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

The Impact of Age on the Physiological Assessment of Borderline Coronary Stenoses

Background and Objectives: Coronary angiography is the gold standard for diagnosing coronary artery disease (CAD). In the case of borderline changes, patients require further diagnosis through ischemia assessment via one of the recommended methods of invasive evaluation. This study aimed to assess whether clinical factors influence the risk of a positive result in invasive myocardial ischemia assessment and if these potential factors change with the patient's age and the consistency of ischemia assessment. Materials and Methods: Data were collected retrospectively on all consecutive patients hospitalized in the University Hospital in Krakow between 2020 and 2021, on whom physiological assessments of coronary circulation were performed. Patients were divided into two groups: patients aged 60 or younger and patients older than 60. Results: Despite the older patients having more risk factors for CAD, their physiological assessment results of borderline lesions were similar to those of the younger patients. Positive fractional flow reserve (FFR) assessments were obtained from almost 50% of vessels. In the younger patients, cigarette use and type 2 diabetes mellitus increased the risk of a positive FFR result by 3.5 and 2.5 times, respectively. In the older patients, male gender and peripheral vascular disease significantly increased the risk of a positive FFR by 2.5 and 2 times, respectively. Conclusions: Clinical characteristics of patients undergoing physiological assessment of borderline coronary stenosis varied significantly by age. Refining the definition of borderline lesions to include age, gender, and other factors may improve the identification of patients who would benefit from physiological assessment and coronary revascularization.

Free Radicals and Obesity-Related Chronic Inflammation Contrasted by Antioxidants: A New Perspective in Coronary Artery Disease

We are surrounded by factors called free radicals (FR), which attach to the molecules our body is made of, first among them the endothelium. Even though FR are to a certain extent a normal factor, nowadays we face an escalating increase in these biologically aggressive molecules. The escalating formation of FR is linked to the increased usage of man-made chemicals for personal care (toothpaste, shampoo, bubble bath, etc.), domestic laundry and dish-washer detergents, and also an ever wider usage of drugs (both prescription and over the counter), especially if they are to be used long-term (years). In addition, tobacco smoking, processed foods, pesticides, various chronic infectious microbes, nutritional deficiencies, lack of sun exposure, and, finally, with a markedly increasing impact, electromagnetic pollution (a terribly destructive factor), can increase the risk of cancer, as well as endothelial dysfunction, owing to the increased production of FR that they cause. All these factors create endothelial damage, but the organism may be able to repair such damage thanks to the intervention of the immune system supported by antioxidants. However, one other factor can perpetuate the state of inflammation, namely obesity and metabolic syndrome with associated hyperinsulinemia. In this review, the role of FR, with a special emphasis on their origin, and of antioxidants, is explored from the perspective of their role in causing atherosclerosis, in particular at the coronary level.

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.

Aging increases circulating BH2 without modifying BH4 levels and impairs peripheral vascular function in healthy adults

Little is known about the mechanisms of aging on vascular beds and its relationship with tetra and di-hydrobiopterin (BH4 and BH2) levels. This observational clinical study analyzed the impact of aging on plasma and platelet biopterins, cutaneous blood flow (CBF), and coronary flow reserve (CFR) in healthy adults. The study enrolled healthy adults in 3 age groups: 18-30, 50-59, and 60-70 years (n = 25/group). Biopterins were assessed by LC-MS/MS using newly defined pre-analytical conditions limiting BH4 oxidation and improving long-term stability. CBF was measured by Laser Speckle Contrast Imaging coupled with acetylcholine-iontophoresis and CFR by adenosine stress cardiac magnetic resonance. In healthy adults, aging (60-70 years vs 18-30 years) significantly increased platelet BH2 (+75%, P = 0.033) and BH2 + BH4 (+31%, P = 0.033), and to a lesser extent plasma BH2 (+29%, P = 0.009) without affecting BH4 and BH4/BH2. Simultaneously, CBF was decreased (-23%, P = 0.004) but not CFR, CBF being inversely correlated with platelet BH2 (r = -0.42, P = 0.001) and BH2 + BH4 (r = -0.41, P = 0.002). The proportion of adults with abnormal platelet BH2 increased with age (+28% in 60-70y). These abnormal BH2 levels were significantly associated with reduced CBF and CFR (-16%, P = 0.03 and -26%, P = 0.02). In conclusion, our study showed that age-related peripheral endothelial dysfunction was associated with an increase in circulating BH2 without decreasing BH4, the effect being more marked in platelets, the most relevant blood compartment to assess biopterin bioavailability. Peripheral but not coronary vascular function is progressively impaired with aging in healthy adults. All these findings support biopterins as therapeutic targets to improve vascular function.

Echocardiographic assessment of coronary microvascular dysfunction: Basic concepts, technical aspects, and clinical settings

Coronary flow reserve is the capacity of the coronary circulation to augment the blood flow in response an increase in myocardial metabolic demands and has a powerful prognostic significance in different clinical situations. It might assess with invasive and noninvasive technique. Transthoracic echocardiography Doppler is an emerging diagnostic technique, noninvasive, highly feasible, safe for patient and physician, without radiation, and able to detect macrovascular and microvascular anomalies in the coronary circulation. This review aims to describe the benefit and limits of echocardiographic assessment of coronary flow reserve.

Smoking and Endothelial Dysfunction

Cigarette smoking is one of the most important health concerns worldwide. Even though the rate of smoking is declining in developed countries, it is still experiencing growth in developing regions. Many studies have examined the relationship between smoking, as an established risk factor, and cardiovascular diseases. We provide an updated review of the underlying mechanisms of smokinginduced cardiovascular diseases, with a focus on the relationship between smoking and oxidative stress, particularly from the perspective of endothelial cell dysfunction. We review smoking-induced oxidative stress as a trigger for a generalized vascular inflammation associated with cytokine release, adhesion of inflammatory cells and, ultimately, disruption of endothelial integrity as a protective barrier layer. We also briefly discuss the harms related to the vaping of electronic cigarettes, which many erroneously consider as a safe alternative to smoking. We conclude that even though e-cigarette could be a helpful device during the transition period of cigarette quitting, it is by no means a safe substitute.

Acute Effect of Hookah Smoking on Arterial Stiffness and Wave Reflections in Adults Aged 18 to 34 Years of Age

Hookah (waterpipe) smoking is rapidly increasing in popularity worldwide. Despite being heavily advertised in the media as a healthier alternative to cigarettes, the toxicology of hookah smoke suggest otherwise. Cigarette smoking unequivocally causes an acute increase in arterial stiffness, but whether hookah does the same is unknown. In 48 young healthy habitual hookah but not cigarette smokers, we measured heart rate, peripheral and central blood pressure, carotid-femoral pulse wave velocity (measure of arterial stiffness), aortic augmentation index (measure of wave reflection), plasma nicotine, and exhaled carbon monoxide before and after ad lib hookah smoking. Hookah smoking increased heart rate by +16 ± 1 beats/min and mean brachial arterial pressure by +6 ± 1 mm Hg (both p <0.05, mean ± SE). Most importantly, it increased carotid-femoral pulse wave velocity and aortic augmentation index by +0.66 ± 0.09 m/s^-1 and +8.76 ± 3.99%, respectively (p <0.05, mean ± SE), denoting increased acute arterial stiffness. These vascular effects were accompanied by increases in plasma nicotine concentration (+5.8 ± 1.2 ng/ml, p <0.05) and expired carbon monoxide (+25.44 ± 1.68 ppm, p <0.05). All these parameters were unchanged during time-control studies (n = 14). Thus, in contrast to effective media marketing of hookah as a safer alternative to cigarettes, the present study shows for the first time that in young adult hookah smokers, a single hookah smoking session causes an acute increase in arterial stiffness of comparable magnitude to what has been previously reported for cigarettes. Further research is warranted to determine whether habitual hookah smoking accelerates the age-dependent development of hypertension and its cardiovascular complications.

Acute Effect of Hookah Smoking on the Human Coronary Microcirculation

Hookah (water pipe) smoking is a major new understudied epidemic affecting youth. Because burning charcoal is used to heat the tobacco product, hookah smoke delivers not only nicotine but also large amounts of charcoal combustion products, including carbon-rich nanoparticles that constitute putative coronary vasoconstrictor stimuli and carbon monoxide, a known coronary vasodilator. We used myocardial contrast echocardiography perfusion imaging with intravenous lipid shelled microbubbles in young adult hookah smokers to determine the net effect of smoking hookah on myocardial blood flow. In 9 hookah smokers (age 27 ± 5 years, mean ± SD), we measured myocardial blood flow velocity (β), myocardial blood volume (A), myocardial blood flow (A × β) as well as myocardial oxygen consumption (MVO2) before and immediately after 30 minutes of ad lib hookah smoking. Myocardial blood flow did not decrease with hookah smoking but rather increased acutely (88 ± 10 to 120 ± 19 a.u./s, mean ± SE, p = 0.02), matching a mild increase in MVO2 (6.5 ± 0.3 to 7.6 ± 0.4 ml·minute(-1), p <0.001). This was manifested primarily by increased myocardial blood flow velocity (0.7 ± 0.1 to 0.9 ± 0.1 second(-1), p = 0.01) with unchanged myocardial blood volume (133 ± 7 to 137 ± 7 a.u., p = ns), the same pattern of coronary microvascular response seen with a low-dose β-adrenergic agonist. Indeed, with hookah, the increased MVO2 was accompanied by decreased heart rate variability, an indirect index of adrenergic overactivity, and eliminated by β-adrenergic blockade (i.v. propranolol). In conclusion, nanoparticle-enriched hookah smoke either is not an acute coronary vasoconstrictor stimulus or its vasoconstrictor effect is too weak to overcome the physiologic dilation of coronary microvessels matching mild cardiac β-adrenergic stimulation.

Arterial Compliance and Autonomic Functions in Adult Male Smokers

INTRODUCTION

Smoking is known to augment sympathetic activity and may lead to increased arterial stiffness. Several studies have reported association of increased sympathetic activity and arterial stiffness to cardiovascular risks among smokers. Pulse Wave Velocity (PWV) of peripheral arteries, instead of aorta can be used as a non-invasive indicator of arterial stiffness.

AIM

To measure non-invasively, the autonomic functions and peripheral arterial stiffness in smokers, and to find out whether the aforementioned factors are modified by the level of physical activity in these smokers.

MATERIALS AND METHODS

This cross-sectional analytical study was conducted in the Department of Physiology, HIMS, Dehradun, over a period of 12 months (2013-2014) on 100 adult males (20-40 years); 50 smokers and 50 non-smokers. The parameters analysed include relevant anthropometric and cardiovascular parameters, Pulse Wave Velocity (PWV), sustained Hand Grip Test (HGT) and Heart Rate Variability (HRV) domains. Data interpretation and analysis was carried out using SPSS 17.0. Comparison of the above mentioned parameters amongst groups was done with unpaired t-test. The relationship of pack-years & physical activity with vascular functions was assessed by Pearson's correlation. Interaction of various grades of smoking and physical activity with Cardiovascular System (CVS) parameters was assessed by one-way ANOVA.

RESULTS

Smokers had higher values of PWV (5.7±0.5m/s) as compared to non-smokers (4.8±0.4m/s) (p<0.001). ΔDBP during HGT was lower (7±3.18mmHg) among smokers as compared to non-smokers (19.4±3.5mmHg) (p<0.001). Smoking (pack-years) was positively related to PWV (r= .03) but showed a weak negative relationship with change in Diastolic Blood Pressure (ΔDBP) (r= -0.084, p=0.56) showing that, more the frequency of smoking, the more was arterial stiffening and the lesser was the sympathetic response to the HGT. The smokers had significantly higher sympathetic activity; Low Frequency (LF) & Low Frequency: High Frequency ratio (LF: HF) (p<.001) whereas High Frequency (HF) was significantly lower (p<.001) showing a decline in parasympathetic activity.

CONCLUSION

Smokers demonstrated higher peripheral PWV and higher intrinsic sympathetic activity and this increase in intrinsic sympathetic activity may lead to increased arterial stiffness. Interaction of autonomic function and PWV with levels of physical activity and grades of smoking showed no significant differences, suggesting the fact that increased physical activity or reduced smoking may not have any effect on the endothelial dysfunction or CVS morbidity caused by smoking.

The association of ADORA2A and ADORA2B polymorphisms with the risk and severity of chronic heart failure: a case-control study of a northern Chinese population

The causes of chronic heart failure (CHF) and its progression are likely to be due to complex genetic factors. Adenosine receptors A2A and A2B (ADORA2A and ADORA2B, respectively) play an important role in cardio-protection. Therefore, polymorphisms in the genes encoding those receptors may affect the risk and severity of CHF. This study was a case-control comparative investigation of 300 northern Chinese Han CHF patients and 400 ethnicity-matched healthy controls. Four common single-nucleotide polymorphisms (SNPs) of ADORA2A (rs2236625, rs2236624, rs4822489, and rs5751876) and one SNP of ADORA2B (rs7208480) were genotyped and an association between SNPs and clinical outcomes was evaluated. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association. The rs4822489 was significantly associated with the severity of CHF after adjustment for traditional cardiovascular risk factors (p = 0.040, OR = 1.912, 95% CI = 1.029–3.550). However, the five SNPs as well as the haplotypes were not found to be associated with CHF susceptibility. The findings of this study suggest that rs4822489 may contribute to the severity of CHF in the northern Chinese. However, further studies performed in larger populations and aimed at better defining the role of this gene are required.

Impact of smoking on coronary microcirculatory resistance in patients with coronary artery disease

The aim of this study was to investigate the relationship between coronary microvascular function and smoking using the 3 parameters fractional flow reserve (FFR), coronary flow reserve (CFR(thermo)), and index of microcirculatory resistance (IMR) in patients with coronary artery disease (CAD). A total of 97 CAD patients with 148 intermediate stenotic lesions were divided into two groups: current and former smokers (Smokers: n = 54), and those who had never smoked (Non-smokers: n = 43). Coronary physiology measurements were made following coronary angiography at rest and during hyperemia induced with intravenous adenosine triphosphate. If a patient had several intermediate lesions, the lesion producing the largest IMR value and minimum FFR(myo) and CFR(thermo) value was selected. Averaged over all patients, the FFR(myo), CFR(thermo), and IMR values were 0.86 ± 0.10, 2.66 ± 1.50, and 20.8 ± 10.7, respectively. There was no significant correlation between FFR(myo) and IMR. There were no significant differences between smokers and non-smokers in FFR(myo) value (median: 0.85 [IQR: 0.74-0.90] versus 0.87 [IQR: 0.83-0.90], P = 0.15) and CFR(thermo) value (median: 1.90 [IQR: 1.56-3.16] versus 2.10 [IQR: 1.50-2.67] U, P = 0.95). The IMR value was significantly greater in smokers (median: 24.2 [IQR: 16.8-32.5] U versus 18.5 [IQR: 15.4-27.0] U, P = 0.04). In multivariate analysis, smoking was an independent predictor of increased IMR. Smoking appears to have a detrimental effect on coronary microvascular function as measured by IMR.

The effects of chronic cigarette smoking on gray matter volume: influence of sex

Cigarette smoke contains nicotine and toxic chemicals and may cause significant neurochemical and anatomical brain changes. Voxel-based morphometry studies have examined the effects of smoking on the brain by comparing gray matter volume (GMV) in nicotine dependent individuals (NDs) to nonsmoking individuals with inconsistent results. Although sex differences in neural and behavioral features of nicotine dependence are reported, sex differences in regional GMV remain unknown. The current study examined sex differences in GMV in a large sample of 80 NDs (41 males) and 80 healthy controls (41 males) using voxel-based morphometry. Within NDs, we explored whether GMV was correlated with measures of cigarette use and nicotine dependence. High-resolution T1 structural scans were obtained from all participants. Segmentation and registration were performed in SPM8 using the optimized DARTEL approach. Covariates included age and an estimate of total global GMV. Differences were considered significant at p≤0.001, with a whole brain FWE-corrected cluster probability of p<0.025. Among NDs compared to Controls less GMV was observed in the thalamus and bilateral cerebellum and greater GMV was observed in the bilateral putamen and right parahippocampus. Lower thalamic GMV was observed in both female and male NDs compared to Controls. Female NDs also had lower GMV in the left cerebellum and in the ventral medial and orbitofrontal cortices with no areas of greater GMV. Male NDs had lower GMV in bilateral cerebellum and greater GMV in bilateral parahippocampus and left putamen. Within male NDs, GMV in the left putamen was correlated with number of pack years. This study, conducted in a large cohort, contributes to our knowledge of brain morphology in nicotine addiction and provides additional evidence of sex-specific effects on GMV in NDs. Identifying brain vulnerabilities with respect to sex provides a methodological framework for personalized therapies to improve relapse rates for both sexes.

Evaluation of the endothelial function in hypertensive patients with 13N-ammonia PET

BACKGROUND

Essential hypertension is one of the main risk factors for the development of coronary artery disease (CAD). Hypertension causes endothelial dysfunction which is considered an early sign for the development of CAD. Positron emission tomography is a non-invasive imaging technique that measures myocardial blood flow (MBF), allowing us to identify patients with endothelial dysfunction.

METHODS AND RESULTS

19 patients without comorbidities recently diagnosed hypertensive, as well as 21 healthy volunteers were studied. A three-phase (rest, cold pressor test, and adenosine-induced hyperemia) (13)N-ammonia PET was performed, and MBF was measured. Endothelial-Dependent Vasodilation Index, ΔMBF, and coronary flow reserve (CFR) were calculated for each patient. Hypertensive patients had a significantly higher systolic and diastolic blood pressures compared with the control group (134.6 ± 11.7/86.4 ± 10.6 mm Hg and 106.0 ± 11.8/71.4 ± 6.6 mm Hg, respectively, P < .001). The ENDEVI (1.28 ± 0.26 vs 1.79 ± 0.30, P < .001), the ΔMBF (0.81 ± 0.50 vs 0.25 ± 0.21, P < .001) and the CFR (2.18 ± 0.88 vs 3.17 ± 0.68, P = .001) were significantly lower in the hypertensive patients compared to the control group, 84% of the former group had endothelial dysfunction i.e., ENDEVI < 1.5 and 58% had vasomotor abnormalities, i.e., CFR < 2.5.

CONCLUSIONS

In this study, we showed that recently diagnosed hypertensive patients have coronary endothelial dysfunction and vasomotor disturbances which are early signs for the development of CAD.

Cigarette smoking exposure and heart failure risk in older adults: the Health, Aging, and Body Composition Study

BACKGROUND

Although there is evidence linking smoking and heart failure (HF), the association between lifetime smoking exposure and HF in older adults and the strength of this association among current and past smokers is not well known.

METHODS

We examined the association between smoking status, pack-years of exposure, and incident HF risk in 2,125 participants of the Health, Aging, and Body Composition Study (age 73.6 ± 2.9 years, 69.7% women, 54.2% whites) using proportional hazard models.

RESULTS

At inception, 54.8% of participants were nonsmokers, 34.8% were past smokers, and 10.4% were current smokers. During follow-up (median 9.4 years), HF incidence was 11.4 per 1,000 person-years in nonsmokers, 15.2 in past smokers (hazard ratio [HR] vs nonsmokers 1.33, 95% CI 1.01-1.76, P = .045), and 21.9 in current smokers (HR 1.93, 95% CI 1.30-2.84, P = .001). After adjusting for HF risk factors, incident coronary events, and competing risk for death, a dose-effect association between pack-years of exposure and HF risk was observed (HR 1.09, 95% CI 1.05-1.14, P < .001 per 10 pack-years). Heart failure risk was not modulated by pack-years of exposure in current smokers. In past smokers, HR for HF was 1.05 (95% CI 0.64-1.72) for 1 to 11 pack-years, 1.23 (95% CI 0.82-1.83) for 12 to 35 pack-years, and 1.64 (95% CI 1.11-2.42) for >35 pack-years of exposure in fully adjusted models (P < .001 for trend) compared with nonsmokers.

CONCLUSIONS

In older adults, both current and past cigarette smoking increase HF risk. In current smokers, this risk is high irrespective of pack-years of exposure, whereas in past smokers, there was a dose-effect association.

Telomere length is a biomarker of cumulative oxidative stress, biologic age, and an independent predictor of survival and therapeutic treatment requirement associated with smoking behavior

Globally, tobacco use is associated with 5 million deaths per annum and is regarded as one of the leading causes of premature death. Major chronic disorders associated with smoking include cardiovascular diseases, several types of cancer, and chronic obstructive pulmonary disease (lung problems). Cigarette smoking (CS) generates a cumulative oxidative stress, which may contribute to the pathogenesis of chronic diseases. Mainstream and side stream gas-phase smoke each have about the same concentration of reactive free radical species, about 1 × 10(16) radicals per cigarette (or 5 × 10(14) per puff). This effect is critical in understanding the biologic effects of smoke. Several lines of evidence suggest that cigarette smoke constituents can directly activate vascular reactive oxygen species production. In this work we present multiple evidence that CS provide the important risk factors in many age-related diseases, and is associated with increased cumulative and systemic oxidative stress and inflammation. The cited processes are marked by increased white blood cell (leucocytes, WBCs) turnover. The data suggest an alteration of the circulating WBCs by CS, resulting in increased adherence to endothelial cells. Telomeres are complex DNA-protein structures located at the end of eukaryotic chromosomes. Telomere length shortens with biologic age in all replicating somatic cells. It has been shown that tobacco smoking enhances telomere shortening in circulating human WBCs. Telomere attrition (expressed in WBCs) can serve as a biomarker of the cumulative oxidative stress and inflammation induced by smoking and, consequently, show the pace of biologic aging. We originally propose that patented specific oral formulations of nonhydrolized carnosine and carcinine provide a powerful tool for targeted therapeutic inhibition of cumulative oxidative stress and inflammation and protection of telomere attrition associated with smoking. The longitudinal studies of the clinical population groups described in this study including elderly support the hypothesis that telomere length is a predictor of survival and therapeutic treatment requirement associated with smoking behavior.

Effects of smoking on coronary microcirculatory function: a twin study

BACKGROUND

In asymptomatic smokers, coronary microcirculatory dysfunction, assessed by coronary flow reserve (CFR), is an early indicator of cardiovascular risk. Inflammation and oxidative stress may be the mechanisms through which smoking affects the microvasculature.

OBJECTIVES

The purpose of this study was to determine the relationship between smoking and CFR, taking into account potential shared genetic effects.

METHODS

We examined 360 male middle aged twins (288 non-smokers and 72 smokers), including 46 twin pairs discordant for current smoking. Coronary flow reserve (CFR) in response to adenosine was measured with positron emission tomography [N(13)] ammonia and quantitation of coronary blood flow at rest and after adenosine stress. Inflammation was assessed by measuring interleukin-6 and C-reactive protein, and oxidative stress was determined by measuring plasma hydroperoxides, glutathione (GSH), the oxidized form of GSH, GSSG, and the ratio of GSH to GSSG.

RESULTS

CFR was significantly lower in smokers compared to nonsmokers (2.25 vs. 2.75, p<0.01). This relationship persisted after accounting for known cardiovascular disease risk factors, and was marginally affected by adjusting for inflammatory and oxidative stress biomarkers. In addition, in smoking-discordant twin pairs, CFR in the smoking twin was significantly lower than in the non-smoking co-twin (2.25 vs. 2.67, p=0.03) even after adjustment for cardiovascular risk factors.

CONCLUSIONS

Our results demonstrate the adverse effects of smoking in the early phases of cardiovascular disease. Mechanisms other than peripherally measured inflammation and oxidative stress are involved.

Oxidative stress and accelerated vascular aging: implications for cigarette smoking

Cigarette smoking is the major cause of preventable morbidity and mortality in the United States and constitutes a major risk factor for atherosclerotic vascular disease, including coronary artery disease and stroke. Increasing evidence supports the hypothesis that oxidative stress and inflammation provide the pathophysiological link between cigarette smoking and CAD. Previous studies have shown that cigarette smoke activates leukocytes to release reactive oxygen and nitrogen species (ROS/RNS) and secrete pro-inflammatory cytokines, increases the adherence of monocytes to the endothelium and elicits airway inflammation. Here we present an overview of the direct effects of water-soluble cigarette smoke constituents on endothelial function, vascular ROS production and inflammatory gene expression. The potential pathogenetic role of peroxynitrite formation, and downstream mechanisms including poly(ADP-ribose) polymerase (PARP) activation in cardiovascular complications in smokers are also discussed.

Vasoprotective effects of resveratrol and SIRT1: attenuation of cigarette smoke-induced oxidative stress and proinflammatory phenotypic alterations

The dietary polyphenolic compound resveratrol, by activating the protein deacetylase enzyme silent information regulator 2/sirtuin 1 (SIRT1), prolongs life span in evolutionarily distant organisms and may mimic the cytoprotective effects of dietary restriction. The present study was designed to elucidate the effects of resveratrol on cigarette smoke-induced vascular oxidative stress and inflammation, which is a clinically highly relevant model of accelerated vascular aging. Cigarette smoke exposure of rats impaired the acetylcholine-induced relaxation of carotid arteries, which could be prevented by resveratrol treatment. Smoking and in vitro treatment with cigarette smoke extract (CSE) increased reactive oxygen species production in rat arteries and cultured coronary arterial endothelial cells (CAECs), respectively, which was attenuated by resveratrol treatment. The smoking-induced upregulation of inflammatory markers (ICAM-1, inducible nitric oxide synthase, IL-6, and TNF-alpha) in rat arteries was also abrogated by resveratrol treatment. Resveratrol also inhibited CSE-induced NF-kappaB activation and inflammatory gene expression in CAECs. In CAECs, the aforementioned protective effects of resveratrol were abolished by knockdown of SIRT1, whereas the overexpression of SIRT1 mimicked the effects of resveratrol. Resveratrol treatment of rats protected aortic endothelial cells against cigarette smoking-induced apoptotic cell death. Resveratrol also exerted antiapoptotic effects in CSE-treated CAECs, which could be abrogated by knockdown of SIRT1. Resveratrol treatment also attenuated CSE-induced DNA damage in CAECs (comet assay). Thus resveratrol and SIRT1 exert antioxidant, anti-inflammatory, and antiapoptotic effects, which protect the endothelial cells against the adverse effects of cigarette smoking-induced oxidative stress. The vasoprotective effects of resveratrol will likely contribute to its antiaging action in mammals and may be especially beneficial in pathophysiological conditions associated with accelerated vascular aging.

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.

Effects of chronic smoking on exercise tolerance and on heart rate-systolic blood pressure product in young healthy adults

BACKGROUND

Smoking is a major cause of cardiovascular disease and mortality. Smoking-related deaths in Greece account for 23%, whereas 41% of young Greeks are smokers, the highest percentage in Europe. The purpose of this study was to examine the effects of chronic smoking on the rate-pressure product and exercise tolerance in young, healthy male smokers.

DESIGN AND METHODS

Forty-two smokers and 51 nonsmokers were selected from a population of 543 students based on their age, sex, body mass index, physical fitness, smoking habit and health status. All participants were tested with the standard Bruce treadmill protocol. The rate-pressure product was obtained at rest and during exercise at a given submaximal workload. The evaluation of exercise tolerance was based on peak workload achieved and maximal exercise test duration.

RESULTS

The smokers had a higher rate-pressure product at rest (P<0.001) due to their higher resting heart rate (P<0.001). Resting values of blood pressure did not differ significantly between the two groups. During exercise, smokers had a greater rate-pressure product (P<0.001), mainly due to their significantly higher systolic blood pressure (P=0.008). The smokers had a higher submaximal heart rate (P=0.005), but the differences in heart rate between groups were reduced for smokers during exercise when compared to rest. The smokers' exercise tolerance was impaired and their maximal exercise test duration time was significantly shorter (P<0.001).

CONCLUSIONS

Chronic smoking was found to affect young male smokers' cardiovascular fitness, impairing the economy and decreasing the capacity of their circulatory system.

Difference in myocardial flow reserve between patients with dilated cardiomyopathy and those with dilated phase of hypertrophic cardiomyopathy: evaluation by 15O-water PET

BACKGROUND

The clinical features of patients with the dilated phase of hypertrophic cardiomyopathy (DHCM) may resemble those of patients with dilated cardiomyopathy (DCM); that is, systolic dysfunction and left ventricular dilatation. Myocardial flow reserve (MFR) is impaired in patients with nonischemic cardiomyopathy, and the reduced MFR may be related to poor prognosis. Several studies report that the mortality rate for patients with DHCM is higher than for DCM, but the difference between these 2 cardiomyopathies is still unclear. The purpose of this study was to assess the MFR of these 2 cardiomyopathies, using (15)O-water positron emission tomography (PET) to elucidate their differences.

METHODS AND RESULTS

In total 30 patients were investigated: 23 with DCM (Group A) and 7 with DHCM (Group B). All those who were in a stable condition underwent cardiac catheterization. Myocardial blood flow (MBF) at rest and under ATP infusion was measured by (15)O-water PET, and the MFR was calculated. There were no significant differences in the hemodynamics of the 2 groups. The mean MFR in DHCM was significantly lower than that in DCM (1.49+/-0.31 vs 2.62+/-1.08; p=0.042), whereas MBF at rest did not differ (DCM vs DHCM: 0.66+/-0.20 vs 0.49+/-0.05 ml . min(-1) . g(-1); NS). The MFR in both Group A and B was significantly decreased compared with the normal controls (MFR in normal controls: 5.15+/-1.64, p=0.00015, 0.00013, respectively).

CONCLUSIONS

These results suggest that impaired vasodilatation (ie, dysfunction of the microcirculation) is more severe in patients with DHCM than in patients with DCM, even though patients' characteristics and hemodynamics do not differ.

Examination of the microcirculation damage in smokers versus nonsmokers with vasospastic angina pectoris

Endothelial dysfunction is considered one of the mechanisms underlying vasospastic angina pectoris (VSA). It is also known that smokers have abnormalities in endothelial dysfunction. Although smoking is a major risk factor for coronary artery disease, microvascular abnormalities have not been well shown. We investigated clinical characteristics and coronary reactivity with adenosine triphosphate in smokers with VSA. Twenty-two consecutive patients whose coronary spasm was documented in the left anterior descending (LAD) coronary artery with acetylcholine were enrolled. Coronary blood flow responses were also evaluated by intracoronary Doppler flow velocity recordings in the LAD coronary artery. Average peak velocities (APVs) were measured at baseline and intracoronary administration of adenosine triphosphate (50 microg) in 11 smokers (age 60+/-9 years; 8 men) and 11 nonsmokers (age 61+/-10 years, 5 men). Coronary flow reserve (CFR) was calculated by the ratio of baseline to hyperemic APV. Multivessel spasm was demonstrated in 6 smokers and only 2 nonsmokers (p<0.05). APV at rest in smokers (13.4+/-3.0 cm/s) was similar to that in nonsmokers (13.5+/-2.9 cm/s). However, CFR in smokers (2.6+/-0.7) was significantly lower than in nonsmokers (3.4+/-0.8; p<0.05). In conclusion, multivessel spasm was demonstrated in smokers in clinical settings, and microcirculation damage is prominent in smokers with VSA.

Acute effects of smoking on coronary flow velocity reserve and ventricular diastolic functions

Although it is well known that chronic effect of smoking on cardiovascular system, relation between coronary vascular reactivity and ventricular functions after acute smoking has not been well understood. The purpose of this study was to assess the relation between coronary flow velocity reserve and ventricular diastolic functions measured by tissue Doppler imaging after acute smoking. We found that coronary flow velocity and diastolic functions of right ventricle were decreased. Also, there was a correlation between coronary flow velocity reserve and diastolic ratio of the ventricle. Acute smoking may affect diastolic functions of the ventricles, especially right ventricle via changes of coronary flow.

Endothelial dysfunction in patients with antiphospholipid syndrome assessed with positron emission tomography

BACKGROUND

There is limited knowledge about endothelial dysfunction in patients with primary antiphospholipid syndrome (PAPS). The purpose of this study was to evaluate endothelial function in patients with PAPS assessed by positron emission tomography.

METHODS AND RESULTS

A 3-phase protocol--rest, cold pressor test (CPT), and adenosine positron emission tomography with nitrogen 13 ammonia--was used in 18 patients with PAPS and 18 healthy volunteers (HVs). Myocardial blood flow (MBF) was measured in each phase, with calculation of the endothelial-dependent vasodilation index, the increase in the MBF in response to CPT, and the myocardial flow reserve. An important trend was found in the myocardial flow reserve (2.76 +/- 1.04 in PAPS group vs 3.27 +/- 0.72 in HV group, P > .05), in the endothelial-dependent vasodilation index (1.19 +/- 0.31 in PAPS group vs 1.55 +/- 0.37 in HV group, P < .05), and in the percent change in the MBF in response to CPT (from rest) (19% +/- 31% in PAPS group vs 55% +/- 37% in HV group, P < .05).

CONCLUSION

The CPT results obtained in this study showed that the PAPS patients studied have endothelial dysfunction.

Cigarette smoke-induced proinflammatory alterations in the endothelial phenotype: role of NAD(P)H oxidase activation

Although the cardiovascular morbidity and mortality induced by cigarette smoking exceed those attributable to lung cancer, the molecular basis of smoking-induced vascular injury remains unclear. To test the link between cigarette smoke, oxidative stress, and vascular inflammation, rats were exposed to the smoke of five cigarettes per day (for 1 wk). Also, isolated arteries were exposed to cigarette smoke extract (CSE; 0 to 40 μg/ml, for 6 h) in organoid culture. We found that smoking impaired acetylcholine-induced relaxations of carotid arteries, which could be improved by the NAD(P)H oxidase inhibitor apocynin. Lucigenin chemiluminescence measurements showed that both smoking and in vitro CSE exposure significantly increased vascular O2•− production. Dihydroethidine staining showed that increased O2•− generation was present both in endothelial and smooth muscle cells. CSE also increased vascular H2O2 production (dichlorofluorescein fluorescence). Vascular mRNA expression of the proinflammatory cytokines IL-1β, IL-6, and TNF-α and that of inducible nitric oxide synthase was significantly increased by both smoking and CSE exposure, which could be prevented by inhibition of NAD(P)H oxidase (diphenyleneiodonium and apocynin) or scavenging of H2O2. In cultured endothelial cells, CSE elicited NF-κB activation and increased monocyte adhesiveness, which were prevented by apocynin and catalase. Thus we propose that water-soluble components of cigarette smoke (which are likely to be present in the bloodstream in vivo in smokers) activate the vascular NAD(P)H oxidase. NAD(P)H oxidase-derived H2O2 activates NF-κB, leading to proinflammatory alterations in vascular phenotype, which likely promotes development of atherosclerosis, especially if other risk factors are also present.

Effects of smoking on coronary blood flow velocity and coronary flow reserve assessed by transthoracic Doppler echocardiography

BACKGROUND

Smoking is a well-known risk factor for cardiovascular disease. Coronary blood flow velocity (CFV) can be measured directly with transthoracic Doppler echocardiography (TTDE) which is conducted immediately after smoking.

PURPOSE

The purpose of this study was to evaluate the chronic and acute effects of smoking on coronary blood flow and coronary flow reserve (CFR) by the use of TTDE.

METHODS

Healthy volunteers (11 smokers and 9 nonsmokers) with a mean age of 27 +/- 3 years were included. Smoking was abstained for at least 4 hours before the study. CFV was measured at the distal left anterior descending coronary artery by TTDE at baseline and during intravenous adenosine infusion (140 microg/kg per minute) in all participants. For smokers, CFV was measured immediately after consecutively smoking two cigarettes and during adenosine infusion.

RESULTS

CFR and coronary vascular resistance index (CVRI) showed no significant difference between nonsmokers and smokers (CFR: 3.5 +/- 0.8 vs 3.6 +/- 0.6, P = ns, CVRI: 0.28 vs 0.28, P = ns) at baseline. CFR significantly decreased (3.6 +/- 0.6 to 2.8 +/- 0.7, P = 0.008) and CVRI markedly increased (0.28 to 0.35, P = 0.012) after smoking.

CONCLUSION

After 4 hours of abstinence from smoking, CFR and CVRI in smokers were similar to those of nonsmokers. However, consecutively smoking two cigarettes acutely reduced CFR and increased CVRI. These findings suggested that smoking could reduce coronary blood flow immediately, even in healthy people.

Cut-off value of coronary flow velocity reserve by transthoracic Doppler echocardiography for the assessment of significant donor left anterior descending artery stenosis in patients with spontaneously visible collaterals

We evaluated the influence of collateral circulation on a donor left anterior descending artery and an appropriate cut-off value of coronary flow velocity reserve for the diagnosis of significant donor left anterior descending artery stenosis. Measurement of coronary flow velocity reserve by transthoracic Doppler echocardiography provides noninvasive assessment of significant left anterior descending artery stenosis. The cut-off value of coronary flow velocity reserve for the diagnosis of significant donor left anterior descending artery stenosis has not been well studied. We retrospectively examined 64 patients who had no significant left anterior descending artery stenosis and who had other coronary artery stenosis. Seventeen patients had collaterals from the left anterior descending artery (group A) and 47 patients did not have collaterals (group B). We prospectively examined 23 consecutive patients who had collaterals from the left anterior descending artery to other coronary arteries. Eight patients had a significant donor left anterior descending artery stenosis. Coronary flow velocity reserve assessment was performed by transthoracic Doppler echocardiography in the 2 protocols. Coronary flow velocity at baseline in group A was significantly higher than that in group B. Coronary flow velocity reserve in group A was significantly lower than that in group B (2.6 +/- 0.8 vs 3.2 +/- 0.9, p < 0.05). Coronary flow velocity during hyperemia and coronary flow velocity reserve were significantly lower in patients with significant stenosis. A cut-off value of 2.0 of coronary flow velocity reserve had a sensitivity of 88% and a specificity of 93% for the diagnosis of significant donor left anterior descending artery stenosis. In conclusion, coronary flow velocity reserve of a donor left anterior descending artery was decreased by the presence of collaterals. However, a cut-off value < 2.0 was appropriate for the diagnosis of significant donor left anterior descending artery stenosis in a population that included patients with collaterals.

Myocardial flow reserve is influenced by both coronary artery stenosis severity and coronary risk factors in patients with suspected coronary artery disease

PURPOSE

Myocardial flow reserve (MFR) measurement has an important role in assessing the functional severity of coronary artery stenosis. However, a discrepancy between the anatomical severity of coronary artery stenosis and MFR is often observed. Such a discrepancy may be explained by coronary risk factors. In this study, we aimed to investigate the influence of coronary artery stenosis severity and risk factors on MFR.

METHODS

Seventy-four patients suspected to have coronary artery disease and seven age-matched healthy volunteers were enrolled. Myocardial blood flow (MBF) and MFR were measured using 15O-labelled water PET. Regional MFR was calculated in regions with significant coronary artery stenosis (stenotic regions) and in regions without significant stenosis (remote regions). The contributions of coronary artery stenosis severity and coronary risk factors were assessed using univariate and multivariate analyses.

RESULTS

In stenotic regions, MFR correlated inversely with coronary artery stenosis severity (r=-0.50, p<0.01). Univariate analysis did not show any significant difference in MFR between the patients with and the patients without each risk factor. In remote regions, however, MFR was significantly decreased in the diabetes and smoking groups (each p<0.05). By multivariate analysis, diabetes and smoking were independent predictors of MFR (each p<0.05). In the group with more than one risk factor, MFR was significantly lower (2.78+/-0.79) than in the other group (3.40+/-1.22, p<0.05).

CONCLUSION

MFR is influenced not only by coronary stenosis severity but also by coronary risk factors. In particular, the influence of risk factors should be considered in regions without severe coronary stenosis.

[Prevention of coronary heart disease: smoking]

Smoking is the leading preventable cause of illness and premature death in Germany, claiming over 110,000 lives a year because it directly increases the risk of dying from heart disease, stroke, emphysema and a variety of cancers. The overwhelming majority of smokers begin tobacco use before they reach adulthood. Among those young people who smoke, the average age is now 13-14. In Germany, about 39% of male and 31% of female adults (age 18-60 years) continue to smoke, despite information about the unequivocally negative health consequences of smoking. The exact mechanisms of smoking-related vascular disease are not yet known. Smoking causes acute hemodynamic alterations such as increase in heart rate, systematic and coronary vascular resistance, myocardial contractility, and myocardial oxygen demand. These short-term effects could lower the ischemic threshold in smokers with coronary artery disease and contribute to the increased risk for acute cardiovascular events. Endothelial damage is thought to be an initiating event in atherosclerosis and early studies have demonstrated that long-term smoking has direct toxic effects with structural changes of human endothelial cells. Recent research has shown the importance of the functional role of the endothelium in regulating vascular tone, platelet-endothelial interactions, leukocyte adhesion and smooth muscle cell proliferation via synthesis and release of a variety of substances such as nitric oxide. There is strong evidence that smoking leads to endothelial dysfunction mainly by increased inactivation of nitric oxide by oxygen-derived free radicals. Smoking also increases oxidative modification of LDL and is associated with lower HDL plasma levels. Smoking induces a systemic inflammatory response with increased leukocyte count and elevation of the C-reactive protein level. Importantly, the prothrombotic effects of smoking have been repeatedly demonstrated to cause alterations in platelet function, imbalance of antithrombotic vs prothrombotic factors, and decrease of fibrinolytic activity. Given the enormous health hazard of tobacco use, complete abstinence from smoking should be achieved. Smoking cessation counselling should be given to healthy subjects and even more vigorously to patients with manifested disease. Every effort should be undertaken to prevent children and adolescents from starting to smoke. Brief tobacco dependence treatment is effective, and every smoker should be offered at least brief treatment at every office visit. More intensive treatment is more effective in producing long-term abstinence from tobacco. Nicotine replacement therapy (nicotine patches or gum), clinician-delivered social support, and skills training are the three most effective components of smoking cessation treatment. A framework for tobacco control measures is necessary to reduce tobacco consumption and exposure to tobacco smoke. Recommendations on specific tobacco control interventions are: 1. increase in tobacco taxes; 2. comprehensive tobacco advertising bans; 3. legislation prohibiting smoking in work and public places; 4. prohibiting the sales of tobacco products to persons under 18; 5. comprehensive disclosure of the physical, chemical and design characteristics of all tobacco products; 6. training of health professionals to promote smoking prevention and cessation interventions; and 7. development of a national network of smoking cessation treatment services.

A calcium-channel blocker, benidipine, improves forearm reactive hyperemia in patients with essential hypertension

The pathophysiological role of endothelial cells is important in the mechanism of progression of atherosclerosis and improvement of endothelial function may be important for cardiovascular morbidity. Calcium antagonists are reported to have protective effects on the endothelium in vitro and in vivo. In this clinical study, we investigated the effect of calcium antagonist, benidipine, on endothelial function in the patients with essential hypertension, which causes endothelial dysfunction. Twenty-five patients with hypertension without other risk factors for atherosclerosis were treated with monotherapy (8 mg benidipine, n=25) for 8 weeks. Blood pressure was reduced significantly. Endothelial function was evaluated using forearm blood flow by strain-gauge plethysmography after 8 weeks of treatment. Changes in vasodilator response to reactive hyperemia were significantly improved (p<0.01), while the response to nitroglycerin was not changed, suggesting the improvement of endothelial function. Moreover, we focused on hepatocyte growth factor (HGF), which is a novel angiogenic growth factor with an anti-apoptotic action on endothelial cells, and evaluated involvement of HGF in improvement of endothelial function. Serum HGF concentration in subjects treated with benidipine was significantly elevated at 8 weeks (p<0.05). Overall, these results demonstrated that benidipine improved endothelial dysfunction in patients with hypertension. Interestingly, an increase in serum HGF concentration by benidipine might contribute to the improvement of endothelial dysfunction.

Differences in the immediate effects of smoking on left ventricular diastolic function between healthy volunteers and patients with type 2 diabetes mellitus

BACKGROUND

In contrast to in-depth studies on the chronic hazardous effects of smoking, the immediate effects of smoking on left ventricular function have not been evaluated in detail.

OBJECTIVES

We aimed to assess the hypothesis that smoking a cigarette might have more deleterious immediate impacts on left ventricular function in patients with diabetes mellitus than in healthy volunteers.

METHODS

In all, 20 patients with type 2 diabetes mellitus and 25 healthy volunteers were consecutively enrolled. Mitral inflow parameters (peak early and late diastolic velocities, and deceleration time of early diastolic mitral inflow) and mitral annulus velocity parameters (systolic, late, and early diastolic velocity [E']) were obtained together with heart rate and blood pressure before and 5, 15, 30, 45, 60, and 75 minutes after smoking a cigarette.

RESULTS

Transient elevations in heart rate and blood pressure were observed after smoking in both groups. In terms of mitral inflow parameters, transient trends toward abnormal relaxation were noted in both groups. For mitral annulus velocity parameters, in contrast to a temporary decrease in E' in healthy volunteers, reduction in E' persisted throughout the study for patients with diabetes. No significant change in peak early diastolic velocity/E' ratio was observed in healthy volunteers; however, a significant increase in peak early diastolic velocity/E' ratio lasted throughout the study period for patients with diabetes. Systolic velocity had no significant change during the study in either group.

CONCLUSIONS

Even one cigarette can induce more protracted and more severe left ventricular diastolic dysfunction in patients with type 2 diabetes mellitus than in healthy volunteers. Our results have clinically relevant implications in the current era of increasing recognition of the diabetes epidemic and of the associated cardiovascular risks.

Depression and smoking in coronary heart disease

OBJECTIVE

This review examines the relationship between depression and smoking in coronary heart disease (CHD). It summarizes relevant findings from general population and smoking cessation studies and discusses the few studies that have investigated whether smoking confounds, mediates, or moderates the effect of depression on cardiac morbidity and mortality.

METHODS

Qualitative review of research literature.

RESULTS

Although many studies of the prognostic importance of depression in CHD have adjusted for smoking, there is no convincing evidence that smoking actually confounds the relationship between depression and CHD. There is also no evidence that smoking moderates this relationship. There is, however, limited evidence that smoking may partially mediate the effect of depression on morbidity and mortality in CHD.

CONCLUSION

We need more research on the relationship between depression and smoking in CHD to develop a more complete model of the mechanisms linking depression to cardiac morbidity and mortality.

Effect of nifedipine on endothelial function in normotensive smokers: potential contribution of increase in circulating hepatocyte growth factor

Calcium antagonists are reported to have protective effects on the endothelium in vitro and in vivo. Especially, nifedipine, among many calcium antagonists, was shown to improve endothelial dysfunction in patients with hypertension. However, no report has determined whether the improvement of endothelial dysfunction by nifedipine is due to direct effects or indirect effects such as its hypotensive effect. Thus, in this study, we evaluated the direct effects of nifedipine on smoking-induced endothelial dysfunction, since cigarette smoking itself is a major factor in damage of endothelial cells, as well as hypertension. We examined whether nifedipine improves endothelial function in 10 normotensive smokers without any risk factors for atherosclerosis. The subjects were treated with 20 mg nifedipine monotherapy (n = 10) or placebo (n = 10) for 4 weeks. Nifedipine did not affect blood pressure and heart rate of normotensive smokers. We measured forearm blood flow (FBF) by strain-gauge plethysmography after 2 and 4 weeks of treatment. Changes in vasodilator response to reactive hyperaemia were significantly improved in nifedipine-treated subjects (P < 0.05), while there was no significant change in FBP response in control subjects. Response to nitroglycerin was not changed in either group. Moreover, to evaluate the mechanisms of the direct effects of nifedipine on the endothelium, we focused on hepatocyte growth factor (HGF), which is a novel angiogenic growth factor with an antiapoptotic action on endothelial cells. Interestingly, serum HGF concentration in smokers treated with nifedipine was significantly elevated both at 2 and 4 weeks (P < 0.05). Overall, these results demonstrated direct effects of nifedipine in the improvement of endothelial dysfunction in normotensive smokers. The increase in serum HGF concentration by nifedipine might contribute to the improvement of endothelial dysfunction.

Impact of Smoking Status on Long-Term Mortality in Patients With Acute Myocardial Infarction

BACKGROUND

Cessation of smoking after a cardiovascular event has been shown in Western countries to have a beneficial effect on clinical events during long-term follow-up. However, knowledge of the effect of smoking status after acute myocardial infarction (AMI) on the long-term mortality based on a large-scale sample is still limited in Japan.

METHODS AND RESULTS

In the present study 2,579 AMI patients were enrolled in the Osaka Acute Coronary Insufficiency Study (OACIS) between April 1998 and March 2003. Smoking status was assessed at baseline and 3 months after hospital discharge by mailed questionnaire. Patients were divided into nonsmokers (n=823), former smokers (those who had stopped smoking before AMI onset, n=332), quitters (those who stopped smoking after AMI onset, n=1,056), and persistent smokers (those who smoked before and after AMI, n=368). Quitters had lower long-term mortality rates than persistent smokers (3.0% vs 5.2%; log rank, p=0.032). Multivariate Cox regression analysis revealed that smoking cessation was independently associated with a reduction in risk of long-term mortality (hazard ratio, 0.39; 95% confidence interval, 0.20-0.77).

CONCLUSIONS

Patients who continue to smoke after AMI are at greater risk for death than patients who quit smoking. Cessation of smoking benefits the long-term prognosis in patients with AMI.

Acute Myocardial Infarction in Young Japanese Adults Clinical Manifestations and In-Hospital Outcome

BACKGROUND

The prevalence and clinical manifestations of acute myocardial infarction (AMI) in young patients in Japan have not been fully investigated.

METHODS AND RESULTS

In the present study, 1651 AMI patients were enrolled in the AMI-Kyoto Multi-Center Risk Study between January 2000 and June 2004. Of these, the clinical background, risk factors, angiographic findings, acute results of primary percutaneous coronary intervention (PCI) and in-hospital outcomes for 27 young patients <40 (young group), and 338 non-young patients 60<or=, <70 years old (non-young group) were retrospectively compared. The young AMI patients were all male. Current smoking, hypercholesterolemia and family history were the most common risk factors in young patients, while hypertension and diabetes mellitus were more prevalent in non-young patients. Young patients had a higher prevalence of single-vessel disease and a lesser incidence of left circumflex coronary artery as a culprit lesion. The young group had high acquisition rates of Thrombolysis In Myocardial Infarction 3 flow just after primary PCI (95.8%) and no in-hospital deaths, which was not significantly different from the non-young group.

CONCLUSIONS

These results suggest that young AMI patients have different clinical characteristics from those in non-young AMI patients, and acute results of primary PCI and in-hospital prognosis in young AMI patients are comparable to those in non-young AMI patients in Japan.

Potential utility of rubidium 82 PET quantification in patients with 3-vessel coronary artery disease

BACKGROUND

Standard perfusion imaging may underestimate the extent of disease in 3-vessel coronary atherosclerosis. This study determined whether positron emission tomography quantification of perfusion reserve by use of rubidium 82 net retention defined a greater extent of disease than the standard approach in patients with 3-vessel disease.

METHODS AND RESULTS

Rb-82 net retention was quantified as an estimation of absolute perfusion at rest and with dipyridamole stress by use of dynamic positron emission tomography imaging. The percent of abnormal myocardial sectors, as compared with a normal database, for a standard and quantification approach was determined. Twenty-three patients were evaluated. Defect sizes were larger in patients with 3-vessel disease (n = 13) by use of quantification methods: 44% +/- 18% of the myocardial sectors were abnormal by use of the standard approach versus 69% +/- 24% of sectors when measured by quantification of the stress-rest perfusion difference (P =.008). In patients with single-vessel disease (n = 10), defect sizes were smaller with quantification methods.

CONCLUSIONS

Quantification of Rb-82 net retention to measure the stress-rest perfusion difference in the myocardium defined a greater extent of disease than the standard approach in this group of patients with triple-vessel disease. More accurate measurement of the extent of coronary artery disease could facilitate better risk stratification and identify more high-risk patients in whom aggressive intervention is required.

The pathophysiology of cigarette smoking and cardiovascular disease: an update

Cigarette smoking (CS) continues to be a major health hazard, and it contributes significantly to cardiovascular morbidity and mortality. Cigarette smoking impacts all phases of atherosclerosis from endothelial dysfunction to acute clinical events, the latter being largely thrombotic. Both active and passive (environmental) cigarette smoke exposure predispose to cardiovascular events. Whether there is a distinct direct dose-dependent correlation between cigarette smoke exposure and risk is debatable, as some recent experimental clinical studies have shown a non-linear relation to cigarette smoke exposure. The exact toxic components of cigarette smoke and the mechanisms involved in CS-related cardiovascular dysfunction are largely unknown, but CS increases inflammation, thrombosis, and oxidation of low-density lipoprotein cholesterol. Recent experimental and clinical data support the hypothesis that cigarette smoke exposure increases oxidative stress as a potential mechanism for initiating cardiovascular dysfunction.

Effect of caffeine administered intravenously on intracoronary-administered adenosine-induced coronary hemodynamics in patients with coronary artery disease

It is believed that caffeine attenuates the coronary hyperemic response to adenosine by blocking the A2a receptors. We studied the effect of caffeine on adenosine-induced myocardial hyperemia measured by fractional flow reserve after intracoronary adenosine administration. Fractional flow reserve was not affected by intravenous caffeine infusion at a dose that was comparable to oral consumption.

Cut-off value of coronary flow velocity reserve by transthoracic Doppler echocardiography for diagnosis of significant left anterior descending artery stenosis in patients with coronary risk factors

The purpose of this study was to evaluate the adequate cut-off value of coronary flow velocity reserve (CFVR) with transthoracic Doppler echocardiography for diagnoses of significant left anterior descending (LAD) artery stenosis in a large study population with various coronary risk factors. CFVR, which has been used for evaluation of significant coronary artery stenosis, can be reduced despite angiographically normal coronary arteries in patients with various coronary risk factors. However, the adequate cut-off value of CFVR for diagnosing significant LAD stenosis has not been fully established in patients with coronary risk factors. We examined 138 consecutive patients who underwent coronary angiography. Clinical histories of coronary risk factors were determined from interviews or medical records. CFVR assessment in the LAD artery by transthoracic Doppler echocardiography was performed in all patients. Of the 138 patients, 30 had significant stenosis, and the remainder had no stenotic lesions in the LAD artery. Receiver-operating characteristic curves for detection of significant LAD stenosis showed that a cut-off value of <2.0 was extremely precise. A cut-off value <2.0 of CFVR had a sensitivity of 90%, a specificity of 93%, a positive predictive value of 77%, and a negative predictive value of 97% for the presence of significant LAD stenosis. A cut-off value <2.0 of CFVR by transthoracic Doppler echocardiography was adequate for the diagnosis of significant LAD stenosis in a population that included patients with coronary risk factors.

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

Smokers differ from nonsmokers in the way they present with acute coronary syndromes and in how they respond to treatment. Although smoking increases the risk of a coronary event and accelerates the progression of established atherosclerosis, paradoxically, smokers have better short-term survival after an acute myocardial infarction, mainly because they are younger and have more favorable coronary anatomy. Thrombolysis appears to be a better treatment in smokers than in nonsmokers, probably because thrombosis plays a more important role in the pathogenesis of acute coronary events in smokers. Patients who continue to smoke after angioplasty or bypass surgery have a worse outcome than nonsmokers or quitters. The 2.5- to 3-fold increase in risk for myocardial infarction or stroke in smokers compared with nonsmokers decreases exponentially after smoking cessation. By 4 years the risk is only slightly higher than the risk of a subject who never smoked.

Cigarette smoking and coronary blood flow

Cigarette smoking is associated with an increased risk for vascular disease. The effects of smoking and nicotine on coronary and peripheral arterial function have been probed with various invasive and noninvasive techniques. The current review provides a brief summary of the available techniques for measuring coronary or peripheral arterial function and discusses the determinants of myocardial blood flow at rest and during stress. Finally, it summarizes research addressing the effects of smoking on coronary and peripheral arterial function. Acute and chronic smoking does not appear to alter substantially endothelium independent coronary vasodilatory capacity. In contrast, active and passive smoking alters coronary and peripheral arterial vasomotion in patients with and individuals without coronary artery disease (CAD). Therefore, the site of the damaging effects of smoking appears to be the coronary endothelium. The smoking history is correlated with the degree of vasomotor abnormalities. Further, the degree of smoking-induced endothelial dysfunction appears to increase with the severity of CAD. Finally, the coronary endothelial and peripheral arterial vasomotor dysfunction observed in active and passive healthy smokers appear to be to some degree reversible.

Short-term effect of cigarette smoking on CO(2)-induced vasomotor reactivity in man: a study with near-infrared spectroscopy and tanscranial Doppler sonography

Cigarette smoking is a major risk factor for stroke, and quitting reduces the stroke risk within a few years. The aim of our study was to clarify whether CO(2)-induced vasomotor reactivity (VMR) is impaired in smokers after smoking a cigarette as a possible factor of an increased stroke risk. We compared VMR of 23 healthy smokers assessed at baseline, immediately, and 30 min after smoking a cigarette (1.2 mg nicotine) with values from nonsmoking, age-matched controls (n=24), obtained at identical time intervals. Cerebral blood flow velocities (CBFV) of both middle cerebral arteries (transcranial Doppler sonography), changes in concentration of cerebral oxygenated, deoxygenated, and total hemoglobin (HbO(2), Hb, and HbT, near-infrared spectroscopy), mean arterial blood pressure (MAP), and skin blood flow were recorded during normo- and hypercapnia. VMR was calculated as percentage change in CBFV and as micromolar change in concentration of HbO(2), Hb, and HbT per 1% increase in endtidal CO(2). CBFV in smokers was increased at baseline (left, p<0.05; right, p=0.05), immediately (p<0.01), and 30 min after smoking (p<0.05) as compared with nonsmokers. MAP rose immediately after smoking (p<0.01) and declined after 30 min. VMR in smokers at baseline did not differ from controls, decreased immediately after smoking (p<0.05), and normalized after 30 min (p>0.05). Increased baseline CBFV in smokers after smoking might be due to arteriolar dilation, increased MAP, and possibly constriction of basal cerebral arteries. Impaired VMR for about 30 min after smoking reflects endothelial dysfunction. This might contribute to the enhanced stroke risk in smokers.