Angina and Smoking

Introduction to Angina

Cardiovascular disease is a major cause of mortality and morbidity across the globe. It presents as various clinical manifestations and conditions such as ischemic heart disease, heart failure, dysrhythmias, and vascular disease.¹ Angina is a heart condition causing constricting discomfort in the front of the chest or the neck, shoulders, and/or arms. It is caused by a lack of oxygen to the heart muscles and is a common clinical symptom of ischemic heart disease (IHD). It is prevalent in 3–4% of UK adults.² Symptoms include a constrictive feeling in the centre or the right side of the chest with associated symptoms like shortness of breath, pain in the arms, neck, throat, and back, accompanied by cold sweats, nausea or vomiting, and rarely, syncope (fainting).³ The common causes of angina are coronary artery spasm, atherosclerosis, platelet aggregation, hypoglycemia, and increased metabolic rate.⁴  

How does Smoking impact Angina?

Tobacco smoking has two phases, gas and tar-phase smoke, with smoke from cigarettes containing 92% gas and 8% tar.⁵ Smoking causes the release of approximately 4000 chemicals, which later combine with various biological agents in the body leading to numerous pathophysiological changes.⁶ Some of the most common chemicals are described below. 

Tar

Tar is a sticky substance formed while burning tobacco. It causes the yellowish-brown discolouration of the teeth and fingernails. When tar sticks to the arterial walls, it causes atherosclerosis. It also leads to platelet aggregation, making the blood thicker, which causes a decreased blood supply to the terminal arterioles.  

Nicotine

Nicotine is an addictive chemical, and it leads to a decrease in the blood flow to the heart muscles.⁷ It has an average half-life of about 2 hours.⁸ Nicotine causes the release of adrenaline in the body. This causes heart rate and blood pressure elevation and increased contractility of the heart muscles, which causes an increase in cardiac output, leading to constriction of blood vessels.⁷ According to the American Heart Association, nicotine also causes the arterial walls to lose elasticity; as a result, the walls cannot adjust to changes in blood pressure well, thereby increasing the risk of a heart attack.⁹ 

Carbon Monoxide

Carbon monoxide (CO) has a higher affinity (binding strength) to haemoglobin in the blood than oxygen. As a result, the blood cells cannot transport as much oxygen, which is also known as a reduced oxygen-carrying capacity. This causes hypoxia in the tissues.¹⁰ CO concentration of 10% or more in smokers is considered poisoning that can induce coronary artery spasms, resulting in variant angina.¹¹ The American heart association states that CO impacts the inner lining of the blood vessels by resulting in increased cholesterol deposition, ultimately leading to heart attack and other heart-related diseases. ⁹

Smoke 

Smoking has a marked impact on the lipid profile of the users. It leads to an increase in the LDL (Low-Density Lipoprotein), triglycerides and VLDL (Very Low-Density Lipoprotein) levels, and a marked decrease in the HDL (High-Density Lipoprotein) levels. It also leads to an increase in red and white blood cell count.¹³ Smoking increases insulin resistance, thereby leading to increased blood insulin levels. This causes an increase in LDL, VLDL, and triglycerides because of the consequent decrease in enzymatic activities in the pathway that converts VLDL to LDL.¹⁴ Nicotine, which is associated with tobacco smoking, stimulates the secretion of adrenaline, which increases the levels of free fatty acids in the blood.⁸ 

Why you should stop smoking

Studies have shown that people who quit smoking live longer than those who do not. It is applied to all age groups, but it is most effective if done by the age of 35 years.¹⁵ Smoking cessation leads to a marked reduction of atherosclerosis and its progression, thereby reducing the risk of death due to cardiovascular disease. It also leads to an increase in HDL levels.¹⁶