"Smoking paradox" is not true in patients with ischemic stroke: a systematic review and meta-analysis

The impact of smoking on third-degree atrioventricular block outcomes: A propensity-matched analysis

Background

Third-degree atrioventricular (AV) blocks are rare but cause significant symptoms and require immediate intervention. Coronary artery disease (CAD) is felt to be the most common etiology. Although smoking is a prominent risk factor for CAD, there is a paucity of data assessing the direct effect of smoking on third-degree AV block.

Methods

We performed a retrospective cohort study on adult-weighted admissions in 2019-2020 with a primary diagnosis of third-degree AV block and a history of smoking using the National Inpatient Sample (NIS) database. In-hospital mortality, rates of pacemaker insertion, cardiogenic shock, cardiac arrest, acute kidney injury (AKI), stroke, tracheal intubation, mechanical ventilation, mechanical circulatory support, vasopressor use, length of stay (LOS), and total hospitalization costs were analyzed using regression analysis. We performed a secondary analysis using propensity score matching to confirm the results.

Results

A total of 77,650 admissions met inclusion criteria (33,625 females [43.3 %], 58,315. Caucasians [75 %], 7030 African American [9 %], 6155 Hispanic [7.9 %]; mean [SD] age 75.4.[10.2] years) before propensity matching. A total of 29,380 (37.8 %) patients with AV block were smokers.A total of 5560 patients with and without a history of smoking were matched for the analysis. Smokers had.decreased odds of mortality (aOR, 0.59; CI, 0.44-0.78; p < 0.001), cardiogenic shock, cardiac arrest, tracheal intubation, mechanical ventilation, shorter LOS, and lower total hospital costs in both the multivariable regression and propensity-matched analyses.

Conclusion

Third-degree AV block had lower in-hospital mortality, cardiogenic shock, cardiac arrest, LOS, and total hospitalization cost in patients with smoking history.

Impact of smoking on one year functional outcomes after thrombectomy for young stroke patients

BACKGROUND

The incidence of stroke in young patients (20-50 years old) has increased in recent decades. Unlike the use of good functional outcomes to evaluate prognosis, excellent functional outcomes are a better indicator of return to work among younger patients. The rate of return to work increases with time after stroke. This study investigated the short term (3 months) and long term (1 year) predictors of excellent functional outcomes in young patients after endovascular thrombectomy (EVT).

METHODS

We included young patients who underwent EVT for acute ischemic stroke (AIS) due to large vessel occlusion within 6 hours after stroke onset between 2015 and 2021. Patients with intracerebral hemorrhage on pretreatment CT were excluded. The associations between clinical, imaging, and procedure variables, and excellent functional outcomes were analyzed using univariate and multivariable logistic regression analyses. An excellent functional outcome was defined as a modified Rankin Scale score of ≤1.

RESULTS

Of the 361 patients with AIS eligible for EVT, 55 young patients (aged 24-50 years) were included. Of these, 36.4% and 41.8% achieved excellent functional outcomes at 3 and 12 months, respectively. Multivariate analysis revealed that smoking was the independent negative predictor of both 3 month (adjusted OR (aOR) 0.232, 95% CI 0.058 to 0.928; p=0.039) and 12 month (aOR 0.180, 95% CI 0.044 to 0.741; p=0.018) excellent functional outcomes.

CONCLUSIONS

Current or former smoking habit was an independent negative predictor of both short term and long term excellent functional outcomes in young adults with AIS.

Revisiting the Smoking Paradox in Acute Ischemic Stroke Patients: Findings From the Chinese Stroke Center Alliance Study

Background Smoking is a well-established risk factor for the development of acute ischemic stroke (AIS). However, the "smoker's paradox" suggests that it is associated with favorable clinical outcomes following stroke. We aimed to reevaluate the association between smoking and in-hospital outcomes in patients with AIS in contemporary practice. Methods and Results A total of 649 610 inpatients with AIS from 1476 participating hospitals in the Chinese Stroke Center Alliance were included. In-hospital outcomes measurement included all-cause mortality, discharge against medical advice, and complications. Multivariable logistic regression models adjusting for baseline characteristics, clinical profiles at presentation, and in-hospital management were used to evaluate the association between smoking and in-hospital outcomes. A propensity score-matched analysis was also conducted. Of these patients with AIS, 36.8% (n=238 912) were smokers. Smokers were younger, had fewer comorbidities, and had slightly lower rates of adverse in-hospital outcomes than nonsmokers (all-cause death or discharge against medical advice: 6.0% versus 6.1%; in-hospital complications: 14.5% versus 15.1%). Multivariable analysis revealed that smoking was associated with higher risk of adverse in-hospital outcomes (all-cause death or discharge against medical advice: odds ratio [OR], 1.05 [95% CI, 1.02-1.08]; P<0.001; complications: OR, 1.06 [95% CI, 1.04-1.08]; P<0.001). The excess risk of adverse in-hospital outcomes remained in smoking patients with AIS after propensity score-matching analysis (all-cause death or discharge against medical advice: OR, 1.04 [95% CI, 1.00-1.08]; P=0.034; complications: OR, 1.05 [95% CI, 1.03-1.08]; P<0.001). Conclusions Smoking was associated with increased risk of adverse in-hospital outcomes among patients with AIS in contemporary practice, reinforcing the importance of smoking cessation in patients with AIS.

Resolving the Smoking Paradox: No Evidence for Smoking-Induced Preconditioning in Large Vessel Occlusion Stroke

INTRODUCTION

Smoking is an established risk factor for stroke. However, several studies have reported a better outcome after stroke for patients who smoke. According to this "smoking paradox" hypothesis, smoking might promote less severe strokes, higher collateral scores, and smaller infarct cores.

METHODS

In this retrospective study, we screened data of 2,980 acute ischemic stroke patients with MCA-M1 occlusion treated with mechanical thrombectomy. Patients were categorized according to smoking status (current, former, or never). We assessed univariate associations between clinical characteristics and smoking status. Subsequently, we used adjusted regression analysis to evaluate associations of smoking with stroke severity on admission (National Institutes of Health Stroke Scale [NIHSS]; primary endpoint), infarct core volume, and collateral status (secondary endpoints).

RESULTS

Out of 320 patients, 19.7% (n = 63) were current smokers and 18.8% (n = 60) were former smokers. Admission NIHSS, reperfusion success, and modified Rankin Scale (mRS) after 3-6 months were similar in all groups. Current smokers were younger, more often male and less likely to have atrial fibrillation compared to former and never smokers. In regression analyses, smoking status was neither associated with admission NIHSS (estimate 0.54, 95% confidence interval [CI]: -1.27-2.35, p = 0.557) nor with collateral status (estimate 0.79, 95% CI: 0.44-1.44, p = 0.447) or infarct core volume (estimate -0.69, 95% CI: -15.15-13.77, p = 0.925 for current vs. never smokers).

CONCLUSION

We could not confirm the smoking paradox. Our results support the fact that smoking causes stroke at a younger age, highlighting the role of smoking as a modifiable vascular risk factor.

Smoking Affects the Post-Stroke Inflammatory Response of Lipid Mediators in a Gender-Related Manner

The main goal of our study was to determine the effect of cigarette smoking on selected derivatives of arachidonic acid, linoleic acid, DHA, and EPA, which may be markers of post-stroke inflammation. The eicosanoid profile was compared in both smoking and non-smoking patients, without division and with division into gender. In the group of non-smokers, we observed higher levels of the linolenic acid derivative (LA) 9S HODE (p ≤ 0.05) than in smokers. However, after dividing the results by sex, it turned out that the level of this derivative was higher in non-smoking women compared to smoking women (p ≤ 0.01) and did not differentiate the group of men. Similarly, the level of the arachidonic acid metabolite LTX A4 (p ≤ 0.05) differed only in the group of women. In this group, we also observed a decreased level of 15S HETE in smoking women, but it was statistically insignificant (p ≤ 0.08). On the other hand, the level of this derivative was statistically significantly higher in the group of non-smoking women compared to male non-smokers. The group of men was differentiated by two compounds: TXB2 and NPD1. Male smokers had an almost two-fold elevation of TXB2 (p ≤ 0.01) compared with non-smokers, and in this group, we also observed an increased level of NPD1 compared with male non-smokers. On the other hand, when comparing female non-smokers and male non-smokers, in addition to the difference in 15S HETE levels, we also observed elevated levels of TXB2 in the group of non-smokers. We also analyzed a number of statistically significant correlations between the analyzed groups. Generally, men and women smokers showed a much smaller amount of statistically significant correlations than non-smokers. We believe that this is related to the varying degrees of inflammation associated with acute ischemic stroke and post-stroke response. On the one hand, tobacco smoke inhibits the activity of enzymes responsible for the conversion of fatty acids, but on the other hand, it can cause the failure of the inflammatory system, which is also the body's defense mechanism. Smoking cigarettes is a factor that increases oxidative stress even before the occurrence of a stroke incident, and at the same time accelerates it and inhibits post-stroke repair mechanisms. This study highlights the effect of smoking on inflammation in both genders mediated by lipid mediators, which makes smoking cessation undeniable.

Age Stratification in Acute Ischemic Stroke Patients with Heart Failure

Background and Purpose. Heart failure (HF) is considered one of the major risk factors associated with the severity of acute ischemic stroke(AIS). The risk factors associated with stroke severity in AIS with a history of HF is not fully understood. Methods. A prospectively maintained database from comprehensive stroke centers in PRISMA Health Upstate Sc, was analyzed for patients with AIS and a history of HF from January 2010 to 30 June 2016. The primary outcome was risk factors associated with a National Institute of Health Stroke Scale score (NIHSS) < 7 indicating lower severity and a score ≥ 7 indicating high severity for 65−74 age category and ≥75 years age category for AIS-HF patients. Univariate analysis was used to determine risk factors based on age categories and stroke severities, while multivariable analysis was used to adjust for the effect of confounding variables. Results: A total 367 AIS-HF patients were identified in this study, 113 patients were between 65−74 years old, while 254 patients were in the ≥75 years old age category. In the adjusted analysis for 65−74 age category, history of smoking (OR = 0.105, 95% Confidence interval (CI): 0.018−0.614, p = 0.012), triglycerides (Odd ratio(OR) = 0.993, 95% (CI): 0.987−0.999, p = 0.019), and International Normalized Ratio (INR) (OR = 0.454, 95% CI: 0.196−1.050, p = 0.045), and direct admission treatment (OR = 0.355, 95% CI: 0.137−0.920, p = 0.033) were associated with a lower stroke severity, elevated heart rate (OR = 1.032, 95% CI: 1.009−1.057, p = 0.007) was associated with a higher stroke severity. For the ≥75 years old age category, previous stroke (OR = 2.297, 95% CI: 1.171−9.852, p = 0.024), peripheral vascular disease (OR = 6.784, 95% CI: 1.242−37.065, p = 0.027), heart rate (OR = 1.035, 95% CI: 1.008−1.063, p = 0.012), and systolic blood pressure (OR = 1.023, 95% CI: 1.005−1.041, p = 0.012) were associated with a higher severe stroke severity. Conclusions: After adjusting for the effect of potential confounders, more risk factors were associated with a high severity of stroke among ≥75 years old compared with 65−74 years old AIS-HF patients. Elevated heart rate was an independent risk factor associated with stroke severity in 65−74 and ≥75 years old AIS-HF patients. Elevated heart rate and other identified risk factors should be managed to reduce stroke severity among elderly AIS-HF patients.

Juvenile patients with the homozygous MTHFR C677T genotype develop ischemic stroke 5 years earlier than wild type

To compare age at 1st ischaemic stroke (IS) in a cohort of juvenile (< 46 years of age) IS patients evaluated for the rs1801133 polymorphism (C → T677) of the methylene tetrahydrofolate reductase (MTHFR) gene; to identify predictors of age at IS and of type of cerebral vessel involvement, small vessel disease (SVD) vs large vessel disease (LVD) responsible for the IS; to evaluate possible associations between other clinical and laboratory variables. Retrospective cohort study on 82 MTHFR TT, 54 MTHFR TC and 34 MTHFR CC participants; data regarding age, sex, age at IS, history of dyslipidaemia, hypertension, smoking, migraine and homocysteine (HC) as well as neuroimaging were collected. Age at IS was lower in MTHFR TT than MTHFR TC and CC (35 ± 4 vs 38 ± 0 vs 40 ± 3 years, respectively, p = 0.002); plasma HC (median, interquartile range) was higher in MTHFR TT than in the other groups [16.7 (11.8, 28.6) vs 11.4 (8.2, 16.1) vs 9.8 (7.9, 1.3) respectively, p < 0.0001)] and was higher in SVD than LVD [17.4 (12.4, 32.5) vs  11.4 (8.8, 16.4) p < 0.0001]. MTHFR TT independently predicted age at IS (p = 0.0008) alongside smoking both as a categorical (p = 0.003) or continuous variable (p = 0.02), whereas HC independently predicted SVD as categorical (p = 0.01) and continuous variable (p < 0.0001). Smoking positively predicted plasma HC (p = 0.005) and negatively the activated partial thromboplastin ratio (aPTTr) (p = 0.02). Juvenile IS carriers of the MTHFR TT genotype develop their 1st occlusion on average 5 years earlier compared to the CC genotype; smoking contributes to this prematurity adversely affecting plasma HC and coagulation whereas plasma HC predicts IS secondary to SVD. Public health campaigns against smoking should highlight the prematurity of IS in the juvenile population.

Stroke associated with Mycoplasma hominis infection: a case report

BACKGROUND

Mycoplasmas are the smallest prokaryotic microorganisms in nature. Many cases of stroke post-Mycoplasma pneumoniae infection have been reported, particularly in the pediatric population. However, Mycoplasma hominis infection has not previously been associated with stroke.

CASE PRESENTATION

We report the case of a 36-year-old Greek woman who presented with an extensive stroke with an unspecified cause. She had a concurrent genital infection with Mycoplasma hominis for an unknown duration.

CONCLUSION

An association may exist between stroke and the immune response to Mycoplasma hominis infection.

Smoking influences outcome in patients who had thrombolysed ischaemic stroke: the ENCHANTED study

Background and purpose

As studies vary in defining the prognostic significance of smoking in acute ischaemic stroke (AIS), we aimed to determine the relation of smoking and key outcomes in patient participants who had thrombolysed AIS of the international quasi-factorial randomised Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED).

Methods

Post-hoc analyses of ENCHANTED, an international quasi-factorial randomised evaluation of intravenous alteplase-dose comparison and levels of blood pressure control in patients who had thrombolysed AIS. Multivariable logistic regression models with inverse probability of treatment weighting (IPTW) propensity scores were used to determine associations of self-reported smoking status and clinical outcomes, according to 90-day modified Rankin Scale (mRS) scores and symptomatic intracerebral haemorrhage (sICH).

Results

Of 4540 patients who had an AIS, there were 1008 (22.2%) current smokers who were younger and predominantly male, with more comorbidities of hypertension, coronary artery disease, atrial fibrillation and diabetes mellitus, and greater baseline neurological impairment, compared with non-smokers. In univariate analysis, current smokers had a higher likelihood of a favourable shift in mRS scores (OR 0.88, 95% CI 0.77 to 0.99; p=0.038) but this association reversed in a fully adjusted model with IPTW (adjusted OR 1.15, 95% CI 1.04 to 1.28; p=0.009). A similar trend was also apparent for dichotomised poor outcome (mRS scores 2–6: OR 1.18, 95% CI 1.05 to 1.33; p=0.007), but not with the risk of sICH across standard criteria.

Conclusion

Smoking predicts poor functional recovery in patients who had thrombolysed AIS.

Trial registration number

NCT01422616.

Effects of White Matter Hyperintensities on 90-Day Functional Outcome after Large Vessel and Non-Large Vessel Stroke

INTRODUCTION

White matter hyperintensity (WMH) burden is a critically important cerebrovascular phenotype related to the diagnosis and prognosis of acute ischemic stroke. The effect of WMH burden on functional outcome in large vessel occlusion (LVO) stroke has only been sparsely assessed, and direct LVO and non-LVO comparisons are currently lacking.

MATERIAL AND METHODS

We reviewed acute ischemic stroke patients admitted between 2009 and 2017 at a large healthcare system in the USA. Patients with LVO were identified and clinical characteristics, including 90-day functional outcomes, were assessed. Clinical brain MRIs obtained at the time of the stroke underwent quantification of WMH using a fully automated algorithm. The pipeline incorporated automated brain extraction, intensity normalization, and WMH segmentation.

RESULTS

A total of 1,601 acute ischemic strokes with documented 90-day mRS were identified, including 353 (22%) with LVO. Among those strokes, WMH volume was available in 1,285 (80.3%) who had a brain MRI suitable for WMH quantification. Increasing WMH volume from 0 to 4 mL, age, female gender, a number of stroke risk factors, presence of LVO, and higher NIHSS at presentation all decreased the odds for a favorable outcome. Increasing WMH above 4 mL, however, was not associated with decreasing odds of favorable outcome. While WMH volume was associated with functional outcome in non-LVO stroke (p = 0.0009), this association between WMH and functional status was not statistically significant in the complete case multivariable model of LVO stroke (p = 0.0637).

CONCLUSION

The burden of WMH has effects on 90-day functional outcome after LVO and non-LVO strokes. Particularly, increases from no measurable WMH to 4 mL of WMH correlate strongly with the outcome. Whether this relationship of increasing WMH to worse outcome is more pronounced in non-LVO than LVO strokes deserves additional investigation.