Cardiovascular module

EBM-Systematic Review GROUP Exercise

Group 8:

Edward Eid, Nour Gebara, Lana Khalil, Ali Rteil, Elie Toni Korbani, Bachar Chaya

Case scenario

Mr. Ibrahim is presenting to your clinic for his yearly check-up. He is a 55 year old male who’s been hypertensive for the past 10 years, and smoker of one pack per day. Mr. Ibrahim is very concerned since his father passed away with an acute myocardial infarction at the age of 49. He was once advised to take a baby aspirin daily for “prevention” of heart attack. He is worried however, because a friend had an intracranial hemorrhage while on aspirin for primary prevention of cancer, as advised by his physician. Mr. Ibrahim knows that aspirin is a “blood thinner” and seeks your advice regarding aspirin use.

1. Phrase the question(s) using the PICO strategy

In the case presented, the patient is concerned about the use of aspirin. Specifically, he wants to know: 1- how effective is aspirin use in preventing the occurrence of heart attack, and 2- the possible side effects of using aspirin (in particular intracranial hemorrhage). Since this question can be tackled in two ways, we will divide it into two research questions with a separate PICO.

A- For 1 st concern: Population: A 55 year old, hypertensive male smoker, with a history of familial

myocardial infarction Intervention: Aspirin prophylaxis Comparison : no aspirin prophylaxis or placebo Outcome : Prevention of heart attack

Question: For a 55 year old, smoking, hypertensive male with familial history of myocardial infarction, could aspirin administration as compared to no aspirin administration prevent the occurrence of heart attacks?

The PICO question above is a question of therapy.

B- For 2 nd concern :

Population : A 55 year old, hypertensive male smoker, with a history of familial myocardial infarction

Intervention : Aspirin prophylaxis Comparison : no Aspirin prophylaxis or placebo Outcome : adverse effect of intracranial hemorrhage

Question: For a 55 year old, hypertensive smoker male with familial history of myocardial infarction, could the use of aspirin prophylaxis as compared to no aspirin use cause intracranial hemorrhage?

The PICO question above is a question of harm.

2) Search for a systematic review that addresses the patient’s question(s) using PubMed Clinical Queries.

A

1. Initially, our search strategy tackled the first PICO question concerned with the efficacy of aspirin prophylaxis in the primary prevention of cardiovascular events.

2. On the PubMed Clinical Queries page, we included all of the associated risk factors (smoking, age, hypertension, male) along with primary intervention, cardiovascular events, and aspirin. We separated each individual term by “AND” and all of the synonyms by “OR”. Ultimately, we came up short in terms of systematic reviews.

3. Thus, we decided to include hypertension as the sole risk factor in the search for 2 reasons: Hypertension’s association with cardiovascular events is very powerful and we needed to broaden our search to include more systematic reviews in our findings. The search field read: (hypertension OR elevated blood pressure OR high blood pressure) AND primary prevention AND (aspirin OR antitplatelet therapy OR antithrombotic therapy) AND (cardiovascular disease OR myocardial infarction OR MI OR ischemic events).

4. Our search yielded 458 systematic reviews; it was now time to further narrow our results in order to find the best one (scroll down and press “See All”).

5. We now applied filters for: article type (systematic reviews) species (Humans), sex (male), Ages (45+ years; middle aged) [terms in parentheses were checked]. Our filters yielded a manageable 117 systematic review whose titles could be scanned to answer our target question.

6. We eventually found a systematic review entitled “Meta-analysis of data from the six primary prevention trials of cardiovascular events using aspirin” that was pertinent in answering the question at hand. Moreover, the review is dated to 2006, thus ensuring that the results are relatively recent.Link: http://www.ajconline.org/article/S0002-9149(06)01068-X/pdf

7. After downloading and reading the systematic review, the conclusion was in favor of aspirin’s positive effect on preventing the incidence of cardiovascular events but maintains that aspirin should be utilized as primary prevention only in high-risk patients (since aspirin does contain harmful side effects).

B-

1. We now shift our focus to the 2nd PICO question dealing with the harmful side effects of aspirin in the primary prevention of Cardiovascular Disease.

2. In the PubMed Clinical Queries, we looked for the terms relevant to our search including in the search field: (Cardiovascular events OR myocardial infarction OR MI) AND primary prevention AND intracranial hemorrhage AND (aspirin OR antiplatelet therapy OR aspirin prophylaxis). We obtained 11 results as shown below. There was no need to play with the filters for they had already been selected in the previous search (refer to step 5 in A) .

3. Of these results, one systematic review stood out. It was one titled “Aspirin in primary prevention of cardiovascular disease and cancer: a systematic review of the balance of evidence from reviews of randomized trials from reviews of randomized trials”. In addition, the fact that this review is recent (2013) also makes it a good source.

Link: http://www.ncbi.nlm.nih.gov.ezproxy.aub.edu.lb/pmc/articles/PMC3855368/pdf/pone.0081970.pdf

4. The systematic review lent credence to the fact that aspirin does in fact cause a moderate decrease in the risk of cardiovascular occurrence; however, the negative side effects associated with it are too dangerous to warrant its use as primary prevention of cardiovascular events (check the highlighted lines in the picture below).

Conclusion

From the searches conducted aimed at answering the patient’s concerns, we can conclude that despite the fact that aspirin administration does decrease the risk of cardiovascular incidences, its harmful side effects (which include hemorrhage) exceed the benefits. Thus, given that this patient is at high risk for cardiovascular incidence (male, middle age smoker with familial history of CVD) we advise him to consider other safer prophylaxis measures.