A myocardial perfusion reserve index derived from first-pass MRI studies can distinguish between normal subjects and patients with coronary artery disease. Furthermore, it provides useful functional information on coronary lesions, particularly where the physiologic significance cannot be predicted accurately from the angiogram.

No abstract

This technology appraisal guidance should be read in conjunction with the NICE interventional procedure guidance on stent-graft placement in abdominal aortic aneurysm (interventional procedure guidance 163). 2 EVAR is recommended as a treatment option for patients with unruptured infra-renal abdominal aortic aneurysms, for whom surgical intervention (open surgical repair or endovascular aneurysm repair) is considered appropriate.The decision on whether EVAR is preferred to open surgical repair should be made jointly by the patient and his/her clinician after assessment of a number of factors including: c aneurysm size and morphology c patient age, general life expectancy and fitness for open surgery c the short-term and long-term benefits and risks of the procedures including aneurysm-related mortality and operative mortality. EVAR should only be performed in specialist centres by clinical teams experienced in the management of abdominal aortic aneurysms and with appropriate expertise in all aspects of patient assessment and the use of endovascular aortic stent-grafts.Endovascular aortic stent-grafts are not recommended for patients with ruptured aneurysms except in the context of research. DEVELOPMENT OF THE GUIDANCEThe appraisal committee first considered the evidence on the clinical effectiveness of EVAR for the treatment of unruptured infra-renal abdominal aortic aneurysms. Four randomised controlled trials (RCTs) were identified 3-8 comparing EVAR with open surgical repair (OSR) and three registries, 9-14 which indicated that EVAR had benefits in terms of reduced rates of operative and aneurysmrelated mortality in the medium term. However, these findings were not accompanied by a reduction in all-cause mortality and were associated with increased rates of complications and reinterventions for EVAR compared with OSR.Evidence from clinical specialists indicated that the RCTs included in the analyses had used older stent-grafts, and that these stent-grafts had significantly improved since the RCTs were carried out. In addition, clinical expertise both in assessing patients' suitability for EVAR and in undertaking the procedure had improved with more widespread use of EVAR and therefore the rates of long-term aneurysm-related death, complications and reintervention following EVAR currently seen in UK clinical practice was lower than those shown in the RCTs. The appraisal committee was therefore persuaded that the benefits of EVAR compared with OSR in current UK clinical practice were likely to be greater than those seen in the RCTs.Evidence to support possible differences in the clinical effectiveness of the different types of stentgrafts was also considered. Only two of the five endovascular stent-grafts (Zenith and Talent) had been compared head-to-head in RCTs, 15 and these studies showed no statistically significant differences between these stent-grafts. Additionally, clinical specialists provided testimony that different stent-grafts were considered clinically comparable and that, in practice, any of the e...

The responses of circulating catecholamines, TSH, thyroid hormones and prolactin to 30 min of acute cold exposure (4 degrees C) were measured in eight normal volunteers over a 2 h period. There was a rise in circulating noradrenaline, TSH, T4 and T3 levels and a fall in circulating prolactin in the subjects studied, but no change in circulating adrenaline levels nor any alteration in the T4/T3 ratio. The thyroid axis of normal individuals can respond rapidly to acute cold exposure. In addition, the increased plasma noradrenaline levels accompanied by unaltered adrenaline levels suggest that the stimulus exerted by cold does not evoke a generalised stress response, but rather that the sympathetic nervous system is selectively stimulated.