Eicosanoid biosynthesis in patients with stable angina: Beneficial effects of very low dose aspirin

AbstractObjectives. We assessed the production of eicosanoids and the effects of very low dose aspirin in patients with stable angina under basal conditions and during rapid atrial pacing.Background. Platelet activation occurs in acute ischemic syndromes but is still controversial in stable angina. Very low dose aspirin is known to be platelet selective and can be used to test the hypothesis of the platelet origin of increased thromboxane production in stable angina.Methods. Urinary excretion of eicosanoids was measured in 42 patients, including 24 patients with and 18 patients without coronary artery disease. The effects of 50 mg/day of aspirin were measured at rest and during pacing-induced ischemia in 10 patients with stable angina and were compared with a similar group of patients not treated by aspirin.Results. Excretion of 11-dehydro-thromboxane B2was 2.6 times higher in patients with stable angina than in healthy subjects (mean [±SEM] 74.8 ± 13.0 [24 patients] vs. 29.0 ± 5.4 [18 patients] ng/mmol of creatinine, p < 0.01). Urinary prostacyclin metabolite levels did not differ between the two groups. Treatment for 8 days with 50 mg/day of aspirin inhibited platelet cyclooxygenase, as reflected by the 97% reduction of in vitro serum thromboxane production. This aspirin regimen normalized the level of urinary thromboxane metabolites in patients with angina (17.3 ± 3.4 ng/mmol of creatinine [10 patients], p < 0.001 from baseline level before treatment) and did not change prostacyclin metabolite levels. Atrial pacing in patients with angina not treated with aspirin caused lactate and thromboxane release into the coronary sinus. In patients with very low dose aspirin therapy, pacing did not cause thromboxane release despite inducing myocardial ischemia. However, fractional lactate extraction decreased less sharply in patients with than without aspirin therapy.Conclusions. Thromboxane production is greatly increased in patients with stable angina. Very low dose aspirin administered to these patients reduces thromboxane synthesis to normal levels, preserves prostacyclin biosynthesis and prevents acute thromboxane release into the coronary circulation during pacing-induced ischemia. Our data suggest that platelets (not monocytes/ macrophages) are activated in stable angina to produce thromboxane

A resilience lens to explore seaweed farmers’ responses to the impacts of climate change in Tanzania

Seaweed-based mariculture is an important source of livelihoods for impoverished coastal communities in Tanzania. However, the impacts of climate change across East Africa are putting a strain on the growth of the seaweed industry. Smallholder farmers are already mobilizing strategies to cope with challenges such as disease outbreaks, but they are struggling to maintain seaweed production and derive sufficient income. A better understanding of the challenges they face and the factors inhibiting their ability to build resilience is needed to inform policies and development programmes to achieve the Sustainable Development Goals, particularly Goal 13 on Climate action and Goal 14 on Life Below Water. The global demand for seaweed is expanding rapidly. Strengthening the adaptability of seaweed production to climate change is important for farmers to rely on it as a source of livelihoods on which they can build their own resilience to climate change. Drawing on qualitative data from key informant interviews in four Tanzanian seaweed-producing areas, this paper assesses the long-term resilience capacities of seaweed farmers to respond to one of the main hazards: diseases affecting seaweed crops. While several strategies help farmers maintain their income, most of them only support resilience in the short term. The increasing pressure on marine resources and the lack of regulations for supporting an equitable and sustainable seaweed-based mariculture sector do not bode well for farmers’ long-term adaptation to climate change and environmental degradation. Seaweed farming remains a crucial source of livelihoods for poor coastal communities in Tanzania, but it does not currently lead to positive transformative changes in their socio-economic conditions. Policies aiming to support sustainable aquaculture, particularly in tropical ecosystems that are highly vulnerable to climate change, must address the existing social, economic and knowledge inequities that prevent poor communities from building their resilience

Prevalence of obstructive coronary artery disease and prognosis in patients with stable symptoms and a zero-coronary calcium score

© The Author 2017. Published by Oxford University Press on behalf of the European Society of Cardiology.Aims: CT calcium scoring (CTCS) and CT cardiac angiography (CTCA) are widely used in patients with stable chest pain to exclude significant coronary artery disease (CAD). We aimed to resolve uncertainty about the prevalence of obstructive coronary artery disease and long-term outcomes in patients with a zero-calcium score (ZCS). Methods and results: Consecutive patients with stable cardiac symptoms referred for CTCS or CTCS and CTCA from chest pain clinics to a tertiary cardiothoracic centre were prospectively enrolled. In those with a ZCS, the prevalence of obstructive CAD on CTCA was determined. A follow-up for all-cause mortality was obtained from the NHS tracer service. A total of 3914 patients underwent CTCS of whom 2730 (69.7%) also had a CTCA. Half of the patients were men (50.3%) with a mean age of 56.9 years. Among patients who had both procedures, a ZCS was present in 52.2%, with a negative predictive value of 99.5% for excluding ≥70% stenosis on CTCA. During a mean follow-up of 5.2 years, the annual event rate was 0.3% for those with ZCS compared with 1.2% for CS ≥1. The presence of non-calcified atheroma on CTCA in patients with ZCS did not affect the prognostic value (P = 0.98). Conclusion: In patients with stable symptoms and a ZCS, obstructive CAD is rare, and prognosis over the long-term is excellent, regardless of whether non-calcified atheroma is identified. A ZCS could reliably be used as a 'gatekeeper' in this patient cohort, obviating the need for further more expensive tests.Peer reviewedFinal Published versio

Observational study of adherence to European clinical practice guidelines for the management of acute coronary syndrome in revascularized versus non-revascularized patients – the CONNECT Study

SummaryBackgroundThe CONNECT study compared clinician adherence to guideline-recommended secondary prevention therapies prescribed at discharge for patients hospitalized for acute coronary syndrome (ACS) in those managed initially with percutaneous coronary intervention (PCI; revascularized) and those who did not undergo revascularization.MethodsPatients aged greater than or equal to 18 years, hospitalized for a documented ST-segment elevation or non-ST-segment elevation ACS, were enrolled consecutively over 1 month at 238 sites in France.ResultsCompared with revascularized patients (n=870), non-revascularized patients (n=706) were significantly older, and a greater proportion were women, had high-blood pressure, type-2 diabetes or a history of atherothrombotic or cardiac disease, but a smaller proportion had a history of coronary angioplasty. On discharge, non-revascularized patients were prescribed beta-blockers, aspirin, statins, angiotensin-converting enzyme inhibitors or adenosine diphosphate receptor antagonists less frequently than revascularized patients. An adherence score greater than or equal to 80% (at least four of the five recommended agents prescribed at discharge) was found in 96.7% of revascularized patients and 74.4% of non-revascularized patients (P<0.001).ConclusionsDespite a similar or even higher level of cardiovascular risk, non-revascularized ACS patients were prescribed guideline-recommended secondary prevention therapy less frequently than revascularized patients