Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy

Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme

Session 17 Ecophysiology

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The effect of industrial air pollution on membrane lipid composition of Scots pine [Pinus sylvestris L.] needles

This work was undertaken to determine lipids changes in needles of Scots pine (Pinus sylvestris L.) populations growning on polluted stands near a phosphate fertilizer factory in Luboń, and copper smelter in Głogów and in a control area in Kórnik. Needles from polluted areas had a lower content of total phospholipids than samples from the unpolluted site. Greater changes were detected in membranes of needles collected in October and January. In comparison with the control total phospholipid in needles of populations from polluted areas were 14 to 33% lower. Phosphatidylcholine (PC) phosphatidylethanolamine (PE) and phosphatidylglicerol (PG) were the dominant phospholipids. The analysis of fatty acids in phospholipid fraction showed a decrease of linoleic acid (18:2) and linolenic acid (18:3) contents. The level of polyunsaturated fatty acids in needles of three populations from polluted areas was up to 40% lower as compared with the control. Moreover, phospholipids and their fatty acids showed seasonal fluctuations. The contents of PC, PG and PE increased in autumn and in winter, during the process of cold acclimation. In July, current-year needles did not show significant differences in membrane lipid composition between the polluted areas of Scots pine populations. The results suggest that the lipid changes of needles could be associated with disturbances in phohospholipid metabolism, caused by environmental pollution

Environmental pollution changes in membrane lipids, antioxidants and vitality of Scots pine [Pinus sylvestris L.] pollen

Investigations were carried out on pollen grains of Scots pine (Pinus sylvestris L.) collected from trees at 1.5, 3, 4 km and control, 20 km from the Luboń factory producing mineral fertilisers. The percentage of germination of pollen formed close to the pollution source was ca 20% lower compared to the control pollen. Lowered vitality of the pollen was effected in changes of the structure of cytoplasmic membranes. Pollen from the polluted area contained ca 15% less total phospholipids, mainly phosphatidylcholine and phosphatytidylinositol and had a lower content of soluble proteins and less of low molecular antioxidants, such as thiols and ascorbic acid. Composition of total fatty acid in phospholipids fractions showed a significant reduction in the degree of unsaturation of fatty acids. Pollen originating from the polluted area and stored at -30°C showed considerably stronger degradation of cytoplasmic membranes than control