intracranial hemorrhage

Risk for Bleeding With Dabigatran vs Warfarin in Atrial Fibrillation

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TAKE-HOME MESSAGE

  • Investigators in this retrospective cohort study examined the incidence of bleeding in patients with atrial fibrillation who were treated with either dabigatran or warfarin. Compared with warfarin therapy, treatment with dabigatran was associated with a higher risk for any bleeding (HR, 1.30), major bleeding (HR, 1.58), and gastrointestinal hemorrhage (HR, 1.85).
  • In contrast, the risk for intracranial hemorrhage was lower in patients treated with dabigatran compared with those treated with warfarin (HR, 0.32).

ABSTRACT

IMPORTANCE

It remains unclear whether dabigatran etexilate mesylate is associated with higher risk of bleeding than warfarin sodium in real-world clinical practice.

OBJECTIVE

To compare the risk of bleeding associated with dabigatran and warfarin using Medicare data.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective cohort study, we used pharmacy and medical claims in 2010 to 2011 from a 5% random sample of Medicare beneficiaries. We identified participants as those newly diagnosed as having atrial fibrillation from October 1, 2010, through October 31, 2011, and who initiated dabigatran or warfarin treatment within 60 days of initial diagnosis. We followed up patients until discontinued use or switch of anticoagulants, death, or December 31, 2011.

EXPOSURES

Dabigatran users (n = 1302) and warfarin users (n = 8102).

MAIN OUTCOMES AND MEASURES

We identified any bleeding events and categorized them as major and minor bleeding by anatomical site. Major bleeding events included intracranial hemorrhage, hemoperitoneum, and inpatient or emergency department stays for hematuria, gastrointestinal, or other hemorrhage. We used a propensity score weighting mechanism to balance patient characteristics between 2 groups and Cox proportional hazards regression models to evaluate the risk of bleeding. We further examined the risk of bleeding for 4 subgroups of high-risk patients: those 75 years or older, African Americans, those with chronic kidney disease, and those with more than 7 concomitant comorbidities.

RESULTS

Dabigatran was associated with a higher risk of bleeding relative to warfarin, with hazard ratios of 1.30 (95% CI, 1.20-1.41) for any bleeding event, 1.58 (95% CI, 1.36-1.83) for major bleeding, and 1.85 (95% CI, 1.64-2.07) for gastrointestinal bleeding. The risk of intracranial hemorrhage was higher among warfarin users, with a hazard ratio of 0.32 (95% CI, 0.20-0.50) for dabigatran compared with warfarin. Dabigatran was consistently associated with an increased risk of major bleeding and gastrointestinal hemorrhage for all subgroups analyzed. The risk of major bleeding among dabigatran users was especially high for African Americans and patients with chronic kidney disease.

CONCLUSIONS AND RELEVANCE

Dabigatran was associated with a higher incidence of major bleeding (regardless of the anatomical site), a higher risk of gastrointestinal bleeding, but a lower risk of intracranial hemorrhage. Thus, dabigatran should be prescribed with caution, especially among high-risk patients.

More Information on Thrombolysis Benefits for Ischemic Stroke.

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Two studies using large databases provide details on timing and outcomes.

Clinical trials of thrombolysis for acute ischemic stroke typically have included fewer than 1000 patients. Two new studies involved larger datasets, allowing investigators to analyze important clinical issues in greater detail.

Saver and colleagues analyzed data from the national Get With The Guidelines–Stroke (GWTG-Stroke) database on 58,353 patients (median age, 72; 50.3% women) treated with tissue plasminogen activator (TPA) within 4.5 hours of symptom onset over a 9-year period. The median time from symptom onset to TPA administration was 144 minutes. Factors associated with earlier treatment included greater stroke severity, arrival by ambulance, and arrival during regular hours. Intracranial hemorrhage occurred in 4.9% of patients; 38.6% were discharged home. Earlier treatment, measured in 15-minute increments, was associated significantly with reduced mortality (odds ratio, 0.96), reduced intracranial hemorrhage (OR, 0.96), increased chance of independent ambulation at discharge (OR, 1.04), and increased rate of discharge to home (OR, 1.03).

The IST-3 collaborative group examined the effects of thrombolysis on 18-month quality-of-life and functional outcomes. Among more than 2300 patients from 10 countries who were randomized to usual care or thrombolysis within 6 hours of stroke, the adjusted odds of being alive and independent at 18 months were 28% greater with thrombolysis. Survival at 18 months did not differ. On a scale measuring mobility, self care, activity, pain, and anxiety, patient or caregiver reports of wellbeing improved significantly more between 6 and 18 months after stroke, and were better at 18 months, in the thrombolysis group, although anxiety was not lower.

COMMENT

The data from the large GWTG-Stroke database emphasize the importance of timely intervention for acute ischemic stroke. Currently, fewer than one third of patients are treated with thrombolysis with a door-to-needle time of <60 minutes (Stroke 2011; 42:2983). The Target: Stroke initiative of the American Heart Association/American Stroke Association aims to improve this rate to 50% in the next few years. Accelerating the pace of treatment will have multiple important benefits, including lower mortality and improved functional outcomes.

The study from the IST-3 investigators shows long-term benefits for functional status with prior thrombolytic therapy. Although multiple factors can affect health status 18 months after stroke (such as cardiac issues and infectious complications), the persisting improvements in functional status with prior thrombolytic therapy are reassuring.

When It Comes to Stroke Treatment, Just 15 Minutes Can Make a Difference.

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In patients with acute ischemic stroke, even small reductions in the time to thrombolytic therapy are associated with improved outcomes, according to a study in JAMA.

Using a national stroke registry, U.S. researchers examined outcomes among some 58,000 patients, at nearly 1400 hospitals, who received intravenous tissue plasminogen activator (tPA) within 4.5 hours after symptom onset. They found that with each 15-minute decrease in time to tPA therapy, patients were significantly less likely to die in the hospital or experience intracranial hemorrhage (odds ratio for each, 0.96). In addition, each 15-minute reduction was significantly associated with a greater likelihood to walk independently at discharge (OR, 1.04) and to be discharged home (OR, 1.03).

“These findings support intensive efforts to accelerate hospital presentation and thrombolytic treatment in patients with stroke,” the researchers conclude.

Source: JAMA

Nidal embolization of brain arteriovenous malformations: rates of cure, partial embolization, and clinical outcome

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 Nidal embolization of brain arteriovenous malformations (bAVMs) has become an increasingly important component of bAVM treatment. However, controversy exists as to the relative efficacy and safety of single-stage versus multistage approaches to bAVM embolization, with recent literature favoring multistage strategies. The authors present a series of consecutive bAVMs embolized at their institution, demonstrating the safety and efficacy of a predominantly single-stage embolization strategy. The safety and efficacy of embolization are reported in the context of predetermined treatment strategies to provide more generalizable insight into treatment outcome.

Methods

One hundred thirty consecutive patients with 131 bAVMs underwent endovascular embolization at a single center. Diagnostic angiography with superselective microcatheterizations was performed in all patients. Postembolization angiograms were reviewed by 3 neuroradiologists for degree of occlusion and angiographic evidence of procedural complications. Patients were divided into cohorts based on the prospectively determined treatment strategy, which included the following: global devascularization of the bAVM (Devasc); targeting of a focal angioarchitectural weakness (Target), typically as an adjunct to surgery or Gamma Knife treatment; and primary occlusion of the bAVM by embolization alone (Occlude). Safety and efficacy were evaluated in the context of these treatment groups.

Results

The 131 bAVMs were treated over an average of 1.28 embolization sessions per bAVM; 105 bAVMs (80%) were treated in a single stage. The average percentage devascularization in the Devasc arm was 85.3%, which was statistically significantly greater than the 72% aggregate devascularization reported in 8 modern N-butyl cyanoacrylate and Onyx papers based on 1-sample Wilcoxon rank-sum testing (p < 0.001). Focal angioarchitectural weaknesses were successfully embolized for all 24 bAVMs in the Target group, directly with the embolic agent in 23 bAVMs and indirectly in 1 bAVM with a venous aneurysm/pseudoaneurysm by reducing arterial inflow and inducing venous thrombosis. Lesions in all patients in the Occlude arm were 100% occluded with embolization alone. Overall, the bAVMs in the Occlude arm were significantly smaller and required embolization of fewer pedicles than those in the Devasc group. One patient (0.8%) experienced significant morbidity following embolization, and 1 patient in the cohort died (0.8%).

Conclusions

This research communicates the authors’ experience in developing a largely single-stage strategy for embolization of bAVMs. The results suggest that an aggressive, single-stage embolization may be implemented with a margin of safety and effectiveness similar to the multistage approaches more commonly reported in the literature. This work additionally introduces the importance of prospective assignment to a treatment strategy in assessing procedural outcome in bAVM embolization, thereby improving generalizability of the results and allowing for more rigorous interpretation of efficacy and safety.

Source: Journal of Neurosurgery.