Role of multiple- and single-pregnancy complications with incident cardiovascular diseases: a nationwide data linkage study in Wales

Background

Prior evidence has suggested that pregnancy complications are associated with a higher risk of cardiovascular disease in women. However, associations between coexisting multiple pregnancy complications and incident cardiovascular disease remains unclear.

Purpose

To examine the risk of ischemic heart disease (IHD), stroke, atrial fibrillation or heart failure among women after their first pregnancy with a history of multiple pregnancy complications and women with a history of single-pregnancy complications, compared to women without pregnancy complications.

Methods

This retrospective cohort included women aged 16–45 years who had their first pregnancy between 2000 and 2018 in Wales using the Secure Anonymised Information Linkage (SAIL) Databank. Data were extracted from various sources such as Office for National Statistics (ONS) birth and death extracts, hospital admission, outpatient, emergency department and General Practice data sources, and pregnancy related data such as maternal indicators and national community child health. Cox proportional hazard regression was used to evaluate the association between multiple or specific single pregnancy complications and incidence of cardiovascular disease.

Results

A total of 298,515 women were included in the study, of which 64,794 (21.7%) women experienced a single pregnancy complication, and 10,038 (3.38%) women experienced more than one complication during their first pregnancy. During the a median of 9.7 years of follow-up, 2,484 women developed incident cardiovascular disease. IHD had the highest incidence rate among women with multiple pregnancy complications at 9.06 (7.36–11.15) per 10,000 person-years, compared to 4.24 (3.77–4.78) among women with a single pregnancy complication and 2.40 (2.20–2.61) among women without any pregnancy complications. After adjusting for potential confounding factors, compared to no previous pregnancy complications, a history of multiple pregnancy complications was associated with a higher risk of heart failure [hazard ratio (HR) 3.18 (95% confidence interval (CI) 2.34–4.32)], IHD [HR 2.88 (95% CI 2.27–3.67)], stroke [HR 2.03 (95% CI 1.55–2.65)] and atrial fibrillation [HR 1.80 (95% CI 1.20–2.72)]. There was also a consistent trend for a higher risk of all outcomes in women with a history of single-pregnancy complications compared to women without complications during the first pregnancy (Figure 1).

Conclusion

This population-scale study used anonymised individual-level linked data from multiple routinely collected data sources. In almost 300,000 women with a previous pregnancy, multiple pregnancy complications were associated with a higher risk of incident cardiovascular disease, including heart failure, ischaemic heart disease, stroke and atrial fibrillation. Women who experience multiple pregnancy complications may benefit from targeted intervention strategies to reduce their risk of incident cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Saudi Arabia governmental PhD studentship

Associations between pregnancy complications and incident cardiovascular disease: a nationwide data linkage study in Wales

Background

Previous studies have associated pregnancy complications with a higher risk of cardiovascular disease. However, previous studies have not sufficiently evaluated the impact of broad range of pregnancy complications or common cardiovascular conditions individually. Furthermore, most previous studies have relied on data from hospital admission records only, which may not have adequately accounted for conditions that may not result in an inpatient hospital admission, such as atrial fibrillation.

Purpose

To examine the risk of ischemic heart disease (IHD), stroke, atrial fibrillation or heart failure among women after their first pregnancy with a history of pregnancy complications compared to women without pregnancy complications in a large nationwide study using linked routinely collected data.

Methods

A retrospective cohort study was conducted using the Secure Anonymised Information Linkage (SAIL) Databank and included women aged 16–45 years who had their first pregnancy between 2000 and 2018 in Wales. Data were extracted from various sources such as Office for National Statistics (ONS) birth and death extracts, hospital admission, outpatient, emergency department and General Practice data sources, and pregnancy related data such as maternal indicators and national community child health. Survival analyses were conducted using Cox proportional hazard regression models adjusted for hypertension, diabetes, hyperlipidaemia, congenital and valvular heart diseases, multifetal pregnancy ethnicity, maternal age, calendar year of first birth and index of multiple deprivation.

Results

A total of 298,515 women were included in the study, of which 74,832 (25.1%) had a history of any pregnancy complication during their first pregnancy. During a median of 9.7 years follow-up time, 2,484 women developed at least one cardiovascular condition. Among women with a history of pregnancy complication in their first pregnancy, IHD had the highest incidence rate at 4.94 (95% confidence interval (CI) 4.44–5.49) per 10,000 person-years, and atrial fibrillation was the lowest at 1.92 (95% CI 1.62–2.28). The history of any pregnancy complication during the first pregnancy was associated with a higher risk of all cardiovascular conditions examined, including heart failure [hazard ratio (HR) 1.93 95% CI 1.61–2.31)], IHD [HR 1.82 (95% CI 1.58–2.10)], stroke [HR 1.39 (95% CI 1.20–1.61)] and atrial fibrillation [HR 1.33 (95% CI 1.08–1.65) (Figure 1).

Conclusion

This population-scale study used anonymised individual-level linked data from multiple routinely collected data sources. A history of pregnancy complications during first pregnancy was associated with a higher risk of incident cardiovascular conditions, including heart failure, ischaemic heart disease, stroke and atrial fibrillation. Applying primary preventive measures and risk assessments for cardiovascular disease after the first pregnancy may mitigate the higher risk among these women.

Funding Acknowledgement

Type of funding sources: Other.

Factors associated with prescription of oral anticoagulation for atrial fibrillation in older people living in care homes in Wales: a routine data linkage study 2003–2018

Background

Prescription of oral anticoagulants (OAC) is paramount for stroke prevention in people with atrial fibrillation (AF), but treatment decisions in older care home residents are complicated by frailty, multi-morbidity and heightened stroke and bleeding risk. There is a paucity of data on factors influencing the decision to prescribe OAC in this high-risk population who are under-represented in research studies.

Purpose

To explore the factors associated with OAC prescription for care home residents aged ≥65 years with AF.

Methods

Nationwide retrospective cohort study of people aged ≥65 years entering a care home in Wales between 1 January 2003 and 31 December 2018, using anonymised individual-level electronic health record and administrative data sources available within the Secure Anonymised Information Linkage Databank. Unadjusted and adjusted logistic regression models were used to explore the association between resident characteristics and OAC prescription or non-prescription.

Results

Between 2003 and 2018, 14,493 people with AF aged ≥65 years became new residents in care homes in Wales and 7,057 (48.7%) were prescribed OAC (32.7% in 2003 compared to 72.7% in 2018), Figure 1. Increasing age and prescription of antiplatelet therapy were associated with lower odds of OAC prescription (adjusted odds ratio [aOR] 0.96 per one year age increase [95% confidence interval, 0.95 to 0.96] and aOR 0.91 [0.84 to 0.98], respectively). Conversely, prior venous thromboembolism (aOR 4.06 [3.17 to 5.20]), advancing frailty (mild: aOR 4.61 [3.95 to 5.38]; moderate: aOR 6.69 [5.74 to 7.80]; severe: aOR 8.42 [7.16 to 9.90]) and year of care home entry in the post-non-vitamin K antagonist oral anticoagulant (NOAC) era from 2011 onwards (aOR 1.91 [1.76 to 2.06]) were associated with higher odds of OAC prescription, Figure 2.

Conclusions

The proportion of care home residents prescribed OAC therapy has increased over time with the introduction of NOACs in 2011, but OAC prescription rates are still sub-optimal. Although there is an expected rise in OAC prescribing for increasingly frail people, further work is needed to investigate the interaction with deprivation and other socio-economic and demographic factors to assess potential inequalities in prescribing across these groups. Targeted educational tools for clinicians are needed to address barriers to OAC prescription for AF, such as older age and separate indications for antiplatelet therapy.

Funding Acknowledgement

Type of funding sources: None.

Prevalence and outcomes of atrial fibrillation in older people living in care homes in Wales: a routine data linkage study 2003–2018

Background

Older care home residents are a high-risk group of people with atrial fibrillation (AF) who are under-represented in clinical trials. Improved understanding of AF epidemiology and management in this population is paramount for health and social care organisations to strategically plan services.

Purpose

To determine the trends in AF prevalence and compare adverse health outcomes in older care home residents aged ≥65 years with AF compared to those without AF.

Methods

Retrospective cohort study of people entering a care home between 2003–2018 using nationwide, population-scale anonymised health and administrative data, provisioned from the Secure Anonymised Information Linkage (1 January 2000–31st December 2018). Direct standardisation was used to calculate AF prevalence by year of care entry (2010–2018). Cox regression analyses were used to estimate the risk of adverse health outcomes.

Results

Between 2003 and 2018, 86,602 people aged ≥65 years became new residents in care homes in Wales. Residents with AF (n=14,493) had a significantly higher risk (adjusted hazard ratio [aHR], 95% confidence interval [CI]) of cardiovascular (aHR 1.27 [1.17 to 1.37], p<0.001) and all-cause mortality (aHR 1.14 [1.11 to 1.17], p<0.001), Figure 1. The risk (sub-distribution hazard ratio [sHR], 95% CI) of ischaemic stroke (adjusted sHR 1.55 [1.36 to 1.76], p<0.001) and cardiovascular hospitalisation (adjusted sHR 1.28 [1.22 to 1.34], p<0.001) was also higher in residents with AF, even when mortality was considered a competing event, Figure 1. There was no significant change in age- and sex-standardised prevalence of AF between 2010 and 2018, 16.79% (95% CI 15.85 to 17.94) and 17.02% (95% CI 16.05 to 17.98), respectively (absolute change 2010–2018: 0.06% [95% CI: −1.38 to 1.50], p=0.93), Figure 2.

Conclusions

This study demonstrates unique data on the epidemiology of AF and associated outcomes in older care home residents. Whilst the prevalence of AF remained stable between 2010–2018, residents with AF had significantly higher risk of adverse health events. Treatment of AF in accordance with guidelines is critical in this population to optimise management and reduce adverse health outcomes.

Funding Acknowledgement

Type of funding sources: None.

Healthcare contacts with self-harm during COVID-19: An e-cohort whole-population-based study using individual-level linked routine electronic health records in Wales, UK, 2016-March 2021

INTRODUCTION

Reduced rates of help seeking by those who self-harmed during the COVID-19 pandemic have been reported.

OBJECTIVES

To understand changes in healthcare service contacts for self-harm during the COVID-19 pandemic across primary, emergency and secondary care.

METHODS

This retrospective cohort study used routine electronic healthcare data for Wales, United Kingdom, from 2016 to March 14, 2021. Population-based data from primary care, emergency departments and hospital admissions were linked at individual-level. All Welsh residents aged ≥10 years over the study period were included in the study. Primary, emergency and secondary care contacts with self-harm at any time between 2016 and March 14, 2021 were identified. Outcomes were counts, incidence, prevalence and proportion of self-harm contacts relative to all contacts in each and all settings, as well as the proportion of people contacting one or more settings with self-harm. Weekly trends were modelled using generalised estimated equations, with differences between 2020 (to March 2021) and comparison years 2016-2018 (to March 2017-2019) quantified using difference in differences, from which mean rate of odds ratios (μROR) across years was reported.

RESULTS

The study included 3,552,210 individuals over the study period. Self-harm contacts reduced across services in March and December 2020 compared to previous years. Primary care contacts with self-harm reduced disproportionately compared to non-self-harm contacts (μROR = 0.7, p<0.05), while their proportion increased in emergency departments during April 2020 (μROR = 1.3, p<0.05 in 2/3 comparison years) and hospital admissions during April-May 2020 (μROR = 1.2, p<0.05 in 2/3 comparison years). Despite this, those who self-harmed in April 2020 were more likely to be seen in primary care than other settings compared to previous years (μROR = 1.2, p<0.05). A lower proportion of those with self-harm contacts in emergency departments were subsequently admitted to hospital in December 2020 compared to previous years (μROR = 0.5, p<0.05).

CONCLUSIONS

These findings suggest that those who self-harmed during the COVID-19 pandemic may have been less likely to seek help, and those who did so faced more stringent criteria for admission. Communications encouraging those who self-harm to seek help during pandemics may be beneficial. However, this needs to be supported by maintained provision of mental health services.

Investigating the association between COVID-19 vaccination and care home outbreak frequency and duration

OBJECTIVES

At the end of 2020, many countries commenced a vaccination programme against SARS-CoV-2. Public health authorities aim to prevent and interrupt outbreaks of infectious disease in social care settings. We aimed to investigate the association between the introduction of the vaccination programme and the frequency and duration of COVID-19 outbreaks in Northern Ireland (NI).

STUDY DESIGN

We undertook an ecological study using routinely available national data.

METHODS

We used Poisson regression to measure the relationship between the number of RT-PCR confirmed COVID-19 outbreaks in care homes, and as a measure of community COVID-19 prevalence, the Office for National Statistics COVID-19 Infection Survey estimated the number of people testing positive for COVID-19 in NI. We estimated the change in this relationship and estimated the expected number of care home outbreaks in the absence of the vaccination programme. A Cox proportional hazards model estimated the hazard ratio of a confirmed COVID-19 care home outbreak closure.

RESULTS

Care home outbreaks reduced by two-thirds compared to expected following the introduction of the vaccination programme, from a projected 1625 COVID-19 outbreaks (95% prediction interval 1553-1694) between 7 December 2020 and 28 October 2021 to an observed 501. We estimated an adjusted hazard ratio of 2.53 of the outbreak closure assuming a 21-day lag for immunity.

CONCLUSIONS

These findings describe the association of the vaccination with a reduction in outbreak frequency and duration across NI care homes. This indicates probable reduced harm and disruption from COVID-19 in social care settings following vaccination. Future research using individual level data from care home residents will be needed to investigate the effectiveness of the vaccines and the duration of their effects.

First-dose ChAdOx1 and BNT162b2 COVID-19 vaccines and thrombocytopenic, thromboembolic and hemorrhagic events in Scotland

Reports of ChAdOx1 vaccine-associated thrombocytopenia and vascular adverse events have led to some countries restricting its use. Using a national prospective cohort, we estimated associations between exposure to first-dose ChAdOx1 or BNT162b2 vaccination and hematological and vascular adverse events using a nested incident-matched case-control study and a confirmatory self-controlled case series (SCCS) analysis. An association was found between ChAdOx1 vaccination and idiopathic thrombocytopenic purpura (ITP) (0-27 d after vaccination; adjusted rate ratio (aRR) = 5.77, 95% confidence interval (CI), 2.41-13.83), with an estimated incidence of 1.13 (0.62-1.63) cases per 100,000 doses. An SCCS analysis confirmed that this was unlikely due to bias (RR = 1.98 (1.29-3.02)). There was also an increased risk for arterial thromboembolic events (aRR = 1.22, 1.12-1.34) 0-27 d after vaccination, with an SCCS RR of 0.97 (0.93-1.02). For hemorrhagic events 0-27 d after vaccination, the aRR was 1.48 (1.12-1.96), with an SCCS RR of 0.95 (0.82-1.11). A first dose of ChAdOx1 was found to be associated with small increased risks of ITP, with suggestive evidence of an increased risk of arterial thromboembolic and hemorrhagic events. The attenuation of effect found in the SCCS analysis means that there is the potential for overestimation of the reported results, which might indicate the presence of some residual confounding or confounding by indication. Public health authorities should inform their jurisdictions of these relatively small increased risks associated with ChAdOx1. No positive associations were seen between BNT162b2 and thrombocytopenic, thromboembolic and hemorrhagic events.

Longitudinal study of adherence to anticoagulation guidelines in patients with atrial fibrillation

Introduction

Anticoagulation (AC) reduces the risk of stroke and systemic embolism (SSE) in patients with Atrial Fibrillation (AF). However, the association between changes in AF prevalence, risk factors for SSE, uptake of AC and incidence of SSE has not been documented specifically in these patients within a national population.

Purpose

Identifying antithrombotic prescribing and evaluating associations between changes in AF prevalence, SSE risk factors (CHA2DS2-VASC score) and uptake of AC. Evaluating relationships between changes in proportion of AF patients treated with AC and SSE rate at a population level. Developing a modelling tool which estimates rates of SSE (past and future) based on these factors, which can be used to drive improvements in health care.

Method

AF patients were identified in the population of Wales (SAIL databank) between 2012–2018. Temporal trends of AF, CHA2DS2-VASC scores, anti-thrombotic prescriptions and SSE events were evaluated. Multi-state Markov models were used to estimate SSE rates adjusted for AC and CHA2DS2-VASC scores. Simulation methods modelled SSE outcomes for the subsequent 7-years based on differing proportional population AC coverage.

Results

AF prevalence increased from 51,492 to 64,852 from 2012–18, with mean CHA2DS2-VASC score increasing from 3.0 to 3.9. AC prescription coverage increased (24,892 [48.3%] to 44,195 [68.1%]), whilst antiplatelet therapy alone or no antithrombotic therapy decreased (14,532 [28.0%] to 5,385 [8.3%] and 26,602 [52.0%] to 21,164 [33.0%] respectively). Hospitalisation rate for SSE in AF population decreased by over 20%, from 1,039 per 100,000 patients/quarter in 2012 to 809 per 100,000 patients/quarter in 2018.

Markov modelling demonstrated a 39% lower SSE rate with AC compared to no AC over time, after adjustment for individual CHA2DS2-VASC (HR=0.61, 95% CI [0.58, 0.63]). Using the estimated progression rates, simulation models shown that an expected 3,574 SSE events per 100,000 per year could have been reduced to 2,956 (17% reduction rate) if AC adherence had been at the now recommended 90% rate from 2012. This model also predicts that improving AC coverage to 90% of patients over the next 7-years would reduce SSE rates by 12% per year (assuming no further increase in mean CHA2DS2-VASC score).

Conclusion

Despite the increase in both prevalence of AF and CHA2DS2-VASC between 2012–18, we observed a progressive decrease in SSE events along with increasing AC prescribing. Our study suggests not only that improved AC coverage is associated with better clinical outcomes, but also that the rate of therapeutic implementation is likely a crucial factor. Reducing transition time between evidence-based guideline publication and widespread clinical uptake of the recommendations appears to be an important opportunity to improve clinical outcomes at a population level and should inform healthcare policy development and implementation.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Funded by research grant

Investigation of traffic behavior in driving accidents in Azarshahr city drivers

Background:

Traffic accidents and losses caused by it are one of the current challenges of human societies that endanger the health of humans and impose a lot of economic costs on the economy of countries. One of the factors in driving accidents is human factors or driving behavior pattern. The pattern of driving behavior, like other human behavior, is influenced by a set of conscious and unconscious factors that are considered as the overall traffic behavior. The aim of this study was to investigate traffic behavior in driving accidents with Manchester driving behavior questionnaire among personal car drivers in Azarshahr city.

Methods:

This study is a research review. It is descriptive-analytic and the necessary information in this design through The Manchester driving behavior questionnaire was collected between 260 drivers. The research environment is the level of Azarshahr city and all the drivers. The data were analyzed by SPSS software version 16.To evaluate the normal distribution of quantitative variables, Kolmogorov-Smirnov test was used and considering that the distribution of variables was not normal for analyzing the difference, Mann-Whitney Test and Spearman test were used for correlation analysis.

Results:

In this study, the Manchester Driving behavior questionnaire, four factors of slippage, intentional violations, errors, and intentional driving violations were clearly differentiated among personal car drivers. In the first factor, the mean score of 1.5, second factor (intentional violations) of 1.85, Third factor (errors) 1.34, the fourth factor (unintentional violation) 1.51.In addition, there was a significant difference in demographic variables between men and women in terms of age, driving history, daily driving hours, and accident number (P <0.001).

Conclusions:

The findings of this study confirmed that the results of intentional driving violations of the highest score and driving slippage are the second rank of driving behaviors among personal vehicles ' drivers in Azarshahr city.

Keywords:

Manchester questionnaire, Driving behavior, Personal vehicle drivers

Zona pellucida-binding protein 2 (ZPBP2) and several proteins containing BX7B motifs in human sperm may have hyaluronic acid binding or recognition properties

STUDY QUESTION

Are there novel hyaladherins in human sperm?

SUMMARY ANSWER

Zona pellucida-binding protein 2 (ZPBP2), containing a Link-like hyaluronic acid (HA)-binding domain, and several other proteins containing BX7B motifs, such as ADAM32 and Midkine, may be novel hyaladherins with HA-binding properties.

WHAT IS KNOWN ALREADY

HA-binding proteins (hyaladherins), which can bind HA surrounding the cumulus-oophorus complex, are distinct from hyases such as PH 20 (SPAM1) and are expressed by mature spermatozoa. Although HABP1 and CD44 are reasonably well characterized hyaladherins and the former has been implicated in sperm-oocyte interactions, the overall significance of sperm hyaladherins for male fertility is still poorly understood.

STUDY DESIGN, SIZE, DURATION

This was a laboratory-based investigation into human sperm hyaladherins undertaken as part of a three year PhD programme sponsored by the EU Marie Curie Training network, Reprotrain.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Protein homogenates of sperm obtained from young men of unknown fertility (N = 4) were partitioned into HA-binding and non-binding fractions by a protein affinity 'panning' method; their subsequent characterization was by liquid chromatography-tandem mass spectrometry (LC-MS-MS) and partitioning behaviour was confirmed by western blotting. Sequences of proteins from both fractions were submitted to PDBsum to look for orthologous entries (PDB codes) and all returned codes were queried against the matching protein using SAS (Sequences Annotated by Structure) looking for structural similarities between them. A systematic search for other common features of hyaladherins was also undertaken.

MAIN RESULTS AND THE ROLE OF CHANCE

The presence of BX7B sequence motifs found in several well-described hyaladherins including RHAMM was used to assess efficacy of potential hyaladherin partitioning by the HA substrate. The data showed that 50% (14/28) and 34.5% (28/81) of proteins in the bound and unbound fractions, respectively, contained these motifs (one-tailed Z-score = 1.45; P = 0.074), indicating weak discrimination by the substrate. Querying PDBsum with sequences for all bound proteins returned several PDB codes matching ZPBP2 with the HA-binding Link domain of the hyaladherin, CD44. Western blot analysis confirmed the affinity partitioning of proteins indicated by the LC-MS/MS results, with ADAM32 (containing two BX7B motifs) and ZPBP2 (containing a Link-like HA-binding domain) present only in the binding fraction. There remains the possibility that the putative hyaladherins uncovered by this study were coincidentally enriched by HA-binding.

LARGE SCALE DATA

The full proteomics data set is available on request.

LIMITATIONS REASONS FOR CAUTION

The protein extraction methods or the HA substrate used to pan them in this study were probably not ideal, as hyaladherins expected to be present in sperm homogenates (such as CD44 and RHAMM) were not detected.

WIDER IMPLICATIONS OF THE FINDINGS

The results provide evidence that ZPBP2, found only in the bound fraction, may have hyaladherin-like properties, which could reflect the evolutionary background context of contemporary sperm-oocyte interaction mechanisms.

STUDY FUNDING AND COMPETING INTEREST(S)

An EU Marie Curie Sklodowska Initial Training Network Scholarship, supporting Ms Torabi, is gratefully acknowledged. This project was also supported and funded by the Efficacy and Mechanism Evaluation Programme, a UK MRC and NIHR partnership (Grant No 11/14/ 34). There is no conflict of interest in relation to this work.

Correlation between anthropometric indices at birth and developmental delay in children aged 4-60 months in Isfahan, Iran

Background

Advances in medical knowledge and treatment modalities have resulted in an increased survival rate for high-risk infants. This increased number of survivors enables study of the future development of these children. Other than infection and trauma, developmental and behavioral problems are the most common medical problems among such children. This study sought correlations between anthropometric indices at birth and developmental delay in children aged 4–60 months who visited health service centers affiliated with the Isfahan University of Medical Sciences in 2010.

Methods

In this descriptive, correlational study, 401 children aged 4–60 months and visiting health service centers were selected using a multistage method. Anthropometric indices at birth were collected from their health care records, and developmental status was measured using the Ages and Stages Questionnaire, the validity (0.84) and reliability (0.94) of which were obtained from a previous study.

Results

The mean age of the children in the normal group was 17.33 ± 13.18 months and that in the developmental delay group was 29.92 ± 19.19 months. Most children in the normal group were female (56%) and in the developmental delay group were male (55.2%). No correlation was found between height and head circumference at birth and developmental delay. However, the birth weight of children with developmental delay was four times lower than that of children with normal development (P = 0.004, odds ratio 4).

Conclusion

Birth weight and male gender were factors that strongly correlated with developmental delay in this study.

Clinical response to targeted radionuclide therapy with multiple 500 mCi doses of 111In-pentetreotide in patients with progressive neuroendocrine tumors

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Background: Patients with advanced stage neuroendocrine tumors have limited therapeutic options. Previous treatments with doses up to 360 mCi per fraction have shown promising results in stabilizing progressive disease. The intent of this study was to evaluate the efficacy and safety of 2 consecutive 500 mCi doses of 111In-pentetreotide in patients with progressive neuroendocrine tumors. This study was performed according to an FDA approved IND application. Methods: In a non-randomized study, 18 patients (13 men, 5 women) with an average age of 59 (ranging from 41–83 yr.) received 2 cycles of 500 mCi 111In-pentetreotide infused over 3 to 6 hours (avg. cumulative dose range: 955–1006.1 mCi). All patients had progressive neuroendocrine tumors and failed first line therapy. All patients had grade 3 to 5 uptake in the tumors in the pre-therapy diagnostic 111In-pentetreotide scan. The primary endpoint was clinical, metabolic and imaging response using RECIST criteria. Early and long term hematological, renal and hepatic toxicities during the average follow up period of 9.87 months (range 3.93 to 17.23 months) was performed using NCI Common Toxicities criteria. Results: Sixteen out of 18 patients with previously progressive disseminated neuroendocrine disease achieved stable disease by imaging criteria. Metabolic response defined as 25% or more decline in Chromogranin or other markers was achieved in 72% of the patients. Clinical response defined by Functional Living Index (FLI) questionnaire and physical exam was achieved in 84% of the patients. Ten patients (55%) had grade I or II hematological toxicities, one patient had grade III thrombocytopenia, with nadir mean of 5 weeks after therapy. None of the patients required supportive therapy. Duration of hematological toxicities ranged from 1–6 weeks). One patient had grade II liver toxicity which appeared 4 weeks after therapy and resolved on week 5. No renal toxicity was observed during the follow-up period. Conclusions: Multiple 500 mCi doses of 111In-pentetreotide therapy are effective in patients with progressive disseminated neuroendocrine tumors. Safety profile of this regimen suggests the opportunity for non-myeloablative dose escalation.

No significant financial relationships to disclose.

Predicting Brine Mixing Deep Within the Reservoir and Its Impact on Scale Control in Marginal and Deepwater Developments

Summary

Sulphate scale deposition is a common problem in hydrocarbon reservoirs in which injection seawater that is rich in sulphate mixes with formation brines that are rich in barium, strontium, and calcium. Deposition of these scales can cause significant production impairment if it occurs within zones near the production wellbores. To control scale deposition in the near-wellbore region of a reservoir, scale squeeze treatments are commonly deployed. In cases in which scale severity is very high, removal of sulphate ions from the injection water is an alternative scale-control strategy. Both these mitigation methods have associated capital (CAPEX) (e.g., desulphation plant) and operating expenditures (OPEX) (e.g., scale squeeze treatments).

To assess the severity of the problem in new fields, thermodynamic calculations typically are performed to calculate the mass of scale that will form. Until recently, little work has been carried out to identify the location of scale formation within the reservoir. In this paper, field data and flow simulations from three North Sea fields are presented to show that scale formation can, in fact, occur deep within the reservoir and can have a negligible negative impact on oil production in the near-wellbore region.

Evidence is presented from these North Sea fields that shows the evolution of the brine chemistry as seawater breakthrough occurs and as squeeze treatments are applied. The evidence from the produced brine chemistry is linked to flow calculations for these fields to show that in some systems scale is depositing deep within the reservoir, reducing the potential for damage in the near production wellbore region. The extent and impact of the deposition varies throughout the reservoir and can be quantified. Modeling brine mixing and stripping of the scaling ions before the fluids reach the production wellbore has a significant impact on the economic assessment of marginal fields and deepwater developments. In such fields, the technical challenge and cost (CAPEX/ OPEX) of scale control might make development uneconomical. This paper outlines the data requirements and methodology used to allow such an assessment to be made.

Introduction

Flow assurance is an essential aspect in the economic production of hydrocarbons. It can be considered as the ability to produce petroleum fluids economically from the reservoir to a production facility during the life of a field. Scale control is a key aspect of flow assurance. The increasing number of subsea wells and deepwater developments raises particular issues and challenges for flow assurance beyond those seen for simple vertical wells. The complexity of new well completions in terms of horizontal and multilateral wells, subsea tiebacks, and commingled flow presents particular challenges. The scale-inhibitor treatments required for such complex wells are often associated with very high intervention costs.

Scale-control issues need to be addressed as part of asset lifecycle management in which the issues are tackled before field development/production (CAPEX phase) rather than confronting them in a reactive manner once water breakthrough occurs (OPEX phase). Such an approach allows for selection of appropriate economic technology. Indeed, the anticipated problems may influence the plans to develop a field, for example, in terms of water injection strategies or implementing appropriate technology upon well completion.

Scale control in life-cycle management is based on the varying challenges seen with the increase in water cut as a field and its wells move from dry production to high water cuts. This is associated with four phases of field development - project, plateau, decline, and decommission. Scale-control treatment strategies should be developed at the project stage. The scale issues at subsequent stages depend on the nature and severity of the anticipated scale problem. One class of issues is associated with natural depletion (Fig. 1) in which the subsequent scale problems are normally restricted to calcium carbonate formation. Carbonate scale formation occurs when connate or aquifer water passes through the bubblepoint and carbon dioxide evolves. As carbon dioxide evolves, the solubility declines rapidly with respect to carbonates and forms a precipitate with divalent ions, such as iron and, more commonly, calcium. Where water injection (seawater or aquifer) is used for pressure maintenance and sweep, mixing incompatible brines can lead to the formation of sulphate scales when the injection water contains sulphate ions (see Fig. 2).

In a production operation in which barium is present within the formation water and seawater is the injected fluid, the principal flow-assurance risk is barium sulphate scale because of its very low solubility relative to calcium carbonate and strontium and calcium sulphate scales. Where severe sulphate scaling is anticipated, the potential for desulphation of injection water may need to be evaluated.1 While new technologies have been introduced for addressing the different scale-control issues, a review of technology alongside risk and economics can provide guidance for new developments based on historical data. It can also aid option selection for currently producing fields and highlight areas in which technology gaps exist.

A better understanding of the scale problem, based on modeling water chemistry and fluid flow/mixing within the formation and the wellbore, will allow a better economic assessment of the various scale-control options.2 An assessment of the risk scale can have on well integrity must always be made. This should be based on the actual scaling tendency of the brine, which is evaluated by performing the type of mixing and reaction calculations presented here.

The process of evaluating the risk of scale in a field under appraisal is outlined later, including the factors to take into account when evaluating the risk of scale formation and control.

Scale Management Economics

Simple economic models can be used to assess various scale-management options during field life. The various costs for all scale-related interventions should be considered and ranked against the development type. Such models are particularly useful in deepwater developments in which the option may exist for subsea wells, dry trees, and possibly sulphate reduction to help mitigate sulphate scale.