Attenuated severity of new acute ischemic events in patients with previous coronary heart disease receiving long-acting nitrates

Cigarette Smoking Is Related to Endothelial Dysfunction of Resistance, but Not Conduit Arteries in the General Population-Results From the Gutenberg Health Study

Aims: Cigarette smoking is one of the most complex and least understood cardiovascular risk factors. Importantly, differences in the tobacco-related pathophysiology of endothelial dysfunction, an early event in atherogenesis, between circulatory beds remain elusive. Therefore, this study evaluated how smoking impacts endothelial function of conduit and resistance arteries in a large population-based cohort.

Methods and results: 15,010 participants (aged 35–74 years) of the Gutenberg Health Study were examined at baseline from 2007 to 2012. Smoking status, pack-years of smoking, and years since quitting smoking were assessed by a computer-assisted interview. Endothelial function of conduit and resistance arteries was determined by flow-mediated dilation (FMD) of the brachial artery, reactive hyperemia index (RHI) using peripheral arterial tonometry, as well as by reflection index (RI) derived from digital photoplethysmography, respectively. Among all subjects, 45.8% had never smoked, 34.7% were former smokers, and 19.4% were current smokers. Mean cumulative smoking exposure was 22.1 ± 18.1 pack-years in current smokers and mean years since quitting was 18.9 ± 12.7 in former smokers. In multivariable linear regression models adjusted for typical confounders, smoking status, pack-years of smoking, and years since quitting smoking were independently associated with RHI and RI, while no association was found for FMD. Overall, no clear dose-dependent associations were observed between variables, whereby higher exposure tended to be associated with pronounced resistance artery endothelial dysfunction.

Conclusions: Cigarette smoking is associated with altered endothelial function of resistance, but not conduit arteries. The present results suggest that smoking-induced endothelial dysfunction in different circulatory beds may exhibit a differential picture.

Association between clinical presentations before myocardial infarction and coronary mortality: a prospective population-based study using linked electronic records

Background

Ischaemia in different arterial territories before acute myocardial infarction (AMI) may influence post-AMI outcomes. No studies have evaluated prospectively collected information on ischaemia and its effect on short- and long-term coronary mortality. The objective of this study was to compare patients with and without prospectively measured ischaemic presentations before AMI in terms of infarct characteristics and coronary mortality.

Methods and results

As part of the CALIBER programme, we linked data from primary care, hospital admissions, the national acute coronary syndrome registry and cause-specific mortality to identify patients with first AMI (n = 16,439). We analysed time from AMI to coronary mortality (n = 5283 deaths) using Cox regression (median 2.6 years follow-up), comparing patients with and without recent ischaemic presentations. Patients with ischaemic presentations in the 90 days before AMI experienced lower coronary mortality in the first 7 days after AMI compared with those with no prior ischaemic presentations, after adjusting for age, sex, smoking, diabetes, blood pressure and cardiovascular medications [HR: 0.64 (95% CI: 0.57–0.73) P < 0.001], but subsequent mortality was higher [HR: 1.42 (1.13–1.77) P = 0.001]. Patients with ischaemic presentations closer in time to AMI had the lowest seven day mortality (P-trend = 0.001).

Conclusion

In the first large prospective study of ischaemic presentations prior to AMI, we have shown that those occurring closest to AMI are associated with lower short-term coronary mortality following AMI, which could represent a natural ischaemic preconditioning effect, observed in a clinical setting.

Clinical trials registration

Clinicaltrials.gov identifier NCT01604486.

[Meta-analysis of the scientific evidence on the usefulness of sporadic intake of acetylsalicylic acid in the prevention of coronary heart disease]

BACKGROUND

The present study was aimed at determining whether the sporadic intake of acetylsalicylic acid (ASA) shows a protective effect on the appearance or attenuation of coronary disease events.

METHODS

The analysis was based on articles found in EMBASE, MEDLINE and the Cochrane Library. Scientific rigour was further assessed. We looked for original articles with clinical trial, cohorts, and case-control or cross-sectional study designs, where the effect could be assessed by the odds ratio (OR).

RESULTS

A meta-analysis showed a protective effect of sporadic ASA intake on the prevention of acute myocardial infarction (OR for fixed effects = 0.75, CI 95%, 0.63-0.88, p < 0.0006), which was more important in men than in women, and on the prevention of cardiovascular mortality (OR for fixed effects = 0.61, CI 95%, 0.59-0.64, p < 0.0001). However, overall mortality was found to be higher in those groups receiving the drug (OR for fixed effects = 1.20, CI 95%, 1.05-1.37, p = 0.0006). None of these effects was significant when performing a random effect analysis. ASA also attenuated acute coronary syndromes (OR for fixed effects = 0.34, CI 95%, 0.26-0.45, p < 0.0001).

CONCLUSIONS

These results suggest that the sporadic intake of ASA may have a protective particularly in men and attenuating effect on acute myocardial infarction, in addition to playing a role in preventing cardiovascular mortality but not overall mortality. Further studies to confirm these effects are warranted.

Isosorbide dinitrate inhibits platelet adhesion and aggregation in nonthrombolyzed patients with acute myocardial infarction

BACKGROUND

Apart from their vasodilatatory properties, nitrates have been shown to inhibit platelet aggregation. The effects of nitrates on platelet adhesion have not been studied. Nonselected patients with acute myocardial infarction (AMI) have been suggested to gain no benefit from administration of nitrates. However, the importance of nitrates may be greater in a subgroup of nonthrombolyzed patients with AMI.

HYPOTHESIS

Isosorbide dinitrate (ISDN) decreases platelet adhesion and aggregation in nonthrombolyzed patients with AMI.

METHODS

Consecutive 48 men with AMI, not eligible for thrombolytic therapy because of late presentation (> 12 h), were prospectively randomized 2:1 to double-blind ISDN (mean dose 2.4 +/- 0.9 mg/h) (n = 33) or placebo (0.9% sodium chloride) (n = 15) infusion. All patients received aspirin. Blood samples were taken at baseline (no study medication) and 3 h into ISDN or placebo infusion. Platelet adhesion to collagen was measured in the ethylene diamine tetraacetic acid (EDTA)-platelet rich plasma by recording changes in light transmission with an optical aggregometer. Platelet aggregation was measured using the Born's method.

RESULTS

Isosorbide dinitrate significantly decreased both platelet adhesion and aggregation. No effect was seen in the placebo group.

CONCLUSIONS

In patients with AMI who do not receive thrombolytic therapy, ISDN effectively inhibits platelet adhesion and aggregation. These effects of nitrates may be of therapeutic and prognostic significance in this group of patients.