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Prolonged sitting, which is known to impair peripheral vascular function, often occurs in spaces (e.g., offices) with mild hypercapnic atmospheres. However, the effects of prolonged sitting in hypercapnic conditions on vascular function are unknown. Therefore, the purpose of this study was to investigate the effects of prolonged sitting in mild hypercapnic conditions on vascular and autonomic function in humans. Twelve healthy young adults participated in two experimental visits that consisted of sitting for 2.5 h in a control condition [normal atmospheric conditions sitting (PSIT)] or a mild hypercapnic condition (HCAP; CO 2  = 1,500 ppm). During each visit, heart rate variability (HRV), blood pressure (BP), pulse wave velocity (PWV), augmentation index (AIx), brachial and popliteal artery flow-mediated dilation (FMD), and near-infrared spectroscopy (NIRS) were assessed before and after prolonged sitting. Sitting significantly decreased AIx in both groups ( P < 0.05). Brachial and popliteal FMD were reduced with sitting ( P < 0.05), and the reduction in popliteal FMD was amplified by HCAP ( P < 0.05). Baseline microvascular oxygenation was decreased following sitting in both groups ( P < 0.05). However, microvascular reoxygenation upon cuff release was slower only in HCAP ( P < 0.05). HRV, HR, BP, and PWV did not significantly change with sitting in either group ( P > 0.05). We conclude that prolonged sitting attenuated both brachial and popliteal endothelial function and was associated with perturbed microcirculation. Additionally, mild hypercapnic conditions further impaired peripheral endothelial and microvascular function. Together, these findings suggest that prolonged sitting is accompanied by a host of deleterious effects on the vasculature, which are exacerbated by mild hypercapnia. NEW & NOTEWORTHY The results of this study reveal that prolonged sitting attenuates endothelial function and microvascular function. Additionally, prolonged sitting with mild hypercapnia, which is similar to everyday environments, further exacerbates peripheral endothelial function and microvascular function.

This study hypothesized that central and local reflex mechanisms affecting vascular conductance (VC) through the popliteal artery compensated for the reduction in muscle perfusion pressure (MPP) to maintain popliteal blood flow (PBF) during head-down tilt (35˚ HDT), but not in head-up tilt (45˚ HUT). Resting measurements were made on 15 healthy men in prone position to facilitate the access to the popliteal artery, on two separate days in random order during horizontal (HOR), HDT or HUT. In each body position, the body was supported, and the ankles were maintained in relaxed state so that there was no muscle tension, as with normal standing. Popliteal blood flow velocity and popliteal arterial diameter were measured by ultrasound, and PBF was calculated. MPP was corrected to mid-calf from measured finger cuff pressure, and VC was estimated by dividing PBF by MPP. The MPP in HDT (48 ± 2 mmHg) was ~100mmHg less than in HUT (145 ± 2 mmHg). PBF was similar between HOR (51 ± 18 ml( ) min(-1) ) and HDT (47 ± 13 ml min(-1) ), but was lower in HUT (30 ± 9 ml min(-1) ). VC was different between HDT (1·0 ± 0·3 ml min(-1)  mmHg(-1) ), HOR (0·6 ± 0·2 ml min(-1)  mmHg(-1) ) and HUT (0·2 ± 0·1 ml min(-1)  mmHg(-1) ). In conclusion, the interactions of central and local regulatory mechanisms resulted in a disproportionate reduction of VC during HUT lowering PBF even though MPP was higher, while in HDT, increased VC contributed to maintain PBF at the same level as the HOR control condition., (© 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.)

In addition to standard risks associated with all orthopedic surgical procedures, posterior cruciate ligament (PCL) reconstruction poses some relatively unique potential complications. These complications arise from a combination of several factors: the relative infrequency of PCL injuries, the lack of knowledge and experience in treating them, the proximity of neurovascular structures to the PCL, and the technically demanding nature of reconstructive procedures. This article discusses the anatomy, pathogenesis, and prevention of intraoperative and postoperative complications of PCL surgery including neurovascular injury, osteonecrosis, fracture, motion loss, and persistent laxity.

Additional therapy of symptomatic popliteal artery aneurysm includes intraoperative lysis for the treatment of the descending thrombosis and spinal cord stimulation for cases of chronic deterioration of the peripheral perfusion state. Between 1989 and 1996, we treated 50 patients with 55 symptomatic aneurysms using this concept, 18 of them as emergency cases. We reached a postoperative amputation rate of 12.7% and good long-term functional results in 34 of 37 patients.

We report the case of a patient with saphenous neuralgia secondary to iatrogenic trauma resulting from bypass surgery in the femoral-popliteal region. Early symptoms of this condition were medial calf and ankle pain, with no findings of motor and reflex abnormalities. Exploration of the thigh 2 years later revealed a neuroma of the nerve in the distal dissection site, medial to the knee. Resection of the neuroma alleviated this condition. It is noted that saphenous neuropathy is seen as a spontaneous entrapment syndrome as well as a complication of orthopedic and vascular procedures performed on the medial area of the knee. Saphenous neuralgia is often not recognized by neurosurgeons. If the condition is intractable, it does respond to surgical therapy.

Lumbar sympathectomy in majority of patients with thromboangiitis was found to be followed by a reduced pathogenetically reliable orthostatic and post-orthostatic++ spasm of the diseased arteries. Patients with persistent and continuous remission had normo- and hypotonic orthostatic reaction of the extremity vessels. Remote clinical results of the intervention on lumbar sympathetic ganglia were dependent on the degree of correction of local angiotonic and angiospastic disorders.

Lumbar sympathectomy still has an important role in the surgical treatment of occlusive peripheral arterial diseases of the lower limbs located below the inguinal ligament, when the presence of peripheral lesions makes revascularization difficult. A consecutive series of 143 patients who underwent lumbar sympathectomy was considered, and the clinical, angiographic and haemodynamic findings evaluated. Haemodynamic studies on these patients showed a relation between the clinical improvement and the pressure index, measured at the ankle before lumbar sympathectomy. The patients with pressure index values above 0.5 had a symptomatic improvement whereas the patients with a pressure index below 0.3 gave less good results. It is therefore believed that lumbar sympathectomy showed not be considered a second operative choice but an elective operation, especially in patients affected by lesion of the superficial femoral artery, the popliteal artery and its branches, with pressure indices above 0.5 where revascularization is not possible.

The structural and functional heterogeneity in rat mesenteric and hind leg arteries has been established. The results of histochemical, biochemical and physiological studies showed the change of adrenergic plexus density, content and ratio of catecholamines and contractility of smooth muscle cells along the superior mesenteric artery. The proximal part of the artery is sparsely innervated and contains only traces of noradrenaline. It demonstrates small contractile response to nerve stimulation, noradrenaline and potassium chloride. Increased nerve density, noradrenaline content and responsiveness has been revealed in the distal part of the artery. The same correlation between the nerve density and vessel reactivity was obtained in hind leg arteries: the more innervated popliteal artery demonstrates more strong contractile response than the femoral artery. It has been also revealed the organ heterogeneity. In general, hind leg arteries are best innervated, contain more catecholamines and demonstrate increased maximal contractility in comparison to mesenteric arteries. The femoral and popliteal arteries have not phasic contractile activity which is very well expressed in the mesenteric ones.