Clearing the Smoke Assessing the Science Base for Tobacco Harm Reduction (2001) / Chapter Skim
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13 Cardiovascular Disease
13 Cardiovascular Disease
Pages 470-499
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From page 470... ...
The cardiovascular burden of smoking is amplified substantially because smoking significantly increases the risk for many types of cardiovascular morbidity: myocardial infarction (MI) , sudden cardiac death, stroke, peripheral vascular disease, and abdominal aortic aneurysms (Green et al., 1993~.
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From page 471... ...
In considering the participation of smoking in the etiology of CHD, it is useful to separate the effects of smoking on the development of atherosclerotic stenosis of the coronary arteries from its effects on the process that converts coronary atherosclerosis to acute coronary events. Acute coronary events represent an abrupt transition from stable chronic CAD to one of the major consequences of ischemia: unstable angina, myocardial infarction, and sudden cardiac death.
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From page 472... ...
However, excess smoking-attributable mortality rates due to heart disease continue to increase with age and smoking duration, suggesting that smoking continues to be an important independent risk factor in the elderly (Burns, 2000~. Acute Coronary Events Prospective epidemiological studies have consistently demonstrated a substantial increase in acute coronary ischemic events in individuals who smoke (U.S.
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From page 473... ...
Cessation of Smoking Smoking cessation in individuals without known coronary heart disease makes an important contribution to reducing the risk of MI (Cook et al., 1986; Rosenberg et al., 1985, 1990; U.S.
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From page 476... ...
The decline of risk upon smoking cessation can be variable in different risk groups and according to behaviors during cessation, potentially affording insight into interindividual differences in mechanisms relevant to healing smoking-induced cardiovascular injury. An initial interpretation of these data suggested that acute factors, such as hemostatic activation, dominated over more gradual processes, such as occlusive atherosclerotic
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From page 477... ...
Smoking and Other Cardiac Risk Factors Cigarette smoking, hypercholesterolemia, and hypertension have been the most extensively studied risk factors for CAD. The risk of CAD imposed by cigarette smoking is magnified by the presence of several other factors that cause coronary heart disease.
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From page 478... ...
Pathophysiology A review of the mechanisms linking cigarette smoking and coronary heart disease must consider the fact that whereas smoking accelerates
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From page 479... ...
Although there is likely overlap between the mechanisms by which smoking accelerates atherosclerosis and promotes acute ischemic events, it is useful to consider these adverse effects of smoking separately. Acceleration of Atherosclerosis As for other risk factors, vascular endothelial dysfunction likely plays a central role in the promotion of atherosclerosis in chronic smokers (FitzGerald et al., 1988; Heitzer et al., 1996a)
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From page 480... ...
Promotion of Acute Coronary Events In addition to the effect of smoking on the development of atherosclerosis, there is a dramatically increased risk of acute ischemic events, including MI and sudden death. Acute systemic and coronary hemodynamic effects of smoking are likely to play an important role in the development of these ischemic events.
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From page 481... ...
Most research on the effects of smoking on the cardiovascular system has focused specifically on nicotine and carbon monoxide, but there are more than 4,000 other components in cigarette smoke, some of which may also contribute to smoking-induced vascular disease (Penn and Snyder 1996~. Coronary Vasospasm A much less common cause of ischemia than plaque rupture, primary coronary vasospasm usually manifests as variant angina but may also cause MI and sudden cardiac death.
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From page 482... ...
Increased insulin resistance has been associated with increased intimalmedial thickening in the presence of vasospastic angina (Shinozaki et al., 1997~. The syndrome occurs in healthy young men and is sixfold more common in cigarette smokers (Tahtinen et al., 1998~.
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From page 483... ...
or IL-8 and ICAM-1 in small respiratory airways (Takizawa et al., 2000~. Homocysteine Blood homocysteine levels have been related to an increased risk of coronary heart disease and other atherosclerotic diseases in several studies (Saw, 1999~.
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(Brash et al., 1983) , is also elevated in chronic cigarette smokers.
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From page 485... ...
Such surrogates could represent an intermediate link between the noninvasively acquired biochemical indices and true functional outcomes of smoking, such as myocardial infarction and sudden death. Another mechanism that has been widely implicated in cigaretteinduced tissue injury is oxidative stress.
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From page 486... ...
on arteries throughout the body and in the lungs and heart include measurements of platelet activation, blood pressure and heart rate, and oxidative stress. Other surrogate markers that may be utilized in clinical studies include measurements of oxidative stress, measurements of platelet activation, elements of the coagulation system, lipids and lipoproteins, pulmonary function studies, studies of endothelial function, myocardial stress perfusion studies, and periodic evaluation by ultrasound of the carotid, abdominal aortic, and lowerextremity arteries.
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From page 487... ...
Although this may represent saturation kinetics of nicotine or CO, the most likely explanation is compensation for lower numbers of cigarettes smoked. Thus, the smoker titrates nicotine delivery toward a range of convergence that is reflected by the measurement of nicotine delivery, which in turn, may reflect dosedependent convergence of the delivery of additional toxic, but unmeasured, constituents of cigarette smoke.
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From page 490... ...
These observations may, in turn, be related to the pattern of gene expression and translation in cardiovascular tissues obtained from cigarette smokers. Biomarkers of Tobacco-Related Disease The predominant mechanisms by which cigarette smoking induces cardiovascular injury is unknown.
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From page 491... ...
, including: activation of platelet function; endothelial function; endothelial thickening and plaque formation; blood pressure and heart rate alterations; vascular aneurysm formation; vascular thrombosis (arterial and venous) ; cardiac electrophysiology, including ventricular and atrial ectopy, heart rate variability, and variations in conduction times, especially QT intervals; and other risk factors for cardiovascular disease including lipid and carbohydrate abnormalities, homocysteine, folic acid and antioxidant vitamins, markers of inflammation, and immune function.
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From page 492... ...
Such studies might include the use of gene array and proteomic technologies to study differential gene expression and translation; the use of chronic exposures to investigate effects on atherosclerosis progression, response to thrombotic and arrhythmogenic stimuli, and cardiovascular disease development; and studies of the effects of cigarette smoke and its constituents on the function and integrity of cardiovascular cells in vitro, including platelets, leukocytes, endothelial cells, vascular smooth muscle cells, and myocytes.
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From page 493... ...
1989. Short-term effects of carbon monoxide exposure on the exercise performance of subjects with coronary artery disease.
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1993. Cigarette smoking antioxidants, lipid peroxidation, and coronary heart disease.
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1997b. Smoking cessation and decreased risk of total mortality, stroke, and coronary heart disease incidence in women; a prospective cohort study.
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1999. C-Reactive protein, a sensitive marker of inflammation, predicts future risk of coronary heart disease in initially healthy middle-aged men: results from the MONICA (Monitoring Trends and Determinants in Cardiovascular Disease)
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2000. Prognostic value of coronary electron-beam computed tomography for coronary heart disease events in asymptomatic populations.
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1996. Environmental tobacco smoke and coronary heart disease in the American Cancer Society CPS-II cohort.
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From page 499... ...
1978. Relationship of blood pressure, serum cholesterol, smoking habit, relative weight and ECG abnormalities to incidence of major coronary events: final report of the pooling project.
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