Margaret Boult

A Model to Predict Outcomes for Endovascular Aneurysm Repair Using Preoperative Variables

PURPOSE Models have been developed to predict the likely outcomes of endovascular aneurysm repair (EVAR) for patients, based on a longitudinal Australian audit. METHODOLOGY Mid-term progress of 961 Australian patients who underwent EVAR has been collected and used to develop predictive models for 17 outcomes. Stepwise forward logistic regressions determined the significant preoperative patient variables to be included in each outcome model. An interactive program was subsequently developed to allow surgeons to review the predicted success rates for patients about to undergo the procedure. Each model was assessed using a global goodness of fit test and was internally validated using bootstrapping. RESULTS Eight pre-operative variables were included in the interactive model for 17 outcomes. The eight variables used were aneurysm size, age, ASA, gender, creatinine, aortic neck angle, infrarenal neck diameter and infrarenal neck length. The outcomes predicted included perioperative mortality, perioperative morbidity, mid-term survival and reintervention rates. All outcome models achieved reasonable goodness of fit, with the exception of the model for conversion to open repair (p=0.04). With respect to validation, survival, aneurysm related deaths, migrations, ruptures and conversions to open repair performed best in terms of predictive discrimination. Models for survival, migrations and conversions to open repairs performed best in terms of bias corrected R-squared index. The models with the smallest calibration error were 3 and 5 year survival, early deaths and mid-term type I endoleaks. CONCLUSIONS An interactive model is available, which can assist vascular surgeons to evaluate the expected outcomes for a particular patient undergoing EVAR. The validated model is useful for counselling and pre-operative decision making.

Patterns of Surgical Treatment for Women with Breast Cancer in Relation to Age

Abstract:  Although treatment recommendations have been advocated for all women with early breast cancer regardless of age, it is generally accepted that different treatments are preferred based on the age of the patient. The aim of this study was to assess the pattern of breast cancer surgery after adjusting for other major prognostic factors in relation to patient age. Data on cancer characteristics and surgical procedures in 31,298 patients with early breast cancer reported to the National Breast Cancer Audit between 1999 and 2006 were used for the study. There was a close association between age and surgical treatment pattern after adjusting for other prognostic factors, including tumor size, histologic grade, number of tumors, lymph node positivity, lymphovascular invasion (LVI), and extensive intraduct component. Breast Conserving Surgery (BCS) was highest among women aged ≤40 years (OR = 1.140; 95% CI: 1.004–1.293) compared to women aged 51–70 years (reference group). BCS was lowest in women aged >70 years (OR = 0.498, 95% CI: 0.455–0.545). Significantly more women aged ≤50 years underwent more than one operation for breast conservation (20.4–24.8%) compared with women aged >50 years (11.4–17.0%). Women aged >70 years were more likely to receive no surgical treatment, 3.5% versus 1.0–1.3% in all other age groups (≤40, 41–50 51–70 years). There is an association between patient age and the type of breast cancer surgery for women in Australia and New Zealand. Women age ≤40 years are more likely to undergo BCS despite having adverse histologic features and have more than one procedure to achieve breast conservation. Older women (>70 years) more commonly undergo mastectomy and are more likely to receive no surgical treatment.

The Outcome of Endovascular Repair of Small Abdominal Aortic Aneurysms

Objective:To assess the outcome of endovascular repair (EVAR) of small abdominal aortic aneurysms (AAA, ≤5.5 mm maximum diameter) in Australia. Summary Background Data:Randomized trials have suggested that small AAAs should not be treated by open surgery. EVAR is associated with less perioperative mortality than open surgery for large AAAs. We assessed the outcome of EVAR of small AAAs as part of a national audit. Methods:ASERNIP-S carried out a prospective audit of EVAR performed between November 1999 and May 2001 in Australia. A total of 478 of the 961 patients entered underwent treatment of a small AAA. Data were collected regarding preoperative characteristics, procedural outcome, and intermediate success. Median follow-up was 3.2 years. Data were analyzed using Kaplan-Meier and Cox proportional hazard analyses. Results:The 30-day mortality and technical success rates were 1.1% and 98%, respectively. Postoperative complications occurred in 29%. Survival was 84% and 52% at 3 and 5 years, respectively. Primary, assisted primary, and secondary clinical success rates were 72%, 79%, and 82%, respectively, at 3 years. Reintervention rate was 11% at 3 years; however, 15% of patients continued to have significant aortic sac enlargement. Survival was reduced in patients considered unfit for general anesthesia (odds ratio = 2.6; 95% confidence interval, 1.4–4.8, P = 0.002) or those who had elevated preoperative serum creatinine (odds ratio = 2.0; 95% confidence interval, 1.3–3.0, P = 0.001). Conclusions:EVAR can be carried with good perioperative outcome in patients with small AAA; however, intermediate success is hampered by the need for reintervention and continued aortic sac enlargement. At present, widespread treatment of small AAAs by EVAR would appear inappropriate.

Fluorescence induction transients indicate altered absorption cross-section during light-state transitions in the cyanobacterium Synechococcus 6301

Abstract State 1–State 2 transitions in the cyanobacterium Synechococcus 6301 were observed using a lock-in amplifier to detect the fluorescence generated by a modulated excitation beam. Millisecond fluorescence induction transients were recorded for cells in State 1 and State 2. Comparison of the transients suggests that excitation energy distribution in this cyanobacterium is regulated by changes in the absorption cross-section of Photosystem II.

Personalised Predictions of Endovascular Aneurysm Repair Success Rates: Validating the ERA Model with UK Vascular Institute Data

OBJECTIVE The objective of this study was to externally validate the existing Australian Endovascular aneurysm repair Risk Assessment (ERA) Model using data from a major vascular centre in the United Kingdom. METHODS Data collected from 312 endovascular abdominal aortic aneurysm repair patients at St Georges Vascular Institute, London, UK were fitted to the ERA Model. RESULTS Despite St Georges patients being sicker (p < 0.001), having larger aneurysms (p < 0.001) and being more likely to die (p < 0.05) than the Australian patients, their data fitted the ERA Model well for the risk factors early death, aneurysm-related death, three-year survival and type I endoleaks as evidenced by higher area under ROC curves and/or higher R(2) goodness of fit statistics than the Australian data. CONCLUSIONS The first external validation of the ERA Model using data from St Georges Vascular Institute suggests that this tool can be used in different countries and hospital settings. The authors believe the ERA Model is robust and allows valid personalised predictions of outcomes by surgeons treating routine aneurysms as well as those in tertiary referral practices with more adverse outcomes.

CLINICAL AUDITS: WHY AND FOR WHOM

Every surgical activity poses some element of risk to the public and should include a quality control initiative. Surgical audit is one strategy used to maintain and/or improve standards in surgical care. The Royal Australasian College of Surgeons is committed to ensuring best practice in surgical care and strongly endorses the use of audits to achieve this. This review provides an overview of clinical audit and its role in surgical practice.

National breast cancer audit: overview of invasive breast cancer management.

Background:  The National Breast Cancer Audit is an initiative of the Breast Section of the Royal Australasian College of Surgeons collecting surgical information in early breast cancer. It is managed in conjunction with the Australian Safety and Efficacy Register of New Interventional Procedures – Surgical. An overview of results for invasive breast cancer from January 1999 until December 2004 is presented to provide preliminary data for participating surgeons.

Development of an automated measure of iliac artery tortuosity that successfully predicts early graft-related complications associated with endovascular aneurysm repair

OBJECTIVES Iliac artery tortuosity has been linked to the likelihood of complications following endovascular aneurysm repair (EVAR). Measures of tortuosity can be established from CT images; however, the reproducibility of existing scoring techniques has not been clearly established. It remains unclear whether it is tortuosity at focal locations or for the vessel as a whole that is most relevant to adverse events. The two aims of this study were to develop an automated measure of iliac artery tortuosity to assist with surgical planning by providing an objective assessment of procedural difficulty, and to correlate this measure with early postoperative outcomes. DESIGN AND METHODS Unlike existing approaches, the present measure of tortuosity considers spatial scale, which incorporates the effects of local anatomy. A computerized imaging algorithm was used to segment vasculature and establish a medial line and vascular boundary from contrast enhanced CT scans of 150 patients undergoing EVAR. Two tortuosity measures were examined: curvature and vessel to straight-line length (L1/L2-ratio). For a given spatial scale, the maximum tortuosity was computed on both iliac arteries and the artery with the lower maximum was selected for analysis. Correlation of tortuosity with early (<30 day) and longer-term graft-related complications was assessed. RESULTS Maximal tortuosity at a 10 mm scale was a significant predictor of early (<30 day) complications (p = .016 for curvature and p = .006 for L1/L2-ratio), but not of long-term complications. Aneurysmal diameter was independent of tortuosity (Pearsons r value = -.006). CONCLUSION The results demonstrate that, at a local scale, tortuosity measures are correlated with early outcomes. The spatial scale at which tortuosity is measured is important. The optimal scale of 10 mm implies that adverse events could be linked to a focal anatomical location.

ASERNIP-S: International trend setting

The Australian Safety and Efficacy Register of New Interventional Procedures – Surgical (ASERNIP‐S) came into being 10 years ago to provide health technology assessments specifically tailored towards new surgical techniques and technologies. It was and remains the only organisation in the world to focus on this area of research. Most funding has been provided by the Australian Government Department of Health, and assessments have helped inform the introduction of new surgical techniques into Australia. ASERNIP‐S is a project of the Royal Australasian College of Surgeons. The ASERNIP‐S program employs a diverse range of methods including systematic reviews, technology overviews, assessments of new and emerging surgical technologies identified by horizon scanning, and audit. Support and guidance for the program is provided by Fellows of the Royal Australasian College of Surgeons. ASERNIP‐S works closely with consumers to produce health technology assessments and audits, as well as consumer information to keep patients fully informed of research. Since its inception, the ASERNIP‐S program has developed a strong international profile through the production of over 60 reports on evidence‐based surgery, surgical technologies and audit. The work undertaken by ASERNIP‐S has evolved from assessments of the safety and efficacy of procedures to include guidance on policies and surgical training programs. ASERNIP‐S needs to secure funding so that it can continue to play an integral role in the improvement of quality of care both in Australia and internationally.

NATIONAL BREAST CANCER AUDIT: DUCTAL CARCINOMA IN SITU MANAGEMENT IN AUSTRALIA AND NEW ZEALAND

Background:  Ductal carcinoma in situ (DCIS) is a significant issue in Australia and New Zealand with rising incidence because of the implementation of mammographic screening. Current information on its natural history is unable to accurately predict progression to invasive cancer. In 2003, the National Breast Cancer Centre in Australia published recommendations for DCIS. In Australia and New Zealand, the National Breast Cancer Audit collects information on DCIS cases. This article will examine these recommendations and provide information from the audit on current DCIS management.