warfarin v. dabigatran RE-LY trial

Intracranial Hemorrhage in Atrial Fibrillation Patients During Anticoagulation With Warfarin or Dabigatran: The RE-LY Trial; Hart RG, Diener HC, Yang S, Connolly SJ, Wallentin L, Reilly PA, Ezekowitz MD, Yusuf S; Stroke (Apr 2012)

BACKGROUND AND PURPOSE: Intracranial hemorrhage is the most devastating complication of anticoagulation. Outcomes associated with different sites of intracranial bleeding occurring with warfarin versus dabigatran have not been defined. METHODS: Analysis of 18 113 participants with atrial fibrillation in the Randomized Evaluation of Long-term anticoagulant therapY (RE-LY) trial assigned to adjusted-dose warfarin (target international normalized ratio, 2-3) or dabigatran (150 mg or 110 mg, both twice daily). RESULTS: During a mean of 2.0 years of follow-up, 154 intracranial hemorrhages occurred in 153 participants: 46% intracerebral (49% mortality), 45% subdural (24% mortality), and 8% subarachnoid (31% mortality). The rates of intracranial hemorrhage were 0.76%, 0.31%, and 0.23% per year among those assigned to warfarin, dabigatran 150 mg, and dabigatran 110 mg, respectively (P<0.001 for either dabigatran dose versus warfarin). Fewer fatal intracranial hemorrhages occurred among those assigned dabigatran 150 mg and 110 mg (n=13 and n=11, respectively) versus warfarin (n=32; P<0.01 for both). Fewer traumatic intracranial hemorrhages occurred among those assigned to dabigatran (11 patients with each dose) compared with warfarin (24 patients; P<0.05 for both dabigatran doses versus warfarin). Independent predictors of intracranial hemorrhage were assignment to warfarin (relative risk, 2.9; P<0.001), aspirin use (relative risk, 1.6; P=0.01), age (relative risk, 1.1 per year; P<0.001), and previous stroke/transient ischemic attack (relative risk, 1.8; P=0.001). CONCLUSIONS: The clinical spectrum of intracranial hemorrhage was similar for patients given warfarin and dabigatran. Absolute rates at all sites and both fatal and traumatic intracranial hemorrhages were lower with dabigatran than with warfarin. Concomitant aspirin use was the most important modifiable independent risk factor for intracranial hemorrhage.

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Dose-dependent effect of early antiplatelet therapy in acute ischaemic stroke; Meves SH, Overbeck U, Endres HG, Krogias C, Neubauer H; Thrombosis and Haemostasis 107 (1), (Dec 2011)

Antiplatelet agents are essential in treating patients with acute ischaemic stroke (AIS) to prevent recurrent ischaemic events. The aim of this study was to evaluate the effectiveness of early antiplatelet therapy with different aspirin (ASA) dosages in patients with AIS. This observational study included 454 patients with AIS in whom antiplatelet treatment was initiated. The antiplatelet effect was determined by whole blood aggregometry within 48 hours after antplatelet therapy was initiated. An impedance change exceeding 0 Ω after stimulation with arachidonic acid was defined as ASA low response (ALR) and ≥5 Ω in ADP-stimulated specimen as clopidogrel LR. Of the study group 53.5% patients were treated with 200 mg ASA orally, 27.5% with 500 mg ASA intravenously, 8.6% with 100 mg ASA orally, and 7.7% with 75 mg clopidogrel. A dose-dependent antiplatelet effect of ASA treatment was found: 18.4% of patients with 500 mg ASA intravenously were ALR, in contrast to 32.5% on 200 mg and 35.9% on 100 mg ASA orally. Clopidogrel treatment without a loading dose resulted in a high proportion of LR (45.7%). Using the propensity score method revealed a three times higher risk for ALR for patients treated with ASA 200 mg [odds ratio 2.99 (1.55-5.79)] compared to treatment with ASA 500 mg. In conclusion, initiating antiplatelet therapy in patients with AIS resulted in a dose-dependent insufficient platelet inhibitory effect. Our findings suggest using a loading dose of 500 mg ASA intravenously as this seems to be favourable when a sufficient early platelet inhibitory effect is wanted.

comment- debate over aspirin dose never ends.  However, we treat patients, not lab tests and it would be interesting to know if there were any clinical effects or side effects of high v. low dose aspirin

dual antiplatelet therapy for 7 days in intracranial occlusive disease

The effectiveness of dual antiplatelet treatment in acute ischemic stroke patients with intracranial arterial stenosis: a subgroup analysis of CLAIR study; the CLAIR Study Investigators; International Journal of Stroke (Aug 2012)

BACKGROUND: Dual antiplatelet therapy with clopidogrel and aspirin reduces the presence and number of microembolic signals in patients with large artery disease. However, whether it is effective in patients with intracranial disease alone remains uncertain. We performed a subgroup analysis of the The CLopidogrel plus Aspirin for Infarction Reduction (CLAIR in acute stroke or transient ischemic attack patients with large artery stenosis and microembolic signals) study of only patients with intracranial occlusive disease, excluding those with extra cranial disease. METHODS: CLAIR was a randomized-controlled, open-label, multicenter clinical trial with blinded outcome evaluation, which recruited patients with symptoms of ischemic stroke or transient ischemic attack within seven-days of onset, with large artery stenosis verified by transcranial Doppler and carotid ultrasound, and with microembolic signals detected by transcranial Doppler recording. All patients were randomized to receive clopidogrel plus aspirin daily for seven-days (dual treatment), or aspirin alone for seven-days (monotherapy). Repeated transcranial Doppler recordings for microembolic signals were made on day one, two, and seven. This subgroup study only analyzed the patients with purely intracranial large artery disease and excluded those with extra cranial stenosis. RESULTS: There were 70 patients recruited with purely intracranial stenosis, 34 in the dual treatment group and 36 in the monotherapy group. The proportion of the patients with positive emboli at day seven in the dual treatment group was significantly lower than that in the monotherapy group (relative risk reduction 56·5%, 95% confidence interval 2·5-80·6; P = 0·029). The number of emboli in the dual treatment group decreased significantly at day two (P = 0·043) and day seven (P = 0·018) compared with the monotherapy group. After adjustment for the number of emboli at day one, the effect of dual treatment was still significant for the reduction of presence (relative risk reduction 56·0%; 95% confidence interval 5·4-79·6; P = 0·036) and number (adjusted mean difference -0·9; 95% confidence interval -1·5 to -0·3; P = 0·004) of positive emboli at day seven. CONCLUSIONS: Dual treatment with clopidogrel and aspirin for seven-days is more effective than aspirin alone to reduce microembolic signals in patients with intracranial arterial stenosis.

Suggestion AGAINST warfarin after 3 months post maze procedure

The impact of CHADS(2) score on late stroke after the Cox maze procedure; Pet M, Robertson JO, Bailey M, Guthrie TJ, Moon MR, Lawton JS, Rinne A, Damiano RJ, Maniar HS; Journal of Thoracic and Cardiovascular Surgery (Jul 2012)

OBJECTIVE: The Heart Rhythm Society, European Heart Rhythm Association, and European Cardiac Arrhythmia Society jointly recommend indefinite warfarin anticoagulation in patients with CHADS(2) (congestive heart failure, hypertension, age, diabetes, and stroke) score of at least 2 who have undergone ablation for atrial fibrillation. This study determined the impact of CHADS(2) score on risk of late stroke or transient ischemic attack after the performance of a surgical Cox maze procedure. METHODS: A retrospective review of 433 patients who underwent a Cox maze procedure at our institution was conducted. Three months after surgery, warfarin was discontinued regardless of CHADS(2) score if the patient showed no evidence of atrial fibrillation, was off antiarrhythmic medications, and had no other indication for anticoagulation. A follow-up questionnaire was used to determine whether any neurologic event had occurred since surgery. RESULTS: Follow-up was obtained for 90% of the study group (389/433) at a mean of 6.6 ± 5.0 years. Among these patients, 32% (125/389) had a CHADS(2) score of at least 2, of whom only 40% (51/125) remained on long-term warfarin after surgery. Six patients had late neurologic events (annualized risk of 0.2%). Neither CHADS(2) score nor warfarin anticoagulation was significantly associated with the occurrence of late neurologic events. Among the individual CHADS(2) criteria, both diabetes mellitus and previous stroke or transient ischemic attack were predictive of late neurologic events. CONCLUSIONS: The risk of stroke or transient ischemic attack in patients after a surgical Cox maze procedure was low and not associated with CHADS(2) score or warfarin use. Given the known risks of warfarin, we recommend discontinuation of anticoagulation 3 months after the procedure if the patient has no evidence of atrial fibrillation, has discontinued antiarrhythmic medications, and is without any other indication for systemic anticoagulation.

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asa + plavix decreased MI's, increases fatal hemorrhages, no effect on mortality

Effect of addition of clopidogrel to aspirin on mortality: systematic review of randomized trials; Palacio S, Hart RG, Pearce LA, Benavente OR; Stroke 43 (8), 2157-62 (Aug 2012)

 

BACKGROUND AND PURPOSE In the Secondary Prevention of Small Subcortical Strokes (SPS3) trial, addition of clopidogrel to aspirin was associated with an unexpected increase in mortality in patients with lacunar strokes. We assessed the effect of the addition of clopidogrel to aspirin on mortality in a meta-analysis of published randomized trials. METHODSRandomized trials in which clopidogrel was added to aspirin in subjects with vascular disease or vascular risk factors were identified. Trials were restricted to those with a mean follow-up of ≥14 days in which both the combination of aspirin and clopidogrel was tested and mortality was reported. RESULTSTwelve trials included 90 934 participants (mean age, 63 years; 70% men; median follow-up, 1 year) with 6849 observed deaths. There was no significant increase in mortality with the combination therapy either in 4 short-term (14 days-3 months; OR, 0.93; 95% CI, 0.87-0.99) or in 7 long-term (>3 months; hazard ratio, 0.97; 95% CI, 0.91-1.04) trials after 1 long-term trial (the SPS3 trial) was excluded because of heterogeneity. Addition of clopidogrel was associated with an increase in fatal hemorrhage (OR, 1.35; 95% CI, 0.97-1.90) and a reduction in myocardial infarction (OR, 0.82; 95% CI, 0.74-0.91). CONCLUSIONSThe addition of clopidogrel to aspirin has no overall effect on mortality. The SPS3 trial results are outliers, possibly because of a lower prevalence of coronary artery ischemia. Addition of clopidogrel to aspirin increases fatal bleeding and reduces myocardial infarction. Clinical Trial Registration- URL: http//www.clinicaltrials.gov. Unique identifier: NCT00059306.

 

Comment -- metaanalysis improves our knowledge over SPS3 results which are outliers

Need for extended clopidogrel therapy after intracranial stenting

Incidence of cerebral ischemic events after discontinuation of clopidogrel in patients with intracranial aneurysms treated with stent-assisted techniques; Rossen JD, Chalouhi N, Wassef SN, Thomas J, Abel TJ, Jabbour PM, Kung DK, Hasan DM; Journal of Neurosurgery (Sep 2012)

Object: The optimal antiplatelet medication protocol for prevention of thrombotic complications after stent-assisted coil embolization of cerebral aneurysms is unclear. Early cessation of antiplatelet agents may be associated with an increased risk of cerebral ischemic events. In this study, the authors assess the incidence of stroke or transient ischemic attack (TIA) following discontinuation of a 6-week course of clopidogrel in patients with cerebral aneurysms treated with stent-assisted techniques. Methods A retrospective review was conducted in all patients with cerebral aneurysms undergoing stent-assisted coil embolization or stent-in-stent flow diversion at the University of Iowa during a 24-month period. The antiplatelet protocol was 81 mg aspirin and 75 mg clopidogrel daily for 6 weeks, followed by 325 mg aspirin daily indefinitely. The incidence of stroke or TIA was determined by a retrospective review of medical records generated during a 3-month period following discontinuation of clopidogrel. Results A total of 154 patients underwent aneurysm treatment with stent techniques during this interval. Documentation of neurological follow-up 3 months after discontinuation of a 6-week clopidogrel treatment was available in 121 (78.6%) of 154 patients. Of these 121 patients, 114 were treated with stent-assisted coil embolization and 7 with stent-in-stent flow diversion. Six patients (5%) suffered an ischemic event after cessation of clopidogrel, with 2 events occurring within the first 2 weeks. Specifically, the rate of ischemic events was 5 (4.3%) of 114 in the"stent-coil"treatment group and 1 (14.3%) of 7 in the stent-in-stent group. Treatment had been performed in the setting of a subarachnoid hemorrhage in 1 patient. Atypical aneurysm features and technical factors predisposing to thrombotic events were found in all but one of these patients. Similarly, cardiovascular risk factors were present in 5 of the 6 patients in whom ischemic events developed after clopidogrel discontinuation. Conclusions Clopidogrel discontinuation is associated with a 5% risk of ischemic events in patients treated with stent techniques. Any stroke related to clopidogrel discontinuation is avoidable, and longer treatment is therefore clearly necessary. Patients with cardiovascular risk factors, high-risk aneurysm features, and those undergoing stent-in-stent flow diversion might benefit the most from longer clopidogrel therapy.

details of preiprocedural strokes in SAMMPRIS

Detailed Analysis of Periprocedural Strokes in Patients Undergoing Intracranial Stenting in Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS); Fiorella D, Derdeyn CP, Lynn MJ, Barnwell SL, Hoh BL, Levy EI, Harrigan MR, Klucznik RP, McDougall CG, Pride GL, Zaidat OO, Lutsep HL, Waters MF, Hourihane JM, Alexandrov AV, Chiu D, Clark JM, Johnson MD, Torbey MT, Rumboldt Z, Cloft HJ, Turan TN, Lane BF, Janis LS, Chimowitz MI, for the SAMMPRIS Trial Investigators; Stroke (Sep 2012)

 

BACKGROUND AND PURPOSE: Enrollment in the Stenting and Aggressive Medical Management for Preventing Recurrent stroke in Intracranial Stenosis (SAMMPRIS) trial was halted due to the high risk of stroke or death within 30 days of enrollment in the percutaneous transluminal angioplasty and stenting arm relative to the medical arm. This analysis focuses on the patient and procedural factors that may have been associated with periprocedural cerebrovascular events in the trial. METHODS: Bivariate and multivariate analyses were performed to evaluate whether patient and procedural variables were associated with cerebral ischemic or hemorrhagic events occurring within 30 days of enrollment (termed periprocedural) in the percutaneous transluminal angioplasty and stenting arm. RESULTS: Of 224 patients randomized to percutaneous transluminal angioplasty and stenting, 213 underwent angioplasty alone (n=5) or with stenting (n=208). Of these, 13 had hemorrhagic strokes (7 parenchymal, 6 subarachnoid), 19 had ischemic stroke, and 2 had cerebral infarcts with temporary signs within the periprocedural period. Ischemic events were categorized as perforator occlusions (13), embolic (4), mixed perforator and embolic (2), and delayed stent occlusion (2). Multivariate analyses showed that higher percent stenosis, lower modified Rankin score, and clopidogrel load associated with an activated clotting time above the target range were associated (P≤0.05) with hemorrhagic stroke. Nonsmoking, basilar artery stenosis, diabetes, and older age were associated (P≤0.05) with ischemic events. CONCLUSIONS: Periprocedural strokes in SAMMPRIS had multiple causes with the most common being perforator occlusion. Although risk factors for periprocedural strokes could be identified, excluding patients with these features from undergoing percutaneous transluminal angioplasty and stenting to lower the procedural risk would limit percutaneous transluminal angioplasty and stenting to a small subset of patients. Moreover, given the small number of events, the present data should be used for hypothesis generation rather than to guide patient selection in clinical practice.Clinical Trial Registration Information

 

Comment

high risk for hemorrhagic stroke: higher percent stenosis, lower modified Rankin score, and clopidogrel loading dose.n=13

high risk for ischemic stroke:  nonsmoker, BA stenosis, DM, and older age n=19