Cardiorenal Syndromes and Their Role in Water and Sodium Homeostasis

Sodium is the main osmotically active ion in the extracellular fluid and its concentration goes hand in hand with fluid volume. Under physiological conditions, homeostasis of sodium and thus amount of fluid is regulated by neural and humoral interconnection of body tissues and organs. Both heart and kidneys are crucial in maintaining volume status. Proper kidney function is necessary to excrete regulated amount of water and solutes and adequate heart function is inevitable to sustain renal perfusion pressure, oxygen supply etc. As these organs are bidirectionally interconnected, injury of one leads to dysfunction of another. This condition is known as cardiorenal syndrome. It is divided into five subtypes regarding timeframe and pathophysiology of the onset. Hemodynamic effects include congestion, decreased cardiac output, but also production of natriuretic peptides. Renal congestion and hypoperfusion leads to kidney injury and maladaptive activation of renin-angiotensin-aldosterone system and sympathetic nervous system. In cardiorenal syndromes sodium and water excretion is impaired leading to volume overload and far-reaching negative consequences, including higher morbidity and mortality of these patients. Keywords: Cardiorenal syndrome, Renocardiac syndrome, Volume overload, Sodium retention.

Clinical and radiological results of TLIF surgery with titanium-coated PEEK or uncoated PEEK cages: a prospective single-centre randomised study

BACKGROUND

A comparison of fusion rates and clinical outcomes of instrumented transforaminal interbody fusion (TLIF) between polyetheretherketone (PEEK) and titanium-coated PEEK (Ti-PEEK) cages is not well documented.

METHODS

A single-centre, prospective, randomised study included patients who underwent one-level TLIF between L3-S1 segments. Patients were randomised into one of two groups: TLIF surgery with the PEEK cage and TLIF surgery with the Ti-PEEK cage. Clinical results were measured. All patients were assessed by repeated X-rays and 3D CT scans. Cage integration was assessed using a modified Bridwell classification. The impact of obesity and smoking on fusion quality was also analysed. Patients in both groups were followed up for 2 years.

RESULTS

Altogether 87 patients were included in the study: of these 87 patients, 81 (93.1%) completed the 2-year follow-up. A significant improvement in clinical outcome was found in the two measurements scales in both groups (RM: p = 0.257, VAS: p = 0.229). There was an increase in CobbS and CobbL angle in both groups (p = 0.172 for CobbS and p = 0.403for CobbL). Bony fusion was achieved in 37 of 40 (92.5%) patients in the TiPEEK group and 35 of 41 (85.4%) in the PEEK group (p = 0.157). Cage subsided in 2 of 40 patients (5%) in the TiPEEK group and 11 of 41 (26.8%) in the PEEK group (p = 0.007). Body mass index > 30 and smoking were not predictive factors of bony fusion achievement.

CONCLUSION

There is no significant advantage of TiPEEK cages over PEEK cages in clinical outcome and fusion rate 2 years after surgery.

A large arteriovenous fistula steals a considerable part of systemic blood flow during veno-arterial extracorporeal circulation support in a porcine model

Background: Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is one of the most frequently used mechanical circulatory support devices. Distribution of extracorporeal membrane oxygenation flow depends (similarly as the cardiac output distribution) on regional vascular resistance. Arteriovenous fistulas (AVFs), used frequently as hemodialysis access, represent a low-resistant circuit which steals part of the systemic perfusion. We tested the hypothesis that the presence of a large Arteriovenous fistulas significantly changes organ perfusion during a partial and a full Veno-arterial extracorporeal membrane oxygenation support. Methods: The protocol was performed on domestic female pigs held under general anesthesia. Cannulas for Veno-arterial extracorporeal membrane oxygenation were inserted into femoral artery and vein. The Arteriovenous fistulas was created using another two high-diameter extracorporeal membrane oxygenation cannulas inserted in the contralateral femoral artery and vein. Catheters, flow probes, flow wires and other sensors were placed for continuous monitoring of haemodynamics and organ perfusion. A stepwise increase in extracorporeal membrane oxygenation flow was considered under beating heart and ventricular fibrillation (VF) with closed and opened Arteriovenous fistulas. Results: Opening of a large Arteriovenous fistulas (blood flow ranging from 1.1 to 2.2 L/min) resulted in decrease of effective systemic blood flow by 17%-30% (p < 0.01 for all steps). This led to a significant decrease of carotid artery flow (ranging from 13% to 25% after Arteriovenous fistulas opening) following VF and under partial extracorporeal membrane oxygenation support. Cerebral tissue oxygenation measured by near infrared spectroscopy also decreased significantly in all steps. These changes occurred even with maintained perfusion pressure. Changes in coronary artery flow were driven by changes in the native cardiac output. Conclusion: A large arteriovenous fistula can completely counteract Veno-arterial extracorporeal membrane oxygenation support unless maximal extracorporeal membrane oxygenation flow is applied. Cerebral blood flow and oxygenation are mainly compromised by the effect of the Arteriovenous fistulas. These effects could influence brain function in patients with Arteriovenous fistulas on Veno-arterial extracorporeal membrane oxygenation.

Comparing the hemodynamic effect of a large arteriovenous fistula during high and low cardiac output states

Background: A large arteriovenous fistula (AVF) is a low-resistant circuit that affects organ perfusion and systemic hemodynamics even in standard conditions. The extent of its' effect in critical states has not been elucidated yet. We used norepinephrine to create systemic vasoconstriction, dobutamine to create high cardiac output, and rapid right ventricle pacing as a model of acute heart failure in a porcine model of high-flow AVF circulation. Methods: The protocol was performed on nine domestic female pigs under general anesthesia. AVF was created by connecting two high-diameter ECMO cannulas inserted in the femoral artery and vein. Continuous hemodynamic monitoring was performed throughout the protocol. Three interventions were performed-moderate dose of norepinephrine (0.25 ug/kg/min), moderate dose of dobutamine (10 ug/kg/min) and rapid right ventricle pacing to simulate low cardiac output state with mean arterial pressure under 60 mmHg. Measurements were taken with opened and closed arteriovenous fistula. Results: Continuous infusion of norepinephrine with opened AVF significantly increased mean arterial pressure (+20%) and total cardiac output (CO) (+36%), but vascular resistance remained virtually unchanged. AVF flow (Qa) rise correlated with mean arterial pressure increase (+20%; R = 0.97, p = 0.0001). Effective cardiac output increased, leading to insignificant improvement in organ perfusion. Dobutamine substantially increased cardiac output with insignificant effect on AVF flow and mean arterial pressure. Carotid artery blood flow increased significantly after dobutamine infusion by approximately 30%, coronary flow velocity increased significantly only in closed AVF state. The effective cardiac output using the heart failure model leading to decrease of carotid artery flow and worsening of brain and peripheral tissue oximetry. AVF blood flow also dropped significantly and proportionally to pressure, but Qa/CO ratio did not change. Therefore, the effective cardiac output decreased. Conclusion: In abovementioned extreme hemodynamic conditions the AVF flow was always directly proportional to systemic perfusion pressure. The ratio of shunt flow to cardiac output depended on systemic vascular resistance. These experiments highlight the detrimental role of a large AVF in these critical conditions' models.

Comprehensive evaluation of microRNA as a biomarker for the diagnosis of hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Current guidelines for HCC management recommend surveillance of high-risk patients every 6 mo using ultrasonography. Serum biomarkers, like alpha-fetoprotein (AFP), protein induced by vitamin K absence/antagonist-II (PIVKA-II) and lectin-reactive AFP, show suboptimal performance for detection of HCC, which is crucial for successful resection or treatment. Thus, there is a significant need for new biomarkers to aid early diagnosis of HCC. Studies have shown that the expression level of human microRNAs (miRNAs), a small, non-coding RNA species released into the blood, can serve as an early marker for various diseases, including HCC.

AIM

To evaluate the diagnostic role of miRNAs in HCC as single markers, signatures or in combination with known protein biomarkers.

METHODS

Our prospective, multicenter, case-control study recruited 660 participants (354 controls with chronic liver disease and 306 participants with HCC) and employed a strategy of initial screening by two independent methods, real-time quantitative PCR (n = 60) and next-generation sequencing (n = 100), to assess a large number of miRNAs. The results from the next-generation sequencing and real-time quantitative PCR screening approaches were then combined to select 26 miRNAs (including two putative novel miRNAs). Those miRNAs were analyzed for their diagnostic potential as single markers or in combination with other miRNAs or established protein biomarkers AFP and PIVKA-II via real-time quantitative PCR in training (n = 200) and validation cohorts (n = 300).

RESULTS

We identified 26 miRNAs that differentiated chronic liver disease controls from (early) HCC via two independent discovery approaches. Three miRNAs, miR-21-5p (miR-21), miR-320a and miR-186-5p, were selected by both methods. In the training cohort, only miR-21, miR-320d and miR-423 could significantly distinguish (Q < 0.05) between the HCC and chronic liver disease control groups. In the multivariate setting, miR-21 with PIVKA-II was selected as the best combination, resulting in an area under the curve of 0.87 for diagnosis and area under the curve of 0.74 for early diagnosis of HCC. In the validation cohort, only miR-21 and miR-423 could be confirmed as potential HCC biomarkers. A combination of miRNAs did not perform better than any single miRNA. Improvement of PIVKA-II performance through combination with miRNAs could not be confirmed in the validation panel. Two putative miRs, put-miR-6 and put-miR-99, were tested in the training and validation panels, but their expression could only be detected in very few samples and at a low level (cycle threshold between 31.24 and 34.97).

CONCLUSION

miRNAs alone or as a signature in combination with protein biomarkers AFP and PIVKA-II do not improve the diagnostic performance of the protein biomarkers.

Translation of Prognostic and Pharmacodynamic Biomarkers from Trial to Non-trial Patients with Metastatic Castration-resistant Prostate Cancer Treated with Docetaxel

AIMS

We conducted a pooled analysis of four randomised controlled trials and a non-trial retrospective dataset to study the changes in serum prostate-specific antigen (PSA) concentrations during treatment and its impact on survival in men treated with docetaxel for metastatic castration-resistant prostate cancer. We also compared the outcomes and pre-treatment prognostic factors between trial and non-trial patients.

MATERIALS AND METHODS

Data were obtained from four randomised controlled trials and a non-trial cohort from a tertiary cancer centre. The PSA kinetics covariates chosen were absolute value (PSAT), best percentage change (BPCH) and tumour growth rate (K). The association between the covariates collected and overall survival was assessed within a Cox proportional hazards model. How well a covariate captured the difference between trial and non-trial patients was assessed by reporting on models with or without trial status as a covariate.

RESULTS

We reviewed individual datasets of 2282 patients. The median overall survival for trial patients was 20.4 (95% confidence interval 19.6-22.2) months and for the non-trial cohort was 12.4 (10.7-14.7) months (P < 0.001). Of the pre-treatment factors, we found that only lactate dehydrogenase fully captured the difference in prognosis between the trial and non-trial cohorts. All PSA kinetic metrics appeared to be prognostic in both the trial and non-trial patients. However, the effect size was reduced in non-trial versus trial patients (interaction P < 0.001). Of the time-dependent covariates, we found that BPCH best captured the difference between trial and non-trial patient prognosis.

CONCLUSIONS

The analysis presented here highlights how data from open-source trial databases can be combined with emerging clinical practice databases to assess differences between trial versus non-trial patients for particular treatments. These results highlight the importance of developing prognostic models using both pre-treatment and time-dependent biomarkers of new treatments.

1679 An Unusual Case of Hypoplastic Internal Carotid Artery with Segmental Aplasia of The Anterior Cerebral Artery: A Case Report and Systematic Literature Review

Aim

Hypoplasia of the internal carotid artery (ICA) is a rare morphological variant with potential implications in disease and clinical decision-making. We describe an unusual case of ICA hypoplasia in a 50-year-old female who presented with an acute episode of vertigo. CT angiogram showed an unusually short common carotid artery (CCA) on the right side, hypoplasia of the right ICA, and agenesis of the A1 segment of the right anterior cerebral artery (ACA). We provide a short review of the available literature.

Method

The literature review was performed according to PRISMA guidelines. Three databases (Pubmed, Web of Science, and Ovid) were searched using the terms “ICA” and “Hypoplasia”. Case reports published in English in the last 10 years were considered eligible for inclusion. Reports of acquired ICA hypoplasia or ICA agenesis were excluded.

Results

Our systematic literature search revealed that 19 cases of congenital ICA hypoplasia have been reported in the last 10 years. Of these, 14 were unilateral hypoplasia, including nine cases in which the anomaly was on the left, and five cases in which the anomaly was on the right. Two cases had additional aplasias; one with aplasia of the ACOM and another with aplasia of segment C6 of the ICA.

Conclusions

We conclude that ICA hypoplasia remains a rare anomaly, despite the increasing incidence due to the availability of imaging technology. Clinicians should be aware of these variations, as they are frequently associated with haemodynamic changes, aneurysms, and fenestrations. Such variations have important implications for planning angiographic and surgical approaches.

Measuring COVID-19 anxiety among russians: Examining the psychometric properties of russian translations of the covid-anxiety scale and the fear of coronavirus-19 scale

Introduction

Both the COVID-Anxiety Scale and the Fear of Coronavirus-19 Scale have been recently developed to facilitate research on COVID-19 anxiety.

Objectives

To examine the psychometric properties of Russian translations of the COVID-Anxiety Scale and the Fear of Coronavirus-19 Scale.

Methods

In order to examine the psychometric properties of Russian translations of the COVID-Anxiety Scale and the Fear of Coronavirus-19 Scale, a total of 341 Russian adults completed both measures.

Results

First, a high level of COVID-19 anxiety was found in the sample. Second, confirmatory factor analysis demonstrated that the Russian translations of both the COVID-Anxiety Scale and the Fear of Coronavirus-19 Scale had satisfactory psychometric properties, with both scales having a hypothesised one-factor structure. Third, a significant positive association was found between both the COVID anxiety scales. Fourth, higher COVID anxiety scores were associated with being female, and being older.

Conclusions

These findings provide initial evidence for the satisfactory properties of the Russian translations of the COVID-Anxiety Scale and the Fear of Coronavirus-19 Scale. Further research is suggested that examines the prevalence and psychological correlates of COVID-19 anxiety.

Ultrasound evaluation of dialysis access-related distal ischaemia

Dialysis access-related distal ischaemia is a rare yet potentially rather risky complication of haemodialysis angioaccess. Timely diagnosis is crucial to target both the goals of the access team: first of all to preserve the function of the hand ideally along with angioaccess patency. Unfortunately for some patients, urgent access ligation and central vein catheter insertion would be needed to save the hand. After a first clinical examination to determine the diagnostic suspicion, the ultrasound evaluation would provide nearly all the needed information to confirm the diagnosis and to determine the most appropriate procedure to rescue the patient from distal ischaemia. In some cases, photoplethysmography would help in the differential diagnosis of other non-ischaemic causes of similar signs and symptoms. Angiography would complete the preoperative evaluation for some.Dialysis access-related distal ischaemia would be briefly reviewed, and a deep description of the ultrasound examination tools and findings would be provided for a tailored therapeutic approach.

Review of the structural and functional brain changes associated with chronic kidney disease

Chronic kidney disease (CKD) leads to profound metabolic and hemodynamic changes, which damage other organs, such as heart and brain. The brain abnormalities and cognitive deficit progress with the severity of the CKD and are mostly expressed among hemodialysis patients. They have great socio-economic impact. In this review, we present the current knowledge of involved mechanisms.

Endocrine dysfunction in psychology during social distancing measures

OBJECTIVES

To determine the psychological impact of the social distancing measures in place due to the coronavirus pandemic.

METHODS

We conducted a cross-sectional study on the Pakistani population. Informed consent was taken from all the participants. The data was collected through an online questionnaire. Cronbach's alpha was used to assess the internal consistency of the questionnaire, and it was found to be 0.80. The data obtained was analyzed on IBM's statistical package for the social sciences (SPSS) version 26.

RESULTS

Out of 706 participants, 489 (69.26 %) were males and 217 (30.74 %) were females. The mean age of the participants was 35.24 ± 12.08 years. The majority of the participants were from Punjab (66.00 %).The mean time since quarantine measures had been established was 10.35 ± 5.09 days. The mean total score was 9.08 ± 2.38 points. A majority of the participants (25.64 %) were daily wage workers. t-test was significant when the time of quarantine was compared to the psychological impact. Significant results were also found when gender was compared to the impact.

CONCLUSIONS

Social distancing measures have an impact on psychology and endocrinology of people in general. The impact can take the shape of long-lasting consequences (Tab. 3, Ref. 19).

P1359 Left ventricle hypertrophy and diastolic dysfunction in haemodialysis patients after surgical reduction of arteriovenous fistula blood flow

Funding Acknowledgements

Grant of the Grant Agency of Charles University and grant of the Czech Health Research council

Introduction

Over 50% of patients treated by chronic haemodialysis programme die of cardiovascular diseases. Changes of heart structure and function can be detected by echocardiography. The most frequent changes are left ventricle hypertrophy (LVH) and its diastolic dysfunction. One of the considered contributing mechanisms is the hyperkinetic circulation.

Purpose

The aim of this study was to analyse the effect of high flow arteriovenous fistula (AVF) on eft ventricular hypertrophy and diastolic function.

Materials and methods

We included 30 patients with a high-flow arteriovenous fistula into the study, indicated for AVF blood flow reduction because of heart failure or hand ischemia. All the patients underwent echocardiographic examination and ultrasonographic measurement of AVF blood flow before and 6 weeks after the surgery.

Results

The AVF banding led to significant reduction of Qa (from 2977 ± 1408 to 1295 ± 610 mL/min; p ˂ 10-6, accompanied by significant decrease of cardiac index (from 4.34 ± 1.09 to 3.56 ± 0.90 L/min.m2). These findings were accompanied by significant reduction of left ventricle mass index (from 125 ± 31 to 116 ± 32 g/m2; p = 0.04) and by improvement of diastolic dysfunction grade (from 1.66 ± 0.67 to 1.14 ± 0.95; p = 0.03). The maximum velocity of tricuspid regurgitation decreased (from 3.1 ± 0.4 to 2.7 ± 0.5), and so did the left atrium volume index (from 47 ± 14 to 42 ± 15 mL/m2; p = 0.01).

Conclusions

LVH and diastolic dysfunction are frequent in haemodialysis patients; hyperkinetic circulation caused by high-flow arteriovenous fistula is one of the significant contributing mechanisms. Surgical reduction of AVF blood flow improved diastolic function of the left ventricle and reduced the hypertrophy in our patient population. AVF flow volume should be always considered during cardiological examination of haemodialysis patients.

Factors responsible for cerebral hypoxia in hemodialysis population

Brain tissue oxygenation (rSO(2)) measured by near-infrared spectroscopy (NIRS) is lower in hemodialysis patients than in the healthy population and is associated with cognitive dysfunction. The involved mechanisms are not known. We conducted this study to identify the factors that influence the rSO2 values in end-stage renal disease (ESRD) patients and to describe rSO2 changes during hemodialysis. We included a cohort of ESRD patients hemodialyzed in our institution. We recorded rSO2 using INVOS 5100C oximetry system (Medtronic, Essex, U.K.) and analyzed changes in basic laboratory values and hemodynamic fluctuations. Baseline rSO2 was lower in patients with heart failure (45.2±8.3 % vs. 54.1±7.8 %, p=0.006) and was significantly linked to higher red cell distribution width (RDW) (r=-0.53, p?0.001) and higher BNP level (r=-0.45, p=0.01). The rSO(2) value decreased in first 15 min of hemodialysis, this decrease correlated with drop in white blood count during the same period (r=0.43, p=0.02 in 10 min, r=0.43, p=0.02 in 20 min). Lower rSO(2) values in patients with heart failure and higher RDW suggest that hemodynamic instability combined with vascular changes probably leads to worse cerebral oxygenation in these patients. Decrease of rSO(2) in 15th minute of hemodialysis accompanied with a significant drop in leukocyte count could be explained by complement activation.

GLP-1, a powerful physiological incretin: an update

Food intake, especially carbohydrates, release incretin, which is an endocrine transmitter. Among the various endocrine modulators, Glucagon-like peptide 1 (GLP-1) is more effective in stimulating the release of insulin and more powerful regulator of physiological functions. Mainly (GLP-1) receptors are expressed in lungs, α and β cells of pancreatic islets and the nervous system. Peripheral tissues, gastrointestinal tract and extra pancreatic tissues i.e., vascular smooth muscle, kidney and heart, also contain high affinity receptors for GLP-1. The aim of this systematic review was to gather the available published evidence of the functions performed by GLP-1 through the activation of its receptor in various organs. This review suggest that GLP-1 receptor signaling helps prevent beta cell apoptosis and conserve function and morphology of human islet. The effect of GLP-1 signaling in weight loss in diabetic patients was proved by previous studies. The long term use of GLP-1 receptor agonists reduces cardiovascular and renal complications in diabetic patients. Significant evidence was found in previous literature for its effect on pancreatic secretions. The secretions of many enzymes and hormones, such as trypsin, lipase and glucagon, inhibited significantly while the increase in levels of insulin and somatostatin was reported in many studies. GLP-1 has a prominent role in cardiac functioning and increases the heart rate considerably. Based on the vast impact of GLP-1 on physiological functions, many GLP-1 receptor agonists can be made that can increase the healthy life span.

Understanding the Dialysis access Steal Syndrome. A Review of the Etiologies, Diagnosis, Prevention and Treatment Strategies

Distal hypoperfusion ischemic syndrome (DHIS), commonly referred to as hand ischemia or “steal” after dialysis access placement, occurs in 5–10% of cases when the brachial artery is used, or 10 times that of wrist arteriovenous fistulas (AVFs) using the radial artery. It is typically seen in elderly women with diabetes, and may carry severe morbidity including tissue or limb loss if not recognized and treated. Three distinct etiologies include (1) blood flow restriction to the hand from arterial occlusive disease either proximal or distal to the AV access anastomosis, (2) excess blood flow through the AV fistula conduit (true steal), and (3) lack of vascular (arterial) adaptation or collateral flow reserve (ie atherosclerosis) to the increased flow demand from the AV conduit. These three causes of steal may occur alone or in concert. The diagnosis of steal is based on an accurate history and physical examination and confirmed with tests including an arteriogram, duplex Doppler ultrasound (DDU) evaluation with finger pressures and waveform analysis. Treatment of steal includes observation of developing symptoms in mild cases. Balloon angioplasty is the appropriate intervention for an arterial stenosis. At least three distinct surgical corrective procedures exist to counteract the pathophysiology of steal. The ultimate treatment strategy depends on severity of symptoms, the extent of patient co-morbidity, and the local dialysis access technical team support and skills available.

Amperometric determination of serum total cholesterol with nanoparticles of cholesterol esterase and cholesterol oxidase

We describe the preparation of glutaraldehyde cross-linked and functionalized cholesterol esterase nanoparticles (ChENPs) and cholesterol oxidase nanoparticles (ChOxNPs) aggregates and their co-immobilization onto Au electrode for improved amperometric determination of serum total cholesterol. Transmission electron microscope (TEM) images of ChENPs and ChOxNPs showed their spherical shape and average size of 35.40 and 56.97 nm, respectively. Scanning electron microscope (SEM) studies of Au electrode confirmed the co-immobilization of enzyme nanoparticles (ENPs). The biosensor exhibited optimal response at pH 5.5 and 40°C within 5 s when polarized at +0.25 V versus Ag/AgCl. The working/linear range of the biosensor was 10-700 mg/dl for cholesterol. The sensor showed high sensitivity and measured total cholesterol as low as 0.1 mg/dl. The biosensor was evaluated and employed for total cholesterol determination in sera of apparently healthy and diseased persons. The analytical recovery of added cholesterol was 90%, whereas the within-batch and between-batch coefficients of variation (CVs) were less than 2% and less than 3%. There was a good correlation (r = 0.99) between serum cholesterol values as measured by the standard enzymic colorimetric method and the current method. The initial activity of ENPs/working electrode was reduced by 50% during its regular use (200 times) over a period of 60 days when stored dry at 4°C.

The Importance of Prostate-specific Antigen (PSA) Nadir and Early Identification of PSA Relapse after 10 Years of Prostate Iodine 125 Seed Brachytherapy in Edinburgh

AIMS

To analyse our 5 and 10 year prostate brachytherapy outcome data and to assess the impact of PSA nadir on relapse free survival and whether an alternative definition of PSA relapse could detect men destined to fail by the Phoenix definition at an earlier time point.

MATERIALS AND METHODS

474 men were treated over a 10 year period between 20012 and 2011 and divided into 2 five year cohorts for the purpose of the analysis.

RESULTS

The risk of relapse is strongly predicted by post treat prostate-specific antigen (PSA) nadir. After 3 years post-treatment, PSA nadir plus 0.4 ng/ml identified men at risk of relapse 17 months earlier than the Phoenix definition.

CONCLUSION

The Phoenix definition of nadir plus 2.0 ng/ml does not allow the early identification of men destined to relapse. The initiation of salavage therapy at the earliest opportunity could potentially affect subsequent survival and an outline randomised controlled trial proposal is presented.

Endotelial activation and flow-mediated vasodilation in young patients with breast cancer

Endothelial activation and dysfunction may play a significant role in the progression of breast cancer. In our study we examined markers of endothelial activation (soluble ICAM-1, P-selectin, E-selectin) in 98 young patients with breast cancer (< 40 years). In 50 of them (and 20 age-matched controls) we also measured flow mediated vasodilation. Patients with breast cancer had significantly higher serum levels of soluble E-selectin, P-selectin and ICAM-1, P-selectin was higher in patients with larger tumors, node involvement and seemed to be apredictor of poor outcome. We were unable to find significant difference in the parameters of flow mediated vasodilation between patients with breast cancer and healthy subjects, although both peak blood flow (PBF) and flow mediated vasodilation (FMD) seemed to be skewed compared to healthy subjects toward mean and lower levels. Cluster analysis enabled us to distinguish several larger groups of patients with different degree of endothelial activation and function and different outcome. Group of patients with high E-selectin, high ICAM-1 (higher endothelial activation) and low VEGF (putative endothelial damage) had more frequently negative estrogen receptors and had worse outcome compared to the group of patients with lower E-selectin, lower ICAM-1 and mostly positive estrogen receptors. Further studies of larger groups of patients should help to identify the panel of endothelial markers which could help in predicting the outcome of young patients with breast cancer.

A megavoltage scatter correction technique for cone-beam CT images acquired during VMAT delivery

Kilovoltage cone-beam CT (kV CBCT) can be acquired during the delivery of volumetric modulated arc therapy (VMAT), in order to obtain an image of the patient during treatment. However, the quality of such CBCTs is degraded by megavoltage (MV) scatter from the treatment beam onto the imaging panel. The objective of this paper is to introduce a novel MV scatter correction method for simultaneous CBCT during VMAT, and to investigate its effectiveness when compared to other techniques. The correction requires the acquisition of a separate set of images taken during VMAT delivery, while the kV beam is off. These images--which contain only the MV scatter contribution on the imaging panel--are then used to correct the corresponding kV/MV projections. To test this method, CBCTs were taken of an image quality phantom during VMAT delivery and measurements of contrast to noise ratio were made. Additionally, the correction was applied to the datasets of three VMAT prostate patients, who also received simultaneous CBCTs. The clinical image quality was assessed using a validated scoring system, comparing standard CBCTs to the uncorrected simultaneous CBCTs and a variety of correction methods. Results show that the correction is able to recover some of the low and high-contrast signal to noise ratio lost due to MV scatter. From the patient study, the corrected CBCT scored significantly higher than the uncorrected images in terms of the ability to identify the boundary between the prostate and surrounding soft tissue. In summary, a simple MV scatter correction method has been developed and, using both phantom and patient data, is shown to improve the image quality of simultaneous CBCTs taken during VMAT delivery.