Low-dose and high-dose acetylsalicylic acid for patients undergoing carotid endarterectomy: a randomised controlled trial. ASA and Carotid Endarterectomy (ACE) Trial Collaborators

Antithrombotic effects of aspirin on 1- or 2-level lumbar spinal fusion surgery: a comparison between 2 groups discontinuing aspirin use before and after 7 days prior to surgery

STUDY DESIGN

Retrospective clinical analysis.

OBJECTIVE

To study proper discontinuation date of aspirin in spinal fusion surgery.

SUMMARY OF BACKGROUND DATA

It is thought that excess bleeding can be normalized if aspirin intake is discontinued approximately 7 days before surgery; however, the average life span of a platelet is generally regarded to be 7 to 10 days.

METHODS

From January 2004 to December 2009, a single surgeon performed 182 cases of 1- or 2-level lumbar fusion surgical procedures. Patients who were aspirin users (n = 86) were divided into 2 groups according to the number of days prior to surgery that they discontinued their aspirin use: the aspirin 1 group discontinued their aspirin use 3 to 7 days before surgery and the aspirin 2 group discontinued their aspirin use 7 to 10 days before surgery. Ninety-six patients who did not use aspirin before surgery were selected for the control group. We retrospectively compared the several hematological parameters among the 2 aspirin groups and the control group.

RESULTS

Both the total amount of drained blood and the duration of indwelling of the drainage catheter were significantly less in the control group than in the aspirin 1 group in patients who underwent either type of 1-level fusion surgery. However, those were not significantly different between aspirin 2 group and control group in patients who underwent either type of 1-level fusion surgery. Only drainage catheter was significantly less in the control group than in the aspirin 1 group in patients who underwent 2-level fusion surgery.

CONCLUSION

Only the aspirin 1 group, wherein patients discontinued aspirin use 3 to 7 days before surgery, showed a greater drained blood and drainage catheter than the control group. If aspirin was discontinued 7 days or longer before surgery, there was no difference in the study parameters, compared with the control group.

LEVEL OF EVIDENCE

3.

Using risk models to improve patient selection for high-risk vascular surgery

Vascular surgeons frequently perform procedures aimed at limiting death, stroke, or amputation on patients who present with diseases such as aortic aneurysms, carotid atherosclerosis, and peripheral arterial occlusive disease. However, now more than ever surgeons must balance the potential benefits associated with these interventions with the risks of physiologic insult for these elderly patients, who often have significant comorbidity burdens and the potential for costly complications. In this paper, we highlight how regional and national datasets can help surgeons identify which patients are most likely to benefit from vascular operations and which patients are most likely to suffer complications in the postoperative period. By using these guidelines to improve patient selection, our risk models can help patients, physicians, and policymakers improve the clinical effectiveness of surgical and endovascular treatments for vascular disease.

Antithrombotic therapy in peripheral artery disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline focuses on antithrombotic drug therapies for primary and secondary prevention of cardiovascular disease as well as for the relief of lower-extremity symptoms and critical ischemia in persons with peripheral arterial disease (PAD).

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

The most important of our 20 recommendations are as follows. In patients aged ≥ 50 years with asymptomatic PAD or asymptomatic carotid stenosis, we suggest aspirin (75-100 mg/d) over no therapy (Grade 2B) for the primary prevention of cardiovascular events. For secondary prevention of cardiovascular disease in patients with symptomatic PAD (including patients before and after peripheral arterial bypass surgery or percutaneous transluminal angioplasty), we recommend long-term aspirin (75-100 mg/d) or clopidogrel (75 mg/d) (Grade 1A). We recommend against the use of warfarin plus aspirin in patients with symptomatic PAD (Grade 1B). For patients undergoing peripheral artery percutaneous transluminal angioplasty with stenting, we suggest single rather than dual antiplatelet therapy (Grade 2C). For patients with refractory claudication despite exercise therapy and smoking cessation, we suggest addition of cilostazol (100 mg bid) to aspirin (75-100 mg/d) or clopidogrel (75 mg/d) (Grade 2C). In patients with critical limb ischemia and rest pain unable to undergo revascularization, we suggest the use of prostanoids (Grade 2C). In patients with acute limb ischemia due to acute thrombosis or embolism, we recommend surgery over peripheral arterial thrombolysis (Grade 1B).

CONCLUSIONS

Recommendations continue to favor single antiplatelet therapy for primary and secondary prevention of cardiovascular events in most patients with asymptomatic PAD, symptomatic PAD, and asymptomatic carotid stenosis. Additional therapies for relief of limb symptoms should be considered only after exercise therapy, smoking cessation, and evaluation for peripheral artery revascularization.

Antiplatelet drugs: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

The article describes the mechanisms of action, pharmacokinetics, and pharmacodynamics of aspirin, dipyridamole, cilostazol, the thienopyridines, and the glycoprotein IIb/IIIa antagonists. The relationships among dose, efficacy, and safety are discussed along with a mechanistic overview of results of randomized clinical trials. The article does not provide specific management recommendations but highlights important practical aspects of antiplatelet therapy, including optimal dosing, the variable balance between benefits and risks when antiplatelet therapies are used alone or in combination with other antiplatelet drugs in different clinical settings, and the implications of persistently high platelet reactivity despite such treatment.

Secondary analysis of clinical trials--a cautionary note

There is concern in published reports and reviews that patients are being harmed or denied effective treatment by the use of questionable results from secondary analyses of data from clinical trials. A well-reported secondary analysis must make clear to the reader the uncertainty of the result--so clear, in fact, that it should be an obvious part of the conclusions that implementation should await confirmation as the primary outcome in an adequately powered trial. Those who write, review and publish these reports have a responsibility to ensure that reports accurately describe the sources of uncertainty, explain complex methods and their weaknesses with clarity, and convince readers to require better evidence before changing their practice.

Aspirin and Other COX-1 inhibitors

Currently available antiplatelet drugs interfere with the process of platelet activation and aggregation by selectively blocking key enzymes involved in the synthesis of platelet agonists, or membrane receptors mediating activation signals. Pharmacological interference with critical molecular pathways of platelet activation and aggregation may reduce the risk of atherothrombotic complications through mechanisms that are also responsible for an increased risk of bleeding. Acetylsalicylic acid (aspirin) represents a prototypic antiplatelet agent. The aim of this chapter is to integrate our current understanding of the molecular mechanism of action of aspirin with the results of clinical trials and epidemiological studies assessing its efficacy and safety. Moreover, the antiplatelet properties of reversible inhibitors of the same drug target will also be reviewed.

The Use of Protection Device in Landmark-wire Technique of Symptomatic Subclavian Artery Occlusion with Combined Approach via Trans-femoral vs. Trans-brachial Arteries: Technical note

PURPOSE

Since we reported about a landmark technique to reopen an occluded subclavian artery, we have faced difficulty in using protection devices in the vertebral artery to protect against thromboembolism from the reversed steal phenomenon after angioplasty and stenting. Therefore, we are presenting an optimal solution in using a protection device while recanalizing the occluded subclavian artery.

MATERIALS AND METHODS

Among 21 cases of stenting for subclavian artery steno-occlusion, we applied the landmark technique at the opposite end of an occluded segment in 4 patients and used a protection device in two patients. Because the embolic protection device was placed in the vertebral artery via the brachial artery, optimal angioplasty and stenting via the brachial route were limited. Therefore, angioplasty via the trans-brachial approach was needed to be followed by stenting through a trans-femoral approach. We estimated the safe and optimal steps for placement and retrieval of the protection devices in addition to stenting.

RESULTS

The procedure was safely performed when a stent was introduced via the femoral artery and a protection device was used via the brachial artery. However, in cases when a guidewire wasn't passed via the transfemoral route, simultaneous use of two systems via the brachial route could cause friction of devices or trapping of protection devices in a stent. When a protection device was trapped in a deployed stent, we retrieved the protection device with a 4F angiocatheter by selectively rotating the catheter tip. To avoid such procedural difficulty, we recommend using a transbrachial angioplasty followed by trans-femoral stenting while placing the protection device in the vertebral artery via the trans-brachial route.

CONCLUSION

If a guidewire is not passed through using a trans-femoral approach while performing the landmark technique, changing the stenting route from brachial to the femoral artery can be useful after securing the lumen in the occluded subclavian artery after angioplasty via the brachial artery.

Carotid stenosis: endarterectomy or angioplasty and stenting?

Atherosclerotic narrowing of the proximal internal carotid artery is an important mechanism in ischemic stroke. Optimal medical management of internal carotid stenosis includes antiplatelet agent and statin administration, blood pressure reduction, weight control, and smoking cessation. Decisions regarding the use of invasive procedures to treat carotid disease--specifically carotid endarterectomy and carotid angioplasty and stenting--must weigh the long-term risk reduction in ipsilateral ischemic stroke against the immediate intervention risks. Clinical trials evaluating the benefits of carotid endarterectomy were conducted before widespread use of statins and newer blood pressure-lowering agents such as angiotensin-receptor blockers; it is unclear what impact this may have had on trial results. Regardless, carotid endarterectomy is clearly superior to medical therapy for patients with symptomatic severe stenosis. Conversely, the benefit from endarterectomy is muted in individuals with symptomatic moderate stenosis or asymptomatic stenosis, and decisions regarding surgical intervention must incorporate surgeon proficiency and patient comorbidity. Currently, there is a lack of evidence to support the use of carotid artery angioplasty and stenting in the routine management of carotid disease. Selected patients with severe symptomatic stenosis for whom endarterectomy cannot be safely performed may still benefit from endovascular management. However, it is unlikely that asymptomatic patients or symptomatic patients with moderate stenosis considered at high risk for endarterectomy would benefit from any intervention.

Stroke prevention-surgical and interventional approaches to carotid stenosis

Extracranial carotidartery stenosis is an important cause of stroke that often needs treatment with carotid revascularization. To prevent stroke recurrence, carotid endarterectomy has been well-established for many years in treating symptomatic high- and moderate-grade stenosis. Carotid stenting is an appealing, less invasive alternative to carotid endarterectomy, and several recent trials have compared the efficacy of the 2 procedures in patients with carotid stenosis. Carotid artery stenting has emerged as an important mode of therapy for high-risk patients with symtomatic high-grade stenosis. This review focuses on the current data available that will enable the clinician to decide optimal treatment strategies for patients with carotid stenosis.

Influence of sex on outcomes of stenting versus endarterectomy: a subgroup analysis of the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST)

BACKGROUND

In the randomised Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), the primary endpoint did not differ between carotid artery stenting and carotid endarterectomy in patients with symptomatic and asymptomatic stenosis. A prespecified secondary aim was to examine differences by sex.

METHODS

Patients who were asymptomatic or had had a stroke or transient ischaemic attack within 180 days before random allocation were enrolled in CREST at 117 clinical centres in the USA and Canada. The primary outcome was the composite of stroke, myocardial infarction, or death during the periprocedural period or ipsilateral stroke within 4 years. We used standard survival methods including Kaplan-Meier survival curves and sex-by-treatment interaction term to assess the relation between patient factors and risk of reaching the primary outcome. Analyses were by intention to treat. CREST is registered with ClinicalTrials.gov, NCT00004732.

FINDINGS

Between Dec 21, 2000, and July 18, 2008, 2502 patients were randomly assigned to carotid endarterectomy (n=1240) or carotid artery stenting (n=1262), 872 (34.9%) of whom were women. Rates of the primary endpoint for carotid artery stenting compared with carotid endarterectomy were 6.2% versus 6.8% in men (hazard ratio [HR] 0.99, 95% CI 0.66-1.46) and 8.9% versus 6.7% in women (1.35, 0.82-2.23). There was no significant interaction in the primary endpoint between sexes (interaction p=0.34). Periprocedural events occurred in 35 (4.3%) of 807 men assigned to carotid artery stenting compared with 40 (4.9%) of 823 assigned to carotid endarterectomy (HR 0.90, 95% CI 0.57-1.41) and 31 (6.8%) of 455 women assigned to carotid artery stenting compared with 16 (3.8%) of 417 assigned to carotid endarterectomy (1.84, 1.01-3.37; interaction p=0.064).

INTERPRETATION

Periprocedural risk of events seems to be higher in women who have carotid artery stenting than those who have carotid endarterectomy whereas there is little difference in men. Additional data are needed to confirm whether this differential risk should be taken into account in decisions for treatment of carotid disease in women.

FUNDING

National Institute of Neurological Disorders and Stroke and Abbott Vascular Solutions (formerly Guidant).

Use of aspirin or nonsteroidal anti-inflammatory drugs increases risk for diverticulitis and diverticular bleeding

BACKGROUND & AIMS

Nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, have been implicated in diverticular complications. We examined the influence of aspirin and NSAID use on risk of diverticulitis and diverticular bleeding in a large prospective cohort.

METHODS

We studied 47,210 US men in the Health Professionals Follow-up Study cohort who were 40-75 years old at baseline in 1986. We assessed use of aspirin, nonaspirin NSAIDs, and other risk factors biennially. We identified men with diverticulitis or diverticular bleeding based on responses to biennial and supplementary questionnaires.

RESULTS

We documented 939 cases of diverticulitis and 256 cases of diverticular bleeding during a 22-year period of follow-up evaluation. After adjustment for risk factors, men who used aspirin regularly (≥2 times/wk) had a multivariable hazard ratio (HR) of 1.25 (95% confidence interval [CI], 1.05-1.47) for diverticulitis and a HR of 1.70 (95% CI, 1.21-2.39) for diverticular bleeding, compared with nonusers of aspirin and NSAIDs. Use of aspirin at intermediate doses (2-5.9 standard, 325-mg tablets/wk) and frequency (4-6 days/wk) were associated with the highest risk of bleeding (multivariable HR, 2.32; 95% CI, 1.34-4.02, and multivariable HR, 3.13; 95% CI, 1.82-5.38, respectively). Regular users of nonaspirin NSAIDs also had an increased risk of diverticulitis (multivariable HR, 1.72; 95% CI, 1.40-2.11) and diverticular bleeding (multivariable HR, 1.74; 95% CI, 1.15-2.64), compared with men who denied use of these medications.

CONCLUSIONS

Regular use of aspirin or NSAIDs is associated with an increased risk of diverticulitis and diverticular bleeding. Patients at risk of diverticular complications should carefully consider the potential risks and benefits of using these medications.

Secondary Stroke Prevention in Women

In a meta-analysis of results from 21 randomized trials comparing antiplatelet therapy with placebo in 18,270 patients with prior stroke or transient ischemic attack, antiplatelet therapy was associated with a 28% relative odds reduction in nonfatal strokes and a 16% reduction in fatal strokes, while another trial for secondary prevention with atorvastastin 80 mg showed a 16% risk reduction in time to first occurrence of stroke (adjusted hazard ratio: 0·84, 95% CI: 0·71–0·99). However, few studies have examined the sex differences regarding the efficacy of these treatments. Specifically, recent studies have reported higher rates of perioperative complications during endarterectomy in women. Nonetheless, to date, the data on the effects of carotid artery stenting in women, coming from diverse studies and meta-analyses, have been limited owing to the small number of female patients examined. Owing to this, the evidence of the benefit for women is unclear. Peculiar pathophysiological aspects of stroke, the higher stroke risk in some specific periods in life (e.g., pregnancy, puerperium and older age) and worse documented stroke outcome in women suggest that sex does matter in stroke management. Thus, future randomized controlled trials need to be sex-balanced, in order to better understand the efficacy of appropriate secondary stroke prevention therapy in women.

Antiplatelet therapy in elderly patients

With remarkable advances of medical care, the aging population is growing rapidly. Cardiovascular disease remains the leading cause of morbidity and mortality in elderly people and therefore antiplatelet therapy has been a mainstay of cardiovascular medicines for reducing and preventing cardiovascular risk in these populations. The benefits of several antiplatelet drugs in the elderly are well documented. However, there are limited data regarding the optimal use of antiplatelet agents considering the risk:benefit ratio in elderly patients, who are more vulnerable to safety issues owing to different pharmacokinetics and pharmacodynamics as compared with young patients. In this article, we review currently available evidence regarding the efficacy and safety of antiplatelet therapy (i.e., aspirin, old and new P2Y12 inhibitors and glycoprotein IIb/IIIa inhibitors) in the elderly for primary and secondary prevention strategies in cardiovascular care.

Effects of various doses of aspirin on platelet activity and endothelial function

Although aspirin has become an established medicine for cardiac and cerebrovascular diseases, the optimal dose remains unknown. We evaluated the optimal dose of aspirin on platelet activity and endothelial function by administering 11 healthy male volunteers (32 ± 6 years of age) doses of aspirin that were increased in a stepwise manner (0, 81, 162, 330 and 660 mg/day) every 3 days. Platelet activity was assessed as surface P-selectin expression (%) measured by flow cytometry and the platelet aggregation ratio. Endothelial function in the brachial artery was assessed by measuring flow-mediated dilation (FMD) before and after reactive hyperemia. Platelet aggregation and P-selectin expression were significantly and dose-dependently suppressed (81-660 mg), and the FMD ratio tended to increase from 0 to 162 mg, but decreased significantly at 660 mg. In conclusion, although aspirin suppressed platelet activity and even surface P-selectin expression, higher doses worsened endothelial-mediated arterial dilation.

A critical review of aspirin in the secondary prevention of noncardioembolic ischaemic stroke

Both secondary prevention (such as lifestyle modifications, pharmacotherapy or surgery) and an understanding of the influence of risk factors (including the different aetiologic mechanisms of cerebral ischaemia) play a pivotal role in reducing the burden of recurrent stroke. Regarding the types of preventative treatments available, variations exist across all clinical studies, including differences in target populations (including the type of cerebral ischaemia), risk factors, length of follow-up, drop-out rates and outcomes, which makes translating the results of clinical trials to individual patients difficult. However, with such limitations in mind, this critical albeit nonsystematic review, which compared aspirin with other antiplatelets and in combination with other drugs, showed that the benefit from aspirin treatment is consistently shown in ischaemic stroke, while harms are limited. Furthermore, no definite superiority is apparent across different antiplatelet therapies. Dual antiplatelet regimens may expose to a slight but measurable higher risk of haemorrhagic complications, perhaps in selective groups of patients (i.e. those with severe small-vessel disease or in selective racial groups). Based on our analysis, the indication of aspirin as the first-line choice, also recommended by several acknowledged international or national guidelines, may be confirmed. However, the complex nature of patients at risk of recurrent ischaemic stroke necessitates a comprehensive approach, which should be driven by the primary care physician, whose role is central to successful actions for secondary stroke prevention.

COX-2 Inhibition by Use of Rofecoxib or High Dose Aspirin Enhances ADP-Induced Platelet Aggregation in Fresh Blood

Aim:

Increased cardiovascular risk after use of selective or nonselective cyclooxygenase-2 (COX-2)-inhibitors might partly be caused by enhanced platelet aggregability. However, an effect of COX-2 inhibition on platelets has so far not been observed in humans.

Methods:

We tested in healthy volunteers the effect of COX-2-inhibition nearly in-vivo, i.e. immediately after and even during blood sampling.

Results:

Measurement within 2 minutes after venipuncture, but not 60 minutes later, showed that 50 mg of rofecoxib (n=12) or 500 (n=8) or 1000 (n=8) mg of aspirin increased ADP-induced platelet aggregation in a whole-blood aggregometer to, respectively, 152, 176 and 204 % of basal level (p<0.01). No significant differences in aggregability were observed after ingestion of 80 mg of aspirin (n=16), or placebo (n=8). Plasma 6-keto-PGF1α was decreased to 74 % after rofecoxib and to 76 and 70 % after 500 and 1000 mg of aspirin but did not change after low dose aspirin. Continuous photometrical measurement of aggregation in blood flowing from a cannulated vein revealed that high dose aspirin did not elicit aggregation by itself, but increased ADP-induced aggregation in proportion to the decrease in prostacyclin formation (r=0.68, p = 0.004). Since in these experiments thromboxane production was virtually absent, the enhanced aggregation after partial COX-2 inhibition was not caused by unopposed thromboxane formation.

Conclusions:

We conclude that both selective and nonselective COX-2 inhibition enhances ADP-induced platelet aggregation in humans. This effect can only be detected during or immediately after venipuncture, possibly because of the short half-life of prostacyclin.

Low patient enrollment sites in multicenter randomized clinical trials of cerebrovascular diseases: associated factors and impact on trial outcomes

Wide variability in patient enrollment among participating sites is a common phenomenon in multicenter trials. We examined stroke trial-related factors associated with the proportion of sites with low patient enrollment and the effect of these low-enrollment sites on trial outcome. We identified efficacy clinical trials enrolling patients with cerebrovascular diseases between 1980 and 2008 using an electronic database. The trials included in our analyses were multicenter randomized controlled trials (RCTs) comparing efficacy endpoints between two or more treatment groups and having >5 sites. Sites enrolling <10 patients or <2% of total trial patients were defined as low- enrollment sites. Trials were classified into tertiles based on the proportion of low-enrollment sites. Factors associated with trials that could be ascertained through a systematic review of published data were identified and examined. The association between low enrollment and a conclusive trial designation (defined by the ability to reject the primary null hypothesis either at or before target enrollment or demonstrate equivalence/noninferiority with adequate statistical power, depending on the initial design) was assessed using a multivariate logistic regression model. We identified 51 trials that met the inclusion criteria and provided information regarding patients enrolled per center. A total of 3059 participating centers enrolled a total of 53,742 trial participants; 78% of the participating sites enrolled <2% of trial participants. Trials enrolling acute stroke patients (within 24 hours of symptom onset) or those evaluating endovascular/surgical intervention had a higher proportion of low-enrollment sites (<10 patients per site). Studies with a higher proportion of low-enrollment sites were more likely to target acute stroke patients and less likely to randomize ≥1000 patients, use general efficacy endpoints, and stratify by site. There was no association between the studies with a higher proportion of low-enrollment sites and designation as a conclusive trial. A better understanding of factors associated with low-enrollment sites in clinical trials and the impact on a trial's ability to demonstrate conclusive outcomes may lead to strategies to make trial enrollments more efficient and cost-effective.

Critical appraisal of a fixed combination of esomeprazole and low dose aspirin in risk reduction

Low dose aspirin (≤325 mg) is routinely used for primary and secondary prophylaxis of cardiovascular and cerebrovascular events. The use of low dose aspirin is associated with two- to four-fold greater risk of symptomatic or complicated peptic ulcers. Risk factors associated with low dose aspirin induced gastrointestinal toxicity includes prior history of ulcer or upper gastrointestinal (GI) bleeding, concomitant use of other nonsteroidal anti-inflammatory drugs, corticosteroid or warfarin, dual antiplatelet therapy, Helicobacter pylori (H. pylori) infection, and advanced age. Esomeprazole, like other proton pump inhibitors (PPIs) is very effective in decreasing the risk of aspirin induced gastrointestinal toxicity. Although evidence to support esomeprazole or other PPIs for primary prophylaxis in aspirin induced gastrointestinal toxicity is limited, its role in secondary prophylaxis is well established.

Landmark-wire technique of symptomatic subclavian artery occlusion

SUMMARY

The landmark at the opposite end of an occluded segment can be used for probing the occluded subclavian artery to be recanalized. Using this technique in three patients with symptomatic subclavian artery occlusion, we found the landmark-wire technique to be safe and effective for reopening completely occluded subclavian arteries. We also introduced a technique in which a protective device can be safely used throughout the stenting procedure.

Antiplatelet agents and risk factors for bleeding postcarotid endarterectomy

BACKGROUND

Antiplatelet therapy has been implicated as a risk factor for wound hematoma formation after carotid endarterectomy (CEA). Given the increasing use of alternative antiplatelet drugs acting through differing inhibitory pathways, we audited the incidence of re-operation for bleeding post-CEA.

METHODS

Data were prospectively recorded on all patients undergoing CEA in Leicester, United Kingdom between November 1997 and October 2001. The data from those requiring exploration for bleeding were studied on a case-controlled basis using paired age and sex-matched controls from within the overall database. Assessment of the patients' demographics, drug history, and intraoperative and postoperative care was made.

RESULTS

A total of 448 patients were reviewed and 27 (6.03%) cases of postoperative bleeding were identified which required exploration. Despite the prevalent use of antiplatelet drugs before surgery, there was no increased risk of bleeding associated with their use identified on univariate analysis. Patients who underwent re-exploration for bleeding had a significantly greater prevalence of post-CEA hypertension (21/27 cases vs. 25/54 controls, respectively; p = 0.014). Patients who underwent surgical re-exploration for bleeding also had a greater transfusion requirement (1.33 ± 1.3 vs. 0.02 ± 0.1 units; p ≤ 0.0001) and a longer hospital stay (4.9 ± 2.2 days vs. 2.9 ± 2.3 days; p = 0.001) although there was no increase in morbidity or mortality.

CONCLUSION

The use of newer antiplatelet drugs before surgery was not associated with an increased risk of bleeding after CEA in this study. Tight control of blood pressure, both pre- and postsurgery, appears to be important, and a protocol for the management of this condition is recommended.

Aspirin dosing for the prevention and treatment of ischemic stroke: an indication-specific review of the literature

OBJECTIVE

To evaluate the efficacy of aspirin for the treatment and prevention of ischemic stroke and identify the minimum dose proven to be effective for each indication.

DATA SOURCES

PubMed and MEDLINE searches (up to January 2010) were performed to identify primary literature, using search terms including aspirin, stroke prevention, acute ischemic stroke, acetylsalicylic acid, atrial fibrillation, myocardial infarction, and carotid endarterectomy. Additionally, reference citations from publications identified were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Articles published in English were evaluated and relevant primary literature evaluating the efficacy of aspirin in the prevention of stroke was included in this review.

DATA SYNTHESIS

Antiplatelet therapy is the benchmark for the prevention of ischemic stroke. Aspirin has been proven to prevent ischemic stroke in a variety of settings. Despite the frequency at which aspirin continues to be prescribed in patients at risk of ischemic stroke, there remains confusion in clinical practice as to what minimum dose is required in various at-risk patients. A thorough review of the primary literature suggests that low-dose (50-81 mg daily) aspirin is insufficient for some indications. Acute ischemic stroke treatment requires 160-325 mg, while atrial fibrillation and carotid arterial disease require daily doses of 325 and 81-325 mg, respectively.

CONCLUSIONS

Available evidence suggests that aspirin dosing must be individualized according to indication. Recommendations provided by national guidelines at times recommend lower doses of aspirin than have been proven effective. Higher doses are indicated for stroke prevention in atrial fibrillation (325 mg) and acute ischemic stroke patients (160-325 mg). Aspirin has not yet been proven effective for primary prevention of strokes in men, and a minimum dose for these patients cannot be determined from the available data.