Hazards of aspirin withdrawal before transurethral prostatectomy

Special care dentistry for general dental practice

Although special care dentistry (SCD) is a fairly recent specialty, the principles and practice of SCD have been developed since the 1980s. Shared care of these patients with general dental practitioners remains vital to ensure that comprehensive care is provided. This article aims to discuss some of the patient groups commonly seen in SCD clinics and give an insight into the varied complex medical and social aspects of care which are managed as part of providing appropriate, safe and holistic care.

CLINICAL RELEVANCE

Many patients who currently fall under the remit of special care dentistry could be treated safely in general dental practice. This article acts as an introduction to special care dentistry for general dental practitioners.

Antiplatelet drugs and the perioperative period: What every urologist needs to know

Antiplatelet agents like aspirin and clopidogrel are widely used for indications ranging from primary and secondary prevention of myocardial infarction or stroke to prevention of coronary stent thrombosis after percutaneous coronary interventions. When patients receiving antiplatelet drugs are scheduled for surgery, urologists commonly advise routine periprocedural withdrawal of these drugs to decrease the hemorrhagic risks that may be associated if such therapy is continued in the perioperative period. This approach may be inappropriate as stopping antiplatelet drugs often exposes the patient to a more serious risk, i.e. the risk of developing an arterial thrombosis with its potentially fatal consequences. Moreover, it has been seen that the increase in perioperative bleeding if such drugs are continued is usually of a quantitative nature and does not shift the bleeding complication to a higher risk quality. We, in this mini review, look at the physiological role and pathological implications of platelets, commonly used antiplatelet therapy and how continuation or discontinuation of such therapy in the perioperative period affects the hemorrhagic and thrombotic risks, respectively. Literature on the subject between 1985 and 2008 is reviewed. The consensus that seems to have emerged is that the policy of routine discontinuation of antiplatelet drugs in the perioperative period must be discouraged and risk stratification must be employed while making decisions regarding continuation or temporary discontinuation of antiplatelet therapy. Although antiplatelet drugs may be discontinued in patients at a low risk for an arterial thrombotic event, they must be continued in patients where the risks of bleeding and complications related to excessive bleeding are less than the risks of developing arterial thrombosis.

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.

Peri-operative management of anti-platelet agents

BACKGROUND

Increasing numbers of patients treated with anti-platelet agents are presenting for non-cardiac surgery. We examined the peri-operative management of anti-platelet therapy in patients undergoing elective non-cardiac surgery and the process by which patients received instructions.

METHODS

We interviewed and collected outcome data on 213 consecutive patients aged > or = 45 years presenting for elective non-cardiac surgery at our institution over a 6-week period regarding the peri-operative management of anti-platelet and warfarin therapy.

RESULTS

Anti-platelet therapy was prescribed in 22.5% and warfarin in 5.2% of the study subjects. Aspirin was stopped peri-operatively in 55.3%, while clopidogrel was stopped in the sole patient treated with this. The frequency of anti-platelet agent discontinuation was similar for major and minor surgery. Warfarin was discontinued prior to surgery in all cases. Only 54.2% of those treated with anti-platelet therapy recalled being given instruction regarding pre-operative management of their anti-platelet therapy compared with 90.9% of patients treated with warfarin (P= 0.04). In the absence of instructions, a number of patients made their own decision to stop their aspirin pre-operatively. Post-operatively, only 37% recalled receiving instructions regarding restarting anti-platelet therapy. As a result, three patients failed to do so. In contrast, all those treated with warfarin received clear post-operative instructions.

CONCLUSION

Peri-operative anti-platelet management and communication with patients appears to be sub-optimal. There is a need for standardized processes whereby informed decisions regarding peri-operative anti-platelet therapy are made and communicated clearly to the 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.

The management of aspirin in transurethral prostatectomy: current practice in the UK

INTRODUCTION

Stopping aspirin prior to transurethral prostatectomy (TURP) may minimise peri-operative blood loss, but it may also increase the risk of a significant cardiovascular event. There are no guidelines on the management of aspirin in TURP. This study sought to determine the variation in the peri-operative management of transurethral prostatectomy (TURP) patients that are taking aspirin.

MATERIALS AND METHODS

A questionnaire was sent to 444 consultant urologists in the UK from a list obtained from the British Association of Urologists. This resulted in 290 anonymous replies (65%), of which 287 were suitable for analysis.

RESULTS

Of these 287 urologists, 178 (62%) ask patients to stop aspirin prior to TURP. Aspirin is stopped 9.8 days (median, 10 days; range, 2-30 days) prior to surgery, and recommenced 8.8 days (median, 7 days; range, 1-42 days) after surgery. In those that stop aspirin, 62% will stop aspirin in all patients, regardless of the indication, and 40% will cancel a TURP if aspirin use has inadvertently continued. Of the 287 urologists, 109 (38%) do not stop aspirin.

CONCLUSIONS

There is a wide variation in the management of aspirin in TURP patients in the UK. Aspirin is being stopped in patients at high risk of serious cardiovascular disease, often for longer than necessary. There is a need for multidisciplinary guidelines to reduce variation in practice.

Low-dose aspirin for secondary cardiovascular prevention - cardiovascular risks after its perioperative withdrawal versus bleeding risks with its continuation - review and meta-analysis

OBJECTIVES

Low-dose aspirin given for secondary prevention of cardiovascular disease is frequently withdrawn prior to surgical or diagnostic procedures to reduce bleeding complications. This may expose patients to increased cardiovascular morbidity and mortality. Aim of the study was to review and quantify cardiovascular risks because of periprocedural aspirin withdrawal and bleeding risks with the continuation of aspirin.

METHODS

We screened MEDLINE (January 1970-October 2004) with additional manual cross-referencing for clinical studies, surveys on the opinions of doctors and guidelines.

RESULTS

Studies reporting the relative risk of acute cardiovascular events after aspirin withdrawal when compared with its continuation were not found. However, retrospective investigations revealed that aspirin withdrawal precedes up to 10.2% of acute cardiovascular syndromes. The time interval between discontinuation and acute cerebral events was 14.3 +/- 11.3 days, 8.5 +/- 3.6 days for acute coronary syndromes, and 25.8 +/- 18.1 days for acute peripheral arterial syndromes (P < 0.02 versus acute coronary syndromes). On aspirin-related bleeding risks, we obtained 41 (12 observational retrospective, 19 observational prospective, 10 randomized) studies, reporting on 49 590 patients (14 981 on aspirin). Baseline frequency of bleeding complications varied between 0 (skin lesion excision, cataract surgery) and 75% (transrectal prostate biopsy). Whilst aspirin increased the rate of bleeding complications by factor 1.5 (median, interquartile range: 1.0-2.5), it did not lead to a higher level of the severity of bleeding complications (exception: intracranial surgery, and possibly transurethral prostatectomy). Surveys amongst doctors on the management of this problem demonstrate wide variations. Available guidelines are scarce and in part contradictory.

CONCLUSIONS

Only if low-dose aspirin may cause bleeding risks with increased mortality or sequels comparable with the observed cardiovascular risks after aspirin withdrawal, it should be discontinued prior to an intended operation or procedure. Controlled clinical studies are urgently needed.

Extracorporeal shockwave lithotripsy in patients treated with antithrombotic agents

PATIENTS AND METHODS

Between January 1996 and December 1999, 749 patients underwent electromagnetic SWL. Among them, 23 patients, 19 with renal and 4 with ureteral stones, were receiving antithrombotic drugs (aspirin, ticlopidine, dipyridamole). According to the cardiologist and hematologist, we divided these patients into two groups: Group 1 had a low thromboembolic risk (previous myocardial infarction), and Group 2 had a high thromboembolic risk (aortocoronary bypass, atrial fibrillation, cerebrovascular disease, peripheral occlusive arterial disease). Group 1 patients discontinued their antiplatelet therapy 8 days prior to SWL to permit a sufficient number of functioning platelets to remain. Group 2 patients suspended antiplatelet therapy, and unfractioned heparin 5000 IU tid (8 a.m., 4 p.m., and 12 p.m.) was administered for the 8 days prior to SWL. On the ninth day of withdrawal, SWL was performed in all patients. Close follow-up was performed during the postoperative period (hemoglobin, hematocrit, kidney ultrasonography, plain abdominal film). The antithrombotic therapy was restored in all patients within 10 to 14 days of withdrawal.

RESULTS

Hematomas and thromboembolic events were not observed. At 3 months' follow-up, 14 patients (61%) were stone free, 3 (13%) had <4-mm fragments, and 6 (26%) had >4-mm residual fragments.

CONCLUSION

Our schedules for the suspension or substitution of antithrombotic therapy, although tested in a small number of patients, allowed us to perform SWL without hemorrhagic or thromboembolic complications.