Abstract-Physical inactivity is a potent stimulus for vascular remodeling, leading to a marked decrease in conduit artery diameter. However, little is known about the impact of physical inactivity on artery wall thickness or wall:lumen ratio or the potential of exercise countermeasures to modify artery wall thickness. The purpose of the study was to examine the impact of 60 days of bed rest, with or without exercise countermeasures, on carotid and superficial femoral artery wall thickness. Eighteen men were assigned to bed rest (second Berlin Bed Rest Study) and randomly allocated to control, resistive exercise, or resistive vibration exercise. Both exercise countermeasures were applied 3 times per week while the subjects were in the supine position on the bed. Sonography was used to examine baseline diameter and wall thickness of the carotid and femoral arteries. Bed rest decreased diameter of the superficial femoral artery (Pϭ0.001) but not the carotid artery (Pϭ0.29). Bed rest induced a significant increase in carotid and superficial femoral artery wall thickness (Pϭ0.007 and 0.03) and wall:lumen ratio (Pϭ0.009 and 0.001). Exercise prevented the increase in wall thickness of the carotid artery. In addition, exercise partly prevented the increased wall:lumen ratio in the superficial femoral artery. In conclusion, 8 weeks of bed rest resulted in Ϸ20% increase in conduit artery wall thickness. Exercise countermeasures completely (carotid artery) or partly (superficial femoral artery) abolished the increase in wall thickness. These findings suggest that conduit artery wall thickness, a vascular characteristic associated previously with atherosclerosis, can rapidly adapt to physical inactivity and exercise in humans. (Hypertension. 2010;56:240-246.)
Bed rest results in marked vascular adaptations, and resistive vibration exercise (RVE) has been shown to be an effective countermeasure. As vibration exercise has practical and logistical limitations, the use of resistive exercise (RES) alone has the preference under specific circumstances. However, it is unknown if RES is sufficient to prevent vascular adaptations to bed rest. Therefore, the purpose of the present study was to examine the impact of RES and RVE on the vascular function and structure of the superficial femoral artery in young men exposed to 60 days of bed rest. Eighteen healthy men (age: 31 +/- 8 yr) were assigned to bed rest and randomly allocated to control, RES, or RVE groups. Exercise was applied 3 times/wk for 5-7 min/session. Resting diameter, blood flow, flow-mediated dilation (FMD), and dilator capacity of the superficial femoral artery were measured using echo-Doppler ultrasound. Bed rest decreased superficial femoral artery diameter and dilator capacity (P < 0.001), which were significantly attenuated in the RVE group (P < 0.01 and P < 0.05, respectively) but not in the RES group (P = 0.202 and P = 0.696, respectively). Bed rest significantly increased FMD (P < 0.001), an effect that was abolished by RVE (P < 0.005) but not RES (P = 0.078). Resting and hyperemic blood flow did not change in any of the groups. Thus, RVE abolished the marked increase in FMD and decrease in baseline diameter and dilator capacity normally associated with prolonged bed rest. However, the stimulus provided by RES alone was insufficient to counteract the vascular adaptations to bed rest.
To determine the cost-effectiveness of middleear implantations in hearing-impaired patients with severe external otitis in the Netherlands. Design: Cost-effectiveness analysis, using singlesubject repeated measures of quality of life and total cost determinations. Setting: Hospital based. Patients: Moderately to severely sensorineurally hearingimpaired patients (n = 21) with severe chronic external otitis, eligible to receive a middle-ear implant. Main Outcome Measure: Cost per quality-adjusted life-year (QALY), based on scores of the Medical Outcomes Study Short-Form Health Survey (SF-36) generic quality of life questionnaire. Only direct costs were included in cost calculation of middle-ear implantation. Results: Mean health utility gain was 0.046 (0.012-0.079) (P=.01) measured at the mental component of the SF-36. With a mean profitable time of 19.4 years and an overall cost of €14 354, minimal cost-effectiveness of middle-ear implantation was €16 085/QALY. Conclusion: Based on the cost per QALY, middle-ear implantation proved to be a cost-effective and justified health care intervention in the Netherlands.
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