Charles N McCollum

Preoperative cardiopulmonary exercise testing and risk of early mortality following abdominal aortic aneurysm repair.

Cardiopulmonary exercise testing (CPET) provides an objective assessment of functional capacity. The aim of this study was to assess whether preoperative CPET identifies patients at risk of early death following elective open and endovascular abdominal aortic aneurysm (AAA) repair.

Logistic risk model for mortality following elective abdominal aortic aneurysm repair

The aim was to develop a multivariable risk prediction model for 30‐day mortality following elective abdominal aortic aneurysm (AAA) repair.

Evaluation of five risk prediction models for elective abdominal aortic aneurysm repair using the UK National Vascular Database

There is no consensus on the best risk prediction model for mortality following elective abdominal aortic aneurysm (AAA) repair. The objective was to evaluate the performance of five risk prediction models using the UK National Vascular Database (NVD).

National risk prediction model for elective abdominal aortic aneurysm repair.

Mortality results for elective abdominal aortic aneurysm (AAA) repair are published by the Vascular Society of Great Britain and Ireland. These mortality results are not currently risk‐adjusted. The objective of this study was to develop a national risk prediction model for elective AAA repair.

What are the Risk Factors for Renal Failure following Open Elective Abdominal Aortic Aneurysm Repair

OBJECTIVESnRenal failure following abdominal aortic aneurysm (AAA) repair is a common and significant complication. The objective of this study was to identify risk factors for renal failure following open elective AAA repair.nnnDESIGNnA retrospective analysis of prospectively collected multi-centre data.nnnMATERIALSnConsecutive data on patients undergoing open elective AAA repair were collected between January 2000 and December 2010. Patients with pre-operative serum creatinine >200xa0μmol/L were excluded.nnnMETHODSnRenal failure was reported by clinicians and included all patients requiring post-operative renal-replacement therapy. Univariate and multivariate analyses were used to identify renal failure risk factors. A simplified clinical risk score was developed.nnnRESULTSnPost-operative renal failure occurred in 140 (6.0%) of 2347 patients and was associated with age >75 (ORxa0=xa01.58, 95%CI 1.11-2.26), symptomatic AAA (ORxa0=xa01.77, 95%CI 1.24-2.52), supra/juxta renal AAA (ORxa0=xa02.17, 95%CI 1.32-3.57) pre-operative serum creatinine >150 (ORxa0=xa02.75, 95%CI 1.69-4.50), treated hypertension (ORxa0=xa01.87, 95%CI 1.28-2.74), and respiratory disease (ORxa0=xa02.08, 95%CI 1.45-2.97). Patients with post-operative renal failure had significantly higher 30-day mortality (35.0% vs. 4.3%, pxa0<xa00.001).nnnCONCLUSIONSnRenal failure following open elective AAA repair was associated with an increased risk of mortality. Risk factors for post-operative renal failure were identified and a simple clinical risk score developed to facilitate focussed care strategies for high-risk patients.

Comparison of Three Contemporary Risk Scores for Mortality Following Elective Abdominal Aortic Aneurysm Repair

Objective/background A number of contemporary risk prediction models for mortality following elective abdominal aortic aneurysm (AAA) repair have been developed. Before a model is used either in clinical practice or to risk-adjust surgical outcome data it is important that its performance is assessed in external validation studies. Methods The British Aneurysm Repair (BAR) score, Medicare, and Vascular Governance North West (VGNW) models were validated using an independent prospectively collected sample of multicentre clinical audit data. Consecutive, data on 1,124 patients undergoing elective AAA repair at 17 hospitals in the north-west of England and Wales between April 2011 and March 2013 were analysed. The outcome measure was in-hospital mortality. Model calibration (observed to expected ratio with chi-square test, calibration plots, calibration intercept and slope) and discrimination (area under receiver operating characteristic curve [AUC]) were assessed in the overall cohort and procedural subgroups. Results The mean age of the population was 74.4 years (SD 7.7); 193 (17.2%) patients were women and the majority of patients (759, 67.5%) underwent endovascular aneurysm repair. All three models demonstrated good calibration in the overall cohort and procedural subgroups. Overall discrimination was excellent for the BAR score (AUC 0.83, 95% confidence interval [CI] 0.76–0.89), and acceptable for the Medicare and VGNW models, with AUCs of 0.78 (95% CI 0.70–0.86) and 0.75 (95% CI 0.65–0.84) respectively. Only the BAR score demonstrated good discrimination in procedural subgroups. Conclusion All three models demonstrated good calibration and discrimination for the prediction of in-hospital mortality following elective AAA repair and are potentially useful. The BAR score has a number of advantages, which include being developed on the most contemporaneous data, excellent overall discrimination, and good performance in procedural subgroups. Regular model validations and recalibration will be essential.

Delayed Carotid Surgery: What Are the Causes in the North West of England?

INTRODUCTIONnCarotid endarterectomy (CEA) should be performed within two weeks of symptoms for patients with carotid stenosis >50%. Whether these standards are being achieved and causes of delay between symptoms and CEA were investigated.nnnDESIGNnAn analysis of prospectively collected multi-centre data.nnnMATERIALSnConsecutive data for patients undergoing CEA between January-2006 and September-2010 were collected. Asymptomatic patients and those with no details on the timing of cerebral symptoms were excluded.nnnMETHODSnDelay from symptom to CEA was defined as more than two weeks and prolonged-delay more than eight weeks. Univariable and multivariable analyses were used to identify factors associated with these delays.nnnRESULTSnOf 2147 patients with symptoms of cerebral ischaemia, 1522(70.9%) experienced delay and 920(42.9%) experienced prolonged delay. Patients with ischaemic heart disease were more likely to experience delay (ORxa0=xa01.56; 95% CI 1.11-2.19, pxa0=xa00.011), whereas patients with stroke (ORxa0=xa00.77; 95%CI 0.63-0.94, pxa0=xa00.011) and those treated at hospitals with a stroke-prevention clinic (ORxa0=xa00.57; 95%CI 0.46-0.71, pxa0<xa00.001) were less likely to experience delay. Patients treated after the publication of National Institute for Health and Clinical Excellence (NICE) guidelines were less likely to experience prolonged delay (ORxa0=xa00.77; 95%CI 0.65-0.91, pxa0=xa00.003) but not delay.nnnCONCLUSIONnFew patients achieved CEA within two weeks of symptoms. Introducing stroke-prevention clinics with one-stop carotid imaging appears important.

Authors' reply: Logistic risk model for mortality following elective abdominal aortic aneurysm repair (Br J Surg 2011; 98: 652–658)

Sir I wish to congratulate Professor U. Güller and colleagues for their impressive work on the negative appendicectomy and perforation rates following laparoscopic appendicectomy. I wish to draw the authors’ attention to some comments. This study was based on a prospective database including 7964 patients who underwent laparoscopic appendicectomy, rather than on the actual number of patients having surgery for a preoperative diagnosis of appendicitis. This probably explains their very low incidence (6·4 per cent) of negative appendicectomy. For instance, any female patient with a gynaecological pathology such as ruptured ovarian cyst would have followed a different treatment pathway and therefore not been included in this analysis. Another bias towards having a low negative appendicectomy rate is that the diagnosis of appendicitis was based on a subjective perception of macroscopically abnormal appendix, rather than more objective microscopic findings1. It seems that an inversely proportional correlation between negative appendicectomy and perforation rates exists, such as among the female patients in this article. Although some suggest that perforated and non-perforated appendicitis may simply be fundamentally different diseases2, we should not aim for reducing the negative appendicectomy rate as a favourable clinical endpoint and instead keep a low threshold for laparoscopic exploration in case of equivocal diagnosis3. Finally, although clinical examination remains paramount to the diagnosis of appendicitis, I agree with the authors that the widespread availability of radiological imaging could have a favourable impact on the accuracy of the preoperative diagnosis, especially in elderly patients4. C. Berney Bankstown-Lidcombe Hospital, Bankstown, New South Wales, Australia (e-mail: berneycr@hotmail.com) DOI: 10.1002/bjs.7663