Micro-lightguide spectrophotometry for tissue perfusion in ischemic limbs

Abstract

To validate micro-lightguide spectrophotometry (O2C) in patients with lower limb ischemia and to compare results with those obtained from toe blood pressure. Methods: We prospectively examined 59 patients, 24 of whom complained of claudication, 31 had critical ischemia, and four were asymptomatic. Diabetes was present in 19 (32%) patients. Saturation (SO 2) and flow measured with O2C were determined with the limb in the horizontal position followed by a 55-cm elevation. Toe pressures were determined in the horizontal position only. In addition, 13 patients were examined before and, on average, 3 days after revascularization. Results: Median SO 2 was 62% (25%-75% percentile: 37%-75%) with the limb in the horizontal position and 16% (3%-41%) with the limb elevated. Comparing the individual toe pressures with SO 2 values measured in the horizontal position and elevated position revealed a significant correlation (r s ‫؍‬ 0.40; P < .01 and r s ‫؍‬ 0.56; P < .01, respectively). A low SO 2 (ie, <40% in the horizontal position and <20% in the elevated position) was highly predictive of a toe pressure of 40 mm Hg or less. In the horizontal position, the positive predictive value was 100%, whereas the negative predictive value was 47%. The similar figures in the elevated position were a positive predictive value of 97% and a negative predictive value of 68%. Postoperatively, SO 2 increased significantly from 27% (P25%-75%: 11%-75%) to 79% (68%-87%) in the horizontal position (P ‫؍‬ .008) and from 14% (P25%-75%: 2%-39%) to 55% (30%-73%) in the elevated position (P ‫؍‬ .011), respectively. Looking at the individual 13 cases in which revascularization was performed, three patients had a partial reconstruction (ie, superficial femoral artery occlusion distal to a central reconstruction or reconstruction to a popliteal blind segment). These patients had significantly lower postoperative SO 2 as well as toe pressure compared with the 10 patients with unobstructed flow to the foot. Conclusions: O2C was easy to use, fast, and painless. The most useful finding was the high predictive value of a low saturation and the rise in O2C values after successful revascularization.

Immediate changes of angiosome perfusion during tibial angioplasty

“…Similar probes have proven feasible for CLI patients in previous studies. 2,26 Statistical analysis. SPSS 21 (IBM Corp, Armonk, NY) was used for the statistical analysis.…”

Micro-Lightguide Spectrophotometry (O2C) for Lower Limb Perfusion: Effects of Exercise Walking in Claudicants

“…However, due to the variability it is best suited for the study of phenomena resulting in major changes eliminating some inherent variability. 7 Further studies with measurements being taken on moving object have yet to be explored.…”

“…Standardizing the exertion with a treadmill test enables us to examine the decline and the subsequent recovery of microcirculatory measures. 7 In addition, the same set-up may be used for the study of various modalities in the research of microcirculatory changes following a more or less standardized physiologic stimulus. In a previous study, we found the predictive value of O2C good in cases of low saturation, but in general, insufficient when differentiating normal perfusion from PAD when investigated at rest, which is not surprising as patients suffering from claudication experience no symptoms at rest.…”

“…A study of the technique in a clinical setting has proven it easy to use and with a fair predictive value of a low saturation. 7 The aim of this study is to investigate, by means of O2C, the microcirculation in patients with IC before and after a treadmill test, and before and after 12 weeks of exercise walking. We hypothesized that a possible ischemia at skin level induced by exercise could be detected with O2C.…”

A systematic review of diagnostic techniques to determine tissue perfusion in patients with peripheral arterial disease

“…One prospective cohort study was found in the literature search [56]. Details are provided in Table 1.…”