Biomedical subjects

James B Semmens

Publications and source records attributed to James B Semmens.

At least 19 recordsLinked to original sources

PubMed2006

Length of comorbidity lookback period affected regression model performance of administrative health data.

BACKGROUND AND OBJECTIVE: The impact of different comorbidity ascertainment lookback periods on modeling posthospitalization mortality and readmission was examined. METHODS: Index cases comprised medical (n = 326,456) and procedural (n = 349,686) patients with a hospital admission from 1990-1996. Administrative hospital data were extracted for 102 comorbidities, ascertained at index admission and for 1-, 2-, 3-, and 5-year lookback periods. Deaths and readmissions were identified within 12 months and 30 days of separation, respectively. Hierarchically nested and nonnested Cox regressions as well as Receiver Operator Characteristic Area Under the Curve (ROC-AUC) were used to determine model-fit and predictive ability of lookback period models. RESULTS: The 1-year lookback period provided the best model-fit for both patient groups when modeling mortality. A similar model-fit was seen at index admission for procedural but not medical patients. The superior readmission model employed 5 years of lookback for both patient groups. With one exception, all lookback period models were superior to those abstracting comorbidity from index admission only. Similar results were evident from ROC-AUC, although greater predictive ability was seen with modeling of mortality (0.847-0.923) compared with readmission (0.593-0.681). CONCLUSION: The explanatory power of regression models, when adjusting for comorbidity, is influenced by length of lookback, outcome investigated and clinical subgroup. Shorter periods (approximately 1 year) appear appropriate for modeling posthospitalization mortality, whereas longer lookback periods are superior for readmission outcomes.

Cohort Studies↗

PubMed2006

Decreasing rates of middle ear surgery in Western Australian children.

OBJECTIVE: To investigate temporal, social, demographic, and health care utilization factors associated with myringotomy with ventilation tube insertion (MVTI) in Western Australian (WA) children. DESIGN: Observational retrospective population-based cohort study using hospital administrative data. SETTING: All WA hospitals. PARTICIPANTS: A total of 53 673 children younger than 15 years who underwent surgery for MVTI in the period 1981-2004. MAIN OUTCOME MEASURES: Age-specific incidence rates and incidence rate ratios. RESULTS: The rate of MVTI in children younger than 15 years peaked in 1997 at 6.7 per 1000 person-years and decreased to 5.6 per 1000 person-years by 2004. Based on 2004 rates, 8.4% of WA children will undergo at least 1 MVTI procedure before reaching age 15 years. The rate of MVTI was 37% lower in Indigenous children, and the procedures were performed at an older age compared with non-Indigenous children. Higher rates of MVTI were associated with areas of higher economic resources, lower education and occupation status, and living in metropolitan areas. CONCLUSIONS: The rate of MVTI in WA is showing evidence of a decline, even among children younger than 5 years. There remains an issue regarding equity of access to care for Indigenous children. Increasing parental economic resources may be associated with higher rates of MVTI independent of educational status.

Adolescent↗

PubMed2006

Cataract surgery practice and endophthalmitis prevention by Australian and New Zealand ophthalmologists.

PURPOSE: Our aim was to examine current cataract surgery practice and the methods of chemoprophylaxis used in Australia and New Zealand, and to determine if these factors were related to self-reported incidence rates of postoperative endophthalmitis. METHODS: All Fellows and trainees of the Royal Australian and New Zealand College of Ophthalmologists were surveyed about their cataract surgery practices and methods of chemoprophylaxis for the prevention of postoperative endophthalmitis. Associations between self-reported incidence rates of endophthalmitis and clinical practice were examined using multivariate Poisson regression modelling. RESULTS: There were 731 respondents (81.6% of 896 surveyed) to the survey. Respondents reported a total of 162,120 cataract operations and 92 cases of endophthalmitis in 2003, a cumulative incidence of 0.057%. The self-reported incidence of endophthalmitis varied from 0.034% in Victoria to 0.56% in the Northern Territory. Topical antibiotics were used preoperatively by 46.7% compared with 97.4% postoperatively; while only 44.1% used subconjunctival antibiotics. The routine use of subconjunctival antibiotic halved the self-reported incidence of postoperative endophthalmitis (incidence rate ratio 0.53, 95% confidence interval 0.30-0.92). CONCLUSIONS: Subconjunctival antibiotics may be beneficial in the prevention of endophthalmitis after cataract surgery.

Anti-Bacterial Agents↗

PubMed2006

Providers and consumers support the Western Australian Audit of Surgical Mortality.

BACKGROUND: The Western Australian Audit of Surgical Mortality (WAASM) was established in June 2001 to independently peer-review all surgical deaths in Western Australia. The objectives of this study were (i) to evaluate whether participation in the WAASM has influenced clinical and hospital practice; and (ii) to ascertain the support and relevance of the WAASM to surgeons, hospitals and consumers. METHODS: Three qualitative questionnaires were designed to evaluate the response of surgeons, hospital administrators and consumers to the WAASM. The outcomes measured included audit participation, value and use of feedback provided, changes to clinical and hospital practice and the future role of the WAASM. RESULTS: The key findings were that 138 (73%) of 190 surgeons participating in the WAASM had changed their clinical practice in at least one way, 44 (24%) were aware of changes in hospital practice and 21 (11%) were aware of changes in a colleague's practice. Particular areas where changes in surgical practice had occurred included attention to deep vein thrombosis prophylaxis (81, 44%), increased constructive discussion among peers (78, 42%) and quality of documentation in case notes (68, 37%). All groups supported the continuation of the WAASM. Hospital executives and consumers recommended that the WAASM be included in accreditation. CONCLUSION: Surgeons, hospitals and consumers supported the concept of independent peer review of surgical care. They confirmed the ability of audit to influence and change surgical and hospital practice. It strengthens the intention of the Royal Australasian College of Surgeons to extend the WAASM project throughout Australia and New Zealand.

Attitude of Health Personnel↗

PubMed2006

Outcomes of fenestrated endografts in the treatment of abdominal aortic aneurysm in Western Australia (1997-2004).

PURPOSE: To describe a 7-year experience with abdominal aortic aneurysm (AAA) repair using fenestrated Zenith endovascular endografts. METHODS: Six endovascular surgeons from 7 medical centers in Perth, Western Australia, contributed data to this retrospective study of 58 AAA patients (51 men; mean age 75.5+/-8.5 years, range 60-94) treated with fenestrated endografts. Fenestrations were applied to 116 target vessels; more than half of patients had >/=2 target vessels. The results were based on satisfactory deployment of the stent-graft and fenestrations (technical success), technical success and no complications (procedural success), and aneurysm exclusion with no endoleak, rupture, unresolved complications, or dialysis (treatment success). RESULTS: Technical success was 82.8% for patients (90.5% for target vessels), procedural success was 74.1%, and treatment success was 94.8%. There were no cases of conversion or rupture. The 30-day mortality rate was 3.4% (n=2). Over a mean follow-up of 1.4+/-1.2 years, 10 (17.2%) patients experienced loss of a target vessel (9.5% of target vessels). Factors associated with target vessel loss were no stent, >60 degrees neck angulation, multiple renal vessels, and vessel diameter </=4 mm. Four (6.9%) patients developed renal impairment, but none required dialysis. Fourteen (24.1%) patients had a secondary intervention. Unresolved endoleaks persisted in 1 (1.7%) patient. CONCLUSION: Fenestrated endografts extend the treatment options for infrarenal AAAs with necks unsuitable for standard endovascular repair. This early data show a trend toward higher mortality of selected patients with fenestrated endografts than for standard stent-graft repair, but the mortality rate is comparable to open repair. Target vessel occlusion predominantly results from pre-existing disease or the lack of a stent. The lessons learned from this experience contributed toward guidelines for users of fenestrated endografts.

Aged↗

PubMed2006

Movement and dislocation of modular stent-grafts due to pulsatile flow and the pressure difference between the stent-graft and the aneurysm sac.

PURPOSE: To investigate the stability and movement of modular aortic stent-grafts subjected to oscillating forces from pulsatile blood flow, with particular reference to the thoracic aorta. METHODS: Analytical mathematical modeling was used to understand the forces on modular grafts. In a benchtop experiment, a transparent acrylic box was filled with water to mimic an aneurysm. Two stent-grafts were placed inside the box in a nested, arched configuration where one component was partly inside the other. A pump produced a pulsatile approximately 5-L/min flow of water through the stent-grafts at a mean inlet pressure of approximately 100 mmHg (approximately 13,330 Pa), with systolic and diastolic pressures of approximately 130 and approximately 80 mmHg, respectively (pulse pressure 50 mmHg). The movement of the 2 modular stent-grafts was observed. RESULTS: The curved stent-graft system oscillated transversely when there was zero mean pressure difference between the stent-graft and the aneurysm. As the mean pressure difference was increased, this transverse graft movement was damped and then disappeared. A relatively large pressure difference caused the stent-graft to inflate and become sturdier. In terms of stability, the analytical mathematical model for a 30-mm-diameter Zenith modular stent-graft curved through 90 degrees (with the ends of the graft fixed in place) showed that the modular components will separate at a pressure difference of 0 mmHg for 1 stent segment overlap (20 mm) and at an average 59 mmHg pressure difference for 2 stent overlaps, but the device would not separate at a pressure difference of 90 mmHg for 3 stent overlaps. CONCLUSION: Transverse cyclic movement of the curved stent-graft system with pulsation indicates a pressurized sac. When the pressure difference is large and there is a blood-tight seal between the aneurysm and the stent-graft, then the transverse movement of the stent-graft is minimal, but the risk for modular separation is highest. Curved thoracic endografts are subject to forces that may cause migration or separation, the latter being more likely if the seal between the graft and the sac is blood tight, if the blood pressure is high, and if the diameter of the graft is small and the sac large. Operators should plan for maximum overlap of modular components when treating large or long thoracic aneurysms.

Aortic Aneurysm, Thoracic↗

PubMed2006

A laparoscopic access technique for endovascular procedures: surgeon training in an animal model.

PURPOSE: To present a laparoscopic technique for placing a transperitoneal conduit in the common iliac artery (CIA) or distal aorta to circumvent stenosed or occluded iliac systems and to assess the success of this laparoscopic access in a live animal model. TECHNIQUE: A porcine model was used owing to similarities in anatomy and size of the pig aorta to the human common iliac artery (CIA). Ethical approval was obtained, and the technique was developed in 8 animals under general anesthesia. A curved hollow needle, a partially stented Dacron conduit, an airtight laparoscopic port and a sealing sheath and valve were developed specifically for percutaneous access through the abdominal wall. A transperitoneal approach was used to the distal aorta. Cannulation by the curved hollow needle via the new port was under direct vision. The conduit was inserted over a guidewire after needle removal and deployed under fluoroscopy. The distal end of the conduit was secured by the sealing sheath and valve, enabling wire and catheter exchange thereafter. A 2-day educational workshop was held for 12 vascular surgeons with a range of laparoscopic experience. After learning the technique on a simulator model, they worked in pairs, alternating surgeon/assistant roles to insert conduits into 12 animals under general anesthesia. Laparoscopic cannulation in all 12 animals was successful. There was no bleeding around the conduit at the aortic arteriotomy. All animals were euthanized after confirmation of conduit patency by back-bleeding. CONCLUSION: This novel technique bridges the gap between laparoscopic and endovascular techniques in striving for minimally invasive solutions to the treatment of vascular disease. Adaptation to human beings is currently underway and will mean increasing the applicability of endovascular solutions to those patients in whom it would otherwise be denied. The technique would appear not to require specialist laparoscopic skills.

Angioplasty↗

PubMed2006

Short to midterm outcomes of fenestrated endovascular grafts in the treatment of abdominal aortic aneurysms: a systematic review.

PURPOSE: To perform a systematic review of the short to midterm outcomes of fenestrated endovascular grafts in patients with abdominal aortic aneurysms (AAA). METHODS: A search of PubMed and Medline databases for English-language literature was performed to find studies published between 1999 and 2006. Studies investigating the short to midterm results of fenestrated endovascular grafts for AAA were analyzed for clinical outcomes and postprocedural complications. RESULTS: Nineteen studies involving fenestrated endovascular grafting were retrieved, and 6 of them met criteria for inclusion in the analysis. The remaining studies were excluded because they dealt with technical or case reports or cumulative addition of previous cases. Pooled estimates (95% confidence interval) of postprocedural complications were 1.1% (0.4%-2.7%) for 30-day mortality; 8.3% (2.9%-13.6%) for late mortality; 97% (92%-100%) and 90% (85%-95%) for perfusion of fenestrated vessels at perioperative and late follow-up, respectively; 13.3% (4.1%-22.5%) for postprocedural renal dysfunction; and 11.2% (3.2%-22.5%) and 9.4% (2.6%-16.3%) for early and late endoleak, respectively. There was correlation between preoperative renal insufficiency and postprocedural renal dysfunction, although this was not a statistically significant difference (p=0.2). CONCLUSION: Our systematic review showed that fenestrated endovascular grafting provides an alternative technique to treat patients with complex aneurysm necks, achieving lower mortality than open repair under comparable conditions. Preoperative renal impairment is a strong indicator of postoperative renal dysfunction. Long-term stability and patency of the fenestrated vessels deserves to be validated.

Angioplasty, Balloon↗

PubMed2005

The Western Australian Audit of Surgical Mortality: advancing surgical accountability.

OBJECTIVE: To describe the peer review process of the Western Australian Audit of Surgical Mortality (WAASM), selected outcomes and recommendations. STUDY DESIGN: Prospective audit using peer review of all cases of patients who died while under the care of a Western Australian surgeon between 1 January 2002 and 30 June 2004. Audit reviews were current to 30 September 2004. PARTICIPANTS AND SETTING: 194 of 202 surgeons participated after a patient died under their care. MAIN OUTCOME MEASURES: Surgeon participation, deficiencies of care, deep vein thrombosis (DVT) prophylaxis, futile surgery, postmortem reviews, proportion of operations performed by consultant surgeons. RESULTS: The audit process was complete for 896 of 1647 reported deaths (54%), while a further 503 (31%) were still under review at 30 September 2004. Twenty deaths associated with terminal care were excluded from analysis. Median patient age was 80 years, and 799 of the 876 patients who died (91%) had significant comorbidities that increased the risk of death. Deficiencies of care were reported in 179/876 (20%). In 45/876 deaths (5%) the deficiency of care was assessed to have caused the death, and 15 deaths were considered preventable. The risk of a deficiency of care was 1.9 times higher in elective admissions than emergency admissions. Autopsy was undertaken in 83/768 (11%) deaths with complete data. Changes in practice were noted in some areas targeted by WAASM, such as improved DVT prophylaxis. A problem with fluid management was recorded. CONCLUSION: Most patients who died were elderly, had complex comorbidities and were treated appropriately. The WAASM has helped to change surgical practice and emphasises the importance of ongoing systematic audit. The participation of surgeons demonstrates their commitment to accountability and supports the intention of the Royal Australasian College of Surgeons to extend the process throughout Australia and New Zealand.

Adult↗

PubMed2005

Improving the evidence base for promoting quality and equity of surgical care using population-based linkage of administrative health records.

This paper highlights the uses of population-based linkage of administrative health records to improve the quality, safety, and equity of surgical care. The primary focus of the paper is on the transfer of this type of research into policy and practice. In the modern era of evidence-based medicine, it is essential that not only is new evidence incorporated into clinical practice, but that the implementation and associated costs are monitored; this requires the setting of appropriate benchmarking criteria. Furthermore, it is imperative that all members of the population receive optimal health care and people are not discriminated against because of socio-economic, locational, or racial factors. The use of data linkage can assist with examining these aspects of health care and this paper provides real-life examples such as costs and adverse events from laparoscopic cholecystectomy, event monitoring for post-operative venous thrombosis, and inequalities in cancer care. The influence of these studies on clinical practice and policy is also discussed. Furthermore, this paper discusses the strengths and weaknesses of data linkage research and how to avoid pitfalls. Health researchers, clinicians, and policy-makers will find the discussion of these issues useful in their everyday practice.

Ethics, Medical↗

PubMed2005

The Western Australian gestational breast cancer project: a population-based study of the incidence, management and outcomes.

This descriptive population-based study estimates the incidence, and describes the management and outcomes for women diagnosed with gestational breast cancer (GBC) aged 15-44 years in Western Australia between January 1982 and December 2000. Gestational breast cancer accounted for 6.25% of breast cancers in Western Australian women less than 45 years of age, and complicated 23.6 per 100,000 pregnancies. Two thirds were diagnosed postpartum and a third while pregnant. The median time from first symptom to diagnosis was less than four weeks. Women diagnosed during pregnancy were more likely to have a pregnancy termination. Over 50% of women were lymph node positive and those diagnosed postpartum were more likely to have a mastectomy. Five-year survival was better than reported previously (73%). The incidence of GBC was lower than previously reported. Significant differences in pregnancy outcome and management exist between the pregnant and postpartum groups.

Adolescent↗

PubMed2005

A multipurpose comorbidity scoring system performed better than the Charlson index.

BACKGROUND AND OBJECTIVES: To develop a comorbidity scoring system that out-performs the Charlson index. METHODS: Population-based cohorts of medical (n=326,456), procedural (n=349,686), and psychiatric (n=16,895) inpatients in Western Australia were followed for 1-year mortality, 30-day readmissions, and length of stay (LOS) using data linkage. Conditions were identified at index admission and over the preceding 12 months. A Multipurpose Australian Comorbidity Scoring System (MACSS) was developed, based on the most frequent 102 comorbid conditions associated with a rate ratio (RR) > or = 1.1 of death or readmission or a LOS difference > or =0.5 days. The performance of MACSS and the Charlson index in predicting mortality, readmission, and LOS, and in controlling confounding by comorbidity, was compared in five test scenarios involving asthma, myocardial infarction, mastectomy, transurethral prostatectomy, and major depressive illness. RESULTS: MACSS performed better than the Charlson index on all three outcomes in all five clinical groups. It reduced the failure of the Charlson index to discriminate on mortality and readmission outcomes by 5-40%, improved R(2) in LOS models by up to fourfold and often doubled the correction of originally confounded effect measures. CONCLUSION: The use of the MACSS and similar alternatives to the Charlson index are a new methodologic standard for adjustment of comorbidity risk.

Adolescent↗

PubMed2005

Management and outcomes of postoperative endophthalmitis since the endophthalmitis vitrectomy study: the Endophthalmitis Population Study of Western Australia (EPSWA)'s fifth report.

PURPOSE: To examine if changes in the diagnosis and management of postoperative endophthalmitis have occurred since 1995, and to identify factors that might predict final visual outcome. DESIGN: Retrospective, population-based, noncomparative, consecutive case series. PARTICIPANTS: Patients with clinically diagnosed endophthalmitis after cataract surgery and lens-related surgery in Western Australia from 1980 to 2000. METHODS: Endophthalmitis cases were identified using record linkage and cross-referencing with the surgical logbooks of vitreoretinal surgeons before validation by medical record review. MAIN OUTCOME MEASURES: Microbiological data (microorganisms isolated and antibiotic susceptibilities), diagnostic interventions, surgical procedures, therapeutic interventions, and visual acuity (VA). RESULTS: During the 21-year period, 213 episodes of endophthalmitis occurred after cataract surgery. Since 1995, both anterior chamber sampling and vitreous sampling have increased significantly. The overall use of vitrectomy has also increased, but we did not observe a difference according to presenting VA. Intravitreal antibiotic use increased significantly, whereas the use of both subconjunctival and IV antibiotics decreased. In one third of patients, the VA at least 6 months after admission for endophthalmitis was worse than 6/18. This was associated with treatment that did not include the use of oral antibiotics (odds ratio [OR], 3.86; 95% confidence interval [CI], 1.21-12.39; P = 0.02), growth from intraocular samples of organisms other than coagulase-negative staphylococci (OR, 9.84; 95% CI, 2.84-34.09; P<0.001), and a discharge VA worse than 6/18 (OR, 6.10; 95% CI, 1.63-22.89; P = 0.01). CONCLUSIONS: Although we observed noticeable changes in the diagnosis and management of endophthalmitis since 1995, visual outcomes have not improved and remain poor. Our finding that treatment with oral antibiotics may be associated with a better visual outcome warrants further investigation.

Aged↗

PubMed2005

Subsequent surgery after initial breast conserving surgery: a population based study.

BACKGROUND: In line with current Australian early breast cancer management guidelines, more women are having breast conserving surgery to treat breast cancer when appropriate. Some women will undergo further surgery because of involved margins, early local relapse, or other factors including patient choice. The aim of this study was to investigate whether socio-economic, demographic or hospital factors were associated with the risk of re-excision or subsequent mastectomy. METHODS: A record linkage population-based study on 12 711 women diagnosed with breast cancer in Western Australia from 1982 to 2000 who underwent breast surgery within 12 months of diagnosis was performed. Logistic regression was used to identify social, demographic and hospital factors associated with the risk of undergoing further surgery following initial breast conserving surgery. RESULTS: The proportion of women undergoing initial breast conserving surgery doubled from 33% in 1982-1985 to 72% in 1998-2000. The proportion of women who underwent further surgery following initial breast conserving surgery decreased from 50 to 30% over the same period. The risk of re-excision or subsequent mastectomy was between 2.4 (95% CI 1.7-3.4) and 5.0 (95% CI 3.4-7.4) times greater if initial surgery was performed in a non-metropolitan hospital compared to Perth hospitals. Younger women were between 1.7 (95% CI 1.4-2.0) and 2.1 (95% CI 1.5-3.0) times more likely to undergo re-excisions compared to women aged 50-64 years of age. CONCLUSIONS: Young women and women initially treated in non-metropolitan hospitals were at an increased risk of re-excision or a subsequent mastectomy following initial breast conserving surgery to treat breast cancer. Efforts need to be directed towards improving specialist health services outside of Perth if women continue to be treated for breast cancer in non-metropolitan hospitals.

Adult↗

PubMed2005

Inequalities in rural health care: differences in surgical intervention between metropolitan and rural Western Australia.

BACKGROUND: To compare surgical procedure rates between metropolitan and rural/remote residents in Western Australia (WA). METHODS: The WA Data Linkage System was used to identify all patients who underwent a procedure for cataract, ureteric calculi or urinary outflow obstruction symptoms for the time periods 1981-2000, 1981-1997 and 1981-1995, respectively. Age-standardized procedure rates were calculated and Poisson regression modelling was used to estimate effects of locality of residence and demographic covariates. RESULTS: Overall, rural/remote patients underwent first-time procedures for cataract (IRR 0.92; 95% CI 0.90-0.94), ureteric calculi (0.76; 0.72-0.80), or urinary outflow obstruction (0.71; 0.69-0.74) less frequently than patients in the metropolitan area. They were also significantly less likely to undergo multiple procedures for cataracts (0.90; 0.88-0.91) and ureteric calculi (0.69; 0.67-0.73). CONCLUSION: A distinctly reduced level of surgical intervention was found in rural patients for three generally non-life threatening conditions. The reasons for this require further investigation.

Adult↗

PubMed2005

Long-term survival outcomes following breast cancer surgery in Western Australia.

BACKGROUND: Mortality rates from breast cancer are stabilizing or falling in many developed countries including Australia, however, survival outcomes are known to vary by social, demographic and treatment related factors. The aim of the present study was to investigate how hospital, social and demographic factors were associated with survival outcomes from surgically treated breast cancer for all women living in Western Australia. METHODS: The WA Data Linkage System was used to access hospital morbidity, death and cancer information for all women diagnosed with invasive breast cancer in Western Australia 1982-2000. Relative survival and Cox proportional hazards regression analyses were used to identify social, demographic and hospital factors associated with an increased risk of dying from breast cancer or dying from any cause. RESULTS: Survival outcomes improved in all women diagnosed in more recent calendar periods. However, a significantly increased risk of dying was observed for women who underwent initial surgical treatment in regional public hospitals outside of the state capital, Perth. Consistent with other reports, women aged greater than 80 years and younger than 35 years at diagnosis also had poorer survival outcomes. Residential location, socioeconomic status and race were not associated with survival after adjusting for treatment, health and hospital related factors. CONCLUSIONS: Despite overall improvements in survival of women diagnosed with breast cancer in Western Australia, initial surgical treatment in public hospitals outside of Perth was associated with significantly poorer outcomes.

Adult↗

PubMed2005

Infected endoluminal stent-graft: implications for endotension, late endoleaks, and prophylactic antibiotics.

PURPOSE: To retrospectively review a case of stent-graft infection that presented as continued aneurysm expansion after endoluminal repair. CASE REPORT: A 75-year-old man with an asymptomatic 6.1-cm abdominal aortic aneurysm (AAA) was treated with a Talent stent-graft, which was complicated by postimplantation syndrome. At 1 year, a secondary intervention was performed for migration with type I endoleak. Despite the absence of a demonstrable endoleak thereafter, the AAA continued to expand until it was 9 cm in diameter and symptomatic. At this stage, 6 months after the secondary procedure, the graft was explanted and an axillobifemoral graft inserted. Propionibacterium acnes was cultured from all specimens of thrombus, aortic wall, and graft. The patient recovered and was asymptomatic until his death from myocardial infarction 6 months after discharge. CONCLUSIONS: Stent-graft infection may be a cause of unexplained endotension. Special culture techniques may be required to identify the infecting organism. Prophylactic antibiotics against skin organisms should be considered for all implantations and arterial diagnostic and therapeutic procedures traversing a stent-graft.

Aged↗

PubMed2004

Review of survival curves for colorectal cancer.

PURPOSE: Actuarial and Product Limited (i.e., Kaplan-Meier) estimates of survival are commonly used in the literature to describe outcomes in patients treated for cancer. Terms such as cancer-specific and cancer-free survival are frequently quoted, although often without clear definitions. This study was designed to compare survival estimates using the Kaplan-Meier method on the same population of patients but using different definitions of what constitutes an event. This was to highlight some of the variation that can occur when different techniques are used to perform these calculations. METHODS: Data were obtained from a prospective database that had recorded all patients presenting with colorectal cancer from 1996 to 2002. Using this information, we calculated the 1) overall (all-cause mortality), 2) cancer-specific, 3) cancer-free, 4) recurrence-free, and 5) relative survival (and 95 percent confidence intervals) at five years postpresentation. RESULTS: The study included 497 patients with a mean age of 68 years, and a male-to-female ratio of 1.3:1. They were followed for a mean of 2.2 years (standard deviation, +/-1.1), with 50 patients (10.1 percent) followed for more than five years. The various survivals at five years were: 1) overall survival, 55.6 percent (95 percent confidence interval, 49.1-62.1 percent), 2) cancer-specific survival, 67 percent (95 percent confidence interval, 60.9-73.1 percent), 3) cancer-free survival, 49.9 percent (95 percent confidence interval, 43.6-56.2 percent), 4) recurrence-free survival, 43.5 percent (95 percent confidence interval, 37.2-49.8 percent), and 5) relative survival, 73.4 percent (95 percent confidence interval, 65.4-81.4 percent). CONCLUSIONS: The five-year survival calculations for this group of patients with colorectal cancer varied by as much as 30 percent depending on how the data was censored. This highlights that there needs to be a clear and accountable definition on how survival curves are calculated and presented in the literature to allow for meaningful interpretation and comparisons.

Aftercare↗