Venous hemodynamic changes in lower limb venous disease: the UIP consensus according to scientific evidence.

There are excellent guidelines for clinicians to manage venous diseases but few reviews to assess their hemodynamic background. Hemodynamic concepts that evolved in the past have largely remained unchallenged in recent decades, perhaps due to their often complicated nature and in part due to emergence of new diagnostic techniques. Duplex ultrasound scanning and other imaging techniques which evolved in the latter part of the 20th century have dominated investigation. They have greatly improved our understanding of the anatomical patterns of venous reflux and obstruction. However, they do not provide the physiological basis for understanding the hemodynamics of flow, pressure, compliance and resistance. Hemodynamic investigations appear to provide a better correlation with post-treatment clinical outcome and quality of life than ultrasound findings. There is a far better prospect for understanding the complete picture of the patient's disability and response to management by combining ultrasound with hemodynamic studies. Accordingly, at the instigation of Dr Angelo Scuderi, the Union Internationale de Phlebologie (UIP) executive board commissioned a large number of experts to assess all aspects of management for venous disease by evidence-based principles. These included experts from various member societies including the European Venous Forum (EVF), American Venous Forum (AVF), American College of Phlebology (ACP) and Cardiovascular Disease Educational and Research Trust (CDERT). Their aim was to confirm or dispel long-held hemodynamic principles and to provide a comprehensive review of venous hemodynamic concepts underlying the pathophysiology of lower limb venous disorders, their usefulness for investigating patients and the relevant hemodynamic changes associated with various forms of treatment. Chapter 1 is devoted to basic hemodynamic concepts and normal venous physiology. Chapter 2 presents the mechanism and magnitude of hemodynamic changes in acute deep vein thrombosis indicating their pathophysiological and clinical significance. Chapter 3 describes the hemodynamic changes that occur in different classes of chronic venous disease and their relation to the anatomic extent of disease in the macrocirculation and microcirculation. The next four chapters (Chapters 4-7) describe the hemodynamic changes resulting from treatmen by compression using different materials, intermittent compression devices, pharmacological agents and finally surgical or endovenous ablation. Chapter 8 discusses the unique hemodynamic features associated with alternative treatment techniques used by the CHIVA and ASVAL. Chapter 9 describes the hemodynamic effects following treatment to relieve pelvic reflux and obstruction. Finally, Chapter 10 demonstrates that contrary to general belief there is a moderate to good correlation between certain hemodynamic measurements and clinical severity of chronic venous disease. The authors believe that this document will be a timely asset to both clinicians and researchers alike. It is directed towards surgeons and physicians who are anxious to incorporate the conclusions of research into their daily practice. It is also directed to postgraduate trainees, vascular technologists and bioengineers, particularly to help them understand the hemodynamic background to pathophysiology, investigations and treatment of patients with venous disorders. Hopefully it will be a platform for those who would like to embark on new research in the field of venous disease.

Effect of elastic compression stockings on venous hemodynamics during walking.

PURPOSE: Venous hemodynamics evaluated during walking better reflect changes that occur under active physiologic conditions than do conventional static modes of exercise such as tip-toe exercise, knee bending, or dorsiflexion. We prospectively studied the efficacy of air-plethysmography (APG) in monitoring venous hemodynamics during ambulation, and with this method we determined the hemodynamic effects of graduated elastic compression stockings on the lower limb during walking at various speeds. METHODS: The residual volume fraction (RVF%) during treadmill walking was monitored with APG in 10 limbs with primary chronic venous insufficiency (CVI)(CEAP(2-4)) at four speeds (1.0, 1.5, 2.0 and 2.5 km/h consecutively), with and without elastic compression (21 mm Hg at the ankle). The method was validated in comparison with standard APG, which is based on tip-toe exercise. RVF obtained during treadmill walking at 1.5 km/h was correlated with RVF measured with standard APG in 30 subjects: 12 healthy volunteers, 11 patients with primary CVI, and 7 postthrombotic limbs. Data were analyzed with nonparametric statistics. RESULTS: RVF measurements during walking were reproduced with an intra-day coefficient of variation of 5.1% to 16.5%. RVF during walking correlated well with RVF during standard APG (tip-toe) (r = 0.5, P =.004). At each of the investigated walking speeds, stockings improved venous hemodynamics by decreasing RVF, from a median of 50.5% without stockings to 40.5% with stockings at 1.0 km/h (19.8% decrease), from 49% to 39.5% at 1.5 km/h (19.4% decrease), from 50.5% to 41% at 2.0 km/h (18.8% decrease), and from 53% to 45.5% at 2.5 km/h (14.2% decrease) (all speeds, P <.02). Efficacy of the stockings in decreasing RVF (percent change in RVF) was similar across the spectrum of examined speeds (P =.47). During walking with elastic stockings, nominal RVF values were also similar across the spectrum of walking speeds, except at 2.5 km/h (P =.012). During walking without stockings, RVF did not change with treadmill speed, nor did it differ from that obtained with conventional APG (tip-toe) (P =.46). The percentage decrease in RVF generated with elastic stockings correlated with the venous filling index (r = 0.73, P =.017) at 1.0 km/h. CONCLUSIONS: APG is a reproducible and valid method for monitoring venous hemodynamics during walking. Graduated elastic compression stockings significantly improved venous hemodynamics by reducing RVF in limbs with primary CVI at all examined walking speeds (1.0 to 2.5 km/h). The effect was linearly correlated with the amount of reflux (1.0 km/h). The modified application of APG during walking offers a new noninvasive method for assessment of venous hemodynamics in limbs with CVI, enabling quantification of the actual effect of elastic compression therapy during ambulation.