Antiplatelet or Anticoagulant:Do They Have the same

Efficacy?

University of Central Florida

Deborah Andrews RN, BSN

• To evaluate antiplatelet versus anticoagulant agents for prevention of thromboembolic stroke in atrial fibrillation patients

• Anticoagulants: small therapeutic rangeUnderuse by health care providersNon-compliance by patients

Purpose

BackgroundAtrial Fibrillation

Disorganized contractions that disrupt

blood flow through the heart

2.66 Million Americans

2009 11,555 deaths attributed to AFib

Risk increases with age

6.4 Billion dollars annually in U.S.

Stroke

AFib increases risk by 5 fold

159,000 annually attributed to AFib

Ischemia is responsible for 87%

Strokes regardless of cause cost Americans

23 Billion dollars annually

24% of AFib patients not offered

pharmacologic treatment

Anticoagulant Agents

Warfarin reduces stroke by 60%

Inhibits Vitamin K clotting enzymes

Small therapeutic range

Multiple adverse effects

Only oral anticoagulant used in U.S.

Antiplatelet Agents

Aspirin: Up to 20% Stroke reduction

COX inhibitor

Readily available, Inexpensive,

Familiar

Adverse effects: GI, Bleeding, toxicity

New Antiplatelets: Clotting Cascade

Research Question

Do Antiplatelet Medications Have the

Same Efficacy as Anticoagulants for

Preventing Thromboembolic Events

in Atrial Fibrillation patients?

Relevance to Nursing

Management of Patient Medications1. Availability to Patients

2. Compliance

3. Less Adverse Risks

Quality of Life for Patients

Need for Education

Lower Healthcare Costs

MethodsData Bases:1. CINAHL Plus2. MEDLINE3. Cochrane Data Base of Systemic

Reviews

GoogleSearch Terms: Anticoagulant, Antiplatelet Atrial Fibrillation, Stroke Prevention, Warfarin, Aspirin, Clopidogrel

Definitions

Criteria

Inclusion

• Published: 2000 - 2010

• AFib Patients >60 years

• Available in English

• Measurable Outcomes

• Prevention of

Thromboembolic Events

• Oral agents

• Randomized

Exclusion

• Duplicate Studies

• Published prior to 2000

• Embolic events From

Other Sources

• Intravenous agents

• Patients < 60 years

• Poor Quality

Methods

Findings

1 Meta-Analysis: 29 trials = 28,044 Pts (Level 1)

2 Random Control Trials: (Level 2)973 & 574 Pts

United States, United Kingdom, & Spain(Global studies)

Randomization

Intention to Treat

Adjusted Dose Warfarin

Aspirin or Other Antiplatelet

Ischemic Stroke, All Stroke, Other Thromboembolic events

Study Characteristics

Sample Characteristics

Atrial Fibrillation Patients

Age: > 60 & < 85

With or Without Prior Stroke

Average follow up: 1.5 – 4.92 yrs.

Women: 45%

Randomized to either Warfarin or Antiplatelet agent

Themes

Validity of Findings12 Point Screening of RCTs

Intent Clearly Stated

Design Appropriate for Research Question

Appropriate Inclusion and Exclusion Criteria

Evidence Calculations extrapolated from Sample Size

Biases Averted

Proper Descriptions of Interventions and Controls

Outcomes Are Relevant Clinically

Similarities Between Groups were Similar

All With Intention to Treat

Studies Align with Previous Studies

Participants Equivalent to Current Patients

Findings Support Practice Change

Synopsis of Finding

Synopsis of Findings

Hart et al., 2007 & Mant et al., 2007

Synopsis FindingsOAC

Bover et al., 2009 & Hart et al. 2007

Total of All Trials, 29,457 Patients 4.8% Stroke Rate

Bover et al., 2009, Hart et al. ,2007, & Mant et al., 2007

Time in Therapeutic Range

INR Ranges Varied Study to Study

Average Time in Therapeutic Range

67% - 69%

(Meta-Analysis: undetermined)

Bover et al., 2009, Hart et al. ,2007, & Mant et al., 2007

Recommendations for Nursing

Prospective Queries

Is Combination Therapy Better Than Monotherapy for Prevention of Ischemic Stroke?Are the New Antiplatelet Agents Safer Than Warfarin?