3-D magnetic resonance angiography versus conventional angiography in peripheral arterial disease: Pilot study

Angiography is usually performed as the preoperative road map for those requiring revascularization for lower extremity peripheral arterial disease (PAD). The alternative investigations are ultrasound, 3-D magnetic resonance angiography (3-D MRA) and computed tomography angiography. This pilot study aimed to assess whether 3-D MRA could replace the gold standard angiography in preoperative planning. Eight patients considered for aortoiliac or infrainguinal arterial bypass surgery were recruited. All underwent both imaging modalities within 7 days. A vascular surgeon and a radiologist each reported on the images from both the 3-D MRA and the angiography, with blinding to patient details and each others reports. Comparisons were made between the reports for the angiographic and the 3-D MRA images, and between the reports of the vascular surgeon and the radiologist. Compared to the gold standard angiogram, 3-D MRA had a sensitivity of 77% and specificity of 94% in detecting occlusion, and a sensitivity of 72% and specificity of 90% in differentiating high grade (> 50%) versus low grade (< 50%) stenoses. There was an overall concordance of 78% between the two investigations with a range of 62% in the peroneal artery to 94% in the aorta. 3-D MRA showed flow in 23% of cases where conventional angiography showed no flow. In the present pilot study, 3-D MRA had reasonable concordance with the gold standard angiography, depending on the level of the lesion. At times it showed vessel flow where occlusion was shown on conventional angiogram. 3-D MRA in peripheral vascular disease is challenging the gold standard, but is inconsistent at present.

Arterial heparan sulfate proteoglycans inhibit vascular smooth muscle cell proliferation and phenotype change in vitro and neointimal formation in vivo

Purpose: The aim of this study was to determine whether heparan sulfate proteoglycans (HSPGs) from the normal arterial wall inhibit neointimal formation after injury in vivo and smooth muscle cell (SMC) phenotype change and proliferation in vitro. Methods: Arterial HSPGs were extracted from rabbit aortae and separated by anion-exchange chromatography. The effect of HSPGs, applied in a periadventitial gel, on neointimal formation was assessed 14 days after balloon catheter injury of rabbit carotid arteries. Their effect on SMC phenotype and proliferation was measured by point-counting morphometry of the cytoplasmic volume fraction of myofilaments (Vvmyo) and H-3-thymidine incorporation in SMCs in culture. Results: Arterial HSPGs (680 mu g) reduced neointimal formation by 35% at 14 days after injury (P =.029), whereas 2000 mu g of the low-molecular-weight heparin Enoxaparin was ineffective. HSPGs at 34 mu g/mL maintained subconfluent primary cultured SMCs with the same high Vvmyo (52.1% +/- 13.8%) after 5 days in culture as did cells freshly isolated from the arterial wall (52.1% +/- 15.1%). In contrast, 100 mu g/mL Enoxaparin was ineffective in preventing phenotypic change over this time period (Vvmyo 38.9% +/- 14.6%, controls 35.9% +/- 12.8%). HSPGs also inhibited 3H-thymidine incorporation into primary cultured SMCs with an ID50 value of 0.4 mu g/mL compared with a value of 14 mu g/ml; for Enoxaparin (P

International tourists and road safety in Australia: developing a national research and management programme

Motor vehicle crashes are the leading cause of injury death for international tourists. This makes road safety an important issue for tourism authorities. Unfortunately, as it is in other areas of tourist health, the common response from the travel and tourism industry is to remain silent about this problem and to leave any mishaps in the hands of insurers. At the same time, but for different reasons, international tourists are not usually targeted for road safety initiatives by transport authorities. Given that there are considerable 'hidden' costs associated with international tourists and motor vehicle crashes, the topic should be of concern to both tourism and transport groups. This paper examines issues concerned with driving in unfamiliar surroundings for international visitors in Australia, and proposes a national research and management programme to guide policy and planning in the area. (C) 1999 Elsevier Science Ltd. All rights reserved.

Vascular smooth muscle and arterial calcification

Smooth muscle cultures can calcify under certain circumstances. As a model system these cultures therefore provide information on why calcification occurs in atherosclerotic plaques. Whether all smooth muscle cells (under certain conditions), or only specific populations, can produce this mineralization has not been resolved. Demer's group has cloned calcifying vascular cells from subcultured bovine aorta and studied them in detail. They have speculated on whether the cells are smooth muscle which have altered in phenotype, or whether they are derived from a stem cell population within the artery wall. The article argues that while the normal process of smooth muscle phenotypic modulation seen in arterial repair could account for the observations, this view may be two simplistic considering the complex nature of the artery wall. Certainly there is evidence for heterogeneity of smooth muscle cells in the artery wall and recent evidence suggests that stem cells can circulate in the blood and repopulate tissues. Further studies are required to resolve the important question as to the origin of cells which produce mineralization in atheroma.

Improving maximum walking distance in early peripheral arterial disease: Randomised controlled trial

The purpose of this study was to determine the impact of increased physical activity and cessation of smoking on the natural history of early peripheral arterial disease, We conducted a randomised controlled trial in Perth, Western Australia, involving 882 men with early peripheral arterial disease identified via population-based screening using the Edinburgh Claudication Questionnaire and the ankle:brachial index. Members of the control group (n = 441) received usual care from their general practitioner while members of the intervention group (n = 441) were allocated to a stop smoking and keep walking regime - a combined community-based intervention of cessation of smoking (where applicable) and increased physical activity. Postal follow-up occurred at two and 12 months post-entry into the trial. The main outcome of interest was maximum walking distance. There were no statistically significant differences in the characteristics of the intervention and usual care groups at recruitment. Follow-up information at two and 12 months was available for 85% and 84% of participants, respectively. At 12 months, more men allocated to the intervention group had improved their maximum walking distance (23% vs 15%; chi(2) = 9.74, df = 2, p = 0.008). In addition, more men in the intervention group reported walking more than three times per week for recreation (34% vs 25%, p = 0.01). Although not statistically significant, more men in the intervention group who were smokers when enrolled in the trial had stopped smoking (12% vs 8%, p = 0.43). It is concluded that referral of older patients with intermittent claudication to established physiotherapy programs in the community can increase levels of physical activity and reduce disability related to peripheral arterial disease. A combination of simple and safe interventions that are readily available in the community through physiotherapists and general practitioners has the potential to improve early peripheral arterial disease.

In Australia are people born in other countries at higher risk of road trauma than locally born people?

This study examined whether people born in other countries had higher rates of death and hospitalization due to road crashes than people born in Australia. Data on deaths that occurred in the whole of Australia between 1994 and 1997 and hospitalizations that occurred in the state of New South Wales, Australia, between I July 1995 and 30 June 1997 due to road crashes were analyzed. The rates of death and hospitalization, adjusted for age and area of residence, were calculated using population data from the 1996 Australian census. The study categorized people born in other countries according to the language (English speaking, non-English speaking) and the road convention (left-hand side, right-hand side) of their country of birth. Australia has the left-hand side driving convention. The study found that drivers born in other countries had rates of death or hospitalization due to road trauma equal to or below those of Australian born drivers. In contrast, pedestrians born in other countries, especially older pedestrians had higher rates of death and hospitalization due to road crashes. Pedestrians aged 60 years or more born in non-English speaking countries where traffic travels on the right-hand side of the road had risks about twice those of Australian born pedestrians in the same age group. (C) 2003 Elsevier Ltd. All rights reserved.

Positive end expiratory pressure during resuscitation of premature lambs rapidly improves blood gases without adversely affecting arterial pressure

Positive end expiratory pressure (PEEP) is important for neonatal ventilation but is not considered in guidelines for resuscitation. Our aim was to investigate the effects of PEEP on cardiorespiratory parameters during resuscitation of very premature lambs delivered by hysterotomy at similar to125 d gestation (term similar to147 d). Before delivery, they were intubated and lung fluid was drained. Immediately after delivery, they were ventilated with a Drager Babylog plus ventilator in volume guarantee mode with a tidal volume of 5 mL/kg. Lambs were randomized to receive 0, 4, 8, or 12 cm H2O of PEEP. They were ventilated for a 15-min resuscitation period followed by 2 h of stabilization at the same PEEP. Tidal volume, peak inspiratory pressure, PEEP, arterial pressure, oxygen saturation, and blood gases were measured regularly, and respiratory system compliance and alveolar/ arterial oxygen differences were calculated. Lambs that received 12 cm H2O of PEEP died from pneumothoraces; all others survived without pneumothoraces. Oxygenation was significantly improved by 8 and 12 cm H2O of PEEP compared with 0 and 4 cm H2O of PEEP. Lambs with 0 PEEP did not oxygenate adequately. The compliance of the respiratory system was significantly higher at 4 and 8 cm H2O of PEEP than at 0 PEEP. There were no significant differences in partial pressure of carbon dioxide in arterial blood between groups. Arterial pressure was highest with 8 cm H2O of PEEP, and there was no cardiorespiratory compromise at any level of PEEP. Applying PEEP during resuscitation of very premature infants might be advantageous and merits further investigation.

Prevalence of peripheral arterial disease: persistence of excess risk in former smokers

Objective: To determine the age-standardised prevalence of peripheral arterial disease (PAD) and associated risk factors, particularly smoking. Method: Design: Cross-sectional survey of a randomly selected population. Setting: Metropolitan area of Perth, Western Australia. Participants: Men aged between 65-83 years. Results: The adjusted response fraction was 77.2%. Of 4,470 men assessed, 744 were identified as having PAD by the Edinburgh Claudication Questionnaire and/or the ankle-brachial index of systolic blood pressure, yielding an age-standardised prevalence of PAD of 15.6% (95% confidence intervals (CI): 14.5%, 16.6%). The main risk factors identified in univariate analyses were increasing age, smoking current (OR=3.9, 95% CI 2.9-5.1) or former (OR=2.0, 95% CI 1.6-2.4), physical inactivity (OR=1.4, 95% CI 1.2-1.7), a history of angina (OR=2.2, 95% CI 1.8-2.7) and diabetes mellitus (OR=2.1, 95% CI 1.7-2.6). The multivariate analysis showed that the highest relative risk associated with PAD was current smoking of 25 or more cigarettes daily (OR=7.3, 95% CI 4.2-12.8). In this population, 32% of PAD was attributable to current smoking and a further 40% was attributable to past smoking by men who did not smoke currently. Conclusions: This large observational study shows that PAD is relatively common in older, urban Australian men. In contrast with its relationship to coronary disease and stroke, previous smoking appears to have a long legacy of increased risk of PAD. Implications: This research emphasises the importance of smoking as a preventable cause of PAD.