Quantitative perfusion assessment of gastric conduit with indocyanine green dye to predict anastomotic leak after esophagectomy

Summary Impaired gastric conduit perfusion is a risk factor for anastomotic leak after esophagectomy. The aim of this study is to evaluate the feasibility of intraoperative quantitative assessment of gastric conduit perfusion with indocyanine green fluorescence angiography as a predictor for cervical esophagogastric anastomotic leak after esophagectomy. Indocyanine green fluorescence angiography using the SPY Elite system was performed in patients undergoing a transhiatal or McKeown esophagectomy from July 2015 through December 2020. Ingress (dye uptake) and Egress (dye exit) at two anatomic landmarks (the tip of a conduit and 5 cm from the tip) were assessed. The collected data in the leak group and no leak group were compared by univariate and multivariable analyses. Of 304 patients who were evaluated, 70 patients developed anastomotic leak (23.0%). There was no significant difference in patients’ demographic between the groups. Ingress Index, which represents a proportion of blood inflow, at both the tip and 5 cm of the conduit was significantly lower in the leak group (17.9 vs. 25.4% [P = 0.011] and 35.9 vs. 44.6% [P = 0.019], respectively). Ingress Time, which represents an estimated time of blood inflow, at 5 cm of the conduit was significantly higher in the leak group (69.9 vs. 57.1 seconds, P = 0.006). Multivariable analysis suggested that these three variables can be used to predict future leak. Variables of gastric conduit perfusion correlated with the incidence of cervical esophagogastric anastomotic leak. Intraoperative measurement of gastric conduit perfusion can be predictive for anastomotic leak following esophagectomy.

Evaluation of the efficiency of a new pulsatile flow‑generating circulatory-assist system in rotary blood pumps. Research on a mathematical model

Objective: to study the effect of a pulsatile flow-generation (PFG) device on the basic hemodynamic parameters of the circulatory system using a mathematical model.Results. Modelling and simulation showed that the use of PFG significantly (76%) increases aortic pulse pressure. The proposed mathematical model adequately describes the dynamics of the circulatory system and metabolism (oxygen debt) on physical activity in normal conditions and heart failure, and the use of non-pulsatile and pulsatile circulatory-assist systems. The mathematical model also shows that the use of PFG device blocks the development of rarefaction in the left ventricular cavity associated with a mismatch of blood inflow and outflow in diastolic phase when there is need to increase systemic blood flow by increasing the rotary pump speed.

Hemodynamic Patterns of Spinal Cord Perfusion in Thoracoabdominal Aortic Aneurysm Repair

Paraplegia in aortic surgery is due to its impact on spinal cord perfusion whose hemodynamic patterns (SCPHP) are not clearly defined. Detailed morphological analysis of vascular network and collateral network modifications within Monro–Kellie postulate due to the fixed theca confines was performed to identify SCPHP. SCPHP may begin with intraspinal “backflow” (I-BF), that is, hemorrhage from anterior and posterior spinal arteries, backward via the connected anterior and posterior radicular medullary arteries, through the increasing diameter and decreasing resistance of segmental arteries (SAs), off their aortic orifices outside vascular network at 0 operative field pressure. The I-BF blood bypasses both intra- and extraspinal capillary networks and causes depressurization (0 diastolic pressure) and full ischemia of dependent spinal cord. When the occlusion of those SAs orifices arrests I-BF, the hemodynamic pattern of intraspinal “steal” (I-S) may take place. The formerly I-BF blood, in fact, is now variably shared between the fraction maintained in its physiological intraspinal network and that keeping flowing as I-S through the extraspinal capillary network. I-S is, however, counteracted by the extraspinal “steal” from the connected mammary/paraspinous-independent extraspinal feeders, all physically competing for the same room left by the missed physiological SA direct aortic blood inflow. Steal phenomenon evolves within the 120-hour time frame of CNm, whose intraspinal anatomical changes may offer the physical basis within the Monro–Kelly postulate, respectively of the intraoperative and postoperative paraplegia. The current procedures could not prevent the unphysiological SCPHP but awareness of details of their various features may offer the basis for improvements tailored, to the adopted intra- and postoperative procedures.

Microcirculatory Liver Bloodstream in Hyperhomocysteinemia and Administration of Tautomeric Forms of Orotic Acid

The aim of the study was to analyze the microvasculation of the liver in administration of tautomeric forms of orotic acid for a methionine-induced liver pathology to assess the efficacy of the modified drugs and the potentialof their clinical use.Material and methods. The study included 30 white outbred rats, that were simulated methionine induced hyperhomocysteinemia by the administration of methionine, dosage 0.15 g/100 g of the body we ight, via food during 4 weeks. Animals with hyperhomocysteinemia were divided into 4 groups: animals of group 1 received orotic acid (OA) in the initial form (oxo-tautomer), animals of group 2 received hydroxy–tautomer OA after mechanomodification for 1 hour, animals of group 3 received dihydroxy-tautomer OA after mechanomodification for 6 hours. Histological preparations of the liver were used to evaluate the area of hepatocytes; diameters and areas of the central vein, the interlobular vein and artery, the bile duct, and the Visotto coefficient were calculated.Results. Morphometric data of the hepatic microvascular bloodstream with simulated hyperhomocysteinemia evidenced a general increase in the diameter and area of blood vessels, changes affected the system of blood inflow and outflow at the organ level. Administration of OA had a normalizing effect on the liver bloodflow, but the effects were different: the most pronounced effect was detected in administration of the hydroxy-form of the preparation, this can be explained by a modificationin the dispersion of the preparation (without changing the crystal lattice), an increase in the rate of dissolution in water and aqueous solutions, an increasein the number of functionally active groups in the heterocycle of the hydroxy-form of OA. Thus, the hydroxy-tautomer of orotic acid had the greatest efficacy relating to vasodilation of microvessels of the liver bloodstream in hyperhomocysteinemia; the fact suggesting feasibility of its further study in the clinical environment.

Regression of portal hypertension: underlying mechanisms and therapeutic strategies

Portal hypertension is the main non-neoplastic complication of chronic liver disease, being the cause of important life-threatening events including the development of ascites or variceal bleeding. The primary factor in the development of portal hypertension is a pathological increase in the intrahepatic vascular resistance, due to liver microcirculatory dysfunction, which is subsequently aggravated by extra-hepatic vascular disturbances including elevation of portal blood inflow. Evidence from pre-clinical models of cirrhosis has demonstrated that portal hypertension and chronic liver disease can be reversible if the injurious etiological agent is removed and can be further promoted using pharmacological therapy. These important observations have been partially demonstrated in clinical studies. This paper aims at providing an updated review of the currently available data regarding spontaneous and drug-promoted regression of portal hypertension, paying special attention to the clinical evidence. It also considers pathophysiological caveats that highlight the need for caution in establishing a new dogma that human chronic liver disease and portal hypertension is reversible.

INFLUENCE BLOOD SHARE AND THE LINEAR ACCESSORY ON INDEXES OF DAIRY EFFICIENCY OF COWS

Blood inflow of Holstein breed in Mari El cattle breeding, which began in 80s of the last century, had a positive impact on the dairy productivity of Black-and-White cattle. The research explores the impact of Holstein breed bloodline and lineage on the main indicators of cows’ dairy productivity in OAO Ovoshchevod. The productive age increasing, the live weight of cows in the main herd increased as well while the animals were relatively small. The cows of the eighth and ninth calves had the maximum live weight. On average, the cows with the third complete lactation (6791.5 kg) had the highest milk yield. The mass fraction of fat was on average higher than the basic fraction and was equal to 3.71%. The increase of milk fat concentration was observed in cows of the fifth and sixth lactations, with the offsprings of Black-and-White bull lines being the most fatty. There is a direct correlation between milk yield and the degree of blood flow in the Holstein breed. The fattiest milk cows were those with a blood content of 19%, while the cattle with a blood content of 75% had the lowest fat concentration in milk. According to the hospitalization data, most of the cows in the herd (including the first heifer cows) belong to the R. Sawring line. The female offsprings of Adam, Rikus and M. Chiftein bulls differed in the most productive longevity. The most abundant were cows belonging to M. Chiftein line. Female offsprings of Black-and-White bulls were inferior to the Holstein ones in average by 324 kg of milk. This feature was traced from first to fifth lactation. In the lactation section, the most fatty-milk cows of the Rikus and M. Chiftein lines were the fattest. As the share of blood in the Holstein breed increased, the milk yield per cow in the main herd increased as well. Thus, for cows with blood content of 18.75%, the average milk yield for all lactations was 6313 kg of milk. Further blood inflow of Holstein bulls led to this parameter increasing by 4% on average for cows with blood content of 25 and 37.5% for Holstein breed.

High spatiotemporal vessel-specific hemodynamic mapping with multi-echo single-vessel fMRI

High-resolution fMRI enables noninvasive mapping of the hemodynamic responses from individual penetrating vessels in animal brains. Here, a 2D multi-echo single-vessel fMRI (MESV-fMRI) method has been developed to map the fMRI signal from arterioles and venules with a 100 ms sampling rate at multiple echo times (TE, 3–30 ms) and short acquisition windows (<1 ms). The T2*-weighted signal shows the increased extravascular effect on venule voxels as a function of TE. In contrast, the arteriole voxels show an increased fMRI signal with earlier onset than venules voxels at the short TE (3 ms) with increased blood inflow and volume effects. MESV-fMRI enables vessel-specific T2* mapping and presents T2*-based fMRI time courses with higher contrast-to-noise ratios (CNRs) than the T2*-weighted fMRI signal at a given TE. The vessel-specific T2* mapping also allows semi-quantitative estimation of the oxygen saturation levels (Y) and their changes (ΔY) at a given blood volume fraction upon neuronal activation. The MESV-fMRI method enables vessel-specific T2* measurements with high spatiotemporal resolution for better modeling of the fMRI signal based on the hemodynamic parameters.

Intraoperative Hepatic Blood Inflow Can Predict Early Acute Kidney Injury following DCD Liver Transplantation: A Retrospective Observational Study

Purpose. Acute kidney injury (AKI) is a major and severe complication following donation-after-circulatory-death (DCD) liver transplantation (LT) and is associated with increased postoperative morbidity and mortality. However, the risk factors and the prognosis factors of AKI still need to be further explored, and the relativity of intraoperative hepatic blood inflow (HBI) and AKI following LT has not been discussed yet. The purpose of this study was to investigate the correlation between HBI and AKI and to construct a prediction model of early acute kidney injury (EAKI) following DCD LT with the combination of HBI and other clinical parameters. Methods. Clinical data of 132 patients who underwent DCD liver transplantation at the first hospital of China Medical University from April 2005 to March 2017 were analyzed. Data of 105 patients (the first ten years of patients) were used to develop the prediction model. Then we assessed the clinical usefulness of the prediction models in the validation cohort (27 patients). EAKI according to Kidney Disease Improving Global Outcomes (KDIGO) criteria based on serum creatinine increase during 7-day of postoperative follow-up. Results. After Least Absolute Shrinkage and Selection Operator (LASSO) regression and simplification, a simplified prediction model consisting of the Child-Turcotte-Pugh (CTP) score (p=0.033), anhepatic phase (p=0.014), packed red blood cell (pRBC) transfusion (p=0.027), and the HBI indexed by height (HBI/h) (p=0.002) was established. The C-indexes of the model in the development and validation cohort were 0.823 [95% CI, 0.738-0.908] and 0.921 [95% CI, 0.816-1.000], respectively. Conclusions. In this study, we demonstrated the utility of HBI/h as a predictor for EAKI following DCD LT, as well as the clinical usefulness of the prediction model through the combination of the CTP score, anhepatic phase, pRBC transfusion and HBI/h.