SummaryBackgroundRemote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months.MethodsWe did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed.FindingsBetween Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91–1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed.InterpretationRemote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI.FundingBritish Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden.

Inhalation of diesel exhaust increases ex vivo thrombus formation and causes in vivo platelet activation in man. These findings provide a potential mechanism linking exposure to combustion-derived air pollution with the triggering of acute MI.

AimExposure to road traffic and air pollution may be a trigger of acute myocardial infarction, but the individual pollutants responsible for this effect have not been established. We assess the role of combustion-derived-nanoparticles in mediating the adverse cardiovascular effects of air pollution.Methods and resultsTo determine the in vivo effects of inhalation of diesel exhaust components, 16 healthy volunteers were exposed to (i) dilute diesel exhaust, (ii) pure carbon nanoparticulate, (iii) filtered diesel exhaust, or (iv) filtered air, in a randomized double blind cross-over study. Following each exposure, forearm blood flow was measured during intra-brachial bradykinin, acetylcholine, sodium nitroprusside, and verapamil infusions. Compared with filtered air, inhalation of diesel exhaust increased systolic blood pressure (145 ± 4 vs. 133 ± 3 mmHg, P< 0.05) and attenuated vasodilatation to bradykinin (P= 0.005), acetylcholine (P= 0.008), and sodium nitroprusside (P< 0.001). Exposure to pure carbon nanoparticulate or filtered exhaust had no effect on endothelium-dependent or -independent vasodilatation. To determine the direct vascular effects of nanoparticulate, isolated rat aortic rings (n= 6–9 per group) were assessed in vitro by wire myography and exposed to diesel exhaust particulate, pure carbon nanoparticulate and vehicle. Compared with vehicle, diesel exhaust particulate (but not pure carbon nanoparticulate) attenuated both acetylcholine (P< 0.001) and sodium-nitroprusside (P= 0.019)-induced vasorelaxation. These effects were partially attributable to both soluble and insoluble components of the particulate.ConclusionCombustion-derived nanoparticulate appears to predominately mediate the adverse vascular effects of diesel exhaust inhalation. This provides a rationale for testing environmental health interventions targeted at reducing traffic-derived particulate emissions.

Background-In controlled human exposure studies, diesel engine exhaust inhalation impairs vascular function and enhances thrombus formation. The aim of the present study was to establish whether an exhaust particle trap could prevent these adverse cardiovascular effects in men. Methods and Results-Nineteen healthy volunteers (mean age, 25Ϯ3 years) were exposed to filtered air and diesel exhaust in the presence or absence of a particle trap for 1 hour in a randomized, double-blind, 3-way crossover trial. Bilateral forearm blood flow and plasma fibrinolytic factors were assessed with venous occlusion plethysmography and blood sampling during intra-arterial infusion of acetylcholine, bradykinin, sodium nitroprusside, and verapamil. Ex vivo thrombus formation was determined with the use of the Badimon chamber. Compared with filtered air, diesel exhaust inhalation was associated with reduced vasodilatation and increased ex vivo thrombus formation under both low-and high-shear conditions. The particle trap markedly reduced diesel exhaust particulate number (from 150 000 to 300 000/cm 3 to 30 to 300/cm 3 ; PϽ0.001) and mass (320Ϯ10 to 7.2Ϯ2.0 g/m 3 ; PϽ0.001), and was associated with increased vasodilatation, reduced thrombus formation, and an increase in tissue-type plasminogen activator release. Conclusions-Exhaust particle traps are a highly efficient method of reducing particle emissions from diesel engines. With a range of surrogate measures, the use of a particle trap prevents several adverse cardiovascular effects of exhaust inhalation in men. Given these beneficial effects on biomarkers of cardiovascular health, the widespread use of particle traps on diesel-powered vehicles may have substantial public health benefits and reduce the burden of cardiovascular disease. Clinical Trial Registration-http://www.clinicaltrials.gov. Unique identifier: NCT00745446. (Circulation. 2011;123:1721-1728.) Key Words: air pollution Ⅲ endothelium Ⅲ thrombosis T here is a robust and consistent association between air pollution and cardiorespiratory morbidity and mortality. [1][2][3][4] These harmful effects are most strongly associated with exposure to traffic-derived fine particles (particulate matter [PM] with a mean diameter Ͻ2.5 m [PM 2.5 ]) that originate predominantly from diesel engine exhaust emissions. 5 Diesel engines are popular because of their reliability, efficiency, and relatively low running costs. However, they generate up to 100 times more fine particles than petroleum engines of a similar size and contribute substantially to the global burden of PM air pollution. Editorial see p 1705 Clinical Perspective on p 1728According to the World Health Organization, air pollution is responsible for at least 800 000 premature deaths worldwide each year, with an average loss of life of 1 year. 6 The long-term risk of cardiovascular death rises by 76% for each 10-g/m 3 increase in PM 2.5 . 7,8 Short-term exposure has been linked to the triggering of acute myocardial infarction, 9 with patients 3 times more likely to be expo...