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Følgende dias er fremlagt ved DCS / DTS Fællesmøde 13. januar 2011 og alle rettigheder tilhører foredragsholderen. Gengivelse må kun foretages ved tilladelse

Antithrombotic therapy in Atrial Fibrillation

National treatment guideline

Steen Husted

Aarhus University Hospital

What is New in the 2010 Guideline? Impact on stroke prevention in DK?

Atrial Fibrillation (AF) is a common problem

• AF is the most common cardiac arythmia
• Very common in the elderly
• Related to co-morbidity
• MI
• Heart failure
• Hypertension
• Treatment of AF is a clinical challenge

The Management Cascade for patients with AF

European Heart Journal (2010) 31, 2369–2429

‘Natural’ time course of AF.

Camm A J et al. Eur Heart J 2010;eurheartj.ehq278

Decisions on Stroke Prevention in AF :

• Evidence based
• In accordance with guidelines
• Based on:
• Risk of stroke
• Risk reduction of stroke on antithrombotic treatment
• Risk of bleeding
• Contraindications to antithrombotic medications

Antithrombotics for stroke prevention in AF

• None
• Low risk
• Platelet inhibitor:
• Aspirin (ASA)
• Low risk
• Clopidogrel
• ASA intolerance
• ASA + Clopidogrel
• Contraindication for OAC
• OAC
• Vitamin K antagonists (VKA)
• Moderate to high risk
• New drugs
• Moderate to high risk
• Combinations
• ASA + VKA
• Common used in AF + IHD
• ASA + clopidogrel + VKA
• AF + Coronary artery stent/ACS
• Heparin ”bridging”
• Special conditions

Stroke Risk Estimation

• Clinical scoring systems:
• Low risk
• Intermediate risk
• High risk
• CHADS2
• CHA2DS2-VASc
• For refinement incorporate other risk factors:
• Age 65-74
• Female gender
• Vascular disease

Stroke risk stratification with CHADS2 and CHA2DS2-VASc scores

CHADS2 acronym Score CHA2DS2-VASc acronym Score Congestive heart failure 1 Congestive heart failure/LV dysfunction 1 Hypertension 1 Hypertension 1 Aged ≥75 years 1 Aged ≥75 years 2 Diabetes mellitus 1 Diabetes mellitus 1 Stroke/TIA/TE 2 Stroke/TIA/TE 2 Maximum score 6 Vascular disease (prior MI, PAD, or aortic plaque) 1 Aged 65-74 years 1 Sex category (i.e. female gender) 1 Maximum score 9

Stroke risk assessment with CHA2DS2-VASc

CHA2DS2-VASc criteria Score Congestive heart failure/ left ventricular dysfunction 1 Hypertension 1 Age 75 yrs 2 Diabetes mellitus 1 Stroke/transient ischaemic attack/TE 2 Vascular disease (prior myocardial infarction, peripheral artery disease or aortic plaque) 1 Age 65–74 yrs 1 Sex category (i.e. female gender) 1 CHA2DS2-VASc total score Rate of stroke/other TE (%/year) (95% CI)* (0–0) 1 0.6 (0.0–3.4) 2 1.6 (0.3–4.7) 3 3.9 (1.7–7.6) 4 1.9 (0.5–4.9) 5 3.2 (0.7–9.0) 6 3.6 (0.4–12.3) 7 8.0 (1.0–26.0) 8 11.1 (0.3–48.3) 9 100 (2.5–100)

*Theoretical rates without therapy corrected for the % of patients receiving Aspirin within each group, assuming 22% reduction in risk with Aspirin 13 Lip GYH et al. Chest 2010;137:263-72 TE = thromboembolism

Risk of Bleeding

• Risk of stroke and risk of bleeding is closely related
• OAC prescription needs to:
• Balance benefit from stroke prevention

and risk from bleeding

Risk factors for Bleeding

• Hypertension
• Abnormal renal/liver function
• Stroke
• Bleeding history or predisposition
• Labile INR
• Elderly (>65)
• Drugs/alcohol concomitantly

HAS-BLED new bleeding risk scoring system

• Hypertension
• Abnormal renal/liver function
• Stroke
• Bleeding history or predisposition
• Labile INR
• Elderly (>65)
• Drugs/alcohol concomitantly
• R. Pisters and GYHL. Lip et al.. Chest; Prepublished online March 18, 2010;

HAS-BLED bleeding risk score

Points Annual bleeding rate 0-1 <1.02 2 1.88 >3 >3.74 HAS-BLED score of ≥3, suggest caution and/or regular review

One approach - Benefits of VKA versus Risk of Bleeding

CHADS2 score Risk of Bleeding: ≥ 2

Outweighs the potential benefit of OAC if: HAS-BLED score > CHA2DS2 index.

1

NBV 2011

HAS-BLED score must exceed 2 for the potential harm caused by OAC use to offset its beneficial effect on stroke risk reduction

One approach - Benefits of VKA versus Risk of Bleeding

CHA2DS2-VASc-

score Risk of Bleeding: ≥ 2 Outweighs the potential benefit of OAC if: HAS-BLED score > CHA2DS2-VASc index. 1 HAS-BLED must be low 0-1, good quality VKA therapy with expected annual bleeding rate <2% or time in therapeutic interval more than 2/3 of time

• R. Pisters and GYHL Lip et al.. Chest; Prepublished online March 18, 2010;

Conclusion on VKA in AF

• Thromboprophylaxis in AF requires a beneficial balance

between stroke and bleeding risk

• Initially, consider CHADS2 score, or for more

comprehensive stroke risk assessment CHA2DS2-VASc score

• If score ≥2, OAC is clearly indicated
• For simple and easy bleeding risk assessment use:
• HAS-BLED score
• If score ≥3, clearly ‘at risk’ - caution

AF - Special situations

• Paroxysmal AF
• Perioperative anticoagulation
• Stable vascular disease
• Acute stroke
• Elective PCI
• ACS and/or PCI
• NSTEMI
• STEMI with primary PCI

Paroxysmal AF

• Stroke risk in paroxysmal AF
• Not different from that in persistent or permanent AF
• Patients with paroxysmal AF
• should receive OAC according to their risk score

Perioperative anticoagulation

• Many surgeons require:
• INR < 1.5 or even INR normalization before undertaking surgery
• What to do?
• Temporary interruption of VKA treatment before surgery or

an invasive procedure:

• Warfarin pause 4 days before procedure
• Phenprocoumon interrupted 7 days before procedure
• Pause for 48 h without bridging

PRAB report, www.DSTH.dk

Perioperative anticoagulation

• Mechanical heart valve or
• AF at high risk for thrombo-embolism (CHADS-score 4+)
• Bridging with therapeutic doses of
• LMWH

PRAP raport, www.DSTH.dk

Perioperative anticoagulation

• VKA resumed at the ‘usual’ maintenance dose:
• without a loading dose
• on the evening of surgery

PRAB raport, www.DSTH.dk

Stable vascular disease

• Many anticoagulated AF patients have
• stable coronary disease
• carotid artery disease and/or
• PAD
• Common practice:
• VKA + one antiplatelet drug
• usually ASA
• Adding ASA to VKA does not reduce the risk of
• stroke or
• vascular events (including MI)
• But substantially increases bleeding events !

Acute Stroke

• Acute stroke is a common first presentation AF
• Limited trial data to guide management
• Concern that patients within the first 2 weeks after

cardioembolic stroke have:

• greatest risk of recurrent stroke
• because of further thrombo-embolism
• Anticoagulation in the acute phase may result in
• intracranial haemorrhage or
• haemorrhagic transformation of a cerebral infarct

AF presenting with an acute stroke

• What to do:
• Treat uncontrolled hypertension
• before antithrombotic treatment is started,
• Cerebral imaging should be performed to exclude

haemorrhage

• CT
• MRI
• If no haemorrhage:
• anticoagulation should begin within 2 weeks –usually after 1-2 weeks
• If presence of haemorrhage
• anticoagulation should not be given

In AF presenting with acute TIA

• Anticoagulation treatment should begin as soon as

possible

• in the absence of cerebral infarction or haemorrhage

Acute coronary syndrome and/or PCI

• Current guidelines for ACS and/or PCI recommend
• ASA–clopidogrel combination therapy after:
• ACS and a stent
• 4 weeks for a bare-metal stent
• 6–12 months for a drug-eluting stent
• 12 months after ACS

ACS and/or PCI

• VKA non-treatment in high risk AF is associated with
• an increase in mortality and
• an increase major adverse cardiac events

Acute coronary syndrome and/or PCI

• The prevalence of major bleeding with triple therapy:
• VKA, ASA, and clopidogrel
• 2.6–4.6% at 30 days
• 7.4–10.3% at 12 months
• Acceptable risk–benefit ratio for 4 weeks
• if the bleeding risk is low

Antithrombotic strategies in coronary artery stenting in high risk AF

European Heart Journal (2010) 31, 2369–2429

How to chose the right OAC strategy in the future

• Important task for the Scientific societies

Thank you for your attention