stroke secondary prevention guidelines; aspirin afib

update on 2011 guidelines on stroke prevention in patients with prior stroke or TIA (see stroke secondary prevention guidelines stroke 2014 in dropbox, or DOI: 10.1161/STR.0000000000000024)

background: stroke still very prevalent. 700K adults with ischemic stroke/yr in the US. addl 240K with TIA (with residual high risk of subsequent stroke, 3-4%/yr, similar to having had initial ischemic stroke. rate is lower than before because of widespread use of antiplatelet drugs, treatment for hypertension, afib, hyperlipidemia, arterial obstruction).

changes from 2011 (there are lots of them, and these are just the changes):

    --hypertension.    

            --initiate therapy if systolic >140, or diastolic >90. no clear evidence that one class of drug is superior [though prior studies sent out before have found increased stroke in meds with higher bp variability,                 with amlodipine having the least]. uncertain benefit if initial blood pressure lower than that

            --goal bp is 140/90. "might be reasonable goal" of systolic 130, if lacunar stroke

            --if pt has stroke/TIA with history of htn, then resume BP meds after the first few days.

    --dyslipidemia.

            --intensive statin therapy if LDL >100 if presumed atherosclerotic stroke, even without other evidence of atherosclerotic disease. less strong recommendation if LDL <100

            --still focus on lifestyle interventions

    --glucose disorders

            --screen all pts with stroke/TIA for diabetes. A1C likely to be most accurate in period after acute event.

    --obesity

            --screen with BMI. wt loss is clearly beneficial to improve cardiovasc risk factors, though data on stroke prevention are lacking [several studies have found that BMI is less predictive than waist                 circumference or other measures of abdominal obesity, as noted in prior blogs]

    --physical inactivity

            --3-4 sessions/week of moderate to vigorous aerobic activity (at least breaking a sweat or noticeably increased heart rate), lasting 40 minutes. consider enrollment in program for this

    --nutrition

            --nutrition assessment, counseling if appropriate, not give vitamin supplements, reduce sodium to <2.4 g/d, consider Mediterranean-type diet over low-fat diet

    --sleep apnea

            --consider sleep study (high prevalence of sleep apnea in those with stroke/TIA -- on order of 50-75%!!, and 70-80% of them undiagnosed. clinical history (sleepiness and BMI) not accurate enough;                             CPAP improves outcomes in most studies). Note that they and the Am Acad of Sleep Med suggest routine polysomnography in patients with ischemic stroke/TIA

    --extracranial carotid disease

            --in pts with carotid stenosis (>70% obstruction by noninvasive test, >50% with invasive) and anticipated peri-op complication rate of <6%:

                    --consider carotid endarterectomy if <70 yo

                    --consider carotid angioplasty with stent if younger

            --not recommend routine duplex ultrasound for routine followup after procedure

    --intracranial atherosclerosis

            --in general if ischemic stroke/TIA with 50-99% stenosis of major intracranial artery, use aspirin 325 mg/d

            --if recent stroke/TIA (within past 30 days) and severe stenosis (70-99%) of major intracranial artery, consider adding clopidogrel 75 to aspirin 325 for 90 days

            --for pts with intracranial artery stenosis of 50-99%, 

                    --data insufficient regarding usefulness of clopidogrel alone, combo aspirin/dipyridamole, cilostazol alone (insufficient data)

                    --maintain systolic bp <140 and use high-intensity statin

                    --not recommend stenting in general. use of Wingspan or other stents is considered investigational, even if progressive symptoms, severe stenosis (70-99%), and already taking aspirin plus                                     clopidogrel

    --atrial fibrillation

            --pts with stroke/TIA and no known cause, consider 30-day ambulatory monitoring within 6 months of event

            --vitamin K antagonists, apixaban, dabigatran (apixaban higher level of evidence) are all okay as initial therapy for nonvalvular AF, either paroxysmal or permanent. rivaroxaban is reasonable, though                     lower level of evidence. should be started within 14 days of onset of symptoms

            --adding on antiplatelet therapy not indicated, unless clinically apparent CAD, esp if acute coronary syndrome or stent

            --for patients unable to take anticoagulants, use aspirin alone [though see excerpt from recent afib guidelines below, which downplay aspirin]. addition of clopidogrel "might be reasonable"

    --MI and thrombus

            --use of vitamin K antagonists (INR 2-3) if ischemic stroke/TIA in setting of acute anterior MI with thrombus or without thrombus but with anterior apical dyskinesis, for 3 months. can also use                                     low molecular wt heparin (LMWH), dabigatran, rivaroxaban or apixiaban for 3 months if intolerant of vit K antag

    --cardiomyopathy

            --use vit K antag  for at least 3 months if left atrial or ventric thrombus, or if dilated cardiomyopathy (LVEF<35%), or restrictive cardiomyop . can use dabigatran, rivaroxaban or apixiaban for at least 3                          months if intolerant of vit K antag

    --valvular heart disease   

            --new guideline is to consider adding aspirin to adequate vit K antag if rheumatic mitral valve disease and still get ischemic stroke/TIA

    --prosthetic heart valve

            --new guideline if mechanical mitral valve and history of ischemic stroke/TIA before insertion of valve: goal INR 2.5-3.5

    --antiplatelet therapy

            --consider combo of aspirin and clopidogrel within 24 hours of ischemic stroke/TIA and continue for 90 days

            --adding antiplatelet therapy to vit K antag unclear in patients with stroke/TIA along with atrial fib and CAD. (unstable angina and stents are should get the combo)

    --aortic arch atheroma

            --use antiplatelet and statin therapy. anticoagulation unclear, surgery not recommended

    --PFO

            --if PFO and venous source of embolism, anti-coagulation (or IVC filter if contraindicated). not do PFO closure if no clear venous source, but consider if there is a venous source (eg DVT)

    --hypercoagulation assessment

            --unknown utility to screen (though screening for homocysteine is not indicated). but if hypercoag state found, can consider anticoagulation, or antiplatelet if that is contraindicated

            --anti-phospholipid screen -- not do routinely if other reason for ischemic stroke/TIA identified (eg atherosclerosis, afib, carotid disease). use antiplatelet therapy if anti-phospholipid antiody found

    --pregnancy

            --if condition outside of pregnancy indicating need for anticoagulation, use LMWH bid or subq unfractionated heparin (UFH) throughout pregnancy, though can substitute vit K antag from 13th week til close                 to delivery

            --if low-risk situation and antiplatelet therapy would be considered outside of pregnancy, either use UFH or LMWH or no treatmemnt (but not antiplatelet therapy) in first trimester

    --breastfeeding

            --in situation where anticoag necessary outside of pregnancy, use warfarin, UFH or LMWH. if antiplatelet therapy would have been used, use low-dose aspirin

so, nothing too striking. largely incorporates other guidelines. pretty convincing argument to consider sleep studies more routinely, given the evidence.

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here is excerpt downplaying aspirin in afib from the blog on the new guidelines on management of atrial fibrillation from am heart assn and am acad of cardiol (see afib aha guidelines circ 2014 in dropbox, or 10.1016/j.jacc.2014.03.022)

antithrombotic therapy -- individualized/shared decision-making. 

        --warfarin if mechanical valve (range 2-3 or 2.5-3.5, depending on type of valve/location). 

        --for patients with nonvalvular afib with prior stroke, TIA, or CHA2DS2--VASc score of 2 or greater, recommend oral anticoag. [note they are not using the older CHADS2 score.  options: warfarin with INR 2-3 (level of evidence A); or dabigatran, rivaroxaban, or apixaban (level of evidence B) [ie, they added these factor Xa inhibitors to the list.  though i have sent out recent blogs on the apparent understating of risks of dabigatran in particular]. not use dabigatran in patients with mechanical valves or dabigatran and rivoraxaban if ESRD or hemodialysis

        --they still recommend INR monitoring at least weekly til INR in range, then at least monthly [though, fyi, there was a recent article suggesting that rock-stable patients could be checked every 3 months]

        --for patients with nonvalvular AF and CHA2DS2--VASc score of 0, "it is reasonable to omit antithrombotic therapy". for a score of 1, can do nothing, use aspirin, or anticoagulate [they are downgrading the recommendation that aspirin should be used in low risk patients, given relative paucity of studies -- SPAF is only study showing benefit of aspirin alone]