Acute coronary hemodynamic response to cigarette smoking in patients with coronary artery disease

Systemic and Coronary Hemodynamic Effects of Tobacco Products on the Cardiovascular System and Potential Pathophysiologic Mechanisms

Tobacco product usage is the single most preventable cause of death in the United States. Smoking promotes atherosclerosis, producing disease in the coronary arteries, the aorta, the carotid and cerebral arteries and the large arteries in the peripheral circulation. The cardiovascular consequences of tobacco products have been the subject of intensive study for several decades. Despite the overwhelming epidemiologic association between smoking and vascular disease, the pathophysiologic mechanisms by which smoking exerts its deleterious effects remain incompletely understood. This review addresses the acute and long-term systemic and coronary hemodynamic effects of tobacco, with an emphasis of the impact on coronary blood flow and pathophysiologic mechanisms.

Nicotine and Nicotine Replacement Therapy Use During Myocardial Perfusion Imaging

Background

Myocardial perfusion imaging (MPI) is commonly used to assess the presence and severity of coronary artery disease (CAD). A radiopharmaceutical is used before and after patients undergo either exercise-induced stress via a treadmill or medication-induced stress. While certain therapies that are known to influence the accuracy of results are avoided prior to conducting MPI, it is currently unknown whether nicotine and nicotine replacement therapy (NRT) should be avoided, even though they may have significant effects on coronary circulation.

Observations

Nicotine has been demonstrated to have both vasoconstrictive and vasodilatory properties. However, in patients with underlying CAD, vasoconstrictive properties appear to predominate and can allow the disease to appear more severe than it is during MPI. Similarly, NRT products may cause vasoconstriction but to a lesser degree given the lower concentration of nicotine present. Due to the lack of robust studies, the clinical impact of these findings on clinician diagnosis and patient management remains unclear.

Conclusions

Based on the available data, nicotine and NRT should ideally be avoided prior to MPI. The specific time frame in which they would be stopped before conducting MPI differs based on the pharmacokinetics of each product. More studies are needed to analyze the impact of nicotine and NRT on the accuracy of MPI using medication.

Pathophysiologic Mechanisms of Tobacco Smoke Producing Atherosclerosis

INTRODUCTION

Despite the convincing epidemiologic association between smoking and vascular disease, the pathophysiologic mechanisms by which smoking initiates and contributes to the progression of atherosclerosis remain incompletely understood. A precise dose-dependent correlation has never been demonstrated, suggesting that the biological relationship is complex and influenced by individual genetic and possibly environmental factors. Although endothelial dysfunction and intimal damage appear to be central to atherogenesis, how tobacco products cause this effect has not been established. The purpose of this review is to describe the current state of knowledge of the main pathophysiologic pathways of how tobacco smoking abets atherosclerosis. Constituents of Tobacco Smoke: Tobacco combustion produces a mixture of organic substances. derived from burning organic materials. The predominant gaseous phase constituents include carbon monoxide, acetaldehyde, formaldehyde, acrolein, and other carbonyls, as well as nicotine and tobacco-specific nitrosamines. Potential Pathophysiologic Mechanisms: Smoking-induced changes in coronary vasomotor tone, platelet activation, and endothelial integrity are major components of both the development of atherosclerosis and its clinical presentation. Smoking may initiate and accelerate the progression of atherosclerosis by injuring the vascular intima. Other potential mechanisms include intimal damage and endothelial dysfunction, oxidative stress and injury, thrombosis, lipid abnormalities, and inflammation.

CONCLUSION

Smoking tobacco products contributes measurably to the incidence of acute vascular events and chronic disease. The causative compound, the exact mechanism of injury, and whether the atherogenic effect is modifiable are not known.

Tobacco Use and Periodontal Disease-The Role of Microvascular Dysfunction

Periodontal disease consists in highly prevalent wide-ranging inflammatory conditions that affect the supporting apparatus of teeth. Tobacco use is the most important risk factor for periodontal disease as it increases disease severity and periodontal surgery complications. Tobacco use is harmful for the vasculature by causing microvascular dysfunction, which is known to negatively affect periodontal disease. To the author's knowledge this paper is the first comprehensive review on the mechanisms by which tobacco use affects oral microcirculation and impacts the pathophysiology of periodontal disease. In healthy subjects, acute nicotine administration or tobacco use (smoking/smokeless forms) increases the blood flow in the oral mucosa due to local irritation and increased blood pressure, which overcome neural- and endocrine-mediated vasoconstriction. Chronic tobacco smokers display an increased gingival microvascular density, which is attributed to an increased capillary recruitment, however, these microcirculatory units show higher tortuosity and lower caliber. These morphological changes, together with the repetitive vasoconstrictive insults, contribute to lower gingival perfusion in chronic smokers and do not completely regress upon smoking cessation. In periodontal disease there is considerable gingival inflammation and angiogenesis in non-smokers which, in chronic smokers, are considerably suppressed, in part due to local immune suppression and oxidative stress. Tobacco exposure, irrespective of the form of use, causes long-term microvascular dysfunction that increases the risk of complications due to the natural disease course or secondary therapeutic strategies.

Comparing the Timeliness of Treatment in Younger vs. Older Patients with ST-Segment Elevation Myocardial Infarction: A Multi-Center Cohort Study

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) predominantly affects older adults. Lower incidence among younger patients may challenge diagnosis.

OBJECTIVES

We hypothesize that among patients ≤ 50 years old, emergent percutaneous coronary intervention (PCI) for STEMI is delayed when compared with patients aged > 50 years.

METHODS

This 3-year, 10-center retrospective cohort study included emergency department (ED) STEMI patients ≥ 18 years of age treated with emergent PCI. We excluded patients with an electrocardiogram (ECG) completed prior to ED arrival or a nondiagnostic initial ECG. Our primary outcome was door-to-balloon (D2B) time. We compared characteristics and outcomes among younger vs. older STEMI patients, and among age subgroups.

RESULTS

There were 576 ED STEMI PCI patients, of whom 100 were ≤ 50 years old and 476 were > 50 years old. Median age was 44 years in the younger cohort (interquartile range [IQR] 41-47) vs. 62 years (IQR 57-70) among older patients. Median D2B time for the younger cohort was 76.5 min (IQR 67.5-102.5) vs. 81.0 min (IQR 65.0-105.5) in the older cohort (p = 0.91). This outcome did not change when ages 40 or 45 years were used to demarcate younger vs. older. The younger cohort had a higher prevalence of nonwhite races (38% vs. 21%; p < 0.001) and those currently smoking (36% vs. 23%; p = 0.005). The very young (≤30 years; 6/576) and very old (>80 years; 45/576) had 5.51 and 2.2 greater odds of delays.

CONCLUSION

We found no statistically significant difference in D2B times between patients ≤ 50 years old and those > 50 years old. Nonwhite patients and those who smoke were disproportionately represented within the younger population. The very young and very old had higher odds of D2B times > 90 min.

Smoking Accelerates Atrioventricular Conduction in Humans Concordant with Increased Dopamine Release

Smoking is associated with cardiac arrhythmia, stroke, heart failure, and sudden cardiac arrest, all of which may derive from increased sympathetic influence on cardiac conduction system and altered ventricular repolarization. However, knowledge of the effects of smoking on supraventricular conduction, and the role of the sympathetic nervous system in them, remains incomplete. Participants with intermediate-high cardiovascular disease risk were measured for urinary catecholamines and cotinine, and 12-lead electrocardiograms (ECGs) were measured for atrial and atrioventricular conduction times, including P duration, PR interval, and PR segment (lead II), which were analyzed for associations with cotinine by generalized linear models. Statistical mediation analyses were then used to test whether any significant associations between cotinine and atrioventricular conduction were mediated by catecholamines. ECG endpoints and urinary metabolites were included from a total of 136 participants in sinus rhythm. Atrial and atrioventricular conduction did not significantly differ between smokers (n = 53) and non-smokers (n = 83). Unadjusted and model-adjusted linear regressions revealed cotinine significantly and inversely associated with PR interval and PR segment, but not P duration. Dopamine, norepinephrine, and epinephrine all inversely associated with PR interval, whereas only dopamine was also inversely associated with PR segment (p < 0.05). Dopamine and norepinephrine (but not epinephrine) also associated positively with cotinine. Dopamine mediated the relationship between cotinine and PR interval, as well as the relationship between cotinine and PR segment. Smoking is associated with accelerated atrioventricular conduction and elevated urinary dopamine and norepinephrine. Smoking may accelerate atrioventricular nodal conduction via increased dopamine production.

Healthcare knowledge of relationship between time series electrocardiogram and cigarette smoking using clinical records

Background

In the few studies of clinical experience available, cigarette smoking may be associated with ischemic heart disease and acute coronary events, which can be reflected in the electrocardiogram (ECG). However, there is no formal proof of a significant relationship between cigarette smoking and electrocardiogram results. In this study, we therefore investigate and prove the relationship between electrocardiogram and smoking using unsupervised neural network techniques.

Methods

In this research, a combination of two techniques of pattern recognition; feature extraction and clustering neural networks, is specifically investigated during the diagnostic classification of cigarette smoking based on different electrocardiogram feature extraction methods, such as the reduced binary pattern (RBP) and Wavelet features. In this diagnostic system, several neural network models have been obtained from the different training subsets by clustering analysis. Unsupervised neural network of clustering cigarette smoking was then implemented based on the self-organizing map (SOM) with the best performance.

Results

Two ECG datasets were investigated and analysed in this prospective study. One is the public PTB diagnostic ECG databset with 290 samples (age 17–87, mean 57.2; 209 men and 81 women; 73 smoking and 133 non-smoking). The other ECG database is from Taichung Veterans General Hospital (TVGH) and includes 480 samples (240 smoking, and 240 non-smoking). The diagnostic accuracy regarding smoking and non-smoking in the PTB dataset reaches 80.58% based on the RBP feature, and 75.63% in the second dataset based on Wavelet feature.

Conclusions

The electrocardiogram diagnostic system performs satisfactorily in the cigarette smoking habit analysis task, and demonstrates that cigarette smoking is significantly associated with the electrocardiogram.

Central and peripheral cardiovascular changes immediately after waterpipe smoking

BACKGROUND

Tobacco cigarette smoking is a global health problem that kills millions each year. Recently, tobacco smoking using a waterpipe (WP) has become popular worldwide. However, unlike cigarettes, the cardiovascular (CV) risks associated with WP smoking are uncertain. In this study, the immediate effects of WP smoking on central and peripheral CV indices were evaluated in 53 young healthy smokers.

MATERIALS AND METHODS

Strain-gauge plethysmography was used to measure forearm blood flow (Bf), vascular resistance (Vr), and venous capacitance (Vc) and outflow (Vf) at rest (R) and after occlusion (Oc), whereas heart rate (HR) and blood pressure (BP) were measured using standard automated auscultatory methods immediately before and after a 30-min WP smoking session.

RESULTS

Smoking resulted in HR, diastolic BP, mean arterial BP, rate pressure product and OcVr increases (p < 0.05) 6.6, 3.6, 2.5, 8.0 and 16%, respectively, whereas OcBf and OcVf decreased (p < 0.05) 8.8 and 14.3%, respectively. Additionally, smoking-induced changes in the central CV components correlated (p < 0.05) with changes in the periphery.

CONCLUSION

These results demonstrated changes in the CV central and peripheral components immediately after WP smoking. The correlations between the changes in these components suggest that the periphery is controlled, at least partially, by the same mechanism(s) affecting the central CV components during WP smoking.

Effects of smoking in patients treated with cardiac resynchronization therapy

Smoking is associated with increased morbidity and mortality in cardiac patients. However, data on the prognostic impact of smoking in heart failure (HF) patients on cardiac resynchronization therapy with defibrillator (CRT-D) are absent. We investigated the effects of smoking on all-cause mortality and on a composite endpoint (all-cause death/appropriate device therapy), appropriate and inappropriate device therapy, in 649 patients with HF who underwent CRT-D between January 2003 and October 2011 in 6 Centers (4 in Italy and 2 in USA). 68 patients were current smokers, 396 previous-smokers (patients who had smoked in the past but who had quit before the CRT-D implant), and 185 had never smoked. The risk of each endpoint by smoking status was evaluated with both Kaplan-Meier and Cox proportional-hazard analysis. After adjusting for age, left ventricular ejection fraction, QRS width and ischemic etiology, both current and previous smoking were independent predictors of all-cause death [HR = 5.07 (95 % CI 2.68-9.58), p < 0.001 and HR = 2.43 (95 % CI 1.38-4.29), p = 0.002, respectively) and of composite endpoint [HR = 1.63 (1.04-2.56); p = 0.033 and HR = 1.46 (1.04-2.04) p = 0.027]. In addition, current smokers had a significantly higher rate of inappropriate device therapy compared to never smokers [HR = 21.74 (4.53-104.25), p = 0.005]. Our study indicates that in patients with HF who received a CRT-D device, current and previous smoking increase the event rate per person-time of death and of appropriate and inappropriate ICD therapy more than other known negative prognostic factors such as age, left ventricular dysfunction, prolonged QRS duration and ischemic etiology.

Interventions for preoperative smoking cessation

BACKGROUND

Smokers have a substantially increased risk of postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence, and surgery may constitute a unique opportunity for smoking cessation interventions.

OBJECTIVES

The objectives of this review are to assess the effect of preoperative smoking intervention on smoking cessation at the time of surgery and 12 months postoperatively, and on the incidence of postoperative complications.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialized Register in January 2014.

SELECTION CRITERIA

Randomized controlled trials that recruited people who smoked prior to surgery, offered a smoking cessation intervention, and measured preoperative and long-term abstinence from smoking or the incidence of postoperative complications or both outcomes.

DATA COLLECTION AND ANALYSIS

The review authors independently assessed studies to determine eligibility, and discussed the results between them.

MAIN RESULTS

Thirteen trials enrolling 2010 participants met the inclusion criteria. One trial did not report cessation as an outcome. Seven reported some measure of postoperative morbidity. Most studies were judged to be at low risk of bias but the overall quality of evidence was moderate due to the small number of studies contributing to each comparison.Ten trials evaluated the effect of behavioural support on cessation at the time of surgery; nicotine replacement therapy (NRT) was offered or recommended to some or all participants in eight of these. Two trials initiated multisession face-to-face counselling at least four weeks before surgery and were classified as intensive interventions, whilst seven used a brief intervention. One further study provided an intensive intervention to both groups, with the intervention group additionally receiving a computer-based scheduled reduced smoking intervention. One placebo-controlled trial examined the effect of varenicline administered one week preoperatively followed by 11 weeks postoperative treatment, and one placebo-controlled trial examined the effect of nicotine lozenges from the night before surgery as an adjunct to brief counselling at the preoperative evaluation. There was evidence of heterogeneity between the effects of trials using intensive and brief interventions, so we pooled these separately. An effect on cessation at the time of surgery was apparent in both subgroups, but the effect was larger for intensive intervention (pooled risk ratio (RR) 10.76; 95% confidence interval (CI) 4.55 to 25.46, two trials, 210 participants) than for brief interventions (RR 1.30; 95% CI 1.16 to 1.46, 7 trials, 1141 participants). A single trial did not show evidence of benefit of a scheduled reduced smoking intervention. Neither nicotine lozenges nor varenicline were shown to increase cessation at the time of surgery but both had wide confidence intervals (RR 1.34; 95% CI 0.86 to 2.10 (1 trial, 46 participants) and RR 1.49; 95% CI 0.98 to 2.26 (1 trial, 286 participants) respectively). Four of these trials evaluated long-term smoking cessation and only the intensive intervention retained a significant effect (RR 2.96; 95% CI 1.57 to 5.55, 2 trials, 209 participants), whilst there was no evidence of a long-term effect following a brief intervention (RR 1.09; 95% CI 0.68 to 1.75, 2 trials, 341 participants). The trial of varenicline did show a significant effect on long-term smoking cessation (RR 1.45; 95% CI 1.01 to 2.07, 1 trial, 286 participants).Seven trials examined the effect of smoking intervention on postoperative complications. As with smoking outcomes, there was evidence of heterogeneity between intensive and brief behavioural interventions. In subgroup analyses there was a significant effect of intensive intervention on any complications (RR 0.42; 95% CI 0.27 to 0.65, 2 trials, 210 participants) and on wound complications (RR 0.31; 95% CI 0.16 to 0.62, 2 trials, 210 participants). For brief interventions, where the impact on smoking had been smaller, there was no evidence of a reduction in complications (RR 0.92; 95% CI 0.72 to 1.19, 4 trials, 493 participants) for any complication (RR 0.99; 95% CI 0.70 to 1.40, 3 trials, 325 participants) for wound complications. The trial of varenicline did not detect an effect on postoperative complications (RR 0.94; 95% CI 0.52 to 1.72, 1 trial, 286 participants).

AUTHORS' CONCLUSIONS

There is evidence that preoperative smoking interventions providing behavioural support and offering NRT increase short-term smoking cessation and may reduce postoperative morbidity. One trial of varenicline begun shortly before surgery has shown a benefit on long-term cessation but did not detect an effect on early abstinence or on postoperative complications. The optimal preoperative intervention intensity remains unknown. Based on indirect comparisons and evidence from two small trials, interventions that begin four to eight weeks before surgery, include weekly counselling and use NRT are more likely to have an impact on complications and on long-term smoking cessation.

Interventions for preoperative smoking cessation

BACKGROUND

Smokers have a substantially increased risk of postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence, and surgery may constitute a unique opportunity for smoking cessation interventions.

OBJECTIVES

The objectives of this review are to assess the effect of preoperative smoking intervention on smoking cessation at the time of surgery and 12 months postoperatively, and on the incidence of postoperative complications.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialized Register in January 2014.

SELECTION CRITERIA

Randomized controlled trials that recruited people who smoked prior to surgery, offered a smoking cessation intervention, and measured preoperative and long-term abstinence from smoking or the incidence of postoperative complications or both outcomes.

DATA COLLECTION AND ANALYSIS

The review authors independently assessed studies to determine eligibility, and discussed the results between them.

MAIN RESULTS

Thirteen trials enrolling 2010 participants met the inclusion criteria. One trial did not report cessation as an outcome. Seven reported some measure of postoperative morbidity. Most studies were judged to be at low risk of bias but the overall quality of evidence was moderate due to the small number of studies contributing to each comparison.Ten trials evaluated the effect of behavioural support on cessation at the time of surgery; nicotine replacement therapy (NRT) was offered or recommended to some or all participants in eight of these. Two trials initiated multisession face-to-face counselling at least four weeks before surgery and were classified as intensive interventions, whilst seven used a brief intervention. One further study provided an intensive intervention to both groups, with the intervention group additionally receiving a computer-based scheduled reduced smoking intervention. One placebo-controlled trial examined the effect of varenicline administered one week preoperatively followed by 11 weeks postoperative treatment, and one placebo-controlled trial examined the effect of nicotine lozenges from the night before surgery as an adjunct to brief counselling at the preoperative evaluation. There was evidence of heterogeneity between the effects of trials using intensive and brief interventions, so we pooled these separately. An effect on cessation at the time of surgery was apparent in both subgroups, but the effect was larger for intensive intervention (pooled risk ratio (RR) 10.76; 95% confidence interval (CI) 4.55 to 25.46, two trials, 210 participants) than for brief interventions (RR 1.30; 95% CI 1.16 to 1.46, 7 trials, 1141 participants). A single trial did not show evidence of benefit of a scheduled reduced smoking intervention. Neither nicotine lozenges nor varenicline were shown to increase cessation at the time of surgery but both had wide confidence intervals (RR 1.34; 95% CI 0.86 to 2.10 (1 trial, 46 participants) and RR 1.49; 95% CI 0.98 to 2.26 (1 trial, 286 participants) respectively). Four of these trials evaluated long-term smoking cessation and only the intensive intervention retained a significant effect (RR 2.96; 95% CI 1.57 to 5.55, 2 trials, 209 participants), whilst there was no evidence of a long-term effect following a brief intervention (RR 1.09; 95% CI 0.68 to 1.75, 2 trials, 341 participants). The trial of varenicline did show a significant effect on long-term smoking cessation (RR 1.45; 95% CI 1.01 to 2.07, 1 trial, 286 participants).Seven trials examined the effect of smoking intervention on postoperative complications. As with smoking outcomes, there was evidence of heterogeneity between intensive and brief behavioural interventions. In subgroup analyses there was a significant effect of intensive intervention on any complications (RR 0.42; 95% CI 0.27 to 0.65, 2 trials, 210 participants) and on wound complications (RR 0.31; 95% CI 0.16 to 0.62, 2 trials, 210 participants). For brief interventions, where the impact on smoking had been smaller, there was no evidence of a reduction in complications (RR 0.92; 95% CI 0.72 to 1.19, 4 trials, 493 participants) for any complication (RR 0.99; 95% CI 0.70 to 1.40, 3 trials, 325 participants) for wound complications. The trial of varenicline did not detect an effect on postoperative complications (RR 0.94; 95% CI 0.52 to 1.72, 1 trial, 286 participants).

AUTHORS' CONCLUSIONS

There is evidence that preoperative smoking interventions providing behavioural support and offering NRT increase short-term smoking cessation and may reduce postoperative morbidity. One trial of varenicline begun shortly before surgery has shown a benefit on long-term cessation but did not detect an effect on early abstinence or on postoperative complications. The optimal preoperative intervention intensity remains unknown. Based on indirect comparisons and evidence from two small trials, interventions that begin four to eight weeks before surgery, include weekly counselling and use NRT are more likely to have an impact on complications and on long-term smoking cessation.

Smoking is associated with an increased risk of first and recurrent ventricular tachyarrhythmias in ischemic and nonischemic patients with mild heart failure: a MADIT-CRT substudy

BACKGROUND

Limited data exist regarding the proarrhythmic effects of smoking.

OBJECTIVE

To evaluate the relationship between smoking and the risk of first and recurrent ventricular tachyarrhythmias (VTAs) in patients with mild heart failure.

METHODS

The risk of a first and recurrent appropriate implantable cardioverter-defibrillator therapy for VTAs or death was compared between nonsmokers (n = 465), past smokers (n = 780), and current smokers (n = 197) in patients with ischemic and nonischemic cardiomyopathy who were enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy study.

RESULTS

The cumulative probability of a first VTA or death was significantly higher in current smokers than in past and nonsmokers (P < .001). Multivariate analysis showed that current smokers had a significantly higher risk of first ventricular tachycardia/ventricular fibrillation or death (hazard ratio [HR] 1.51; 95% confidence interval [CI] 1.14-2.01; P = .005) and a higher risk for first ventricular tachycardia/ventricular fibrillation episode (HR 1.54, 95% CI 1.12-2.13, P = .008) than did nonsmokers. Past smokers had a risk of first VTAs or death similar to that of nonsmokers (HR 1.01; 95% CI 0.80-1.27; P = .953). In comparison to nonsmokers, the risk of recurrent VTAs was significantly higher in the total cohort of patients (HR 1.54; 95% CI 1.21-1.95; P < .001) and in the subgroups of patients with ischemic and nonischemic cardiomyopathy (HR 1.48; 95% CI 1.03-2.13; P = .035).

CONCLUSIONS

Current smokers with left ventricular dysfunction and mild heart failure are at a significantly higher risk of VTAs or death than are past smokers and nonsmokers. Smoking is associated with a significant increase in the risk of recurrent VTAs in both patients with ischemic and nonischemic cardiomyopathy.

Acute and chronic effects of smoking on myocardial function in healthy heavy smokers: a study of Doppler flow, Doppler tissue velocity, and two-dimensional speckle tracking echocardiography

BACKGROUND

The purpose of the study was to evaluate the acute and chronic effect of smoking on left ventricular function in healthy heavy smokers by conventional Doppler flow, tissue Doppler, and two-dimensional speckle tracking echocardiography (2D-STE).

METHODS

Echocardiograms were performed in 42 healthy heavy (>20 cigarettes/day) smokers (age 34 ± 5 years), before (group SM-1), 15 minutes (SM-2) and 30 minutes (SM-3) after starting smoking 2 cigarettes. Nonsmokers (n = 41, age 33 ± 4 years) served as controls. Transmitral flow, isovolumetric relaxation time (IVRT), and myocardial performance index (MPI) were measured. Tissue velocity measurements were averaged from lateral and septal mitral annulus. Longitudinal strain (GS), systolic (SRs), early diastolic (SRe), late diastolic (SRa), and isovolumetric relaxation (SRivr) strain rate were measured. The percent change in strain from end-systole to the first one-third of diastole (SI-DI = [(GS - strain at one-third diastole)/GS] × 100) was also measured.

RESULTS

IVRT and MPI were increased and early diastolic mitral annular velocity was decreased in SM-2; they returned to baseline in SM-3. There was no difference in GS and SRs. SRe and SRivr were reduced in SM-1 (P < 0.05), and remained significantly reduced in SM-2 and SM-3. SI-DI was lower in SM-1 (P = 0.011) and was further reduced in SM-2 and SM-3 (P < 0.001).

CONCLUSION

Acute and chronic smoking inhalation has adverse effects on myocardial function in healthy heavy smokers. 2D-STE is able to detect both baseline differences and late acute effects of smoking.

Interventions for preoperative smoking cessation

BACKGROUND

Smokers have a substantially increased risk of postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence, and surgery may constitute a unique opportunity for smoking cessation interventions.

OBJECTIVES

The objective of this review was to assess the effect of preoperative smoking intervention on smoking cessation at the time of surgery and 12 months postoperatively and on the incidence of postoperative complications.

SEARCH STRATEGY

The specialized register of the Cochrane Tobacco Addiction Group was searched using the free text and keywords (surgery) or (operation) or (anaesthesia) or (anesthesia). MEDLINE, EMBASE and CINAHL were also searched, combining tobacco- and surgery-related terms. Most recent search April 2010.

SELECTION CRITERIA

Randomized controlled trials that recruited people who smoked prior to surgery, offered a smoking cessation intervention, and measured preoperative and long-term abstinence from smoking and/or the incidence of postoperative complications.

DATA COLLECTION AND ANALYSIS

The authors independently assessed studies to determine eligibility. Results were discussed between the authors.

MAIN RESULTS

Eight trials enrolling a total of 1156 people met the inclusion criteria. One of these did not report cessation as an outcome. Two trials initiated multisession face to face counselling at least 6 weeks before surgery whilst six used a brief intervention. Nicotine replacement therapy (NRT) was offered or recommended to some or all participants in seven trials. Six trials detected significantly increased smoking cessation at the time of surgery, and one approached significance. Subgroup analyses showed that both intensive and brief intervention significantly increased smoking cessation at the time of surgery; pooled RR 10.76 (95% confidence interval (CI) 4.55 to 25.46, two trials) and RR 1.41 (95% CI 1.22 to 1.63, five trials) respectively. Four trials evaluating the effect on long-term smoking cessation found a significant effect; pooled RR 1.61 (95% CI 1.12 to 2.33). However, when pooling intensive and brief interventions separately, only intensive intervention retained a significant effect on long-term smoking cessation; RR 2.96 (95% CI 1.57 to 5.55, two trials).Five trials examined the effect of smoking intervention on postoperative complications. Pooled risk ratios were 0.70 (95% CI 0.56 to 0.88) for developing any complication; and 0.70 (95% CI 0.51 to 0.95) for wound complications. Exploratory subgroup analyses showed a significant effect of intensive intervention on any complications; RR 0.42 (95% CI 0.27 to 0.65) and on wound complications RR 0.31 (95% CI 0.16 to 0.62). For brief interventions the effect was not statistically significant but CIs do not rule out a clinically significant effect (RR 0.96 (95% CI 0.74 to 1.25) for any complication, RR 0.99 (95%CI 0.70 to 1.40) for wound complications).

AUTHORS' CONCLUSIONS

There is evidence that preoperative smoking interventions including NRT increase short-term smoking cessation and may reduce postoperative morbidity. The optimal preoperative intervention intensity remains unknown. Based on indirect comparisons and evidence from two small trials, interventions that begin four to eight weeks before surgery, include weekly counselling, and use NRT are more likely to have an impact on complications and on long-term smoking cessation.

Chronic cigarette smoking affects left and right ventricular long-axis function in healthy young subjects: a Doppler myocardial imaging study

OBJECTIVE

Cigarette smoking is one of the major risk factors for coronary artery disease. However, chronic smoking has additional cardiac adverse effects independent of coronary atherosclerosis. We assessed the possible effects of chronic smoking on left and right ventricular (LV, RV) long-axis function using Doppler myocardial imaging (DMI).

METHODS

Forty otherwise healthy smokers (mean age = 26+/-3 years) and 40 age-matched nonsmoking controls enrolled. Standard echocardiography protocol was followed by DMI. Peak systolic (V(S)), early (V(E)) and late diastolic (V(A)) velocities, peak systolic strain (S), and strain rate (SR) were measured from septal, lateral, and RV free walls.

RESULTS

The baseline characteristics of two groups were similar. There were significant differences regarding Doppler myocardial velocity, S, and SR indices. Septal V(E) (P < 0.04), S (P < 0.0001) and SR (P < 0.02) were significantly reduced in smokers. For both lateral and RV free wall, V(S) (P < 0.003, P < 0.002, respectively), V(E) (P < 0.0001, P < 0.002, respectively), S (P < 0.0001 for both), and SR (P < 0.0001, P < 0.002, respectively) were significantly reduced in smokers. There were significant correlations between the amount of smoking and septal, lateral, and RV free wall S and SR.

CONCLUSIONS

Chronic cigarette smoking causes alterations in long-axis systolic and diastolic functions of right and left ventricles in healthy young subjects. These changes can be accurately detected with Doppler myocardial velocity and SR imaging.

Effect of acute cigarette smoking on left and right ventricle filling parameters: a conventional and tissue Doppler echocardiographic study in healthy participants

Acute effects of smoking on left and right ventricular function is determined by conventional and tissue Doppler imaging methods in this study. Pulsed-wave Doppler indices of the left and right ventricle diastolic function, including mitral and tricuspid inflow peak early and late velocity and their ratio were obtained from 20 healthy subjects by conventional Doppler and tissue Doppler imaging. Echocardiographic indices of left and right ventricles, including isovolumetric relaxation time, deceleration time, isovolumetric contraction time, ejection time, and myocardial performance index of right ventricle were measured before and 30 minutes after smoking a cigarette. Mitral and tricuspid inflow parameters and right ventricular myocardial performance index significantly altered after smoking a cigarette. Among the tissue Doppler imaging parameters, mitral and tricuspid lateral annulus diastolic, but not systolic, velocities altered after smoking a cigarette. Acute cigarette smoking alters left and right ventricular diastolic functions in healthy nonsmokers.

Longitudinal diastolic myocardial functions are affected by chronic smoking in young healthy people: a study of color tissue Doppler imaging

AIMS

Many cardiac and hemodynamic alterations occur after acute consumption of cigarettes. The aim of this study is to evaluate the effect of chronic smoking on longitudinal myocardial functions of left ventricle in young, healthy people by using color tissue Doppler imaging modalities.

METHODS AND RESULTS

Ninety-nine healthy participants were studied. There were 65 smokers and 34 nonsmokers. All subjects were between 20 and 35 years old. Sample volumes were placed on the mid left ventricle in the inner half of the myocardium at the septum, lateral, inferior, and anterior walls. The peak systolic strain (S-S), peak systolic strain rate (S-SR), peak early diastolic SR (E-SR), peak late diastolic SR (A-SR), peak systolic tissue velocity (S-TV), peak early diastolic TV (E-TV), and peak late diastolic TV (A-TV) values were measured. For the systolic parameters S-S, S-SR, and S-TV values were not different between the groups. For the diastolic parameters smokers had lower E-SR and E-TV values than nonsmokers (P = 0.03 for both). Although there was a trend toward higher A-SR and A-TV values in the smokers, they were not reaching the statistical significance.

CONCLUSION

Chronic smoking in young, healthy people causes significant alterations in the longitudinal diastolic myocardial function parameters as assessed by color tissue Doppler imaging.

Light cigarette smoking impairs coronary microvascular functions as severely as smoking regular cigarettes

BACKGROUND

Smoking is the most prevalent and most preventable risk factor for cardiovascular diseases. Smoking low-tar, low-nicotine cigarettes (light cigarettes) would be expected to be less hazardous than smoking regular cigarettes owing to the lower nicotine and tar yield.

OBJECTIVE

To compare the chronic and acute effects of light cigarette and regular cigarette smoking on coronary flow velocity reserve (CFVR).

METHODS

20 regular cigarette smokers (mean (SD) age 24.8 (5.0)), 20 light cigarette smokers (mean age 25.6 (6.4)), and 22 non-smoker healthy volunteers (mean age 25.1 (4.2)) were included. First, each subject underwent echocardiographic examination, including CFVR measurement, after a 12 hour fasting and smokeless period. Two days later, each subject smoked two of their normal cigarettes in a closed room within 15 minutes. Finally, within 20-30 minutes, each subject underwent an echocardiographic examination, including CFVR measurement.

RESULTS

Mean (SD) CFVR values were similar in light cigarette and regular cigarette smokers and significantly lower than in the controls (2.68 (0.50), 2.65 (0.61), 3.11 (0.53), p = 0.013). Before and after smoking a paired t test showed that smoking two light cigarettes acutely decreased the CFVR from 2.68 (0.50) to 2.05 (0.43) (p = 0.001), and smoking of two regular cigarettes acutely decreased CFVR from 2.65 (0.61) to 2.18 (0.48) (p = 0.001).

CONCLUSION

Smoking low-tar, low-nicotine cigarettes impairs the CFVR as severely as smoking regular cigarettes. CFVR values are similar in light cigarette and regular cigarette smokers and significantly lower than in controls.

Chronic and acute effects of smoking on left and right ventricular relaxation in young healthy smokers

BACKGROUND

Left ventricular (LV) diastolic dysfunction has been observed in cigarette smokers with coronary artery disease. The aim of the study was to assess LV and right ventricular (RV) diastolic function in healthy, young, and slim smokers before and after smoking one cigarette.

MATERIAL AND METHODS

The participants were 66 healthy volunteers (age < 40 years; body mass index < 25 kg/m(2)): 33 smokers (study group [HS]) and 33 nonsmokers (control group). Echocardiographic examination was done in the HS before smoking one cigarette (HS-1) and after smoking one cigarette (HS-2). To assess diastolic function of LV and RV mitral valve flow (MVF), pulmonary venous flow (PVF) and tricuspid valve flow (TVF) were evaluated.

RESULTS

MVF early to late phase ratio (E/A) was significantly lower in HS-1 and HS-2 than in the control group. The PVF systolic to diastolic phase ratio (S/D) was significantly higher in HS-1 and HS-2 than in the control group. These changes suggest LV diastolic function impairment in the HS, but the MVF pattern remained within the normal range. PVF S/D showed systolic dominance (S/D > 1) typical for impaired LV relaxation and abnormal for this age group. TVF E/A was significantly lower in HS-2 than in HS-1 and control subjects and suggests RV diastolic dysfunction.

CONCLUSIONS

The following conclusion are made: (1) MVF and PVF demonstrate LV relaxation impairment in healthy smokers before and after smoking one cigarette; (2) the assessment of PVF is a good method reflecting LV diastolic function changes, even when MVF remains normal; and (3) TVF shows RV relaxation impairment after smoking one cigarette in healthy smokers.

Cigarette Smoking and the Risk of Supraventricular and Ventricular Tachyarrhythmias in High-Risk Cardiac Patients with Implantable Cardioverter Defibrillators

INTRODUCTION

Nicotine elevates serum catecholamine concentration and is therefore potentially arrhythmogenic. However, the effect of cigarette smoking on arrhythmic risk in coronary heart disease patients is not well established.

METHODS AND RESULTS

The risk of appropriate and inappropriate defibrillator therapy by smoking status was analyzed in 717 patients who received an implantable cardioverter defibrillator (ICD) in the Multicenter Automatic Defibrillator Implantation Trial-II. Compared with patients who had quit smoking before study entry (past smokers) and patients who had never smoked (never smokers), patients who continued smoking (current smokers) were significantly younger and generally had more favorable baseline clinical characteristics. Despite this, the adjusted hazard ratio (HR) for appropriate ICD therapy for fast ventricular tachycardia (at heart rates >or=180 b.p.m) or ventricular fibrillation was highest among current smokers (HR = 2.11 [95% CI 1.11-3.99]) and intermediate among past smokers (HR = 1.57 [95% CI 0.95-2.58]), as compared with never smokers (P for trend = 0.02). Current smokers also exhibited a higher risk of inappropriate ICD shocks (HR = 2.93 [95% CI 1.30-6.63]) than past (HR = 1.91 [95% CI 0.97-3.77]) and never smokers (P for trend = 0.008).

CONCLUSIONS

In patients with ischemic left ventricular dysfunction, continued cigarette smoking is associated with a significant increase in the risk of life-threatening ventricular tachyarrhythmias and inappropriate ICD shocks induced by rapid supraventricular arrhythmias. Our findings stress the importance of complete smoking cessation in this high-risk population.

Smokers are at markedly increased risk of appropriate defibrillator shocks in a primary prevention population

BACKGROUND

Cigarette smoking is a known risk factor for sudden cardiac death (SCD). It is unknown whether smoking status affects implantable cardioverter-defibrillator (ICD) therapy.

OBJECTIVE

The primary end point was appropriate ICD therapy according to smoking status.

METHODS

A total of 105 consecutive patients who underwent ICD implantation for primary prevention of SCD were retrospectively analyzed. All patients had an abnormal response to programmed ventricular stimulation performed for nonsustained ventricular tachycardia in the setting of ischemic cardiomyopathy between January 1999 and December 2003.

RESULTS

Among the 105 patients, 6 (37.5%) of 16 current smokers, 14 (25.9%) of 54 former smokers, and 2 (5.7%) of 35 of never smokers received an appropriate ICD therapy (P = .02). Kaplan-Meier analysis for survival free of appropriate ICD therapy comparing never smokers with both current smokers (P = .002) and former smokers (P = .01) demonstrated statistically significant differences by log rank over a mean follow-up of 21.8 +/- 13.7 months. Cox regression analysis found that current smoking was associated with an increased risk of appropriate therapy (hazard ratio 7.36; 95% confidence interval 1.42-38.10; P = .02) as was former smoking (hazard ratio 5.42; 95% confidence interval 1.20-24.47; P = .03). There was no difference in inappropriate therapy between groups (P = .12).

CONCLUSIONS

Cigarette smoking is an independent predictor of appropriate ICD therapy in a primary prevention population. While outcomes differences among current smokers, former smokers, and never smokers are demonstrable, the effect of smoking cessation on ICD therapy requires further study.

Interventions for preoperative smoking cessation

BACKGROUND

Smokers have a substantially increased risk of intra- and postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence. The preoperative period may be a well chosen time to offer smoking cessation interventions due to increased patient motivation.

OBJECTIVES

The objective of this review was to assess the effect of preoperative smoking intervention on smoking cessation in the postoperative period and longer term. We also set out to determine the effect of smoking cessation on the incidence of postoperative complications.

SEARCH STRATEGY

The specialized register of the Cochrane Tobacco Addiction Group was searched using the free text and keywords (surgery) OR (operation) OR (anaesthesia) or (anesthesia). MEDLINE, EMBASE and CINAHL were also searched, combining tobacco- and surgery-related terms. Most recent search February 2005.

SELECTION CRITERIA

We considered randomized trials which recruited smokers prior to surgery, offered a smoking cessation intervention, and measured abstinence from smoking in the preoperative and postoperative periods. We also considered randomized trials of the effect of smoking cessation on the incidence of intra- and postoperative complications.

DATA COLLECTION AND ANALYSIS

The authors independently assessed studies to determine eligibility. The results were discussed between the authors.

MAIN RESULTS

Four trials met the inclusion criteria. All trials significantly reduced preoperative smoking but the effect sizes were heterogeneous so a pooled effect was not estimated. Only two trials reported the effect of the smoking intervention on wound complications, and the results were heterogeneous, with a significant reduction in wound-related complications, cardiopulmonary complications and the overall risk of any complication in one trial, and no evidence of a difference in complications in the other. The effect on longer term smoking cessation was not significant in either of the two trials with follow up beyond the perioperative period.

AUTHORS' CONCLUSIONS

Preoperative smoking interventions are effective for changing smoking behaviour perioperatively. Direct evidence that reducing or stopping smoking reduces the risk of complications is based on two small trials with differing results. The impact on complications may depend on how long before surgery the smoking behaviour is changed, whether smoking is reduced or stopped completely, and the type of surgery.

Acute effects of smoking on left ventricular function and neuro-humoral responses in patients with known or suspected ischaemic heart disease

Systolic left ventricular function was examined by radionuclide ventriculography in 12 habitual smokers with known or suspected ischaemic heart disease, aged 33-69 years, before, during, and after smoking of two cigarettes in a row and was repeated on a non-smoking control day. Plasma concentrations of adrenaline, noradrenaline, renin, and angiotensin II were determined on the smoking day, before and immediately after smoking. During smoking, there were significant increases in heart rate (+27%), rate-pressure product (+23%), and cardiac output (+14%) in the face of a significant increase in left ventricular end-systolic volume (+5%) and significant decreases in ejection fraction (-6%) and stroke volume (-8%). Blood pressure was virtually unchanged, and total peripheral resistance remained constant. Plasma adrenaline increased by 100%, renin decreased by 21%, and noradrenaline and angiotensin II did not change. The humoral changes were not correlated to changes in any of the haemodynamic variables. Areas of myocardial hypokinesis emerged or widened during smoking in 11 of 12 patients. Thus, in patients with known or suspected ischaemic heart disease, smoking was associated with an acute decrease in systolic ventricular function and development of widespread hypokinesis despite adrenaline stimulation.

Acute effects of smoking on diastolic function in healthy participants: studies by conventional doppler echocardiography and doppler tissue imaging

The acute effects of smoking on left ventricular (LV) function were studied in 36 healthy participants (mean age 38 +/- 10 years). The studies were made before and immediately and 30 minutes after smoking a cigarette. From apical 4- and 2-chamber views, the mitral annular velocities, determined by pulsed wave Doppler tissue imaging, were measured at 4 LV sites corresponding to the septum and the anterior, lateral, and inferior walls. A mean value from the 4 sites was used to assess LV function. The peak systolic, early diastolic, late diastolic, and the ratio of early to late diastolic velocities were recorded. In addition, other conventional Doppler echocardiographic diastolic parameters were also determined. Heart rate was increased immediately after smoking (from 67 +/- 8 to 74 +/- 10 bpm, P <.001). There was no change in systolic mitral annular velocity. Diastolic LV function was changed significantly immediately after smoking. The transmitral A wave increased (0.55 +/- 0.1 vs 0.7 +/- 0.1 m/s, P <.001), the transmitral E/A ratio decreased (1.5 +/- 0.6 vs 1.1 +/- 0.3, P <.001), and the transmitral E-wave deceleration time increased (186 +/- 42 vs 211 +/- 44 ms, P <.05). The diastolic myocardial velocity at the mitral annulus also changed significantly: the early diastolic velocity decreased (16 +/- 3 vs 15 +/- 3 cm/s, P <.001), the late diastolic velocity increased (10.9 +/- 2.2 vs 12 +/- 2.4 cm/s, P <.001), and the ratio of early to late diastolic annular velocities decreased (1.5 +/- 0.5 vs 1.2 +/- 0.4, P <.001). The changes in the transmitral flow velocities remained unaltered even 30 minutes afterward, although the heart rate returned to normal. The results were similar in both smokers and nonsmokers. Acute smoking of a cigarette influences LV diastolic function in healthy participants. The mechanism behind this effect cannot be explained only by changes in the heart rate or loading conditions. The mechanism is probably more complex.

Interventions for preoperative smoking cessation

BACKGROUND

Smokers have a substantially increased risk of intra and postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence. The preoperative period may be a well chosen time to offer smoking cessation interventions due to increased patient motivation.

OBJECTIVES

The objective of this review was to assess the effect of preoperative smoking intervention on smoking cessation in the postoperative period and longer term. We also set out to determine the effect of smoking cessation on the incidence of postoperative complications.

SEARCH STRATEGY

The specialised register of the Tobacco Addiction Group was searched using the free text and keywords (surgery) OR (operation) OR (anaesthesia) or (anesthesia). The databases "EMBASE" and "CINAHL" were also searched, combining tobacco and surgery related terms.

SELECTION CRITERIA

We considered randomised trials which recruited smokers prior to surgery, offered a smoking cessation intervention, and measured abstinence from smoking in the pre-operative and post-operative periods. We also considered randomised trials of the effect of smoking cessation on the incidence of intra and post-operative complications.

DATA COLLECTION AND ANALYSIS

The reviewers independently assessed studies to determine eligibility. The results were discussed between the reviewers.

MAIN RESULTS

No trial meeting the inclusion criteria was found.

REVIEWER'S CONCLUSIONS

We found no evidence to determine the effectiveness of pre-operative interventions in helping people to stop smoking, or of the effectiveness of smoking cessation in reducing peri-operative complications. However, observational evidence suggests benefits in stopping smoking before surgery. Although there is no direct evidence about which interventions work best in patients preparing for surgery, behavioural and pharmacological interventions shown to be effective in other settings should be considered.

Effects of nicotine gum on coronary vasomotor responses during sympathetic stimulation in patients with coronary artery stenosis

Smoking-cessation rates may be improved by nicotine-replacement therapy that reduces withdrawal symptoms. However, nicotine may have adverse effects on coronary circulation. The purpose of this study was to examine the short-term effects of nicotine gum chewing on the dimensions of coronary arteries of patients with coronary artery disease and on the response of coronary vessels to sympathetic stimulation caused by the cold pressor test. In 17 patients who were past chronic cigarette smokers, cross-sectional areas of 32 coronary artery stenoses and 32 adjacent apparently normal segments were measured by using quantitative coronary angiography at baseline and after a cold pressor test before and after nicotine gum chewing. The cold pressor test produces an increase in arterial pressure without any change in heart rate. These changes were similar before and after nicotine gum. Before nicotine gum, the cross-sectional area of coronary stenoses and apparently normal segments was significantly and similarly reduced during the cold pressor test (-11+/-12% and -11+/-12%, respectively; both p values <0.0001 vs. baseline). After nicotine gum, baseline cross-sectional area was not modified, and response to the cold pressor test was similar to that observed before nicotine gum (-11+/-18% and -12+/-12%, respectively; both p values <0.0001 vs. baseline). In conclusion, nicotine-replacement therapy by using nicotine gum does not reduce the surface area of normal and diseased coronary segments and does not enhance the constricting effect of sympathetic stimulation produced by the cold pressor test. Thus nicotine gum may be considered a relatively safe drug in patients who need nicotine-replacement therapy to stop smoking.

Decreased blood flow but unaltered insulin sensitivity of glucose uptake in skeletal muscle of chronic smokers

Chronic cigarette smoking is associated with dysfunction of the vascular endothelium. Smokers have also been shown to be insulin-resistant, at least in some studies. Since insulin-induced vasodilation is dependent on endothelial cell nitric oxide (NO) synthesis, we tested the hypothesis that decreased skeletal muscle blood flow causes insulin resistance in smokers. We studied 37 young normotensive normolipidemic nondiabetic men, of which 14 were smokers and 23 lifelong nonsmokers. The groups were similar with respect to age, body mass index (BMI), and maximal oxygen uptake (VO2max). Basal and insulin-stimulated femoral muscle blood flow was measured using [(15)O]H2O and insulin-stimulated muscle glucose uptake using [18F]fluoro-2-deoxy-D-glucose ([18F]FDG) and positron emission tomography (PET). Whole-body glucose uptake was measured using the hyperinsulinemic (insulin infusion 5 mU/kg x min)-euglycemic clamp technique. In the basal state, muscle blood flow was 51% lower in smokers (17 +/- 3 mL/kg muscle x min) versus nonsmokers (35 +/- 17 mL/kg x min, P < .0001). Insulin increased muscle blood flow comparably in both groups; the mean rate of insulin-stimulated blood flow was 30 +/- 10 and 55 +/- 38 mL/kg x min (P = .049), respectively. Whole-body and skeletal muscle glucose uptake were similar in both groups during insulin infusion. We conclude that muscle blood flow is lower in chronic smokers compared with nonsmokers under both fasting and hyperinsulinemic conditions. The insulin-induced increase in muscle blood flow and insulin-stimulated glucose uptake appear normal, suggesting that the vasodilatory and metabolic effects of insulin are intact in smokers and the reduced muscle blood flow per se does not cause insulin resistance in these subjects.

Acute effects of nicotine content in cigarettes on coronary flow velocity and coronary flow reserve in men

We investigated the acute effects of smoking on coronary flow reserve in terms of the nicotine content of cigarettes in 21 smokers. Coronary flow velocity was measured with a Doppler flow wire. Subjects smoked cigarettes containing >1 mg nicotine (n = 8, group 1) or <1 mg (n = 6, group 2). Subjects in the control group mimicked smoking without a cigarette (n = 7). Coronary flow reserve decreased after smoking in group 1, but not in group 2 or the control group. This reduction may have mediated nicotine or some other unknown substances influenced by smoking.

Cardiovascular toxicity of nicotine: implications for nicotine replacement therapy

This review discusses the known cardiovascular effects of smoking and the effects of nicotine without tobacco smoke and interprets the available data on cardiovascular risk during nicotine replacement therapy (NRT). Nicotine gum and patches are now approved for over the counter sale in the United States. Smokers with cardiovascular disease are advised to seek physician counseling before using nicotine products, but information regarding the safety of these products in such patients is not readily available to most physicians. Nicotine may contribute to cardiovascular disease, presumably by hemodynamic consequences of sympathetic neural stimulation and systemic catecholamine release. However, there are many potential cardiovascular toxins in cigarette smoke other than nicotine. The doses of nicotine obtained by regular cigarette smoking generally exceed those delivered by NRTs, and the cardiovascular effects of nicotine are, in general, more intense when delivered rapidly by cigarette smoking than the slower delivery by transdermal nicotine or nicotine gum. Because the dose-cardiovascular response relation for nicotine is flat, the effects of cigarette smoking in conjunction with NRT are similar to those of cigarette smoking alone. Cigarette smoking increases blood coagulability, a major risk factor for acute cardiovascular events, whereas transdermal nicotine does not appear to do so. Clinical trials of NRT in patients with underlying, stable coronary disease suggest that nicotine does not increase cardiovascular risk. At worst, the risks of NRT are no more than those of cigarette smoking. The risks of NRT for smokers, even for those with underlying cardiovascular disease, are small and are substantially outweighed by the potential benefits of smoking cessation.

Nicotine and sympathetic neurotransmission

Nicotine increases heart rate, myocardial contractility, and blood pressure. These nicotine-induced cardiovascular effects are mainly due to stimulation of sympathetic neurotransmission, as nicotine stimulates catecholamine release by an activation of nicotine acetylcholine receptors localized on peripheral postganglionic sympathetic nerve endings and the adrenal medulla. The nicotinic acetylcholine receptor is a ligand-gated cation channel with a pentameric structure and a central pore with a cation gate, which is essential for ion selectivity and permeability. Binding of nicotine to its extracellular binding site leads to a conformational change of the central pore, which results in the influx of sodium and calcium ions. The resulting depolarization of the sympathetic nerve ending stimulates calcium influx through voltage-dependent N-type calcium channels, which triggers the nicotine-evoked exocytotic catecholamine release. In the isolated perfused guinea-pig heart, cardiac energy depletion sensitizes cardiac sympathetic nerves to the norepinephrine-releasing effect of nicotine, as indicated by a leftward shift of the concentration-response curve, a potentiation of maximum transmitter release, and a delay of the tachyphylaxis of nicotine-evoked catecholamine release. This sensitization was also shown to occur in the human heart under in vitro conditions. Through the intracardiac release of norepinephrine, nicotine induces a beta-adrenoceptor-mediated increase in heart rate and contractility, and an alpha-adrenoceptor-mediated increase in coronary vasomotor tone. The resulting simultaneous increase in oxygen demand and coronary resistance has a detrimental effect on the oxygen balance of the heart, especially in patients with coronary artery disease. Sensitization of the ischemic heart to the norepinephrine-releasing effect of nicotine may be a trigger for acute cardiovascular events in humans, such as acute myocardial infarction and/or life-threatening ventricular tachyarrhythmias.

Effects of cigarette smoking on the angiographic evolution of coronary atherosclerosis. A Canadian Coronary Atherosclerosis Intervention Trial (CCAIT) Substudy. CCAIT Study Group

BACKGROUND

Although smoking increases both the risk of developing coronary disease and the risk of coronary events in patients with known coronary atherosclerosis, the effect of smoking on the evolution of coronary atherosclerosis as assessed by serial angiography is poorly defined.

METHODS AND RESULTS

Ninety smokers with coronary atherosclerosis shown on a recent angiogram and with fasting cholesterol levels between 220 and 300 mg/dL were enrolled in a randomized, double-blind, placebo-controlled trial of cholesterol-lowering therapy, along with 241 nonsmokers and exsmokers. Lovastatin at a mean dose of 36 mg/d lowered total and LDL cholesterol by 21 +/- 11% and 29 +/- 11%, respectively, but these levels changed by < 2% in placebo-treated patients. Coronary arteriography was repeated after 2 years in 72 smokers and their 557 lesions were measured blindly with an automated quantitative system, along with 1752 lesions in 227 nonsmokers. Coronary change score, the per-patient mean of the minimal lumen diameter changes for all qualifying lesions, worsened by 0.16 +/- 0.16 mm in smokers and by 0.07 +/- 0.15 mm in nonsmokers in the placebo group (P < .001). Lovastatin-treated smokers had less worsening (0.07 +/- 0.15 mm) than placebo-treated smokers (P = .024). One or more coronary lesions progressed in 16 of 34 lovastatin-treated smokers and in 28 of 38 placebo-treated smokers (47% versus 74%, P < .001). In the placebo group, new coronary lesions developed in 21 of 38 smokers and in 28 of 115 nonsmokers (55% versus 24%, P < .001); fewer lovastatin-treated smokers developed new lesions (15% versus 55%, P < .001).

CONCLUSIONS

Smoking accelerates coronary progression and new lesion formation as assessed by serial quantitative coronary arteriography. Lovastatin slows the progression of coronary atherosclerosis and prevents the development of new coronary lesions in smokers.

How smoking affects blood pressure

The addictive effects of smoking are only partly known, but it is likely that hemodynamic effects of tobacco smoking may contribute to the habituation. It has since long been known that blood pressure and heart rate increase during smoking. These effects are specifically associated with nicotine while the other components of which more than a thousand have been isolated seem to be of minor importance. The rise in blood pressure is due both to an increase in cardiac output and total peripheral vascular resistance. The blood pressure rise appears immediately and occurs before any increase in circulating catecholamines. In hypertensive patients the blood pressure lowering effect of beta-blockers may be partly abolished by tobacco smoking whereas alpha-receptor blockers seem to maintain the antihypertensive efficacy in smokers. It is a paradox that while smoking acutely increases blood pressure, a slightly lower blood pressure level has been found among smokers than nonsmokers in larger epidemiological studies. Because blood pressure may increase after cessation of smoking, a smoke quitting program should not postpone initiation of antihypertensive treatment in patients otherwise in need of such treatment.

Smoking cessation and arrhythmic death: the CAST experience. The Cardiac Arrhythmia Suppression Trial (CAST) Investigators

OBJECTIVES

This study was performed to assess the effect of cigarette smoking cessation on overall mortality and the incidence of arrhythmic death in the population of the Cardiac Arrhythmia Suppression Trial (CAST).

BACKGROUND

Cigarette smoking is a known risk factor for sudden cardiac death. Some of the adverse effects of smoking have been shown to dissipate with smoking cessation, but the time frame over which these changes occur and the population that stands to benefit have not been well delineated. CAST was a multicenter double-blind placebo-controlled study to determine whether suppression of ventricular ectopic activity by means of antiarrhythmic drugs in patients with left ventricular dysfunction after acute myocardial infarction would reduce the incidence of arrhythmic death.

METHODS

Of 2,752 patients randomized to blinded therapy, 1,026 were smoking at the time of their baseline examination and completed a 4-month follow-up visit. Of these, 517 stopped smoking by the time of this visit ("quitters") and 509 continued to smoke ("smokers").

RESULTS

Over a mean follow-up period of slightly < 16 months, there were 17 arrhythmic deaths and 32 total deaths among the quitters versus 30 and 45, respectively, among the smokers; these differences were of marginal statistical significance. Most of the fatal events occurred in a group at high risk of ongoing ischemia: the 558 patients who did not have thrombolysis or undergo revascularization after their qualifying myocardial infarction. In this high risk cohort, smoking cessation greatly reduced the incidence of arrhythmic death and was associated with a statistically significant benefit in survival.

CONCLUSIONS

Smoking cessation was accompanied by a marked reduction in arrhythmic death and overall mortality that achieved statistical significance in a high risk cohort. These data imply that smoking cessation is important in risk factor reduction in patients with advanced ischemic heart disease.

Effect of acute and long-term smoking on myocardial blood flow and flow reserve

BACKGROUND

Cigarette smoking is a major preventable risk factor for coronary artery disease and sudden cardiac death. However, the effect of acute and long-term cigarette smoking on coronary vasodilatory capacity and myocardial flow reserve has not been quantified in humans.

METHODS AND RESULTS

To examine the effect of short-term and long-term smoking, myocardial blood flow was quantified at rest and during dipyridamole-induced hyperemia (0.56 mg/kg) in 12 smokers (10 males and 2 females; mean age, 27 +/- 4 years) under baseline conditions (reflecting the effect of long-term smoking) and during short-term cigarette smoking with 13N ammonia, positron emission tomography, and a two-compartment model. Twelve sex- and age-matched nonsmokers served as control subjects. Smoking significantly increased the rate-pressure product at rest from 7525 +/- 1290 to 9160 +/- 1125 (P < .001 versus baseline), which was paralleled by a proportional increase in myocardial blood flow at rest (0.70 +/- 0.17 versus 0.88 +/- 0.17 mL.g-1.min-1; P < .05 versus baseline). In contrast, hyperemic blood flow declined from 2.23 +/- 0.35 at baseline (P = NS versus control) to 1.98 +/- 0.32 mL.g-1.min-1 during smoking (P < .01 versus baseline). Accordingly, the myocardial flow reserve declined from 3.36 +/- 0.83 in smokers at baseline to only 2.28 +/- 0.28 during smoking (P < .0001 versus baseline). Thus, myocardial blood flow and flow reserve were similar in young, long-term smokers and young, healthy nonsmokers.

CONCLUSIONS

Short-term smoking increases the coronary vasomotor tone during dipyridamole-induced hyperemia and markedly reduces the myocardial flow reserve. In contrast, long-term smoking does not attenuate the coronary vasodilatory capacity in young individuals with a relatively short smoking history. It might be speculated that the short-term reduction in the coronary vasodilatory capacity during smoking could lower the ischemic threshold in smokers with coronary artery disease and contribute to the increased risk for sudden cardiac death.

Coronary-artery vasoconstriction induced by cocaine, cigarette smoking, or both

BACKGROUND

In humans, the use of cocaine and cigarette smoking each increase the heart's metabolic need for oxygen but may also decrease the supply of oxygen. As cocaine abuse has proliferated, cocaine-associated chest pain, myocardial infarction, and sudden death have occurred, especially among smokers. We assessed the influence of intranasal cocaine and cigarette smoking, alone and together, on myocardial oxygen demand and coronary arterial dimensions in subjects with and subjects without coronary atherosclerosis.

METHODS

In 42 smokers (28 men and 14 women; age, 34 to 79 years; 36 with angiographically demonstrable coronary artery disease), we measured the product of the heart rate and systolic arterial pressure (rate-pressure product) and coronary arterial diameters before and after intranasal cocaine at a dose of 2 mg per kilogram of body weight (n = 6), one cigarette (n = 12), or intranasal cocaine at a dose of 2 mg per kilogram followed by one cigarette (n = 24).

RESULTS

No patient had chest pain or ischemic electrocardiographic changes after cocaine use or smoking. The mean (+/- SE) rate-pressure product increased by 11 +/- 2 percent after cocaine use (n = 30, P < 0.001), by 12 +/- 4 percent after one cigarette (n = 12, P = 0.021), and by 45 +/- 5 percent after both cocaine use and smoking (n = 24, P < 0.001). As compared with base-line measurements, the diameters of nondiseased coronary arterial segments decreased on average by 7 +/- 1 percent after cocaine use (P < 0.001), by 7 +/- 1 percent after smoking (P < 0.001), and by 6 +/- 2 percent after cocaine use and smoking (P < 0.001). The diameters of diseased segments decreased by 9 +/- 2 percent after cocaine use (n = 18, P < 0.001), by 5 +/- 5 percent after smoking (n = 12, P = 0.322), and by 19 +/- 4 percent after cocaine use and smoking (n = 12, P < 0.001). The increase in the rate-pressure product and the decrease in the diameters of diseased segments caused by cocaine use and smoking together were greater (P < 0.001 and P = 0.037, respectively) than the changes caused by either alone.

CONCLUSIONS

The deleterious effects of cocaine on myocardial oxygen supply and demand are exacerbated by concomitant cigarette smoking. This combination substantially increases the metabolic requirement of the heart for oxygen but simultaneously decreases the diameter of diseased coronary arterial segments.

Acute effect of cigarette smoking on the coronary circulation: constriction of epicardial and resistance vessels

OBJECTIVES

This study was performed to determine the acute effect of cigarette smoking on proximal and distal epicardial conduit and coronary resistance vessels.

BACKGROUND

Cigarette smoking causes constriction of epicardial arteries and a decrease in coronary blood flow in patients with coronary artery disease, despite an increase in myocardial oxygen demand. The role of changes in resistance vessel tone in the acute coronary hemodynamic effect of smoking has not been examined.

METHODS

Twenty-four long-term smokers were studied during cardiac catheterization after vasoactive medications had been discontinued. The effect of smoking one cigarette 10 to 15 mm long on proximal and distal conduit vessel segments was assessed before and immediately after smoking and at 5, 15 and 30 min after smoking (n = 8). To determine the effect of smoking on resistance vessels, coronary flow velocity was measured in a nonobstructed artery with a 3F intracoronary Doppler catheter before and for 5 min after smoking (n = 8). Eight patients were studied without smoking to control for spontaneous changes in conduit arterial diameter (n = 5) and resistance vessel tone (n = 3).

RESULTS

The average diameter of proximal coronary artery segments decreased from 2.56 +/- 0.12 mm (mean +/- SEM) before smoking to 2.41 +/- 0.09 mm 5 min after smoking (-5 +/- 2%, p < 0.05). Distal coronary diameter decreased from 1.51 +/- 0.07 to 1.39 +/- 0.06 mm (-8 +/- 2%, p < 0.01). Marked focal vasoconstriction after smoking was observed in two patients. Coronary diameter returned to baseline by 30 min after smoking. There was no change in vessel diameter in control patients. Despite a significant increase in the heart rate-mean arterial pressure product, coronary flow velocity decreased by 7 +/- 4% (p < 0.05) and coronary vascular resistance increased by 21 +/- 4% (p < 0.01) 5 min after smoking. There was no change in these variables in the control subjects.

CONCLUSIONS

Smoking causes immediate constriction of proximal and distal epicardial coronary arteries and an increase in coronary resistance vessel tone, despite an increase in myocardial oxygen demand. These acute coronary hemodynamic effects may contribute to the adverse cardiovascular consequences of cigarette smoking.

Acetylcholine-induced coronary vasoconstriction in young, heavy smokers with normal coronary arteriographic findings

PURPOSE

Cigarette smoking is a major coronary risk factor. Acetylcholine dilates coronary arteries in normal subjects, but acetylcholine-induced coronary constriction has been reported in patients with normal coronary arteriographic findings and other risk factors for coronary artery disease. The purpose of the present study was to evaluate the epicardial coronary artery response to acetylcholine in young, heavy smokers.

SUBJECTS AND METHODS

Responses to stepwise infusion of acetylcholine (10(-8)M, 10(-7)M, 10(-6)M, and 10(-5)M) into the left coronary artery were studied in five young, heavy smokers and in five age-matched nonsmokers. All subjects were normotensive and had normal left ventricular function and coronary arteriographic findings. Levels of serum cholesterol, triglycerides, and low-density lipoprotein levels were within normal ranges. Vessel dimensions were measured on four different segments in each subject, with quantitative digital-substracted arteriography.

RESULTS

In smokers, no change was produced at the 10(-8) M and 10(-7) M concentrations of acetylcholine, but progressive diameter reduction was observed at 10(-6) M and 10(-5) M acetylcholine (-26.6% +/- 13.6%, p < 0.001; -42.2% +/- 9.5%, p < 0.001, respectively). In nonsmokers, a progressive diameter dilation was produced from 10(-8) M to 10(-6) M acetylcholine (+5.3% +/- 3.6%, p < 0.001; +12.4% +/- 6.5%, p < 0.001; +15.9% +/- 6.9%, p < 0.001, respectively), and no change was observed at 10(-5) M acetylcholine. In the two groups, all segments dilated after infusion of intracoronary isosorbide dinitrate.

CONCLUSION

The abnormal coronary vasoconstriction induced by acetylcholine in young, heavy smokers with angiographically normal coronary arteries suggests an endothelial vasodilator dysfunction. This mechanism may contribute to the pathogenesis of coronary artery disease in cigarette smokers.

Arterial blood nicotine concentration and coronary vasoconstrictive effect of low-nicotine cigarette smoking

Low-nicotine cigarettes have been advertised to the public as less harmful to the cardiovascular system. We studied the effects of smoking two low-nicotine cigarettes on arterial and venous blood nicotine levels, hemodynamics, and coronary vascular tone in 12 patients referred for diagnostic coronary arteriography. All were chronic smokers as evidenced by their elevated baseline arterial and venous cotinine blood levels (139 +/- 30 ng/ml and 155 +/- 34 ng/ml, respectively). High-resolution coronary angiograms were evaluated "blindly" before and after smoking. An electronic caliper was used to measure the diameter of disease-free coronary segments of the left anterior descending and circumflex arteries. Arterial nicotine levels rose from 5 +/- 1 ng/ml at baseline to 37 +/- 7 ng/ml (p less than 0.01) after the first cigarette was smoked and to 45 +/- 8 ng/ml (p less than 0.01) after the second cigarette. Venous nicotine levels rose from 8 +/- 2 ng at baseline to 15 +/- 3 ng/ml (p less than 0.05) after the first cigarette and to 20 +/- 3 ng/ml (p less than 0.01) after the second cigarette. After the first cigarette heart rate increased 8 +/- 2 beats/min (p less than 0.003) and double product 1229 +/- 400 beats/min x mm Hg (p less than 0.02). Compared to baseline values, after the second cigarette heart rate increased 9 +/- 1 beats/min (p less than 0.001) and double product 1767 +/- 486 beats/min x mm Hg (p less than 0.01). Systolic, diastolic, and mean blood pressure did not change significantly after either the first or second cigarette.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary heart disease, cancer and mortality in male middle-aged light smokers

We examined the effect of light smoking in relation to incidence of coronary heart disease (CHD) in a general population sample consisting of 6879 men aged 47-55 years and free of previous myocardial infarction (MI) at baseline. After a follow-up of mean duration 11.8 years, 11.0% of men smoking 1-4 cigarettes daily (n = 228) had suffered a major CHD event, compared to 3.7% of non-smokers (n = 2049) [adjusted odds ratio 2.8 (1.7-4.7)]. No further increase in risk was observed in men who smoked more. There was an increasing risk of death from cancer with the number of cigarettes smoked per day. Mortality was increased in all categories of cigarette smokers, particularly among the very heavy smokers, who had a mortality risk of 22% compared to 6% among nonsmokers [adjusted odds ratio 4.4 (2.7-7.1)]. Data from an examination 4 years later considered only those men who stated that their smoking habits were identical on both occasions (n = 3981). Among these subjects the incidence of CHD after a mean period of 7.1 years was 10.6% in men smoking 1-4 cigarettes per day, compared to 2.6% in nonsmokers [adjusted O.R. 4.6 (2.1-10.1)]. No dose-response effect was observed. Even very light cigarette smoking considerably increases the risk of CHD in middle-aged men.

Changes of diastolic function induced by cigarette smoking: an echocardiographic study in patients with coronary artery disease

In 28 chronic smokers (11 women, 17 men, 53 +/- 10 years old) with coronary artery disease (greater than 75% stenosis), left ventricular (LV) relaxation and filling behavior was assessed before and after inhalation of 0.9 mg nicotine (1 cigarette) by echocardiography. The following acute nicotine-mediated changes were noted (one-sided Wilcoxon test): heart rate increased from 67 to 81 beats/min (p greater than .001); the early diastolic flow (E wave) integral decreased from 49 to 39 mm (p less than .001); the late diastolic flow integral (A wave) increased from 36 to 41 mm (p less than .01). Consecutively, the ratio between E and A wave flow integrals decreased from 1.4 to 0.9 (p less than .001); the atrial contribution to LV filling rose from 42 to 53% (p less than .001); and the isovolumetric relaxation period increased from 89 to 122 ms (p less than .001). In cigarette smokers with coronary artery disease acute administration of nicotine hence causes a shift of mitral blood flow from early (E wave) to late (A wave) diastole and a prolongation of the isovolumetric relaxation time. Thus, cigarette smoking significantly affects LV diastolic function independently of its role as a risk factor for coronary atherosclerosis.

Perioperative smoking cessation and anesthesia: a review

Perioperative smoking causes acute changes in cardiopulmonary function that can have unfavorable implications for patients undergoing anesthesia. These cardiopulmonary effects are carbon monoxide and nicotine mediated changes in oxygen (O2) delivery and myocardial O2 balance. Smokers also are at increased risk for postoperative pulmonary complications that are secondary to chronic changes in lung function. Smoking-induced acute changes in cardiopulmonary function can be largely avoided by a brief period of preoperative smoking abstinence. Bringing about a decrease in postoperative pulmonary complications requires a much longer period of preoperative abstinence. Because the perioperative period is in many ways an ideal time to abandon the smoking habit permanently, anesthesiologists, in cooperation with other health professionals, can perhaps play a more active role in facilitating this process.