Stefano Ricci
AbstractReflux duration longer than 0.5 s is the cut-off point for the diagnosis of valvular incompetence. It is induced by a calf compression/release maneuvre (CCRM) in a weight-loaded position, with a full venous reservoir. CCRM is a pre-valve challenge test; reflux stops when the reservoir is full. In contrast, a Valsalva maneuvre (VM) is a post-valve challenge test and also a validated technique to induce reflux. It is performed in a supine position, when the venous reservoir is only partially filled. The Authors measured the volume of blood displaced during a standardized VM within an incompetent GSV (18 patients C2, reflux until the popliteal crease). A standard VM was performed by taking a deep breath during 3 s, a strain during the next 3 s, and then a relaxation during the final 3 s. GSV diameters during stain and relaxation were measured just distal to the SFJ. Volume flow in cc/min (time average mean velocity x diameter) multiplied by 3/60 gave volume displacement in 3 s. A median of 25 mL blood was displaced into the GSV over 3 s during straining with only 9 mL blood out of the GSV during the following 3 s of relaxation. As far as the volume is concerned, the different physical properties of foam must be referred to and the displaced foam volumes are likely to be lower. During ultrasound guided foam sclerotherapy (UGFS), VM is unavoidable (leg movements, cough, head lifting, strains, stocking application) and bolus displacement of foam into deep veins, and blood/foam mixing may cause concern over safety and efficacy. Protocols should be formulated to minimize the VM risks (stocking application, avoid standing, talking and coughing soon after the injection). Putting on a below-the-knee stocking before the procedure may be of benefit. This study has also shown that reflux duration following a VM can be determined by the physician and not by the pathology of the disease. |
At the end of the UGFS procedure, the GSV is submitted to a spasm of unknown but relatively long duration as a direct effect of the foam on the muscular layer of the vein. When this occurs, the volume of the affected GSV is markedly reduced. Therefore, when the patient gets up and begins to walk, the VM is likely to displace a substantially reduced volume. For this reason, this interesting study cannot apply directly to the UGFS procedure. However, a VM might affect subsequent recanalization. If this is true, the VM should also be studied in the standing position, because this is more representative of the venous circulation in everyday life. The benefit of the stockings, possibly analyzed during VM, is cited in the abstract but unfortunately is not described in the paper; this is a pity. Finally, the 4 patients with GSV reflux at a standing compression/relaxation maneuvre but with negative VM in a supine position probably had a competent terminal valve, as this is commonly found in approximately 30% of cases of GSV incompetence.
Foam sclerotherapy causes substantial venospasm of the GSV and Ricci correctly concludes that foam displacement, back and forth across the SFJ during a VM, may be minimal or even non-existent. The reported results apply to blood, not foam. The hemodynamic properties of foam in vivo after sclerotherapy are not known and this needs to be the subject of future research. A VM is likely to be more detrimental during the injection than after the onset of venospasm. The purpose of a partially-applied graduated compression stocking, up to the level of the sclerotherapy injection site, was to avoid any strain the patient may exert in providing a counterforce during the initial application of the stocking by the physician. We did not evaluate a VM with a stocking in place. This may have reduced the volume displaced through a reduction in the GSV calibre and the venous reservoir. Instead, we assessed peak velocity and volume flow across the SFJ during the application of a compression stocking.1 Lattimer et al. discussed foam-induced venospasm. We agree that a competent terminal valve is the likely explanation for the absence of GSV reflux during a VM in the presence of significant reflux after manual CCRM. This discrimination is an essential step in the evaluation of patient profile prior to saphenous conservation surgery.
1. Lattimer CR, Azzam M, Kalodiki E, Geroulakos G. Hemodynamic changes at the saphenofemoral junction during the application of a below-knee graduated compression stocking. Dermatologic Surgery 2012. [In press]
[TOP]