Aprotinin Decreases Postoperative Bleeding and Number of Transfusions in Patients on Clopidogrel Undergoing Coronary Artery Bypass Graft Surgery

Platelet function testing and prediction of procedural bleeding risk

The essential role of platelets in haemostasis underlies the relationship between platelet function and spontaneous or procedure-related bleeding, which has important prognostic implications. Although not routinely undertaken, platelet function testing offers the potential to tailor antiplatelet therapy for individual patients. However, uncertainties remain about how well platelet function testing may predict haemostasis and guide management of bleeding risk. Studies of aspirin, P2Y12 inhibitors and other antiplatelet drugs clearly demonstrate how inhibition of platelet function increases bleeding risk. More potent antiplatelet drugs are associated with higher bleeding rates, consistent with the levels of platelet inhibition achieved by these drugs. Studies of patients treated with clopidogrel, which is associated with wide inter-individual variation in antiplatelet effect, suggest that platelet function testing may predict bleeding risk related to coronary artery bypass grafting (CABG) surgery and potentially guide the timing of surgery following discontinuation of clopidogrel. Similarly, some studies have demonstrated a relationship between clopidogrel response and bleeding in patients undergoing percutaneous coronary intervention (PCI), although other studies have not supported this. Carriage of the *17 allele of cytochrome P450 2C19, which is associated with gain of function and enhanced response to clopidogrel, seems to be associated with increased bleeding risk, although studies showing lack of apparent effect of loss-of-function alleles provide contradictory evidence. Further large studies are needed to guide best practice in the application of platelet function testing in the clinical management of patients treated with antiplatelet drugs in order to optimise individual care.

Strategies for blood conservation in pediatric cardiac surgery

Cardiac surgery accounts for the majority of blood transfusions in a hospital. Blood transfusion has been associated with complications and major adverse events after cardiac surgery. Compared to adults it is more difficult to avoid blood transfusion in children after cardiac surgery. This article takes into account the challenges and emphasizes on the various strategies that could be implemented, to conserve blood during pediatric cardiac surgery.

Is early hip fracture surgery safe for patients on clopidogrel? Systematic review, meta-analysis and meta-regression

INTRODUCTION

Hip fracture is a common presentation in the elderly population, many of whom will be taking the antiplatelet clopidogrel, which has the potential to increase perioperative bleeding. The aim of this systematic review and meta-analysis was to answer the questions: (1) is early hip fracture surgery for patients on clopidogrel associated with worse postoperative outcomes compared to patients not on clopidogrel? (2) is early versus delayed surgery for these patients associated with worse postoperative outcomes?

METHODS

A systematic search was conducted of MEDLINE, EMBASE, Cinahl and AMED databases. Results from patients undergoing early surgery on clopidogrel were compared to a control group not taking clopidogrel. In addition, patients taking clopidogrel undergoing early and delayed surgery were compared.

RESULTS

For patients taking clopidogrel undergoing early surgery, there was no associated increase in overall mortality (OR 0.89; 95% CI: 0.58-1.38) or 30-day mortality (OR 1.10 95% CI: 0.48-2.54). However, there was an associated increase in blood transfusion (OR 1.41 95% CI: 1.00-1.99). There was an associated decreased length of stay in the early surgery versus delayed surgery group (weighted mean difference -7.09 days (95% CI: -10.14 to -4.04).

DISCUSSION

Early surgery appears safe for patients with hip fracture though there may be a small increase in the rate of blood transfusion. However, larger prospective trials are required to confirm these findings.

Aprotinin in cardiac surgery

Aprotinin is a naturally occurring serine protease inhibitor that is being used with increasing frequency in cardiac surgery and beyond to reduce blood loss and the need for perioperative blood transfusion. Through inhibition of serine proteases such as plasmin, aprotinin significantly reduces fibrinolysis, thereby aiding hemostasis during surgical procedures. In addition, aprotinin interacts with other factors in the coagulation and fibrinolytic cascade, creating a hemostatic balance, without increasing the risk of thrombosis. These proven benefits are supplemented by the anti-inflammatory properties of aprotinin, which may help curb some of the deleterious effects of cardiopulmonary bypass. This article will review the discovery of aprotinin, its mechanism of action, dosing and adverse effects, and highlight the major recent trials demonstrating its efficacy.

Managing adverse effects and drug-drug interactions of antiplatelet agents

Antiplatelet therapies have reduced the frequency of adverse events associated with plaque rupture in several clinical situations. These therapies include established antiplatelet agents (such as aspirin, clopidogrel, or glycoprotein IIb/IIIa inhibitors) as well as new agents (such as prasugrel and ticagrelor). In this Review, we address the most important adverse events of antiplatelet therapy, including hemorrhage, hematologic reactions, and dyspnea. We discuss strategies to reduce the incidence of complications and outline potential methods to manage adverse reactions. Interactions between antiplatelet agents and other drugs--such as proton-pump inhibitors, calcium-channel blockers, statins, warfarin, or NSAIDs--are also addressed, as well as specific issues relating to the use of antiplatelet therapies in elderly patients.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. This version of the review includes a sensitivity analysis excluding trials authored by Prof. Joachim Boldt.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

The Management of Antiplatelet Therapy in Patients With Coronary Stents Undergoing Noncardiac Surgery

Whereas the development of coronary stents has been a major breakthrough in the treatment of coronary artery disease, stent thrombosis, associated with myocardial infarction and death, has introduced a new challenge in the care of patients with coronary stents undergoing noncardiac surgery. This review presents the authors’ recommendations regarding the optimal management of such patients. Elective surgery should be postponed for at least 6 weeks and optimally 3 months for a bare-metal stent and at least 1 year for a drug-eluting stent. On the other hand, managing a patient undergoing non-elective surgery is more difficult and necessitates a case-by-case assessment of bleeding risk versus thrombotic risk based on patient comorbidities, type of stents present, details of the coronary intervention, and type of surgical procedure. Patients with a risk of bleeding that outweighs the risk of stent thrombosis should discontinue at least clopidogrel, whereas all other patients should continue dual antiplatelet therapy throughout the perioperative period.

Perioperative handling of patients on antiplatelet therapy with need for surgery

The widespread use of metal stents and drug-eluting stents has shown the extent to which patients with unstable coronary perfusion depend on antiplatelet drugs, and how their risk of late thrombosis depends on the long-term use of agents such as clopidogrel. It has also been shown that the risk of surgical bleeding, if antiplatelet drugs are continued, is lower than that of coronary thrombosis if they are withdrawn. Thus, except for low-risk settings, the practice of withdrawing antiplatelet drugs 5-10 days prior to surgical procedures should be changed. The following suggestions are meant to provide a guideline in this respect. Most of the current surgical procedures may be performed while on low-dose aspirin treatment. Except when bleeding may occur in closed spaces (e.g. intracranial surgery, spinal surgery in the medullary canal, surgery of the posterior chamber of the eye) or where excessive blood loss is expected, where only clopidogrel should be discontinued; in all other cases the surgical procedures should be carried out in the presence of dual antiplatelet agents (if prescribed). Aspirin may be discontinued only in subjects at low risk of thrombosis, and at high risk of intraoperative bleeding. Operations associated with an expected excessive blood loss should be postponed unless vital. When prescribed for acute coronary syndrome or during stent re-endothelialization, clopidogrel should not be discontinued before a noncardiac procedure. For elective procedures, surgery should be postponed until the end of the indication for clopidogrel. After the operation, clopidogrel should be resumed within the 12-24 h. Cardiac procedures should be postponed for at least 4 days after clopidogrel withdrawal. The thrombotic risk of preoperative withdrawal of antiplatelet drugs overwhelms the benefit of regional or neuraxial blockade. Antiplatelet treatment replacement by heparin or low-molecular weight heparin does not provide protection against the risk of coronary artery or stent thrombosis. Haemostasis requires that at least 20% of circulating platelets have a normal function. As the effects of antiplatelet agents are not reversible by other drugs, fresh platelets are the only manner to rapidly restore normal haemostasis. Aprotinin decreases postoperative bleeding and transfusion rates in patients undergoing CABG and on clopidogrel during the days preceding surgery.

Recent advances in the management of coronary artery disease: highlights from the literature

The recent advances in the multidisciplinary management of coronary artery disease (CAD) have been significant. The assessment of patients before percutaneous coronary intervention is likely to change significantly. National compliance with clinical guidelines in the preprocedural assessment of myocardial ischemia should be encouraged. Multislice computed tomographic coronary angiography continues to improve and is already an excellent screening test for CAD. Coronary stenting has an increasing role in multivessel and left main CAD, although further outcome trials are indicated, especially in the elderly. Although off-pump coronary artery bypass graft (CABG) surgery reduces postoperative atrial fibrillation, further major outcome advantages have not been shown in comprehensive meta-analyses when compared with on-pump CABG surgery. Although an intra-aortic balloon pump reduces mortality in high-risk CABG surgery, it may be replaced gradually by the percutaneous left ventricular-assist device, which has shown clinical benefit in this challenging setting. Statin therapy significantly improves clinical outcome after CABG surgery, even when begun postoperatively. There is strong evidence that, unless contraindicated, all CABG patients should receive statin therapy. Clopidogrel therapy just before CABG surgery is still associated with prolonged hospital stay because of significant bleeding complications. This risk will be exacerbated with the advent of the more potent platelet inhibitor, prasugrel. There is a clinical necessity for readily reversible platelet blockade to minimize the bleeding risks in CABG surgery.

A survey of the peri-operative management of urological patients on clopidogrel

INTRODUCTION

Peri-operative management of patients receiving platelet inhibitors, such as clopidogrel presents a dilemma to surgeons in every surgical specialty including urology. The risk of procedure-related bleeding while continuing clopidogrel needs to be weighed against the risk of thrombo-embolism after discontinuing it. The objective of the survey was to determine current UK practice regarding clopidogrel use/cessation in patients undergoing elective urological procedures.

SUBJECTS AND METHODS

A 10-part questionnaire relating to pre- and postoperative clopidogrel use was mailed to all UK urology consultants listed in the British Association of Urological Surgeons' directory.

RESULTS

A total of 570 questionnaires were sent and 297 (52%) were returned. The majority of respondents stop clopidogrel prior to TUR surgery (96.6%), major urological surgery (91.7%), TRUS biopsy (90.6%), ESWL (81.8%) and cystoscopy and biopsy (70.1%). The time clopidogrel was stopped pre-operatively and restarted postoperatively was very variable and dependent on local guidelines or urologist preference. Almost half (49.5%) of the respondents would stop clopidogrel irrespective of its indication and 40.7% never consulted a cardiologist/haematologist before stopping clopidogrel. Less than half (43.4%) had a protocol/guideline in place concerning stopping clopidogrel before surgery. Of respondents, 43% do not routinely prescribe bridging therapy after discontinuing clopidogrel. Over half (55%) reported bleeding complications in patients who continued their clopidogrel during urological procedures and 22 (7.4%) of respondents reported an adverse thrombo-embolic event after stopping clopidogrel. The vast majority of respondents (92.8%) felt evidence-based guidelines on clopidogrel use during the peri-operative period would be useful.

CONCLUSIONS

This survey has highlighted a significant variation in practice with regards to pre- and postoperative management of clopidogrel in patients undergoing urological procedures. The results of this survey highlight the need for evidence-based guidelines for the peri-operative management of patients on clopidogrel.

Management and outcome of peptic ulcers or erosions in patients receiving a combination of aspirin plus clopidogrel

BACKGROUND

This multicenter retrospective study investigated the management and outcome of patients with peptic ulcer/erosion-related aspirin and clopidogrel (A + C) cotherapy.

METHODS

From January 2002 to September 2006, patients with endoscopically proven peptic ulcers/erosions after receiving A + C cotherapy were analyzed.

RESULTS

This group consisted of 106 patients (age, 69.3 +/- 11.7 years). Ulcers/erosions developed in 27 patients during hospitalization for cardiac events and in 79 patients after hospital discharge. Of 27 patients hospitalized for acute cardiac events, gastrointestinal (GI) bleeding and dyspepsia occurred in 24 and three, respectively. The most common lesion was gastric ulcer. Of 79 discharged patients, GI bleeding and dyspepsia occurred in 64 and 15, respectively. The most common bleeding and dyspeptic lesions were gastric ulcer and gastritis, respectively. Overall, 17 patients underwent endoscopic hemostasis all successfully. A + C cotherapy was continued in 57 patients for a median (interquartile range) of 3.0 (6.2) months. Most were coprescribed a proton pump inhibitor (PPI) (53, 93%). No recurrent GI bleeding was observed.

CONCLUSIONS

After A + C cotherapy, gastric ulcer or gastritis were the most common endoscopic lesions. The combination of a PPI and endoscopic treatment for ulcer bleeding was highly successful. After patient stabilization, continuation of A + C cotherapy with a PPI appears to be safe.

Aprotinin during coronary-artery bypass grafting and risk of death

BACKGROUND

Aprotinin (Trasylol) is used to mitigate bleeding during coronary-artery bypass grafting (CABG). Accumulating evidence suggests that this practice increases mortality.

METHODS

Using electronic administrative records of the Premier Perspective Comparative Database, we studied hospitalized patients with operating-room charges for the use of aprotinin (33,517 patients) or aminocaproic acid (44,682 patients) on the day CABG was performed. We tabulated the numbers of patients with a hospital-discharge status of death and performed three types of analyses: a multivariable logistic-regression analysis (primary analysis); propensity-score matching in the highly selected subcohort of patients who received full amounts of the study drug, who underwent CABG by surgeons who performed 50 or more CABG surgeries during the study period, and for whom information on 10 additional covariates was available because the surgery occurred on hospital day 3 or later; and an instrumental-variable analysis of data from patients whose surgeons showed a strong preference for one of the two study drugs.

RESULTS

In all, 1512 of the 33,517 aprotinin recipients (4.5%) and 1101 of the 44,682 aminocaproic acid recipients (2.5%) died. After adjustment for 41 characteristics of patients and hospitals, the estimated risk of death was 64% higher in the aprotinin group than in the aminocaproic acid group (relative risk, 1.64; 95% confidence interval [CI], 1.50 to 1.78). In the first 7 days after surgery, the adjusted relative risk of in-hospital death in the aprotinin group was 1.78 (95% CI, 1.56 to 2.02). The relative risk in a propensity-score-matched analysis was 1.32 (95% CI, 1.08 to 1.63). In the instrumental-variable analysis, the use of aprotinin was found to be associated with an excess risk of death of 1.59 per 100 patients (95% CI, 0.14 to 3.04). Postoperative revascularization and dialysis were more frequent among recipients of aprotinin than among recipients of aminocaproic acid.

CONCLUSIONS

Patients who received aprotinin alone on the day of CABG surgery had a higher mortality than patients who received aminocaproic acid alone. Characteristics of neither the patients nor the surgeons explain the difference, which persisted through several approaches to control confounding.

Effect of aprotinin on renal dysfunction in patients undergoing on-pump and off-pump cardiac surgery: a retrospective observational study

BACKGROUND

Aprotinin is used during cardiac surgery for its blood-saving effects. However, reports suggest a possible association between use of this drug and increased renal dysfunction and mortality. We investigated the effect of aprotinin on renal dysfunction in cardiac surgery, considering the cofactors on-pump versus off-pump surgery and co-medication with angiotensin-converting enzyme (ACE) inhibitors.

METHODS

Our analysis included 9875 patients undergoing on-pump or off-pump cardiac surgery from Jan 1, 2000, to Sept 30, 2007. Of these patients, 9106 were included in the retrospective observational study analysis. With propensity-adjusted, multivariate staged logistic regression, we analysed separately the incidence of renal dysfunction in patients receiving aprotinin, tranexamic acid, or no antifibrinolytic treatment in the presence or absence of preoperative ACE inhibitor treatment, for both on-pump and off-pump surgical techniques.

FINDINGS

In 5434 patients undergoing on-pump cardiac surgery, the odds ratio (OR) between aprotinin and an increased risk of renal dysfunction without ACE inhibitor was 1.81 (95% CI 0.79-4.13, p=0.162) and with ACE inhibitor 1.73 (0.56-5.32, p=0.342). In the 848 patients taking ACE inhibitors and undergoing off-pump cardiac surgery, aprotinin was associated with a greater than two-fold increase in the risk of renal dysfunction after off-pump cardiac surgery (OR 2.87 [1.25-6.58], p=0.013).

INTERPRETATION

Our results have shown that aprotinin seems to be safe during on-pump cardiac surgery. However, the combination of aprotinin and ACE inhibitors during off-pump cardiac surgery is associated with a significant risk of postoperative renal dysfunction.

Aortic valve replacement in a young patient with essential thrombocytosis

Essential Thrombocythcythaemia (ET) is an uncommon type of myeloproliferative disorder, characterised by both thrombotic and haemorrhagic diathesis. No clear guidelines exist for the pre- and post-operative management of patients undergoing cardiac surgery in the haematological and surgical literature. This condition has profound implications in patients undergoing cardiac surgery with the use of cardiopulmonary bypass, where heparin is used for anti-coagulation. This dilemma is further compounded in the setting of a young patient undergoing aortic valve replacement (AVR), where insertion of a mechanical prosthesis would be the procedure of choice. This would require life-long anticoagulation with warfarin which can predispose these patients to catastrophic bleeding. Using a tissue valve will subject the patient to multiple redo operations in the patient's lifetime. We report a young patient with ET requiring AVR and discuss the dilemmas surrounding the choice of prosthesis in this patient.

Antifibrinolytic use in adult cardiac surgery

PURPOSE OF REVIEW

Antifibrinolytics are used to attenuate the coagulopathy associated with cardiopulmonary bypass. However, recent studies suggest that the antifibrinolytic aprotinin is associated with increased renal and vascular events and death compared to its alternatives. To develop a recommendation for antifibrinolytic use in adult cardiac surgery, we performed a systematic review and meta-analysis to determine the association of the antifibrinolytics with efficacy, safety and cost outcomes.

RECENT FINDINGS

Aprotinin, when compared to placebo, significantly decreased blood transfusions and reoperations for bleeding, strokes and cognitive dysfunction, and significantly increased renal dysfunction but not renal failure. Tranexamic acid significantly decreased blood transfusions, but was not statistically associated with other outcomes. Aminocaproic acid was not statistically associated with any measured outcome. Although aprotinin costs more than its alternatives, its costs may approximate those of its alternatives when longer time horizons are considered.

SUMMARY

We support the targeted use of aprotinin in adult cardiac surgery patients at high risk for bleeding or stroke, and discourage the use of aprotinin in those at high risk for renal failure. Although fewer data are available for tranexamic and aminocaproic acid, we support their use as alternatives to aprotinin in those at high risk for bleeding.

Perioperative antiplatelet therapy: the case for continuing therapy in patients at risk of myocardial infarction

Recent clinical data show that the risk of coronary thrombosis after antiplatelet drugs withdrawal is much higher than that of surgical bleeding if they are continued. In secondary prevention, aspirin is a lifelong therapy and should never be stopped. Clopidogrel is regarded as mandatory until the coronary stents are fully endothelialized, which takes 3 months for bare metal stents, but up to 1 yr for drug-eluting stents. Therefore, interruption of antiplatelet therapy 10 days before surgery should be revised. After reviewing the data on the use of antiplatelet drugs in cardiology and in surgery, we propose an algorithm for the management of patients, based on the risk of myocardial ischaemia and death compared with that of bleeding, for different types of surgery. Even if large prospective studies with a high degree of evidence are still lacking on different antiplatelet regimens during non-cardiac surgery, we propose that, apart from low coronary risk situations, patients on antiplatelet drugs should continue their treatment throughout surgery, except when bleeding might occur in a closed space. A therapeutic bridge with shorter-acting antiplatelet drugs may be considered.

Meta-analysis comparing the effectiveness and adverse outcomes of antifibrinolytic agents in cardiac surgery

BACKGROUND

Since the 1980s, antifibrinolytic therapies have assisted surgical teams in reducing the amount of blood loss. To date, however, serious questions remain regarding the safety and effectiveness of these agents.

METHODS AND RESULTS

We conducted a meta-analysis to compare aprotinin, epsilon-aminocaproic acid, and tranexamic acid with placebo and head to head on 8 clinical outcomes from 138 trials. Published randomized controlled trial data were collected from OVID/PubMed. Outcomes included total blood loss, transfusion of packed red blood cells, reexploration, mortality, stroke, myocardial infarction, dialysis-dependent renal failure, and renal dysfunction (0.5-mg/dL increase in creatinine from baseline). All agents were effective in significantly reducing blood loss by 226 to 348 mL and the proportion of patients transfused with packed red blood cells over placebo. Only high-dose aprotinin reduced the rate of reexploration (relative risk, 0.49; 95% CI, 0.33 to 0.73). There were no significant risks or benefits for any agent for mortality, stroke, myocardial infarction, or renal failure. However, high-dose aprotinin significantly increased the risk of renal dysfunction (relative risk, 1.47; 95% CI, 1.12 to 1.94), 12.9% versus 8.4%. Compared head to head, high-dose aprotinin demonstrated significant reduction in total blood loss over epsilon-aminocaproic acid (-184 mL; 95% CI, -256 to -112) and tranexamic acid (-195 mL; 95% CI, -286 to -105). There were no significant differences among any agent when compared head to head on other outcomes.

CONCLUSIONS

All antifibrinolytic agents were effective in reducing blood loss and transfusion. There were no significant risks or benefits for mortality, stroke, myocardial infarction, or renal failure. However, high-dose aprotinin was associated with a statistically significant increased risk of renal dysfunction.

The Role of Endogenous Kallikrein Inhibition in Perioperative Transfusion and Adverse Outcome in Cardiac Surgical Patients

OBJECTIVE

The goal of this study was to explore the relationship among endogenous plasma kallikrein inhibition (KI), perioperative bleeding, and adverse outcomes in cardiac surgery.

DESIGN

A prospective, observational study.

SETTING

University teaching hospitals.

PARTICIPANTS

Cardiac surgical patients.

INTERVENTIONS

Endogenous plasma KI levels (%) and kallikrein-like activity (KKA) were measured preoperatively, 30 minutes into cardiopulmonary bypass, and at the end of surgery. Patients were divided into quartiles of preoperative KI. Data including risk factors, blood loss, transfusion requirements, and postoperative outcomes were collected.

MEASUREMENTS AND MAIN RESULTS

Preoperative endogenous KI ranged from 40% to 175%, where 100% represents the activity of pooled healthy volunteer plasma. The quartiles of KI levels were as follows: quartile 1, KI = 40% to 83.8% (n = 40); quartile 2, KI = 84% to 101.5% (n = 40); quartile 3, KI = 102% to 120% (n = 42); and quartile 4, KI = 121% to 175% (n = 38). The hematocrits on admission to the intensive care unit were as follows: quartile 1, 28% +/- 4%; quartile 2, 26% +/- 4%; quartile 3, 26% +/- 4%; and quartile 4, 24% +/- 4% (p = 0.009). Blood product use was similar among quartiles in the operating room. Quartiles 3 and 4 received more blood (p = 0.003) and platelet (p = 0.04) transfusions than quartiles 1 and 2 in the first 24 hours after surgery. More patients in quartile 4 were ventilated for more than 24 hours after surgery (p < 0.05). Hospital length of stay was longest in quartile 4 (p = 0.002).

CONCLUSION

Contrary to expectation, higher endogenous KI levels were associated with more blood product transfusion, longer postoperative mechanical ventilation, and hospital length of stay. These findings raise questions as to the role of KI in postoperative outcomes.

Blood conservation strategies in cardiac surgery

Despite the continuous efforts to increase the safety of blood components, red blood cell transfusions remain associated with some risks and side effects. Therefore, numerous techniques have been developed to decrease blood use, but they also carry risks and bear costs. Most of them are frequently used in cardiac surgery, which still consumes a large part of the available blood supply. Among western countries the use of alternative techniques, but also transfusion practice, has been shown to vary markedly. 'Blood conservation' is a global concept engulfing all possible strategies aimed at reducing patients' exposure to allogeneic blood components. The development of the 'best strategy' consists of the selection of those techniques that are most appropriate to the local specific situation. It implies the establishment of a reliable system, collecting data both at the surgical team and at the medical level.

Non ST segment elevation acute coronary syndromes: A simplified risk-orientated algorithm

Non-ST segment elevation acute coronary syndromes (NSTE ACS) include a clinical spectrum that ranges from unstable angina to NSTE myocardial infarction. Management goals aim to prevent recurrent ACS and improve long-term outcomes by choosing a treatment strategy according to an estimate of the risk of an adverse outcome. Recent registry data suggest that patients with NSTE ACS frequently do not receive recommended treatment, and that risk stratification is not used to determine either the choice of treatment or the speed of access to coronary angiography. The present article evaluates the evidence for recommended treatment using information from recent trials and guidelines published by the major cardiac organizations in Europe and North America. Using this information, a multidisciplinary group developed a simplified algorithm that uses risk stratification to select an optimal early management strategy. Long-term outcomes are improved by a multi-faceted vascular protection strategy that is initiated at the time of hospitalization for NSTE ACS.