Low frequency oscillations assessed by diffuse speckle contrast analysis for foot angiosome concept

Abstract

An angiosome refers to a 3D tissue volume that is vascularized by a single artery and is a relatively new concept that is useful in vascular surgery; however, the direct relationship between arterial blood flow and micro-perfusion is still controversial. Here, we propose a diffuse speckle contrast analysis (DSCA), which is an emerging tissue perfusion monitoring modality, to investigate the correlations among low frequency oscillations (LFOs) measured from different areas on the feet of healthy subjects. We obtained reproducible results from the correlation analyses of LFOs, and their physiological implications were discussed. In order to confirm the changes in the frequency oscillations, we analyzed and compared the power spectral density changes due to heart rate variability in the electrocardiographic signal during reactive hyperemia and head-up tilt protocols.

Grades of Below-the-Ankle Arterial Occlusive Disease following the Angiosome Perfusion: A New Morphological Assessment and Correlations with the Inframalleolar GVG Stratification in CLTI Patients

“…Though doubts about the real clinical benefit of WDR for both bypass and EVT have been raised in contemporary literature 1-8, 10, 19-21, 32, 37 , using modern microcirculatory diagnostic methods with valuable topographic information 10,19,40,42 . While some authors have found the assessment of anatomical 6,10,16,28 and physiological 16,40,41 angiosomal flow by MRI oximetry 40 , trans-cutaneous laser Doppler 16,28 , or peripheral SPECT-Scan perfusion 10,[41][42][43] useful, others have questioned the utility of topographic reperfusion using white-light tissue spectrophotometry 44 , and low-frequency oscillations analyzed by diffuse speckle contrast analysis 45 . The clinical value of all these studies that support or refute specific postoperative angiosomal microcirculatory changes is indisputable.…”

“…The graded anatomical scale presented in this study represents an initial observation that needs larger clinical validation. However, our study reveals that not all reported postoperative microcirculatory patterns and measurements 40-45, 47, 51 are performed in equivalent anatomical degrees of CLTI disease 10,43 , and in the corresponding pre-or postreperfusion physiological phases 10,[45][46][47][48][49][50][51] . It also suggests that probably not all previously published studies compare limbs that share similar anatomical and functional collateral indexes, densities of ramifications, and calibers of communicants, and thus do not have equivalent peripheral arterial resistances 8,16,53 that follow distinct territories of angiosomal reperfusion 10,17,49 .…”

“…Therefore, it appears that a "correct" postoperative angiographic foot flow cannot always be equivalent to appropriate regional tissue oxygenation, particularly in severe neuropathic diabetic limbs (that may exhibit a cutaneous "steal" phenomenon) 15,16,52 . Postoperative TAAP flow needs to be further studied in sequential phases of tissue reperfusion [43][44][45][46][47]52 . When comparing EVT to bypass 1,5,8,33 or solely for bypass performed with angiosomal direct vs. indirect revascularization 5,33,[54][55][56] , results will probably show different outcomes since addressing dissimilar complexity of the diseased TAAP, foot arches, and related collaterals like in our grades A and B vs. that in grades C and D comparison.…”

Experimental characterization of diffuse speckle pulsatile flowmetry system

“…More details of DSPF and DSCA can be found in [8] and [12] respectively, and in Supplementary Table 1 Both these modalities are increasingly being employed in research studies for biomedical and clinical applications. Since it was developed in 2013, DSCA has been used in studies to assess tissue perfusion for the foot angiosome concept [13] and cerebral blood flow monitoring during middle cerebral artery occlusion (MCAO) in a rodent model [14]. In the former, it was able to measure the low frequency oscillations of blood flow in the foot, showing promising potential to support the diagnosis and monitoring of foot ulcers which is a complication arising from diabetes [13].…”

“…Since it was developed in 2013, DSCA has been used in studies to assess tissue perfusion for the foot angiosome concept [13] and cerebral blood flow monitoring during middle cerebral artery occlusion (MCAO) in a rodent model [14]. In the former, it was able to measure the low frequency oscillations of blood flow in the foot, showing promising potential to support the diagnosis and monitoring of foot ulcers which is a complication arising from diabetes [13]. In the latter, it was able to detect the decrease in perfusion in neurological tissue as a result of MCAO, showing potential to observe cerebral hemodynamics associated with transient ischemic stroke [14].…”