Brachial artery ultrasound is commonly employed for noninvasive assessment of endothelial function. However, analysis is observer dependent and susceptible to errors. We describe studies on a computerized edge-detection and wall-tracking software program to allow more accurate and reproducible measurement. In study 1, three purpose-built Perspex phantom arteries, 3.00, 4.00, and 6.00 mm in diameter, were measured with the software. There was a mean bias of 11 microm (P < 0.001 at each level) between known and measured values; the mean resolving power of the software was estimated as 8.3 microm. In study 2, the mean intraobserver coefficient of variation of repeated measures of flow-mediated dilation (FMD) using the software (6.7%) was significantly lower than that for traditional manual measurements using the intima-lumen interfaces (24.8%, P < 0.05) and intima-media interfaces (32.5%, P < 0.05). In study 3, 24 healthy volunteers underwent repeat testing twice within 1 wk; the coefficients of variation for between-visit reproducibility of FMD and response to glyceryl trinitrate using the software were 14.7 and 17.6%, respectively. Assuming 80% power and an alpha of 0.05, eight subjects with matched controls would be required, in a parallel designed study, to detect an absolute 2.5% change in FMD. In summary, we have developed a semiautomated computerized vascular ultrasound analysis system that will improve the power of clinical intervention studies to detect small changes in arterial diameter.

If endothelial dysfunction is an integral component of the pathogenesis of vascular disease, as currently believed, this study supports the value of an exercise program in the management of type 2 diabetes.

No abstract

Exercise training of a muscle group improves local vascular function in subjects with chronic heart failure (CHF). We studied forearm resistance vessel function in 12 patients with CHF in response to an 8-wk exercise program, which specifically excluded forearm exercise, using a crossover design. Forearm blood flow (FBF) was measured using strain-gauge plethysmography. Responses to three dose levels of intra-arterial acetylcholine were significantly augmented after exercise training when analyzed in terms of absolute flows (7.0 +/- 1.8 to 10.9 +/- 2.1 ml x 100 ml(-1) x min(-1) for the highest dose, P < 0.05 by ANOVA), forearm vascular resistance (21.5 +/- 5.0 to 15.3 +/- 3.9 ml x 100 ml forearm(-1) x min(-1), P < 0.01), or FBF ratios (P < 0.01, ANOVA). FBF ratio responses to sodium nitroprusside were also significantly increased after training (P < 0.05, ANOVA). Reactive hyperemic flow significantly increased in both upper limbs after training (27.9 +/- 2.7 to 33.5 +/- 3.1 ml x 100 ml(-1) x min(-1), infused limb; P < 0.05 by paired t-test). Exercise training improves endothelium-dependent and -independent vascular function and peak vasodilator capacity in patients with CHF. These effects on the vasculature are generalized, as they were evident in a vascular bed not directly involved in the exercise stimulus.

Objective. Cardiovascular disease (CVD) is the leading disease burden in Aboriginal Australians, but culturally appropriate cardiac rehabilitation programs are lacking. We evaluated the uptake and effects on lifestyle, and cardiovascular risk factors, of cardiac rehabilitation at an Aboriginal Medical Service (AMS).Methods. The program involved weekly exercise and education sessions (through 'yarning') for Aboriginal people with or at risk of CVD. Participants' perceptions of the program and the impact on risk factors were evaluated following 8 weeks of attendance.Results. In twenty-eight participants (20 females) who completed 8 weeks of sessions, body mass index (34.0 AE 5.1 v. 33.3 AE 5.2 kg m -2 ; P < 0.05), waist girth (113 AE 14 v. 109 AE 13 cm; P < 0.01) and blood pressure (135/78 AE 20/12 v. 120/72 AE 16/5 mmHg; P < 0.05) decreased and 6-min walk distance increased (296 AE 115 v. 345 AE 135 m; P < 0.01). 'Yarning' helped identify and address a range of chronic health issues including medication compliance, risk factor review and chest pain management.Conclusions. AMS-based cardiac rehabilitation was well attended, and improved cardiovascular risk factors and health management. An AMS is an ideal location for managing cardiovascular health and provides a setting conducive to addressing a broad range of chronic conditions.What is known about the topic? Cardiovascular disease is the leading cause of morbidity and mortality in Aboriginal Australians, but less than 5% of eligible Aboriginal people attend hospital-based cardiac rehabilitation.