Comparative Study of NonInvasive Vascular Imaging Techniques in the Evaluation of Chronic Venous Leg Ulcers

Abstract

Aim: To compare noninvasive vascular imaging techniques in the evaluation of chronic venous leg ulcers, and to detect the discriminating parameters between primary valvular incompetence (PVI) and postthrombotic syndrome (PTS).Methods: A total of 61 limbs with chronic venous ulcers were included in this study. Of 61 limbs, 31 had PVI and remaining 30 had documented PTS. The distribution of venous reflux including superficial, deep, and perforating vein was determined by duplex ultrasound. The venous functions including venous volume (VV: ml), venous filling index (VFI: ml/sec), ejection fraction (EF: %), and residual volume fraction (RVF: %) were evaluated by air plethysmography (APG). The near–infrared spectroscopy (NIRS) was used to measure calf muscle total hemoglobin (tHb), oxygenated hemoglobin (O2Hb), and deoxygenated hemoglobin (HHb) levels using APG exercise protocol, and the changes in these parameters were divided into three patterns; Type I: The HHb does not increase beyond the O2Hb during the total procedure. Type II: The HHb increases beyond the O2Hb during the excise. Type III: The HHb increases beyond the O2Hb during the total procedure. Patients with Type III were considered to have most significant calf muscle dysfunction.Results: Superficial venous incompetence was significantly predominant in the PVI (p = 0.031). The proportion of deep vein incompetence was significantly higher in the PTS (p = 0.023). Of these, patients with PTS had significantly higher proportion of femoral vein (FV) and popliteal vein (POPV) incompetence compared to these with PVI (p = 0.0006, 0.0015, respectively). There was no statistically significant difference in the proportion of perforator incompetence between the groups (p = 0.611). There were no significant differences in VV (94.8 ± 43.7, 84.7 ± 48.8, p > 0.999), VFI (5.04 ± 2.49, 5.19 ± 3.15, p = 0.236), EF (51.9 ± 19.2, 47.2 ± 25.3, p = 0.903), and RVF (54.8 ± 22.3, 66.1 ± 29.8, p = 0.378). In the NIRS examinations, Type I was found in 20 limbs (64.5%) in the PVI and 3 (10%) in the PTS, and this was a statistically significant (p < 0.0001). On the contrary, Type III was seen in 1 limb (3.2%) in the PVI and 19 (63.3%) in the PTS. The proportion of Type III was significantly higher in the PTS (p < 0.0001).Conclusions: These data suggest that reflux in the FV and POPV might play more important role in the development of venous leg ulcers in patients with PTS. The APG–derived parameters did not improve the discrimination power between the two groups. The increased NIRS–derived HHb in the exercising calf muscle is profound in patients with PTS, suggestive of a promising parameter both in the discrimination of the patients with chronic venous leg ulcers and in the follow–up of the patients with deep vein thrombosis.