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Background: Vascular Biochemistry and Haematology Outcome Models (VBHOM) adopted the approach of using a minimum data set to model outcome. This study aimed to test such a model on a cohort of patients undergoing open elective and non-elective abdominal aortic aneurysm (AAA) repair. Methods: A binary logistic regression model of risk of in-hospital mortality was built from the 2002-2004 submission to the UK National Vascular Database (NVD) (2718 patients). The subset of NVD data items used comprised serum levels of urea, sodium and potassium, haemoglobin, white cell count, sex, age and mode of admission. The model was applied prospectively using Hosmer-Lemeshow methodology to a test data set from the Cambridge Vascular Unit. Results: The validation set contained 327 patients, of whom 208 had elective AAA repair and 119 had emergency repair of a ruptured AAA. Outcome following elective and non-elective AAA repair could be described accurately using the same model. The overall mean predicted risk of death was 14.13 per cent, and 48 deaths were predicted. The actual number of deaths was 53 (X² = 8.40, 10 d.f., P = 0.590; no evidence of lack of fit). The model also demonstrated good discrimination (c-index = 0.852). Conclusion: The VBHOM approach has the advantage of using simple, objective clinical data that are easy to collect routinely. The VBHOM data items potentially allow prediction of risk in an individual patient before aneurysm surgery. [ABSTRACT FROM AUTHOR]

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 < 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. [ABSTRACT FROM AUTHOR]

Background: The aim was to assess the relationship between hospital volume and outcome after abdominal aortic aneurysm (AAA) surgery in the UK. Methods: Hospital Episode Statistics (2000-2005) were classified as elective, urgent or ruptured AAA repair. Analysis was by modelling of mortality rate, complication rate and length of hospital stay with regard to the annual operative volume, after risk adjustment. Results: There were 112 545 diagnoses, or repairs, of AAAs, of which 26 822 were infrarenal aneurysms. The mean mortality rate was 7.4, 23.6 and 41-8 per cent for elective, urgent and ruptured AAA repair respectively. Elective AAA repair undertaken at high-volume hospitals showed volume-related improvements in mortality (P < 0.001). Patients were discharged from hospital earlier (P < 0.001). The critical volume threshold was 32 elective AAA repairs per year. For urgent repair, patients at high-volume hospitals had a reduced mortality rate (P = 0.017) with an increased length of stay (P = 0.041). There was no relationship between volume and outcome for ruptured AAA repairs. Conclusion: Increased annual volumes were associated with significant reductions in mortality for elective and urgent AAA repair, but not for repair of ruptured AAAs. [ABSTRACT FROM AUTHOR]

Background: This study investigated the volume-outcome relationship for abdominal aortic aneurysm (AAA) surgery and quantified critical volume thresholds. Methods: PubMed, EMBASE and the Cochrane library were searched for articles on the operation volume-outcome relationship in elective and ruptured AAA surgery. UK Hospital Episode Statistics data were also considered. Elective and ruptured AAA repairs were dealt with separately. The data were meta-analysed, and the odds ratios (95 per cent confidence interval) for mortality at higher- and lower-volume hospitals were compared. Volume thresholds were identified from each paper. Results: The analysis included 421 299 elective and 45 796 ruptured AAA operations. Significant relationships between mortality and annual volume were noted for both groups. Overall, the weighted odds ratio was 0.66 (0.65 to 0.67) for elective repair at a threshold of 43 AAAs per annum and (0.73 to 0.82) for ruptured aneurysm repair at a threshold of 15 AAAs per annum, both in favour of high-volume institutions. Conclusion: Higher annual operation volumes are associated with significantly lower mortality in both elective and ruptured AAA repair. This suggests that AAA surgery should be performed only at higher-volume centres. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]