Influence of popliteal vein thrombosis on subsequent ambulatory venous function measured by near-infrared spectroscopy

Noninvasive diagnosis and therapeutic effect evaluation of deep vein thrombosis in clinics by near-infrared spectroscopy

Deep vein thrombosis (DVT) has become a severe disease with a rising incidence rate. The conventional diagnosis relies on complicated imaging modalities that may also involve invasive contrast agent injection and ionizing procedures (e.g., venography). Noninvasive near-infrared spectroscopy (NIRS) methods have been explored which required the DVT patients to follow some exercise protocols. Here, we attempt to use portable NIRS under patients' natural state for DVT diagnosis. Nine DVT patients and seven healthy subjects participated in NIRS measurements of concentration of oxy- and deoxy-hemoglobins (Δ[HbO2] and Δ[Hb]) relative to data on a tissue mimicking phantom at six particular sites of calves. It was found that Δ[HbO2] is significantly lower in DVT patients than healthy ones, whereas Δ[Hb] is distinctly higher. Moreover, after thrombolytic therapy, both Δ[HbO2] and Δ[Hb] in DVT calves assume a gradual convergence to the curves of healthy ones. This reveals the potential of NIRS for the noninvasive, continuous, and straightforward monitoring/therapeutic effect evaluation of DVT in clinics with appropriate bedside monitoring capability.

Measurement of calf muscle oxygenation during light-intensity exercise in patients with post-thrombotic syndrome

BACKGROUND

Near-infrared spectroscopy (NIRS) provides continuous noninvasive monitoring of changes in the levels of oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) in tissues. The purpose of this study was to investigate changes in calf muscle O2Hb and HHb levels during standing and exercise in the follow-up of deep venous thrombosis (DVT).

METHODS

Forty-three patients with a first episode of unilateral proximal DVT were included. Final clinical manifestations were evaluated at a mean follow-up point of 53 months after diagnosis of DVT, and post-thrombotic syndrome (PTS) was considered to be present if the Villalta score was >5. Moreover, to assess the severity of PTS, the revised Venous Clinical Severity Score (VCSS) was employed. NIRS was used to measure changes in the levels of O2Hb and HHb in calf muscle. On standing, increases in O2Hb and HHb were calculated by subtracting the baseline value from the maximum value (ΔO2Hbst and ΔHHbst). The times taken for the O2Hb and HHb concentrations to become maximal (TO2Hbst, and THHbst) were also measured. During 10 tiptoe movements, the relative change in O2Hb was calculated by subtracting the value measured at the end of exercise from the value measured at the beginning of exercise (ΔO2Hbex). On the other hand, 10 tiptoe movements produced venous expulsion (ΔHHbEex) and a subsequent retention (ΔHHbRex). The oxygenation index (HbD; HbD = O2Hb - HHb) was also calculated at the end of standing and at the end of 10 tiptoe movements (ΔHbDst and ΔHbDex).

RESULTS

Among the 43 limbs evaluated, 21 had PTS. On standing, the ΔHbDst was significantly decreased in patients with PTS relative to the patients without PTS (12 ± 8, 22 ± 11 μmol/L; P = .001). The TO2Hbst was also significantly reduced in patients with PTS relative to those without (43 ± 41, 107 ± 58 seconds; P = .001). During 10 tiptoe movements, the ΔHHbEex was significantly reduced in patients with PTS relative to those without (-2 ± 1, -3 ± 3 μmol/L; P = .016). Similarly, the ΔHHbRex was significantly increased in patients with PTS relative to those without (8 ± 7, 3 ± 2 μmol/L; P = .001). Furthermore, falls in ΔHbDex were more pronounced in patients with PTS (-10 ± 16, 10 ± 10 μmol/L; P < .001). NIRS-derived TO2Hbst (r = -0.568; P < .001) and ΔHbDex (r = -0.645; P < .001) showed strong inverse correlations with VCSS. Similarly, NIRS-derived ΔHHbEex (r = 0.409; P < .01) and ΔHHbRex (r = 0.476; P < .01) showed moderate positive correlations and ΔHbDst (r = -0.422; P < .01) had a moderate inverse correlation with VCSS.

CONCLUSIONS

Changes in O2Hb and HHb concentrations differ between patients with and without PTS. The reduced TO2Hbst may indicate impairment of the venoarteriolar reflex in patients who have PTS. Furthermore, severe falls in HbD in patients with PTS might reflect the pain of venous claudication. These findings may have implications for investigations of the microcirculation in the context of post-thrombotic sequelae.

Measurements of calf muscle oxygenation during standing and exercise in patients with primary valvular insufficiency

OBJECTIVE

Despite the established role of the calf muscle pump for preventing chronic venous disorders, hemoglobin flow in the calf muscle is poorly understood. Near-infrared spectroscopy (NIRS) provides continuous noninvasive monitoring of changes in tissue-oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) levels. The purpose of this study was to investigate the changes in calf muscle O2Hb and HHb levels during standing and exercise in patients with primary valvular insufficiency (PVI).

METHODS

Eighty-three limbs in 81 patients with PVI were enrolled. The clinical manifestations of these patients were categorized according to the CEAP (Clinical, Etiologic, Anatomical, and Pathophysiologic) classification, and patients were divided into group I (C1-3S,Ep,As,d,p,Pr) and group II (C4-6S,Ep,As,d,p,Pr). Moreover, to assess the severity of PVI, the revised Venous Clinical Severity Score (VCSS) was employed. NIRS was used to measure changes in the calf muscle O2Hb and HHb levels. On standing, increases in O2Hb and HHb were calculated by subtracting the baseline value from the maximum value (ΔO2Hbst and ΔHHbst). The time elapsed until the maximum increases in O2Hb and HHb concentrations (TO2Hbst, and THHbst) were also measured. During 10 tiptoe movements, the relative change in O2Hb was calculated by subtracting the value measured at the end of exercise from the value measured at the beginning of exercise (ΔO2Hbex). On the other hand, 10 tiptoe movements produced venous expulsion (ΔHHbEex) and a subsequent retention (ΔHHbRex). The oxygenation index (HbD; HbD = O2Hb - HHb) was also calculated at the end of standing and 10 tiptoe movements (ΔHbDst and ΔHbDex).

RESULTS

Among the 83 limbs evaluated, 48 were classified as group I and 35 as group II. Standing caused increases in the levels of both ΔO2Hbst and ΔHHbst. However, there were no significant differences in these increases between the two groups. In contrast, the TO2Hbst was significantly reduced in group II in comparison with group I (55 ± 29 vs 36 ± 30 seconds; P = .007). During 10 tiptoe movements, a decrease in O2Hb concentration was observed, and there was no significant difference in ΔO2Hbex between group I and group II. In contrast, the ΔHHbRex was significantly increased in group II compared with group I (6 ± 7 vs 9 ± 6 μmol/L; P = .013). Furthermore, falls in ΔHbDex were more pronounced in group II (7 ± 16 vs -7 ± 16 μmol/L; P = .001). A statistically significant correlation was found between C of CEAP and the VCSS (r = 0.778; P < .001). Moreover, NIRS-derived TO2Hbst (r = -0.312; P < .01) and ΔHbDex (r = -0.332; P < .01) showed moderate inverse correlations with C of CEAP. Similarly, NIRS-derived ΔHbDex (r = -0.501; P < .001) had a strong inverse correlation, and ΔHbDst (r = -0.383; P < .001) and TO2Hbst (r = -0.378; P < .001) had moderate inverse correlations with VCSS.

CONCLUSIONS

Changes in O2Hb and HHb concentrations differ according to CEAP manifestation and VCSS. These data offer new insights into calf muscle hemodynamics at the microcirculation level in patients with PVI.

Changes in calf muscle deoxygenation after foam sclerotherapy in patients with superficial venous insufficiency

OBJECTIVE

This study assessed changes in the calf muscle deoxygenated hemoglobin (HHb) level during light-intensity exercise after ultrasound-guided foam sclerotherapy (UGFS) for superficial venous insufficiency.

METHODS

UGFS with 1% or 3% polidocanol foam (POL-F) was used to treat unilateral great saphenous vein reflux in 84 patients. Near-infrared spectroscopy (NIRS) was used to measure calf muscle HHb levels before and 3 months after UGFS. The calf venous HHb blood-filling index was calculated on standing, the calf venous HHb ejection index was obtained after one tiptoe movement, and the venous HHb retention index was obtained after 10 tiptoe movements. The primary end point was an evident improvement in calf muscle deoxygenation after UGFS. The secondary end point was obliteration of the great saphenous vein.

RESULTS

Treatment consisted of 1% POL-F in 48 limbs and 3% POL-F in the remaining 36. Ultrasound imaging at the 3-month follow-up demonstrated complete occlusion in 56.3% of the patients who received injections of 1% POL-F and in 66.7% of those who received injections of 3% POL-F. The difference in treatment outcome between the groups was not significant (P=.333). Reflux was absent in 39 limbs (81.3%) treated with 1% POL-F and in 34 limbs (94.4%) treated with 3% POL-F, and no significant difference was observed between the two groups (P=.076). Postsclerotherapy NIRS demonstrated significant reductions in the levels of the HHb filling index in both treatment groups (P=.039, P=.0001, respectively) and significant reductions in the levels of the HHb retention index (P<.0001, P=.008, respectively). However, the differences in the levels of the HHb ejection index before and after UGFS were not significant (P=.250, P=.084, respectively).

CONCLUSIONS

Our present findings suggest that changes in the values of these parameters may be of potential use for assessing the effects of foam sclerotherapy in patients with superficial venous insufficiency.

Prognostic impact of calf muscle near-infrared spectroscopy in patients with a first episode of deep vein thrombosis

BACKGROUND

The risk factors that affect the development of post-thrombotic syndrome (PTS) are not fully recognized, and it is difficult to reliably predict which patients are likely to develop PTS in acute phase of deep vein thrombosis (DVT).

AIMS

To investigate changes in calf muscle deoxygenated hemoglobin (HHb) levels after DVT, and to determine the indicative parameters reflecting the progression of PTS.

METHODS

Seventy-six consecutive patients with a first episode of unilateral DVT were prospectively enrolled. Clinical manifestations were categorized according to the CEAP (Clinical, Etiologic, Anatomical, and Pathophysiologic) classification, and the patients were divided into no-PTS (C(0-3)E(s),A(s,d,p),P(r,o)) and PTS (C(4-6)E(s),A(s,d,p),P(r,o)) groups. Near-infrared spectroscopy (NIRS) was used to measure calf muscle HHb levels at 6 months after diagnosis of DVT. The calf venous blood filling index (HHbFI) was calculated on standing, and the venous ejection index and the venous retention index (HHbRI) were then obtained after exercise. All patients were followed up for more than 24 months after the diagnosis of DVT.

RESULTS

Of 76 patients evaluated, 20 (26.3%) had PTS. The NIRS-derived HHbFI and HHbRI were significantly increased in patients who developed PTS in comparison with those who did not (P = 0.04 and P = 0.0001, respectively). HHbRI was significantly increased in patients with iliofemoral DVT in comparison with patients with calf DVT (P = 0.041). An optimal cut-off point of 2.9 for HHbRI showed the strongest ability to predict the development of PTS, with a sensitivity of 100% and a specificity of 82.1%.

CONCLUSIONS

HHbRI as measured by NIRS is significantly increased in patients with iliofemoral DVT as compared with those with calf DVT. Furthermore, HHbRI > 2.9 is a strong predictor of the development of PTS at 6 months.

The utility of quantitative calf muscle near-infrared spectroscopy in the follow-up of acute deep vein thrombosis

BACKGROUND

To investigate patterns of venous insufficiency and changes in calf muscle deoxygenated hemoglobin (HHb) levels after an acute deep vein thrombosis (DVT).

METHODS

A total of 78 limbs with an acute DVT involving 156 anatomic segments were evaluated with duplex scanning and near-infrared spectroscopy (NIRS) at 1, 3, 6 and 12 months. Venous segments were examined whether they were occluded, partially recanalized, and totally recanalized, and the development of venous reflux was noted. The NIRS was used to measure calf muscle HHb levels. Calf venous blood filling index (HHbFI) was calculated on standing, then the calf venous ejection index (HHbEI), and the venous retention index (HHbRI) were obtained after exercise.

RESULTS

The segments investigated were the common femoral vein (CFV; 38 segments), femoral vein (FV; 37), popliteal vein (POPV; 44), and calf veins (CV; 37). At 1 year, thrombi had fully resolved in 67% of the segments, 27% remained partially recanalized, 6% were occluded. The venous occlusion was predominant in the FV (24%) at 1 year. On the contrary, rapid recanalization was obtained in CV than proximal veins at each examination (P < 0.01). Venous reflux was predominant in POPV (55%), followed by FV (19%), and no reflux was found in CV. At 1 year, the HHbFI in POPV reflux patients was significantly higher than those with resolution (0.19 +/- 0.14, 0.11 +/- 0.05 microm s, P = 0.009, respectively). Similarly, there was a significant difference in the HHbRI between the two groups (3.08 +/- 1.91, 1.42 +/- 1.56, P = 0.002, respectively). In patients with FV occlusion, the value of HHbRI was significantly higher than those with complete resolution (2.59 +/- 1.50, 1.42 +/- 1.56, P = 0.011, respectively).

CONCLUSIONS

The lower extremity venous segments show different proportions of occlusion, partial recanalization, and total recanalization. The CV shows more rapid recanalization than proximal veins. The NIRS-derived HHbFI and HHbRI could be promising parameters as the overall venous function in the follow-up of acute DVT. These findings might be very helpful for physician in detecting patients who require much longer follow-up studies.

Use of near-infrared spectroscopic measurement at the buttocks during abdominal aortic surgery

During abdominal aortic surgery, dynamic changes occur in the pelvic circulation. Near-infrared spectroscopy (NIRS) was used in this study to evaluate arterial flow in the buttocks as a monitor of arterial flow in the pelvic area during abdominal aortic surgery. Twenty-two patients who underwent abdominal aortic aneurysmectomy comprised the study group. The NIRS probe was mounted on the left buttock during surgery, and the changes in oxy- and deoxy-hemoglobin (Hb) concentration were measured. In all cases Hb values reflected decreased arterial flow caused by aortic clamping and increased arterial flow after reconstruction of the distal arteries. The recovery pattern of the Hb values varied, but all recovered to the baseline value recorded before aortic clamping. None of the patients exhibited postoperative claudication of vessels supplying the gluteal muscles or colonic ischemia, and recovery time varied in accordance with the patient's arterial condition. This method is simple and enables individual evaluation of blood flow recovery from reconstructed arteries. This method allows approximate evaluation of the pelvic arterial flow of individual arteries, helps to predict postoperative claudication of the gluteal muscles, and offers additional information for evaluating colonic ischemia.