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.