The Framingham study found an 18% increase in coronary events for males and a 31% increase for females for every 10 cigarettes smoked per day. There is more of an association between smoking and myocardial infarction than between smoking and stable angina. Smoking increases the risk of stroke, coronary heart disease, and peripheral vascular disease through a number of mechanisms (Table 1.11). Smoking is a major factor in the increased risk of coronary heart disease for women using oestrogen-containing contraceptive pills.
Some effects of smoking
1. Increased atherogenesis, probably by toxic injury to endothelial cells
2. Hypoxia, resulting in intimal proliferation
4. Reduction in HDL
5. Oxidation of lipids
6. Increase in fibrinogen levels
Smoking cessation is associated with a rapid decline in death rates from coronary disease,probably because of smoking’s thrombogenic effects. Smoking seems less important as a risk factor in populations with low LDL levels.
Many strategies are available to help patients to give up smoking. These should all begin with an explanation of the reasons smoking cessation is worthwhile. Some explanation of the mechanism of its deleterious effects may be helpful. Patients who have recently presented with possible cardiac symptoms may be amenable to the advice of this nature. It is also especially important to give strong advice about smoking to patients with multiple existing coronary risk factors.The rapidity at which benefits begin to occur, and the risks and difficulties involved in further cardiac treatment (e.g. coronary surgery) for smokers, should be emphasised. The postoperative risk is considerably higher for smokers, particularly for serious chest infections. This risk falls quickly (within four weeks) once smoking is stopped.Nicotine replacement patches may be helpful and appear safe even for patients with ischaemic heart disease. The drug bupropion, which is a non-tricyclic antidepressant, is now available for patients who wish to stop smoking. This drug seems safe for patients with cardiac disease, at least for those without unstable symptoms. It does not cause conduction abnormalities increase the risk of ventricular arrhythmias. Patients should be advised to continue smoking when they first start the drug but plan to stop on a particular day after about a week of treatment. The drug is usually continued for at least seven weeks. The starting dose is 150 mg daily and then 150 mg twice a day.It is important to discuss strategies for smoking cessation with the patient and to try to establish a treatment plan that suits the individual
Evidence of an increased cardiovascular risk from environmental smoke has been available for some years.20 The legislation is gradually reducing the risk for people in occupations associated with smoking (e.g. serving in bars and restaurants) but patients with existing ischaemic heart disease should be advised to avoid exposure.