The STAMPEDE2 Trial: a Site Survey of Current Patterns of Care, Access to Imaging and Treatment of Metastatic Prostate Cancer

AIMS

The forthcoming STAMPEDE2 trial has three comparisons in metastatic hormone-sensitive prostate cancer. We aim to determine clinical practices among STAMPEDE trial investigators for access to imaging and therapeutic choices and explore their interest in participation in STAMPEDE2.

MATERIALS AND METHODS

The survey was developed and distributed online to 120 UK STAMPEDE trial sites. Recipients were invited to complete the survey between 16 and 30 May 2022. The survey consisted of 30 questions in five sections on access to stereotactic ablative body radiotherapy (SABR), 177lutetium-prostate-specific membrane antigen-617 (177Lu-PSMA-617), choice of systemic therapies and use of positron emission tomography/computerised tomography and whole-body magnetic resonance imaging.

RESULTS

From 58/120 (48%) sites, 64 respondents completed the survey: 55/64 (86%) respondents were interested to participate in SABR, 44/64 (69%) in 177Lu-PSMA-617 and 56/64 (87.5%) in niraparib with abiraterone comparisons; 45/64 (70%) respondents had access to bone, spine and lymph node metastases SABR delivery and 7/64 (11%) to 177Lu-PSMA-617. In addition to androgen deprivation therapy, 60/64 (94%) respondents used androgen receptor signalling inhibitors and 46/64 (72%) used docetaxel; 29/64 (45%) respondents would consider triplet therapy with androgen deprivation therapy, androgen receptor signalling inhibitors and docetaxel. Positron emission tomography/computerised tomography was available to 62/64 (97%) respondents and requested by 45/64 (70%) respondents for disease uncertainty on conventional imaging and 39/64 (61%) at disease relapse. Whole-body magnetic resonance imaging was available to 24/64 (38%) respondents and requested by 13/64 (20%) respondents in highly selected patients. In low-volume disease, 38/64 (59%) respondents requested scans at baseline and disease relapse. In high-volume disease, 29/64 (45%) respondents requested scans at baseline, best response (at prostate-specific antigen nadir) and disease relapse; 54/64 (84%) respondents requested computerised tomography and bone scan for best response assessment.

CONCLUSION

There is noteworthy disparity in clinical practice across current study sites, however most have expressed an interest in participation in the forthcoming STAMPEDE2 trial.

Genomic characterisation of hormone receptor-positive breast cancer arising in very young women

BACKGROUND

Very young premenopausal women diagnosed with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+HER2-) early breast cancer (EBC) have higher rates of recurrence and death for reasons that remain largely unexplained.

PATIENTS AND METHODS

Genomic sequencing was applied to HR+HER2- tumours from patients enrolled in the Suppression of Ovarian Function Trial (SOFT) to determine genomic drivers that are enriched in young premenopausal women. Genomic alterations were characterised using next-generation sequencing from a subset of 1276 patients (deep targeted sequencing, n = 1258; whole-exome sequencing in a young-age, case-control subsample, n = 82). We defined copy number (CN) subgroups and assessed for features suggestive of homologous recombination deficiency (HRD). Genomic alteration frequencies were compared between young premenopausal women (<40 years) and older premenopausal women (≥40 years), and assessed for associations with distant recurrence-free interval (DRFI) and overall survival (OS).

RESULTS

Younger women (<40 years, n = 359) compared with older women (≥40 years, n = 917) had significantly higher frequencies of mutations in GATA3 (19% versus 16%) and CN amplifications (CNAs) (47% versus 26%), but significantly lower frequencies of mutations in PIK3CA (32% versus 47%), CDH1 (3% versus 9%), and MAP3K1 (7% versus 12%). Additionally, they had significantly higher frequencies of features suggestive of HRD (27% versus 21%) and a higher proportion of PIK3CA mutations with concurrent CNAs (23% versus 11%). Genomic features suggestive of HRD, PIK3CA mutations with CNAs, and CNAs were associated with significantly worse DRFI and OS compared with those without these features. These poor prognostic features were enriched in younger patients: present in 72% of patients aged <35 years, 54% aged 35-39 years, and 40% aged ≥40 years. Poor prognostic features [n = 584 (46%)] versus none [n = 692 (54%)] had an 8-year DRFI of 84% versus 94% and OS of 88% versus 96%. Younger women (<40 years) had the poorest outcomes: 8-year DRFI 74% versus 85% and OS 80% versus 93%, respectively.

CONCLUSION

These results provide insights into genomic alterations that are enriched in young women with HR+HER2- EBC, provide rationale for genomic subgrouping, and highlight priority molecular targets for future clinical trials.

Plasma and rectal mucosal oxylipin levels during aspirin and eicosapentaenoic acid treatment in the seAFOod polyp prevention trial

BACKGROUND

Aspirin and eicosapentaenoic acid (EPA) have colorectal polyp prevention activity, alone and in combination. This study measured levels of plasma and rectal mucosal oxylipins in participants of the seAFOod 2 × 2 factorial, randomised, placebo-controlled trial, who received aspirin 300 mg daily and EPA 2000 mg free fatty acid, alone and in combination, for 12 months.

METHODS

Resolvin (Rv) E1, 15-epi-lipoxin (LX) A₄ and respective precursors 18-HEPE and 15-HETE (with chiral separation) were measured by ultra-high performance liquid chromatography-tandem mass spectrometry in plasma taken at baseline, 6 months and 12 months, as well as rectal mucosa obtained at trial exit colonoscopy at 12 months, in 401 trial participants.

RESULTS

Despite detection of S- and R- enantiomers of 18-HEPE and 15-HETE in ng/ml concentrations, RvE1 or 15‑epi-LXA₄ were not detected above a limit of detection of 20 pg/ml in plasma or rectal mucosa, even in individuals randomised to both aspirin and EPA. We have confirmed in a large clinical trial cohort that prolonged (12 months) treatment with EPA is associated with increased plasma 18-HEPE concentrations (median [inter-quartile range] total 18-HEPE 0.51 [0.21-1.95] ng/ml at baseline versus 0.95 [0.46-4.06] ng/ml at 6 months [P<0.0001] in those randomised to EPA alone), which correlate strongly with respective rectal mucosal 18-HEPE levels (r = 0.82; P<0.001), but which do not predict polyp prevention efficacy by EPA or aspirin.

CONCLUSION

Analysis of seAFOod trial plasma and rectal mucosal samples has not provided evidence of synthesis of the EPA-derived specialised pro-resolving mediator RvE1 or aspirin-trigged lipoxin 15‑epi-LXA₄. We cannot rule out degradation of individual oxylipins during sample collection and storage but readily measurable precursor oxylipins argues against widespread degradation.

PROMIS--Prostate MR imaging study: A paired validating cohort study evaluating the role of multi-parametric MRI in men with clinical suspicion of prostate cancer

BACKGROUND

Transrectal ultrasound-guided prostate biopsies are prone to detection errors. Multi-parametric MRI (MP-MRI) may improve the diagnostic pathway.

METHODS

PROMIS is a prospective validating paired-cohort study that meets criteria for level 1 evidence in diagnostic test evaluation. PROMIS will investigate whether multi-parametric (MP)-MRI can discriminate between men with and without clinically-significant prostate cancer who are at risk prior to first biopsy. Up to 714 men will have MP-MRI (index), 10-12 core TRUS-biopsy (standard) and 5mm transperineal template mapping (TPM) biopsies (reference). The conduct and reporting of each test will be blinded to the others.

RESULTS

PROMIS will measure and compare sensitivity, specificity, and positive and negative predictive values of both MP-MRI and TRUS-biopsy against TPM biopsies. The MP-MRI results will be used to determine the proportion of men who could safely avoid biopsy without compromising detection of clinically-significant cancers. For the primary outcome, significant cancer on TPM is defined as Gleason grade >/= 4+3 and/or maximum cancer core length of ≥ 6 mm. PROMIS will also assess inter-observer variability among radiologists among other secondary outcomes. Cost-effectiveness of MP-MRI prior to biopsy will also be evaluated.

CONCLUSIONS

PROMIS will determine whether MP-MRI of the prostate prior to first biopsy improves the detection accuracy of clinically-significant cancer.

Systematic review and meta-analysis of the growth and rupture rates of small abdominal aortic aneurysms: implications for surveillance intervals and their cost-effectiveness

BACKGROUND

Small abdominal aortic aneurysms (AAAs; 3.0-5.4 cm in diameter) are usually asymptomatic and managed by regular ultrasound surveillance until they grow to a diameter threshold (commonly 5.5 cm) at which surgical intervention is considered. The choice of appropriate surveillance intervals is governed by the growth and rupture rates of small AAAs, as well as their relative cost-effectiveness.

OBJECTIVES

The aim of this series of studies was to inform the evidence base for small AAA surveillance strategies. This was achieved by literature review, collation and analysis of individual patient data, a focus group and health economic modelling.

DATA SOURCES

We undertook systematic literature reviews of growth rates and rupture rates of small AAAs. The databases MEDLINE, EMBASE on OvidSP, Cochrane Central Register of Controlled Trials 2009 Issue 4, ClinicalTrials.gov, and controlled-trials.com were searched from inception up until the end of 2009. We also obtained individual data on 15,475 patients from 18 surveillance studies.

REVIEW METHODS

Systematic reviews of publications identified 15 studies providing small AAA growth rates, and 14 studies with small AAA rupture rates, up to December 2009 (later updated to September 2012). We developed statistical methods to analyse individual surveillance data, including the effects of patient characteristics, to inform the choice of surveillance intervals and provide inputs for health economic modelling. We updated an existing health economic model of AAA screening to address the cost-effectiveness of different surveillance intervals.

RESULTS

In the literature reviews, the mean growth rate was 2.3 mm/year and the reported rupture rates varied between 0 and 1.6 ruptures per 100 person-years. Growth rates increased markedly with aneurysm diameter, but insufficient detail was available to guide surveillance intervals. Based on individual surveillance data, for each 0.5-cm increase in AAA diameter, growth rates increased by about 0.5 mm/year and rupture rates doubled. To control the risk of exceeding 5.5 cm to below 10% in men, on average a 7-year surveillance interval is sufficient for a 3.0-cm aneurysm, whereas an 8-month interval is necessary for a 5.0-cm aneurysm. To control the risk of rupture to below 1%, the corresponding estimated surveillance intervals are 9 years and 17 months. Average growth rates were higher in smokers (by 0.35 mm/year) and lower in patients with diabetes (by 0.51 mm/year). Rupture rates were almost fourfold higher in women than men, doubled in current smokers and increased with higher blood pressure. Increasing the surveillance interval from 1 to 2 years for the smallest aneurysms (3.0-4.4 cm) decreased costs and led to a positive net benefit. For the larger aneurysms (4.5-5.4 cm), increasing surveillance intervals from 3 to 6 months led to equivalent cost-effectiveness.

LIMITATIONS

There were no clear reasons why the growth rates varied substantially between studies. Uniform diagnostic criteria for rupture were not available. The long-term cost-effectiveness results may be susceptible to the modelling assumptions made.

CONCLUSIONS

Surveillance intervals of several years are clinically acceptable for men with AAAs in the range 3.0-4.0 cm. Intervals of around 1 year are suitable for 4.0-4.9-cm AAAs, whereas intervals of 6 months would be acceptable for 5.0-5.4-cm AAAs. These intervals are longer than those currently employed in the UK AAA screening programmes. Lengthening surveillance intervals for the smallest aneurysms was also shown to be cost-effective. Future work should focus on optimising surveillance intervals for women, studying whether or not the threshold for surgery should depend on patient characteristics, evaluating the usefulness of surveillance for those with aortic diameters of 2.5-2.9 cm, and developing interventions that may reduce the growth or rupture rates of small AAAs.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Long-term cost-effectiveness analysis of endovascular versus open repair for abdominal aortic aneurysm based on four randomized clinical trials

Background

A number of published economic evaluations of elective endovascular aneurysm repair (EVAR) versus open repair for abdominal aortic aneurysm (AAA) have come to differing conclusions about whether EVAR is cost-effective. This paper reviews the current evidence base and presents up-to-date cost-effectiveness analyses in the light of results of four randomized clinical trials: EVAR-1, DREAM, OVER and ACE.

Methods

Markov models were used to estimate lifetime costs from a UK perspective and quality-adjusted life-years (QALYs) based on the results of each of the four trials. The outcomes included in the model were: procedure costs, surveillance costs, reintervention costs, health-related quality of life, aneurysm-related mortality and other-cause mortality. Alternative scenarios about complications, reinterventions and deaths beyond the trial were explored.

Results

Models based on the results of the EVAR-1, DREAM or ACE trials did not find EVAR to be cost-effective at thresholds used in the UK (up to £30 000 per QALY). EVAR seemed cost-effective according to models based on the OVER trial. These results seemed robust to alternative model scenarios about events beyond the trial intervals.

Conclusion

These analyses did not find that EVAR is cost-effective compared with open repair in the long term in trials conducted in European centres. EVAR did appear to be cost-effective based on the OVER trial, conducted in the USA. Caution must be exercised when transferring the results of economic evaluations from one country to another.

Meta-analysis of individual patient data to examine factors affecting growth and rupture of small abdominal aortic aneurysms

Background

Surveillance is a common management strategy for small abdominal aortic aneurysm (AAA) (3·0–5·4 cm in diameter). Individual characteristics, other than diameter, may influence aneurysm growth or rupture rates.

Methods

Individual data were collated from 15 475 people under follow-up for a small aneurysm in 18 studies. The influence of co-variables (including demographics, medical and drug history) on aneurysm growth and rupture rates (analysed using longitudinal random-effects modelling and survival analysis with adjustment for aneurysm diameter) were summarized in an individual patient meta-analysis.

Results

The mean aneurysm growth rate of 2·21 mm/year was independent of age and sex. Growth rate was increased in smokers (by 0·35 mm/year) and decreased in patients with diabetes (by 0·51 mm/year). Mean arterial pressure had no effect and antihypertensive or other cardioprotective medications had only small, non-significant effects on aneurysm growth, consistent with the observation that calendar year of enrolment was not associated with growth rate. Rupture rates were almost fourfold higher in women than men (P &lt; 0·001), were double in current smokers (P = 0·001) and increased with higher blood pressure (P = 0·001).

Conclusion

Follow-up schedules for individuals with a small AAA may need to consider diabetes and smoking, in addition to aneurysm diameter. The differing risk factors for growth and rupture suggest that a lower threshold for surgical intervention in women may be justified. No single drug used for cardiovascular risk reduction had a major effect on the growth or rupture of small aneurysms.

Incidence of cardiovascular events and death after open or endovascular repair of abdominal aortic aneurysm in the randomized EVAR trial 1

BACKGROUND

The aim was to compare rates of myocardial infarction, stroke and cardiovascular death in patients with a large abdominal aortic aneurysm who had endovascular (EVAR) or open repair to determine whether cardiovascular mortality explains the convergence in survival curves after these procedures.

METHODS

Between 1999 and 2004, 1252 patients were randomized to EVAR or open repair in the UK EVAR trial 1. All patients were followed for death, myocardial infarction or stroke until September 2009. Cox regression was used to compare cardiovascular events and deaths between the randomized groups during different time intervals.

RESULTS

Over 5 years of follow-up, a total of 187 first non-fatal or fatal cardiovascular events (98 myocardial infarctions and 89 strokes) and 256 cardiovascular deaths occurred. Although the endovascular group had a lower cardiovascular event rate than the open repair group (2·6 versus 3·2 per 100 person-years respectively) this was not statistically significant (adjusted hazard ratio (HR) 0·83, 95 per cent confidence interval 0·62 to 1·10; P = 0·199). Overall, there was little difference in cardiovascular mortality between the randomized groups (adjusted HR 1·06, 0·83 to 1·36; P = 0·638), but a non-significant excess of cardiovascular deaths was apparent in the endovascular group during the 6-24-month interval (adjusted HR 1·44, 0·79 to 2·62; P = 0·237).

CONCLUSION

Patients who had EVAR appeared to have a lower subsequent cardiovascular event rate during all time intervals. Cardiovascular mortality was similar between the two groups overall, but more cardiovascular deaths in the EVAR group appeared to contribute to the convergence in all-cause mortality during the first 2 years.

Systematic review and meta-analysis of growth rates of small abdominal aortic aneurysms

BACKGROUND

Small abdominal aortic aneurysms are usually asymptomatic and managed safely in ultrasound surveillance programmes until they grow to a diameter threshold where intervention is considered. The aim of this study was to synthesize systematically the published data on growth rates for small aneurysms to investigate the evidence basis for surveillance intervals.

METHODS

This was a systematic review of the literature published before January 2010, which identified 61 potentially eligible reports. Detailed review yielded 15 studies providing growth rates for aneurysms 3·0-5·5 cm in diameter (14 in millimetres per year, 1 as percentage change per year). These studies included 7630 people (predominantly men) enrolled during 1976-2005.

RESULTS

The pooled mean growth rate was 2·32 (95 per cent confidence interval 1·95 to 2·70) mm/year but there was very high heterogeneity between studies; the growth rate ranged from - 0·33 to + 3·95 mm/year. Six studies reported growth rates by 5-mm diameter bands, which showed the trend for growth rate to increase with aneurysm diameter. Simple methods to determine growth rate were associated with higher estimates. Meta-regression analysis showed that a 10-mm increase in aneurysm diameter was associated with a mean(s.e.m.) 1·62(0·20) mm/year increase in growth rate. Neither mean age nor percentage of women in each study had a significant effect. On average, a 3·5-cm aneurysm would take 6·2 years to reach 5·5 cm, whereas a 4·5-cm aneurysm would take only 2·3 years.

CONCLUSION

There was considerable variation in the reported growth rates of small aneurysms beyond that explained by aneurysm diameter. Fuller evidence on which to base surveillance intervals for patients in screening programmes requires a meta-analysis based on individual patient data.

An accelerated Ponseti versus the standard Ponseti method

We conducted a prospective randomised controlled trial to compare the standard Ponseti plaster method with an accelerated method for the treatment of idiopathic congenital talipes equinovarus. The standard weekly plaster-change method was accelerated to three times per week. We hypothesised that both methods would be equally effective in achieving correction. A total of 40 consecutive patients (61 feet) were entered into the trial. The initial median Pirani score was 5.5 (95% confidence interval 4.5 to 6.0) in the accelerated group and 5.0 (95% confidence interval 4.0 to 5.0) in the standard control group. The scores decreased by an average 4.5 in the accelerated group and 4.0 in the control group. There was no significant difference in the final Pirani score between the two groups (chi-squared test, p = 0.308). The median number of treatment days in plaster was 16 in the accelerated group and 42 in the control group (p < 0.001). Of the 19 patients in the accelerated group, three required plaster treatment for more than 21 days and were then assigned to the standard control method. Of the 40 patients, 36 were followed for a minimum of six months.

These results suggest that comparable outcomes can be achieved with an accelerated Ponseti method. The ability to complete all necessary manipulations within a three-week period facilitates treatment where patients have to travel long distances.

Rupture rates of small abdominal aortic aneurysms: a systematic review of the literature

BACKGROUND

Small aneurysms of the abdominal aorta (3.0-5.5 cm in diameter) often are managed by regular surveillance, rather than surgery, because the risk of surgery is considered to outweigh the risk of aneurysm rupture. The risk of small aneurysm rupture is considered to be low. The purpose of this review is to summarise the reported estimates of small aneurysm rupture rates.

METHODS AND FINDINGS

We conducted a systematic review of the literature published before 2010 and identified 54 potentially eligible reports. Detailed review of these studies showed that both ascertainment of rupture, patient follow-up and causes of death were poorly reported: diagnostic criteria for rupture were never reported. There were only 14 studies from which rupture rates (as ruptures per 100 person-years) were available. These 14 published studies included 9779 patients (89% male) over the time period 1976-2006 but only 7 of these studies provided rupture rates specifically for the diameter range 3.0-5.5 cm, which ranged from 0 to 1.61 ruptures per 100 person-years.

CONCLUSIONS

Rupture rates of small abdominal aortic aneurysms would appear to be low, but most studies have been poorly reported and did not have clear ascertainment and diagnostic criteria for aneurysm rupture.

Use of baseline factors to predict complications and reinterventions after endovascular repair of abdominal aortic aneurysm

BACKGROUND

It is uncertain which baseline factors are associated with graft-related complications and reinterventions after endovascular aneurysm repair (EVAR) in patients with a large abdominal aortic aneurysm.

METHODS

Patients randomized to elective EVAR in EVAR Trial 1 or 2 were followed for serious graft-related complications (type 2 endoleaks excluded) and reinterventions. Cox regression analysis was used to investigate whether any prespecified baseline factors were associated with time to first serious complication or reintervention.

RESULTS

A total of 756 patients who had elective EVAR were followed for a mean of 3.7 years, by which time there were 179 serious graft complications (rate 6.5 per 100 person years) and 114 reinterventions (rate 3.8 per 100 person years). The highest rate was during the first 6 months, with an apparent increase again after 2 years. Multivariable analysis indicated that graft-related complications increased significantly with larger initial aneurysm diameter (P < 0.001) and older age (P = 0.040). There was also evidence that patients with larger common iliac diameters experienced higher complication rates (P = 0.011).

CONCLUSION

Graft-related complication and reintervention rates were common after EVAR in patients with a large aneurysm. Younger patients and those with aneurysms closer to the 5.5-cm threshold for intervention experienced lower rates.

Randomized clinical trial of VNUS® ClosureFAST™ radiofrequency ablation versus laser for varicose veins

Background

Endovenous laser ablation (EVLA) and radiofrequency ablation (RFA) are both associated with excellent technical, clinical and patient-reported outcomes for the treatment of varicose veins. The aim of this study was to compare the techniques in a randomized clinical trial.

Methods

Consecutive patients with primary great saphenous vein reflux were randomized to EVLA (980 nm) or RFA (VNUS® ClosureFAST™) at a single centre. The primary outcome measure was postprocedural pain after 3 days. Secondary outcome measures were quality of life at 6 weeks, determined by the Aberdeen Varicose Vein Questionnaire (AVVQ) and Short Form 12 (SF-12®), and clinical improvement assessed by the Venous Clinical Severity Score (VCSS). Analyses were performed on the basis of intention to treat using multivariable linear regression.

Results

Some 131 patients were randomized to EVLA (64 patients) or RFA (67). Mean(s.d.) pain scores over 3 days were 26·4(22·1) mm for RFA and 36·8(22·5) mm for EVLA (P = 0·010). Over 10 days, mean(s.d.) pain scores were 22·0(19·8) mm versus 34·3(21·1) mm for RFA and EVLA respectively (P = 0·001). The mean(s.d.) number of analgesic tablets used was lower for RFA than for EVLA over 3 days (8·8(9·5) versus 14·2(10·7); P = 0·003) and 10 days (20·4(22·6) versus 35·9(29·4) respectively; P = 0·001). Changes in AVVQ, SF-12® and VCSS scores at 6 weeks were similar in the two groups: AVVQ (P = 0·887), VCSS (P = 0·993), SF-12® physical component score (P = 0·276) and mental component score (P = 0·449).

Conclusion

RFA using VNUS® ClosureFAST™ was associated with less postprocedural pain than EVLA. However, clinical and quality-of-life improvements were similar after 6 weeks for the two treatments. Registration number: ISRCTN66818013 (http://www.controlled-trials.com).

Effluent carbonaceous biochemical oxygen demand (CBOD) characterization for modern pulp and paper facilities

As receiving water quality models are being used to address dissolved oxygen issues requiring an increased degree of resolution, a more refined characterization of effluent CBOD can become an important aspect of the analysis. The selection and use of kinetic models to identify effluent specific parameters can have a significant impact on this characterization. This study modeled effluents from six pulp and paper facilities in order to reassess the kinetic models, the data, and experimental design used for a typical effluent characterization. The dual first order model fit these effluents with significantly less error than the traditional first order model suggesting a significant fraction of the CBOD is slowly degradable. Because the dual first order model produces a more refined characterization of CBOD kinetics than the first order model, it places an increased demand upon the data used to inform the parameter estimates. Therefore, analysis of the precision of the parameter estimates and methods for improving estimation precision via experimental design are also discussed.

The surgical management of 73 vascular malformations and preoperative predictive factors of major haemorrhage--a single centre experience

OBJECTIVES

In our series of patients with congenital vascular malformations (CVMs) we investigate the preoperative factors for predicting major haemorrhage at surgery and propose an algorithm for their surgical management.

DESIGN

This is a partly prospective case series of patients with severe symptoms/complications due to CVMs.

MATERIALS AND METHODS

Data were collected on 73 consecutive procedures in 41 patients with CVMs from 1992 to 2006 at a large university hospital and the association of following factors with blood loss during the procedure were investigated: type of procedure, possibility of proximal tourniquet use, lesion flow characteristics, previous history of major haemorrhage with CVM surgery, platelet counts and length of hospital stay.

RESULTS

Significantly higher blood loss was associated with debulking surgery (p=0.006) and with previous history of major haemorrhage during CVM surgery, (p=0.041). Blood loss was higher in lesions where proximal tourniquet application was not possible (p=0.093). High-flow lesions were not strongly associated with major blood loss (p=0.288). Major blood loss (>2l) occurred in 16 (20.8%) procedures performed on 11 (26.2%) patients, but this did not prolong hospital stay.

CONCLUSION

Surgery can potentially improve morbidity/mortality in patients with life/limb-threatening complications or severe symptoms due to CVMs, providing they are managed in multidisciplinary specialised centres.

The outcome of spinal decompression surgery 5 years on

Decompression surgery is an increasingly common operation for the treatment of lumbar spinal stenosis. Although good relief from leg pain is expected after surgery, long term results of pain relief and function are more uncertain. This study prospectively followed a cohort of patients presenting with the signs and symptoms of spinal stenosis, who underwent decompression surgery to ascertain the long term outcome with respect to pain and function using visual analogue pain scores, the Oswestry Disability Index, and the Short Form 36, a general health questionnaire. From an initial pool of 84 recruited patients, 7 withdrew from surgical intervention; of the remaining 77, 51 (66%) returned for follow up assessments at 5 years. In these responders, a significant improvement was observed in back and leg pain, which was sustained for at least 1 year (P < 0.01). A significant improvement was also seen in physical function (P < 0.05) as assessed by Oswestry and SF-36. Although an initial improvement was noted in social function, this was not observed at 5 years. This study has demonstrated that decompression surgery is successful in relieving symptoms of lumbar spinal stenosis. Physical function, back and leg pain are significantly improved after 5 years but initial significant improvements in social function diminish over time.

Modelling the long-term cost-effectiveness of endovascular or open repair for abdominal aortic aneurysm

Background

Recent randomized trials have shown that endovascular abdominal aortic aneurysm repair (EVAR) has a 3 per cent aneurysm-related survival benefit in patients fit for open surgery, but it also has uncertain long-term outcomes and higher costs. This study assessed the cost-effectiveness of EVAR.

Methods

A decision model was constructed to estimate the lifetime costs and quality-adjusted life years (QALYs) with EVAR and open repair in men aged 74 years. The model includes the risks of death from aneurysm, other cardiovascular and non-cardiovascular causes, secondary reinterventions and non-fatal cardiovascular events. Data were taken largely from the EVAR trial 1 and supplemented from other sources.

Results

Under the base-case (primary) assumptions, EVAR cost £3800 (95 per cent confidence interval (c.i.) £2400 to £5200) more per patient than open repair but produced fewer lifetime QALYs (mean − 0·020 (95 per cent c.i. − 0·189 to 0·165)). These results were sensitive to alternative model assumptions.

Conclusion

EVAR is unlikely to be cost-effective on the basis of existing devices, costs and evidence, but there remains considerable uncertainty.

Secondary Interventions and Mortality Following Endovascular Aortic Aneurysm Repair: Device-specific Results from the UK EVAR Trials

OBJECTIVES

To compare secondary intervention rate, aneurysm-related mortality and all-cause mortality for patients receiving elective endovascular aneurysm repair (EVAR) for large abdominal aortic aneurysms with different commercially available endografts.

DESIGN, MATERIALS & METHODS

In the EVAR 1 and 2 multi-centre trials, the principal endografts used were Zenith and Talent and these are compared in 505 patients from EVAR 1 and 143 patients from EVAR 2 followed-up for an average of 3.8 years until 31st December 2005. Outcomes were analysed by Cox proportional hazards regression, with adjustments for potential confounding risk factors and centre. Gore/Excluder graft outcomes also are reported.

RESULTS

Across the two trials the secondary intervention rates were 7.0 and 9.4 per 100 patient years for Zenith and Talent grafts respectively, adjusted hazard ratio 0.77 [95%CI 0.52-1.12]. Aneurysm-related mortality was 1.2 and 1.4 per 100 patient years for Zenith and Talent grafts respectively, adjusted hazard ratio 0.90 [95%CI 0.37-2.19]. All-cause mortality was 8.5 and 10.3 per 100 patient years for Zenith and Talent grafts respectively, adjusted hazard ratio 0.81 [95%CI 0.58-1.14]. The direction of all results was similar when the two trials were analysed separately.

CONCLUSION

There was no significant difference in the performance of the two endografts but the direction of results was slightly in favour of patients with Zenith (versus Talent) endografts.

Patient fitness and survival after abdominal aortic aneurysm repair in patients from the UK EVAR trials

Background

The aim was to use a validated fitness score to determine whether fitter patients with a large abdominal aortic aneurysm (AAA) benefited from having open rather than endovascular repair.

Methods

The Customized Probability Index (CPI) was applied to patients in the Endovascular Aneurysm Repair (EVAR) I and II trials. Interaction tests between CPI and randomized group assessed the effect of fitness and type of AAA repair on elective 30-day mortality and 4-year survival.

Results

The mean(s.d.) CPI scores were 3·6(9·3) for 1252 EVAR I patients and 10·0(11·3) for 404 EVAR II patients (range − 25 to + 43) (P &lt; 0·001). The fitness of EVAR I patients was classified as good (579 patients, mean CPI − 4·2), moderate (331 patients, mean CPI 5·7) or poor (338 patients, mean CPI 15·1). Only in the good fitness group did 30-day mortality convincingly favour endovascular repair (odds ratio 0·24, P = 0·030), but overall the test of interaction was not significant (P = 0·363). For 4-year all-cause and aneurysm-related mortality, there was no benefit for either treatment across all fitness scores (P = 0·281 and P = 0·371 respectively).

Conclusion

The benefit of endovascular repair was most convincing in the fittest patients. There was no evidence that the fittest patients benefited more from open surgery.

Final 12-year follow-up of Surgery versus Surveillance in the UK Small Aneurysm Trial

Background

The aim was to determine whether early open surgical repair would benefit patients with small abdominal aortic aneurysm compared with surveillance on long-term follow-up.

Methods

The 1090 patients who were enrolled into the UK Small Aneurysm Trial between 1991 and 1995 were followed up for aneurysm repair and mortality until November 2005.

Results

By November 2005, 714 patients (65·5 per cent) had died, 929 (85·2 per cent) had undergone aneurysm repair, 150 (13·8 per cent) had died without aneurysm repair and 11 (1·0 per cent) remained alive without aneurysm repair. After 12 years, mortality in the surgery and surveillance groups was 63·9 and 67·3 per cent respectively, unadjusted hazard ratio 0·90 (P = 0·139). Three-quarters of the surveillance group eventually had aneurysm repair, with a 30-day elective mortality of 6·3 per cent (versus 5·0 per cent in the early surgery group, P = 0·366). Estimates suggested that the cost of treatment was 17 per cent higher in the early surgery group, with a mean difference of £1326. The death rate in these patients was about twice that in the population matched for age and sex.

Conclusion

There was no long-term survival benefit of early elective open repair of small abdominal aortic aneurysms. Even after successful aneurysm repair, the mortality among these patients was higher than in the general population.

Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial

BACKGROUND

Endovascular aneurysm repair (EVAR) is a new technology to treat patients with abdominal aortic aneurysm (AAA) when the anatomy is suitable. Uncertainty exists about how endovascular repair compares with conventional open surgery. EVAR trial 1 was instigated to compare these treatments in patients judged fit for open AAA repair.

METHODS

Between 1999 and 2003, 1082 elective (non-emergency) patients were randomised to receive either EVAR (n=543) or open AAA repair (n=539). Patients aged at least 60 years with aneurysms of diameter 5.5 cm or more, who were fit enough for open surgical repair (anaesthetically and medically well enough for the procedure), were recruited for the study at 41 British hospitals proficient in the EVAR technique. The primary outcome measure is all-cause mortality and these results will be released in 2005. The primary analysis presented here is operative mortality by intention to treat and a secondary analysis was done in per-protocol patients.

FINDINGS

Patients (983 men, 99 women) had a mean age of 74 years (SD 6) and mean AAA diameter of 6.5 cm (SD 1). 1047 (97%) patients underwent AAA repair and 1008 (93%) received their allocated treatment. 30-day mortality in the EVAR group was 1.7% (9/531) versus 4.7% (24/516) in the open repair group (odds ratio 0.35 [95% CI 0.16-0.77], p=0.009). By per-protocol analysis, 30-day mortality for EVAR was 1.6% (8/512) versus 4.6% (23/496) for open repair (0.33 [0.15-0.74], p=0.007). Secondary interventions were more common in patients allocated EVAR (9.8% vs 5.8%, p=0.02).

INTERPRETATION

In patients with large AAAs, treatment by EVAR reduced the 30-day operative mortality by two-thirds compared with open repair. Any change in clinical practice should await durability and longer term results.

The UK Endovascular Aneurysm Repair (EVAR) Trials: Design, Methodology and Progress

OBJECTIVES

The endovascular aneurysm repair (EVAR) trials aim to assess the efficacy of EVAR in the treatment of AAA in terms of mortality, quality of life, durability and cost-effectiveness.

DESIGN

Male and female patients aged at least 60 years with an AAA diameter measuring at least 5.5 cm on a computed tomography (CT) scan are assessed for anatomical suitability for EVAR. Suitable patients are offered entry either into EVAR Trial 1 if they are considered fit for conventional open repair or EVAR Trial 2 if they are considered unfit. EVAR 1 randomly allocates patients to EVAR or open repair and EVAR 2 randomly allocates patients to EVAR with best medical treatment or best medical treatment alone. Target recruitment for EVAR Trials 1 and 2 is 900 and 280 patients, respectively.

PROGRESS

Recruitment began in September 1999 and there are currently 40 UK centres participating in the trials. Monthly targets are being exceeded in EVAR Trial 1 with 1037 patients randomised by October 2003. EVAR Trial 2 is also meeting monthly targets with a total of 319 patients randomised. When recruitment closes in December 2003 patients will need to be followed for at least 1 year from their operation. Publication of full results for both trials is expected in mid 2005.

Genetic approach to the role of cysteine proteases in the expansion of abdominal aortic aneurysms

Background

The elastinolytic cysteine proteases, including cathepsins S and K, are overexpressed at sites of arterial elastin damage. Cystatin C, an inhibitor of these enzymes, is expressed in arterial smooth muscle cells; an imbalance in cystatin C has been implicated in the aortic wall degeneration observed in abdominal aortic aneurysms (AAAs). The aim of the study was to investigate the impact of a polymorphism in the signal peptide of the cystatin C gene on the growth of small AAAs.

Methods

Some 424 patients with a small AAA (4·0–5·5 cm) were monitored for AAA growth by ultrasonography and provided a DNA sample for analysis of the + 148 G &gt; A polymorphism in the cystatin C signal peptide and the—82 G &gt; C polymorphism in the gene promoter. The median length of follow-up was 2·8 years and AAA growth rates were calculated by linear regression analysis.

Results

For patients of + 148 GG (n = 263), GA (n = 147) and AA (n = 20) genotypes, the mean(s.d.) AAA growth rates were 0·37(0·29), 0·37(0·23) and 0·30(0·26) cm, and initial diameters were 4·58(0·35), 4·58(0·35) and 4·62(0·36) cm, respectively. Patients of + 148 AA genotype had a slower aneurysm growth rate (unadjusted P = 0·058; after adjustment for age, sex, initial AAA diameter and smoking, P = 0·027). There also was a trend for the rare homozygotes of the—82 C allele to have slower AAA growth (adjusted P = 0·055). Smoking history had a stronger association with aneurysm growth (P = 0·003).

Conclusion

There was a weak association between variation in the cystatin C gene and AAA growth. Medical strategies to limit AAA growth might include the inhibition of cysteine proteases.

Interleukin 6 and the prognosis of abdominal aortic aneurysms

Background

Abdominal aortic aneurysm (AAA) is a familial disorder, inflammation being an important pathophysiological feature. Increased plasma concentrations of the inflammatory cytokine interleukin (IL) 6 have been associated with AAA and early aortic dilatation. This study was designed to test the hypothesis that high concentrations of plasma IL-6 and/or IL-6 genotype predict rapid AAA growth.

Methods

Genomic DNA from 466 patients, kept under ultrasonographic surveillance for small AAAs, was analysed for a G to C polymorphism at position −174 of the IL-6 promoter. Baseline plasma IL-6 concentration was measured by enzyme-linked immunosorbent assay and AAA growth rates were calculated by linear regression.

Results

The median concentration of plasma IL-6 was 4·9 (range 0–604) pg ml−1. IL-6 concentration was not associated with aneurysm growth rate. The frequency of the C allele was 0·40, similar to that in the healthy population. Patients of GG genotype had a lower plasma concentration of IL-6 than patients of either GC or CC genotype (median 1·9, 4·8 and 15·6 pg ml−1 respectively; P = 0·047, Kruskal–Wallis test). The AAA growth rate for patients of GG, GC and CC genotypes was 0·38, 0·36 and 0·36 cm per year respectively (P = 0·37). Mortality was lower for patients of GG genotype than for those with GC or CC genotype: hazard ratio 0·51 (95 per cent confidence interval (c.i.) 0·25–1·00), P = 0·05; and 0·32 (95 per cent c.i. 0·12–0·93), P = 0·036, for all-cause and cardiovascular mortality respectively.

Conclusion

Genetic polymorphism is associated with clinical events in patients with an AAA. The G to C IL-6 polymorphism at position −174 predicts future cardiovascular mortality. Neither plasma IL-6 concentration nor IL-6 genotype predicts AAA growth.

Risk factors for aneurysm rupture: results from the UK small aneurysm study and trial

Background

The UK Small Aneurysm Trial has shown that ultrasonographic surveillance is a safe management option for patients with small abdominal aortic aneurysms (4·0–5·5 cm in diameter), with an annual rupture rate of 1 per cent. In this study risk factors associated with aneurysm rupture have been investigated using both patients randomized into the UK Small Aneurysm Trial and those monitored for aneurysm growth in the associated study.

Methods

The cohort of patients included 1090 from the trial and 1167 from the associated study. In this cohort of 2257 patients (79 per cent men), aged 59–77 years, 103 instances of abdominal aortic aneurysm rupture were identified during the 7-year follow-up (1991–1998). The relationship between rupture and ten prespecified risk factors (including age, sex, aneurysm diameter, smoking status, plasma cholesterol, lung function and ankle: brachial pressure index) was investigated using Kaplan–Meier survival and Cox regression analysis.

Results

Almost all patients (98 per cent) had initial aneurysm diameters in the range 3–6 cm and the majority of ruptures (76 per cent) occurred in patients with aneurysms known to be larger than 5 cm in diameter. Kaplan–Meier survival and Cox regression analysis were used to identify baseline risk factors associated with aneurysm rupture. After 3 years, the annual rate of aneurysm rupture was 2·2 (95 per cent confidence interval 1·7–2·8) per cent. The risk of rupture was independently and significantly associated with female sex (P &lt; 0·001), larger initial aneurysm diameter (P &lt; 0·001), lower FEV1 (P = 0·004), current smoking (P = 0·01) and higher mean blood pressure (P = 0·01). Age, body mass index, serum cholesterol concentration and ankle: brachial pressure index were not associated with an increased risk of aneurysm rupture.

Conclusion

Within this cohort of patients women had a threefold higher risk of aneurysm rupture than men. Effective control of blood pressure and cessation of smoking are likely to diminish the risk of rupture.

Long-term outcomes of immediate repair compared with surveillance of small abdominal aortic aneurysms

BACKGROUND

Two clinical trials, one British and one American, have shown that early, prophylactic elective surgery does not improve five-year survival among patients with small abdominal aortic aneurysms. We report long-term outcomes in the United Kingdom Small Aneurysm Trial.

METHODS

We randomly assigned 1090 patients, 60 to 76 years of age, with small abdominal aortic aneurysms (diameter, 4.0 to 5.5 cm) to one of two groups: 563 were assigned to undergo early elective surgery, and 527 were assigned to undergo surveillance by ultrasonography. Patients were followed in the trial until June 1998 and thereafter until August 2001; the mean duration of follow-up was 8 years (range, 6 to 10).

RESULTS

The mean duration of survival was 6.5 years among patients in the surveillance group, as compared with 6.7 years among patients in the early-surgery group (P=0.29). The adjusted hazard ratio for death from any cause in the early-surgery group as compared with the surveillance group was 0.83 (95 percent confidence interval, 0.69 to 1.00; P=0.05). The 30-day operative mortality in the early-surgery group (5.5 percent) led to an early disadvantage in terms of survival. The survival curves crossed at three years, and at eight years, mortality in the early-surgery group was 7.2 percentage points lower than that in the surveillance group (P=0.03). There was no evidence that age, sex, or the initial size of the aneurysm modified the hazard ratio or that delayed surgery in the surveillance group increased 30-day postoperative mortality. Death was attributable to a ruptured aneurysm in 19 of the 411 men who died (5 percent) and in 12 of the 85 women who died (14 percent) (P=0.001). The rate of early cessation of smoking was higher in the early-surgery group than in the surveillance group.

CONCLUSIONS

Among patients with a small abdominal aortic aneurysm, we found no long-term difference in mean survival between the early-surgery and surveillance groups, although after eight years, total mortality was lower in the early-surgery group. This difference may be attributed in part to beneficial changes in lifestyle adopted by members of the early-surgery group.

Interleukin-6 (IL-6) and the prognosis of abdominal aortic aneurysms

BACKGROUND

Abdominal aortic aneurysm is a multifactorial disorder in which inflammation is an important pathophysiological feature. In explant culture, aneurysm biopsies secrete large amounts of interleukin-6 (IL-6), and among aneurysm patients, the circulating concentration of IL-6 appears to be increased.

METHODS AND RESULTS

We investigated, in 19 patients, whether aneurysm wall was an important source of circulating IL-6. We also tested the hypotheses, in 466 patients with a small aneurysm, that (1) high concentrations of circulating IL-6 signaled rapid aneurysm growth and (2) the -174 G-->C polymorphism in the IL-6 promoter predicted survival. For 19 patients with large or inflammatory aneurysms, the concentration of IL-6 was higher in the iliac arteries than the brachial arteries (median difference 26.5 pg/mL, this difference increasing with aneurysm diameter, P=0.01). In 466 patients with small aneurysms, the frequency of the -174 C allele (0.40) was similar to that in a normal healthy population. Patients of GG genotype had lower plasma concentrations of IL-6 than patients of GC and CC genotypes (medians 1.9, 4.8, and 15.6 pg/mL, respectively, Kruskal-Wallis P=0.047). Cardiovascular and all-cause mortalities were lower for patients of GG genotype than for patients of GC and CC genotype: hazard ratios 0.32 (95% CI 0.12 to 0.93), P=0.036, and 0.51 (95% CI 0.25 to 1.00), P=0.05, respectively. There was no association between plasma IL-6 or IL-6 genotype and aneurysm growth.

CONCLUSIONS

Aortic aneurysms appear to be an important source of circulating IL-6, the concentration being influenced by genotype. For patients with small aneurysms, the -174 G-->C IL-6 genotype predicts future cardiovascular mortality.

The natural history of abdominal aortic aneurysms and their risk of rupture

The UK Small Aneurysm Trial has shown that ultrasound surveillance is a safe management option for patients with small abdominal aortic aneurysms (4.0 to 5.5 cm in diameter), with an annual rupture rate of only 1%. We investigated baseline risk factors associated with aneurysm rupture in the 1090 trial patients and an additional 1167 patients enrolled in the UK Small Aneurysm Study. In this cohort of 2257 patients there were 103 cases of aneurysm rupture. After 3 years the annual rate of rupture was 2.2% (95% CI 1.7 to 2.8). The risk of rupture was independently and significantly associated with female sex (p < 0.001), larger initial aneurysm diameter (p < 0.001), current smoking (p = 0.01) and higher mean blood pressure (p = 0.01). Age, body mass index, serum cholesterol concentration and ankle/brachial pressure index were not associated with an increased risk of aneurysm rupture. The most surprising finding was that women had a 3-fold higher risk of aneurysm rupture than men. Effective control of blood pressure and cessation of smoking are two simple measures that are likely to diminish the risk of aneurysm rupture and improve the cardiovascular health of patients with abdominal aortic aneurysm.

Percutaneous fibrin sheath stripping versus transcatheter urokinase infusion for malfunctioning well-positioned tunneled central venous dialysis catheters: a prospective, randomized trial

PURPOSE

To compare central dialysis catheter patency rates after stripping procedures with those after urokinase (UK) infusion.

MATERIALS AND METHODS

Fifty-seven tunneled catheters with either (i) flow rates less than 250 mL/min and established baseline flow rates > or = 300 mL/min or (ii) flow rates 50 mL/min less than higher established baseline flows were prospectively randomized to undergo stripping procedures (n = 28) or UK infusion (n = 29) at 30,000 U/h via each port concurrently, for a total 250,000 U. Success and patency were determined by dialysis at normal flow rates (> or = 300 mL/min) or at the previously established higher baseline rate. Flow rates were monitored weekly. Primary patency ended with catheter malfunction or removal. Kaplan-Meier survival analysis was used to construct survival curves.

RESULTS

In the stripping group, initial clinical success was 89% (25 of 28). The 15-, 30-, and 45-day primary patency rates were 75% (n = 20), 52% (n = 13), and 35% (n = 8), respectively. The median duration of additional function was 32 days (95% CI: 18-48 d). In the UK group, initial clinical success was 97% (28 of 29). The 15-, 30-, and 45-day primary patency rates were 86% (n = 21), 63% (n = 13), and 48% (n = 9), respectively. The median duration of additional patency was 42 days (95% CI: 22-153 d). The Wilcoxon test for equality detected no significant difference in the survival curves for the two treatment groups (P = .236).

CONCLUSION

There is no significant difference in time to primary patency between the two methods. Both allow temporary catheter salvage in most patients.

Descriptive epidemiology of de novo acute leukaemia in the Sultanate of Oman

A hospital-based epidemiological study of de novo acute leukaemia was carried out in the Sultanate of Oman, a sparsely populated Arabian Gulf country which has undergone rapid and dramatic socio-economic changes recently. A total of 65/99 Omanis (66%) were diagnosed as acute lymphoblastic leukaemia (ALL) and 34/99 (34%) as acute myeloid leukaemia (AML). Trends and peak values in age-specific incidence rates for ALL are generally in line with those of Western countries. The proportion of T-ALL cases is however higher than that in Caucasian populations but lower than in many non-white populations. AML frequency particularly in childhood is similar to that observed in many African countries.

Et Tu, Counselor: may an in-house attorney file a qui tam action against the attorney's employer?

Most corporations probably do not consider their in-house counsel to be potential qui tam threats. That may be a naive assumption. Case law provides an illustrative view of the legal ramifications involved when an attorney brings a qui tam suit. In general, there is no prohibition on attorneys who wish to bring these actions. Nevertheless, a corporation can take preventive steps to eliminate the likelihood of attorney qui tam actions. In addition, the corporation can take advantage of state professional ethics laws to mount a defensive action against the attorney who files any such action.

Risk factors for aneurysm rupture in patients kept under ultrasound surveillance. UK Small Aneurysm Trial Participants

OBJECTIVE

To investigate risk factors associated with aneurysm rupture using patients randomized into the U.K. Small Aneurysm Trial (n = 1090) or monitored for aneurysm growth in the associated study (n = 1167).

SUMMARY BACKGROUND DATA

The U.K. Small Aneurysm Trial has shown that ultrasound surveillance is a safe management option for patients with small abdominal aortic aneurysms (4.0 to 5.5 cm in diameter), with an annual rupture rate of 1%.

METHODS

In the cohort of 2257 patients (79% male), aged 59 to 77 years, 103 instances of abdominal aortic aneurysm rupture were identified during the 7-year period of follow-up (1991-1998). Almost all patients (98%) had initial aneurysm diameters in the range of 3 to 6 cm, and the majority of ruptures (76%) occurred in patients with aneurysms > or =5 cm in diameter. Kaplan-Meier survival and Cox regression analysis were used to identify baseline risk factors associated with aneurysm rupture.

RESULTS

After 3 years, the annual rate of aneurysm rupture was 2.2% (95% confidence interval 1.7 to 2.8). The risk of rupture was independently and significantly associated with female sex (p < 0.001), larger initial aneurysm diameter (p < 0.001), lower FEV1 (p = 0.004), current smoking (p = 0.01), and higher mean blood pressure (p = 0.01). Age, body mass index, serum cholesterol concentration, and ankle/brachial pressure index were not associated with an increased risk of aneurysm rupture.

CONCLUSIONS

Within this cohort of patients, women had a threefold higher risk of aneurysm rupture than men. Effective control of blood pressure and cessation of smoking are likely to diminish the risk of rupture.

Inhibition of prostaglandin E2 synthesis in abdominal aortic aneurysms: implications for smooth muscle cell viability, inflammatory processes, and the expansion of abdominal aortic aneurysms

BACKGROUND

There is no treatment proven to limit the growth of abdominal aortic aneurysms, in which the histological hallmarks include inflammation and medial atrophy, with apoptosis of smooth muscle cells and destruction of elastin.

METHODS AND RESULTS

Aneurysm biopsies were used for explant cultures, the preparation of smooth muscle cell cultures, and isolation of macrophages. Tissue macrophages stained strongly for cyclooxygenase 2. Prostaglandin E2 (PGE2) concentrations in aneurysm tissue homogenates, conditioned medium from explants, and isolated macrophages were 49+/-22 ng/g, 319+/-38 ng/mL, and 22+/-21 ng/mL, respectively. PGE2 inhibited DNA synthesis and proliferation in normal aortic smooth muscle cells (IC50, 23.2+/-3.8 and 23.6+/-4.5 ng/mL, respectively). In smooth muscle cells derived from aneurysmal aorta, PGE2 also caused cell death, with generation of oligonucleosomes. Conditioned medium from the mixed smooth muscle and monocyte cultures derived from explants also had potent growth-inhibitory effects, and fractionation of this medium showed that the growth-inhibitory molecule(s) coeluted with PGE2. In explants, indomethacin 10 micromol/L or mefenamic acid 10 micromol/L abolished PGE2 secretion and significantly reduced IL-1beta and IL-6 secretion. In a separate case-control study, the expansion of abdominal aortic aneurysms was compared in 15 patients taking nonsteroidal anti-inflammatory drugs and 63 control subjects; median growth rates were 1.5 and 3.2 mm/y, respectively, P=0.001.

CONCLUSIONS

The adverse effects of PGE2 on aortic smooth muscle cell viability and cytokine secretion in vitro and the apparent effect of anti-inflammatory drugs to lower aneurysm growth rates suggest that selective inhibition of PGE2 synthesis could be an effective treatment to curtail aneurysm expansion.