Implications of cigarette smoking for the management of patients with acute coronary syndromes

Tobacco use disorder and cardiovascular health

This narrative review examines the impact of cigarette smoking and the use of other tobacco and nicotine products on cardiovascular disease. Smoking increases the incidence of both acute and chronic cardiovascular diseases, and the harmful effects are substantially and relatively quickly reversible after quitting. Recommended cessation treatment includes offering pharmacotherapy, counseling which should emphasize the rapid risk reduction that occurs after quitting and adequate follow-up contacts. Although most research on cardiovascular disease in relation to tobacco use has focused upon cigarette smoking, we also review available data related to other combustible tobacco products, smokeless tobacco, electronic nicotine delivery systems and second-hand smoke. We discuss the implications of smoking on clinical management of patients with heart disease and newer developments with potential relevance to treatment of such patients.

Coronary heart disease and heart failure in asthma, COPD and asthma-COPD overlap

INTRODUCTION

We investigated risk of coronary heart disease and heart failure in phenotypes of obstructive airway disease.

METHODS

Among 91 692 participants in the Copenhagen General Population Study, 42 058 individuals were classified with no respiratory disease, and 11 988 individuals had different phenotypes of obstructive airways disease: asthma with early onset or late-onset, chronic obstructive pulmonary disease (COPD) with forced expiratory volume in one second (FEV₁) above or below 50% of predicted value (%p) or asthma-COPD overlap (ACO).

RESULTS

During a mean follow-up of 5.7 years we registered 3584 admissions for coronary heart disease and 1590 admissions for heart failure. Multivariable Cox regression analyses of time to first admission were used with a two-sided p value of 0.05 as significance level. Compared with no respiratory disease the highest risks of coronary heart disease and heart failure were observed in ACO with late-onset asthma and FEV₁ <50% p, HR=2.2 (95% CI 1.6 to 3.0), and HR=2.9 (95% CI 2.0 to 4.3), respectively. In COPD with FEV₁ above 50% p the HRs were 1.3 (95% CI 1.2 to 1.5) for coronary heart disease and 1.9 (95% CI 1.6 to 2.3) for heart failure. Asthma associated with increased risks of coronary heart disease and heart failure, however, in asthma without allergy the HR was 1.1 (95% CI 0.7 to 1.6) for coronary heart disease while individuals with allergy had an HR of 1.4 (95% CI 1.1 to 1.6).

CONCLUSIONS

Risks of coronary heart disease and heart failure were increased in asthma, COPD and ACO. In asthma, the risk of coronary heart disease depended on presence of allergy. We suggest that cardiovascular risk factors should be assessed systematically in individuals with obstructive airway disease with the potential to facilitate targeted treatments.

Stabilisation of atherosclerotic plaques

Plaque rupture and subsequent thrombotic occlusion of the coronary artery account for as many as three quarters of myocardial infarctions. The concept of plaque stabilisation emerged about 20 years ago to explain the discrepancy between the reduction of cardiovascular events in patients receiving lipid lowering therapy and the small decrease seen in angiographic evaluation of atherosclerosis. Since then, the concept of a vulnerable plaque has received a lot of attention in basic and clinical research leading to a better understanding of the pathophysiology of the vulnerable plaque and acute coronary syndromes. From pathological and clinical observations, plaques that have recently ruptured have thin fibrous caps, large lipid cores, exhibit outward remodelling and invasion by vasa vasorum. Ruptured plaques are also focally inflamed and this may be a common denominator of the other pathological features. Plaques with similar characteristics, but which have not yet ruptured, are believed to be vulnerable to rupture. Experimental studies strongly support the validity of anti-inflammatory approaches to promote plaque stability. Unfortunately, reliable non-invasive methods for imaging and detection of such plaques are not yet readily available. There is a strong biological basis and supportive clinical evidence that low-density lipoprotein lowering with statins is useful for the stabilisation of vulnerable plaques. There is also some clinical evidence for the usefulness of antiplatelet agents, beta blockers and renin-angiotensin-aldosterone system inhibitors for plaque stabilisation. Determining the causes of plaque rupture and designing diagnostics and interventions to prevent them are urgent priorities for current basic and clinical research in cardiovascular area.

Cardiovascular effects of electronic cigarettes

Cardiovascular safety is an important consideration in the debate on the benefits versus the risks of electronic cigarette (EC) use. EC emissions that might have adverse effects on cardiovascular health include nicotine, oxidants, aldehydes, particulates, and flavourants. To date, most of the cardiovascular effects of ECs demonstrated in humans are consistent with the known effects of nicotine. Pharmacological and toxicological studies support the biological plausibility that nicotine contributes to acute cardiovascular events and accelerated atherogenesis. However, epidemiological studies assessing Swedish smokeless tobacco, which exposes users to nicotine without combustion products, generally have not found an increased risk of myocardial infarction or stroke among users, but suggest that nicotine might contribute to acute cardiovascular events, especially in those with underlying coronary heart disease. The effects of aldehydes, particulates, and flavourants derived from ECs on cardiovascular health have not been determined. Although ECs might pose some cardiovascular risk to users, particularly those with existing cardiovascular disease, the risk is thought to be less than that of cigarette smoking based on qualitative and quantitative comparisons of EC aerosol versus cigarette smoke constituents. The adoption of ECs rather than cigarette smoking might, therefore, result in an overall benefit for public health.

Cardiovascular risks associated with smoking: a review for clinicians

The cardiovascular consequences of cigarette smoking may not be as readily recognized as the adverse respiratory consequences. Smoking results in sudden death, myocardial infarction, coronary heart disease, worsened outcomes after angioplasty or bypass surgery, cerebrovascular disease, aortic aneurysm, peripheral vascular disease, increased risk of complications of hypertension and impotence. Physicians should encourage and help all their smoking patients to quit. Pharmacotherapy for smoking cessation is one of the most cost-effective healthcare interventions and should be offered to all dependent smokers. Both nicotine replacement and bupropion have been shown to be well tolerated in populations with cardiovascular disease.

Change in left ventricular systolic function in patients with ST elevation myocardial infarction: Evidence for smoker's paradox or pseudo-paradox?

Background

The ‘smoker's paradox’ refers to the observation of favorable prognosis in current smokers following an acute ST elevation myocardial infarction (STEMI) in the era of fibrinolysis, however, several STEMI studies have demonstrated conflicting results in patients undergoing primary percutaneous coronary intervention (p-PCI).

Objective

Aim of the current study was to evaluate the impact of cigarette smoking on left ventricular function in STEMI patients undergoing p-PCI.

Methods

Our population is represented by 74 first-time anterior STEMI patients undergoing p-PCI, 37 of whom were smokers. We assessed left ventricular function by left ventricular ejection fraction (LVEF) on the second day after admission and at 3-month follow-up. Early predictors of adverse left ventricular remodelling after STEMI treated by p-PCI were examined.

Results

Basal demographics and comorbidities were similar between groups. Although the LVEF during the early phase was higher in smokers compared to non-smokers (44.95 ± 7.93% vs. 40.32 ± 7.28%; p = 0.011); it worsened in smokers at follow-up (mean decrease in LVEF: −2.70 ± 5.95%), whereas it improved in non-smokers (mean recovery of LVEF: +2.97 ± 8.45%). In univariate analysis, diabetes mellitus, peak troponin I, current smoking, and lower TIMI flow grade after p-PCI, pain-to-door time and door-to-balloon times were predictors of adverse left ventricular remodelling. After multivariate logistic regression analysis, smoking at admission, lower TIMI flow grade after p-PCI, the pain-to-door time and door-to-balloon times remained independent predictors of deterioration in LVEF.

Conclusion

True or persistent ‘smoker's paradox’ does not appear to be relevant among STEMI patients undergoing p-PCI. The ‘smoker's paradox’ is in fact a pseudo-paradox. Further studies with larger numbers may be warranted.

Impact of smoking on the outcome of patients treated with drug-eluting stents: 1-year results from the prospective multicentre German Drug-Eluting Stent Registry (DES.DE)

BACKGROUND

Cigarette smoking strongly increases morbidity and mortality from cardiovascular causes, but the relevance of smoking in patients treated with drug-eluting stents (DES) is unknown.

AIMS

To assess the impact of smoking on the presentation and outcome of patients treated with DES.

METHODS AND RESULTS

We analyzed data from the prospective multicentre German Drug-Eluting Stent Registry (DES.DE) and identified 1,122 patients who had never smoked and 1,052 patients who were current smokers. Smokers were younger (56.5 vs. 69.4 years, p < 0.0001), more often males, with less frequent diabetes and hypertension compared to non-smokers. Smokers presented more often with acute coronary syndromes. After a mean follow-up of 12.5 months, smokers had both higher mortality (4.6 vs. 2.7%, p < 0.05) and myocardial infarction (MI) rates (4.9 vs. 3%, p < 0.01). There was no significant difference between smokers and non-smokers in the rate of target vessel revascularization (9.8 vs. 11.4%, p = 0.26). Major adverse cardiac and cerebrovascular events (defined as the composite of death, MI and stroke, MACCE) were higher in smokers (10.6 vs. 6.1%, p < 0.001). Moreover, after adjustment for baseline clinical and angiographic variables, smoking continued to be a strong independent predictor for MACCE (OR = 2.34, 95% CI 1.49-3.68). In a subgroup analysis, we found that the increased risk of smoking was most prominent in patients presenting with stable angina pectoris (OR = 3.71, 95% CI 1.24-2.57, p < 0.05). Smoking almost doubled the risk for MACCE in acute MI patients, though this did not reach statistical significance (adjusted OR = 1.91, 95% CI 0.93-3.94, p = 0.74).

CONCLUSION

This large multicentre DES registry provides evidence that smokers treated with DES, despite lower incidence of predisposing risk factors for atherosclerosis, experience higher rates of death and MI compared to non-smokers, particularly in the setting of stable coronary artery disease. Smoking has only marginal effects on target vessel revascularization rates in patients treated with DES.

Magnitude of change in cardiac health-enhancing behaviours 6 months following an acute myocardial infarction

BACKGROUND

The adoption of health-enhancing behaviours is essential to reduce the likelihood of recurrent coronary events.

AIMS

This study assessed the magnitude of health behaviour change 6 months following a first acute myocardial infarction (AMI), and examined differences between cardiac rehabilitation attendees and non-attendees.

METHODS

One hundred and six first AMI patients (males n=76, Australian-born n=71) participated in a 6-month follow-up of a descriptive longitudinal survey. Data on non-smoking behaviour, weight normalisation, adequate physical activity, low dietary fat intake, medication adherence and cardiac rehabilitation attendance were collected. The magnitude of change in health-enhancing behaviours from baseline to follow-up was calculated.

RESULTS

Whilst there was an overall increase in health-enhancing behaviours at the 6-month follow-up (P<0.001), nonsmoking behaviour, low dietary fat intake and medication adherence were more likely to be achieved than adequate physical activity and weight normalisation. Attendees at cardiac rehabilitation were more likely to report positive lifestyle change (P=0.001) and feeling healthier (P=0.040) than non-attendees.

CONCLUSION

The wide variation in the adoption of health-enhancing behaviours at the 6-month follow-up suggested that participants were selective about which behaviours they changed. Cardiac rehabilitation personnel need to emphasise the importance of undertaking all health-enhancing behaviours in order to maximise their multiplicative benefits.

Coronary collateral circulation: the effects of smoking and alcohol

OBJECTIVE

The presence or absence of coronary collaterals is of vital importance during acute ischemia. Smoking and alcohol have been suggested to play a role, but data are scarce. We examined the extent to which smoking and alcohol use affect the presence of coronary collateral circulation.

METHODS

Cross-sectional study in 242 patients, admitted for elective PTCA. Smoking was defined as past or current. Pack years were calculated and categorized into never-smokers (reference-category): <10, 10-19, 20-29, and >or=30 pack years. Alcohol consumption was defined as past or current, and categorized into never-users (reference-category): <1, 1-10, 11-20, and >or=21 units per week (UPW). Collaterals were graded with Rentrop's classification. Coronary collateral presence was defined as Rentrop-grade >or=1.

RESULTS

Current smoking (odds ratio (OR) 4.17; 95% confidence interval (CI) 1.79-9.71) was positively associated, while pack years of smoking was not related. Current alcohol intake showed a J-shaped tendency with coronary collateral presence, while past moderate alcohol consumption was inversely associated (OR 0.19; 95% CI 0.04-0.98).

CONCLUSIONS

Smoking and (to some extent) alcohol use are associated with collateral presence. The results support the view that life-style factors may affect the formation of coronary collaterals in patients with ischemic cardiac disease.

Hereditary C2 deficiency in Sweden: frequent occurrence of invasive infection, atherosclerosis, and rheumatic disease

Although frequently asymptomatic, homozygous C2 deficiency (C2D) is known to be associated with severe infections and rheumatic disease. We describe the clinical findings in 40 persons with C2D from 33 families identified in Sweden over 25 years. Medical records covering 96% of the accumulated person-years were reviewed, giving a mean observation time of 39 years (range, 1-77 yr). Severe infection was the predominant clinical manifestation in the cohort: 23 patients had a past history of invasive infections, mainly septicemia or meningitis caused by Streptococcus pneumoniae, and 12 patients had repeated infections of this kind. Nineteen patients had at least 1 episode of pneumonia, and recurrent pneumonia was documented in 10 patients. Repeated infections occurred mainly during infancy and childhood. Systemic lupus erythematosus was found in 10 patients. Another 7 patients had undifferentiated connective tissue disease (n = 4) or vasculitis (n = 3). We found no correlation between susceptibility to invasive infection and rheumatologic disease. Cardiovascular disease occurred at a high rate, with a total of 10 acute myocardial infarctions and 5 cerebrovascular episodes in 6 patients. Causes of death among the C2D patients were infection (n = 5), acute myocardial infarction (n = 3), and cancer (n = 1). We suggest that severe infection may be the principal clinical manifestation of C2D. We also provide novel evidence for a possible role of C2D in the development of atherosclerosis consistent with findings in mannan-binding deficiency and experimental C3 deficiency. In addition, we confirm the well-known association between C2D and systemic lupus erythematosus.

Changes of brain endothelin levels and peripheral endothelin receptors by chronic cigarette smoke in spontaneously hypertensive rats

The present study was conducted to evaluate the contribution of endothelin (ET) to the pharmacodynamic response to chronic cigarette smoke in spontaneously hypertensive rats (SHR). The contribution of ET was studied consequent to the hemodynamic response following 8 weeks of cigarette smoke by determining the changes in tissue ET-1 content and ET receptors. The blood pressure (BP) at the early phase of smoking and the heart rate (HR) 24 h later were apparently reduced in SHR, while the HR at the early phase was transiently elevated in normotensive Wistar Kyoto (WKY) rats. Tissue ET-1 levels in the hypothalamus, striatum, and cortex of SHR were higher than those in WKY rats, and these higher levels in SHR were reduced by exposure to chronic cigarette smoke. The ET-1 contents in the medulla oblongata and midbrain of both strains were clearly increased by smoke exposure, although the levels of SHR and WKY rats were not different. In addition, the immunoreactivity of the ET type A receptor in the adrenal glands and type B receptor in the kidneys of SHR showed a different response to smoke exposure as compared to WKY rats. Our present findings suggest that the changes of ETs may relate to the pharmacodynamic effects of chronic cigarette smoke.