Managing CVA in Primary Care

Question 1

Pathophysiology of stroke

Answer 1

• Ischemic (occlusive) vs hemorrhagic – 80% of strokes are ischemic!!
  
  • Usually means occlusion – from plaque, afib
  • Afib is one of the most common causes of ischemic stroke
  • Non clot related causes of ischemic stroke – artery dissection (reduces blood flow), CHF, decreased CO
• Whats the problem with ischemic stroke? Oxygen starved
• Solution to ischemic stroke? FIX THE CAUSE!! REPERFUSE AREA
• What causes hemorrhagic? -Dissection, aneurysm ruptures, anticoagulation, trauma
• Primary pathologies are cardio or peripheral vascular disease
• HTN (pressure is always bad! Causes damage overtime), atherosclerosis, dyslipidemia
• Afib, valve disorders, atherosclerosis in carotids and cerebral vasculature
• The clot likes to hang out in the fork in the vasculature because there are little eddies there

Question 2

management of stroke patients

Answer 2

• Recovery
  
  • Manage effects/debility related to stroke: PT/OT
    
    • Talk about what lingering symptoms they have
    • Talk to spouse
    • Try to assess how functional he is relative to prior to the stroke
    • Want to refer them to people who will help them adapt to their new normal
  • Manage risk:
    
    • HTN – want to double down on the aggressiveness with which we handle it
    • Lipids – aggressively manage
    • Platelets
    • We need to think about whether or not aspirin is good enough anymore

Question 3

Pharmacology: statins

Answer 3

• HMG coA reductase inhibitors
• Competitive inhibition of rate limiting step in biosynthesis of cholesterol
• Effect on liver pathway – source of most circulating cholesterol
• Most have short half lives – taken at night to maximize effect when liver is productive
• STATINS DON’T DO ANYTHING ABOUT THE FATS THAT YOU INJEST!!! They only affect the cholesterol that you MAKE in the liver!!!
• They have a better effect if you pair the medication with lifestyle changes
• Take them medicine at night when the liver is productive

Question 4

SPRACL trial

Answer 4

• Statins Reduced CVA risk 3.4-2.7%
• High dose Atorvastatin (80mg) reduce risk of recurrent stroke and major event over 5 yrs
• Some concern about more hemorrhagic strokes in treatment group (55 vs 33)
• Benefits thought to outweigh risks – prevented more strokes than they caused

Question 5

HTN and stroke

Answer 5

• Metanalysis – 10 mmHg reduction in SBP decreases risk by 1/3 WHETHER OR NOT YOU ARE HYPERTENSIVE
  
  • PRESSURE IS ALWAYS BAD!!! If you can reduce your pressure, you can reduce your risk
  • Coronary arteries perfuse in diastole – if you drive the blood pressure too low, you may be promoting ischemia ASK KATIE WHAT THIS MEANS
• Risk reduction continues for every 10 mmHg down to 115/75
• No optimal regimen established – people respond to antihypertensives differently
  
  • There’s no particular drug that reduces the risk any more than another drug – the point is to reduce the PRESSURE
• Lowering BP more important than agent used
  
  • Volume: Diuretics/ACEI
  • Tone: CCB

Question 6

Pharmacology of anticoagulants

Answer 6

• We know he has PVD so we don’t want to aggressively manage his BP, but a little BP control may reduce the risk of another one
• Aspirin: 300-1300mg/day
  
  • Inhibits cyclooxygenase, prevents thromboxane A2 formation, platelet activation and aggregation
  • Decreased risk by 22%
  • Risk reduction equivalent at low and high doses
  • Expert panel: 50-100mg/day
• Aspirin is equally effective at every dose, so 81 mg maximizes the effect

Question 7

Aspirin and Extended Release Dypyrimidole (ASA-ERDP)

Answer 7

• increasing the dose of aspirin wont do anything because its equally effective at all doses
  
  • The Diypyrimidole is a possible vasodilator, inhibits platelet enzymes
  • Trials (ESPS-2 and ESPRIT) demonstrated improved risk over aspirin alone without bleeding risk
  • But: BID dosing and less well tolerated (3x d/c rate; HA worst SE) and expensive
    
    • Taking 1 a day showed better adherence than taking 2 or 3, etc.
    • Reserved for “ASA failures” – our guy is considered an aspirin failure person because he had a stroke on aspirin

Question 8

Clopidogrel

Answer 8

• Inhibits ADP-dependent platelet aggregation
• CAPRIE and ProFESS trials
• Improved stroke risk relative to ASA in pts with PVD
• No significant risk reduction in pts with previous ischemic stroke (MATCH Trial)
• Combination increases bleeding

Question 9

Carotid endarterectomy

Answer 9

• Carotid endarterectomy
  
  • Multiple trials demonstrate efficacy in treating carotid stenosis
  • Fatal ipsilateral stroke or post-operative death decreased from 26% to 9% for those with severe symptomatic stenosis (70-99%occlusion)
    
    • Decreased risk with carotid endarterectomy
  • Pts with moderate stenosis (50-69%) had benefit to 5 years over medical therapy
    
    • These patients do not get operated on because you have a 6-7% risk of stroke just because you did the surgery!
  • 30d post-operative stroke risk = 6-7%
• Lacunar infarcts – we think that these can contribute to dementia

Question 10

PCSK9 inhibitors

Answer 10

• New injectable cholesterol lowering drugs
• Can reduce LDL by 50% or more, additive effect with statins
• Cholesterol levels in 30s
• Advisory panel recommends approval of evolocumab (Repatha) on June 10, 2015
• Most important for resistant hyperlipidemia as with familial forms
• Evolocumab and alirocumab
  
  • Monoclonal ab which inactivate hepatic PCSK9
  • Involved in degrading LDL receptors
  • Blocking PCSK9 makes receptors more available to pull LDL from blood – dramatically lowers LDL cholesterol