Aspirin :: contraindications
Am J Med. 2011 Sep ;124 (9):793-9 21745652
Institute of Cardiology and Center of Excellence on Aging, G. d'Annunzio University, Chieti, Italy. firstname.lastname@example.org
Prevention of atrial fibrillation-related stroke is an important part of atrial fibrillation management. However, stroke risk is not homogeneous and varies with associated morbidities and risk factors. Risk stratification schemes have been developed that categorize patients' stroke risk into classes based on a combination of risk factors. According to the calculated level of risk, guidelines recommend patients with atrial fibrillation receive antithrombotic therapy either as a vitamin K antagonist or aspirin. Despite recommendations, however, many patients with atrial fibrillation do not receive adequate thromboprophylaxis. We will discuss some of the underlying reasons, in part related to the drawbacks associated with vitamin K antagonists. These highlight the need for new anticoagulants in atrial fibrillation. The novel oral anticoagulants in development may overcome some of the limitations of vitamin K antagonists and address their underuse and safety concerns.
Most cited papers:
Aspirin for secondary prevention after acute myocardial infarction in the elderly: prescribed use and outcomes.
Cardiovascular Section, Yale School of Medicine, New Haven, CT 06520-8017, USA.
OBJECTIVES To determine how often aspirin was prescribed as a discharge medication to eligible patients 65 years of age and older who were hospitalized with an acute myocardial infarction; to identify patient characteristics associated with the decision to use aspirin; and to evaluate the association between prescription of aspirin at discharge and 6-month survival. DESIGN Observational study. SETTING All 352 nongovernment, acute care hospitals in Alabama, Connecticut, Iowa, and Wisconsin. PATIENTS 5490 consecutive Medicare beneficiaries who survived an acute myocardial infarction, were hospitalized between June 1992 and February 1993, and did not have a contraindication to aspirin. MEASUREMENTS Medical charts were reviewed to obtain information on the prescription of aspirin at discharge, contraindications, patient demographic characteristics, and clinical factors. RESULTS 4149 patients (76%) were prescribed aspirin at hospital discharge. In a multivariable analysis, an increased prescribed use of aspirin at discharge was correlated with several indicators of better overall health status (better left ventricular ejection fraction, absence of diabetes, shorter length of hospital stay, higher albumin level, and discharge to the patient's home). The prescribed use of aspirin at discharge was also associated with several specific patterns of care, including the use of cardiac procedures, beta-blocker therapy at discharge, and aspirin during the hospitalization. The prescribed use of aspirin at discharge was associated with a lower mortality rate 6 months after discharge compared with no prescribed aspirin (odds ratio, 0.77; 95% CI, 0.61 to 0.98), even after adjustment for baseline differences in demographic, clinical, and treatment characteristics between the two groups. CONCLUSIONS Aspirin was not prescribed at discharge to 24% of elderly patients who were hospitalized with an acute myocardial infarction and did not have a contraindication to aspirin. Several patient characteristics were associated with a higher risk for not being prescribed aspirin. Increasing the prescription of aspirin for these patients may provide an excellent opportunity to improve their care.
Department of Cardiovascular Medicine, Cleveland Clinic Foundation, Cleveland, OH 44195, USA. email@example.com
Department of Internal Medicine III, Hematology, Oncology, Clinical Immunology, and Infectious Diseases, University of Ulm, Germany.
Aspirin has a well established role in the prevention of arterial thrombosis. Discussion on the efficacy and safety of aspirin in the treatment and prophylaxis of thrombosis in essential thrombocythemia (ET) has become an important issue. The rationale for its use in ET comes from the observation that arterial thrombosis and platelet-mediated microcirculatory disturbances are the major causes of morbidity and mortality in ET. Experimental data have shown persistently elevated levels of thromboxane A2 (TXA2) in ET patients probably reflecting an enhanced in vivo platelet activation. Increased TXA2 biosynthesis and platelet activation in vivo in ET are selectively suppressed by repeated low doses of aspirin. ET-related symptoms such as erythromelalgia, transient neurologic and ocular disturbances are sensitive to aspirin. However, the benefit of low-dose aspirin is still uncertain in the primary prevention of thrombosis in ET. Furthermore, aspirin may unmask a latent bleeding diathesis frequently present in ET which may result in severe hemorrhagic complications. Thus, aspirin is contraindicated in ET patients with a bleeding history or a very high platelet count (> 1500 x 10(9)/L) leading to the acquisition of von Willebrand factor deficiency. If indicated, aspirin is presently used in the widely accepted low-dose regimen of 100 mg daily. However, an optimal effective dose has not yet been established. To further evaluate the efficacy and safety of aspirin in ET, prospective clinical trials are needed.
Institute of Cardiovascular and Respiratory Diseases, University of Milan, Italy.
Inflammation of the airways accompanied by eosinophil infiltration appears to play a fundamental role in the pathogenesis of bronchial asthma. Therefore, anti-inflammatory agents (at present corticosteroids, cromoglycate and nedocromil) are the first-line treatment for this condition. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin (acetylsalicylic acid) and indomethacin, however, have never been used in this setting, mainly for fear of adverse effects (e.g. severe obstructive reactions); these can occur, in a consistent number of patients as a consequence (according to the most widely accepted theory) of inhibition of prostaglandin synthesis. In a double-blind crossover placebo-controlled study involving 20 aspirin-sensitive patients with asthma, we found that oral nimesulide 100mg was well tolerated both clinically and functionally (no significant changes in forced expiratory volume in 1 second and specific airway resistance after drug intake). In a more recent study, we observed a mild obstructive reaction (easily controlled with inhaled bronchodilators) after oral administration of nimesulide 400mg to 3 patients who had previously tolerated a 100mg dose. On the basis of clinical experience, nimesulide (unlike most other NSAIDs) in the recommended doses appears to be well tolerated in aspirin-sensitive asthmatic patients. Furthermore, this distinctive anti-inflammatory agent might provide a novel approach to the treatment of bronchial asthma.
Centre for Health Services Research, University of Newcastle upon Tyne.
OBJECTIVE To record the use of secondary prophylactic drugs in patients discharged from hospital having had a myocardial infarction. DESIGN Prospective postal questionnaire survey of a random one in two sample of general practitioners in the region. SETTING The nine family practitioner committee areas within the Northern Regional Health Authority. PATIENTS Patients who had had a myocardial infarction and were discharged to their general practitioner. MAIN OUTCOME MEASURE Whether beta blockers or aspirin, or both, were given on discharge. RESULTS Of 267 patients, 158 (59%) were treated suboptimally in that they did not receive a secondary prophylactic drug to which they had no contraindication. For most patients this entailed underuse of one drug, but 17 (6%) of patients received no treatment. beta Blockers were 2.5 times less likely to be used than aspirin. Treatment was not associated with the age or sex of the patient, risk of further infarction, or hospital of discharge. CONCLUSIONS Secondary prophylaxis after myocardial infarction is practised haphazardly. It should be offered to all patients who can tolerate it, after a trial period to assess any side effects of the drugs if necessary.
University of Missouri Hospital, St. Louis, MO, USA.
BACKGROUND: Antithrombotic agents are underutilized in elderly patients with atrial fibrillation. In a peer-review audit of antithrombotic use in Missouri, rural patients were given antithrombotic therapy less often than rural patients for unclear reasons. METHODS AND RESULTS: The charts of 597 hospitalized Medicare patients discharged between October 1, 1993, and December 31, 1994, from urban and rural hospitals in Missouri were reviewed. In addition to antithrombotic therapy prescribed at the time of discharge, patient and physician information, relative contraindications to antithrombotic therapy, and risk factors for stroke were identified. Rural and urban patients were similar in terms of age, sex, and risk factors for stroke. At least one stroke risk factor was noted in 87% of rural patients and in 84% of urban patients. Urban patients were more likely to have a relative contraindication to antithrombotic therapy compared with rural patients (66% vs 54%, P =.04) but received antithrombotic therapy more often (58% vs 47%, P =.02). Cardiologists prescribed antithrombotic therapy significantly more often than noncardiologists (69% vs 52%, P =.003). CONCLUSIONS: Elderly rural patients with atrial fibrillation receive antithrombotic therapy less frequently than urban patients despite having a similar high-risk profile and fewer relative contraindications. Primary care physicians prescribe antithrombotic therapy less often than cardiologists, which is one of the reasons for this underutilization.
Current practice in the use of antiplatelet agents in the peri-operative period by UK vascular surgeons.
Department of Surgery and Northern Vascular Unit, Freeman Hospital, Newcastle upon Tyne, UK.
BACKGROUND There currently appears to be no firm consensus with regards to the use of antiplatelet agents during the peri-operative period in vascular surgical practice. METHODS A nine-part questionnaire relating to peri-operative antiplatelet use was sent to 137 ordinary members of the Vascular Surgical Society of Great Britain and Ireland (VSS-GBI). RESULTS Of the 137 questionnaires sent, 90 were returned (66%). For patients undergoing infra-inguinal bypass, carotid endarterectomy and varicose vein surgery, over 90% of vascular surgeons continue antiplatelet agents peri-operatively; however, in the case of aortic aneurysm repair, this figure is lower (77%). Three of the respondents stated that they would stop clopidogrel, but not aspirin, prior to surgery because of concerns over increased operative bleeding. In patients starting routine heparin prophylaxis against thrombosis, most surgeons opted to continue antiplatelet therapy (82%), although in patients requiring therapeutic heparin treatment, opinions were almost equally split. Most vascular surgeons (93%) would to start an alternative antiplatelet agent if a patient was intolerant of aspirin for gastrointestinal reasons. CONCLUSIONS Although the benefits of antiplatelet drugs in the long-term reduction of vascular events is established, evidence supporting their use in the peri-operative period is scarce. The general consensus of opinion from this survey suggests that most vascular surgeons do not stop antiplatelet drugs pre-operatively.
Department of Ophthalmology, St Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK.
BACKGROUND No substantial recommendations exist regarding the management of anticoagulant drugs prior to ocular surgery. Stopping anticoagulation can cause fatal emboli, but sight-threatening bleeds may occur if anticoagulation is continued. We examined the effects of anticoagulation on vitreoretinal surgery. METHODS Clinical details were prospectively entered on a database. The anticoagulant status of 541 consecutive patients undergoing vitreoretinal surgery was recorded. RESULTS Sixty patients in the study were taking aspirin and seven were taking warfarin. There were 11 cases of choroidal haemorrhage, one of which involved a warfarin user. Of 325 retinal detachment repairs, 21 (6.5%) had preoperative vitreous haemorrhages. Two of these patients were on aspirin and two were on warfarin. Sixty-six vitrectomies were performed for diabetic vitreous haemorrhages, of which nine re-bled postoperatively. One of these patients was taking warfarin. The association of warfarin with bleeding was statistically significant (relative risk 6.185). CONCLUSION Anticoagulation had no effect on the number of significant perioperative (choroidal) haemorrhages. Aspirin had little effect on bleeding during vitreoretinal surgery. Warfarin, however, was associated with bleeding complications. We suggest that aspirin should not be stopped prior to surgery. Warfarin may be stopped if the patient's thromboembolic risk is low.
The Department of Medicine, Division of Hematology/Oncology, University of Pittsburgh Medical Center, PA, USA.
Acquired inhibitors to FVIII (anti-FVIII) are uncommon in children. An acquired anti-FVIII developed in a previously healthy 4-year-old boy treated with penicillin for streptococcal pharyngitis. Aspirin prophylaxis begun for suspected rheumatic fever led to compartment syndromes of all four extremities, which resolved with high-dose FVIII and surgical decompression. Anti-FVIII in this patient, and the five additional cases identified in a survey of 160 haemophilia treatment centres, occurred at a median age of 8 years, with median initial and peak titres of 4.6 and 6.9 Bethesda Units (BU), respectively. All six presented with bleeding, including haematomas (three intramuscular, one intracranial), and ecchymoses in three. The median baseline FVIII was 0.05 U mL(-1), and the median baseline activated partial thromboplastin time (APTT) was 79.8 s. The inhibitor resolved completely in five patients (83%) within a median 5 months, after treatment with FVIII concentrate, steroids, cytoxan, methotrexate, and no treatment. The inhibitor persisted in the patient with Goodpasture's disease, despite steroids, cytoxan, cyclosporin, and intravenous gamma globulin. Aspirin therapy, in two, worsened ongoing bleeding. The association of penicillin-like drugs in this and three other cases in the literature suggest that to avoid potential catastrophic bleeding, it is prudent to obtain an APTT prior to initiating aspirin for suspected rheumatic fever. In conclusion, acquired anti-FVIII inhibitors in children may cause severe bleeding, and remit in the majority after FVIII and/or immunosuppressive therapy.
South Tyneside District Hospital, Tyne and Wear.
Atrial fibrillation (AF) is an important and independent risk factor for stroke, particularly in elderly people. The efficacy of treatment with warfarin and aspirin in primary and secondary stroke prevention in AF has been demonstrated in randomized clinical trials. In a demographic study, we examined the prevalence of AF in patients registered with a general practice in the North East of England; 91 patients with known AF were identified, 69 with chronic AF and 22 with paroxysmal AF. The mean duration of the arrhythmia was 6.43 years and the prevalence of AF increased with age. There was a high prevalence of cerebrovascular disease in AF patients. The majority of AF patients were not receiving therapy with aspirin or warfarin as primary or secondary stroke prevention. If strategies for stroke prevention in AF are to be applied to the community, general practitioners will need to play a more active part.