Smoking is the Most Important Modifiable Risk Factor
Among the options provided, smoking (B) is the single most critical modifiable risk factor that must be addressed in this patient with established ischemic heart disease and prior myocardial infarction.
Understanding Modifiable vs. Non-Modifiable Risk Factors
The question presents four options, but only two are truly modifiable:
- Family history (A) - Non-modifiable; genetic predisposition cannot be changed 1
- Gender (C) - Non-modifiable; biological sex is fixed 1
- Smoking (B) - Modifiable; can be eliminated through cessation 1
- BMI (D) - Modifiable; can be reduced through diet and exercise 1
Why Smoking Takes Priority
Smoking cessation provides the most immediate and substantial mortality benefit in patients with established coronary artery disease. The 2012 ACC/AHA guidelines for stable ischemic heart disease emphasize that guideline-directed medical therapy (GDMT) includes lifestyle modifications, with smoking cessation being paramount 1.
Evidence Supporting Smoking as the Priority
- In secondary prevention after myocardial infarction, smoking cessation reduces cardiovascular mortality more dramatically than any other single lifestyle intervention 1
- The guidelines specifically identify smoking as a key modifiable risk factor requiring immediate intervention in patients with known ischemic heart disease 1
- Smoking directly accelerates atherosclerotic plaque progression and increases thrombotic risk, making it particularly dangerous in patients with prior MI 2
Why BMI is Also Modifiable But Secondary
While BMI (D) is technically modifiable through weight reduction, smoking cessation provides more immediate cardiovascular benefit and is easier to achieve as a binary intervention (quit vs. continue) compared to the gradual process of weight loss 1. The guidelines mention weight reduction as part of comprehensive risk factor management, but smoking cessation is consistently prioritized first 1.
Clinical Context for This Patient
This patient presents with:
- Exertional chest pain - suggesting ongoing myocardial ischemia 1, 3
- Prior myocardial infarction - placing him at high risk for recurrent events 1, 4
- 3-month symptom duration - indicating stable but active disease 1
In this high-risk secondary prevention scenario, eliminating smoking immediately reduces the risk of recurrent MI, sudden cardiac death, and progression of coronary artery disease 5, 2.
Common Pitfalls to Avoid
- Don't assume all modifiable factors are equally important - smoking cessation has the strongest evidence for mortality reduction in established CAD 1
- Don't delay smoking cessation counseling - every clinical encounter with a smoker who has CAD should include cessation intervention 1
- Don't overlook that this is a secondary prevention scenario - the patient already had an MI, making aggressive risk factor modification even more critical 1, 4
Answer to the Question
B. Smoking is the correct answer as the most important modifiable risk factor in this clinical scenario 1.