It is very important to understand the difference between primary and secondary prevention. Primary prevention relates to preventing a disease happening in the first place. Secondary prevention however relates to preventing a further event happening when a cardiovascular event has already occurred.
All prevention both primary and secondary involves lifestyle management. There are many approaches to a healthy lifestyle, a vast literature and any amount of advice available, however there are some fundamental principles which almost all mainstream opinion agrees on:
Do not smoke, and where necessary seek help from a smoking cessation clinic. Take plenty of exercise where possible and a calorific intake commensurate with the amount of exercise you do such that you achieve a health weight (or to be more objective a health Body Mass Index-BMI). Take a diet which is low in salt, sugar and saturated fatty acids whilst being replete in omega-3 fish oils. Avoid excessive consumption of alcohol.
Whilst adopting a healthy lifestyle is always wise, it is important to consider drug therapy where appropriate. The mainstays of preventive drug therapy are treatment of high blood pressure, high cholesterol and high sugar. In some instances blood thinning therapy may be necessary to reduce the risk of heart attack, stroke and blockage of other blood vessels.
As a rule, in primary prevention drug therapy may not be necessary and if needed may not need to be too aggressive. In secondary prevention however where an event (eg heart attack) has already happened, aggressive drug therapy is usually essential since the patient is at much higher risk of a future event and the risk factors must be aggressively controlled to reduce this risk as much as possible.