Simulator training on pulsatile vascular models significantly improves surgical skills and the quality of carotid patch plasty.

OBJECTIVE: Vascular surgeons perform numerous highly sophisticated and delicate procedures. Due to restrictions in training time and the advent of endovascular techniques, new concepts including alternative environments for training and assessment of surgical skills are required. Over the past decade, training on simulators and synthetic models has become more sophisticated and lifelike. This study was designed to evaluate the impact of a 3-day intense training course in open vascular surgery on both specific and global vascular surgical skills. METHODS: Prospective observational cohort analysis with various parameter measurements of both surgical skills and the technical quality of the finished product, performed before and after 3 days of simulator training of 10 participants (seven male and three female) in a vascular surgery training course. The simulator model used was a conventional carotid endarterectomy with a Dacron patch plasty on a lifelike carotid bench model under pulsatile pressure. The primary end points were assessment of any changes in the participants' surgical skills and in the technical quality of their completed carotid patches documented by procedure-based assessment forms. Scores ranging from 1 (inadequate) to 5 (excellent) were compared by a related-sample Wilcoxon signed test. Interobserver reliability was estimated by Cronbach's alpha (CA). RESULTS: A significant improvement in surgical skills tasks was observed (P < .001). The mean score increased significantly by 21.5% from fair (3.43 ± 0.93) to satisfactory (4.17 ± 0.69; P < .001). The mean score for the quality of the carotid patch increased significantly by 0.96 (27%) from fair (3.55 ± 0.87) to satisfactory (4.51 ± 0.76; P < .01). The median interassessor reliability for the quality of the carotid patch was acceptable (CA = 0.713) and for surgical skills was low (CA = 0.424). CONCLUSIONS: This study shows that lifelike simulation featuring pulsatile flow can increase surgical skills and technical quality in a highly sophisticated multistep vascular intervention. This training provides comparatively inexpensive and lifelike training possibilities for the adoption and assessment of surgical skills required to perform delicate vascular surgical procedures.

Calf muscle oxygen saturation and the effects of supervised exercise training for intermittent claudication.

OBJECTIVE: The mechanisms underlying the symptomatic improvement witnessed as a result of exercise training in intermittent claudication remain unclear. There is no reproducible evidence to support increased limb blood flow resulting from neovascularization. Changes in oxygenation of active muscles as a result of blood redistribution are hypothesized but unproven. This study sought evidence of improved gastrocnemius oxygenation resulting from exercise training. METHODS: The study recruited 42 individuals with claudication. After an initial control period of exercise advice, participants undertook a 3-month supervised exercise program. Spatially resolved near-infrared spectroscopy monitored calf muscle oxygen saturation (Sto(2)) during exercise and after a period of cuff-induced ischemia. Comparison was made with 14 individuals undergoing angioplasty for calf claudication. Clinical outcomes of claudication distance and maximum walking distance were measured by treadmill assessment. RESULTS: Significant increases occurred in mean [interquartile range] claudication disease (57 [38-78] to 119 [97-142] meters; P = .01) and maximum walking distance (124 [102-147] to 241 [193-265] meters; P = .02) after supervised exercise but not after the control period. No change occurred in resting Sto(2) at any interval. Angioplasty (27% [21-34] to 19% [13-29]; P = .02) but not exercise training (26% [21-32] vs 23% [20-31]; P > .20) resulted in a reduced Sto(2) desaturation in response to submaximal exercise and an increased hyperemic hemoglobin oxygen recovery rate after ischemia (0.48 [0.39-0.55] to 0.63 [0.52-0.69] s(-1); P = .01). However supervised exercise reduced the Sto(2) recovery half-time by 17% (82 [64-101] to 68 [55-89] seconds; P = .02). CONCLUSIONS: Supervised exercise training is not associated with increased gastrocnemius muscle oxygenation during exercise or increased hyperemic hemoglobin flow after a model of ischemia. This suggests that the symptomatic improvement witnessed is not the result of increased oxygen delivery to the active muscle. The enhanced recovery after exercise training therefore reflects a combination of enhanced metabolic economy and increased oxidative capacity, suggesting that exercise training helps reverse an acquired metabolic myopathy.

Local versus systemic mechanisms underlying supervised exercise training for intermittent claudication.

The mechanisms by which exercise training improves intermittent claudication remain unclear. In this article, the effects of local and systemic physiological factors on improved exercise tolerance after a supervised exercise program in claudicants are investigated. A total of 60 patients were randomized to 3 months of supervised exercise followed by 3 months of unsupervised exercise, or to exercise advice alone (control). Supervised exercise increased both pain-free and maximal walking distances. Heart rate during submaximal exercise and resting mean arterial pressure were lower after supervised exercise at 6 months. Serum lactate at maximum claudication increased significantly after 3 months in the supervised exercise group but this change had resolved by 6 months. Symptomatic improvement was accompanied by modest reductions in mean arterial pressure and submaximal heart rate on exercise. Increased serum lactate at maximum claudication subsequently declined despite continued improvement in walking distance, suggesting local adaptations to improve efficiency of muscle oxygen delivery and/or utilization.