Clinical audit: Antiplatelet and anticoagulant therapy in stroke ...

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Clinical audit: Antiplatelet and anticoagulant therapy in stroke prevention
Improving clinical practice for better patient health
How are you managing your patients?
This clinical audit activity has been
approved by the RACGP QA&CPD Program,
total points: 40 (Category 1) in the
This clinical audit will assist you to assess and select appropriate evidence-based
2008–2010 triennium and by the ACRRM
drug therapies for stroke prevention and to optimise their use.
PD Program for 30 points (extended skills).
Points are awarded only to participants
Identify 15 patients with:
who complete the review phase.
• paroxysmal, persistent or permanent atrial fibrillation (AF) or atrial flutter and/or
This audit is recognised for the
• a previous ischaemic stroke or transient ischaemic attack (TIA) and/or
Quality Prescribing Initiative of the
Practice Incentives Program
• oral antiplatelet and/or anticoagulant therapy prescribed for primary or secondary
(May 2009 to April 2010).
prevention of stroke.
Best practice use of antiplatelets and anticoagulants in stroke prevention
1. Use best practice
Stratify stroke risk in patients with
“ Do I routinely assess the risk of stroke
non-valvular AF
in patients with non-valvular AF using a
Stroke risk informs the choice between
risk stratification tool e.g. CHADS ?”
warfarin or aspirin in non-valvular AF.
Assess bleeding risk in patients being “ Do I review risk factors for bleeding
considered for anticoagulant therapy
before starting anticoagulant therapy?”
2. Review current
5. Monitor progress
Reassess regularly in patients using
“ Do I periodically review risk factors for
anticoagulant therapy
Select appropriate anticoagulant or
“ Are my patients with AF at moderate
antiplatelet therapy based on stroke
to high risk of stroke, using warfarin?”
risk and bleeding risk
“ Are my patients with AF at low risk
Use warfarin or aspirin in patients with AF,
of stroke or with contraindications to
depending on risk of stroke and bleeding.
warfarin, using aspirin?”
Aspirin, aspirin plus dypridamole SR, or
“ Are my patients with previous ischaemic
clopidogrel are options for long-term
stroke or TIA due to arterial disease using
antiplatelet therapy in patients with previous
aspirin, aspirin plus dipyridamole SR, or
ischaemic stroke or TIA due to arterial disease.
Monitor and follow up INR regularly
“ Have I set up a system to ensure
Once stabilised, INR should be monitored at
appropriate INR monitoring and patient
least every 4 weeks.
follow up?”
Target INR is 2−3 for all indications (except “ Do I review use of drugs that may affect
prosthetic heart valves).
INR or increase the risk of bleeding with
“ Are INRs maintained in the target range?”
4. Review and reflect
Enhance patient skills in self-
“ Do I assess adherence to drug therapy?
3. Implement change
management of warfarin and
“ Do I provide patients with printed
adherence to antithrombotic therapy
information on antiplatelets or
Provide patients with medicine instructions;
this is associated with a lower rate of warfarin-
related hospitalisation for bleeding.

Notes for clinical audit
Additional information to assist you to review your management.
Identify 15 patients prospectively as they present or retrospectively from a
search of your medical records.

Include patients who have:
Exclude patients with:
• paroxysmal, persistent or permanent AF (valvular
• lone AF (< 60 years of age with
and non-valvular) or atrial flutter and/or
no hypertension and no clinical or
• a previous ischaemic stroke or TIA and/or
echocardiographic evidence of heart disease)
• oral antiplatelet and/or anticoagulant therapy
• previous haemorrhagic stroke
prescribed for primary or secondary prevention
• prosthetic heart valves.
of stroke.
Management of other risk factors for stroke including hypertension, obesity, smoking, vascular disease
and diabetes is not addressed in this audit. Assessing and managing these risk factors is an essential part
of reducing stroke risk. Use of thrombolytic therapy in acute stroke is also not addressed.
About 85% of all strokes are ischaemic, of which 20% are due to embolism of thrombi from the heart
Prevention of cardioembolic ischaemic stroke
Patients with atrial fibrillation (AF) have a three- to five-fold
Table 1: Classification of atrial fibrillation
higher risk of ischaemic stroke than those without AF.2
Warfarin is underused in patients with AF at high risk of
Absolute stroke
stroke and with no contraindications to its use.3 Use of
risk per annum
warfarin is especially low in patients with AF of non-English
Valvular AF
15% to 20%1
speaking background.3 The main reason cited is concern
Very high risk
(stroke risk stratification
about potential bleeding but there is evidence that the risk
not required)
of bleeding with warfarin may be overemphasised.2
2% to 18%5
warfarin or aspirin
In patients with AF absolute stroke and bleeding risks inform
the choice between warfarin and aspirin.4 Paroxysmal,
depending on risk (depending on stroke risk,
persistent and permanent AF all pose the same stroke
factors (see table 4)
see table 4)
risk.1,2 Patients with valvular AF are at particularly high risk
of stroke and do not require risk stratification (see Table 1).
similar stratification criteria as for AF (see below).1 Stroke risk
in these patients is estimated to be higher than for those in
In patients with atrial flutter, assess the risk of stroke using
sinus rhythm and less than for persistent or permanent AF.4
Determining stroke risk in patients with non-valvular AF
Patients with valvular AF are at very high risk and do not require stratification.
In patients with non-valvular AF, use a risk stratification tool to assess stroke risk and choose between warfarin and aspirin.
The CHADS stratification tool is validated and based on two other stratification tools, but with a greater predictability
than either of these tools alone.5 Points are assigned based on the presence of various risk factors. The total score gives an
indication of the degree of stroke risk (see Tables 3 and 4).
Table 3: Components of CHADS and point scoring5,6
Table 4: CHADS score and risk of stroke
Relative risk of CHADS
CHADS % Adjusted annual
Stroke Recommended
Prognostic risk factors
Score stroke Rate (95% CI)5
Congestive heart failure
1.9% (1.2 to 3.0)
Hypertension (past or present)
2.8% (2.0 to 3.8)
aspirin or warfarin
Age ≥ 75 years
4.0% (3.1 to 5.1)
5.9% (4.6 to 7.3)
Stroke or TIA previously
8.5% (6.3 to 11.1)
12.5% (8.2 to 17.5)
18.2% (10.5 to 27.4)

Determining bleeding risk in patients considered for anticoagulant therapy
Assess risk factors for bleeding in all patients being considered for anticoagulant therapy.2 Reassess risk factors periodically.2
Table 5: Assessing risk factors for bleeding2,8,9
Absolute contraindication regarding warfarin use*
bacterial endocarditis
previous intracranial bleed/aneurysm or retinal haemorrhage
bleeding disorders
recent gastrointestinal/genitourinary bleeding or active ulceration
frequent falls
unsupervised dementia
non-adherence with medication or INR monitoring
untreated or poorly controlled hypertension
(consistently > 160/90 mmHg)
Relative contraindication
conventional NSAID use without cytoprotection
participation in activities predisposing to trauma
heavy alcohol use or liver disease
unexplained anaemia
unexplained recurrent syncope
No contraindication
advanced age
predisposition to falling
COX-2 selective NSAID use
previous ischaemic stroke
NSAID use with misoprostol or proton pump inhibitor
recent, resolved peptic ulcer disease bleeding (with H. pylori testing
and treatment)
* Other contraindications to warfarin use may include: recent or contemplated CNS, eye or traumatic surgery; major regional
lumbar block anaesthesia; pregnancy.
Anticoagulant (warfarin or phenindione) therapy
Consider warfarin for all patients with valvular AF and those with non-valvular AF at moderate to high risk of stroke
(CHADS score ≥ 1).4,7 Consider in those with previous myocardial infarction (MI) at increased embolic risk (e.g. left ventricular
thrombi detected within 3–6 months of MI).8 (See Drug evidence and recommendations insert.)
Monitoring INR
Frequency of INR monitoring:
• Initially: before starting warfarin and then daily until INR is stable in the therapeutic range.
• Long term: regular intervals of no more than 4 weeks.
• More frequently if there are changes to the patient’s condition including intercurrent illness (e.g. heart failure, liver
disease, GI disturbances, infections, thyroid disorders), concurrent drugs, amount of alcohol consumed, or diet (green leafy
vegetable consumption).8
Target INR is 2–3 for all indications except prosthetic heart valves (seek specialist advice).8 Almost half of all haemorrhages
occur when INRs are above the therapeutic range and about half of thromboemboli occur when below it.10 There is
insufficient evidence to recommend a compromise INR (e.g. 1.6 to 2.5) in subgroups of patients with AF; efficacy is around
80% of that achieved with higher anticoagulation.2,4
Reviewing use of drugs/complementary medicines with potential interactions with warfarin
Identify and where possible exclude drugs which interact with warfarin (see Table 6).2 Alternatively, allow for the effects on
warfarin control.2

Table 6: Commonly used drugs and complementary medicines which potentially affect INR control8,11,12
Increased effect of warfarin (INR)

COX-2 selective NSAIDs (celecoxib)
selective serotonin re-uptake inhibitors
anabolic steroids and androgens
statins e.g. fluvastatin, rosuvastatin,
e.g. testosterone
simvastatin (consider using atorvastatin
antibiotics – cotrimoxazole, macrolides,
or pravastatin)
metronidazole, quinolones (ciprofloxacin,
moxifloxacin), tetracyclines
thyroid and antithyroid compounds
paracetamol (> 3.5 g weekly) – check
azole antifungals (fluconazole, itraconazole,
e.g. thyroxine, propylthiouracil
INR 4 days after starting paracetamol
quinine and quinidine
salicylates (topical) e.g. methysalicylate
Complementary medicines or foods
cranberry juice
dong quai
Decreased effect of warfarin (INR)

antibiotics – dicloxacillin, rifabutin, rifampicin cholestyramine
antiepileptics (barbiturates, carbamazepine, griseofulvin
Complementary medicines or foods
coenzyme Q10
St John’s wort
fermented soya bean products
green tea
Increased or decreased effect of warfarin ( or INR)

Potentiated bleeding risk with warfarin due to their antiplatelet effect
aspirin – avoid combination
NSAIDs (except COX-2 selective inhibitors)
(except low-dose aspirin in selected
patients at high risk for thromboembolism
where close monitoring is required)
Aspirin, other NSAIDs and gingko biloba also potentiate the bleeding risk because of their effects on the gastric mucosa.12
Food interactions with warfarin
Most people taking warfarin do not experience any problems related to the amount of vitamin K in their diet.2 Advise patients
to maintain a relatively constant intake of vitamin K-containing foods. Provide patients with a list of such foods (see Patient
information on warfarin
Enhancing patient understanding of warfarin
Give all patients on medication for stroke prevention verbal and written information about their medicines in a format appropriate
to their needs and abilities.13

Cardioembolic ischaemic stroke, continued
Patient information on warfarin
Important advice for patients using warfarin8
Repatriation General Hospital (RGH) Pharmacy,
SA: Anticoagulation handbook.
• Take tablets at the same time every day; use a calendar or
‘anticoagulant book’ to keep a record of your dose and to
Sigma Pharmaceuticals: Dietary guidelines and drug–herb
mark off the date immediately after taking a dose.
interactions for people taking warfarin (go to:
• Always use the same brand of tablets.
• Eat a balanced diet, without varying it too much, to keep
Sigma Pharmaceuticals: Important instructions for patients –
warfarin (go to:
vitamin K intake stable; warfarin is affected by vitamin K,
which is found in some foods.
WA Medication Safety Group (WAMSG) Anticoagulant
• Avoid excessive alcohol consumption, 1–2 standard
Working Group: Living with warfarin – information for
patients (go to:
drinks/day is generally safe.
• Avoid drinking large amounts of cranberry juice; this may
Antiplatelet therapy
increase the effects of warfarin.
Use aspirin in patients with non-valvular AF at low risk of
• Tell your doctor or pharmacist that you are taking
stroke or where warfarin is contraindicated (see table 4 and
warfarin before starting or stopping other drugs, vitamin
Drug therapy evidence and recommendations insert).
supplements, complementary or over-the-counter
Aspirin intolerance
• Tell your dentist, podiatrist, physiotherapist or chiropractor
Confirm that patients have true intolerance to aspirin.
that you are taking warfarin.
Aspirin intolerance is defined as:
• Have regular blood tests, call for a result within 24 hours
• proven hypersensitivity to aspirin-containing medicines
of the test and before the next dose in case it needs
• history of severe dyspepsia induced by low-dose aspirin.14
adjusting. Extra tests may be needed when you are
Hypersensitivity includes aspirin-exacerbated respiratory
experiencing any other serious illness.
tract disease, urticaria/angioedema, or anaphylaxis.
• Tell your doctor immediately if you have any unexplained
bruising, bleeding, pink, red or dark brown urine, or black
The prevalence of aspirin-exacerbated respiratory tract
disease is approximately 10% and for aspirin-induced
or red faeces.
urticaria the prevalence varies from 0.07% to 0.2% in the
general population.15
Adding a proton pump inhibitor to aspirin
Only consider adding a proton pump inhibitor (PPI) to
aspirin if there is dyspepsia, or other significant risk of
gastrointestinal bleeding with aspirin, to allow aspirin to
continue.13 In patients with a history of aspirin-induced
ulcer bleeding, clopidogrel causes more recurrent ulcer
bleeding than aspirin plus a PPI.8
Prevention of ischaemic stroke due to arterial disease
Antiplatelet therapy
In primary stroke prevention, consider aspirin for those at
In patients with a previous ischaemic stroke or TIA
high risk of cardiovascular disease.8 Vascular benefits of
due to arterial disease, long-term antiplatelet therapy
aspirin are most likely to outweigh the bleeding risk if the
is recommended; there is no evidence of additional
5-year absolute risk of a cardiovascular event is > 15%.16
benefit with anticoagulation in these patients.17 Aspirin,
(see Drug therapy evidence and recommendations insert.)
aspirin plus dipyridamole SR or clopidogrel are the main
antiplatelet options.17 (see Drug therapy evidence and
recommendations insert.)
Table 7: Contraindications to antiplatelet use8,9
Active peptic ulceration, allergy to aspirin/NSAIDs, aspirin-sensitive asthma, bleeding disorders
Severe hepatic impairment, active internal bleeding, pregnancy, lactation
Hypersensitivity to any component
Bleeding disorders, local haemorrhagic legions (e.g. peptic ulcer, epistaxis, menorrhagia, haemorrhagic
stroke), blood dyscrasias, severe hepatic impairment or cholestatic jaundice.

Confidentiality and privacy
You must sign and date the Submission cover sheet to
What will happen to your personal details
participate in this audit. By participating you agree to
aggregation of your de-identified patient data and use
Your personal details:
of your personal data. Individual results of your clinical
• are provided to the mail house for processing
audit are kept confidential by NPS.
• are provided to the RACGP QA&CPD Program
and/or ACRRM Professional Development Program
What will happen to your patient data
for point allocation (if applicable)
• Your de-identified patient data forms are scanned
• are recorded for the purpose of the PIP
and returned to you.
and NPS evaluation
• Your individual results are provided to you only.
• can be obtained from NPS by request in writing.
• Your data are aggregated with those of other
Individual clinical audit results wil not be available
participants and the de-identified aggregate results:
after potential y identifying data are removed from
NPS records at the close of the clinical audit cycle.
– are provided to all participants
– may be used in NPS evaluation and reports
Please note: You are responsible for advising NPS
of any changes of address during the audit cycle.
– are provided to the RACGP and ACRRM.
The RACGP has advised that program information
Further information
may be shared with researchers and interested general
practitioners for the purpose of continuing education
Therapeutic enquiries
coordination at the discretion of the QA&CPD Program.
Karin Gurman
(02) 8217 8700
Audit and QPI enquiries
Chun Fang Yu
(02) 8217 8700
1. Neurology Expert Group. Therapeutic Guidelines:
8. eAMH [online]. 2008.
16. New Zealand Guidelines Group. The assessment
Neurology, Version 3. eTG complete. 2007.
9. MIMS online. 2009.
and management of cardiovascular risk. New
2. New Zealand Guidelines Group. The management
10. Oake N, et al. CMAJ 2007;176:1589–94.
Zealand. Wel ington: New Zealand Guidelines
of people with atrial fibril ation and flutter.
Group, 2003.
11. Stockley’s drug interactions 8th ed. London:
Evidence-based best practice guideline.
gl_complete/CVD_Risk/Ful _text_Guideline.pdf
The Pharmaceutical Press, 2008.
Wel ington: New Zealand Guidelines Group, 2005.
(accessed 23 September 2008).
12. Campbell P, et al. Aust Prescriber 2001;24:86–9.
17. National Stroke Foundation. Clinical guidelines
Guide_(final).pdf (accessed 9 September 2008).
13. Intercol egiate Stroke Working Party. National
for stroke and TIA management. A guide for
clinical guideline for stroke 3rd ed. London: Royal
3. National Institute of Clinical Studies. Evidence-
general practice. Melbourne: National Stroke
College of Physicians, 2008. http://www.rcplondon.
practice gaps report. Volume 1:A review of
Foundation, 2008: http://www.strokefoundation.
developments 2004-2007. Melbourne: National,com_docman/
9772d1d5301b.pdf (accessed 23 September 2008).
Institute of Clinical Studies, 2008.
14. National Institute for Health and Clinical Excel ence.
(accessed 8 September 2008).
resources/evidence_volume_one.htm (accessed 9
Clopidogrel and modified-release dipyridamole
September 2008)
in the prevention of occlusive vascular events.
Technology appraisal guidance 90. London:
4. Fuster V, et al. Circulation 2006;114:e257–e354.
National Institute for Health and Clinical Excel ence,
5. Gage BF, et al. JAMA 2001;285:2864–70.
6. Medi C, et al. Med J Aust 2007;186:197–202.
TA090guidance.pdf (accessed 8 September 2008).
7. Gage BF, et al. Circulation 2004;110:2287–92.
15. Gollapudi RR, et al. JAMA 2004;292:3017–23.
March 2009
The information contained in this material is derived from a critical analysis of a wide range of authoritative evidence.
Any treatment decisions based on this information should be made in the context of the clinical circumstances of each patient.
National Prescribing Service Limited ACN 082 034 393
An independent, non-profit organisation for Quality Use of Medicines,
funded by the Australian Government Department of Health and Ageing.
Level 7 / 418A Elizabeth Street Surry Hills NSW 2010
Phone: 02 8217 8700 l Fax: 02 9211 7578 l email: [email protected] l web:

Drug therapy evidence and recommendations
Prevention of ischaemic stroke due to arterial disease (atherothromboembolism)
Drug therapy
Primary prevention
Secondary prevention
Balance potential benefits in terms of overall
Reduces the relative risk of stroke by about 13% (95% CI 6% to 19%) compared with placebo.3 Risk is further reduced by the addition
Astrix 100, Astrix tablet, Cardiprin 100,
cardiovascular protection, against the risk of major
of dipyridamole (see below).
Cartia, Disprin, Solprin
Give as soon as possible after the onset of stroke. Can also be used for long-term antiplatelet therapy after stroke or TIA.1
Vascular benefits of aspirin are most likely to
Suitable option for patients who:
outweigh the bleeding risk if the 5-year absolute risk • cannot tolerate dipyridamole
of a cardiovascular event is > 15%.2 Assess absolute • have co-existing coronary heart disease
cardiovascular risk using a standardised tool.*
• for whom cost considerations are paramount.4,5
aspirin plus dipyridamole SR
Not indicated; no evidence that combining aspirin
Adding dipyridamole to aspirin reduces the risk of the composite endpoint of MI, stroke, vascular death or major bleeding complication
Asasantin SR
and dipyridamole is significantly more effective than compared with aspirin alone (ARR = 1% per year, 95% CI 0.1 to 1.8).6
low-dose aspirin.1
Can be used for initial long-term antiplatelet therapy or if recurrent stroke occurs while taking aspirin.1
Use sustained-release preparations; immediate-release preparations have limited evidence to support their use in stroke.7
Headache is common with dipyridamole and leads to more discontinuation of therapy than with aspirin alone.8 Substituting the morning
dose of aspirin plus dipyridamole SR with low-dose aspirin for a short period (e.g. < 1 week) may improve headache.9
Not indicated 9
Slightly more effective than aspirin alone in reducing combined endpoint of ischaemic stroke, MI or vascular death (absolute risk
Iscover, Plavix
reduction [ARR] = 0.51%) in patients with atherosclerotic vascular disease; need to treat 196 patients with clopidogrel instead of aspirin
for 1 year to prevent one vascular event.10 Similar overall risk of bleeding to aspirin, but less cost effective.1,10,11
Similar efficacy to aspirin plus dipyridamole SR in prevention of recurrent stroke and comparable risk of bleeding.8
Can be used for initial long-term antiplatelet therapy and is a suitable alternative to aspirin for patients with:
• intolerance or contraindication to aspirin1,4
• recurrent vascular events while on aspirin.1
Suitable alternative to aspirin plus dipyridamole SR for patients with:
• intolerance to aspirin plus dipyridamole4
• co-existing coronary heart disease5, for which aspirin plus dipyridamole has less evidence.
Better tolerated than ticlopidine (see below).12
dipyridamole SR
Not indicated 9
No evidence that dipyridamole alone is more effective than aspirin alone.13
Persantin SR
Use in combination with aspirin (see above).
Use alone if neither aspirin nor clopidogrel is tolerated.4
Not indicated 9
Severe haematological adverse effects limit its use; can cause mild–severe neutropenia, risk is greatest in first 12 weeks of treatment.12
Use in patients unresponsive to aspirin.12 Where possible, use clopidogrel instead of ticlopidine due to lower risk of severe adverse effects.12
aspirin plus clopidogrel
Not indicated
Not recommended for patients with a recent TIA or stroke12; combination is no more effective than aspirin or clopidogrel alone for
secondary prevention of ischaemic stroke but increases the risk of moderate or life-threatening bleeding.14-16
Combination is indicated in patients with an acute coronary syndrome or coronary stent.12
* Use the National Vascular Disease Prevention Alliance (NVDPA) paper-based tool or online calculator, or until these are available, the New Zealand Guidelines Group Cardiovascular Risk Calculator (at

Prevention of cardioembolic ischaemic stroke
Primary prevention
Secondary prevention
Reduces relative risk of stroke by about 60% to 70% in patients with atrial fibrillation (AF) compared to no treatment.1,12 More effective than aspirin in reducing the risk of stroke due to
Coumadin, Marevan
AF but is more likely to cause major bleeding.17
Use in all patients with valvular AF, unless contraindicated.17
Use in all people with previous cardioembolic ischaemic stroke e.g. due to AF, valvular heart disease or recent MI,
Consider use in patients with non-valvular AF at moderate to high risk
unless contraindicated.4 Patients with a previous thromboembolic event are at high risk of stroke.1
of stroke (CHADS score ≥ 1) unless contraindicated.1,4,18 Use a risk
Start anticoagulation after cerebrovascular events only after brain imaging has excluded haemorrhage and
stratification tool e.g. CHADS to determine stroke risk in non-valvular
not usually until 14 days have passed from the onset of disabling ischaemic stroke.19
AF (See Guide p.3). Warfarin or aspirin can be used in patients with a
CHADS score = 1.
Consider use in those with previous myocardial infarction (MI) at increased
embolic risk (e.g. left ventricular thrombi detected within 3–6 months of MI).12
Less effective than warfarin in patients with AF; reduces the relative risk of stroke by about 20%, but less likely to cause severe haemorrhage.12
Astrix 100, Astrix tablet, Cardiprin 100,
Use in patients with non-valvular AF at low risk of stroke (e.g. CHADS
Use in patients with AF if anticoagulation is contraindicated.1,17
Cartia, Disprin, Solprin
score = 0) or when anticoagulation is contraindicated.18
An option for patients with CHADS score = 1.18
clopidogrel Iscover, Plavix
Currently no evidence to support use over aspirin or warfarin in patients with AF.1
phenindione Dindevan
Indications as for warfarin (see above). Much less widely used than warfarin due to higher incidence of adverse effects especial y al ergic reactions e.g. liver and kidney damage, rash,
myocarditis, blood dyscrasia.12
aspirin plus clopidogrel
Not recommended in patients with AF; warfarin is safer and more effective.12
Indications for other drug therapy combinations
aspirin, clopidogrel plus warfarin May be indicated in patients with an acute coronary syndrome or coronary stent and using warfarin therapy for another indication.20 Seek specialist advice.
aspirin plus warfarin
Aspirin plus low-dose warfarin is not as effective as adjusted-dose warfarin alone for stroke prevention in patients with AF.17
Adding aspirin to adjusted-dose warfarin does not provide further reductions in stroke risk in patients with AF.17
Adding aspirin for another indication (e.g. coronary artery disease) may benefit people with AF using warfarin for thromboembolic prophylaxis, but the risk of bleeding increases.12,17
Dose of aspirin should probably be 75–100 mg/day.17
Combination indicated in recurrent thrombosis or mechanical valve prosthesis.17
dipyridamole plus warfarin
Used for prevention of thromboembolism in patients with prosthetic heart valves.12
1. Neurology Expert Group. Therapeutic Guidelines: Neurology. eTG complete 2007;Version 3
8. Sacco R, et al. N Engl J Med 2008;359:1238–51.
17. New Zealand Guidelines Group. The management of people with atrial fibril ation and
2. New Zealand Guidelines Group. The assessment and management of cardiovascular risk.
9. MIMS online. 2009 (accessed 2 December 2008).
flutter. Evidence-based best practice guideline 2005. Wel ington: New Zealand Guidelines
New Zealand, 2003.
10. CAPRIE Steering Committee. Lancet 1996;348:1329–39.
Group, 2005.
Guideline.pdf (accessed 23 September 2008).
11. Hankey GJ, et al. Cochrane Database Syst Rev 2000;(1):CD001246.
18. Fuster V, et al. Circulation 2006;114:e257–e354.
3. Algra A, Van Gijn J. J Neurol Neurosurg Psychiatry 1999;66:255.
12. eAMH [online]. 2008.
19. Intercol egiate Stroke Working Party. National clinical guideline for stroke, 3rd edition.
4. National Stroke Foundation. Clinical Guidelines for Stroke and TIA Management. A guide
London: Royal College of Physicians, 2008.
13. De Schryver E, et al. Cochrane Database Syst Rev 2007;(3):CD001820.
for general practice. 2008. Full guideline:
20. Orford JL, et al. Am Heart J 2004;147:463–7.
14. Diener H-C, et al. Lancet 2004;364:331–7.
option,com_docman/Itemid,174/task,doc_view/gid,149/(accessed 8 September 2008).
15. Bhatt DL, et al. N Engl J Med 2006;354:1706–17.
5. Donnan GA, et al. Lancet;371:1612–23.
16. Scottish Intercol egiate Guidelines Network. Management of patients with stroke or TIA:
6. Halkes PHA, et al. Lancet 2006;367:1665–73.
assessment, investigation, immediate management and secondary prevention – A national
7. Verro P, et al. Stroke 2008;39:1358–63.
clinical guideline. Edinburgh: Scottish Intercollegiate Guidelines Network; 2008.
March 2009 NPSA0873

Antiplatelet and anticoagulant therapy
in stroke prevention 2009
Your patient code: Do not use patient name.
Use this to identify your patients for the Review Phase.
NPS office use only
Use a black biro to mark a cross (X) in the box
beside your response. If you make a mistake, use
white correction fluid.
Patient details
Is the patient of non-English speaking background?
not known
Medical history
Diagnosis: Mark ALL that apply
NOTE: Exclude patients with prosthetic heart valves, haemorrhagic stroke or lone AF.
atrial fibrillation (AF)
atrial flutter
previous stroke or TIA
other reason for stroke prevention (specify) _______________________
If you answered atrial fibrillation, what type:
valvular AF
non-valvular AF
not known (see Guide p.2)
not known
If you answered previous stroke or TIA:
Was the patient on aspirin prior to the stroke/TIA?
not known
Type of stroke:
cardioembolic (e.g. due to AF, recent MI or valvular heart disease)
due to arterial disease
not known
Other relevant coexisting conditions/procedures: Mark ALL that apply
coronary stent (< 1 year ago)
mural thrombus
recurrent venous thrombosis
coronary artery disease
previous myocardial infarction
previous venous thromboembolism
other _____________________
acute coronary syndrome
Stroke risk assessment
Bleeding risk assessment – complete for patients considered for
or using warfarin
Does the patient have the following risk factors for stroke?
Does the patient have any contraindications to warfarin use?
Congestive heart failure
no contraindications
not known
Absolute contraindications Mark ALL that apply
+ Hypertension (current or past)
bacterial endocarditis
bleeding disorder
frequent falls
not known
non-adherence with medication or INR monitoring
+ Age
previous intracranial bleed/aneurysm or retinal haemorrhage
85 years
75–84 years
60–74 years
< 60 years
recent gastrointestinal/genitourinary bleeding or active ulceration
+ Diabetes mellitus
unsupervised dementia
not known
untreated or poorly controlled hypertension
(consistently > 160/90 mmHg)
+ Stroke or TIA previously
Relative contraindications Mark ALL that apply
not known
conventional NSAID use without cytoprotection
heavy alcohol use or liver disease
If non-valvular AF or atrial flutter, calculate CHADS2 score
participation in activities predisposing to trauma
= CHADS2 score
unexplained anaemia
unexplained recurrent syncope
Consider warfarin if CHADS2 score ≥ 1 (see Guide p.2)
other (specify) ________________________________________
Current pharmacological management
Anticoagulant therapy

Is an oral anticoagulant (warfarin or phenindione) currently used?
10. What is the patient’s target INR range?
< 1.5
Go to Q10
contraindication (see Q8 and Guide p.3)
adverse effect
not indicated
not previously considered
> 3.5
no access to INR monitoring
other (specify) ________________________________________
patient refusal
What was the patient’s last INR result?
other (specify) ____________________________________________________
Is this INR result:
Go to Q11 (see over)
below target range
in target range
above target range
Please turn over to complete form

10. (continued)
12. Current antiplatelet drug(s) used: Mark ALL that apply
If the INR is not in target range, is it due to:
Aspirin (including combination products)
anticoagulant newly started/restarted
intercurrent illness
history of severe dyspepsia with low-dose aspirin
medication change (incl. complementary)
proven hypersensitivity to aspirin or NSAID
significant diet change
(induced asthma, urticaria or anaphylaxis)
dosage change
other contraindication (see Guide p.5)
poor adherence
co-existing condition seen as precaution e.g. asthma,
history of peptic ulcer
other (specify) ________________________________________
adverse effect
not indicated
What is the current frequency of INR monitoring?
not previously considered
daily to < weekly
weekly to < fortnightly
other (specify) ____________________________________________________
fortnightly to ≤ 4 weekly
5 to 6 weekly
> 6 weekly
Dipyridamole (including combination products)
INR monitoring is undertaken in: Mark ALL that apply
GP practice
patient’s home
Does the patient keep a record of INR results and warfarin doses?
adverse effect
not known
not indicated
Have you confirmed patient contact details are up to date for
not previously considered
INR follow up?
other (specify) ____________________________________________________
not known
The patient is concurrently using drug(s)/complementary
medicine(s) which may: Mark ALL that apply (see Table 6, Guide p.4)
increase INR
decrease INR
increase or decrease INR
increase the risk of bleeding due to its antiplatelet effect
not on an interacting drug/complementary medicine
Antiplatelet therapy
(specify) ______________________________________________________________________________________
11. Is an oral antiplatelet currently used?
Are any of the following co-prescribed?
proton pump inhibitor
Go to Q12
contraindication to all antiplatelets
H2 receptor antagonist
adverse effect with all antiplatelets
If any are co-prescribed, does the patient have: Mark ALL that apply
not indicated
not previously considered
aspirin-induced dyspepsia
using warfarin
high risk of GI bleeding with antiplatelet
other (specify) _________________________
gastro-oesophageal reflux disease or peptic ulcer disease
Go to Q13
other (specify)_____________________________________________________________________________
Patient support and follow up
13. Which of the following have been provided? Mark ALL that apply
16. Which, if any, of the following actions do you plan to undertake
consumer medicine information (CMI)
for this patient? Mark ALL that apply
written information on
none (no action planned at this stage)
Assessment and monitoring
other (specify) ______________________________________
reassess bleeding risk regularly
monitor INR more frequently
14. Has the patient had any of the following in the last 12 months?
Drug therapy
Mark ALL that apply
initiate anticoagulant therapy
initiate antiplatelet agent
home medicines review (HMR)
cease anticoagulant therapy
cease antiplatelet agent
team care arrangement
review use of drugs which may affect INR
GP management plan
Follow up
none of the above
refer to neurologist/cardiologist
15. If the patient is using an anticoagulant and has had an HMR,
refer for HMR
was this undertaken since the anticoagulant was started?
initiate team care arrangement
initiate GP management plan
provide CMI
not known
provide written information on
HMR not undertaken
not using an anticoagulant
other (specify)_____________________________________________________________________________
Document any planned actions in the ‘Action plan for individual patients’ and/or the patient’s file to assist with implementing changes to practice.