Color Doppler and Microvascular Flow Imaging to Evaluate the Degree of Inflammation in a Case of Hidradenitis Suppurativa

Microvascular Flow Imaging is a new ultrasound technique with better ability than Color Doppler Imaging to identify small vessels that have slow blood flow, and it permits better evaluation of the features, especially microvascular architecture, of various lesions. We describe a case of inguinal hidradenitis suppurativa in a patient with positive risk factors (young age, female, smoker, and obese), diagnosed by ultrasonography using B-Mode, Color Doppler, and finally also with Microvascular Flow Imaging. Our aim is to demonstrate the usefulness of this new technique in characterization of lesions.

Microvascular Flow Imaging in a case of Portal Vein Thrombosis

Portal vein thrombosis (PVT) is a common complication of liver cirrhosis and is often the first sign of undetected hepatocellular carcinoma. It is crucial to differentiate malignant from benign thrombosis in determining prognosis and treatment. We describe a case of malignant PVT, detected for the first time by a new ultrasound technology, microvascular flow imaging, which can depict low flow in small vessels.

Inhaled Nitric Oxide with Intravenous Hydrocortisone Does Not Improve Microvascular Perfusion in Septic Pigs.

BackgroundCapillary flow restoration in sepsis may prevent organ dysfunction caused by a prolonged impairment of microvascular flow. The main aim of the study was to investigate the microcirculatory effect of inhaled nitric oxide (iNO) combined with intravenous hydrocortisone in a porcine model of sepsis. The second aim was to evaluate the influence of hemodynamic resuscitation with noradrenaline and crystalloids on capillary flow.Materials and MethodsIn the study, 11 piglets of Polish breed were generally anaesthetized and underwent surgical colon perforation. The animals were randomly allocated to one of three treatment groups. Group 1 received iNO and hydrocortisone, whereas Group 2 was a control group. Both groups were resuscitated with crystalloids and noradrenaline if hypotensive. Group 3 received no treatment at all.In a 30-hour period of observation, we assessed microcirculation using sidestream dark field imaging (SDF) and monitored hemodynamics with a pulmonary artery catheter.Results We found no effect of iNO with hydrocortisone on microcirculation in septic piglets. Fluid and vasopressor treatment postponed microvascular flow impairment and led to a higher microcirculatory flow index, greater proportion of perfused vessels, and perfused vessel density.ConclusionCrystalloid and vasopressor treatment postpones microvascular flow derangement and organ dysfunction in septic piglets.

Comparison of renal histopathology and gene expression profiles between severe COVID-19 and bacterial sepsis in critically ill patients

Background The mechanisms driving acute kidney injury (AKI) in critically ill COVID-19 patients are unclear. We collected kidney biopsies from COVID-19 AKI patients within 30 min after death in order to examine the histopathology and perform mRNA expression analysis of genes associated with renal injury. Methods This study involved histopathology and mRNA analyses of postmortem kidney biopsies collected from patients with COVID-19 (n = 6) and bacterial sepsis (n = 27). Normal control renal tissue was obtained from patients undergoing total nephrectomy (n = 12). The mean length of ICU admission-to-biopsy was 30 days for COVID-19 and 3–4 days for bacterial sepsis patients. Results We did not detect SARS-CoV-2 RNA in kidney biopsies from COVID-19-AKI patients yet lung tissue from the same patients was PCR positive. Extensive acute tubular necrosis (ATN) and peritubular thrombi were distinct histopathology features of COVID-19-AKI compared to bacterial sepsis-AKI. ACE2 mRNA levels in both COVID-19 (fold change 0.42, p = 0.0002) and bacterial sepsis patients (fold change 0.24, p < 0.0001) were low compared to control. The mRNA levels of injury markers NGAL and KIM-1 were unaltered compared to control tissue but increased in sepsis-AKI patients. Markers for inflammation and endothelial activation were unaltered in COVID-19 suggesting a lack of renal inflammation. Renal mRNA levels of endothelial integrity markers CD31, PV-1 and VE-Cadherin did not differ from control individuals yet were increased in bacterial sepsis patients (CD31 fold change 2.3, p = 0.0006, PV-1 fold change 1.5, p = 0.008). Angiopoietin-1 mRNA levels were downregulated in renal tissue from both COVID-19 (fold change 0.27, p < 0.0001) and bacterial sepsis patients (fold change 0.67, p < 0.0001) compared to controls. Moreover, low Tie2 mRNA expression (fold change 0.33, p = 0.037) and a disturbed VEGFR2/VEGFR3 ratio (fold change 0.09, p < 0.0001) suggest decreased microvascular flow in COVID-19. Conclusions In a small cohort of postmortem kidney biopsies from COVID-19 patients, we observed distinct histopathological and gene expression profiles between COVID-19-AKI and bacterial sepsis-AKI. COVID-19 was associated with more severe ATN and microvascular thrombosis coupled with decreased microvascular flow, yet minimal inflammation. Further studies are required to determine whether these observations are a result of true pathophysiological differences or related to the timing of biopsy after disease onset.

Impaired cerebral microcirculation in isolated REM sleep behaviour disorder

During the prodromal period of Parkinson’s disease and other α-synucleinopathy-related parkinsonisms, neurodegeneration is thought to progressively affect deep brain nuclei, such as the locus coeruleus, caudal raphe nucleus, substantia nigra, and the forebrain nucleus basalis of Meynert. Besides their involvement in the regulation of mood, sleep, behaviour, and memory functions, these nuclei also innervate parenchymal arterioles and capillaries throughout the cortex, possibly to ensure that oxygen supplies are adjusted according to the needs of neural activity. The aim of this study was to examine whether patients with isolated REM sleep behaviour disorder, a parasomnia considered to be a prodromal phenotype of α-synucleinopathies, reveal microvascular flow disturbances consistent with disrupted central blood flow control. We applied dynamic susceptibility contrast MRI to characterize the microscopic distribution of cerebral blood flow in the cortex of 20 polysomnographic-confirmed patients with isolated REM sleep behaviour disorder (17 males, age range: 54–77 years) and 25 healthy matched controls (25 males, age range: 58–76 years). Patients and controls were cognitively tested by Montreal Cognitive Assessment and Mini Mental State Examination. Results revealed profound hypoperfusion and microvascular flow disturbances throughout the cortex in patients compared to controls. In patients, the microvascular flow disturbances were seen in cortical areas associated with language comprehension, visual processing and recognition and were associated with impaired cognitive performance. We conclude that cortical blood flow abnormalities, possibly related to impaired neurogenic control, are present in patients with isolated REM sleep behaviour disorder and associated with cognitive dysfunction. We hypothesize that pharmacological restoration of perivascular neurotransmitter levels could help maintain cognitive function in patients with this prodromal phenotype of parkinsonism.

Evaluation of automated microvascular flow analysis software AVA 4: a validation study

Background Real-time automated analysis of videos of the microvasculature is an essential step in the development of research protocols and clinical algorithms that incorporate point-of-care microvascular analysis. In response to the call for validation studies of available automated analysis software by the European Society of Intensive Care Medicine, and building on a previous validation study in sheep, we report the first human validation study of AVA 4. Methods Two retrospective perioperative datasets of human microcirculation videos (P1 and P2) and one prospective healthy volunteer dataset (V1) were used in this validation study. Video quality was assessed using the modified Microcirculation Image Quality Selection (MIQS) score. Videos were initially analyzed with (1) AVA software 3.2 by two experienced investigators using the gold standard semi-automated method, followed by an analysis with (2) AVA automated software 4.1. Microvascular variables measured were perfused vessel density (PVD), total vessel density (TVD), and proportion of perfused vessels (PPV). Bland–Altman analysis and intraclass correlation coefficients (ICC) were used to measure agreement between the two methods. Each method’s ability to discriminate between microcirculatory states before and after induction of general anesthesia was assessed using paired t-tests. Results Fifty-two videos from P1, 128 videos from P2 and 26 videos from V1 met inclusion criteria for analysis. Correlational analysis and Bland–Altman analysis revealed poor agreement and no correlation between AVA 4.1 and AVA 3.2. Following the induction of general anesthesia, TVD and PVD measured using AVA 3.2 increased significantly for P1 (p < 0.05) and P2 (p < 0.05). However, these changes could not be replicated with the data generated by AVA 4.1. Conclusions AVA 4.1 is not a suitable tool for research or clinical purposes at this time. Future validation studies of automated microvascular flow analysis software should aim to measure the new software’s agreement with the gold standard, its ability to discriminate between clinical states and the quality thresholds at which its performance becomes unacceptable.