Systematic literature review comparing clinical utility of heparin-bonded expanded polytetrafluoroethylene graft to autologous saphenous vein graft for management of below-knee peripheral arterial disease.

INTRODUCTION: This systematic literature review compares the clinical outcomes of heparin-bonded expanded polytetrafluoroethylene with autologous saphenous vein in the management of patients undergoing below-the-knee bypass to treat peripheral arterial disease. METHODS: An electronic literature search was conducted in MEDLINE and EMBASE to identify comparative studies in patients undergoing below-the-knee surgical bypass. Studies were screened at abstract and full text review using pre-defined inclusion criteria by two independent reviewers and critically appraised for risk of bias. Meta-analyses were conducted using Review Manager 5 software (Nordic Cochrane Centre, Copenhagen, Denmark). RESULTS: Eight retrospective cohort studies were identified. Meta-analysis of primary patency demonstrated no significant difference between heparin-bonded expanded polytetrafluoroethylene and autologous saphenous vein grafts after one year (0.91 [0.52-1.59], P=0.74), two years (1.12 [0.60-2.10], P=0.77), three years (0.62 [0.26-1.48], P=0.28) and 4 years [0.36 -1.39], P=0.31). Similarly, for secondary patency, no significant difference was detected at one (0.62 [0.33-1.15], P=0.13), two (0.83 [0.32-2.13], P=0.69), three (0.60 [0.27-1.32], P=0.20) and 4 years (0.66 [0.32-1.36], P=0.26) respectively. There was no significant difference between autologous veins and heparin-bonded expanded polytetrafluoroethylene for limb salvage and mortality at all timepoints. A sensitivity analysis to compare outflow vessel was conducted in only tibial bypass identified no differences. All analyses were considered at high-risk bias due to heterogeneity in study populations and attrition in follow-up. CONCLUSION: This meta-analysis demonstrates similar outcomes between autologous saphenous vein and heparin-bonded expanded polytetrafluoroethylene for patency, limb salvage, and mortality through 4 years. Primary and secondary patency are superior at four years with autologous veins, but limb salvage and overall survival remained similar. The use of heparin-bonded expanded polytetrafluoroethylene synthetic grafts is a satisfactory option to prevent amputation, particularly when autologous saphenous vein grafts are not available. Controlled clinical studies are needed to further inform future decision making and economic modeling related to the choice of conduit for below-the-knee graft construction.

UK cost-effectiveness analysis of endoscopic sleeve gastroplasty versus lifestyle modification alone for adults with class II obesity.

BACKGROUND: Endoscopic sleeve gastroplasty (ESG) is a minimally invasive procedure that has been demonstrated in the MERIT randomised, controlled trial to result in substantial and durable additional weight loss in adults with obesity compared with lifestyle modification (LM) alone. We sought to conduct the first cost-effectiveness analysis of ESG versus LM alone in adults with class II obesity (BMI 35.0-39.9 kg/m2) from a national healthcare system perspective in England based on results from this study. METHODS: A 6-state Markov model was developed comprising 5 BMI-based health states and an absorbing death state. Baseline characteristics, utilities, and transition probabilities were informed by patient-level data from the subset of patients with class II obesity in MERIT. Adverse events (AEs) were based on the MERIT safety population. Mortality was estimated by applying BMI-specific hazard ratios from the published literature to UK general population mortality rates. Utilities for the healthy weight and overweight health states were informed from the literature; disutility associated with increasing BMI in the class I-III obesity health states was estimated using MERIT utility data. Disutility due to AEs and the prevalence of obesity-related comorbidities were based on the literature. Costs included intervention costs, AE costs, and comorbidity costs. RESULTS: ESG resulted in higher overall costs than LM alone but led to an increase in quality-adjusted life years (QALYs). The incremental cost-effectiveness ratio (ICER) for ESG vs LM alone was £2453/QALY gained. ESG was consistently cost effective across a wide range of sensitivity analyses, with no ICER estimate exceeding £10,000/QALY gained. In probabilistic sensitivity analysis, the mean ICER was £2502/QALY gained and ESG remained cost effective in 98.25% of iterations at a willingness-to-pay threshold of £20,000/QALY. CONCLUSION: Our study indicates that ESG is highly cost effective versus LM alone for the treatment of adults with class II obesity in England.

Clinical effectiveness and safety of erythropoietin-stimulating agents for the treatment of low- and intermediate-1-risk myelodysplastic syndrome: a systematic literature review.

Many patients with lower-risk myelodysplastic syndrome (MDS) experience anaemia, which has negative consequences. Erythropoiesis-stimulating agents (ESAs) and their biosimilars are used to treat anaemia in MDS and, currently, epoetin alfa and darbepoetin alfa are commonly used and recommended by clinical guidelines. To better understand the evidence available on the use of ESAs for anaemia in lower-risk MDS, we conducted a systematic literature review to identify randomized and nonrandomized prospective studies reporting on clinical efficacy/effectiveness, patient-reported quality of life (QoL), and safety. We extended our review to include retrospective studies for darbepoetin alfa specifically and to ascertain the feasibility of completing an indirect network meta-analysis comparing epoetin and darbepoetin alfa. Overall, 53 articles reporting on 35 studies were included. The studies indicated a clinical benefit of ESAs, with benefits observed across key clinical outcomes. ESAs showed consistent improvement in erythroid response rates (ESA-naïve, 45-73%; previous ESA exposure, 25-75%) and duration of response. Comparative studies demonstrated similar progression to acute myeloid leukaemia and several showed improved overall survival and QoL. Limited safety concerns were identified. This analysis confirmed ESA therapy should be the foremost first-line treatment of anaemia in most patients with lower-risk MDS who lack the 5q deletion.

Economic evaluation of covered stents for transjugular intrahepatic portosystemic stent shunt in patients with variceal bleeding and refractory ascites secondary to cirrhosis.

OBJECTIVES: Transjugular intrahepatic portosystemic stent shunt (TIPSS) is clinically effective in variceal bleeding and refractory ascites; however, the cost-effectiveness of TIPSS has yet to be evaluated in the UK. This study aimed to establish the cost-effectiveness of (i) pre-emptive TIPSS versus endoscopic band ligation (EBL) in populations with variceal bleeding and (ii) TIPSS versus large volume paracentesis (LVP) in refractory ascites. METHODS: A cost-utility analysis was conducted with the perspective including healthcare costs and quality-adjusted life years (QALYs). A Markov model was constructed with a 2-year time horizon, health states for mortality and survival and probabilities for the development of variceal bleeding, ascites and hepatic encephalopathy. A survival analysis was conducted to extrapolate 12-month to 24-month mortality for the refractory ascites indication. Uncertainty was analysed in deterministic and probabilistic sensitivity analyses. RESULTS: TIPSS was cost-effective (dominant) and cost saving for both indications. For variceal bleeding, pre-emptive TIPSS resulted in 0.209 additional QALYs, and saved £600 per patient compared with EBL. TIPSS had a very high probability of being cost-effective (95%) but was not cost saving in scenario analyses driven by rates of variceal rebleeding. For refractory ascites, TIPSS resulted in 0.526 additional QALYs and saved £17 983 per patient and had a 100% probability of being cost-effective and cost saving when compared with LVP. CONCLUSIONS: TIPSS is a cost-effective intervention for variceal bleeding and refractory ascites. TIPSS is highly cost-saving for refractory ascites. Robust randomised trial data are required to confirm whether pre-emptive TIPSS is cost saving for variceal bleeding.

Evaluating Cost-Effectiveness Models for Pharmacologic Interventions in Adults with Heart Failure: A Systematic Literature Review.

BACKGROUND: Heart failure (HF) is a well-recognized public health concern and imposes high economic and societal costs. Decision analytic models exist for evaluating the economic ramifications associated with HF. Despite this, studies that appraise these modelling approaches for augmenting best-practice decisions remain scarce. OBJECTIVE: Our objective was to conduct a systematic literature review (SLR) of published economic models for the management of HF and describe their general and methodological features. METHODS: This SLR employed a combination of relevant search terms associated with HF, which were used in a number of databases, including MEDLINE, Embase, the National Health Service Economic Evaluation Database, Cost-Effectiveness Analysis Registry, ScHARR Health Utilities Database and Cochrane Library Database. A number of model features (i.e. model structure, specification, outcomes assessed, scenario and sensitivity analysis, key model drivers) were extracted and subsequently summarized. RESULTS: Of 64 publications retained, a selection of modelling approaches were identified, including Markov (n = 28), trial-based analytic (n = 22), discrete-event simulation (n = 6), survival analytic (n = 7) and decision-tree modelling (n = 1) approaches. The bulk of publications employed either a cost-utility (n = 27) or cost-effectiveness (n = 36) analysis and evaluated more than one study outcome, which typically included overall costs (n = 59), incremental cost-effectiveness ratios (n = 55), life-years gained (n = 48) and willingness-to-pay thresholds (n = 37). Most publications focused on patients with chronic HF (n = 40) and used New York Heart Association (NYHA) disease classifications to categorize patients and determine disease severity. Few (n = 19) publications documented the use of hospitalization states for modelling patient outcomes and associated costs. A quality assessment of the included publications revealed most articles demonstrated reasonable methodological value. CONCLUSIONS: We identified numerous decision analytic modelling approaches for evaluating the cost effectiveness of pharmacologic treatments in HF. A Markov cohort model approach was most commonly used, and most models relied on NYHA classes as a proxy of HF severity, disease progression and prognosis.

Real-world cardiovascular disease burden in patients with atherosclerotic cardiovascular disease: a comprehensive systematic literature review.

OBJECTIVE: Based on randomized controlled trials (RCTs), non-fatal myocardial infarction (MI) rates range between 9 and 15 events per 1000 person-years, ischemic stroke between 4 and 6 per 1000 person-years, CHD death rates between 5 and 7 events per 1000 person-years, and any major vascular event between 28 and 53 per 1000 person-years in patients with atherosclerotic cardiovascular disease (ASCVD). We reviewed global literature on the topic to determine whether the real-world burden of secondary major adverse cardiovascular events (MACEs) is higher among ASCVD patients. METHODS: We searched PubMed and Embase using MeSH/keywords including cardiovascular disease, secondary prevention and observational studies. Studies published in the last 5 years, in English, with ≥50 subjects with elevated low-density lipoprotein cholesterol (LDL-C) or on statins, and reporting secondary MACEs were included. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of each included study. RESULTS: Of 4663 identified articles, 14 studies that reported MACE incidence rates per 1000 person-years were included in the review (NOS grades ranged from 8 to 9; 2 were prospective and 12 were retrospective studies). Reported incidence rates per 1000 person-years had a range (median) of 12.01-39.9 (26.8) for MI, 13.8-57.2 (41.5) for ischemic stroke, 1.0-94.5 (21.1) for CV-related mortality and 9.7-486 (52.6) for all-cause mortality. Rates were 25.8-211 (81.1) for composite of MACEs. Multiple event rates had a range (median) of 60-391 (183) events per 1000 person-years. CONCLUSIONS: Our review indicates that MACE rates observed in real-world studies are substantially higher than those reported in RCTs, suggesting that the secondary MACE burden and potential benefits of effective CVD management in ASCVD patients may be underestimated if real-world data are not taken into consideration.

The archetype enhancer of simian virus 40 DNA is duplicated during virus growth in human cells and rhesus monkey kidney cells but not in green monkey kidney cells.

Archetype SV40, obtained directly from its natural host, is characterized by a single 72-bp enhancer element. In contrast, SV40 grown in cell culture almost invariably exhibits partial or complete duplication of the enhancer region. This distinction has been considered important in studies of human tumor material, since SV40-associated tumor isolates have been described having a single enhancer region, suggesting natural infection as opposed to possible contamination by laboratory strains of virus. However, the behavior of archetypal SV40 in cultured cells has never been methodically studied. In this study we reengineered nonarchetypal 776-SV40 to contain a single 72-bp enhancer region and used this reengineered archetypal DNA to transfect a number of simian and human cell lines. SV40 DNA recovered from these cells was analyzed by restriction endonuclease analysis, PCR, and DNA sequencing. Reengineered archetype SV40 propagated in green monkey TC-7 or BSC-1 kidney cells remained without enhancer region duplication even after extensive serial virus passage. Archetype SV40 grown in all but one of the rhesus or human cell lines initially appeared exclusively archetypal. However, when virus from these cell types was transferred to green monkey cells, variants with partial enhancer duplication appeared after as little as a single passage. These findings suggest (1) that virus with a single 72-bp enhancer may persist in cultured cells of simian and human origin; (2) that variants with partially duplicated enhancer regions may arise within cell lines in quantities below limits of detection; (3) that these variants may enjoy a selective advantage in cell types other than those from which they arose (e.g., green monkey kidney cells); and (4) that certain cell lines may support a selective growth advantage for the variants without supporting their formation. Our data indicate that enhancer duplication may also occur in human as well as rhesus kidney cells. Thus, detection of enhancer region duplication may not, a priori, indicate laboratory contamination, nor does detection of a single 72-bp enhancer exclude the possibility that contamination may have occurred. These findings may be of relevance to studies attempting to detect SV40 DNA in human tumors or other clinical specimens.

Propagation of archetype and nonarchetype JC virus variants in human fetal brain cultures: demonstration of interference activity by archetype JC virus.

In immunologically normal individuals, the polyomavirus, JC virus (JCV), produces an asymptomatic primary infection followed by lifelong persistence of the virus in renal tubular epithelial cells. In some immunocompromised patients, however, in particular acquired immunodeficiency syndrome (AIDS) patients, JCV causes an opportunistic central nervous system (CNS) disorder, progressive multifocal leukoencephalopathy (PML). JCV DNA as it persists in kidneys (archetypal JCV) and JCV DNA isolated from PML lesions show differences in their regulatory regions in which transcription and replication are controlled. Archetypal JCV DNA has a single enhancer and no rearrangements or deletions in the regulatory region. In contrast, JCV DNA from PML isolates is characterized by alterations in the regulatory region. Some PML-associated JCVs can be grown in cultures of human fetal brain (HFB) cells. Growth of archetypal JCV in cultured cells has not been reported, however. Here we demonstrate successful propagation of the archetypal JCV, strain GS/K, in HFB cells. Growth occurred more slowly and to lower titers than is seen with the prototypical PML JCV strain Mad-1, with relatively few cells containing viral T antigen (T-Ag) or viral capsid protein, Vp1. Interestingly, GS/K growth could be enhanced, with a large increase in viral DNA and cytopathic effect, by coinfection with GS/B, a nonarchetypal brain-derived JCV variant isolated from the same PML patient as GS/K. The amount of GS/K DNA was also greatly enhanced when it was cotransfected with Mad-1 JCV DNA, the prototypical PML isolate. In contrast to GS/K plus GS/B-cotransfected cells, in GS/K plus Mad-1-infected cells, cytopathic effect was not increased. On subsequent passage of culture lysates to naïve cells, however, the infection produced by either combination of viral DNAs slowed, no cytopathic effect (CPE) was present, and the amount of GS/B or Mad-1 viral DNA was greatly reduced as compared to that of GS/K DNA. These data suggest that GS/K was able to use either GS/B or Mad-1 as a helper and that GS/K was in turn able to interfere with the growth of either helper virus. Archetype JCV can be successfully propagated in HFB cells, although infection develops much more slowly than that caused by the PML JCV variant Mad-1. The ability of archetypal and variant JCVs to enhance or retard each other's replication may have implications in vivo for the maintenance of JCV persistence and the growth of JCV variants.