Implications of preoperative administration of aspirin in patients undergoing coronary artery bypass grafting. Department of Veterans Affairs Cooperative Study on Antiplatelet Therapy

Lack of Complications in Minor Skin Lesion Excisions in Patients Taking Aspirin or Warfarin Products

Many patients undergoing surgical procedures take medications that influence the coagulation system. It is common practice to discontinue the use of aspirin and warfarin products 7 to 10 days before any major surgical procedure. However, there is some controversy as to whether these medications should be discontinued for minor dermatological procedures. Our aim was to study the incidence of complications in patients receiving aspirin or warfarin and undergoing minor dermatological procedures. Two thousand three hundred twenty-six patients, operated on by a single surgeon, were studied for complications. Warfarin was used by 28 patients, 228 took aspirin, and the remainder took neither. There was no difference in the complication rate among the three groups as long as the surgeon diligently obtained hemostasis. It appears that patients taking aspirin or warfarin do not need to discontinue these medications before minor dermatological procedures.

Guideline on antiplatelet and anticoagulation management in cardiac surgery

This document presents a professional view of evidence-based recommendations around the issues of antiplatelet and anticoagulation management in cardiac surgery. It was prepared by the Audit and Guidelines Committee of the European Association for Cardio-Thoracic Surgery (EACTS). We review the following topics: evidence for aspirin, clopidogrel and warfarin cessation prior to cardiac surgery; perioperative interventions to reduce bleeding including the use of aprotinin and tranexamic acid; the use of thromboelastography to guide blood product usage; protamine reversal of heparin; the use of factor VIIa to control severe bleeding; anticoagulation after mechanical, tissue valve replacement and mitral valve repair; the use of antiplatelets and clopidogrel after cardiac surgery to improve graft patency and reduce thromboembolic complications and thromboprophylaxis in the postoperative period. This guideline is subject to continuous informal review, and when new evidence becomes available. The formal review date will be at 5 years from publication (September 2013).

Perioperative management of medications for psoriasis and psoriatic arthritis: a review for the dermasurgeon

BACKGROUND

Psoriasis affects an estimated 3% of the world's population. Many are on chronic immunosuppressive therapy for the cutaneous and joint manifestations of this disorder. The management of these medications in the perioperative period is controversial. Psoriasis and psoriatic arthritis medications can affect wound healing, hemostasis, and infection risk during cutaneous surgery.

OBJECTIVES

The objective of this article is to provide a critical review of various medications used for care of the psoriatic patient and their potential effect on cutaneous surgical procedures.

CONCLUSIONS

This review summarizes current understanding of wound healing, hemostatic effects, and infectious risks regarding many psoriasis medications including nonsteroidal anti-inflammatory drugs, cyclooxygenase inhibitors, corticosteroids, various immunosuppressants, and biologic response modifiers. Recommendations vary depending on the agent in question, type of procedure, and comorbid conditions in the patient. Caution is advised when using many of the medications reviewed due to lack of human data of their effects in the perioperative period.

Perioperative use of cardiac medical therapy among patients undergoing coronary artery bypass graft surgery: a systematic review

BACKGROUND

The use of perioperative cardiac medical therapy among patients undergoing coronary artery bypass graft surgery (CABG) has not been closely examined.

OBJECTIVES

The objective of this study was to systematically review the medical literature examining the effects of perioperative cardiac medical therapy on clinical outcomes among patients undergoing CABG.

METHODS

Using the Medline database and online clinical trial databases, we reviewed all randomized controlled trials (RCTs) and observational studies examining the effect of perioperative angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, antilipid agents (including statins), aspirin, beta-blockers, and calcium-channel blockers on clinical outcomes.

RESULTS

Our review identified 27 studies (6 RCTs, 21 observational studies), involving >700,000 patients, that examined the impact of perioperative medical therapy on clinical outcomes after CABG. Although studies provide conflicting results, the literature suggests that perioperative aspirin use may decrease inhospital mortality and myocardial infarction, whereas perioperative angiotensin-converting enzyme inhibitor use does not appear to be beneficial. Perioperative statin use reduces all-cause mortality at 30 days and cardiac death at 60 days and 1 year post-CABG but does not appear to reduce myocardial infarction or congestive heart failure rates. Multiple studies have demonstrated that pre- and postoperative beta-blockers are associated with a decrease in atrial fibrillation. In addition, beta-blockers may reduce inhospital and 30-day mortality, although these results are not consistent across all studies. Calcium-channel blockers do not appear to improve inhospital or 30-day mortality. No studies examined the perioperative use of angiotensin II receptor blockers or nonstatin antilipid agents among CABG patients.

CONCLUSIONS

The perioperative use of cardiac medical therapy among CABG patients remains understudied. Given their proven benefits among patients with cardiovascular disease and their potential to improve outcomes among CABG patients, further studies, particularly large RCTs, are needed.

Perioperative blood transfusion and blood conservation in cardiac surgery: the Society of Thoracic Surgeons and The Society of Cardiovascular Anesthesiologists clinical practice guideline

BACKGROUND

A minority of patients having cardiac procedures (15% to 20%) consume more than 80% of the blood products transfused at operation. Blood must be viewed as a scarce resource that carries risks and benefits. A careful review of available evidence can provide guidelines to allocate this valuable resource and improve patient outcomes.

METHODS

We reviewed all available published evidence related to blood conservation during cardiac operations, including randomized controlled trials, published observational information, and case reports. Conventional methods identified the level of evidence available for each of the blood conservation interventions. After considering the level of evidence, recommendations were made regarding each intervention using the American Heart Association/American College of Cardiology classification scheme.

RESULTS

Review of published reports identified a high-risk profile associated with increased postoperative blood transfusion. Six variables stand out as important indicators of risk: (1) advanced age, (2) low preoperative red blood cell volume (preoperative anemia or small body size), (3) preoperative antiplatelet or antithrombotic drugs, (4) reoperative or complex procedures, (5) emergency operations, and (6) noncardiac patient comorbidities. Careful review revealed preoperative and perioperative interventions that are likely to reduce bleeding and postoperative blood transfusion. Preoperative interventions that are likely to reduce blood transfusion include identification of high-risk patients who should receive all available preoperative and perioperative blood conservation interventions and limitation of antithrombotic drugs. Perioperative blood conservation interventions include use of antifibrinolytic drugs, selective use of off-pump coronary artery bypass graft surgery, routine use of a cell-saving device, and implementation of appropriate transfusion indications. An important intervention is application of a multimodality blood conservation program that is institution based, accepted by all health care providers, and that involves well thought out transfusion algorithms to guide transfusion decisions.

CONCLUSIONS

Based on available evidence, institution-specific protocols should screen for high-risk patients, as blood conservation interventions are likely to be most productive for this high-risk subset. Available evidence-based blood conservation techniques include (1) drugs that increase preoperative blood volume (eg, erythropoietin) or decrease postoperative bleeding (eg, antifibrinolytics), (2) devices that conserve blood (eg, intraoperative blood salvage and blood sparing interventions), (3) interventions that protect the patient's own blood from the stress of operation (eg, autologous predonation and normovolemic hemodilution), (4) consensus, institution-specific blood transfusion algorithms supplemented with point-of-care testing, and most importantly, (5) a multimodality approach to blood conservation combining all of the above.

Does the Use of Preoperative Aspirin Increase the Risk of Bleeding in Patients Undergoing Coronary Artery Bypass Grafting Surgery? Systematic Review and Meta-Analysis

BACKGROUND

The traditional recommendation has been to stop Aspirin seven to 10 days prior to coronary artery bypass surgery to reduce the potential risk of bleeding. A few reports have shown that Aspirin did not increase the risk of bleeding and may be beneficial to be continued until the time of surgery. The objective of this review was to evaluate the effect of preoperative Aspirin on bleeding in patients undergoing elective bypass surgery.

METHODS

A meta-analysis of 10 randomized and nonrandomized studies reporting comparisons between Aspirin and control was undertaken. The primary outcome was the total amount of postoperative chest tube drainage. Secondary outcomes were the number of units of packed red blood cell transfusion, platelet transfusion, fresh frozen plasma transfusion, and number of patients reexplored for bleeding.

RESULTS

Ten studies, involving 1748 patients, met the inclusion criteria for this review of whom 913 were in the Aspirin group and 835 were in the control group. Pooling the results of all studies showed a significant increase in blood loss and transfusion of red blood cells and fresh frozen plasma in the Aspirin group (p < 0.05). There was no significant difference between the two groups in the rate of platelet transfusion, or the incidence of reexploration (p > 0.05). Included studies were heterogeneous and of low methodological quality.

CONCLUSION

Aspirin is associated with increased chest tube drainage and may be associated with a greater requirement for blood products. High-quality prospective studies are warranted to reassess the effect of Aspirin on important postoperative outcomes.

Antiplatelet therapy preceding coronary artery surgery

BACKGROUND AND OBJECTIVE

Bleeding after cardiac surgery correlates with morbidity and mortality. The aim of this study was to determine the influence of antiplatelet therapy on bleeding and transfusion rates in coronary artery bypass grafting.

METHODS

Forty patients receiving aspirin and/or clopidogrel/ticlopidine within 7 days prior to surgery were retrospectively compared to 40 control patients lacking antiplatelet therapy for at least 8 preoperative days. Blood loss was assessed as chest-tube drainage during the first 12 h after surgery. Units transfused were recorded intraoperatively and during stay in the intensive care unit.

RESULTS

Both groups were comparable for pre- and intraoperative data. Irrespective of single or combined antiplatelet therapy, treated patients demonstrated lower fractions of the creatine-kinase isoenzyme MB (5.8 +/- 3.1 vs. 8.2 +/- 4.1%; P = 0.004) and infarction rates (0 vs. 3; P = 0.240) than control patients, but had significantly more haemorrhages (940 +/- 861 mL vs. 412 +/- 590 mL; P = 0.002) and transfusion requirements (red cells: 4.5 +/- 4.9 vs. 1.5 +/- 2.3, plasma: 4.9 +/- 6.4 vs. 1.3 +/- 2.5, platelets: 1.5 +/- 1.3 vs. 0.1 +/- 0.2; all P < or = 0.001). The differences to control patients were more pronounced for only short antiplatelet therapy free intervals or ongoing antiplatelet therapy (P < or = 2 days < or = 0.019). For antiplatelet therapy free intervals longer than 2 days, bleeding and transfusion rates (except for platelets) were nonsignificantly higher as compared to control patients (P > or = 0.058).

CONCLUSIONS

To overcome increased blood loss and transfusion rates, antiplatelet therapy should be discontinued for at least 2 days before elective coronary surgery. Whether patients at high risk for myocardial infarction might benefit from ongoing antiplatelet therapy remains to be investigated.

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

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

Patients with rheumatoid arthritis undergoing surgery: how should we deal with antirheumatic treatment?

OBJECTIVES

To review published data on the perioperative management of antirheumatic treatment and perioperative outcome in patients with rheumatoid arthritis (RA).

METHODS

The review is based on a MEDLINE (PubMed) search of the English-language literature from 1965 to 2005, using the index keywords "rheumatoid arthritis" and "surgery". As co-indexing terms the different disease-modifying antirheumatic drugs (DMARDs) as well as nonsteroidal anti-inflammatory drugs (NSAIDs) and "glucocorticoids" were used. In addition, citations from retrieved articles were scanned for additional references. Furthermore, because the number of published articles is so limited, relevant abstracts presented at congresses were included in the analysis.

RESULTS

Continuation of methotrexate (MTX) appears to be safe in the perioperative period. Only a limited number of studies address the use of leflunomide and the results are conflicting. Because of the very long drug half-life, its discontinuation would need to be of long duration and is probably not necessary. Data on hydroxychloroquine do not show increased risks of infection. Regarding sulfasalazine, there are no studies from which definite answers could be drawn on whether it should be withheld perioperatively. Preliminary data show that the risk of infections during treatment with TNF-blocking agents may be lower than initially expected. The only available recommendation (Club Rhumatismes et Inflammation, CRI) suggests discontinuing the drugs before surgery for several weeks, depending on the risk of infection and the drug used. They should not be restarted until wound healing is complete. To avoid the antiplatelet effect during surgery, NSAIDs other than aspirin should be withheld for a duration of 4 to 5 times the drug half-life. Patients with chronic glucocorticoid therapy and suppressed hypothalamic-pituitary-adrenal (HPA) axis need perioperative supplementation.

CONCLUSIONS

While continuation of MTX likely is safe, data on other DMARDs are sparse. In particular, more data on the perioperative use of the biologic agents are needed.

Impact of platelet testing on presurgical screening and implications for cardiac and noncardiac surgical procedures

Bleeding is a common complication of cardiac surgery, accounting for a significant portion of the total transfusions performed in the United States. This may be due in part to surgical factors and to the fibrinolysis and platelet activation induced by cardiopulmonary bypass. The increasing frequency with which antiplatelet medications are used to prevent thrombosis in cardiac surgical patients with cardiovascular disease also elevates the risk for postoperative bleeding. The resulting coagulopathy and need for transfusions may increase morbidity and mortality risk in cardiac surgical patients, depending on the specific antiplatelet agent used, as well as on patient factors. Empiric platelet transfusion, the frequency of which varies greatly among institutions, does not reliably prevent these complications and may even increase the risk for adverse outcomes. Platelet function testing, particularly with newer testing systems, may be a valuable tool for making decisions about stopping antiplatelet drug administration, surgical timing with respect to bleeding risk, and platelet transfusion in cardiac surgical patients.

Discontinuation of perioperative antiplatelet and anticoagulant therapy in stroke patients

Growing evidence suggests that perioperative withdrawal of ASA for secondary stroke prevention increases thromboembolic risk without the associated benefit of decreased bleeding complications. ASA maintenance is acceptable in many procedures, including invasive ones. Many procedures, in particular ophthalmologic, dermatologic, and dental surgeries, also are safe while continuing oral AC. Warfarin has been continued successfully even in some surgeries that have high bleeding risk. When the risk is too high, temporary bridging therapy with LWMH is safe in many populations. Although the exact thromboembolic risks associated with temporary cessation of AP and AC are unknown and likely low, morbidity and mortality associated with thromboembolism are high. Further studies investigating the risks and benefits of maintaining AP and AC during procedures, particularly invasive ones, are needed. Meanwhile, it is critical that physicians understand the risks and benefits of perioperative AP and AC and the variety of procedures in which these agents can be safely continued.

Low-dose aspirin before intracranial surgery--results of a survey among neurosurgeons in Germany

BACKGROUND

Increasing numbers of patients presenting for intracranial surgery are receiving concurrent medication with low-dose aspirin, leading to dysfunctional circulating platelets, which might increase the peri-operative risk of bleeding.

OBJECTIVE

To survey the opinions and working practices of neurosurgical facilities in Germany regarding patients who present with low-dose aspirin medication before elective intracranial surgery. Methods. Questionnaires were sent to 210 neurosurgical facilities asking five main questions: (1) the adherence of any policy of stopping aspirin pre-operatively, (2) the personal risk assessment for patients with brain surgery under low-dose aspirin medication, (3) the preferred method of treatment for excessive bleeding in this context, (4) personal knowledge of haemorrhagic complications in this group of patients, and (5) the characteristics of the neurosurgical units concerned.

RESULTS

There were 138 (65.7%) valid responses. Of the respondents, 111 (80.4%) had a departmental policy for the discontinuation of pre-operative aspirin treatment. The mean time for discontinuation of aspirin pre-operatively was 7.3 days (range: 0-21 days). 107 respondents (77.5%) considered that patients taking low-dose aspirin were at increased risk for excessive peri-operative haemorrhage, and 80 (58%) reported having personal experience of such problems. Ninety-seven respondents (70.3%) would use special medical therapy, preferably desmopressin, if haemorrhagic complications developed intra-operatively. The mean amount of intracranial operations per year in each neurosurgical facility was 494 (range: 50-1700).

CONCLUSIONS

The majority of neurosurgical facilities in Germany have distinct departmental policies concerning the discontinuation of low-dose aspirin pre-operatively, with an average of 7.3 days. Three-quarter of the respondents felt that aspirin was a risk factor for haemorrhagic complications associated with intracranial procedures, and more than half of the interviewees reported having personal experience of such problems. Various medicamentous methods of counteracting aspirin-induced platelet dysfunction and excessive bleeding in this context are discussed and evaluated.

Low-dose aspirin before spinal surgery: results of a survey among neurosurgeons in Germany

The main problem faced by the increasing numbers of patients presenting for spinal surgery are receiving concurrent medication with low-dose aspirin, leading to dysfunctional circulating platelets. The contribution of low-dose aspirin to increased peri-operative risk of bleeding and blood loss is a contentious issue with conflicting published results from different surgical groups. Data from neurosurgical spine patients is sparse, but aspirin has been identified as an important risk factor in the development of post-operative hematoma following intracranial surgery. We surveyed the opinions and working practices of the neurosurgical facilities performing spinal operations in Germany regarding patients who present for elective spinal surgery. Identical questionnaires were sent to 210 neurosurgical facilities and proffered five main questions: (1) the adherence of any policy of stopping aspirin pre-operatively, (2) the personal risk assessment for patients with spinal surgery under low-dose aspirin medication, (3) the preferred method of treatment for excessive bleeding in this context, (4) personal knowledge of hemorrhagic complications in this group of patients, and (5) the characteristics of the neurosurgical units concerned. There were 145 (69.1%) responses of which 142 (67.6%) were valid. Of the respondents, 114 (80.3%) had a (written) departmental policy for the discontinuation of pre-operative aspirin treatment, 28 (19.7%) were unaware of such a policy. The mean time suggested for discontinuation of aspirin pre-operatively was 6.9 days (range: 0-21 days), with seven respondents who perform the operations despite the ongoing aspirin medication. Ninety-four respondents (66.2%) considered that patients taking low-dose aspirin were at increased risk for excessive peri-operative hemorrhage or were indetermined (8.6%), and 73 (51.4%) reported having personal experience of such problems. Ninety-two respondents (65.5%) would use special medical therapy, preferably Desmopressin alone or in combination with other blood products or prohemostatic agents (46.1%), if hemorrhagic complications developed intra- or post-operatively. The average number of spinal operations per year in each service was 607.9 (range: 40-1,500). Despite the existence of distinct departmental policies concerning the discontinuation of low-dose aspirin pre-operatively in the majority of neurosurgical facilities performing spinal operations, there is a wide range of the moment of this interruption with an average of 7 days. Two-thirds of the respondents felt that aspirin was a risk factor for hemorrhagic complications associated with spinal procedures, and more than half of the interviewees reported having personal experience of such problems. Finally, various medicamentous methods of counteracting aspirin-induced platelet dysfunction and excessive bleeding in this context are elicited, discussed and evaluated.

Balancing the benefit and risk of oral antiplatelet agents in coronary artery bypass surgery

Concern about possible hemorrhagic complications arising from use of oral antiplatelet agents in immediate proximity to coronary artery bypass graft (CABG) surgery leads many clinicians to avoid or discontinue these agents preoperatively. Recent evidence suggests that aspirin and clopidogrel can be used with relative safety in the preoperative period; dual antiplatelet therapy in the 5 days immediately preceding CABG surgery results in a moderate and variable increase in the risk of procedural bleeding. This modest hemorrhagic risk may be acceptable, given the clinical benefits of sustained antiplatelet therapy in preventing graft occlusion and ischemic complications pre- and post-CABG. Because the bleeding risk with aspirin is dose dependent, use of a low dose is preferred post-CABG.

Antithrombotic therapy in cardiac surgery

PURPOSE

To review the perioperative management of antithrombotic therapy in cardiac surgery, including the management of cardiopulmonary bypass (CPB) and off-pump surgery.

METHODS

A review of the relevant English literature over the period 1975-2005 was undertaken, in addition to a review of international practices in antithrombotic therapy in cardiac surgery.

PRINCIPAL FINDINGS

Cardiopulmonary bypass is required in most procedures and makes anticoagulation mandatory. Anticoagulation is, usually, achieved with unfractionnated heparin (UFH). Unfractionated heparin is monitored by point-of-care (POC) testing, such as the activated clotting time or the determination of heparin concentration. The target values of both tests remain empirical, with no clearly validated thresholds. The target value needs to be adjusted according to the POC test, given significant variations between devices and activators. After CABG, the need for antiplatelet therapy is well demonstrated, in order to limit the risk of postoperative death or ischemic events, and improve venous graft patency. Immediately after valvular surgery, antithrombotic therapy should take into account the specific risk carried by each patient and by each prosthetic device. The risk of venous thromboembolism, though poorly defined, is also present in the postoperative period and may require additional attention. Given the frequent exposure to UFH, occurrence of heparin-induced thrombocytopenia is not infrequent in these patients and requires careful individual management.

CONCLUSIONS

Antithrombotic therapy is an essential component of cardiac surgery. Yet, with the exception of antiplatelet agents in CABG patients, antithrombotic therapy is often based on the clinical experience of medical teams more than on an evidence-based assessment of the literature.

Cardioprotective Strategies to Improve Long-Term Outcomes Following Coronary Artery Bypass Surgery

BACKGROUND AND AIM

Cardioprotective strategies implemented to prevent ischemic events in patients at risk for cardiovascular disease have decreased morbidity and prolonged survival. In this review, we have used evidence-based medicine and number-needed-to-treat (NNT) analyses to determine which interventions are most beneficial in minimizing ischemic events and prolonging survival following coronary artery bypass graft (CABG) surgery.

METHODS

Therapeutic interventions available to minimize ischemic events in the post-CABG patient were analyzed using ACC/AHA Classifications and Level of Evidence Criteria. Based on these recommendations, NNT analyses were performed to determine the effectiveness of each intervention compared to the number of patients needed to be treated before a benefit was apparent.

RESULTS

The most beneficial intervention to improve mortality following CABG was the use of high tissue angiotensin-converting enzyme inhibitors, followed by statins and smoking cessation.

CONCLUSIONS

NNT analyses and evidence-based medicine recommendations provide surgeons with cardioprotective strategies to improve long-term outcomes following CABG surgery.

Heparins, low-molecular-weight heparins, and pentasaccharides

Elderly patients require special consideration when administered anticoagulants because of age-related alterations in renal function, protein binding, and increased bleeding risk. Unfractionated heparin can be used in most patients but difficulties with dosing and monitoring often lead to inadequate anticoagulation. Low-molecular-weight heparin has more predictable pharmacokinetics than conventional heparin, but requires dose adjustments in renal impairment and obesity. Fondaparinux is a synthetic pentasaccharide that is being used increasingly for both treatment and prophylaxis of venous thromboembolism. The immune-mediated form of heparin-induced thrombocytopenia is a syndrome with thrombocytopenia or thrombosis in the setting of heparin use. Heparin-induced thrombocytopenia must be identified early, and treated with argatroban or lepirudin to avoid life-threatening complications.

Anticoagulation: American College of Chest Physicians guidelines for the prevention and management of postoperative atrial fibrillation after cardiac surgery

Post-cardiac surgery atrial fibrillation (AF) places patients at risk for thromboembolism and stroke, while the surgery and cardiopulmonary bypass alter the multiple factors of coagulation and may increase the tendency to bleed. It is in the context of this complex clinical picture that the physician must make decisions regarding the risks and benefits of anticoagulation therapy to lower the risk for thromboembolism and stroke associated with postoperative AF. Physicians must also weigh the usually transient and self-limited duration of new-onset postoperative AF against the potential for postoperative bleeding if anticoagulation therapy is started. No randomized, controlled clinical trials are available that specifically address the problem of anticoagulation therapy for the postoperative AF. In that context, recommendations are based on the established therapy for nonsurgical situations modified by the potential risk of bleeding in the postoperative patient.

Preoperative Aspirin Therapy Is Associated With Improved Postoperative Outcomes in Patients Undergoing Coronary Artery Bypass Grafting

Background— Aspirin is beneficial in the setting of atherosclerotic cardiovascular disease. There are limited data evaluating preoperative aspirin administration preceding coronary artery bypass grafting and associated postoperative outcomes.

Methods and Results— Using prospectively collected data from 1636 consecutive patients undergoing first-time isolated coronary artery bypass surgery at our institution from January 2000 through December 2002, we evaluated the association between aspirin usage within the 5 days preceding coronary bypass surgery and risk of adverse in-hospital postoperative events. A logistic regression model, which included propensity scores, was used to adjust for remaining differences between groups. Overall, there were 36 deaths (2.2%) and 48 adverse cerebrovascular events (2.9%) in the postoperative hospitalization period. Patients receiving preoperative aspirin (n=1316) had significantly lower postoperative in-hospital mortality compared with those not receiving preoperative aspirin [1.7% versus 4.4%; adjusted odds ratio (OR), 0.34; 95% CI, 0.15 to 0.75; P =0.007]. Rates of postoperative cerebrovascular events were similar between groups (2.7% versus 3.8%; adjusted OR, 0.67; 95% CI, 0.32 to 1.50; P =0.31). Preoperative aspirin therapy was not associated with an increased risk of reoperation for bleeding (3.5% versus 3.4%; P =0.96) or requirement for postoperative blood product transfusion (adjusted OR, 1.17; 95% CI, 0.88 to 1.54; P =0.28).

Conclusions— Aspirin usage within the 5 days preceding coronary artery bypass surgery is associated with a lower risk of postoperative in-hospital mortality and appears to be safe without an associated increased risk of reoperation for bleeding or need for blood product transfusion.

A comparison of Plateletworks and platelet aggregometry for the assessment of aspirin-related platelet dysfunction in cardiac surgical patients

OBJECTIVE

To compare the assessment of aspirin-related platelet dysfunction using Plateletworks (Helena Laboratories, Beaumont, TX), a new point-of-care platelet function analyzer, with turbidometric platelet aggregometry, in cardiac surgical patients.

DESIGN

Prospective observational study.

SETTING

University-affiliated teaching hospital.

PARTICIPANTS

Fifty consecutive adult patients undergoing elective cardiac surgery for coronary artery bypass grafting or cardiac valve replacement.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Platelet function was assessed by Plateletworks and turbidometric platelet aggregometry before the commencement of anesthesia. Collagen, 10 microg/mL, was used as the agonist for both techniques. The area under the receiver-operator curve for the identification of recent aspirin ingestion (<or=48 hours v >or=72 hours) using Plateletworks was 0.58 (95% confidence interval [CI] 0.42-0.75) versus 0.77 (95% CI 0.61-0.95) for turbidometric platelet aggregometry. The Spearman correlation coefficient (rho) between preoperative Plateletworks trade mark and postoperative mediastinal blood loss was 0.07 (p = 0.58), and between preoperative turbidometric platelet aggregometry and postoperative mediastinal blood loss was -0.31 (p = 0.03). On completion of surgery, the correlation coefficients were 0.14 (p = 0.34) and -0.29 (p = 0.08), respectively.

CONCLUSION

These findings suggest that Plateletworks is of limited use for the detection of aspirin-related platelet defects in cardiac surgical patients.

Hemorrhagic Complications of Anticoagulant Treatment

This chapter about hemorrhagic complications of anticoagulant treatment is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Bleeding is the major complication of anticoagulant therapy. The criteria for defining the severity of bleeding varies considerably between studies, accounting in part for the variation in the rates of bleeding reported. The major determinants of vitamin K antagonist-induced bleeding are the intensity of the anticoagulant effect, underlying patient characteristics, and the length of therapy. There is good evidence that vitamin K antagonist therapy, targeted international normalized ratio (INR) of 2.5 (range, 2.0 to 3.0), is associated with a lower risk of bleeding than therapy targeted at an INR > 3.0. The risk of bleeding associated with IV unfractionated heparin (UFH) in patients with acute venous thromboembolism (VTE) is < 3% in recent trials. This bleeding risk may increase with increasing heparin dosages and age (> 70 years). Low molecular weight heparin (LMWH) is associated with less major bleeding compared with UFH in acute VTE. UFH and LMWH are not associated with an increase in major bleeding in ischemic coronary syndromes, but are associated with an increase in major bleeding in ischemic stroke. Information on bleeding associated with the newer generation of antithrombotic agents has begun to emerge. In terms of treatment decision making for anticoagulant therapy, bleeding risk cannot be considered alone, ie, the potential decrease in thromboembolism must be balanced against the potential increased bleeding risk.

Antithrombotic Therapy in Peripheral Arterial Occlusive Disease

This chapter about antithrombotic therapy for peripheral arterial occlusive disease is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs, and Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004;126:179S-187S). Among the key recommendations in this chapter are the following: For patients with chronic limb ischemia, we recommend lifelong aspirin therapy in comparison to no antiplatelet therapy in patients with clinically manifest coronary or cerebrovascular disease (Grade 1A) and in those without clinically manifest coronary or cerebrovascular disease (Grade 1C+). We recommend clopidogrel over no antiplatelet therapy (Grade 1C+) but suggest that aspirin be used instead of clopidogrel (Grade 2A). For patients with disabling intermittent claudication who do not respond to conservative measures and who are not candidates for surgical or catheter-based intervention, we suggest cilostazol (Grade 2A). We suggest that clinicians not use cilostazol in patients with less-disabling claudication (Grade 2A). In these patients, we recommend against the use of pentoxifylline (Grade 1B). We suggest clinicians not use prostaglandins (Grade 2B). In patients with intermittent claudication, we recommend against the use of anticoagulants (Grade 1A). In patients with acute arterial emboli or thrombosis, we recommend treatment with immediate systemic anticoagulation with unfractionated heparin (UFH) [Grade 1C]. We also recommend systemic anticoagulation with UFH followed by long-term vitamin K antagonist (VKA) in patients with embolism [Grade 1C]). For patients undergoing major vascular reconstructive procedures, we recommend UFH at the time of application of vascular cross-clamps (Grade 1A). In patients undergoing prosthetic infrainguinal bypass, we recommend aspirin (Grade 1A). In patients undergoing infrainguinal femoropopliteal or distal vein bypass, we suggest that clinicians do not routinely use a VKA (Grade 2A). For routine patients undergoing infrainguinal bypass without special risk factors for occlusion, we recommend against VKA plus aspirin (Grade 1A). For those at high risk of bypass occlusion and limb loss, we suggest VKA plus aspirin (Grade 2B). In patients undergoing carotid endarterectomy, we recommend aspirin preoperatively and continued indefinitely (Grade 1A). In nonoperative patients with asymptomatic or recurrent carotid stenosis, we recommend lifelong aspirin (Grade 1C+). For all patients undergoing extremity balloon angioplasty, we recommend long-term aspirin (Grade 1C+).

Reexploration for bleeding after coronary artery bypass surgery: risk factors, outcomes, and the effect of time delay

BACKGROUND

We aimed to identify risk factors for reexploration for bleeding after surgical revascularization in our practice. We also looked at the impact of resternotomy and the effect of time delay on mortality and other in-hospital outcomes.

METHODS

In all, 2,898 consecutive patients undergoing coronary artery bypass grafting between April 1999 and March 2002 were retrospectively analyzed from our cardiac surgery registry. Multivariate logistic regression analysis was used to identify risk factors for reexploration for bleeding. To assess the effect of preoperative aspirin and heparin, reexploration patients were propensity matched with unique patients not requiring reexploration. We carried out a casenote review to ascertain the timing and causes for bleeding in patients undergoing resternotomy.

RESULTS

Eighty-nine patients (3.1%) underwent reexploration for bleeding. Multivariate analysis revealed smaller body mass index (p = 0.003), nonelective surgery (p = 0.022), 5 or more distal anastomoses (p = 0.035), and increased age (p = 0.041) to have increased risks. Propensity-matched analysis showed that preoperative use of aspirin (p = 0.004) and heparin (p = 0.001) were associated with increased risk in the on-pump coronary surgery group only. Patients requiring resternotomy had a significantly greater need for inotropic agents (p < 0.001), and longer intensive care unit stay (p < 0.001) and postoperative stay (p < 0.001) than their propensity-matched controls. However, there was no significant difference in the mortality rate. Adverse outcomes were significantly higher when patients waited more than 12 hours after return to the intensive care unit for resternotomy.

CONCLUSIONS

Risk factors for reexploration for bleeding after coronary artery bypass grafting include older age, smaller body mass index, nonelective cases, and 5 or more distal anastomoses. Preoperative aspirin and heparin were risk factors for the on-pump coronary artery surgery group. Patients needing reexploration are at higher risk of complications if the time to reexploration is prolonged. Policies that promote early return to the operating theater for reexploration should be encouraged.

Guidelines on the management of secondary prophylaxis of vascular events in stable patients in primary care

Atherothrombosis, thrombus formation superimposed on an existing atherosclerotic plaque, is an acute process leading to ischaemic events such as myocardial infarction, stroke and critical limb ischaemia. Patients presenting with clinical conditions associated with atherothrombosis are at increased risk of subsequent vascular events. The beneficial effect of antiplatelet therapies for short-term and long-term secondary prevention of atherothrombotic events has been established. These guidelines aim to provide evidence-based recommendations that will assist in the antiplatelet-mediated secondary prophylaxis of vascular events in patients with stable cardiovascular disease treated in the primary healthcare setting. Medline and the Cochrane library were accessed using free-text strategies in the domains of antiplatelet agents and antithrombotics. Development of the guidelines was driven by a series of Steering Committee meetings, in which the quality of relevant studies was assessed and identified using narrative summary. These guidelines present evidence and recommendations for the treatment of numerous atherothrombotic indications depending on individual patient circumstances.

The effect of aspirin on blood loss and transfusion requirements in patients with femoral neck fractures

Although it is widely accepted that aspirin will increase the risk of intra- and post-operative bleeding, clinical studies have not consistently supported this assumption. We aimed to assess the effect of pre-operative aspirin on blood loss and transfusion requirements in patients undergoing emergency fixation of femoral neck fractures. A prospective case-control study was undertaken in patients presenting with femoral neck fractures. Parameters recorded included intra-operative blood loss, post-operative blood loss, transfusion requirements and peri-operative reduction in haemoglobin concentration. Of 89 patients presenting with femoral neck fractures 32 were on long-term aspirin therapy. Pre-operative aspirin ingestion did not significantly affect peri-operative blood loss, or change in haemoglobin concentration or haematocrit. However those patients taking aspirin pre-operatively had a significantly lower haemoglobin concentration and haematocrit and were more likely to be anaemic at presentation than those who were not receiving aspirin. Patients taking aspirin were also more likely to receive blood transfusion post-operatively.

Predictors of transfusion requirements for cardiac surgical procedures at a blood conservation center

BACKGROUND

Previous studies defining perioperative risk factors for allogeneic transfusion requirements in cardiac surgery were limited to highly selected cardiac surgery populations or were associated with high transfusion rates. The purpose of this study was to determine perioperative risk factors and create a formula to predict transfusion requirements for major cardiac surgical procedures in a center that practices a multimodality approach to blood conservation.

METHODS

We performed an observational study on 307 consecutive patients undergoing coronary artery bypass grafting, valve, and combined (coronary artery bypass grafting and valve) procedures. An equation was derived to estimate the risk of transfusion based on preoperative risk factors using multivariate analysis. In patients with a calculated probability of transfusion of at least 5%, intraoperative predictors of transfusion were identified by multivariate analysis.

RESULTS

Thirty-five patients (11%) required intraoperative or postoperative allogeneic transfusions. Preoperative factors as independent predictors for transfusions included red blood cell mass, type of operation, urgency of operation, number of diseased vessels, serum creatinine of at least 1.3 mg/dL, and preoperative prothrombin time. Intraoperative factors included cardiopulmonary bypass time, three or fewer bypass grafts, lesser volume of acute normovolemic hemodilution removed, and total crystalloid infusion of at least 2,500 mL. The derived formula was applied to a validation cohort of 246 patients, and the observed transfusion rates conformed well to the predicted risks.

CONCLUSIONS

A multimodality approach to blood conservation in cardiac surgery resulted in a low transfusion rate. Identifying patients' risks for transfusion should alter patient management perioperatively to decrease their transfusion rate and make more efficient use of blood resources.

Aspirin therapy and bleeding during proximal femoral fracture surgery

To assess the effect of daily low-dose aspirin therapy on perioperative bleeding of patients operated on for proximal femoral fracture, we did a prospective case-control study. During 14 months, we followed up 104 patients, 39 of whom were taking aspirin before the injury. The bleeding was estimated by the number of blood units needed perioperatively, the change in hemoglobin values, and followup on complications and drain volume. The aspirin-treated group received an average of 0.5 units of blood more than the control group, postoperatively. This finding was statistically significant. The groups did not differ significantly in any other bleeding parameter. No major bleeding occurred in the patients. It is safe to do surgery for a proximal femoral fracture in patients who are taking aspirin.

Patterns of secondary prevention in older patients undergoing coronary artery bypass grafting during hospitalization for acute myocardial infarction

BACKGROUND

Aggressive risk factor modification decreases cardiovascular events and mortality in patients after coronary artery bypass grafting (CABG). Little is known regarding the use of secondary prevention in older patients undergoing CABG during hospitalization for acute myocardial infarction (AMI).

METHODS AND RESULTS

Medical records were reviewed for a sample of 37,513 patients hospitalized with AMI in the United States between April 1998 and March 1999. Patients >or=65 years of age who underwent CABG after AMI (n=2,267 [8%]) were evaluated for the prescription of 4 therapies at discharge: aspirin, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and lipid lowering, in eligible patients without contraindications to therapy and compared with patients who did not undergo CABG (n=26,484 [92%]). Patients undergoing CABG had higher rates of aspirin than patients who did not undergo CABG (88.0% versus 83.2%, P=0.0002). However, CABG patients were less likely to receive beta-blockers (61.5% versus 72.1%, P<0.0001), ACE inhibitors (55.5% versus 72.1%, P<0.0001), or lipid lowering (34.7% versus 55.7%, P<0.0001) prescriptions than patients who did not undergo CABG. After adjustment for disease severity, patients undergoing CABG were no longer more likely to receive discharge aspirin, and the magnitude of other differences in care increased.

CONCLUSIONS

Evidence-based discharge therapies are underutilized in older patients who underwent CABG during hospitalization for AMI. Although national efforts focusing on improving short-term surgical mortality have been successful, strategies should be developed to increase the utilization of therapies known to improve long-term mortality in patients undergoing CABG.

Effect of preoperative aspirin use in off-pump coronary artery bypass operations

BACKGROUND

The effect of preoperative aspirin use until the day of operation on mortality rate and bleeding risks in patients who had on-pump coronary artery bypass operation has been well documented. However, the effect of aspirin use in patients undergoing off-pump coronary artery bypass operation (OPCAB) with regard to postoperative blood loss and morbidity has not been studied. We aimed to determine the effects of continuing aspirin therapy preoperatively.

METHODS

We performed a retrospective study of 340 patients who had first-time OPCAB between January 1998 and September 2001. A propensity score for receiving aspirin until the day of operation was constructed from core patient characteristics. All aspirin users (n = 170) were matched with unique 170 nonaspirin users by identical propensity score. The primary outcome measures were in-hospital mortality rate and hemorrhage-related outcomes (postoperative blood loss in the intensive care unit, reexploration for bleeding, and blood product requirements). Secondary outcome measures were stroke, myocardial infarction, gastrointestinal bleeding, and sternal wound infections.

RESULTS

There were no differences in patient characteristics between aspirin users and nonaspirin users. The average postoperative blood loss (845 mL versus 775 mL; p = 0.157) and the rate of reexploration for bleeding (3.5% versus 3.5%; p > 0.99) were similar in aspirin users and nonaspirin users. We found no significant difference between blood product requirements for the two groups. Similarly, we found no significant difference in the incidence of the secondary outcomes.

CONCLUSIONS

Preoperative aspirin did not increase bleeding-related complications, mortality rate, or other morbidities in patients who had off-pump coronary artery operation.

Factors affecting transfusion of fresh frozen plasma, platelets, and red blood cells during elective coronary artery bypass graft surgery

CONTEXT

The ability to predict the use of blood components during surgery will improve the blood bank's ability to provide efficient service.

OBJECTIVE

Develop prediction models using preoperative risk factors to assess blood component usage during elective coronary artery bypass graft surgery (CABG).

DESIGN

Eighty-three preoperative, multidimensional risk variables were evaluated for patients undergoing elective CABG-only surgery.

MAIN OUTCOMES MEASURES

The study endpoints included transfusion of fresh frozen plasma (FFP), platelets, and red blood cells (RBC). Multivariate logistic regression models were built to assess the predictors related to each of these endpoints.

SETTING

Department of Veterans Affairs (VA) health care system.

PATIENTS

Records for 3034 patients undergoing elective CABG-only procedures; 1033 patients received a blood component transfusion during CABG.

RESULTS

Previous heart surgery and decreased ejection fraction were significant predictors of transfusion for all blood components. Platelet count was predictive of platelet transfusion and FFP utilization. Baseline hemoglobin was a predictive factor for more than 2 units of RBC. Some significant hospital variation was noted beyond that predicted by patient risk factors alone.

CONCLUSIONS

Prediction models based on preoperative variables may facilitate blood component management for patients undergoing elective CABG. Algorithms are available to predict transfusion resources to assist blood banks in improving responsiveness to clinical needs. Predictors for use of each blood component may be identified prior to elective CABG for VA patients.

Outcome of aspirin use during excision of cutaneous lesions

The perioperative course of 253 patients undergoing excision of cutaneous and subcutaneous lesions by the same surgeon was evaluated, comparing patients using aspirin and those not using aspirin. Intraoperative methods of obtaining hemostasis and the incidence of postoperative complications were evaluated. Suture ligatures were used more frequently in the group using aspirin, but there was no statistical difference in the use of electrocautery. There was also no difference in the incidence of wound dehiscence, erythema, or hematoma. The outcome of excision of cutaneous and subcutaneous lesions under local anesthesia is not affected by patients using aspirin.

Aspirin does not increase bleeding complications after transbronchial biopsy

STUDY OBJECTIVES

The present study was performed to determine whether the risk of bleeding after transbronchial lung biopsy is increased in patients taking aspirin.

DESIGN

Prospective cohort study.

PATIENTS AND INTERVENTIONS

After excluding patients with other coagulation problems, 1,217 patients who had undergone transbronchial lung biopsy during a prospective 1.5-year study period were included in this study. The use of aspirin was not discontinued before the procedure. Two hundred eighty-five patients (23%) had consumed aspirin within 24 h of the procedure, and most of them (82%) used aspirin on a daily basis. Transbronchial biopsies were performed, and the bleeding incidence was compared between the groups.

RESULTS

A total of 57 patients (4.7%) experienced procedure-related bleeding. Minor bleeding occurred in 5 of 285 patients (1.8%) taking aspirin and in 27 of 932 control patients (2.9%; not significant). Moderate bleeding was seen in 3 of 285 patients (1.1%) in the aspirin group and in 13 of 932 patients (1.4%) in the control group (not significant). Major bleeding occurred in only 9 patients, 2 of 285 (0.9%) in the aspirin group and 7 of 932 (0.8%) in the control group (not significant). All bleeding was controlled by endoscopic means, and there were no fatalities and no need for blood transfusions.

CONCLUSIONS

We conclude that the risk of severe bleeding after transbronchial lung biopsy is small (ie, < 1%) and that the use of aspirin is not associated with any increased risk of bleeding.

Should Aspirin Therapy be Withheld before Insertion and/or Removal of a Permanent Peritoneal Dialysis Catheter?

The necessity of withdrawal of aspirin [acetylsalicylic acid (ASA)] for fear of perioperative or postoperative bleeding in patients about to undergo surgery is as yet controversial. In this study we prospectively evaluated the effect of ASA on postoperative bleeding in end-stage renal failure patients who underwent insertion, removal, and/or replacement of a peritoneal dialysis (PD) catheter at our institution from November 1999 to March 2001. During the study period 52 of the above procedures were consecutively performed in 46 patients. Patients whose catheters were removed as a result of refractory peritonitis were excluded from the study. In all cases the PD catheter used was the coiled two-cuff Tenckhoff (NIPRO™, Manchester, GA) catheter and the surgery was performed in the operating room under local anesthesia. No drains were left in the operating wound. Postoperative bleeding (wound hematoma or persistent oozing from the incision or exit site) was classified as either minor (requiring no professional intervention and/or blood replacement) or major [necessitating blood transfusion (≥1 unit red blood cells). Of the 52 procedures 29 (in 24 patients) were performed while the patient was receiving aspirin at the time of operation (aspirin group). The remaining 23 were without aspirin and constituted the control group. ASA dose was 100 mg/day in all but three who were on buffered ASA (325 mg/day). The groups were well matched with regard to age; sex; mean residual renal function; and preoperative international normalized ratio, activated partial thromboplastin time, and platelet count. In no case was there significant intraoperative bleeding. There were five (17.2%) and three (13.0%) minor bleeds in the aspirin group and control group, respectively. One major bleed occurred in the control group ending in an exploratory laparotomy. Of the nine bleeding complications six were observed after catheter removal. From these data we conclude that PD catheter insertion/removal can be safely performed under conventional low-dose aspirin therapy.

The effect of clopidogrel in combination with aspirin when given before coronary artery bypass grafting

OBJECTIVES

This study was designed to evaluate the effect of preoperative clopidogrel on coronary artery bypass graft surgery (CABG) outcomes.

BACKGROUND

Clopidogrel in combination with aspirin, given before percutaneous coronary intervention, has become the standard for stent thrombosis prevention. Some premedicated patients, however, are found to have surgical disease on angiography, and irreversible platelet inhibition becomes a concern for upcoming CABG.

METHODS

We prospectively studied 224 consecutive patients undergoing nonemergent first-time CABG, and compared those with preoperative clopidogrel exposure within seven days (n = 59) to those without exposure (n = 165).

RESULTS

The groups were comparable in age, gender, body surface area, preoperative hematocrit, preoperative prothrombin time and prior myocardial infarction. The clopidogrel group had higher 24-h mean chest tube output (1,224 ml vs. 840 ml, p = 0.001), and more transfusions of red blood cells (2.51 U vs. 1.74 U, p = 0.036), platelets (0.86 U vs. 0.24 U, p = 0.001) and fresh frozen plasma (0.68 U vs. 0.24 U, p = 0.015). Moreover, reoperation for bleeding was 10-fold higher in the clopidogrel group (6.8% vs. 0.6%, p = 0.018). The clopidogrel group also had less extubation within 8 h (54.2% vs. 75.8%, p = 0.002) and a trend towards less hospital discharge within five days (33.9% vs. 46.7%, p = 0.094).

CONCLUSIONS

Clopidogrel in combination with aspirin before CABG is associated with higher postoperative bleeding and morbidity. These findings raise concern regarding the routine administration of clopidogrel before anticipated coronary stent implantation.

Aspirin and postoperative bleeding after coronary artery bypass grafting

OBJECTIVE

To evaluate the relationship between aspirin ingestion and postoperative bleeding complications, and to test the hypothesis that there is a subset of patients who are aspirin hyperresponders with a proclivity toward platelet dysfunction.

SUMMARY BACKGROUND DATA

Despite numerous retrospective and prospective analyses, it is still controversial as to whether aspirin ingestion before coronary artery bypass grafting (CABG) is associated with significant postoperative bleeding.

METHODS

Between January 1995 and December 1999, the records of 2,606 consecutive patients undergoing CABG were reviewed to identify patients with a history of aspirin ingestion up until the time of surgery. Aspirin ingestion was correlated with postoperative blood transfusion using multivariate analysis. In a subset of preoperative aspirin users (n = 40), bleeding times were measured before and after aspirin use. Flow cytometry was performed in another cohort of patients with known heart disease (n = 30) to determine the effect of aspirin on platelet surface receptors.

RESULTS

During the 5-year study period, 63% of the CABG patients were identified as aspirin users. Among these, 23.1% required blood transfusions compared with 19% for the nonusers. Non-red blood cell transfusions were more common in aspirin users, as was reexploration for bleeding. Stratification of these results according to the frequency of aspirin use showed that aspirin is an independent multivariate predictor of postoperative blood transfusion only in high-risk patients. In the prospective studies, aspirin treatment resulted in a significant increase in the template bleeding time, an increase in platelet PAR-1 thrombin receptor activity, and a decrease in the binding of platelets to monocytes.

CONCLUSIONS

The findings support the hypothesis that aspirin is associated with a greater likelihood of postoperative bleeding. A platelet function testing algorithm that combines preoperative risk factor assessment, template bleeding times, and flow cytometry may allow the identification of aspirin hyperresponders who are at increased risk for bleeding.

[Does the time between preoperative interruption of aspirin intake and operation influence postoperative blood loss and transfusion requirement in coronary artery bypass graft?]

OBJECTIVE

Impact of the interval between interruption of aspirin intake and surgery on postoperative bleeding and transfusion in coronary artery bypass graft (CABG), with extracorporeal circulation (ECC).

STUDY DESIGN

Retrospective study.

PATIENTS AND METHODS

Four hundred and twelve patients having undergone CABG were retrospectively reviewed. Three groups were evaluated according to the length of the interval defined above: Group I (< 3 days), Group II (3-7 days), Group III (> 7 days or without aspirin intake). Postoperative blood loss at 3rd, 6th, 12th, and 24th hour and transfusion requirements were assessed for the 3 groups. Aprotinin (low dose, 2 M KIU) was systematically included in the priming of the ECC circuit.

RESULTS

There were no significant differences among groups for weight, size, duration of ECC, and number of bypasses. No significant correlation was noted among the 3 groups for postoperative blood loss and transfusion. Multivariate analysis showed that factors associated to a higher risk of excessive bleeding were ECC duration and number of arterial grafts. Factors associated with a higher risk of transfusion were: emergency, minimum patient temperature during ECC, weight and preoperative haemoglobin level. Aspirine intake was not associated with an increase of bleeding or transfusion.

CONCLUSION

Our study showed that in our practice using systematic low dose of aprotinin when priming the ECC circuit, aspirin did not significantly increase bleeding or transfusion requirements in CABG with ECC, whatever the interval between interruption of aspirin intake and surgery. Consequently, in our practice, aspirin intake is interrupted on hospitalisation, one day before surgery.

The efficacy and safety of perioperative antiplatelet therapy

Widespread adoption of the antiplatelet agents into everyday clinical practice has revolutionized contemporary care of the cardiovascular patient. Major adverse cardiovascular events including death, myocardial infarction, stroke, and recurrent angina have all been shown to be significantly decreased when these agents are employed in the treatment of coronary atherosclerosis, acute coronary syndromes, myocardial infarction, and in the setting of percutaneous coronary intervention. As a growing number of patients on antiplatelet therapy are undergoing various surgical procedures, the potential risks and benefits these drugs pose perioperatively will become increasingly important. Available data indicate that, when used appropriately, these drugs can be used safely prior to surgery. Efficacy in improving surgical outcomes and in preventing adverse cardiovascular events postoperatively has also been demonstrated. The purpose of this review is to examine the perioperative safety and efficacy of the most widely used antiplatelet agents: aspirin; the thienopyridine clopidogrel; and the glycoprotein (GP) IIb/IIIa inhibitors abciximab, eptifibatide, and tirofiban. This information, coupled with emerging platelet monitoring techniques, may help provide additional assistance to the clinician to manage therapy and guide appropriate timing of both cardiac and noncardiac surgery.

The effect of preoperative aspirin-free interval on red blood cell transfusion requirements in cardiac surgical patients

OBJECTIVE

To compare red blood cell transfusion in first-time coronary artery surgery patients who stopped taking aspirin < or = 2 days, 3 to 7 days, or >7 days preoperatively.

DESIGN

Observational study.

SETTING

University-affiliated teaching hospital.

PARTICIPANTS

Adult patients (n = 797) undergoing first-time coronary artery surgery on cardiopulmonary bypass who were not receiving other anticoagulant or antiplatelet drugs before surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were divided into 4 groups based on days since last ingestion of aspirin. Blood products transfused in the groups were (aspirin < or =2 days) (n = 140) 2.2 +/- 4 U of red cell concentrate (RCC) (mean +/- SD), 1.4 +/- 3 U of fresh frozen plasma (FFP), and 2.7 +/- 6 U of platelets; (aspirin 3 to 5 days) (n = 255), 1.5 +/- 2 U of RCC, 0.8 +/- 2 U of FFP, and 1.6 +/- 4 U of platelets; (aspirin 6 to 7 days) (n = 215), 1.6 +/- 3 U of RCC, 0.9 +/- 3 U of FFP, and 1.5 +/- 3 U of platelets; and (aspirin >7 days) (n = 187), 1.3 +/- 2 U of RCC; 0.6 +/- 2 U of FFP, and 0.9 +/- 2 U of platelets.

CONCLUSION

Patients who stop taking aspirin < or =2 s preoperatively have increased allogenic red blood cell transfusion requirements perioperatively. Patients who stop taking aspirin 3 to 7 days preoperatively have little or no increased requirement for allogenic red blood cell transfusion.

Effect of clopidogrel on bleeding after coronary artery bypass surgery

OBJECTIVE

Platelet dysfunction is a common cause of bleeding after coronary artery bypass graft surgery. This study explores the effects of clopidogrel on bleeding complications after coronary artery bypass graft surgery.

DESIGN

Prospective observational study of patients undergoing coronary artery bypass graft.

SETTING

Tertiary care center.

PATIENTS

A total of 247 patients undergoing coronary artery bypass graft surgery.

INTERVENTIONS

None.

MEASUREMENTS

Primary end point was need for reexploration secondary to bleeding. Secondary end points included need for transfusion of blood products and chest tube output.

MAIN RESULTS

Eight (3.3%) of 247 patients required reexploration secondary to bleeding. Clopidogrel recipients had higher incidence of reexploration for bleeding (9.8 vs. 1.6, p =.01) with an odds ratio of 6.9 (95% confidence interval, 1.6-30). Clopidogrel also increased the percentage of patients receiving packed red blood cell transfusion (72.6 vs. 51.6%, p =.007), the number of packed red blood cell units (3 vs. 1.6, p =0.0004), and the number of cryoprecipitate units (2.4 vs. 1.2, p =.04) transfused after coronary artery bypass graft surgery. Among clopidogrel recipients, a trend for increased transfusion of platelet units (4.3 vs. 1.7, p =.05) and fresh frozen plasma units (1.1 vs. 0.6, p =.08) also was found.

CONCLUSIONS

Preoperative use of clopidogrel in combination with aspirin is associated with increased need for surgical reexploration as well as risk of packed red blood cell and cryoprecipitate transfusions after coronary artery bypass graft surgery.

A standardized multidisciplinary approach reduces the use of allogeneic blood products in patients undergoing cardiac surgery

PURPOSE

Individual and institutional practices remain an independent predictor factor for allogeneic blood transfusion. Application of a standardized multidisciplinary transfusion strategy should reduce the use of allogeneic blood transfusion in major surgical patients.

METHODS

This prospective non randomized observational study evaluated the effects of a standardized multidisciplinary transfusion strategy on allogeneic blood products exposure in patients undergoing non-emergent cardiac surgery. The developed strategy involved a standardized blood conservation program and a multidisciplinary allogeneic blood transfusion policy based mainly on clinical judgement, not only on a specific hemoglobin concentration. Data obtained in a first group including patients operated from September 1997 to August 1998 (Group pre: n=321), when the transfusion strategy was progressively developed, were compared to those obtained in a second group, including patients operated from September 1998 to August 1999 (Group post: n=315) when the transfusion strategy was applied uniformly.

RESULTS

Patient populations and surgical procedures were similar. Patients in Group post underwent acute normovolemic hemodilution more frequently, had a higher core temperature at arrival in the intensive care unit and presented lower postoperative blood losses at day one. Three hundred forty units of packed red blood cells were transfused in 33% of the patients in Group pre whereas 161 units were transfused in 18% of the patients in Group post (P <0.001). Pre- and postoperative hemoglobin concentrations, mortality and morbidity were not different among groups.

CONCLUSION

Development of a standardized multidisciplinary transfusion strategy markedly reduced the exposure of cardiac surgery patients to allogeneic blood.