher incidence of these complications in treated patients; however, none of the individual studies has been large enough to elucidate this issue completely. We therefore performed a systematic review and meta-analysis of efficacy and safety endpoints in all published controlled clinical trials on the use of antifibrinolytic drugs in liver transplantation. Studies were included if antifibrinolytic drugs (epsilon-aminocaproic acid, tranexamic acid (TA) or aprotinin) were compared with each other or with controls/placebo. Intraoperative red blood cell and fresh frozen plasma requirements, the perioperative incidence of hepatic artery thrombosis, venous thromboembolic events and mortality were analyzed. We identified 23 studies with a total of 1407 patients which met the inclusion criteria. Aprotinin and TA both reduced transfusion requirements compared with controls. No increased risk for hepatic artery thrombosis, venous thromboembolic events or perioperative mortality was observed for any of the investigated drugs. This systematic review and meta-analysis does not provide evidence for an increased risk of thromboembolic events associated with antifibrinolytic drugs in liver transplantation.

Cardiovascular collapse due to massive pulmonary thromboembolism during orthotopic liver transplantation

Severe pulmonary thromboembolism has been occasionally reported during orthotopic liver transplantation, with fatal outcomes occurring in about 50% of cases because of low cardiac output and multiple organ failure. Perioperative alterations in coagulation, insertion of pulmonary artery and other invasive catheters, administration of antifibrinolytic agents, and repeated ischemic insults may all promote the formation of intravascular/cardiac blood clots. We present a case of intraoperative right ventricular failure associated with the presence of a large thrombus wrapped around the pulmonary artery catheter. Identification of risk factors for intraoperative pulmonary thromboembolism warrants a prophylactic medical approach including selective blood component therapy and administration of antifibrinolytics guided by bedside coagulation tests as well as noninvasive hemodynamic monitoring.

Fatal pulmonary microthrombi during surgical therapy for end-stage heart failure: Possible association with antifibrinolytic therapy

BACKGROUND

Maintaining hemostasis in patients with end-stage heart failure undergoing cardiac surgery is always challenging. These patients have chronic hepatic insufficiency, resulting in derangement of coagulation. In addition, they are commonly receiving both systemic anticoagulation (warfarin or heparin) and antiplatelet therapy. The introduction of antifibrinolytics has had a significant effect on postoperative coagulopathy. We report fatal pulmonary microthrombi in patients receiving antifibrinolytics who developed suprasystemic pulmonary artery pressures and right heart failure that was impossible to overcome despite insertion of a right ventricular assist device.

METHODS

We reviewed the surgical procedure and autopsy reports to identify patients with high pulmonary artery pressures caused by pulmonary microthrombi after a cardiac surgical procedure for end-stage heart failure. Patient demographics and preoperative, intraoperative, and postoperative variables were collected from a retrospective review of the patients' medical records.

RESULTS

We identified 9 patients (7 men and 2 women; mean age, 45 +/- 16 years) who died of pulmonary microthrombi after cardiac surgery between January 1997 and January 2004. Surgical procedures included 5 left ventricular assist device implantations, 2 heart transplantations, and 2 left ventricular reconstructions with mitral valve repair or replacement. Eight patients received aprotinin, and 1 patient received epsilon-aminocaproic acid immediately before and during cardiopulmonary bypass. All patients had severe suprasystemic pulmonary artery pressures after protamine administration for heparin reversal, a complication that proved fatal in all cases. Intraoperative wedge biopsy of the lungs revealed multiple microthrombi within capillaries and in the small- and medium-sized pulmonary arterioles.

CONCLUSION

We report 9 cases for which fatal pulmonary microthrombi might be associated with the use of prophylactic antifibrinolytic therapy. Mortally ill patients with multiorgan failure who are receiving systemic anticoagulation and undergoing surgical procedures require careful perioperative monitoring to identify potential hazards. Anticoagulation and antifibrinolytic therapy protocols may require adjustment in such patients.

Comparison of the effects of aprotinin and tranexamic acid on blood loss and red blood cell transfusion requirements during the late stages of liver transplantation

BACKGROUND

During liver transplantation (LT), profound activation of the fibrinolytic system can contribute significantly to perioperative bleeding. Prophylactic administration of antifibrinolytic agents has been shown to reduce blood loss and the need for allogeneic transfusion in these conditions.

STUDY DESIGN AND METHODS

This prospective randomized trial included 51 cirrhotic patients undergoing LT. Patients were randomly assigned to receive either 280 mg of aprotinin (AP) followed by 70 mg per hour or 40 mg per kg tranexamic acid (TA) followed by 40 mg per kg per hour, administered from the end of the anhepatic phase until 2 hours after reperfusion of the graft, and the effects on blood loss and red blood cell (RBC) transfusion requirements were compared. Transfusion policy was standardized in all patients. In addition, the biological effects of the two drugs, as assessed by coagulation and fibrinolytic markers obtained during surgery, were evaluated in a subgroup of patients from each treatment group and compared with an historical control group that did not receive antifibrinolytic drugs.

RESULTS

There was no significant difference between the two groups in perioperative blood losses (AP, 6200 [4620-8735] mL; TA, 5945 [4495-8527] mL; median [range]) or in RBC transfusions requirements (AP, 9 [6.75-15.25] units; TA, 10 [6.5-13.5] units). Inhibition of fibrinolysis was observed with both drugs compared with the control group. Coagulation appeared to be activated more with AP, however, whereas fibrinolysis was inhibited more by TA.

CONCLUSION

Blood losses and RBC transfusion requirements were comparable regardless of the drug administered. TA may be as valuable as AP for controlling fibrinolysis in LT.

Successful intraoperative use of recombinant tissue plasminogen activator during liver transplantation complicated by massive intracardiac/pulmonary thrombosis

During orthotopic liver transplantation a patient received epsilon-aminocaproic acid and clotting factors. Shortly after hepatic artery clamping the patient developed a massive intracardiac/intravascular thrombosis that resulted in cardiac arrest. After diagnosis by transesophageal echocardiography, the patient was treated with recombinant tissue plasminogen activator through a central venous catheter advanced into the right atrium. After treatment with recombinant tissue plasminogen activator, the patient's hemodynamic status improved, permitting the liver transplant to be completed. The patient was ultimately discharged to home. We report the successful intraoperative resuscitation of a patient with acute intracardiac/intravascular thrombosis during an orthotopic liver transplantation using thrombolytic therapy.

Cardiopulmonary bypass and mitral valve replacement during pregnancy

Gravid patient cardiopulmonary bypass remains a high-risk procedure with regard to fetal preservation. Maternal mortality is similar to that of the nonpregnant female at 1.5-5%. However, fetal mortality remains high at 16-33%, with an average of 19% over the past 25 years, with no correlation to gestational age. Teratogenesis is a major consideration in the first trimester. Variations in the timing of surgical intervention, gestational age, maternal health status, type of procedure, pre- or postorganogenesis, perfusion protocol, and pharmaceutical therapy are all factors that can influence fetomaternal outcome. In this report, we present a literature review along with our experience of a 26-year-old female who developed complications with her pregnancy at approximately 17 weeks gestation, with adverse neurological sequelae. The patient was 152 cm in height and weighed 48 kg, with a calculated body surface area of 1.40 M2. She had no prior history of cardiac disease and, upon admission to our institution, presented with a declining health status in pulmonary edema and was treated medically, with an ultimate requirement for mitral valve replacement. The total cardiopulmonary bypass time was 99 min with an aortic crossclamp time of 83 min. The literature, as expected, is limited to case reports and reviews since a controlled clinical trial during pregnancy is nonexistent, using extracorporeal circulation. This greatly challenges the medical staff in managing such difficult cases, with an incidence of heart disease during pregnancy of 1.2-3.7%.

Four cases of cardiopulmonary thromboembolism during liver transplantation without the use of antifibrinolytic drugs

Orthotopic liver transplantation (OLT) is one of the most demanding surgical procedures performed. Intraoperative bleeding can be substantial and related to both surgical and nonsurgical causes. A less common but previously reported phenomenon is intraoperative cardiopulmonary thromboembolism precipitating major patient morbidity and mortality. In this paper, we present four cases of intraoperative thromboembolism during OLT. These cases were performed without the concomitant use of antifibrinolytic drugs. We performed a review and analysis of previously reported cases of intraoperative thromboembolism during OLT. Possible causes of thromboembolism, clinical management, use of thromboelastography, and the role of antifibrinolytic drugs are discussed.

A review of aprotinin in orthotopic liver transplantation: can its harmful effects offset its beneficial effects?

Blood transfusion can adversely affect patient outcome and graft survival in orthotopic liver transplantation (OLT). With this respect, prophylactic aprotinin administration decreases blood loss, transfusion requirements, and the hemodynamic changes associated with graft reperfusion in patients undergoing OLT. However, data indicate limiting the use of aprotinin in OLT: (a) clinical, biological, echocardiographic, and postmortem findings recorded in patients with chronic liver disease or undergoing OLT suggest that a continuous prothrombotic state exists in these patients. Whether the inhibition of fibrinolysis associated with aprotinin therapy will expose some patients to untoward thrombosis is questionable; (b) aprotinin does not appear to alter postoperative outcome in patients undergoing OLT; (c) aprotinin decreases blood transfusion requirements only when surgery is associated with significant blood loss. However, at the present time, median transfusion requirements of 2 to 5 red blood cell units are required in OLT.

Antifibrinolytics in orthotopic liver transplantation: current status and controversies

This article reviews the current status and controversies of the 3 commonly used antifibrinolytics-epsilon-aminocaproic acid, tranexamic acid and aprotinin-during liver transplantation. There is no general consensus on how, when or which antifibrinolytics should be used in liver transplantation. Although these drugs appear to reduce blood loss and decrease transfusion requirements during liver transplantation, their use is not supported uniformly in clinical trials. Aprotinin has been studied more extensively in clinical trials and appear to offer more advantages compared to two other antifibrinolytics. Because of the diverse population of liver transplant recipients and the potential adverse effects of antifibrinolytics, especially life-threatening thromboembolism, careful patient selection and close monitoring is prudent. Further studies addressing the risks and benefits of antifibrinolytics in the setting of liver transplantation are warranted.

Aprotinin and major orthopedic surgery

Aprotinin is a potent pharmacological agent that reduces bleeding and limits blood transfusion requirements in current surgical practice. Many studies have been conducted in orthopedic surgery. In several trials performed in total hip replacement (THR) and total knee replacement (TKN) patients, aprotinin only moderately decreased blood-loss-replacement requirements. Conversely, when aprotinin was used in patients at high risk for bleeding (cancer, sepsis, redone surgery), it developed a potent hemostatic activity and decreased blood transfusion significantly. No increase in deep vein thrombosis and pulmonary embolism was observed. The only major side effect could be the potential occurrence of an anaphylactoid reaction. Prophylactic administration of aprotinin should be considered in extensive spine surgery and in high-risk major orthopedic operations. The decision to use aprotinin should be guided by a risk/benefit analysis.

Diagnosis and Treatment of Intracardiac Thrombosis During Orthotopic Liver Transplantation

Intracardiac thrombus formation during orthotopic liver transplantation can be a catastrophic event leading to death. Most often this devastating complication occurs after reperfusion and may be related to massive blood transfusion, marginal liver grafts, tendencies towards hypercoagulability, or the potential role of antifibrinolytics. We report a case of an intracardiac thrombus occurring during the hepatectomy stage (stage I) of orthotopic liver transplantation. Transesophageal echocardiography was used to quickly diagnose the thrombus, allowing rapid pharmacological intervention and later guide surgical evacuation of the intracardiac thrombus via the inferior vena cava.

A direct antifibrinolytic agent in major orthopedic surgery

Aprotinin is a potent pharmacological agent that reduces bleeding. In current surgical practices, the rate of blood transfusions has decreased with the use of aprotinin. Recently, studies using aprotinin have been conducted in orthopedic surgery. Several trials have been performed in patients undergoing total hip replacement and total knee replacement. Aprotinin moderately decreased blood loss in these patients. When aprotinin was used in patients with a high-risk of bleeding (ie, patients with cancer, sepsis, or undergoing reoperation), potent hemostatic activity occurred and the rate of blood transfusions significantly decreased. No increase in deep vein thrombosis and pulmonary embolism was observed. One adverse effect was the potential occurrence of an anaphylactoid reaction. Prophylactic administration of aprotinin should be considered in extensive spine surgery and in high-risk orthopedic operations. The decision to use aprotinin can be guided by a risk/benefit analysis.

Intravascular thrombosis and thromboembolism during liver transplantation: antifibrinolytic therapy implicated?

This case report describes a patient who underwent orthotopic liver transplantation and developed extensive hyperacute venous and arterial intravascular thromboses and thromboemboli intraoperatively. The patient was receiving antifibrinolytic therapy with aprotinin. The safety of routine aprotinin therapy in liver transplantation is examined. The value of the thrombelastograph (TEG) as a qualitative assessment of the coagulation system is emphasized.

Pharmacological strategies to decrease transfusion requirements in patients undergoing surgery

Surgical procedures are inevitably associated with bleeding. The amount of blood loss may vary widely between different surgical procedures and depends on surgical as well as non-surgical factors. Whereas adequate surgical haemostasis may suffice in most patients, pro-haemostatic pharmacological agents may be of additional benefit in patients with (diffuse) surgical bleeding or in patients with a specific underlying haemostatic defect. In general, surgical haemostasis and pharmacological therapies can be complementary in controlling blood loss. The use of pharmacological therapies to reduce blood loss and blood transfusions in surgery has historically been restricted to a few drugs. Antifibrinolytic agents (aprotinin, tranexamic acid and aminocaproic acid) have the best evidence supporting their use, especially in cardiac surgery, liver transplantation and some orthopaedic surgical procedures. Meta-analyses of randomised, controlled trials in cardiac patients have suggested a slight benefit of aprotinin, compared with the other antifibrinolytics. Desmopressin is the treatment of choice in patients with mild haemophilia A and von Willebrand disease. It has also been shown to be effective in patients undergoing cardiac surgery who received aspirin up to the time of operation. However, overall evidence does not support a beneficial effect of desmopressin in patients without pre-existing coagulopathy undergoing elective surgical procedures. Topical agents, such as fibrin sealants have been successfully used in a variety of surgical procedures. However, only very few controlled clinical trials have been performed and scientific evidence supporting their use is still limited. Novel drugs, like recombinant factor VIIa (eptacog alfa), are currently under clinical investigation. Recombinant factor VIIa has been introduced for the treatment of haemophilia patients with inhibitors, either in surgical or non-surgical situations. Preliminary data indicate that it may also be effective in surgical patients without pre-existing coagulation abnormalities. More clinical trials are warranted before definitive conclusions can be drawn about the safety and the exact role of this new drug in surgical patients. Only adequately powered and properly designed randomised, clinical trials will allow us to define the most effective and the safest pharmacological therapies for reducing blood loss and transfusion requirements in surgical patients. Future trials should also consider cost-effectiveness because of considerable differences in the costs of the available pro-haemostatic pharmacological agents.

Aprotinin versus placebo in major orthopedic surgery: a randomized, double-blinded, dose-ranging study

We conducted a prospective, multicenter, double-blinded, dose-ranging study to compare the risk/benefit ratio of large- and small-dose aprotinin with placebo after major orthopedic surgery. Fifty-eight patients were randomized into three groups: Large-Dose Aprotinin (4 M kallikrein inactivator unit [KIU] bolus before surgery followed by a continuous infusion of 1 M KIU/h until the end of surgery), Small-Dose Aprotinin (2 M KIU bolus plus 0.5 M KIU/h), and Placebo. Bleeding was measured and calculated. Bilateral ascending venography was systematically performed on the third postoperative day. Measured and calculated blood loss decreased in the Large-Dose Aprotinin group (calculated bleeding, whole blood, hematocrit 30%, median [range], 2,023 mL [633-4,113] as compared with placebo, 3,577 mL [1,670-21,758 mL]). The total number of homologous and autologous units was also significantly decreased in the Large-Dose Aprotinin group (2 U [0-5 U] as compared with placebo, 4 U [0-42 U]). No increase in deep vein thrombosis or pulmonary embolism was observed in the aprotinin groups. Large-dose aprotinin was safe and effective in dramatically reducing the measured and calculated bleeding and the amount of transfused red blood cell units after major orthopedic surgery.

IMPLICATIONS

Large doses of aprotinin decrease blood loss and transfusion amount in major orthopedic surgery.