Impact of prior use or recent withdrawal of oral antiplatelet agents on acute coronary syndromes

Antiplatelet therapy in the perioperative period

The current practice of withdrawing aspirin 7-10 days preoperatively may be dangerous in certain groups of patients. The risk of cardiovascular events increases 3-fold after aspirin withdrawal. The average time between aspirin withdrawal and the manifestation of acute coronary syndrome is 8 to 11 days. The withdrawal of clopidogrel earlier than 4-6 weeks after bare metal stent implantation or less than 12 months after drug-eluting stent implantation is very risky and poses a high risk of stent thrombosis and high perioperative mortality. Continuing aspirin perioperatively leads to a 1.5-fold increase in perioperative bleeding complications but it does not lead to a higher severity of bleeding complications or higher mortality. The article analyzes current European and American guidelines for perioperative antiplatelet treatment and suggests an algorithm based on the guidelines to help make clinical decisions.

Clopidogrel discontinuation and platelet reactivity following coronary stenting

AIMS

Antiplatelet therapy with aspirin and clopidogrel is recommended for 1 year after drug-eluting stent (DES) implantation or myocardial infarction. However, the discontinuation of antiplatelet therapy has become an important issue as recent studies have suggested a clustering of ischemic events within 90 days of clopidogrel withdrawal. The objective of this investigation was to explore the hypothesis that there is a transient 'rebound' increase in platelet reactivity within 3 months of clopidogrel discontinuation.

METHODS AND RESULTS

In this prospective study, platelet function was assessed in patients taking aspirin and clopidogrel for at least 1 year following DES implantation. Platelet aggregation was measured using a modification of light transmission aggregometry in response to multiple concentrations of adenosine diphosphate (ADP), epinephrine, arachidonic acid, thrombin receptor activating peptide and collagen. Clopidogrel was stopped and platelet function was reassessed 1 week, 1 month and 3 months later. Thirty-two patients on dual antiplatelet therapy were recruited. Discontinuation of clopidogrel increased platelet aggregation to all agonists, except arachidonic acid. Platelet aggregation in response to ADP (2.5, 5, 10, and 20 μm) and epinephrine (5 and 20 μm) was significantly increased at 1 month compared with 3 months following clopidogrel withdrawal. Thus, a transient period of increased platelet reactivity to both ADP and epinephrine was observed 1 month after clopidogrel discontinuation.

CONCLUSIONS

This study demonstrates a transient increase in platelet reactivity 1 month after clopidogrel withdrawal. This phenomenon may, in part, explain the known clustering of thrombotic events observed after clopidogrel discontinuation. This observation requires confirmation in larger populations.

Prospective survey of secondary bleeding following anorectal surgery in a consecutive series of 1,269 patients

INTRODUCTION

As little data is available about secondary bleeding after proctological surgery, we conducted a specific survey.

PATIENTS AND METHODS

Patients operated between November 2008 and April 2009 were prospectively included. Patients were followed until last visit (day 21-28). Severity of bleeding was low (at home stay), moderate (hospitalisation for observation), or severe (transfusion, and/or homeostasis in operating room).

RESULTS

Included were 1269 patients: haemorrhoidectomy/pexy 527 (41%), fistula treatment 273 (21%), fissurectomy 197 (15%), perianal and pilonidal abscesses 124 (10%), others 148 (12%). Before surgery 78 patients were under long-term treatment with antiplatelet or anticoagulant therapy. Seventy-eight patients (6%) demonstrated 85 bleeding events. Severity rate was: low 22%, moderate 51%, and severe 27%. Ninety-five percent of events occurred before day 15. Univariate study showed increased risk after haemorrhoidopexy (P<10-3) and anticoagulant treatment (P = 0.002), decreased risk after fissurectomy and fistulotomy (P<10-3), and no relation with age, sex or operator. After multivariate study only relationship with anticoagulant treatment remained significant.

CONCLUSION

Secondary bleeding occurred in 6% of patients after proctological surgery, requiring a readmission and/or an active treatment in about 75%. Treatment with anticoagulant exposed to increased bleeding frequency.

A review of the use of common antiplatelet agents in orthopaedic practice

Antiplatelet agents are widely prescribed for the primary and secondary prevention of cardiovascular events. A common clinical problem facing orthopaedic and trauma surgeons is how to manage patients receiving these agents who require surgery, either electively or following trauma. The dilemma is to balance the risk of increased blood loss if the antiplatelet agents are continued peri-operatively against the risk of coronary artery/stent thrombosis and/or other vascular event if the drugs are stopped. The traditional approach of stopping these medications up to two weeks before surgery appears to pose significant danger to patients and may require review. This paper covers the important aspects regarding the two most commonly prescribed antiplatelet agents, aspirin and clopidogrel.

Risk of Upper Gastrointestinal Bleeding in a Cohort of New Users of Low-Dose ASA for Secondary Prevention of Cardiovascular Outcomes

The Health Improvement Network UK primary care database was used to identify a cohort of 38 077 individuals aged 50–84 years with a first prescription of low-dose acetylsalicylic acid (ASA; 75–300 mg/day) for secondary prevention of cardiovascular or cerebrovascular events during 2000–2007. From this cohort, 169 incident cases of upper gastrointestinal bleeding (UGIB) were identified. Controls with no UGIB (n = 2000) were frequency-matched to the cases by age, sex, and follow-up time. A nested case–control analysis was performed to determine risk factors associated with UGIB. The incidence of UGIB was 1.1 per 1000 person-years (95% CI, 1.0–1.3). Low-dose ASA users with a history of peptic ulcer disease had an increased risk of UGIB compared with those without (Relative Risk [RR], 4.59; 95% CI, 2.87–7.33). Concomitant use of ASA and clopidogrel (RR, 1.61; 95% CI, 0.85–3.05) or non-steroidal anti-inflammatory drugs (NSAIDs; RR, 2.92; 95% CI, 1.77–4.82) conferred an increased risk of UGIB compared with ASA monotherapy. Discontinuation of ASA therapy (RR: 0.71, 95% CI, 0.42–1.20) and PPI co-treatment given since the start of ASA therapy (RR, 0.56; 95% CI, 0.33–0.96) were associated with a reduced risk of UGIB. In conclusion, in a cohort of individuals receiving low-dose ASA for secondary prevention of cardiovascular or cerebrovascular events, patients with a history of peptic ulcer disease, or who were receiving clopidogrel or NSAIDs had an increased risk of UGIB. The prescription of PPI therapy at the initiation of low-dose ASA reduced the risk of UGIB by almost half.

One-year clinical follow-up of a registry evaluating a percutaneous revascularisation strategy combining a pre-specified simple selection process with the use of a new thin-strut bare cobalt-chromium stent

Objectives. To evaluate clinical events in a specifically selected cohort of patients with obstructive coronary artery disease (CAD), using a new generation thin-strut bare cobalt-chromium coronary stent.Methods. Patients with single- or multi-vessel, stable or unstable CAD eligible for percutaneous implantation of at least one bare cobalt-chromium stent were evaluated in a single-centre registry. Prospective pre-specified criteria for bare cobalt-chromium stent implantation in our centre were: any acute ST-elevation myocardial infarction (MI), otherwise 1) de novo coronary lesion, and 2) lesion length <20 mm, and 3) reference vessel diameter >2.6 mm, and 4) no diabetes, unless reference vessel diameter >3.5 mm. Endpoints, retrospectively collected, were death, MI and clinically driven target-lesion revascularisation (TLR) and target-vessel revascularisation (TVR) after 12 months.Results. Between September 2005 and June 2007, 712 patients (48.7% one-vessel, 29.9% two-vessel, 20% three-vessel and 1.4% left main disease; 7.9% diabetics) were treated with 800 bare cobalt-chromium stents, for stable angina (40.9%), unstable angina (20.9%) or acute ST-elevation MI (38.2%). The procedural success rate was 99.3%. Peri-procedural MI rate was 2.2% in the semi-elective group. At 12 months there were 17 deaths (2.4%), of which nine non-cardiac, 20 (2.8%) MI, 19 (2.7%) TLR and 29 (4.1%) TVR. Early and late definite stent thrombosis occurred in four (0.6%) and three (0.4%) patients, respectively.Conclusion. A strategy aimed at minimising drug-eluting stent use and combining a pre-specified simple selection process with the use of a new thin-strut bare cobalt-chromium stent is safe and effective at one-year clinical follow-up. (Neth Heart J 2010;18:486-92.).

Cangrelor: a novel P2Y12 receptor antagonist

Antiplatelet therapy is critical in the prevention of thrombotic complications of acute coronary syndrome and percutaneous coronary interventions. Current antiplatelet agents (aspirin, clopidogrel and glycoprotein IIb/IIIa antagonists) have demonstrated the capacity to reduce major adverse cardiac events. However, these agents have limitations that compromise their clinical utility. The platelet P2Y12 receptor plays a central role in platelet function and is a focus in the development of antiplatelet therapies. Cangrelor is a potent, competitive inhibitor of the P2Y12 receptor that is administered by intravenous infusion and rapidly achieves near complete inhibition of ADP-induced platelet aggregation. This investigational drug has been studied for use during coronary procedures and the management of patients experiencing acute coronary syndrome and is undergoing evaluation for use in the prevention of perioperative stent thrombosis.

Management of platelet-directed pharmacotherapy in patients with atherosclerotic coronary artery disease undergoing elective endoscopic gastrointestinal procedures

The periprocedural management of patients with atherosclerotic coronary heart disease, including those who have heart disease and those who are undergoing percutaneous coronary intervention and stent placement who might require temporary interruption of platelet-directed pharmacotherapy for the purpose of an elective endoscopic gastrointestinal procedure, is a common clinical scenario in daily practice. Herein, we summarize the available information that can be employed for making management decisions and provide general guidance for risk assessment.

Management of platelet-directed pharmacotherapy in patients with atherosclerotic coronary artery disease undergoing elective endoscopic gastrointestinal procedures

The periprocedural management of patients with atherosclerotic coronary heart disease, including those who have heart disease and those who are undergoing percutaneous coronary intervention and stent placement who might require temporary interruption of platelet-directed pharmacotherapy for the purpose of an elective endoscopic gastrointestinal procedure, is a common clinical scenario in daily practice. Herein, we summarize the available information that can be employed for making management decisions and provide general guidance for risk assessment.

Morbidity and mortality caused by cardiac adverse events after revascularization for critical limb ischemia

BACKGROUND

We assessed cardiac adverse events (AEs) after primary lower extremity arterial revascularization (LEAR) for critical lower limb ischemia (CLI) in order to evaluate the impact of cardiac AEs on the clinical outcome. We created an optimized care protocol concerning CLI patients' preoperative work-up as well as intra- and postoperative surveillance according to recent important literature and guidelines.

METHODS

We conducted a prospective analysis of clinical outcome after LEAR using patient-related risk factors, comorbidity, surgical therapy, and AEs. This cohort was divided into patients with and without AEs. AEs were categorized according to predefined standards: minor, surgical, failed revascularization, and systemic. The consequences of AEs were reoperation, additional medication, irreversible physical damage, and early death.

RESULTS

There were 106 patients (Fontaine III n=49, 46%, and Fontaine IV n=57, 56%) who underwent primary revascularization by bypass graft procedure (n=67, 63%) or balloon angioplasty (n=39, 37%). No difference in comorbidity was registered between the two groups. Eighty-four AEs were registered in 34 patients (32%). Patients experiencing AEs had significantly less antiplatelet agents (without AEs n=63, 88%, vs. with AEs n=18, 53%; p=0.000) and/or beta-blockers (without AEs n=66, 92%, vs. with AEs n=16, 47%; p=0.000) compared to patients without AEs. The two most harmful consequences of AEs were irreversible physical damage (n=3) and early death (n=8). Sixty percent (n=9) of systemic AEs were heart-related. The postprocedural mortality rate was 7.5%, with a 75% (n=6) heart-related cause of death.

CONCLUSION

AEs occur in >30% of CLI patients after LEAR. The most harmful AEs on the clinical outcome of CLI patients were heart-related, causing increased morbidity and death. Significant correlations between prescription of beta-blockers and antiplatelet agents and prevention of AEs were observed. A persistent focus on the prevention of systemic AEs in order to ameliorate the outcome after LEAR for limb salvage remains of utmost importance. Therefore, we advise the implementation of an optimized care protocol by discussing patients in a strict manner according to a predetermined protocol, to optimize and standardize the preoperative work-up as well as intra- and postoperative patient surveillance.

Gastroduodenal toxicity of low-dose acetylsalicylic acid: a comparison with non-steroidal anti-inflammatory drugs

BACKGROUND

Low-dose acetylsalicylic acid (ASA; aspirin; 75-325 mg/day) is effective for the prevention of cardiovascular events, and its use in this indication is rapidly increasing. However, the use of ASA and, indeed, other non-steroidal anti-inflammatory drugs (NSAIDs) is limited by the incidence of adverse gastroduodenal events. OBJECTIVES AND SCOPE: To review the clinical evidence for, and the pharmacodynamic basis of, ASA-induced gastroduodenal toxicity in comparison with NSAIDs, and address the question of whether low-dose ASA is 'safe' from a gastroduodenal perspective. This was a narrative, descriptive review, rather than a formal systematic review.

FINDINGS

Adverse gastroduodenal effects, which are well known to occur with NSAIDs, are also prevalent in patients receiving low-dose ASA for cardiovascular protection even at doses as low as 75 mg/day. The risk of gastroduodenal toxicity is particularly high among 'at-risk' low-dose ASA patients (aged >70 years, previous ulcer or upper gastrointestinal bleeding and users of antiplatelets or NSAIDs). There are important differences in the mechanism of ASA-induced gastroduodenal toxicity, relative to NSAIDs. These differences include the effects on the cyclooxygenase (COX)-1 isoenzyme, local effects on the gastroduodenal mucosa specific to ASA and a reduction in platelet aggregation.

CONCLUSION

Data suggest that ASA causes significant gastroduodenal damage even at the low doses used for cardiovascular protection. These effects (both systemic and possibly local) may be pharmacodynamically distinct from the gastroduodenal toxicity seen with NSAIDs. Studies are required to establish strategies for improving the tolerability of low-dose ASA, allowing patients to continue to benefit from the cardiovascular protection associated with such therapy.

Real-life management of dual antiplatelet therapy interruption: the REGINA survey

BACKGROUND

Concern about procedure-related bleeding is a major reason for premature discontinuation of dual oral antiplatelet therapy (APT); treatment cessation is detrimental in patients with coronary artery disease (CAD), especially after drug-eluting stent (DES) placement. The nationwide REGINA survey was designed to evaluate how the interruption of dual APT is managed in the 'real world'.

METHODS

Physicians (2700/4581) were randomly selected to participate in a computer-assisted telephone interview. Knowledge about DES and APT was appraised by multiple-choice questions. Strategies for temporary interruption of dual APT before an invasive or surgical procedure were evaluated using 21 scenarios, including high-risk (30 days after DES) and low-risk (18 months after DES) periods.

RESULTS

Out of 2700 practitioners, 2515 completed the interview. Rates of correct answers to basic knowledge questions ranged from 0% (dentists) to 52% (cardiologists). Unjustified total interruption of dual APT was much more frequent than expected (22.0% vs. 11.8%). A strategy of total interruption was less frequently chosen in the period of high ischemic risk compared to the low-risk period (13.7% vs. 31.1%, p<0.0001). Dual APT interruption in patients who require additional invasive cardiac or surgical procedures depended on type of physician consulted (more frequent in specialists than general practitioners or dentists), and on the physician's age and practice type (rural/private vs. urban/hospital). Correct answers were more frequently given in situations bearing a major risk, either ischemic or bleeding risk, than in those with no risk (49.2% vs. 30.2%, p<0.0001). Low-molecular-weight heparin was the substitution therapy in over two-thirds of scenarios and was associated with longer periods of APT interruption.

INTERPRETATION

Adequate management of APT in patients with intracoronary stents who undergo potentially haemorrhagic invasive procedures depends mainly on the type of physician involved and their practice rather than on a carefully weighted assessment of ischemic/bleeding risk. Our findings suggest a lack of scientific evidence, insufficient knowledge of guidelines, and poor communication between physicians managing these patients.

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.

[Patients with coronary artery stents: when and how should operations be carried out?]

Nowadays stents are implanted in over 90% of percutaneous coronary interventions. Depending on the type of stent implanted, dual antiplatelet therapy combining a cyclooxygenase inhibitor such as acetylsalicylic acid and an adenosine diphosphate receptor antagonist (thienopyridine) such as clopidogrel is required for 1-12 months. Premature termination of antiplatelet therapy during non-cardiac surgery significantly increases the risk of stent thrombosis and consequently myocardial infarction, whereas continuation of dual antiplatelet therapy during surgery increases the risk of severe bleeding. Accordingly, treatment recommendations have to be based on the individual relative risk. In cases with a high risk for major bleeding during surgery, interruption of antiplatelet therapy may be required, whereas in cases of a high risk of stent thrombosis, both antiplatelet drugs should be continued throughout surgery. Patients on dual antiplatelet therapy should be counseled by a team of anesthesiologists, surgeons and cardiologists, to devise the right point in time for the operation, the best perioperative antiplatelet therapy and the appropriate perioperative monitoring.

Perioperative management of antiplatelet agents in noncardiac surgery

It is common that patients who are scheduled for surgery are treated with antiplatelet agents (APAs) due to their wide indications. The management of these APAs in the perioperative period (acetylsalicylic acid alone, a thienopyridine alone or, in most cases, a combination of them) has a dual perspective: the risk of bleeding when the patient is operated under the effect of the APA against the risk of thrombosis if it has been withdrawn. The main challenges for the anaesthesiologist and the surgeon include patients with a coronary stent (mainly, new drug-eluting coronary stents), those undergoing urgent surgery and those undergoing high bleeding risk surgery. We review current protocols and discuss the most recent proposals for the management of APAs in patients undergoing noncardiac surgery. Current recommendations include the maintenance of aspirin if possible throughout the perioperative period, in order to limit the risks of cardiological, vascular or neurological postoperative events, although this makes it necessary to assume a small risk for haemorrhagic complications in some patients. Nevertheless, there are many circumstances that are not clear yet and, in this situation, it is crucial that patients are treated with a multidisciplinary approach (anaesthesiologists, surgeons, cardiologists and haematologists).

Aspirin noncompliance is the major cause of "aspirin resistance" in patients undergoing coronary stenting

OBJECTIVES

We investigated the hypothesis that biological aspirin "resistance" may often be related to noncompliance in patients undergoing coronary stenting.

BACKGROUND

Premature discontinuation of antiplatelet therapy has been identified as a major risk factor for stent thrombosis and prior aspirin withdrawal has been associated with poor prognosis after acute coronary syndrome.

METHODS

We prospectively investigated the occurrence of aspirin noncompliance in 136 consecutive patients undergoing coronary stenting receiving aspirin 75 mg daily. We analyzed posttreatment maximal intensity of arachidonic acid-induced platelet aggregation (AA-Ag) during hospitalization after controlled intake of aspirin and 1 month after hospital discharge. After 1 month, all "nonresponders" received controlled aspirin 75 mg and assessment of response was repeated. Aspirin nonresponse was defined by AA-Ag >30%.

RESULTS

During inhospital period, the range of AA-Ag varied from 0% to 34% with a mean value of 7.5% +/- 10%, and 4 patients (3%) were classified as nonresponders. One month after discharge, AA-Ag of the population was significantly higher than during the hospital phase (15.3 +/- 23 vs 7.5 +/- 10%, P = .0004), and 19 patients (14%) were identified as nonresponders. After controlled administration of aspirin, all but one of these nonresponders became responders and were identified as patients with noncompliance rather than biological resistance.

CONCLUSION

Aspirin resistance is rare in compliant patients using methods that directly indicate the degree of platelet cyclooxygenase inhibition. More than 10% of patients receiving aspirin for coronary stenting are noncompliant for aspirin therapy during the first month after stenting. These results suggest a need for improved education of these patients.

Differences in Managing Anticoagulants and Antiplatelets for Gastrointestinal Endoscopy between East and West

Decreasing the bleeding risk associated with gastrointestinal (GI) endoscopic procedures and minimizing the thromboembolic risk of withdrawing medications are very important for the patients taking anticoagulants and antiplatelets. Western guidelines on managing anticoagulation and antiplatelet medications in GI endoscopy suggest a polypectomy with aspirin medication or a biopsy with warfarin medication. However, Eastern endoscopists’ adherence to Western guidelines may be responsible for Easteners experiencing massive bleedings. During the cessation of drugs, it should be emphasized that Asians may be predisposed to different forms of embolism more likely to be of the cerebrovascular system, whereas Westerners more likely to be of the cardiovascular variety. To better understand the differences between the East and West, differences in drug metabolism should be considered that results in greater body weight-normalized plasma unbound clearance of drug in Easterners. Taken as a whole, different managements are required for GI endoscopy in patients on anticoagulation and/or antiplatelet medications based on differences in metabolism of drugs, risk of hemorrhage, and forms of thromboembolism.

Efficacy of esomeprazole (20 mg once daily) for reducing the risk of gastroduodenal ulcers associated with continuous use of low-dose aspirin

OBJECTIVES

Low-dose aspirin is standard treatment for prevention of cardiovascular events in at-risk patients. However, long-term administration of low-dose aspirin is associated with a greater risk of adverse events, including gastroduodenal ulcers. This study determined the efficacy of esomeprazole for reducing the risk of gastric and/or duodenal ulcers and dyspeptic symptoms in patients receiving continuous, low-dose aspirin therapy.

METHODS

Patients aged > or =60 yr, without baseline gastroduodenal ulcer at endoscopy, who were receiving aspirin 75-325 mg once daily, were randomized to esomeprazole 20 mg once daily or placebo for 26 wk. The presence of endoscopic gastric and/or duodenal ulcers and esophageal lesions was assessed at weeks 8 and 26. Upper gastrointestinal symptoms were assessed at weeks 8, 16, and 26.

RESULTS

The intention-to-treat population comprised 991 patients (esomeprazole, N = 493; placebo, N = 498). Twenty-seven patients (5.4%) in the placebo group developed a gastric or duodenal ulcer during 26 weeks' treatment compared with eight patients (1.6%) in the esomeprazole group (life-table estimates: 6.2%vs 1.8%; P= 0.0007). At 26 wk, the cumulative proportion of patients with erosive esophagitis was significantly lower for esomeprazole versus placebo (4.4% and 18.3%, respectively; P < 0.0001). At 26 wk, esomeprazole-treated patients were more likely to experience resolution of heartburn, acid regurgitation, and epigastric pain (P < 0.05).

CONCLUSIONS

Esomeprazole 20 mg once daily reduces the risk of developing gastric and/or duodenal ulcers and symptoms associated with the continuous use of low-dose aspirin in patients aged > or =60 yr without preexisting gastroduodenal ulcers.

Prothrombotic and hemorrhagic effects of aspirin

Aspirin remains the most widely used drug for prevention of vascular events. Recent observational epidemiological evidence has raised the concern that aspirin withdrawal for treatment noncompliance, surgery, or side effects can carry an increased thrombotic risk. The delay to the thrombotic event was between 7 to 30 days in most reports and most frequently 7 to 10 days. The mechanism underlying this effect remains poorly understood. Using an in vivo model of laser-induced thrombosis, aspirin injected in 1 single dose of 100 mg/kg body weight has also shown a prothrombotic activity in the rat 8 to 10 days after injection in the normal rat. The hypothesis was made that minimal concentrations of aspirin or ultra-low dose aspirin (ULDA) could induce this effect. ULDA showed prothrombotic properties in the same model of induced thrombosis that were very similar to those described after aspirin withdrawal, but the effect was observed only 1 hour after aspirin administration. This prothrombotic effect of ULDA is very similar to the effect observed after COX 2 selective inhibition with NS 398. The administration of both the selective COX 2 inhibitor and ULDA did not produce further changes. In conclusion, the prothrombotic effects described in recent observational studies are likely produced by a direct effect of aspirin, whose putative mechanism involving COX 2 inhibition remains poorly understood.

[Diagnostic flexible bronchoscopy. Recommendations of the Endoscopy Working Group of the French Society of Pulmonary Medicine]

These guidelines on flexible bronchoscopy depict important clues to be known and taken into account while practicing flexible bronchoscopy, in adult, except in emergency situations. This is a practical clarification. Safety conditions, complications, anesthesia, infectious risks, cleaning and disinfection are detailed from a review of the literature. Intensive care practice of bronchoscopy requires more attention due to higher risks patients and is discussed extensively. Standards and performances of the various sampling techniques complete this work. Indications for bronchoscopy, therapeutic and paediatric bronchoscopy are not covered in these guidelines.

[Is withdrawal of antiplatelet therapy necessary prior to skin cancer surgery?]

AIM

The aim of this study was to assess the value of discontinuing antiplatelet treatment prior to surgery for skin cancer with loss of skin of up to 10 cm in diameter. The study hypothesis postulated equivalence between discontinuation of antiplatelet therapy and continuation of these drugs during the perioperative period with regard to risk of cutaneous complications.

PATIENTS AND METHODS

This was a prospective, randomised study comparing two groups of patients on long-term antiplatelet treatment scheduled for surgery for skin carcinoma. In the first group, patients underwent surgery without change to their antiplatelet therapy while in the second, antiplatelet treatment was discontinued and substituted with either flurbiprofen or isocoagulant fractionated heparin or calcium heparin. Sixty patients took part in the study. Statistical analysis using ANOVA and Mann-Whitney non-parametric tests was performed to compare the following variables: age, sex, number of pre- and post-operative consultations, complications (haemorrhage, haematoma, separation and infection) and quality of wound healing.

RESULTS

No statistically significant difference was seen between the two groups regarding either complications or quality of wound healing.

CONCLUSION

There appear to be no rational grounds for discontinuing antiplatelet therapy in advance of skin cancer surgery involving loss of skin of up to 10 cm in diameter.