Dr.S.Venkatesan MD

Aspirin for primary prevention of CVD is an ongoing controversy for more than 2 decades. Please note, the controversy is not in the competence of Aspirin to prevent cardiovascular  event, but in the potential risk of GI bleed and whether that risk is worth taking. Secondary prevention has no such issues as the benefits easily outweigh the potential bleeding risk .

Male vs female

There is a “gender” and “age” difference  in the ability of Aspirin to prevent vascular events.Aspirin primarily prevents MI in men(>45)  and stroke in women(>55)  (Funny it may look,  that’s what data says!)

Age

Hence, the target age group  for aspirin is between 45/55  to 80 years. (Up to 45 and beyond 80 it has no role .Beyond 80 ,  risk of hemorrhagic stroke is significant )

Diabetic vs non diabetic

Many believe  all diabetics should straightway  get Aspirin as it was considered  CAD equivalent.Its not acceptable to all. . American diabetic association  has risk stratified DM and advice Aspirin only in high / Intermediate risk.Look for Key word ie “Net benefit“ (Ref 2)

Why so much confusion  ?  and What can be  the conclusion ?

The confusion is because each scientific body like AHA, ESC, ACCP, ADA ,USPSTF have  their own inference and the presence of too many risk assessment tools adds further dizziness .(SCORE /FRAMINGHAM, etc). It tempts me to say ignore all these and use  cortical sense !

Fortunately ,we do have some clarity as there is a common theme in all these advisories .Aspirin is indeed a wonder drug and able to block the platelets to prevent acute thrombus formation in the critical circulations.(FDA doesn’t seem to agree with this , How can a cheap generic do that job so effectively  ? Let the Bayer fight ! ) 

It seems reasonable to conclude

All men and women  between 45/55  to 80 years should get Aspirin (81mg /day or 325mg alternate days ) if there is at least one or two CVD risk factors provided there is no major bleeding risk .

Ongoing  studies on primary prevention with Aspirin 

ASCEND: A Study of Cardiovascular Events in Diabetes; or with diabetes taking a statin 

ENVIS-ion (Aspirin for the Prevention of Cognitive Decline in the Elderly )

ASPREE (Aspirin in Reducing Events in the Elderly) 

These  studies are  expected to  bring more data (and be ready for more confusion!)

Can we use Clopidogrel  for primary prevention if a person is intolerant to Aspirin ?

Logic may say yes.As of now it can not be advised for primary prevention.

Reference

1.A elegant advisory is hosted in Healthcare Research and Quality (AHRQ) website with supportive data from U.S. Preventive Services Task Force.

2.Pignone  M., Alberts  M.J., Colwell  J.A., et al; Aspirin for primary prevention of cardiovascular events in people with diabetes: a position statement of the American Diabetes Association, a scientific statement of the American Heart Association, and an expert consensus document of the American College of Cardiology Foundation. Circulation. 2010;121:2694-2701

3.Sigrun Halvorsen,Felicita Andreotti,  Jurriën M., Aspirin Therapy in Primary Cardiovascular Disease PreventionA Position Paper of the European Society of Cardiology Working Group on Thrombosis  J Am Coll Cardiol. 2014;64(3):319-327.

2016 Update by USPSTF in Annals of Internal medicine has a Major revision.

It raises concern over bleeding risk, and ask for restricted use of Aspirin

within the age group of 50 -69 for both male and female.(Who are at risk of CAD)

Link to the Annals of Internal Medicine Article  Aspirin primary prevention 2016