‘Smoker's paradox’ in young patients with acute myocardial infarction

Live to die another day: novel insights may explain the pathophysiology behind smoker's paradox in SARS-CoV-2 infection

The severe acute respiratory coronavirus 2 (SARS-CoV-2) infection demonstrates a highly variable and unpredictable course. Several reports have claimed a smoker's paradox in coronavirus disease 2019 (COVID-19), in line with previous suggestions that smoking is associated with better survival after acute myocardial infarction and appears protective in preeclampsia. Several plausible physiological explanations exist accounting for the paradoxical observation of smoking engendering protection against SARS-CoV-2 infection. In this review, we delineate novel mechanisms whereby smoking habits and smokers' genetic polymorphism status affecting various nitric oxide (NO) pathways (endothelial NO synthase, cytochrome P450 (CYP450), erythropoietin receptor (EPOR); β-common receptor (βcR)), along with tobacco smoke modulation of microRNA-155 and aryl-hydrocarbon receptor (AHR) effects, may be important determinators of SARS-CoV-2 infection and COVID-19 course. While transient NO bioavailability increase and beneficial immunoregulatory modulations through the above-mentioned pathways using exogenous, endogenous, genetic and/or therapeutic modalities may have direct and specific, viricidal SARS-CoV-2 effects, employing tobacco smoke inhalation to achieve protection equals self-harm. Tobacco smoking remains the leading cause of death, illness, and impoverishment.

Association between Decreased Estimated Glomerular Filtration Rates and Long-term Mortality in Korean Patients with Acute Myocardial Infarction

A reduced estimated glomerular filtration rate (eGFR) is a predictor for mortality in patients with acute myocardial infarction (AMI). This study aimed to compare mortality according to the GFR and eGFR calculation methods during long-term clinical follow-ups. Using the Korean Acute Myocardial Infarction Registry-National Institutes of Health Data, 13,021 patients with AMI were included in this study. Patients were divided into the surviving (n=11,503, 88.3%) and deceased (n=1,518, 11.7%) groups. Clinical characteristics, cardiovascular risk factors, and 3-year mortality-related factors were analyzed. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) equations. The surviving group was younger than the deceased group (62.6±12.4 vs. 73.6±10.5 years, p<0.001), whereas the deceased group had higher hypertension and diabetes prevalences than the surviving group. A high Killip class was more frequently observed in the deceased group. eGFR was significantly lower in the deceased group (82.2±24.1 vs. 55.2±28.6 ml/min/1.73 m², p<0.001). Multivariate analysis revealed that low eGFR was an independent risk factor for mortality during the 3-year follow-up. The CKD-EPI equation was more useful for predicting mortality than the MDRD equation (0.766; 95% confidence interval [CI], 0.753-0.779 vs. 0.738; 95% CI, 0.724-0.753; p=0.001). Decreased renal function was a significant predictor of mortality after 3 years in patients with AMI. The CKD-EPI equation was more useful for predicting mortality than the MDRD equation.

The Impact of Smoking Status 1 Year After ST-Segment Elevation Myocardial Infarction on Cardiovascular Events and Mortality in Patients Aged ≤60 Years

Smoking is associated with increased risk for acute ST-elevation myocardial infarction (STEMI) at a young age. Although smoking is a modifiable risk factor, smoking cessation rates after STEMI are suboptimal. We investigated the association between smoking status 1 year after STEMI and adverse events in patients (n = 765) aged ≤60 years. Patients were categorized as: (1) nonsmokers, (2) quit smoking, and (3) continued/resumed smoking. The association between smoking status and risk for major adverse cardiovascular events (MACEs) was analyzed during a median follow-up of 8 years. At presentation with STEMI, the mean age was 51 ± 7 years (88% men) and 427 (56%) were smokers. A year after STEMI, 272 continued smoking, 35 quit but later resumed smoking (summed to a single group; n = 307), and 120 quit smoking. Continued smoking was associated with younger age, male gender, lower weight, and low socioeconomic status. Compared with nonsmokers, the adjusted hazard ratio (95% confidence interval) for myocardial infarction, stroke, unstable angina, death, and MACE was 2.51 (1.67 to 3.73), 2.07 (0.94 to 4.56), 3.73 (1.84 to 7.58), 2.52 (1.53 to 4.13), and 2.40 (1.80 to 3.22), accordingly, in those who continued to smoke. However, the adjusted hazard ratio was not significantly associated with these outcomes in patients who quit smoking (MACE: 1.20 [0.77 to 1.87], p=0.414; nonsignificant for individual end points). In conclusion, the prevalence of smoking in young and middle-aged patients presenting with STEMI is high and smoking cessation rates are low. A year after STEMI, those who continued to smoke had worse cardiovascular outcomes and death compared with nonsmokers; however, the long-term outcomes among those who quit smoking appear to be comparable with nonsmokers. The results highlight the contrast between health benefits of quitting smoking after STEMI and low abstinence rates in clinical practice.

Health-Related Quality of Life (HRQoL) of People over 65 Years of Age

Quality of life is an important indicator of the treatment process, lifestyle, and influence of many other factors, both exogenous and endogenous, on the body. Determining the quality of life of healthy people (health-related quality of life (HRQoL), considering the influence of various factors, is important due to the possibility of making subsequent comparative analyses regarding the quality of life of people diagnosed with diseases. In addition, it allows us to identify the most crucial factors influencing the HRQoL in the process of “good aging”. The purpose of the study was to present the HRQoL level of healthy people over 65 years of age. HRQoL was measured in five-year age groups (66–70, 71–75, 76–80, >80 years), considering the analyzed factors. Finally, 1038 healthy people were included in the study. The inclusion criteria were as follows: no diagnosed chronic diseases, no permanent treatment in specialist clinics, and no constant administration of medicaments. A comparative analysis was carried out, assuming a 5% conclusion error. The SF-36 questionnaire assessing the main dimensions of the quality of life was the tool used in the study to assess the HRQoL: the physical component summary (PCS), mental component summary (MCS) and index of life quality (ILQ). The factors significantly differentiating the average level of HRQoL were as follows: gender, place of residence, education, employment status, smoking and physical activity. Relationship status (p > 0.05) was one of the analyzed factors that did not influence the differences in the average level of the perceived HRQoL. More than a twofold greater chance of a higher HRQoL was reported in the group of men under 75 years of age (66–70: OR = 2.01; 71–75: OR = 2.52) compared to the group of women. The same relationship was noted in the case of higher education in respondents up to the age of 80 (66–70: OR = 1.56; 71–75: OR = 2.16; 76–80: OR = 2.74). Smoking by people over 80 years of age significantly increased the chances of a higher HRQoL in each of the dimensions (PCS: OR = 4.09; MCS: OR = 12.64; ILQ: OR = 5.79). Age as a non-modifiable factor significantly differentiates the level of the HRQoL of healthy people over 65 years of age. The results of the conducted study on HRQoL can be helpful when comparing the HRQoL of healthy people with a group of people with chronic diseases.

Impact of smoking on all-cause mortality and cardiovascular events in patients after coronary revascularization with a percutaneous coronary intervention or coronary artery bypass graft: a systematic review and meta-analysis

Although cigarette smoking is an independent risk factor for cardiovascular disease, inconsistent results have been published in the literature on its impacts on the cardiovascular health of patients after coronary revascularization with a percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG). We performed a comprehensive electronic database search through July 2018. Studies reporting the risk estimates of all-cause mortality and cardiovascular outcomes in patients after coronary revascularization with PCI or CABG on the basis of smoking status were selected. Multivariate-adjusted relative risks (RRs) and 95% confidence intervals (CIs) were pooled using random-effects models with inverse variance weighting. Data from 37 records including 126 901 participants were finally collected. Overall, the pooled RR (95% CI) associated with cigarette smoking was 1.26 (95% CI: 1.09-1.47) for all-cause mortality, 1.08 (95% CI: 0.92-1.28) for major adverse cardiovascular events, 0.96 (95% CI: 0.69-1.35) for cardiovascular mortality and 1.15 (95% CI: 0.81-1.64) for myocardial infarction. The increased risk of all-cause mortality was also observed in former smokers compared with those who had never smoked (RR: 1.19; 95% CI: 1.03-1.38). Furthermore, the negative effects of cigarette smoking on all-cause mortality were also observed in most subgroups. Cigarette smoking has been shown to increase the likelihood of all-cause mortality in patients after coronary revascularization with PCI or CABG. Smoking cessation is essential for PCI or CABG patients to manage their coronary artery disease.

The effects of smoking on adolescent trauma patients: a propensity-score-matched analysis

PURPOSE

Cigarettes have been demonstrated to be toxic to the pulmonary connective tissue by impairing the lung's ability to clear debris, resulting in infection and acute respiratory distress syndrome (ARDS). Approximately 8% of adolescents are smokers. We hypothesized that adolescent trauma patients who smoke have a higher rate of ARDS and pneumonia when compared to non-smokers.

METHODS

The Trauma Quality Improvement Program (2014-2016) was queried for adolescent trauma patients aged 13-17 years. Adolescent smokers were 1:2 propensity-score-matched to non-smokers based on age, comorbidities, and injury type. Data were analyzed using chi square for categorical data and Mann-Whitney U test for continuous data.

RESULTS

From 32,610 adolescent patients, 997 (3.1%) were smokers. After matching, 459 smokers were compared to 918 non-smokers. There were no differences in matched characteristics. Compared to non-smokers, smokers had an increased rate of pneumonia (3.1% vs. 1.1%, p = 0.01) but not ARDS (0.2% vs. 0%, p = 0.16). Compared to the non-smoking group, the smokers had a longer median total hospital length-of-stay (3 vs. 2 days, p = 0.01) and no difference in overall mortality (1.5% vs. 2.4%, p = 0.29).

CONCLUSION

Smoking is associated with an increased rate of pneumonia in adolescent trauma patients. Future research should target smoking cessation and/or interventions to mitigate the deleterious effects of smoking in this population.

Demystifying Smoker's Paradox: A Propensity Score-Weighted Analysis in Patients Hospitalized With Acute Heart Failure

Background Smoker's paradox has been observed with several vascular disorders, yet there are limited data in patients with acute heart failure (HF). We examined the effects of smoking in patients with acute HF using data from a large multicenter registry. The objective was to determine if the design and analytic approach could explain the smoker's paradox in acute HF mortality. Methods and Results The data were sourced from the acute HF registry (Gulf CARE [Gulf Acute Heart Failure Registry]), a multicenter registry that recruited patients over 10 months admitted with a diagnosis of acute HF from 47 hospitals in 7 Middle Eastern countries. The association between smoking and mortality (in hospital) was examined using covariate adjustment, making use of mortality risk factors. A parallel analysis was performed using covariate balancing through propensity scores. Of 5005 patients hospitalized with acute HF, 1103 (22%) were current smokers. The in-hospital mortality rates were significantly lower in current smoker's before (odds ratio, 0.71; 95% CI, 0.52-0.96) and more so after (odds ratio, 0.47; 95% CI, 0.31-0.70) covariate adjustment. With the propensity score-derived covariate balance, the smoking effect became much less certain (odds ratio, 0.63; 95% CI, 0.36-1.11). Conclusions The current study illustrates the fact that the smoker's paradox is likely to be a result of residual confounding as covariate adjustment may not resolve this if there are many competing prognostic confounders. In this situation, propensity score methods for covariate balancing seem preferable. Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01467973.

Clinical, Angiographic Characteristics and In-Hospital Outcomes of Smoker and Nonsmoker Patients After Primary Percutaneous Coronary Intervention

BACKGROUND

Smoking is a well-established cardiac risk factor there is dearth of Local data regarding clinical and angiographic characteristics of smoker patients.

OBJECTIVES

This study was planned to assess the differences in the clinical characteristics, angiographic characteristics, and in-hospital outcomes of smokers and nonsmokers after primary percutaneous coronary intervention at a tertiary care hospital in Karachi, Pakistan.

METHODS

We included patients between 40 and 80 years of age diagnosed with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention from July 1, 2017, to March 31, 2018. Clinical and angiographic characteristics and in-hospital outcomes were obtained from the cases submitted to the National Cardiovascular Data Registry's CathPCI (Catheterization-Percutaneous Coronary Intervention) Registry from our site.

RESULTS

A total of 3,255 patients were included in this study. Smokers consist of 25.1% (817) of the total sample. A high majority of smokers were male, 98.8% (807), and smokers were relatively younger as compared to nonsmokers with a mean age of 52.89 ± 10.59 versus 55.98 ± 11.24 years; p < 0.001. Smokers had higher post-procedure TIMI (Thrombolysis In Myocardial Infarction) flow grade III: 97.8% (794) versus 95.53% (2,329); p = 0.037, and they had a relatively low mortality rate: 2.69% (22) versus 3.16% (77); p = 0.502.

CONCLUSIONS

Smokers were predominantly male and around 3 years younger than nonsmokers. Diabetes mellitus and hypertension were less common among smokers and single-vessel disease was the more common angiographic finding for smokers as compared to 3-vessel disease for nonsmokers. No statistically significant differences in in-hospital outcomes were observed. ST-segment elevation myocardial infarction in smokers despite younger age and the low atherosclerotic risk profile, in our region, emphasize the need for nicotine addiction management and smoking cessation campaigns at large and for pre-discharge counseling.

Trends of Cardiac Complications in Patients With Rheumatoid Arthritis: Analysis of the United States National Inpatient Sample; 2005-2014

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory condition. Chronic inflammation is associated with atherosclerosis, hypertension, diabetes, chronic obstructive pulmonary disease (COPD), chronic kidney disease. But sparse data are available regarding the trends of cardiovascular diseases and complications in RA. We conducted a National Inpatient Sample database analysis to demonstrate the trends of cardiac complications in patients with RA.

METHODS

We used National Inpatient Sample data from 2005 to 2014 to identify admissions with the diagnosis of RA and identified who had associated cardiovascular complications also. The International Classification of Diseases-9th Revision-Clinical Modification codes were used for the diagnoses of RA; congestive heart failure (CHF), acute myocardial infarction (AMI), and atrial fibrillation (AF).

RESULTS

A statistically significant increasing trend of AMI, CHF, and AF was found. Independent predictors of mortality in RA patients with AMI were age (OR 1.03, CI 1.02-1.04; P < 0.001), COPD (OR 1.67, CI 1.40-2.00; P < 0.001), cerebrovascular disease (OR 2.207, CI 1.71-2.86; P < 0.001), renal disease (OR 1.42, CI 1.16-1.75; P = 0.001), and alcohol abuse (OR 2.73, CI 1.73-4.32; P < 0.001). Independent predictors of mortality in RA patients with CHF were age (odds ratio [OR] 1.02, confidence interval [CI] 1.017-1.024; P < 0.001]), COPD (OR 1.09, CI 1.01-1.18; P = 0.023), cerebrovascular disease (OR 1.67, CI 1.44-1.95; P < 0.001), renal disease (OR 1.16, CI 1.07-1.27; P = 0.001). Independent predictors of mortality in RA patients with AF were age (OR 1.02, CI 1.02-1.03; P < 0.001), race (OR 1.16, CI 1.02-1.31; P = 0.022), COPD (OR 1.56, CI 1.42-1.71; P < 0.001), peripheral arterial disease (OR 1.34, CI 1.16-1.53; P < 0.001), cerebrovascular disease (OR 2.27, CI 1.0-2.58; P < 0.001), renal disease (OR 1.60, CI 1.44-1.80; P < 0.001). The mortality trend has increased significantly in the CHF (P = 0.025) and AF (P = 0.042) groups during this study period.

CONCLUSIONS

We have found a significant increase in trend of cardiovascular complications in RA patients. The proportion of patients, with cardiovascular comorbidities, have also been increased significantly.

The impact of smoking on mortality after acute ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention: a retrospective cohort outcome study at 3 years

The "smoker's paradox", where smokers have improved survival post-myocardial infarction, was predominantly observed in the thrombolytic era. However, evidence for the smoker's paradox in the current era of PCI therapy is both limited and inconsistent. We aimed to examine the effect of smoking status on survival in unselected ST-elevation myocardial infarction (STEMI) patients managed by primary percutaneous coronary intervention (PCI). Data were collected for all patients with acute STEMI undergoing primary PCI at The South Yorkshire Cardiothoracic Centre, UK over a 5-year period between 2009 and 2014. Differences in survival by smoking status were assessed before and after adjustment for differences in baseline variables using a Kaplan-Meier curve and a Cox regression analysis, respectively. A total of 3133 STEMI patients were included in the study. After adjustment for differences in baseline variables, smoking was associated with a significantly increased mortality (hazard ratio 1.35 (95% CI 1.04-1.74)) compared to never smokers after 3 years. The risk for ex-smokers (hazard ratio 0.99 (0.76-1.28)) was similar to never smokers. There were no significant differences in survival by smoking status at 30 days and 1 year. In this large registry of STEMI patients managed by primary PCI, smokers had a significantly higher 3-year mortality than non-smokers. This study is the first to not only dispel the existence of the smoker's paradox, but to highlight a high-risk subgroup who may warrant tailored secondary prevention treatment, including smoking cessation.

The effect of smoking on residual platelet reactivity to clopidogrel: a systematic review and meta-analysis

Cigarette smoking is an important cardiovascular risk factor, causing morbidity and mortality. There are many original studies on the impact of smoking, but its influence on platelet ADP-P2Y12 receptor inhibitors lack consistency. Thus, we conducted a systematic review and meta-analysis of already existing data/studies to further explore this issue. PubMed, Web of science, EMBASE, Clinical Trials, and the Cochrane Library were searched from inception to March 2018. Studies investigating the residual platelet reactivity categorized by smoking status and patients treated with platelet ADP-P2Y12 receptor inhibitors qualified the inclusion criteria. The primary outcome was P2Y12 reaction unit (PRU) value measured by VerifyNow P2Y12 assay, compared with different smoking status in ADP-P2Y12 receptor inhibitors treatment groups. Secondary outcome was post-treatment with 5 μmol/L ADP-inhibition of platelet aggregation (ADP-IPA) measured by light transmittance aggregometry (LTA). Of the 4954 citations retrieved, 12 studies involving 16 296 patients with acute coronary syndrome and/or stent deployment using platelet ADP-P2Y12 receptor inhibitors were included for meta-analysis. Pooled analysis revealed that PRU values of current smokers were 25.70 lower than nonsmokers (95% CI -38.81 to -12.60, p = 0.0001), getting better effects of antiplatelet treatment. In the smoking extent subgroup analysis, patients smoking >10 cigarettes/day shown about 46.49 lower of PRU values than patients smoking <10 cigarettes/day (p < 0.00001). Racial subgroup analyses found that smokers had increased platelet inhibition in the Caucasian population. Further, pooled analysis of ADP-IPA values for 1658 patients from five studies showed a significantly lower residual platelet reactivity in current smokers compared to that in nonsmokers (MD = -4.19; 95% CI -6.55 to -1.83; p = 0.0005). This systematic review and meta-analysis suggested that smokers have increased platelet inhibition and lower aggregation in response to clopidogrel than nonsmokers. These residual platelet reactivity observations may help to explain differential clinical outcomes in smokers vs. nonsmokers in large scale clinical trials.

Characteristics and outcomes of in-hospital cardiac arrest in adults hospitalized with acute coronary syndrome in China

AIMS

This retrospective study aims to analyze and explore the clinical characteristics, risk factors, and in-hospital outcomes - including return of spontaneous circulation (ROSC) and survival to discharge - of hospitalized patients admitted with acute coronary syndrome (ACS) suffering cardiac arrest.

METHODS

ACS patients admitted to three tertiary hospitals in Fujian, China, were evaluated retrospectively from January 1, 2012 to December 30, 2016. Data were collected, based on the Utstein Style, for all cases of attempted resuscitation for IHCA. We analyzed patient characteristics, pre-event variables, event variables, and the main outcomes, including ROSC and survival to discharge, and identified the influencing factors on the outcomes.

RESULTS

The total number of ACS admissions across the three hospitals during this study period was 21,337. Among these admissions, 320 ACS patients experienced IHCA (incidence: 1.50%); 134 (41.9%) patients experienced ROSC; and 68 (21.2%) survived to discharge. The findings indicated that four factors were associated with ROSC, including age <70 years-old, shockable rhythm, duration of resuscitation (≤15 min and 16-30 min), and PCI. Five factors were associated with survival to discharge, including age <70 years-old, shockable rhythm, the duration of resuscitation (≤15 min and 16-30 min), Killip ≤ II, and CCI ≤ 2.

CONCLUSION

Younger age, shockable rhythm, and shorter duration of resuscitation were all factors demonstrated to be a predictor of ROSC and survival to hospital discharge.

Meta-Analysis Comparing Outcomes of Smokers Versus Nonsmokers With Acute Coronary Syndrome Underwent Percutaneous Coronary Intervention

Several studies have found improved mortality in smokers after acute coronary syndrome (ACS) especially in the thrombolytic era. We aimed to assess the association of smoking status with mortality and cardiovascular outcomes in patients with ACS treated with percutaneous coronary intervention (PCI). We searched PubMed, EMBASE, CINAHL, and Cochrane CENTRAL for randomized controlled trials since inception through February 15, 2018 and used random effects model for analysis. The outcomes analyzed were all-cause mortality, major adverse cardiac events (MACE), myocardial infarction, and target vessel revascularization at 1 month and 1 year. We included 17 randomized and nonrandomized studies with a total of 55,491 patients with 21,989 smokers' and 33,502 nonsmokers. In ACS patients treated with PCI, smokers were found to have lower mortality than nonsmokers at 30-day ([2.3% vs 3.3%; Odds ratio; 0.54; 95% confidence interval: 0.39 to 0.76; p <0.001, I² = 74%] and 1-year [2.3% vs 3.6%; Odds ratio 0.54 (0.3 to 0.7); p <0.001, I² = 77%]. Meta-regression showed lower mortality in smokers was associated with younger age, man gender, and lower prevalence of diabetes mellitus. No significant differences were observed in myocardial infarction, MACE, and target-vessel revascularization between smokers and nonsmokers. In conclusion, smoking is associated with lower mortality but not MACE in ACS patients treated with PCI at 1-month and 1-year. This association with mortality was strongly associated with younger age, man gender, prevalence of diabetes mellitus, and extent of coronary artery disease.

Effect of factor XIII levels and polymorphisms on the risk of myocardial infarction in young patients

Factor XIII (FXIII) stabilizes and protects the fibrin network. Its role in myocardial infarction (MI) is still to be clarified. To evaluate the association of FXIII levels with MI in young patients and to investigate how the FXIII-A p.Val34Leu, FXIII-B p.His95Arg, and IVS11, c.1952 + 144 C>G (Intron K) polymorphisms influence FXIII levels and MI risk. Patients with ST elevation MI below 40 years of age (MI, n = 119), age-matched clinical controls (CC, n = 101) without MI and coronary artery disease, and healthy controls (HC, n = 120) were investigated for FXIII activity, FXIII-A₂B₂, FXIII-B concentrations and for the polymorphisms. FXIII activity and FXIII-A₂B₂ antigen were significantly elevated in MI. FXIII activity and antigen were significantly elevated in Arg95, while decreased in Intron K "G" carriers. Smoking had an independent increasing effect on FXIII activity and FXIII-A₂B₂ antigen. Intron K C>G polymorphism significantly decreased the risk of MI in patients with elevated fibrinogen. Among the investigated factors Intron K C>G polymorphism and smoking have the most powerful effect on FXIII levels and on the risk of MI in the young. The effect of smoking on coronary thrombus formation may partially be attributed to its FXIII increasing effect.

Clinical characteristics and prognosis of acute myocardial infarction in young smokers and non-smokers (≤ 45 years): a systematic review and meta-analysis

The effect of smoking on the prognosis of young patients with acute myocardial infarction (AMI) is inconclusive. We enrolled 2188 young AMI patients (≤ 45 years) from the cardiac center of the Chinese PLA General Hospital and Anzhen Hospital and analyzed their clinical characteristics and prognosis. We also searched the PubMed, EMBASE, and Cochrane Central Register of Controlled Trials electronic databases for January 2001 to March 2017 and considered for inclusion in a meta-analysis those clinical trials that compared prognoses of young smokers and non-smokers with AMI. The proportion of males and alcohol users was higher in young AMI smokers than in non-smokers; the proportion of hypertension was slightly lower. There was no difference in medical treatment between smokers and non-smokers. No differences were evident between smokers and non-smokers regarding in-hospital cardiac events and major adverse cardiovascular events on follow-up, including incidence of stroke. For young AMI patients, smoking did not lead to poorer prognosisin comparison with not smoking. This “smoker's paradox” needs to be confirmed by more randomized controlled multicenter prospective clinical trials.

Smoking status and life expectancy after acute myocardial infarction in the elderly

OBJECTIVE

Smokers have lower short-term mortality after acute myocardial infarction (AMI) than non-smokers; however, little is known about the long-term effects of smoking on life expectancy after AMI. This study aimed to quantify the burden of smoking after AMI using life expectancy and years of life lost.

METHODS

We analysed data from the Cooperative Cardiovascular Project, a medical record study of 158,349 elderly Medicare patients with AMI and over 17 years of follow-up, to evaluate the age-specific association of smoking with life expectancy and years of life lost after AMI.

RESULTS

Our sample included 23,447 (14.8%) current smokers. Current smokers had lower crude mortality up to 5 years, which was largely explained by their younger age at AMI. After adjustment other patient characteristics, smoking was associated with lower 30-day (HR 0.91, 95% CI 0.87 to 0.94) but higher long-term mortality (17-year HR 1.19, 95% CI 1.17 to 1.20) after AMI. Overall, crude life expectancy estimates were lower for current smokers than non-smokers at all ages, which translated into sizeable numbers of life-years lost attributable to smoking. As age at AMI increased, the magnitude of life-years lost due to smoking decreased. After full risk adjustment, the differences in life expectancy between current smokers and non-smokers persisted at all ages.

CONCLUSIONS

Current smoking is associated with lower life expectancy and large numbers of life-years lost after AMI. Our findings lend additional support to smoking cessation efforts after AMI.

"Smoker's Paradox" in Patients Treated for Severe Injuries: Lower Risk of Mortality After Trauma Observed in Current Smokers

BACKGROUND

Studies evaluating the effect of smoking status on mortality outcomes in trauma patients have been limited, despite the fact that survival benefits of smoking have been reported in other critical care settings. The phenomenon "smoker's paradox" refers to the observation that following acute cardiovascular events, such as acute myocardial infarction and cardiac arrest, smokers often experience decreased mortality in the hospital setting. The objective of our study was to determine whether smoking imparts a survival benefit in patients with traumatic injuries.

METHODS

We performed a retrospective cohort study that analyzed cases included in the National Trauma Data Bank research dataset. Hierarchical logistic regression analyses were used to determine whether smoking alters the risk of mortality and complications in patients who smoke.

RESULTS

The percentage of patients experiencing mortality differed significantly between smokers (n = 38,564) and nonsmokers (n = 319,249) (1.8% vs. 4.3%, P < .001); however, the percentage experiencing a major complication did not (9.7% vs. 9.6%, P = .763). Regression analyses indicated that smokers were significantly less likely to die during the hospital stay compared to nonsmokers after adjusting for individual and hospital factors (OR = 0.15; CI = 0.10, 0.22). Additionally, smokers were also less likely to develop a major complication than nonsmokers (OR = 0.73, CI = 0.59-0.91).

CONCLUSIONS

Patients who smoke appear to have a much lower risk of in-hospital mortality than nonsmokers. Further investigation into biological mechanisms responsible for this effect should be carried out in order to potentially develop therapeutic applications.

The scientific achievements of the decades in Korean Acute Myocardial Infarction Registry

The Korea Acute Myocardial Infarction Registry (KAMIR) was the first nationwide registry data collection designed to track outcomes of patients with acute myocardial infarction (AMI). These studies reflect the current therapeutic approaches and management for AMI in Korea. The results of KAMIR could help clinicians to predict the prognosis of their patients and identify better diagnostic and treatment tools to improve the quality of care. The KAMIR score was proposed to be a predictor of the prognosis of AMI patients. Triple antiplatelet therapy, consisting of aspirin, clopidogrel and cilostazol, was effective at preventing major adverse clinical outcomes. Drug-eluting stents were effective and safe in AMI patients with no increased risk of stent thrombosis. Statin therapy was effective in Korean AMI patients, including those with very low levels of low density cholesterol. The present review summarizes the 10-year scientific achievements of KAMIR from admission to outpatient care during long-term clinical follow-up.

A history of smoking is associated with improved survival in patients treated with mild therapeutic hypothermia following cardiac arrest

OBJECTIVES

To assess the association between smoking and survival with a good neurologic outcome in patients following cardiac arrest treated with mild therapeutic hypothermia (TH).

METHODS

We conducted a retrospective observational study of a prospectively collected cohort of 188 consecutive patients following cardiac arrest treated with TH between May 2007 and January 2012. Smoking status was retrospectively collected via chart review and was classified as "ever" or "never". Primary endpoint was survival to hospital discharge with a good neurologic outcome and was compared between smokers and nonsmokers. Logistic regression analysis was used to assess the association between smoking status and neurologic outcome at hospital discharge; adjusting for age, initial rhythm, time to return of spontaneous circulation (ROSC), bystander CPR, and time to initiation of TH.

RESULTS

Smokers were significantly more likely to survive to hospital discharge with good neurologic outcome compared to nonsmokers (50% vs. 28%, p=0.003). After adjusting for age, initial rhythm, time to ROSC, bystander CPR, and time to initiation of TH, a history of smoking was associated with increased odds of survival to hospital discharge with good neurologic outcome (OR 3.54, 95% CI 1.41-8.84, p=0.007).

CONCLUSIONS

Smoking is associated with improved survival with good neurologic outcome in patients following cardiac arrest. We hypothesize that our findings reflect global ischemic conditioning caused by smoking.

Paradoxical association of smoking with in-hospital mortality among patients admitted with acute ischemic stroke

BACKGROUND

Compared to those who never smoked, a paradoxical effect of smoking on reducing mortality in patients admitted with myocardial ischemia has been reported. We sought to determine if this effect was present in patients hospitalized with ischemic stroke.

METHODS AND RESULTS

Using the local Get with the Guidelines-Stroke registry, we analyzed 4305 consecutively admitted ischemic stroke patients (March 2002-December 2011). The sample was divided into smokers versus nonsmokers. The main outcome of interest was the overall inpatient mortality. Compared to nonsmokers, tobacco smokers were younger, more frequently male and presented with fewer stroke risk factors such as hypertension, hyperlipidemia, diabetes, coronary artery disease, and atrial fibrillation. Smokers also had a lower average NIH Stroke Scale (NIHSS) and fewer received tissue plasminogen activator (tPA). Patients in both groups had similar adherence to early antithrombotics, dysphagia screening prior to oral intake, and deep vein thrombosis (DVT) prophylaxis. Smoking was associated with lower all-cause in-hospital mortality (6.6% versus 12.4%; unadjusted OR 0.46; CI [0.34 to 0.63]; P<0.001). In multivariable analysis, adjusted for age, gender, ethnicity, hypertension, diabetes mellitus, hyperlipidemia, CAD, atrial fibrillation, NIHSS, and tPA, smoking remained independently associated with lower mortality (adjusted OR 0.64; CI [0.42 to 0.96]; P=0.03).

CONCLUSIONS

Similar to myocardial ischemia, smoking was independently associated with lower inpatient mortality in acute ischemic stroke. This effect may be due to tobacco-induced changes in cerebrovascular vasoreactivity, or may be due in part to residual confounding. Larger, multicenter studies are needed to confirm the finding and the effect on 30-day and 1-year mortality.