Assessment Of Microcirculation Research Articles

Coronary Microvascular Dysfunction.

Many patients with chest pain undergoing coronary angiography do not show significant obstructive coronary lesions. A substantial proportion of these patients have abnormalities in the function and structure of coronary microcirculation due to endothelial and smooth muscle cell dysfunction. The coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac oxygen requirements. Impairment of this mechanism, defined as coronary microvascular dysfunction (CMD), carries an increased risk of adverse cardiovascular clinical outcomes. Coronary endothelial dysfunction accounts for approximately two-thirds of clinical conditions presenting with symptoms and signs of myocardial ischemia without obstructive coronary disease, termed “ischemia with non-obstructive coronary artery disease” (INOCA) and for a small proportion of “myocardial infarction with non-obstructive coronary artery disease” (MINOCA). More frequently, the clinical presentation of INOCA is microvascular angina due to CMD, while some patients present vasospastic angina due to epicardial spasm, and mixed epicardial and microvascular forms. CMD may be associated with focal and diffuse epicardial coronary atherosclerosis, which may reinforce each other. Both INOCA and MINOCA are more common in females. Clinical classification of CMD includes the association with conditions in which atherosclerosis has limited relevance, with non-obstructive atherosclerosis, and with obstructive atherosclerosis. Several studies already exist which support the evidence that CMD is part of systemic microvascular disease involving multiple organs, such as brain and kidney. Moreover, CMD is strongly associated with the development of heart failure with preserved ejection fraction (HFpEF), diabetes, hypertensive heart disease, and also chronic inflammatory and autoimmune diseases. Since coronary microcirculation is not visible on invasive angiography or computed tomographic coronary angiography (CTCA), the diagnosis of CMD is usually based on functional assessment of microcirculation, which can be performed by both invasive and non-invasive methods, including the assessment of delayed flow of contrast during angiography, measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), evaluation of angina induced by intracoronary acetylcholine infusion, and assessment of myocardial perfusion by positron emission tomography (PET) and magnetic resonance (CMR).

Intraoperative Imaging of Cortical Blood Flow by Camera-Based Photoplethysmography at Green Light

Intraoperative evaluation of blood perfusion in the brain cortex is an important but hitherto unresolved problem. Our aim was to demonstrate the feasibility of cerebral microcirculation assessment during open brain surgery by using camera-based photoplethysmography (cbPPG) synchronized with an electrocardiograph. Cortical blood flow was monitored in five patients with different diagnoses. Two cases (tumor resection and extra-intracranial bypass grafting) are presented in detail. Blood-flow parameters were visualized after processing cortex images recorded under green-light illumination before and after surgical intervention. In all cases, blood flow was successfully visualized in >95% of open brain. Distributions of blood pulsation amplitude, a parameter related to cortical blood perfusion; pulse arrival time; and blood-pressure-pulse shape were calculated with high spatial resolution (in every pixel). Changes in cerebral blood supply caused by surgical intervention were clearly revealed. We have shown that the temporal spread of pulse arrival time and the spatiotemporal variability of pulse shape are very sensitive markers of brain circulatory disturbances. The green-light cbPPG system offers a new approach to objective assessment of blood-flow changes in the brain during surgical intervention. The proposed system allows for contactless monitoring of cortex blood flow in real time with high resolution, thus providing useful information for surgery optimization and minimization of brain tissue damage.

Early Sequential Microcirculation Assessment In Shocked Patients as a Predictor of Outcome: A Prospective Observational Cohort Study.

A dysfunctional microcirculation is universal in shock and is often dissociated from global hemodynamic parameters. Persistent microcirculatory derangements reflect ongoing tissue hypoperfusion and organ injury. The initial microcirculatory dysfunction and subsequent resolution could potentially guide therapy and predict outcomes. We evaluated the microcirculation early in a heterogenous shocked population. Microcirculatory resolution was correlated with measures of tissue perfusion and global hemodynamics. The relationship between the microcirculation over 24 h and outcome were evaluated. We prospectively recruited patients with all forms of shock, based on global hemodynamics and evidence of organ hypoperfusion. A 30-bed adult intensive care unit (ICU). Eighty-two shocked patients. Following the diagnosis of shock, patients underwent a sublingual microcirculation examination using Sidestream Dark Field Imaging. The median age of patients was 66 years old (interquartile range [IQR] 54-71), with an Acute Physiology and Chronic Health Evaluation II of 27 (IQR 20-32). Microcirculatory parameters included Percentage Perfused Vessels (PPV), De Backer Score, and a heterogeneity index in patients with septic shock, according to the second consensus guidelines Additional parameters collected: temperature, heart rate and arterial pressure, cumulative fluid balance, and vasopressor use. Arterial blood samples were taken at the time of microcirculatory assessments, providing HCO3, lactate concentrations, PaO2, and PaCO2 measurements. A statistically significant improvement in PPV and the heterogeneity index was demonstrated. This improvement was mirrored by biomarkers of perfusion; however, the global hemodynamic parameter changes were not significantly different over the 24-h period. The early microcirculatory improvement was not predictive of an improvement in acute kidney injury, length of stay, ICU, or hospital mortality. Early sequential evaluation of the microcirculation in shocked patients, demonstrated statistically significant improvement in the PPV and microvascular heterogeneity with standard care. These improvements were mirrored by biomarkers of organ perfusion; however, the changes in global hemodynamics were not as pronounced in this early phase. Early improvement in the microcirculation did not predict clinical outcome.

Objective assessment of skin microcirculation using a smartphone camera.

Existing techniques for assessment of microcirculation are limited by their large size and high costs and are often not so easy to use. Advances in mobile technology have enabled great improvements in smartphone sensor technology. In this study, we used SkinSight, an app for iPhone and iPad, to measure changes in skin microcirculation during physiological provocations. The system estimates changes in the concentration of hemoglobin in the skin by analyzing the reflected light emitted from the built-in light-emitting diode and detected by the camera of the smartphone. A relative hemoglobin (Hb) index was measured during a 5-min arterial occlusion, post-occlusive reactive hyperemia, and a 5-min venous occlusion in 10 healthy subjects, on two separate days. The index was calculated in an area of the skin from the color information in the images acquired by the phone camera. Polarized light spectroscopy imaging was used to measure changes in red blood cell concentration for comparison. During arterial occlusion, relative Hb index was unchanged compared to baseline (P = .40). After release of the cuff, a sudden 60%-75% increase in Hb index was observed (P < .001) followed by a gradual return to baseline. During venous occlusion, Hb index increased by 80% (P < .001) followed by a gradual decrease to baseline after reperfusion. Day-to-day reproducibility of the relative Hb index was excellent (ICC: 0.92, r = 0.94), although relative Hb index was consistently higher during the second day, possibly as a result of changed lighting conditions or calibration issues. Microvascular responses to physiological provocations in the skin can be accurately and reproducibly measured using a smartphone application. Although the system offers a handheld, easy to use and flexible technique for skin microvascular assessment, the effects of lighting on the measured values and need for calibration need to be further investigated.

A pilot trial to evaluate the clinical usefulness of contrast-enhanced ultrasound in predicting renal outcomes in patients with acute kidney injury.

Contrast-enhanced ultrasound (CEUS) enables the assessment of real-time renal microcirculation. This study investigated CEUS-driven parameters as hemodynamic predictors for renal outcomes in patients with acute kidney injury (AKI). Forty-eight patients who were diagnosed with AKI were prospectively enrolled and underwent CEUS at the occurrence of AKI. Parameters measured were the wash-in slope (WIS), time to peak intensity, peak intensity (PI), area under the time-intensity curve (AUC), mean transit time (MTT), time for full width at half maximum, and rise time (RT). The predictive performance of the CEUS-driven parameters for Kidney Disease Improving Global Outcomes (KDIGO) AKI stage, initiation of renal replacement therapy (RRT), AKI recovery, and chronic kidney disease (CKD) progression was assessed. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of CEUS. Cortical RT (Odds ratio [OR] = 1.21) predicted the KDIGO stage 3 AKI. Cortical MTT (OR = 1.07) and RT (OR = 1.20) predicted the initiation of RRT. Cortical WIS (OR = 76.23) and medullary PI (OR = 1.25) predicted AKI recovery. Medullary PI (OR = 0.78) and AUC (OR = 1.00) predicted CKD progression. The areas under the ROC curves showed reasonable performance for predicting the initiation of RRT and AKI recovery. The sensitivity and specificity of the quantitative CEUS parameters were 60-83% and 62-77%, respectively, with an area under the curve of 0.69-0.75. CEUS may be a supplemental tool in diagnosing the severity of AKI and predicting renal prognosis in patients with AKI.

Assessment of sublingual microcirculation in critically ill patients: consensus and debate.

The main concern in shock and resuscitation is whether the microcirculation can carry adequate oxygen to the tissues and remove waste. Identification of an intact coherence between macro- and microcirculation during states of shock and resuscitation shows a functioning regulatory mechanism. However, loss of hemodynamic coherence between the macro and microcirculation can be encountered frequently in sepsis, cardiogenic shock, or any hemodynamically compromised patient. This loss of hemodynamic coherence results in an improvement in macrohemodynamic parameters following resuscitation without a parallel improvement in microcirculation resulting in tissue hypoxia and tissue compromise. Hand-held vital microscopes (HVMs) can visualize the microcirculation and help to diagnose the nature of microcirculatory shock. Although treatment with the sole aim of recruiting the microcirculation is as yet not realized, interventions can be tailored to the needs of the patient while monitoring sublingual microcirculation. With the help of the newly introduced software, called MicroTools, we believe sublingual microcirculation monitoring and diagnosis will be an essential point-of-care tool in managing shock patients.

Interpatient heterogeneity in hepatic microvascular blood flow during vascular inflow occlusion (Pringle manoeuvre).

Vascular inflow occlusion (VIO) during liver resections (Pringle manoeuvre) can be applied to reduce blood loss, however may at the same time, give rise to ischemia-reperfusion injury (IRI). The aim of this study was to assess the characteristics of hepatic microvascular perfusion during VIO in patients undergoing major liver resection. Assessment of hepatic microcirculation was performed using a handheld vital microscope (HVM) at the beginning of surgery, end of VIO (20 minutes) and during reperfusion after the termination of VIO. The microcirculatory parameters assessed were: functional capillary density (FCD), microvascular flow index (MFI) and sinusoidal diameter (SinD). A total of 15 patients underwent VIO; 8 patients showed hepatic microvascular perfusion despite VIO (partial responders) and 7 patients showed complete cessation of hepatic microvascular perfusion (full responders). Functional microvascular parameters and blood flow levels were significantly higher in the partial responders when compared to the full responders during VIO (FCD: 0.84±0.88 vs. 0.00±0.00 mm/mm2, P<0.03, respectively, and MFI: 0.69-0.22 vs. 0.00±0.00, P<0.01, respectively). An interpatient heterogeneous response in hepatic microvascular blood flow was observed upon VIO. This may explain why clinical strategies to protect the liver against IRI lacked consistency.

Angiography-derived index of microcirculatory resistance as a novel, pressure-wire-free tool to assess coronary microcirculation in ST elevation myocardial infarction

Immediate assessment of coronary microcirculation during treatment of ST elevation myocardial infarction (STEMI) may facilitate patient stratification for targeted treatment algorithms. Use of pressure-wire to measure the index of microcirculatory resistance (IMR) is possible but has inevitable practical restrictions. We aimed to develop and validate angiography-derived index of microcirculatory resistance (IMRangio) as a novel and pressure-wire-free index to facilitate assessment of the coronary microcirculation. 45 STEMI patients treated with primary percutaneous coronary intervention (pPCI) were enrolled. Immediately before stenting and at completion of pPCI, IMR was measured within the infarct related artery (IRA). At the same time points, 2 angiographic views were acquired during hyperaemia to measure quantitative flow ratio (QFR) from which IMRangio was derived. In a subset of 15 patients both IMR and IMRangio were also measured in the non-IRA. Patients underwent cardiovascular magnetic resonance imaging (CMR) at 48 h for assessment of microvascular obstruction (MVO). IMRangio and IMR were significantly correlated (ρ: 0.85, p < 0.001). Both IMR and IMRangio were higher in the IRA rather than in the non-IRA (p = 0.01 and p = 0.006, respectively) and were higher in patients with evidence of clinically significant MVO (> 1.55% of left ventricular mass) (p = 0.03 and p = 0.005, respectively). Post-pPCI IMRangio presented and area under the curve (AUC) of 0.96 (CI95% 0.92–1.00, p < 0.001) for prediction of post-pPCI IMR > 40U and of 0.81 (CI95% 0.65–0.97, p < 0.001) for MVO > 1.55%. IMRangio is a promising tool for the assessment of coronary microcirculation. Assessment of IMR without the use of a pressure-wire may enable more rapid, convenient and cost-effective assessment of coronary microvascular function.

Assessment of microcirculation of intact periodontal tissues in children using laser doppler flowmetry

In dentistry, the method of laser flowmetry (LDF) is used to assess the microcirculatory changes of the oral cavity in normal and pathological conditions. This method is simple and atraumatic, which allows us to quickly and reliably carry out functional diagnostics. LDF is also widely used in related disciplines. The purpose of this review is to assess the microcirculation of intact periodontal tissues in children.

Microscope-type laser speckle contrast imaging for in vivo assessment of microcirculation

Laser speckle contrast imaging (LSCI) can be used to observe dynamic changes in the tissue microcirculation in vivo according to the dynamic interaction between red blood cells and coherent light. In this study, a dual-wavelength LSCI system based on a microscope was developed for in vivo observation of the microvascular pattern and measurement of the blood flow change in the animal model. Additionally, based on the dual-wavelength setup, including 635 and 855 nm wavelengths, the oxygenation of biological tissue was evaluated. Finally, the developed LSCI microscope was implemented for the studies of tissue microcirculation. The results indicate that the developed LSCI microscope could be a potential tool for in vivo observation of the tissue microcirculation and quantitative evaluation of hemodynamics in animal experiments.

Can goal-directed fluid therapy decrease the use of blood and hemoderivates in surgical patients?

The purpose of goal-directed therapy (GDT) is to improve patient outcome by the optimization of hemodynamic status, as it is considered that many perioperative complications are related to microcirculatory disturbance due to an imbalance between oxygen delivery and consumption. The application of GDT protocols incorporating the assessment and optimization of patients' intravascular status should theoretically lead to a reduction in perioperative bleeding and transfusion requirements, as both hypervolemia and hypovolemia and their consequences such as dilutional coagulopathy, anemia and inadequate oxygen delivery to the tissues are avoided. However, the research reporting decreased usage of blood products in patients which received targeted fluid management is sparse; decreased blood loss and transfusion requirements were reported in spine surgery using GDT, while studies in abdominal or cardiac surgery did not consistently report significant decreases in blood products transfusion when GDT were applied. These heterogenous results reported can be explained by the differences between the GDT protocols used, as the differences in therapeutic goals can impact on blood transfusion requirements. In the future, the GDT protocols should include not only the prediction of fluid responsiveness and optimization of hemodynamic status, but also the assessment of microcirculation and measures to improve tissue oxygenation, parameters which can also guide the decision for blood product transfusion. A better standardization of GDT algorithms is also required in order to perform a more accurate assessment of the effects of applying GDT on the consumption of blood products.

Twenty Years of Cerebral Ultrasound Perfusion Imaging-Is the Best yet to Come?

Over the past 20 years, ultrasonic cerebral perfusion imaging (UPI) has been introduced and validated applying different data acquisition and processing approaches. Clinical data were collected mainly in acute stroke patients. Some efforts were undertaken in order to compare different technical settings and validate results to gold standard perfusion imaging. This review illustrates the evolution of the method, explicating different technical aspects and milestones achieved over time. Up to date, advancements of ultrasound technology as well as data processing approaches enable semi-quantitative, gold standard proven identification of critically hypo-perfused tissue in acute stroke patients. The rapid distribution of CT perfusion over the past 10 years has limited the clinical need for UPI. However, the unexcelled advantage of mobile application raises reasonable expectations for future applications. Since the identification of intracerebral hematoma and large vessel occlusion can also be revealed by ultrasound exams, UPI is a supplementary multi-modal imaging technique with the potential of pre-hospital application. Some further applications are outlined to highlight the future potential of this underrated bedside method of microcirculatory perfusion assessment.

Normative data and the influence of age and sex on microcirculatory function in a middle-aged cohort: results from the SCAPIS study

The objective of this study was to assess normative values for comprehensive forearm skin microcirculatory function: oxygen saturation, tissue fraction of red blood cells (RBCs), and speed-resolved perfusion. Furthermore, to examine the influence of age and sex on microcirculatory function. Measurements were performed using a noninvasive probe-based system, including diffuse reflectance spectroscopy and laser-Doppler flowmetry, yielding output data in absolute units. The study was conducted within the Swedish CArdioPulmonary BioImage Study (SCAPIS) and included 1,765 men and women aged 50-65 yr from the Linköping general population. Normative values are given at baseline, at the end of a 5-min occlusion of the brachial artery and during hyperemia after occlusion release. We found a consistent age distribution, in which the oldest individuals had the lowest peak oxygen saturation (P < 0.001) and the highest baseline low-speed perfusion (P < 0.001). Women had higher peak oxygen saturation (P < 0.001), lower RBC tissue fraction, in general (P < 0.001), lower baseline perfusion in all speed regions (P = 0.01), and lower peak high-speed perfusion at hyperemia (P < 0.001). The normative data can be used as reference values in future studies of disease-specific populations. The results show that age and sex are important aspects to consider in studies of microvascular function. Women and younger age were factors associated with higher peak oxygen saturation after ischemia. This is a novel parameter that reflects overall microcirculatory function associated with vascular dilation capacity.NEW & NOTEWORTHY This study expands experimental microcirculatory research to clinical use by providing normative values on microcirculatory function in a large population-based cohort. Women and younger age were factors associated with higher peak oxygen saturation after ischemia, which implies that age and sex are important aspects to consider in studies of microvascular function. This study is the first step toward using microcirculatory assessment as a tool to improve diagnosis, prognosis, and treatment in disease-specific populations.

Indices of Tissue Perfusion: Triggers of Targets of Resuscitation?

Circulatory shock is characterized by a decrease in oxygen delivery to the tissues associated with impairment in oxygen metabolism and tissue hypoxia. Clinical and biological signs of impaired tissue perfusion and tissue hypoxia are used as bedside to detect circulatory failure and trigger resuscitation procedures. The most popular signs of tissue hypoperfusion include mean arterial pressure, capillary refill time and mottling score, central venous oxygen saturation (ScvO2), veno-arterial difference in PCO2 (PvaCO2), microcirculation assessment, and lactate. Both the severity and duration of the alterations in any of these variables are associated with a poor outcome so that it sounds logical to trigger therapy based on these. Using these variables as target for therapy is much more complex. Some of the limits for using some of these variables as targets include an incertitude about the target to reach (should we aim at normalizing or improving the variable, and by how much?) and the time lag between resolution of impaired tissue perfusion/hypoxia and normalization of the variable. The ideal target variable should have a well-defined end point and a rapid response time. Interestingly, hemodynamic resuscitation targeting these variables gave variable results. In this review, we will discuss the interest and limitations of the above-mentioned indices of tissue perfusion and hypoxia as trigger as well as end point of resuscitation in critically ill patients.

Invasive Assessment of the Myocardial Microcirculation during Beating Heart Coronary Artery Bypass Grafting.

Coronary artery bypass grafting may be associated with several cardiac complications, including ischemia, acute myocardial infarction, arrhythmias, or hemodynamic instability. Accumulating evidence suggests that well-developed coronary collateral circulation may protect against adverse effects, including myocardial ischemia. Assessment of myocardial microvascular perfusion is, therefore, of great clinical interest in beating heart surgery. In this paper, myocardial microvascular perfusion is continuously assessed on the beating heart using laser Doppler flowmetry in consecutive patients who underwent coronary artery bypass grafting procedures. No significant (p = 0.110) differences were found between the averaged perfusion signal (n = 42) at the baseline, during artery occlusion, or after reperfusion (732.4 ± 148.0 vs. 711.4 ± 144.1 vs. 737.0 ± 141.2, respectively). In contrast, significantly different (p < 0.001) mean perfusion signals (n = 12) were found (805.4 ± 200.1 vs. 577.2 ± 212.8 vs. 649.3 ± 220.8) in a subset of patients who presented with hemodynamic instability and myocardial ischemia. Additionally, a strong positive correlation between the plasma levels of high-sensitivity troponin I and perfusion decrease level after artery occlusion was found (r = 0.854, p < 0.001). This study argues that myocardial microvascular perfusion remains constant during coronary artery bypass grafting on the beating heart in advanced coronary artery disease. This phenomenon is most likely due to an extensive coronary collateral circulation.

Microcirculatory assessment of vascular diseases.

The term "microcirculation" refers to the terminal vascular network of the body, which includes arterioles, capillaries, venules as well as initial lymphatic vessels. Additionally, it insinuates to their unique function in thermoregulation, fluid balance, maintenance of cellular exchange, and metabolism. Disturbances of microvascular function were identified to precede macrovascular involvement in the presence of cardiovascular risk factors and is the hallmark of terminal disease stages like critical limb or acral ischemia. Nevertheless, despite its obvious significance in vascular medicine assessment of microvascular function became increasingly neglected in the clinical institutions during the last decades and seems to play a subordinary role in medical education. We therefore provide an overview over relevant and clinically practicable methods to assess microcirculation in vascular medicine with critical estimations of their pros and cons and their perspectives in the future.

The Relationship Between 99mTc-Pertechnetate Hand Perfusion Scintigraphy and Nailfold Capillaroscopy in Systemic Sclerosis Patients: A Pilot Study.

Objectives This study aims to assess the possible relationship between 99mTc-pertechnetate hand perfusion scintigraphy (HPS) and nailfold capillaroscopy (NC) in systemic sclerosis (SSc) patients.Patients and methods The study group consisted of 25 SSc patients (6 males; 19 females; mean age 54.2±9.7 years; range, 32 to 67 years), 18 female patients with primary Raynaud's phenomenon (PRP) (mean age 47.1±9.5 years; range, 34 to 65 years) and 10 healthy individuals (3 males, 7 females; mean age 52.7±12.6 years; range, 37 to 73 years). NC and 99mTc-pertechnetate HPS were performed in all examinees. The capillaroscopic findings were classified as normal or scleroderma pattern ("early", "active", or "late"). The fingers-to-palm ratios were calculated for both blood flow (BF) and blood pool (BP) phases of the 99mTc-pertechnetate HPS.Results Systemic sclerosis patients showed a significantly lower BP ratio than PRP patients and healthy subjects (p=0.004). No statistically significant difference was observed between the SSc and PRP patients in respect to BF ratio. A gradual decrease of BF and BP with the severity of NC microangiopathy pattern ("early", "active" or "late") was found in SSc patients, while the differences were not statistically significant. Patients with diffuse SSc showed lower BF and higher BP than those with limited SSc, while these differences were without statistical significance. There was no significant correlation between BF or BP values and type of SSc (limited or diffuse) (p=0.77 versus p=0.54, respectively) as well as three microangiopathy patterns (p=0.22 versus p=0.54, respectively).Conclusion 99mTc-pertechnetate HPS improves the evaluation of vascular damage in SSc patients. There is no direct relationship between NC and 99mTc-pertechnetate HPS; however, the two methods complement each other in the assessment of microcirculation in SSc.

Functional and Structural Reliability of Optic Nerve Head Measurements in Healthy Eyes by Means of Optical Coherence Tomography Angiography.

Background and Objectives: the aim of the study was to evaluate the repeatability and reproducibility of optical microangiography (OMAG)-based optical coherence tomography angiography (OCTA) in the optic nerve head (ONH) and radial peripapillary capillary (RPC) perfusion assessment of healthy eyes. Materials and Methods: in this observational study, a total of 40 healthy subjects underwent ONH evaluation, using an OMAG-based OCTA system at baseline (T0), after 30 min (T1), and after 7 days (T2). The main outcome measures were the vessel density (VD) and flux index (FI) of the RPCs, as well as peri-papillary retinal nerve fibre layer (pRNFL) thickness. The analysis was performed by two observers independently. The coefficient of repeatability (CR), within the subject coefficient of variation (CVw) and intrasession correlation coefficient (ICC), to evaluate intrasession repeatability of measurements was calculated for each observer. Results: the high intrasession and intersession repeatability and reproducibility were assessed in the two observers for all three outcome measures. Of note, the CRs for the first and the second observer were 0.011 (95% confidence interval (CI) 0.009–0.014) and 0.016 (95% CI 0.013–0.020) for FI, 0.016 (95% CI 0.013–0.021) and 0.017 (95% CI 0.014–0.021) for VD, and 2.400 (95% CI 1.948–3.092) and 3.732 (95% CI 3.064–4.775) for pRNFL thickness, respectively. The agreement between them was excellent for pRNFL assessment and very good for FI and VD. Conclusion: OCTA has a great potential in the accurate assessment of ONH and peri-papillary microcirculation. It allows for repeated and reproducible measurements without multiple scans-related bias, thus guaranteeing an independent operator analysis with good reproducibility and repeatability.

Evaluation of a shorter algorithm in an automated analysis of sublingual microcirculation.

Diagnostic and risk stratification in intensive and emergency medicine must be fast, accurate, and reliable. The assessment of sublingual microcirculation is a promising tool for this purpose. However, its value is limited because the measurement is time-consuming in unstable patients. This proof-of-concept validation study examines the non-inferiority of a reduced frame rate in image acquisition regarding quality, measurement results, and time. This prospective observational study included healthy volunteers. Sublingual measurement of microcirculation was performed using a sidestream dark field camera (SDF, MicroVision Medical®). Video-quality was evaluated with a modified MIQS (microcirculation image quality score). AVA 4.3C software calculated microcirculatory parameters. Thirty-one volunteers were included. There was no impact of the frame rate on the time needed by the software algorithm to measure one video (4.5 ± 0.5 minutes) for AVA 4.3C. 86 frames per video provided non inferior video quality (MIQS 1.8 ± 0.7 for 86 frames versus MIQS 2.2 ± 0.6 for 215 frames, p < 0.05), equal results for all microcirculatory parameters, but did not result in an advantage in terms of speed. No complications occurred. Video captures with 86 frames offer equal video quality and results for consensus parameters compared to 215 frames. However, there was no advantage regarding the time needed for the overall measurement procedure.

NEUTROPHIL-LYMPHOCYTE RATIO AND PLATELET-LYMPHOCYTE RATIO AS PREDICTORS OF CORONARY MICROCIRCULATORY DISEASE OCCURRENCE AND OUTCOME IN PATIENTS WITH CHRONIC CORONARY SYNDROME AND NO SIGNIFICANT CORONARY ARTERY STENOSIS

Introduction: Index of microcirculatory resistance assessment is an invasive method of measuring coronary microcirculation function. Association between impaired microcirculatory function and higher rate of cardiovascular events was proven. Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio seem to be a promising parameters to predict coronary microcirculatory disease in patients with chronic coronary syndrome. The aim: To determine neutrophil-lymphocyte ratio and platelet-lymphocyte ratio levels in patients with coronary microcirculatory disease and potential association with clinical outcome. Material and methods: 82 consecutive patients with mean age of 67 years, 67% male, were tested for presence of coronary microcirculatory disease using index of microcirculatory resistance. Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were calculated based on admission full blood count. Follow-up with major adverse cardiac and cardiovascular events registration was performed (median 24 months). Results: The study showed significantly higher neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in patients with coronary microcirculatory disease compared to control group (3.58±2.61 vs 2.54±1.09 and 164±87.9 vs 124±36.6 respectively). Higher level of platelet-lymphocyte ratio in patients with coronary microcirculatory disease results in worse MACCE-free survival. Optimal cut-off values of neutrophil-lymphocyte ratio and platelet-lymphocyte ratio to detect coronary microcirculatory disease were 3.2 and 181.3, respectively. Conclusions: Higher neutrophil-lymphocyte ratio and platelet-lymphocyte ratio are associated with increased index of microcirculatory resistance value. Platelet-lymphocyte ratio may be used as a predictor of worse outcome in patients with coronary microcirculatory disease.