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AimWe assessed the management and outcomes of non-ST segment elevation myocardial infarction (NSTEMI) patients randomly assigned to fractional flow reserve (FFR)-guided management or angiography-guided standard care.Methods and resultsWe conducted a prospective, multicentre, parallel group, 1 : 1 randomized, controlled trial in 350 NSTEMI patients with ≥1 coronary stenosis ≥30% of the lumen diameter assessed visually (threshold for FFR measurement) (NCT01764334). Enrolment took place in six UK hospitals from October 2011 to May 2013. Fractional flow reserve was disclosed to the operator in the FFR-guided group (n = 176). Fractional flow reserve was measured but not disclosed in the angiography-guided group (n = 174). Fractional flow reserve ≤0.80 was an indication for revascularization by percutaneous coronary intervention (PCI) or coronary artery bypass surgery (CABG). The median (IQR) time from the index episode of myocardial ischaemia to angiography was 3 (2, 5) days. For the primary outcome, the proportion of patients treated initially by medical therapy was higher in the FFR-guided group than in the angiography-guided group [40 (22.7%) vs. 23 (13.2%), difference 95% (95% CI: 1.4%, 17.7%), P = 0.022]. Fractional flow reserve disclosure resulted in a change in treatment between medical therapy, PCI or CABG in 38 (21.6%) patients. At 12 months, revascularization remained lower in the FFR-guided group [79.0 vs. 86.8%, difference 7.8% (−0.2%, 15.8%), P = 0.054]. There were no statistically significant differences in health outcomes and quality of life between the groups.ConclusionIn NSTEMI patients, angiography-guided management was associated with higher rates of coronary revascularization compared with FFR-guided management. A larger trial is necessary to assess health outcomes and cost-effectiveness.

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Devonian black shales deposited on the North American craton contain abundant Tasmanites cysts that are typically preserved as flattened circular discs on bedding planes. Work by the present authors shows that cysts can be preserved as pyrite-infill casts that are expressed as sand-size whole and geopetal half-spheres of pyrite. At the bases of thin black shale layers these occur in situ at many stratigraphic levels in the distal prodelta facies of the Catskill Delta complex of New York, as well as in laterally equivalent black shales in Tennessee and Kentucky. Reworked pyrite casts, usually dominated by whole spheres, form lenticular lag accumulations and hydraulic placers, together with plant debris and phosphatic particles (bone debris, conodonts). An earlier model for the formation of pyrite spheres in gas bubbles is rejected in favor of formation within uncompressed Tasmanites cysts. Direct observation of cyst cuticle in association with pyrite spheres suggests that localized bacterial sulfate reduction in Tasmanites interior voids led to formation of localized pyrite deposition, in a manner similar to that described from certain ammonoid chamber settings. Cyst fill commenced with formation of framboidal pyrite, followed by later diagenetic pyrite cementation between framboids. These fills show geopetal features and appear to have formed within the redox zone below the sediment-water interface. Although described here from the Upper Devonian, comparable pyrite textures are also known from Proterozoic, Cambrian, Ordovician, and Silurian sediments. They probably occur throughout the sedimentary record, and in mudstone successions they may prove to be an important source of sand-size grains in areas far removed from the basin margins. As such they may be important for detection of erosive events and strong bottom currents, and provide valuable information about the depositional history of mudstone successions.

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