Venous compliance and clinical implications

Abstract

Compliance is a characteristic of every deformable system. Compliance is very clear concept in physics and mechanics but in clinics, perhaps, is not the same. However, in veins compliance fits perfectly with the function of drainage of the venous system. Volumetric increase (dV) of the content is correlated with pressure increase (dP) inside the vein according to the equation C’= dV/dP. In humans 75% of the blood is located in the venous system, primarily because the molecular components of a vein media layer is significantly more compliant to that of arteries. This property is fundamental to understanding the change in blood volume in response to a change in posture. Measurements of venous compliance in clinical practice can be done by the means of ultrasound, as well as with the plethysmography. Ultrasound methods assimilate the cross sectional area to the volume of the vein, because it reflects the blood content. Changes in cross sectional area can be reliably measured in response to a change in posture, while pressure can be derived from the hydrostatic pressure changes. Venous compliance is of paramount importance also in pulsatile veins such as the inferior or superior vena cava and the jugular veins, where high resolution ultrasound may accurately derive the cross sectional area. Clinical implications of the mechanical properties of the venous wall are extensively discussed, including the need of dedicated venous stenting, which takes into account venous compliance as the main parameter of the venous function. In addition, venous compliance is the interpretative key for a better understanding of plethysmography curves, as well as of varicose veins and of their return to normal cross sectional area following ambulatory venous pressure reduction.

A novel endovenous scaffold for the treatment of chronic venous obstruction in a porcine model: Histological and ultrastructural assessment

“…For instance, in the human internal jugular vein, the CSA ranges between 17 AE 8 mm 2 in upright and 106 AE 37 mm 2 in supine position; similar ranges are covered by the iliac veins and/or by the major deep veins of the lower limbs at postural changes. 16 Differently from the current venous stent, Petalo CVS design has been developed to be more compliant to the change in CSA of the venous system. In addition, the novel configuration of the scaffold induces a biological response of the vein wall only in a limited area of contact.…”

“…Venous compliance is an inherent mechanical property of the vein which of course is not contemplated by the current devices. [16][17][18] Quite recently, a compliant nitinol vein scaffold denominated "Petalo CVS," demonstrated intriguing profiles of both safety and efficacy in a porcine model, but histological information about the interaction of the novel stent with the venous wall were completely lacking. 19 Therefore, the purpose of the present pilot study was to evaluate the histologic and ultrastructural aspects of the jugular veins in response to "Petalo CVS" implant in a porcine model.…”

How to Assess Illusory May–Thurner Syndrome by Ultrasound

“…In similar cases we increase the gravitational overload slightly and repeat the investigation with the patient in a semi-settled 45 position. 2 The presence of illusory MTS is followed by relief of the compression and flow recovery in the LIV (Fig. 1, right).…”

The omohyoid and sternocleidomastoid muscles entrapment of the internal jugular vein: Which role in Mèniére disease patients? Treatment perspective description

“…Zamboni and his team have first investigated the role of venous system in the cerebral hemodynamic mechanisms as well as brain and ear physiology, describing its characteristics through the anatomical and functional point of view, indicating the differences in terms of elasticity and compliance 1 and underlining the comparable importance in relation to the arterial system that, until then, had attracted almost completely the attentions and finally defining the chronic cerebro-spinal venous insufficiency (CCSVI) as an altered head outflow due to intraluminal defects 2 and generating an increased interest in the last years about the possible involvement as common ethiopategenetic mechanism in different pathologies as multiple sclerosis (MS), Parkinson or Alzheimer disease, Mèniére syndrome (MèS) and migraine. 3 Afterward the progress made in the evaluation of possible anomalies able to effect an altered cerebral outflow, allowed to understand how, in addition to the detection of vascular defects described as Truncular venous malformations (TVMs) and expressed as the result of vascular trunk developmental defects occurring during the embryogenesis later stage, the point of view has progressively widened, evaluating the possible role of the presence of a muscular external compression.…”