Arterial Perfusion Research Articles

Prostatic Artery Perfusion from the Medial Circumflex Femoral Artery

Prostatic Artery Perfusion from the Medial Circumflex Femoral Artery

White-Matter Lesions and Cortical Cerebral Blood Flow Evaluation by 3D Arterial Spin-Labeled Perfusion MRI in Asymptomatic Divers: Correlation with Patent Foramen Ovale Ocurrence.

Cerebral white-matter lesions (cWML) can be caused by dilation of Virchow-Robin spaces or may correspond to true lacunar ischemic lesions. The aim of our study was to evaluate in asymptomatic divers the relationship between the presence of patent foramen ovale (PFO) and cWML, as well as their possible effects on cortical cerebral blood flow (CBF) by magnetic resonance (MRI) through the arterial spin labeling (ASL) sequence. Transthoracic echocardiography was performed for the identification of PFO, and cerebral magnetic resonance including the 3D-ASL sequence for CBF quantification. Thirty-eight divers, with a mean age 45.8 ± 8.6 years, were included. Nineteen healthy volunteers, mean age 41 ± 15.2 years, served as the control group. A total of 28.9% of divers had completed more than 1000 dives. It was found that 26.3% of divers presented with PFO in the echocardiographic study. cWML was evidenced in 10.5% of diver MRI studies. There was no statistically significant relationship between the presence of PFO and cWML (p = 0.95). We observed a lower blood flow in all brain areas assessed by the 3D-ASL sequence in the group of divers, compared with the control group. We did not find statistical differences in CBF as a function of the presence or absence of PFO, number of dives, or cWML evidence.

Brain Tumor Vascularity Estimation by Arterial Spin Label Perfusion MRI—A Preoperative Tool for Patient Prognostication

Abstract Introduction Brain tumors remain a significant cause of morbidity and mortality around the globe. Preoperative estimation of tumor vascularity is of great significance for a neurosurgeon. Aim of our study was to correlate tumor blood flow (TBF) using arterial spin labeling perfusion imaging (ASL-PI) with microvessel density (MVD), tumor grade, and preoperative prognostication of brain tumors. Materials and Methods This was a prospective observational cross-sectional study conducted in 63 patients of primary brain tumors already referred for magnetic resonance imaging. Absolute and relative mean and maximum TBF were calculated using ASL-PI and correlated with tumor grade and MVD at 10x and 40x magnificantion; thereby stydying the role of ASL-PI in brain tumor prognostication. Results The mean of maxTBF values (mL/min/100 g) in the gliomas group, meningiomas group, schwannoma group, craniopharyngioma group, and hemangioblastoma group was 147.15, 251.55, 96.43, 43.3, and 578.3, respectively. The median of maxTBF value in the gliomas group, meningiomas group, schwannoma group, craniopharyngioma group, and hemangioblastoma group was 131.5, 158.63, 94.5, 43.4, and 578.3, respectively. Discussion Significant correlation between meanTBF and MVD at 10X magnification (p-value < 0.001, rho =0.88) and a positive correlation between meanTBF and MVD at 40X magnification (p-value < 0.001) were seen. Significant correlation was also seen between maxTBF and MVD at 10X magnification (p-value < 0.001, rho = 0.91) and between maxTBF and MVD at 40X magnification. TBF in case of the hemangioblastoma was higher than other types of brain tumors (gliomas, meningiomas, and schwannomas). HighTBF value was seen in high-grade gliomas compared with low-grade gliomas with worse prognosis. TBF was high in typical meningiomas whereas low in atypical meningioma. Conclusion TBF by ASL-PI can be considered a noninvasive in vivo marker in predicting the grade of brain tumors and further assist in envisaging prognosis of the patients with brain tumors.

Systematic Innominate Artery Cannulation Strategy in Acute Type A Aortic Dissection: Better Perfusion, Better Results.

(1) Background: Arterial cannulation in type A acute aortic dissection (TAAAD) is still subject to debate. We describe a systematic approach of using the innominate artery for arterial perfusion (2) Methods: The hospital records of 110 consecutive patients with acute TAAAD operated on between January 2014 and December 2022 were retrospectively analyzed. The effect of the cannulation site on early and late mortality, as well as on cardio-pulmonary perfusion indices (lactate and base excess levels, and cooling and rewarming speed) were investigated. (3) Results: There was a significant difference in early mortality (8.82% vs. 40.79%, p < 0.01) but no difference in long-term survival beyond the first 30 days. Using the innominate artery enabled the use of approximately 20% higher CPB flows (2.73 ± 0.1 vs. 2.42 ± 0.06 L/min/m2 BSA, p < 0.01), which resulted in more rapid cooling (1.89 ± 0.77 vs. 3.13 ± 1.62 min/°C/m2 BSA, p < 0.01), rewarming (2.84 ± 1.36 vs. 4.22 ± 2.23, p < 0.01), lower mean base excess levels during CPB (-5.01 ± 2.99 mEq/L vs. -6.66 ± 3.37 mEq/L, p = 0.01) and lower lactate levels at the end of the procedure (4.02 ± 2.48 mmol/L vs. 6.63 ± 4.17 mmol/L, p < 0.01). Postoperative permanent neurologic insult (3.12% vs. 20%, p = 0.02) and acute kidney injury (3.12% vs. 32.81%, p < 0.01) were significantly reduced. (4) Conclusions: systematic use of the innominate artery enables better perfusion and superior results in TAAAD repair.

Ultrasonographic classification of 26 cases of fetal umbilical-portal-systemic venous shunts and the correlations with fetal chromosomal abnormalities

ObjectiveTo investigate the ultrasonographic classification of fetal umbilical-portal-systemic venous shunts (UPSVS) and the correlations with fetal chromosomal abnormalities.MethodsWe retrospectively analyzed the ultrasound characteristics and the corresponding chromosomal abnormalities of 26 cases of fetal UPSVS prenatally diagnosed.ResultsA total of 26 fetuses diagnosed as UPSVS were included, including four cases of type I UPSVS, ten of type II, three of type IIIA, and nine of type IIIB. Four cases of type I were all complicated by fetal heart enlargement and heart insufficiency, of which one case had multiple malformations, and all four cases terminated pregnancies. Six of ten cases of type II terminated pregnancies, including four of Down’s syndrome, one of twin reversed arterial perfusion sequence, one of fetal edema but with normal copy number variation (CNV) by chorionic villus sampling. The other four of ten cases were isolated type II with normal chromosomes, which were delivered at full term and were normal in growth and development when followed up 34 months after birth. Three cases of type IIIA all terminated pregnancies, of which one had multiple malformations, one had right multicystic dysplastic kidney, and one had fetal heart enlargement and heart failure. Among nine of type IIIB, seven with chromosomal abnormalities and/ or complicated malformations terminated pregnancies, and two with isolated type IIIB and normal chromosomes were delivered at full term, and were normal in growth and development (one was followed up to 33 months after birth and the other 20 months after birth).ConclusionFetal UPSVS can be clearly diagnosed and typed by prenatal ultrasonography. Fetal prognosis is determined by the types of UPSVS and complicated malformations and/ or chromosomal abnormalities. The probability of fetal chromosomal abnormalities in UPSVS fetuses is related to the ultrasonographic classification.

MASSIVE BONE ALLOGRAFT DECELLULARIZATION BY A PERFUSION PROTOCOL SET UP FOR A BIOCOMPATIBLE MODEL

The purpose of this study is to enhance massive bone allografts osseointegration used to reconstruct large bone defects. These allografts show &gt;50% complication rate requiring surgical revision in 20% cases. A new protocol for total bone decellularisation exploiting the vasculature can offer a reduction of postoperative complication by annihilating immune response and improving cellular colonization/ osseointegration.The nutrient artery of 18 porcine bones - humerus/femur/radius/ulna - was cannulated. The decellularization process involved immersion and sequential perfusion with specific solvents over a course of one week. Perfusion was realized by a peristaltic pump (mean flow rate: 6ml/min). The benefit of arterial perfusion was compared to a control group kept in immersion baths without perfusion.Bone samples were processed for histology (HE, Masson's trichrome and DAPI for cell detection), immunohistochemistry (IHC : Collagen IV/elastin for intraosseous vascular system evaluation, Swine Leukocyte Antigen – SLA for immunogenicity in addition to cellular clearance) and DNA quantification. Sterility and solvent residues in the graft were also evaluated with thioglycolate test and pH test respectively.Compared to native bones, no cells could be detected and residual DNA was &lt;50ng/mg dry weight. Intramedullary spaces were completely cleaned. IHC showed the preservation of intracortical vasculature with channels bounded by Collagen IV and elastin within Haversian systems. IHC also showed a significant decrease in SLA signaling. All grafts were sterile at the last decellularization step and showed no solvent residue. The control group kept in immersion baths, paired with 6 perfused radii/ulnae, showed that the perfusion is mandatory to ensure complete decellularisation.Our results prove the effectiveness of a new concept of total bone decellularisation by perfusion. These promising results could lead to a new technique of Vascularized Composite Allograft transposable to pre-clinical and clinical models.

An Evaluation of Biomarkers as Determinants of Peripheral Arterial Disease in those with Diabetes Mellitus

AbstractPeripheral arterial disease (PAD) is characterized by reduced arterial perfusion in lower limb extremities due to atherosclerosis. The disease is mostly asymptomatic with poor diagnosis and prognosis, usually co‐existing with other diseases. Its burden is rising globally, especially among diabetics; consequently increasing the risk of vascular damage, lower limb amputation, and cardiovascular disorders. Therefore, it is essential to identify biomarkers for in‐time diagnosis and efficient prognosis of diabetes‐associated PAD. In this study, several markers were evaluated that can identify PAD development in diabetics. These biomarkers include blood urea nitrogen (BUN), serum creatinine, creatine kinase‐MB (CK‐MB), prothrombin time (PT), activated partial thrombopalstin time (aPTT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), glycated hemoglobin (HbA1c), total cholesterol, triglycerides, low‐density lipoproteins (LDL), high density lipoproteins (HDL) and C reactive protein (CRP). All these markers were analyzed in blood samples using standard methods and results were interpreted by comparing them with widely accepted cut‐off values. After all experimental procedures, it was found that levels of AST (35.04 U/L), ALT (37.21 U/L), BUN (37.93 mg/dL), CK‐MB (22.01 IU/L), HbA1c (8.79 %), triglycerides (297.65 mg/dL), total cholesterol (234.59 mg/dL) and CRP (5.48 mg/L) were significantly higher in diabetic patients having PAD while slight increase was observed in coagulation profile (PT (14.27 s), aPTT (35.15 s) and INR (1.15), in diabetics plus PAD as compared to diabetics alone. However, it has been observed that levels of HDL were reduced in both diabetics (41.14 mg/dL) and diabetics plus PAD (43.54) as compared to control (healthy individuals) results (53.67) while LDL levels were increased in diabetics (117.42 mg/dL) and diabetics plus PAD (122.22) as compared to healthy individuals (102.76). Therefore, it was concluded that AST, ALT, urea, cholesterol, triglycerides, HDL, LDL, CK‐MB and CRP can serve as diagnostic and prognostic biomarkers in diabetics having PAD to improve life of patients.

Utilization of a novel 3D radiologic scoring method to define therapeutic response and surgical candidacy

PurposeNeoadjuvant therapy and surgical resection can improve the survival rate of patients who receive a diagnosis of pancreatic cancer and shows to be potentially curative. The aim of this study is to define a novel CT perfusion analytical method by observing the treatment response of pancreatic cancer patients in a neoadjuvant-treated population to determine surgical candidacy.Experimental designThis prospective study involved 22 adult patients with pancreatic ductal adenocarcinoma (PDAC). Participants received neoadjuvant therapy (paricalcitol, paclitaxel protein-bound, cisplatin, and gemcitabine) for up to 6 months. The study examined differences in density between the arterial and venous phases of CT scans using a mathematical analysis called the Marley equation. The data was used to assess treatment responses and determined whether a patient can become a surgical candidate. The consideration for surgical candidacy was defined by Dr. Rahmanuddin, termed the “R” score and graphically depicted as the “R” Clock. The R score determined the number of tumor-linked blood vessels. Any vessel associated with tumor involvement received a score of 1. Patients who received a score of 5 or less were eligible for surgery. 3D Tumor volumetric analyses were performed using GE AW 3D software to assess the treatment response associated with tumor perfusion.ResultsVisual differences in vascular involvement between baseline and final imaging were associated with a higher likelihood of proceeding to surgery. After administration of the neoadjuvant therapy, 81% of patients (18 of 22) received an R score of 5 or less, deeming all of them eligible for surgery. A total of 59% of patients (13 of 22) proceeded with the surgery. Changes in arterial and venous perfusion reflected tumor aggressiveness as defined by the Marley equation.ConclusionCT vessel perfusion using the R score and Marley Equation might be helpful in defining the surgical candidacy of PDAC patients when used in conjunction with 3D tumor volumetric quantification. The parameters defined by the R score determined higher perfusion scores as having greater vascular growth, and patients with tumor involvement of more than six vessels were deemed surgically unresectable. The Marley equation demonstrated tumor aggression via changes in arterial and venous perfusion. Additional studies are needed to further validate these methodologies and assess their clinical utility.

Twin reversed arterial perfusion sequence with a cardiac loop

Twin reversed arterial perfusion sequence with a cardiac loop

Retroauricular lymph node flap: An anatomic and surgical feasibility study.

The study investigated the anatomy of the retroauricular lymph node (LN) flap and evaluate its surgical feasibility as a new donor site for a free LN flap in lymphedema surgery. Twelve adult cadavers were examined. The course and perfusion of the anterior auricular artery (AAA) and the location and sizes of the retroauricular LNs were studied. The AAA was available in 87% and absent in 13% specimens. The AAA's origin had a mean vertical distance of 12.2 ± 6.9 mm and a mean horizontal distance of 19.1 ± 4.2 mm from the superior attachment of the ear. The mean diameter of the AAA was 0.8 ± 0.2 mm. The mean number of LN per region was 7.7 ± 2.3, with an average LN size of 4.1 ± 1.9 × 3.2 ± 1.7 mm. The LN were categorized into anterior (G1) and posterior (G2) groups, with a total of 59 and 10 LN, respectively. In a cluster analysis, three LN clusters could be detected across the anterior group (G1). The retroauricular LN flap is a delicate but feasible flap with reliable anatomy, containing a mean of 7.7 LNs.

Comparison of arterial spin labeling perfusion with dynamic susceptibility contrast perfusion in Moyamoya disease.

Moyamoya disease (MMD) leads to frequent ischemic/hemorrhagic manifestations. Our aim was to compare findings of arterial spin labeling (ASL) with dynamic susceptibility contrast (DSC) perfusion in patients of MMD. Patients diagnosed as MMD underwent magnetic resonance imaging with ASL and DSC perfusion sequences. Perfusion in bilateral anterior cerebral artery and middle cerebral artery territories at two levels (level of thalami and centrum semiovale) was graded as normal (score 1), or reduced (score 2) on DSC and ASL cerebral blood flow (CBF) maps by comparison with normal cerebellar perfusion. Time to peak (TTP) maps of DSC perfusion were also qualitatively scored as normal (score 1), or increased (score 2) similarly. Correlation between scores of ASL, CBF, DSC, CBF, and DSC, TTP maps was assessed by using Spearman's rank correlation. Among the 34 patients, we did not find any significant correlation between the ASL CBF maps and DSC CBF maps (r = -0.028, P = 0.878), mean matching index 0.39 ± 0.31, whereas significant correlation was noted between the ASL CBF maps and DSC TTP maps (r = 0.58, P = 0.0003), mean matching index 0.79 ± 0.26. ASL CBF underestimated the perfusion compared to DSC perfusion. ASL perfusion CBF maps do not match the DSC perfusion CBF maps and rather match the TTP maps of DSC perfusion. This is explained by inherent problems in estimation of CBF in these techniques because of delay in arrival of label (in ASL perfusion) or contrast bolus (in DSC perfusion) due to the presence of stenotic lesions.

Effect of short-term nutritional supplementation of green microalgae on some reproductive indicators of Anglo-Nubian crossbred goats

Background and Aim: Despite the wide spectrum of uses, one of the chief drawbacks to expanding microalgae as a food supplement in livestock is the lack of a regimen protocol with established dosage and time length of supplementation. Therefore, this study aimed to investigate the effect of short-term supplementation with increasing doses of microalgae on ovarian response in goats reared in northeast Brazil. Materials and Methods: Twenty-eight goats had their follicular waves synchronized using three injections of a prostaglandin analog at 7-day intervals. Goats were allocated to groups that received daily oral Chlorella supplementation for 7 days, respectively: 5 g, GMA5 group (n = 7), 10 g (GMA10; n = 7), and 20 g (GMA20; n = 7). The control group (GMA 0; n = 7) received a drench of water. Results: The groups showed a quadratic increase (p = 0.0156) in kidney fat thickness but there was a significant reduction in dry matter intake in the GMA20 group. The GMA20 group showed higher glucose levels and glutathione peroxidase (p &lt; 0.05). There was a decrease in plasma cholesterol (p &lt; 0.05) in the 10 and 20 g treatments. The number of total follicles increased quadratically. Follicles &lt;3 mm increased linearly (p = 0.0113) for microalgal supply. The GMA10 and GMA20 groups had the highest values (p &lt; 0.05) among the treatments. After inducing ovulation, there was a significant increase in follicles &gt;3 mm in the GMA10 group, which also showed a greater (p &lt; 0.05) area of intraovarian blood perfusion and pulsatility index of the ovarian artery. Conclusion: We conclude that for 7 days of supplementation, the administration of 10 g of microalgae appears to be the most efficient dosage for stimulating the ovarian response in tropical goats. Keywords: Doppler, follicles, goat, microalga, ovarian blood flow, ovarian response.

Effect of short-term nutritional supplementation of green microalgae on some reproductive indicators of Anglo-Nubian crossbred goats.

Despite the wide spectrum of uses, one of the chief drawbacks to expanding microalgae as a food supplement in livestock is the lack of a regimen protocol with established dosage and time length of supplementation. Therefore, this study aimed to investigate the effect of short-term supplementation with increasing doses of microalgae on ovarian response in goats reared in northeast Brazil. Twenty-eight goats had their follicular waves synchronized using three injections of a prostaglandin analog at 7-day intervals. Goats were allocated to groups that received daily oral Chlorella supplementation for 7 days, respectively: 5 g, GMA5 group (n = 7), 10 g (GMA10; n = 7), and 20 g (GMA20; n = 7). The control group (GMA 0; n = 7) received a drench of water. The groups showed a quadratic increase (p = 0.0156) in kidney fat thickness but there was a significant reduction in dry matter intake in the GMA20 group. The GMA20 group showed higher glucose levels and glutathione peroxidase (p < 0.05). There was a decrease in plasma cholesterol (p < 0.05) in the 10 and 20 g treatments. The number of total follicles increased quadratically. Follicles <3 mm increased linearly (p = 0.0113) for microalgal supply. The GMA10 and GMA20 groups had the highest values (p < 0.05) among the treatments. After inducing ovulation, there was a significant increase in follicles >3 mm in the GMA10 group, which also showed a greater (p < 0.05) area of intraovarian blood perfusion and pulsatility index of the ovarian artery. We conclude that for 7 days of supplementation, the administration of 10 g of microalgae appears to be the most efficient dosage for stimulating the ovarian response in tropical goats.

Predictive factors for improvement of symptomatic cerebral vasospasm following subarachnoid hemorrhage by selective intra-arterial administration of fasudil hydrochloride.

Symptomatic cerebral vasospasm after subarachnoid hemorrhage (SAH) is a significant cause of delayed cerebral ischemia that leads to poor outcomes. Selective intra-arterial administration of fasudil hydrochloride (IAF) has been adopted for its vasodilatory effect on spasm arteries to prevent delayed cerebral ischemia. However, its effect on clinical outcomes and predictive factors for good recovery are not fully understood. This study aimed to investigate the outcomes of selective IAF and identify predictive factors for good outcomes in patients with cerebral vasospasm after SAH. A retrospective study of 36 patients with cerebral vasospasm following SAH who underwent selective IAF at our institution between January 2014 and May 2022 was conducted. We evaluated the improvements in neurological findings before and after selective IAF. Statistical analyses were performed to determine factors associated with good outcomes. Selective IAF improved the neurological findings in 26 patients (72.2%). Pre-therapeutic absence of cerebral infarction in more than 1/3 of the spasm artery perfusion area was significantly associated with an improvement in neurological findings (p < 0.0001). Furthermore, there was a tendency for a good outcome when the age was younger (p = 0.093), and the spasm was limited to peripheral vessels (p = 0.065). Our study indicates that selective IAF has a promising effect in improving symptomatic vasospasm, except when a large cerebral infarction exists in the spasm artery perfusion area. Early consideration of selective IAF could be recommended once patients experience symptomatic cerebral vasospasm after SAH.

GLP-1 Promotes Cortical and Medullary Perfusion in the Human Kidney and Maintains Renal Oxygenation During NaCl Loading.

Background GLP-1 (glucagon-like peptide-1) receptor agonists exert beneficial long-term effects on cardiovascular and renal outcomes. In humans, the natriuretic effect of GLP-1 depends on GLP-1 receptor interaction, is accompanied by suppression of angiotensin II, and is independent of changes in renal plasma flow. In rodents, angiotensin II constricts vasa recta and lowers medullary perfusion. The current randomized, controlled, crossover study was designed to test the hypothesis that GLP-1 increases renal medullary perfusion in healthy humans. Methods and Results Healthy male participants (n=10, aged 27±4 years) ingested a fixed sodium intake for 4 days and were examined twice during a 1-hour infusion of either GLP-1 (1.5 pmol/kg per minute) or placebo together with infusion of 0.9% NaCl (750 mL/h). Interleaved measurements of renal arterial blood flow, oxygenation (R2*), and perfusion were acquired in the renal cortex and medulla during infusions, using magnetic resonance imaging. GLP-1 infusion increased medullary perfusion (32±7%, P<0.001) and cortical perfusion (13±4%, P<0.001) compared with placebo. Here, NaCl infusion decreased medullary perfusion (-5±2%, P=0.007), whereas cortical perfusion remained unchanged. R2* values increased by 3±2% (P=0.025) in the medulla and 4±1% (P=0.008) in the cortex during placebo, indicative of decreased oxygenation, but remained unchanged during GLP-1. Blood flow in the renal artery was not altered significantly by either intervention. Conclusions GLP-1 increases predominantly medullary but also cortical perfusion in the healthy human kidney and maintains renal oxygenation during NaCl loading. In perspective, suppression of angiotensin II by GLP-1 may account for the increase in regional perfusion. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04337268.

The impact of oxygen supply and erythrocytes during normothermic kidney perfusion

The influence of erythrocytes and oxygen concentration on kidneys during long-term normothermic kidney perfusion is under debate. This study compares acellular and erythrocyte-based NMP with focus on oxygen delivery to the tissue as well as the effects of high oxygenation on tissue integrity. Pig kidneys were connected to NMP for six hours. The first group (n = 6; AC500) was perfused without addition of oxygen carriers, arterial perfusate pO2 was maintained at 500 mmHg. In the second group (n = 6; RBC500) washed erythrocytes were added to the perfusate at pO2 of 500 mmHg. Third group (n = 6; RBC200) was perfused with erythrocyte containing perfusate at more physiological pO2 of 200 mmHg. Addition of RBC did not relevantly increase oxygen consumption of the kidneys during perfusion. Likewise, there were no differences in kidney functional and injury parameters between AC500 and RBC500 group. Expression of erythropoietin as indicator of tissue hypoxia was comparable in all three groups. Cell free NMP at supraphysiological oxygen partial pressure seems to be a safe alternative to erythrocyte based perfusion without adverse effect on kidney integrity and provides a less cumbersome application of NMP in clinical practice.

A magnetic resonance imaging-based computational analysis of cerebral hemodynamics in patients with carotid artery stenosis.

Management of asymptomatic carotid artery stenosis (CAS) relies on measuring the percentage of stenosis. The aim of this study was to investigate the impact of CAS on cerebral hemodynamics using magnetic resonance imaging (MRI)-informed computational fluid dynamics (CFD) and to provide novel hemodynamic metrics that may improve the understanding of stroke risk. CFD analysis was performed in two patients with similar degrees of asymptomatic high-grade CAS. Three-dimensional anatomical-based computational models of cervical and cerebral blood flow were constructed and calibrated patient-specifically using phase-contrast MRI flow and arterial spin labeling perfusion data. Differences in cerebral hemodynamics were assessed in preoperative and postoperative models. Preoperatively, patient 1 demonstrated large flow and pressure reductions in the stenosed internal carotid artery, while patient 2 demonstrated only minor reductions. Patient 1 exhibited a large amount of flow compensation between hemispheres (80.31%), whereas patient 2 exhibited only a small amount of collateral flow (20.05%). There were significant differences in the mean pressure gradient over the stenosis between patients preoperatively (26.3 vs. 1.8 mmHg). Carotid endarterectomy resulted in only minor hemodynamic changes in patient 2. MRI-informed CFD analysis of two patients with similar clinical classifications of stenosis revealed significant differences in hemodynamics which were not apparent from anatomical assessment alone. Moreover, revascularization of CAS might not always result in hemodynamic improvements. Further studies are needed to investigate the clinical impact of hemodynamic differences and how they pertain to stroke risk and clinical management.

Worsened Stroke Outcome in a Model of Preeclampsia is Associated With Poor Collateral Flow and Oxidative Stress.

Preeclampsia increases the incidence of maternal stroke, a devastating condition that is on the rise. We investigated stroke outcome in a model of experimental preeclampsia with and without treatment with clinically relevant doses of magnesium sulfate (experimental preeclampsia+MgSO4) compared to normal late-pregnant and nonpregnant rats. Transient middle cerebral artery occlusion was used to induce focal stroke for either 1.5 or 3 hours. Infarct volume and hemorrhagic transformation were determined as measures of stroke outcome. Changes in core middle cerebral artery and collateral flow were measured by dual laser Doppler. The relationship between middle cerebral artery perfusion deficit and infarction was used as a measure of ischemic tolerance. Oxidative stress and endothelial dysfunction were measured by 3-nitrotyrosine and 8-isoprostane, in brain and serum, respectively. Late-pregnant animals had robust collateral flow and greater ischemic tolerance of brain tissue, whereas experimental preeclampsia had greater infarction that was related to poor collateral flow, endothelial dysfunction, and oxidative stress. Importantly, pregnancy appeared preventative of hemorrhagic transformation as it occurred only in nonpregnant animals. MgSO4 did not provide benefit to experimental preeclampsia animals for infarction. Stroke outcome was worse in a model of preeclampsia. As preeclampsia increases the risk of future stroke and cardiovascular disease, it is worth understanding the influence of preeclampsia on the material brain and factors that might potentiate injury both during the index pregnancy and years postpartum.

Diagnostic Accuracy of Plasma Cystatin C and Renal Resistive Index for Acute Kidney Injury in Critically Ill Patients: A Prospective Observational Study.

Acute kidney injury (AKI) is a quite common problem in critically ill patients. Serum cystatin C has emerged as a marker of AKI. This study was aimed to evaluate the diagnostic ability of serum Cystatin-C and Renal Resistive Index in prediction of AKI among critically ill patients. This prospective observational study was carried out in the department of Medicine, over a period of one year. After informed consent and ethical clearance total 120 critically ill patients suffering from sepsis were enrolled, out of which 70 patients developed AKI while 50 did not develop AKI during treatment in Intensive care unit (ICU). Serum cystatin C was measured on day 1 by particle-enhanced immune nephelometric assay, Renal resistive index (RRI) calculated by ratio of the velocities of arterial perfusion throughout the cardiac phase and glomerular filtration rate was measured on days 1, 3, and 7 respectively. S. cystatin C value was significantly higher(>3times) in AKI patients (14.07±4.8 mcg/ml) as compared to those who did not develop AKI (4.28±3.27 mcg/ml) (p<0.001). After ROC analysis it was found that day1, S. cystatin C, at cut off value of ≥9.29 mcg/ml had diagnostic accuracy 90% with sensitivity 91%, specificity89% and PPV 95.5%. While RRI value on day 7, at cut-off value of ≥0.72, had diagnostic accuracy 98%, sensitivity (98.6%) and specificity (96.7%) for AKI with 98.6% PPV, 96.7% NPV. Serum cystatin C appears to be a promising bio- markers for early diagnosis of AKI in critically ill patients. Whereas, RRI although non-invasive had good diagnostic accuracy but it diagnosed AKI after few days thus diagnosis of kidney injury delayed.

Abstract WP210: Aptamer Inhibitor Of Von Willebrand Factor Induces Thrombolysis And Improves Vascular Patency Upon Immediate And Delayed Treatment Of Stroke In An In Vitro Microfluidic Model

Von Willebrand factor (VWF) is critical in arterial thrombosis. Previous studies have shown that aptamer BB-031, a VWF inhibitor, induces thrombolysis in vivo in ischemic stroke models, making it a promising stroke therapeutic. We hypothesized that BB-031 will induce thrombolysis in an ex vivo ischemic stroke model and that advanced imaging techniques will provide mechanistic information. A microfluidic model was utilized to simulate ischemic stroke and drug delivery without disturbing the occluding thrombus. Heparinized whole blood was obtained from healthy volunteers (N=10). A gravity-based constant pressure microfluidic system mimicking arterial perfusion induced occlusive thrombosis at a collagen-coated region of stenosis. After resting for 0, 3, or 6 hours to allow retraction in situ thrombi were reperfused with blood containing 1692nM (~1mg/kg) BB-031, 0.7nM alteplase (ALT), 0.7nM tenecteplase (TEN), or vehicle 500um upstream of the thrombus using a separate inlet. Platelets were labelled prior to thrombus formation and reperfusion using fluorescent anti-CD41. Thrombolysis and patency were then monitored for 2hrs via outlet mass recording and z-stacked immunofluorescent imaging. Upon immediate reperfusion, 1692nM (~1mg/kg) BB-031 increased mean mass output by 0.250±0.629g compared to 0.031±0.065g with vehicle, 0.074±0.061g with ALT, and 0.101±0.150g with 0.7nM TEN. After a 3-hour retraction period, BB-031 reperfusion mean mass output was 0.951±1.279g compared to 0.301±0.380g with vehicle, 0.412±0.681g with ALT, and 0.569±0.714g with TEN. After 6-hours resting, reperfusion mass output increased by 1.354±1.433g with BB-031, 0.368±0.538g with vehicle, 0.158±0.195g with ALT, and 0.520±0.539g with TEN. Representative z-stacked renderings of the thrombus pre and post reperfusion from a 0-hour resting period show a volumetric decrease in thrombus size of 39% with BB-031 compared to 25% and 18% reduction with vehicle and ALT respectively in a donor-matched dataset. BB-031 improves patency in a microfluidic model of biofidelic thrombolysis compared to current standards of care, which is enhanced at 3 and 6 hours post-occlusion. This may be due to VWF-dependent lysis resulting in reduced thrombus volume.