Editor's Choice--External Validation of Models Predicting Survival After Ruptured Abdominal Aortic Aneurysm Repair.

OBJECTIVE: Prediction of survival after intervention for ruptured abdominal aortic aneurysms (RAAA) may support case mix comparison and tailor the prognosis for patients and relatives. The objective of this study was to assess the performance of four prediction models: the updated Glasgow Aneurysm Score (GAS), the Vancouver scoring system, the Edinburgh Ruptured Aneurysm Score (ERAS), and the Hardman index. DESIGN, MATERIALS, AND METHODS: This was a retrospective cohort study in 449 patients in ten hospitals with a RAAA (intervention between 2004 and 2011). The primary endpoint was combined 30 day or in hospital death.The accuracy of the prediction models was assessed for discrimination (area under the curve [AUC]). An AUC>0.70 was considered sufficiently accurate. In studies with sufficiently accurate discrimination, correspondence between the predicted and observed outcomes (i.e. calibration) was recalculated. RESULTS: The AUC of the updated GAS was 0.71 (95% confidence interval [CI] 0.66-0.76), of the Vancouver score was 0.72 (95% CI 0.67-0.77), and of the ERAS was 0.58 (95% CI 0.52-0.65). After recalibration, predictions by the updated GAS slightly overestimated the death rate, with a predicted death rate 60% versus observed death rate 54% (95% CI 44-64%). After recalibration, predictions by the Vancouver score considerably overestimated the death rate, with a predicted death rate 82% versus observed death rate 62% (95% CI 52-71%). Performance of the Hardman index could not be assessed on discrimination and calibration, because in 57% of patients electrocardiograms were missing. CONCLUSIONS: Concerning discrimination and calibration, the updated GAS most accurately predicted death after intervention for a RAAA. However, the updated GAS did not identify patients with a ≥95% predicted death rate, and therefore cannot reliably support the decision to withhold intervention.

Effect of regional cooperation on outcomes from ruptured abdominal aortic aneurysm.

BACKGROUND: Care for patients with a ruptured abdominal aortic aneurysm (rAAA) in the Amsterdam ambulance region (The Netherlands) was concentrated into vascular centres with a 24-h full emergency vascular service in cooperation with seven referring regional hospitals. Previous population-based survival after rAAA in the Netherlands was 46 (95 per cent confidence interval (c.i.) 43 to 49) per cent. It was hypothesized that regional cooperation would improve survival. METHODS: This was a prospective observational cohort study carried out simultaneously with the Amsterdam Acute Aneurysm Trial. Consecutive patients with an rAAA between 2004 and 2011 in all ten hospitals in the Amsterdam region were included. The primary outcome was 30-day survival after admission. Multivariable logistic regression, including age, sex, co-morbidity, intervention (endovascular or open repair), preoperative systolic blood pressure, cardiopulmonary resuscitation and year of intervention, was used to assess the influence of hospital setting on survival. RESULTS: Of 453 patients with rAAA from the Amsterdam ambulance region, 61 did not undergo intervention; 352 patients were treated surgically at a vascular centre and 40 at a referring hospital. The regional survival rate was 58.5 (95 per cent c.i. 53.9 to 62.9) per cent (265 of 453). After multivariable adjustment, patients treated at a vascular centre had a higher survival rate than patients treated surgically at a referring hospital (adjusted odds ratio 3.18, 95 per cent c.i. 1.43 to 7.04). CONCLUSION: After regional cooperation, overall survival of patients with an rAAA improved. Most patients were treated in a vascular centre and in these patients survival rates were optimal.

Outcomes after open repair for ruptured abdominal aortic aneurysms in patients with friendly versus hostile aortoiliac anatomy.

OBJECTIVES: In patients with a ruptured abdominal aortic aneurysm (RAAA), anatomic suitability for endovascular aneurysm repair (EVAR) depends on aortic neck and iliac artery characteristics. If the aortoiliac anatomy is unsuitable for EVAR ("hostile anatomy"), open repair (OR) is the next option. We hypothesized that the death rate for OR is higher in patients with hostile anatomy than in patients with friendly anatomy. METHODS: We conducted an observational cohort study in 279 consecutive patients with an RAAA treated with OR between 2004 and 2011. The primary endpoint was 30-day or in-hospital death. Aortoiliac anatomy (friendly vs. hostile) was determined prospectively by the vascular surgeon and the interventional radiologist treating the patient. A multivariable logistic regression analysis was done to assess the risk of dying in patients with hostile anatomy after adjustment for age, sex, comorbidity, and hemodynamic stability. RESULTS: Aortoiliac anatomy was friendly in 71 patients and hostile in 208 patients. Death rate was 38% (95% confidence interval (CI): 28 to 50%) in patients with friendly anatomy and 30% (95% CI: 24 to 37%) in patients with hostile anatomy (p = .23). After multivariable adjustment, the risk of dying was not higher in patients with hostile anatomy (adjusted odds ratio 0.744, 95% CI 0.394 to 1.404). CONCLUSION: The death rate after open repair for an RAAA is comparable in patients with friendly and hostile aortoiliac anatomy.

Cost-effectiveness and cost-utility of endovascular versus open repair of ruptured abdominal aortic aneurysm in the Amsterdam Acute Aneurysm Trial.

BACKGROUND: Minimally invasive endovascular aneurysm repair (EVAR) could be a surgical technique that improves outcome of patients with ruptured abdominal aortic aneurysm (rAAA). The aim of this study was to analyse the cost-effectiveness and cost-utility of EVAR compared with standard open repair (OR) in the treatment of rAAA, with costs per 30-day and 6-month survivor as outcome parameters. METHODS: Resource use was determined from the Amsterdam Acute Aneurysm (AJAX) trial, a multicentre randomized trial comparing EVAR with OR in patients with rAAA. The analysis was performed from a provider perspective. All costs were calculated as if all patients had been treated in the same hospital (Onze Lieve Vrouwe Gasthuis, teaching hospital). RESULTS: A total of 116 patients were randomized. The 30-day mortality rate was 21 per cent after EVAR and 25 per cent for OR: absolute risk reduction (ARR) 4·4 (95 per cent confidence interval (c.i.) -11·0 to 19·7) per cent. At 6 months, the total mortality rate for EVAR was 28 per cent, compared with 31 per cent among those assigned to OR: ARR 2·4 (-14·2 to 19·0) per cent. The mean cost difference between EVAR and OR was €5306 (95 per cent c.i. -1854 to 12,659) at 30 days and €10,189 (-2477 to 24,506) at 6 months. The incremental cost-effectiveness ratio per prevented death was €120,591 at 30 days and €424,542 at 6 months. There was no significant difference in quality of life between EVAR and OR. Nor was EVAR superior regarding cost-utility. CONCLUSION: EVAR may be more effective for rAAA, but its increased costs mean that it is unaffordable based on current standards of societal willingness-to-pay for health gains.

Systematic review and meta-analysis of population-based mortality from ruptured abdominal aortic aneurysm.

BACKGROUND: A substantial proportion of patients with a ruptured abdominal aortic aneurysm (rAAA) die outside hospital. The objective of this study was to estimate the total mortality, including prehospital deaths, of patients with rAAA. METHODS: This was a systematic review and meta-analysis following the MOOSE guidelines. The Embase, MEDLINE and Cochrane Library databases were searched. All population-based studies reporting both prehospital and in-hospital mortality in patients with rAAA were included. Studies were assessed for methodological quality and heterogeneity, and pooled estimates of mortality from rAAA were calculated using a random-effects model. RESULTS: From a total of 3667 studies, 24 retrospective cohort studies, published between 1977 and 2012, met the inclusion criteria. The quality of included studies varied, in particular the method of determining prehospital deaths from rAAA. The estimated pooled total mortality rate was 81 (95 per cent confidence interval 78 to 83) per cent. A decline in mortality was observed over time (P = 0·002); the pooled estimate of total mortality in high-quality studies before 1990 was 86 (83 to 89) per cent, compared with 74 (72 to 77) per cent since 1990. Some 32 (27 to 37) per cent of patients with rAAA died before reaching hospital. The in-hospital non-intervention rate was 40 (33 to 47) per cent, which also declined over the years. CONCLUSION: The pooled estimate of total mortality from rAAA is very high, although it has declined over the years. Most patients die outside hospital, and there is no surgical intervention in a considerable number of those who survive to reach hospital.

Controlled hypotension in patients suspected of a ruptured abdominal aortic aneurysm: feasibility during transport by ambulance services and possible harm.

OBJECTIVE: To evaluate a controlled hypotension protocol for patients suspected of a ruptured aneurysm of the abdominal aorta (RAAA) and to identify possible harm to patients with a final diagnosis other than RAAA. DESIGN: Retrospective analysis of patients suspected of RAAA and transported by Amsterdam ambulance services between January 2006 and October 2007. PATIENTS AND METHODS: Protocol was assessed by reviewing systolic blood pressure (<80 mmHg, 80-100 mmHg or >100 mmHg), administered fluid volume and verbal responsiveness during transport. Patients who could possibly have been harmed by controlled hypotension were identified by final diagnoses. RESULTS: Fluid administration was according to protocol in 220 of 266 patients analysed for protocol adherence. The remaining patients received too much (21 patients) or too little fluid (25 patients). Data were missing in 29 patients. A RAAA was diagnosed in 81 (27%) of all 295 patients analysed for final diagnosis. Controlled hypotension was achieved in 10% of all patients and in 17% of patients with RAAA. Three patients (1%) with diagnosis other than RAAA were possibly at risk by implementing controlled hypotension. CONCLUSIONS: Protocol was followed in 83% and protocol violations occurred in 17% of patients. The risk of implementing controlled hypotension for all patients suspected of an RAAA by the ambulance staff was low.