Substance abuse is defined as the excessive and/or compulsive intake of a compound that can cause changes in the neurological or biochemical state of an individual. This may be associated with physiological and/or psychological dependence on the compound in question. This intake is categorized as abuse when it leads to significant impairments in the ability to function in occupational and/or societal terms. Substance abuse may lead to deteriorations in existing health complaints, or to the need for treatment for complaints that may have arisen due to substance abuse1. This abuse may be strongly associated with some conditions such as infective disease2.
Cardiovascular disease is the dysfunction or damage to the tissues of the heart or blood vessels (e.g. cardiac muscle, arterial walls) that results in reductions of their inherent capacity to carry out their normal functions. These functions include the regular and consistent ‘pumping’ of blood throughout the body, which is done to supply all parts of the body (including the brain) with nutrients and oxygen. The vascular system (or the network of blood vessels in the human body) is also concerned with exchanging oxygenated blood with de-oxygenated blood from veins to arteries and back again. Without this ability, the body’s tissues would quickly become starved of oxygen. Blood vessels may also transport waste products to the kidneys and harmful materials (including metabolized and unused drug molecules) to the liver, which contributes to their removal from the body.
Some types of cardiovascular disease may also result in physical blockages within blood vessels, which may result in the effects mentioned above, or even the need for surgeries such as cardiac procedures or even amputations. Cardiovascular disease and the subtypes (or conditions) of this are associated with increases in mortality (the risk of death) and reductions in the quality of life for the millions currently affected. These conditions are also associated with many risk factors that, for many conditions, include substance abuse.
Myocardial infarction (MI), more commonly known as heart attack, is the impairment of blood flow to some part of the heart, which may result in extensive damage to cardiac muscle and other tissues due to oxygen starvation4. Myocardial infarctions may manifest as pain in the chest area and in stark decreases in heart function that lasts for several minutes. This may culminate as tightness and extreme discomfort in the chest, loss of consciousness or even death in severe cases. Many cases of myocardial infarction are ‘built up’ over time, due to the effects of other conditions such as atherosclerosis or coronary artery disease. Eventually, this results in enough cumulative cardiac damage—and symptoms noticeable enough—to become apparent as a heart attack.
Cardiac arrhythmias are irregularities in heartbeat, or the rate at which blood is pumped around the body by the heart. A common form of these is atrial fibrillation (also known as A-fib), related to disorders of an atrium (one of the main ‘chambers’ of the heart)5 and the resultant malfunction of atrial electrical signaling. Ventricular fibrillation (or V-fib), in which the other type of chamber (a ventricle) is dysfunctional, is rarer, but can be a more serious condition. V-fib tends to be more closely associated with myocardial infarction5. Arrthymias may be asymptomatic, or perceived as palpitations in the chest, or manifest in other ways. Many forms of arrythmia are not life threatening, but some may precipitate events that lead to a cardiac arrest. This is a rapid decline in the contraction of heart muscles, resulting in cessations of blood circulation. This is an event distinct from a heart attack, but may also be a consequence of one.
These are disruptions of blood vessels in the skull, resulting in bleeding into some spaces around the brain and within the brain. This may manifest as acute intense headaches, and leave the patient with neurological disorders or, even, pulmonary edema (termed neurogenic pulmonary edema, or PNE). Bleeding within the brain may lead to another form of stroke known as a cerebrovascular accident (CVA). Depending on the size and location of interrupted cerebral blood flow, CVAs may result in reductions in functional, cognitive or sensory capacities. Many forms of brain hemorrhage are associated with increases in blood pressure6 – both acutely and from long-standing hypertension.
Atherosclerosis involves the formation of plaques and resulting vessel hardening (sclerosis) along the interior walls of the arteries. Atheromatous plaque is mostly composed of cholesterol and blood proteins. These proteins, including low-density lipoprotein, facilitate the introduction of cholesterol into arteries, but do not remove it. This condition may be related to the consumption of ‘unhealthy’ foods such as foods rich in certain sugars or fats. Some cases of atherosclerosis are also related to genetic disorders such as familial hypercholesteremia. Atherosclerosis may progress to a point at which an artery is nearly totally blocked by cholesterol plaques. This results in considerable interruptions of blood flow through these vessels. Atherosclerosis is associated with adverse effects such as increased risks of heart failure, peripheral artery disease and stroke.
Cardiomyopathy describes damaged or irregular myocardium, or heart muscle. Cardiomyopathy may contribute to the conditions discussed above. There are many types of cardiomyopathy, including dilated and hypertrophic cardiomyopathy7. This disorder may also be associated with many risk factors, including genetics7.
Coronary artery disease is the narrowing (or stenosis) of major arteries feeding the heart with blood. This is often (but not always) related to atherosclerosis8. Coronary artery disease is another common cause of heart attack and congestive heart failure. This is a condition in which the capability of the heart to pump blood is often significantly reduced. Coronary artery disease may be known by other names, including ischemic heart disease and coronary heart disease. As with some other cardiovascular conditions, the development of coronary artery disease may have a genetic component for some patients8.
Hypertension, or high blood pressure, is a condition in which the heart must work harder than usual to keep blood circulation at acceptable levels. Many cases of hypertension are linked to age-related increases in blood pressure9. Estimates suggest that approximately 33% of all adults over 20 years of age are affected by hypertension6. Hypertension may be a risk factor in the development of atherosclerosis, and thus coronary artery disease9. Additionally, long-standing uncontrolled hypertension can lead to the secondary development of cardiomyopathy, arrhythmia and valvular disease, and puts one at higher risk for cerebrovascular accident.
This is a collective term describing the negative effects of oxygen starvation on tissues. Any vascularized tissue or organ system—from the gastrointestinal tract to the nervous system—can be impacted by an ischemic event. Ischemia is particularly relevant to the heart and vascular system, and is a hallmark of myocardial infarction, as above. Ischemia may also occur in the brain as a result of interrupted blood supply. Acute (or sudden-onset) cerebral ischemia is the second most common cause of death10. Estimates suggest that it is responsible for approximately 130,000 deaths per year in the United States, and is the cardiovascular condition most strongly associated with death10. Cerebral ischemia is also known as ischemic stroke or cerebral hypoxia. Another condition closely related to cerebral ischemia is cerebral infarction. Ischemia may be a result of obstructive vascular conditions such as coronary artery disease10. This condition is also associated with hypertension6. A history of ischemia may be associated with reduced chances of surviving a heart attack10.
This is a condition similar to coronary artery disease, in which an artery located away from the heart (usually in an extremity) is obstructed. This may, again, lead to ischemia and death in the tissues affected and is also associated with atherosclerosis11. Peripheral artery disease may also result in pain and discomfort (claudication) in the areas affected, and may be detected by the development of blueness (or cyanosis) in the extremities11.
This is another obstructive cardiovascular condition, in which abnormal levels of coagulation (or blood clotting) results in the formation of large clots within blood vessels. Clotting is the natural response of the body to blood loss, and occurs in tissues to prevent this. However, the disproportional or abnormal expression of blood proteins involved in clotting may result in thromboses. A common form of this disorder is deep-vein thrombosis (DVT), in which a large clot forms in or migrates to a vein in an extremity. This may result in cyanosis and tissue damage, and may need to be addressed through the external sonication of the clot to break it up, or surgery to remove it and the section of an affected vein in which it is located. Thrombosis may be related to atrial fibrillation, hypertension or genetic factors.
This is the blockage of an artery or vein by a thrombus (large clot). If this occurs in an artery, it may result in tissue ischemia and damage. Thromboembolism in some arteries may lead to a cerebral infarction or other form of ischemic brain damage. Thrombroembolism in a vein may lead to peripheral tissue damage, as above, or pulmonary embolism (also known as PE, in which the blood flow to a portion of the lung is blocked).
Some individuals appear to be at higher risk of cardiovascular disease than others. This may be dictated by many factors, including many types of genetic variation12. The abuse of substances such as alcohol and drugs may also be a strong contributing factor in many cases of cardiovascular disorder. The use of these compounds may result in the further deterioration of an existing illness, or even the onset of disease. The role of substance abuse in the conditions as above will be discussed here in detail.
Excessive alcohol intake may be associated with the increased risk of hemorrhages in the blood vessels of the brain3. Alcohol abuse may also lead to cardiomyopathy 3,13. It is also associated with the increased risk of high blood pressure13. Alcohol abuse is a risk factor in the development of hypertension, and this may have a component of genetic susceptibility14. In other words, the development of hypertension may be affected by variations in the gene for aldehyde dehydrogenase, a major enzyme involved in alcohol metabolism14. A study including 73 patients with heart failure found that 17.8% of these had a history of alcohol or substance abuse15.
Heavy alcohol consumption is also associated with other cardiovascular conditions and events, including11:
Tobacco smoking, while still legally and (somewhat) socially acceptable, is linked to a high prevalence of illness and reduced life quality. This may be related to cardiovascular disorder in many cases. Habitual and/or high-volume smoking is regarded as a risk factor for peripheral artery disease17. Smoking is also associated with the increased risk of ischemia and brain hemorrhages6. The nicotine in cigarettes (and in nicotine-replacement products used in smoking cessation) may also be associated with increased cardiovascular risks18.
Illicit (or ‘illegal’) drugs are banned from commercial sale and trade in many countries. This is due to the side-effect profile, addiction potential, often-high tolerance (or increases in dose needed to elicit the same effect in an individual over time) profiles and potential for dependence that are disproportional to those acceptable to several regulatory and drug-approval authorities worldwide. These properties may increase the risk of abuse of these drugs over time.
Illicit drugs, also often referred to as ‘drugs of abuse’, may provide subjectively positive effects initially, but become the basis for habit formation, addiction, physiological or psychological dependence and unpleasant withdrawal over time. Their use may also lead to emotional and behavioral abnormalities, to the extent of the onset of personality change or psychoses. The chronicity of these changes may be related to the length, or extent of abuse.
The more prominent drugs associated with cardiovascular disease are the stimulants and opioid drugs. These may increase the risk of vascular and/or heart disorders by disrupting the balance of certain neurotransmitters, called catecholamines, in the body and brain. This may lead to dose dependent changes in blood pressure, abnormalities in the normal rhythms of the heart or blood vessels, increased blood clotting and increased arterial plaque formation3. This may result in abrupt, albeit often temporary, deteriorations in patients with conditions related to these effects3. However, this may increase the risk of serious events such as heart attacks, especially with long standing abuse.
This is a class of drugs that contain some derivatives associated with the treatment of conditions such as attention-deficit/hyperactive disorder (e.g. the compounds of dextroamphetamine and methylphenidate in Adderall and Ritalin), and the increasingly popular street drug of abuse, methamphetamine.
The common illegal stimulant cocaine is linked to the greatest incidence of cardiovascular disorders and adverse events. These include the same conditions and effects as for amphetamines3. Cocaine intake is associated with a stark rise in heart rate, blood pressure and the need for oxygen in heart muscle22. In contrast, blood flow is usually seen to be depressed22. In addition to its effects on neurotransmitters, cocaine appears to cause damage and death in cardiac muscle by upsetting the balance of calcium at a cellular level23. This increases the risks of hypertension, stroke, aneurysm and damage to cardiac tissue22. This in turn may affect the probability of a heart attack and heart rate irregularities22.
Cocaine use on its own is dangerous, but combining it with other forms of substance abuse can intensify cardiovascular risks. For example, the metabolism of cocaine in the presence of ethanol (e.g. from combining cocaine and alcohol use) can result in formation of an extremely cardiotoxic metabolite, known as cocaethylene.
The abuse of cocaine is also linked to the increased risk of infections of heart muscle and other cardiac tissues22. This leads to conditions such as endocarditis, which in turn may result in the increased risk of hospital re-admission for conditions such as stroke, arrythmia, heart attack and heart failure25. Approximately half a million people attend emergency departments with complications related to cocaine use, many of which are concerned with chest pain and discomfort indicating cardiovascular events, every year26.
Opioids are in a class of drugs that mimic the body’s natural endorphins, which bind to ‘pain’ receptors to inhibit their signaling to the brain. Therefore, opioids, when ingested or injected, may effectively and rapidly reduce pain awareness. Some of the earliest drugs, including heroin, are opioids. The opioid morphine is regarded as a ‘gold standard’ in pain management research. These drugs also have neurological effects beside analgesia, which may include euphoria, lethargy, respiratory problems and withdrawal symptoms. These drugs have exquisitely pronounced potential for addiction and abuse. Opioid abuse—especially with an intravenous route of administration—is associated with the increased risk of infectious disease, including hepatitis C19. Some researchers assert that this is also influenced by other factors, including stability of abode (e.g. homelessness) and taking these drugs in unhygienic conditions19.
Steroids are a class of drugs that mimic many hormones and other physiological regulatory molecules in the body. As such, they have the potential to disrupt the balance of one or more of these when taken as medications or as performance-enhancing drugs. This may result in many biochemical abnormalities, which may manifest as symptoms of disease or hormonal imbalance. These include changes in blood pressure and other cardiovascular anomalies. Many athletic authorities and governing bodies ban the use of these drugs, particularly those associated with increases in muscle mass (i.e. anabolic steroids)29. Anabolic steroids are linked to the increased risk of many cardiovascular disorders, including29:
Anabolic steroids include testosterone and its derivatives29. Other non-steroidal drugs associated with similar effects on muscular structure include clenbuterol. This substance is also associated with deteriorations of heart muscle tissue29.
Energy drinks are commercially produced beverages typically containing a high concentration of caffeine and, in some cases, refined sugars. They may also contain less-studied compounds linked to improvements in alertness and energy levels, such as taurine or guarana. Concerns about the potential harms of energy drink abuse have arisen in the last few years30. This may involve the regular consumption of these beverages in volumes greater than those recommended by the manufacturer and/or health authorities30. Another dimension of energy drink abuse may be in their combination with illicit drugs or alcohol30. We’re in the midst of an age of energy drink cocktails and mixers – with potentially negative physiologic consequences.
These forms of substance abuse are linked to increased risk of neurological or cardiovascular disorders30. A recent review of the literature on the subjects of energy drinks, their abuse and associated conditions found that, while low to moderate consumption in adults was not associated with harm, the heavy or abuse-related intake of these products was associated with the increased risk of many conditions, including psychiatric illnesses30. This was particularly relevant to those with pre-existing cardiovascular disease30.
Another concern in the management of cardiovascular disease is the combination of drugs, which increases the risks of some adverse effects due to drug-drug interactions. This may include the combination of alcohol with illicit drugs, or with prescription drugs. These legal substances may include medications indicated for cardiovascular disorders, which often interact to negative effect with alcohol31. A review of data from the American National Health and Nutrition Examination Survey found that the rate of alcohol/prescription drug combination was 41.5%31. This rate, when adjusted for age (65 years or more) was 77.8%. In many cases, the medications in question were for cardiovascular conditions31. Another major study on aging found that 72% of its approximately 3800 participants used medications that interact with alcohol, most often drugs for cardiovascular or neurological conditions32. Approximately one in five of these people combined heavy alcohol intake with anti-clotting agents and other drugs for cardiovascular disease32. Older people (who may be at a higher risk of cardiovascular disease) often have an increased probability of drug/alcohol interaction due to age-related decreases in the ability to absorb and metabolize these compounds.
The effects resulting from cardiovascular drug interactions may include32:
Marijuana or cannabis is another (mostly) illicit drug that may play a role in the risk of cardiovascular disease. This substance may be linked to increased risks in middle-aged adults, but this association has still not been confirmed33. There is also some evidence that cannabis use increases the risk of cardiovascular disease in younger people with or without other risk factors34. This may be due to the fact that many people who use cannabis also have a history of tobacco-smoking33. For a long time, cannabis was not associated with abuse. However, recent evidence concerning impairments in cognitive, attentional and executive functions (particularly those involved in operating motor vehicles), addiction, and the increased risk of psychiatric disorders with prolonged or high-volume use of this substance, may change that perception35,36.
The need for advice and education for cardiovascular disease patients (or those at an increased risk of these disorders) on the effects of drug abuse on the heart and blood vessels is clear. This information may be supplied by medical professionals. Screening for substance abuse in those with cardiovascular disease may also be helpful, as may patient education in the course of screening programs for this form of disease itself.
Some evidence on the role of psychiatric illnesses on the risk of substance abuse may indicate the need for improved mental health screening and services in those with cardiovascular disorders. A study of mental health in heart failure patients found that the prevalence of substance or alcohol abuse was associated with major depressive disorder15. Another study using data from over 1000 patients with cardiovascular disease found that a history of trauma was associated with substance abuse in this population38. This may indicate that the improved availability of counseling to people with mental health disorders and an increased risk of cardiovascular disease may reduce substance abuse, and its further deleterious effects on heart health, in this population. Patients reporting to treatment centers for substance abuse may take the opportunity to tell doctors about their psychological issues19.
Cardiovascular disorders are diagnosed using a number of techniques and types of equipment. These may include37:
The use of one or more of these may be ordered by a health professional if a patient presents with cardiovascular symptoms that may be linked with substance abuse37. However, ECGs are often found to be inconclusive in cases of cocaine-related symptoms, possibly due to the changes in blood flow and heart rate associated with the drug23. There are some standard treatments for symptoms found to be related to drug or alcohol abuse, such as nitroglycerin and calcium-channel blockers for cocaine-induced pain or discomfort23.
Patients diagnosed with cardiovascular disorders may also be advised on the potential dangers of alcohol and tobacco abuse. These individuals may be encouraged to reduce or discontinue their intake of these substances, such as cigarettes. Smoking cessation may be achieved through pharmacological replacement therapies. These may include18:
A review of 67 clinical trials of these treatments found no association between bupropion or varenicline and cardiovascular risk, and a negative association between varenicline and serious events18. However, there was an association between the risk of more minor events (but not major events) and replacement nicotine therapy18.
These drugs may be effective in reducing blood pressure or cholesterol levels. However, they may be associated with adverse effects and risks. These may be magnified by alcohol abuse, as described above.
Cardiovascular disorders are treated with a range of pharmacological therapies and other interventions, which may include exercise. Drugs for conditions such as atherosclerosis and hypertension include:
Substance abuse is one of the leading modifiable factors affecting the risk of death. It is also associated with increased uptake of healthcare resources, particularly emergency medicine facilities. It is currently regarded as a major healthcare and social issue.
Substance abuse may pose risks to other organs and parts of the body, including the gastrointestinal system, brain and kidneys. As seen above, these risks are influenced by alcohol abuse in combination with prescription drug intake. This may affect mortality and life quality of the patients affected.
Substance abuse is often difficult to diagnose, and may be complicated by other health issues such as cardiovascular disease. As illustrated, the combination of both can lead to serious complications and death. Seeking treatment for substance abuse may contribute to the long-term cessation or control of these problems19. This may also afford the opportunity to address and manage other health problems that may be associated with this, including cardiovascular disease. Depending on the state (or country) concerned, substance abuse may be provided in outpatient clinics, private facilities, rehabilitation clinics or community healthcare clinics. The management of both cardiovascular disorder and substance abuse is often best served by assistance from qualified healthcare professionals who may specialize in either. A consultation may be the first step on the road to recovery from substance abuse. Seeking medical advice for suspected conditions and/or worrying symptoms such as chest pain resulting from substance abuse is also recommended.