Impact of delay on survival in patients with ruptured abdominal aortic aneurysm

Rupture of the abdominal aortic aneurysm (RAAA) is a common surgical emergency. Surgical treatment of this condition carries a high morbidity and mortality rate. For successful outcome, an early diagnosis and prompt treatment are essential. However, recently, some centers have reported better results in patients whose surgery had been delayed because of interhospital transfer. Delay in treatment sometimes occurs as patients are transferred from one institution to another where specialized vascular care is available. This retrospective study sought to determine the effect of delay in treatment on the mortality of patients with RAAA repair.The time from arrival at the emergency room to surgery and operative time were obtained from the case notes of 45 consecutive patients with RAAA. Patients' physiology scores on admission were calculated using V-POSSUM for the RAAA model.Thirty-five patients were diagnosed with RAAA in the emergency room and were transferred to surgery. These patients were divided into two groups: patients who had surgery within 1 hour (n = 23) and those in whom surgery was delayed for up to 4 hours (n = 12).There was no significant difference in physiology score between the two groups (p = .12). The time to surgery and operative time with death as the outcome were plotted on a logistic regression model that showed that the delay in surgical treatment increases the mortality rate following RAAA repair (p = .041). Furthermore, a long operative time was associated with a higher surgical mortality rate (p = .029).Delay to surgery and a long operation increase the mortality rate following RAAA repair. However, delay to surgery alone did not influence the mortality rate.     

The post-operative mortality of ruptured abdominal aortic aneurysm repair.

INTRODUCTION: Late peri-operative death after ruptured abdominal aortic aneurysm (RAAA) repair is usually due to multiple-organ failure. The aim of this study was to identify any factors that are associated with mortality in this group of patients. METHODS: A retrospective case-note review of a single decade's operative experience of RAAA repair in a single centre. Only those patients with confirmed rupture at laparotomy were included. Sixty-three pre- intra- and post-operative variables were recorded where possible for each patient who survived surgery and the initial 24-hours post-operatively. Multi-variate analysis was performed using stepwise logistic regression. The P-POSSUM, RAAA-POSSUM, RAAA-POSSUM (physiology only), V-POSSUM, and V-POSSUM (physiology only) models were all compared to determine how each performed in these patients. RESULTS: Two hundred and twenty-three cases of confirmed RAAA were identified, of whom 139 survived the operation and initial 24-hours post-operatively. In-hospital mortality in this group of patients was 32.4%. Variables significantly associated with mortality after multi-variate analysis, were low intra-operative systolic blood pressure, the presence of a consultant anaesthetist at the initial operation and the development of cardiac, renal or gastro-intestinal complications. All POSSUM models except the V-POSSUM and P-POSSUM (physiology only) models demonstrated no significant lack of fit in this dataset. DISCUSSION: Factors associated with delayed peri-operative death after RAAA are not the same as those previously found to be associated with overall peri-operative mortality after RAAA repair.     

Evaluation of surgical performance using V-POSSUM risk-adjusted mortality rates

Vascular-Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (V-POSSUM) is a risk-adjusted scoring system for predicting 30-day mortality in patients undergoing vascular surgery. It can assess surgical performance by comparing predicted deaths with observed deaths. The aim of this analysis was to assess trends in surgical performance over time using risk-adjusted 30-day mortality as the primary outcome. Major vascular surgery procedures (n = 454) were prospectively scored for V-POSSUM between 1995 and 2006. Procedures were divided into 11 consecutive time bands. Observed and predicted deaths were compared using the logistic regression equation derived for V-POSSUM. The observed death rates decreased over time, as did the predicted number of deaths calculated from the V-POSSUM scores. The overall predicted mortality rate was 17.2% and the rate varied with the 12-month period, with a high of 23.9% and a low of 9.2%. The downward trend in the predicted rate shows that the patient risk factors have changed over time and that the risk of dying has declined by almost 50% (from 21.6 to 11.1%). There was a trend towards improved surgical performance over time, with a drop in the observed to predicted ratios of deaths. Observed and predicted deaths changed over the study periods. There was a trend towards improved performance compared with the risk-adjusted predicted mortality. V-POSSUM is a useful tool in the longitudinal assessment of performance in major vascular surgery.     

Prognostic scoring in ruptured abdominal aortic aneurysm: a prospective evaluation

BACKGROUND: Prospective validation of prognostic scoring systems for ruptured abdominal aortic aneurysm (AAA) is lacking. This study assesses the validity of three established risk scores and a new prognostic index. METHOD: Patients admitted with ruptured AAA during a 26-month period (August 2002-December 2004) were recruited prospectively. The Glasgow Aneurysm Score (GAS), Hardman Index, Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) scores, and the Edinburgh Ruptured Aneurysm Score (ERAS) were recorded and related to outcome. RESULTS: During the study period, 111 patients were admitted with ruptured AAA. Of these, 84 (76%) underwent attempted operative repair and were included in the study; 37 (44%) died after operation. The GAS, Hardman Index, and the ERAS were statistically related to mortality. However, analysis by receiver-operator characteristic curve revealed the ERAS to have an area under the curve (AUC) of 0.72 (95% confidence interval [CI], 0.61-0.83). The vascular (V)-POSSUM and ruptured AAA (RAAA)-POSSUM models had an AUC of 0.70 (95% CI, 0.59-0.82). The Hardman Index and GAS had an AUC of 0.69 (95% CI, 0.57-0.80) and 0.64 (95% CI, 0.52-0.76), respectively. Although the V-POSSUM equation predicted mortality effectively (P = .086), the RAAA-POSSUM derivative demonstrated a significant lack of fit (P = .009). CONCLUSION: Prospective validation shows that the Hardman Index, GAS, and V-POSSUM and RAAA-POSSUM scores do not perform well as predictors for death after ruptured AAA. The ERAS accurately stratifies perioperative risk but requires further validation.     

Comparison of POSSUM scoring and the Hardman Index in selection of patients for repair of ruptured abdominal aortic aneurysm

BACKGROUND: The aim was to assess to what extent the POSSUM (Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity) and Hardman scoring systems were predictive of outcome after surgery for ruptured abdominal aortic aneurysm (RAAA). METHODS: From January 1990 to December 2001, 232 patients presented with RAAA. Forty-one were treated conservatively and all died; the remainder had emergency surgery. The case notes of all but three of these patients were reviewed retrospectively. POSSUM and Hardman scores were calculated and related to mortality. RESULTS: The mortality rate after emergency repair was 54 per cent (104 of 191). The physiology-only POSSUM score specific for RAAA and the Hardman Index score were both significantly associated with increased mortality after operation (P < 0.001). Most non-operated patients were in the highest risk bands. CONCLUSION: Both POSSUM and Hardman scoring systems predicted outcome after emergency surgery for RAAA. The Hardman Index was simpler to calculate, but POSSUM identified a higher number of patients at risk. Risk scoring may help identify patients with RAAA for whom surgery is futile.     

Risk-Adjusted Analysis of Outcomes Following Elective Open Abdominal Aortic Aneurysm Repair

The purpose of this study was to describe a method to analyze outcomes following open abdominal aortic aneurysm (AAA) repair while considering the variability in patients preoperative risk. Consecutive patients undergoing elective open infrarenal AAA repair during a 4-year period (2000-2003) were reviewed. Thirty-day or in-hospital mortality was the major outcome variable. Preoperative mortality risk was estimated for each patient using a validated scoring system that considers age, renal dysfunction, and coronary artery and cerebrovascular disease. A risk-adjusted cumulative sum method was used to compare observed versus predicted outcomes by assigning a risk-adjusted score, based on log-likelihood ratios, to each patient. These cumulative scores were sequentially plotted with preset control limits to allow for signaling when results were substantially different than expected (doubling or halving of odds ratios). Four hundred and sixty-three patients were studied with an overall early mortality rate of 4.5% (n=21). Patients were allocated to three different preoperative risk groups (low, n=89; medium, n=160; high, n=214) according to a medical comorbidity-based scoring system. Predicted (P) and observed (O) mortality rates for each group were as follows: low, 2.4% (P) and 2.2% (O); medium, 4.1% (P) and 4.4% (O); high, 9.3% (P) and 5.6% (O). The resulting risk-adjusted scores for each patient were plotted sequentially. This plot was flat for the first year and then adopted a negative slope crossing the lower control limit after 266 patients, indicating improved results compared to those expected. This coincided with the adoption of routine intraoperative cell saver use in our practice. This form of analysis allows for the prospective evaluation of results while considering patient-mix variabilities.Presented at the Twenty-ninth Annual Meeting of the Peripheral Vascular Surgery Society, Anaheim, CA, June 4-5, 2004.     

Endovascular ruptured abdominal aortic aneurysm repair (EVRAR): a systematic review.

BACKGROUND: To review evidence supporting the use of endovascular ruptured aneurysm repair (EVRAR) for treatment of ruptured abdominal aortic aneurysm (RAAA). METHODS: A systematic review of the medical literature was performed for relevant studies. We searched a number of electronic databases and hand-searched relevant journals until November 2006 to identify studies for inclusion. We considered studies in which patients with a confirmed ruptured abdominal aortic aneurysm were treated with EVRAR, which reported endpoints of mortality and major complications. RESULTS: There was 1 randomised controlled trial (RCT), 33 non-randomised case series (24 retrospective and 9 prospective) reports were identified comparing EVRAR (n=891) with conventional open surgical repair for the treatment of RAAA. Whilst no benefit in the primary outcome of mortality was noted in the only RCT, evidence from non-randomised studies suggest that EVRAR is feasible in selected patients, where it may be associated with a trend towards reductions in blood loss, duration of intensive care treatment, early complications, and mortality. CONCLUSIONS: For the treatment of symptomatic or ruptured abdominal aortic aneurysm, emergency endovascular repair (EVRAR) is feasible in selected patients, with early outcomes comparable to best conventional open surgical repair for the treatment of RAAA.     

Hospital variability in length of stay after coronary artery bypass surgery: results from the Society of Thoracic Surgeon's National Cardiac Database

BACKGROUND: There is growing interest in comparing resource, as well as patient outcome metrics among coronary artery bypass graft surgery (CABG) providers, yet few tools exist for adjusting these provider comparisons for patient case-mix. In this study, we aimed to define the magnitude of hospital variability in postoperative length of stay (PLOS) in contemporary practice and to determine the degree to which this variability was accounted for by differences in patient case-mix. We also sought to determine the relationship between hospitals' risk-adjusted PLOS and mortality outcomes. METHODS: We analyzed 496,797 isolated CABG procedures performed between January 1997 to January 2001 at 587 US hospitals participating in the Society of Thoracic Surgeon's National Cardiac Database. Logistic and linear regression were used to identify independent preoperative factors affecting a patient's likelihood for early discharge (PLOS < or = 5 day), prolonged stay (> 14 days), and overall PLOS. Hierarchical models were used to determine the degree to which hospital factors influenced PLOS beyond patient factors. RESULTS: Overall, 53% of CABG patients were discharged within 5 days of CABG, whereas 5% required prolonged (> 14 days) stays. More than 25 preoperative patient factors were independently associated with a patients' likelihood for early discharge and prolonged stay (model C index 0.70 and 0.75, respectively). After adjusting for patient factors, however, there remained wide unexplained variability among hospitals in PLOS and limited correlation between these PLOS metrics and hospitals' risk-adjusted mortality results (Spearman correlation coefficient -0.15 and 0.35). CONCLUSIONS: Our study provides a method for institutions to receive meaningful risk-adjusted bypass PLOS information. Given the marked variability among hospitals in CABG PLOS, institutions should consider benchmarking metrics of efficiency, as well as patient outcomes.     

POSSUM models in open abdominal aortic aneurysm surgery.

OBJECTIVES: This study evaluated the Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM), Portsmouth (P) POSSUM and Vascular (V) POSSUM. The primary aim was to assess the validity of these scoring systems in a population of patients undergoing elective and emergency open AAA repair. The secondary intention was in the event that these equations did not fit all patients with an aneurysm; a new model would be developed and tested using logistic regression from the local data (Cambridge POSSUM). METHODS: POSSUM data items were collected prospectively in a group of 452 patients undergoing elective and emergency open AAA repair over an eight-year period. The operative mortality rates were compared with those predicted by POSSUM, P-POSSUM, V-POSSUM and Cambridge POSSUM. RESULTS: All models except V-POSSUM (physiology only) showed significant lack of fit when predicting mortality after open AAA surgery. It was found that the locally generated single unified model (Cambridge POSSUM) could successfully describe both elective and ruptured AAA mortality with good discrimination (chi(2)=9.24, 7 d.f., p=0.236, c-index=0.880). CONCLUSIONS: POSSUM, V-POSSUM and P-POSSUM may not be robust tools for comparing mortality between populations undergoing elective and emergency open AAA repair as once thought. The development and successful validation of Cambridge POSSUM provides a unified model to describe both elective and emergency AAAs together and should be validated in other geographical settings.     

Predicting Outcome in Ruptured Abdominal Aortic Aneurysm: A Prospective Study of 100 Consecutive Cases

OBJECTIVES: Case selection for surgery in patients presenting with ruptured abdominal aortic aneurysms (RAAA) is often difficult. A previous retrospective review identified five pre-operative risk factors associated with mortality [J Vasc Surg 23 (1996) 123]. In this study we aimed to identify whether these criteria could be usefully applied prospectively in patients presenting with RAAA. METHODS: All patients presenting with RAAA from October 2000 to December 2002 were included. The criteria were recorded with the time they were available and the time surgery commenced. The decision to operate was made on clinical grounds and no patient was refused surgery on the basis of these criteria. RESULTS: One hundred consecutive patients were studied, median age 75 (range 54-94). The operative mortality was 32.9% (26/79 patients). Surgical mortality increased with the number of positive criteria and was 8% (2/24), 24% (7/29), 55% (11/20) and 100% (6/6) for scores, 0, 1, 2 and > or =3, respectively. Age and conscious level were available in every patient. However, an ECG, haemoglobin and creatinine results were only available in 94, 81, and 69%, respectively. CONCLUSIONS: The scoring system accurately predicted operative mortality. The score was available in the majority of cases and may help the surgeon give informed consent to patients and relatives prior to surgical intervention.     

Prediction of survival after 48-h of intensive care following open surgical repair of ruptured abdominal aortic aneurysm.

OBJECTIVE: To identify predictive factors for 30-day mortality after 48 h of maximal treatment in intensive care unit (ICU) after repair for ruptured abdominal aortic aneurysm (RAAA). DESIGN: Retrospective study in the ICU of the university central hospital. MATERIALS AND METHODS: Between 1999 and 2003, a total of 197 patients were admitted to emergency unit due to RAAA, and 185 of them underwent open surgical repair. A total of 138 patients survived at least 48-h and were included in a study to identify factors predictive of 30-day mortality by logistic regression analysis. RESULTS: Thirty-day mortality of all RAAA patients was 46% (87/197) whereas the 30-day mortality for those alive at 48 h was 22% (31/138). Forward stepwise multivariate logistic regression analysis revealed that only organ dysfunction by SOFA score (sequential organ failure assessment) at 48-h, preoperative Glasgow Aneurysm Score, and supra-renal clamping in operation were independent predictors of death. CONCLUSIONS: Degree of organ dysfunction by SOFA score was the best predictor of 30-day mortality in RAAA patients alive at 48-h after open surgical repair.     

In-hospital operative mortality of ruptured abdominal aortic aneurysm: a population-based analysis of 5593 patients in The Netherlands over a 10-year period.

OBJECTIVE: To determine the operative mortality of ruptured abdominal aortic aneurysm (RAAA) in The Netherlands. DESIGN: Retrospective population-based study of nation-wide in-hospital mortality of RAAA repair. METHODS: Data were obtained from a national registry for medical diagnosis and procedures. In-hospital mortality of RAAA repair, defined as death during hospital admission irrespective of the cause of death, was determined in the period 1991-2000. Variables of potential influence on in-hospital mortality, including age, gender, date of surgery and hospital type (0-399 beds, > or =400 beds or university hospitals) were studied in a multivariate analysis. RESULTS: The overall in-hospital mortality of RAAA repair in 5593 patients in the 10-year period was 41% (95% confidence interval: 40-42%). In the multivariate analysis, age and hospital type were the most important independent predictors for in-hospital mortality. Gender, year and season of surgery could not be identified as significant risk factors. CONCLUSIONS: Over a recent decade, in-hospital mortality of RAAA repair remained unchanged at 41%. Age and hospital class were the most important independent risk factors.     

Endovascular approaches to ruptured infrarenal aorto-iliac aneurysms

BACKGROUND: Ruptured abdominal aortoiliac aneurysms (RAAAs) carry a high mortality when treated by open surgical repair. Since 1994, we have employed endovascular approaches to treat this entity. METHODS: Patients with presumed RAAAs were treated with restricted fluid resuscitation (hypotensive hemostasis), rapid transport to the operating room, placement of a transbrachial or transfemoral guidewire under local anesthesia, and urgent arteriography. In patients with suitable anatomy, endovascular graft repair was performed. If the anatomy was unsuitable, standard open repair was performed. If the patient had circulatory collapse, proximal balloon control was employed. RESULTS: Of 31 patients managed in this fashion, 25 underwent endovascular graft repair. Six required open repair. Total operative mortality was 9.7% (3 patients). Only 10 patients required proximal balloon aortic control. CONCLUSIONS: Endovascular techniques (proximal balloon control and endografts) may improve treatment outcomes for RAAAs. Restricted resuscitation (hypotensive hemostasis) can be effective in the RAAA setting.     

Health-related quality of life in survivors of open ruptured abdominal aortic aneurysm repair: a matched, controlled cohort study

OBJECTIVE: The objective of this study was to document the health-related quality of life (HRQOL) for patients who survived operative repair of a ruptured abdominal aortic aneurysm (RAAA) and to compare this with a matched group of patients who survived elective operative repair of an abdominal aortic aneurysm (EAAA). METHODS: A matched, controlled cohort study of HRQOL was used to compare patients surviving RAAA with an EAAA control group. The study was conducted at two university-affiliated vascular tertiary care referral centers. Survivors of RAAA and EAAA during an 8.5-year period were identified and followed up. The RAAA and EAAA control patients were matched for age, serum creatinine concentration, gender, and duration of follow-up since surgery. HRQOL was measured with the Medical Outcomes Study Short Form-36 Health Survey (SF-36). Scores for the EAAA and RAAA cohorts were also compared with age-corrected SF-36 population scores. RESULTS: Of 267 patients operated for RAAA during the study period, 130 (49%) survived to hospital discharge. Death after discharge was documented in 35 patients, leaving a potential study population of 95 RAAA survivors. Thirteen were lost to follow-up, seven refused to participate, and four patients were not able to participate. The SF-36 was completed by 71 RAAA patients (75% of surviving RAAA patients). The 71 RAAA survivors and 189 EAAA control patients were similar for seven of eight domains of the SF-36: Physical Function, Role-Physical, Bodily Pain, General Health, Vitality, Mental Health, and Role-Emotional. There was also no difference in the Physical Health Summary and Mental Health Summary scores. The social function component of the SF-36 demonstrated a statistically significant decline in the EAAA group. Both the EAAA and RAAA SF-36 individual and summary scores compared favorably with population norms that were adjusted only for age. CONCLUSION: Long-term survivors of RAAA enjoy a HRQOL that does not differ significantly from EAAA survivors. Scores for both groups compare favorably with population scores adjusted only for age.     

Long-term survival and health-related quality of life of patients with ruptured abdominal aortic aneurysm.

INTRODUCTION: the outcome of ruptured abdominal aortic aneurysm (RAAA) patients is most frequently measured as operative or in-hospital mortality rate. However, survival alone is not an indicator of quality of the treatment. Assessment of quality of life (QoL) is used increasingly and is a relevant measure of outcome. OBJECTIVE:to assess long-term survival and QoL of patients undergoing repair of RAAA. DESIGN: follow-up study with cross-sectional QoL evaluation. MATERIALS AND METHODS: between 1996 and 2000, 199 of 220 patients with RAAA underwent surgery. Survivors were sent the generic the RAND 36-item Health Survey (RAND-36) self-administered questionnaire. RESULTS: total hospital mortality and operative mortality were 103 of 220 (47%) and 82 of 199 (41%). Of the 117 initial survivors, 21 were deceased at the time of the study. When compared to an age- and sex-adjusted general population, only physical functioning was significantly impaired (p=0.01) in the 82 of 93 (88%) RAAA survivors who responded. CONCLUSIONS: survivors after repair of RAAA had almost the same QoL as the norms of an age- and sex-adjusted general population, justifies an aggressive operative policy in RAAA.     

The effect of patient transfer on outcomes after rupture of an abdominal aortic aneurysm

OBJECTIVE: Centralization of vascular surgery services has resulted in patients being transferred longer distances for treatment of life-threatening conditions. The purpose of this study was to determine whether patient transfer adversely affects the survival of people with a ruptured abdominal aortic aneurysm (RAAA). METHODS: We performed a retrospective review of all patients undergoing attempted repair of an RAAA at our centre, over a recent 3.5-year period (August 2000-December 2003). Patients were divided into those presenting directly to our centre and those transferred from another hospital. The main outcome variable was in-hospital or 30-day mortality, with secondary variables including time to surgical treatment, mortality in the first 24 hours and length of hospitalization. RESULTS: Eighty-one patients (73% men) underwent attempted open repair of an RAAA at our centre during this period. Twenty-four patients (29.6%) presented directly to our hospital, while 57 (70.4%) were transferred from another institution. The overall mortality rate was 53%. Although transferred patients took twice as long as direct patients to get to the operating room (6.3 v. 3.2 h, p=0.03), there was no difference in mortality between the 2 groups (50% v. 54%, p=ns). However, deaths of transferred patients were more likely to occur in the first 24 postoperative hours, compared with direct patients (40% v. 33%, p<0.05). Neither mean intensive care unit stay (5.8 and 8.1 d) nor total hospitalization (20.9 and 18.8 d) differed between the 2 groups. CONCLUSIONS: Although the transfer of patients with RAAA results in a treatment delay, it does not adversely affect the already high mortality rates associated with this condition. These results may be attributed to a preselection of patients who are able to tolerate such a delay.     

Abdominal aortic aneurysm surgery in a district general hospital: a 15-years experience

The incidence of patients presenting with both ruptured abdominal aortic aneurysm (RAAA) and elective abdominal aortic aneurysm (EAAA) increases with age. The aim of our study was to find out the incidence of RAAA, age and sex groups of patients at risk, and 30-day all-cause perioperative mortality associated with RAAA as well as EAAA repair in a busy district general hospital over a 15-year time period. All patients operated for AAA during 1989-2003, both elective and ruptured, were included in the study. Patients who died in the community from RAAA were also included. The data were collected from the hospital information system, theater logbooks, intensive therapy unit records, postmortem register, and patients' medical notes. We divided the data for RAAA into two groups of 7.5 years each to see if there was any improvement over time in 30-day postoperative mortality. There were 816 cases of AAA, which included 468 RAAAs (57%) and 348 EAAAs (43%). Out of 468 RAAAs, 243 patients had emergency repair, of whom 213 were males. There were 201 patients who had RAAA postmortem (43%). Median age (range) was 73 (54-94) years in males and 77 (52-99) years in females, with a male-to-female ratio of 7:1. The peak incidence of RAAA was over 60 years of age in males and 70 years in females. Incidence of RAAA was 7.3/100,000/year in males and 5/100,000/year in females. For RAAA, 30-day perioperative mortality was 43% (105/243) while overall mortality was 70% (330/468), which includes deaths in the community. There was no improvement in 30-day mortality over time after comparing data for the first 7.5 years (50/115, 43.5%) with those for the second set of 7.5 years (55/128, 43%). There were 348 patients who had EAAA repair over the same period, comprising 282 males, with a male:female ratio of 4.3:1. The 30-day mortality in the elective group was 7.75%. Incidence and mortality of RAAA remain high. A high proportion of patients with AAA remain undiagnosed and die in the community. More lives may be saved if a screening program is started for AAA.     

Outcomes of endovascular treatment of ruptured abdominal aortic aneurysms

INTRODUCTION: The successful application of endovascular techniques for the elective repair of abdominal aortic aneurysms (AAAs) has stimulated a strong interest in their possible use in dealing with a long-standing surgical challenge: the ruptured abdominal aortic aneurysm (RAAA). The use of a conventional open procedure to repair ruptured aneurysms is associated with a high operative mortality of 45% to 50%. In this study, we evaluated the current frequency of endovascular repair of RAAAs in four large states and the impact of this technique on patient outcome. METHODS: We examined discharge data sets from 2000 through 2003 from the four states of California, Florida, New Jersey, and New York, whose combined population represents almost a third of the United States population. Proportions and trends were analyzed by chi2 analysis and continuous variables by the Student's t test. RESULTS: We found that since the year 2000, endovascular repair has begun to emerge as a viable treatment option for RAAAs, accounting for the repair of 6.2% of cases in 2003. During the same period, the use of open procedures for RAAAs declined. The overall mortality rate for the 4-year period was significantly lower for endovascular vs open repair (39.3% vs. 47.7%, P = .005). Moreover, compared with open repair, endovascular repair resulted in a significantly lower rate of pulmonary, renal, and bleeding complications. Survival after endovascular repair correlated with hospital experience, as assessed by the overall volume of elective and nonelective endovascular procedures. For endovascular repairs, mortality ranged from 45.9% for small volume hospitals to 26% for large volume hospitals (P = .0011). Volume was also a determinant of mortality for open repairs, albeit to a much lesser extent (51.5% for small volume hospitals, 44.3% for large volume hospitals; P < .0001). CONCLUSION: We observed a benefit to using endovascular procedures for RAAAs in institutions with significant endovascular experience; however, the analysis of administrative data cannot rule out selection bias as an explanation of better outcomes. These data strongly endorse the need for prospective studies to clarify to what extent the improved survival in RAAA patients is to be attributed to the endovascular approach rather than the selection of low-risk patients.     

An evaluation of existing risk stratification models as a tool for comparison of surgical performances for coronary artery bypass grafting between institutions

Objective: Risk stratification systems are used in cardiac surgery to estimate mortality risk for individual patients and to compare surgical performance between institutions or surgeons. This study investigates the suitability of six existing risk stratification systems for these purposes. Methods: Data on 5471 patients who underwent isolated coronary artery bypass grafting at two UK cardiac centres between 1993 and 1999 were extracted from a prospective computerised clinical data base. Of these patients, 184 (3.3%) died in hospital. In-hospital mortality risk scores were calculated for each patient using the Parsonnet score, the EuroSCORE, the ACC/AHA score and three UK Bayes models (old, new complex and new simple). The accuracy for predicting mortality at an institutional level was assessed by comparing total observed and predicted mortality. The accuracy of the risk scores for predicting mortality for a patient was assessed by the Hosmer-Lemeshow test. The receiver operating characteristic (ROC) curve was used to evaluate how well a system ranks the patient with respect to their risk of mortality and can be useful for patient management. Results: Both EuroSCORE and the simple Bayes model were reasonably accurate at predicting overall mortality. However predictive accuracy at the patient level was poor for all systems, although EuroSCORE was accurate for low to medium risk patients. Discrimination was fair with the following ROC areas: Parsonnet 0.73, EuroSCORE 0.76, ACC/AHA system 0.76, old Bayes 0.77, complex Bayes 0.76, simple Bayes 0.76. Conclusions: This study suggests that two of the scores may be useful in comparing institutions. None of the risk scores provide accurate risk estimates for individual patients in the two hospitals studied although EuroSCORE may have some utility for certain patients. All six systems perform moderately at ranking the patients and so may be useful for patient management. More results are needed from other institutions to confirm that the EuroSCORE and the simple Bayes model are suitable for institutional risk-adjusted comparisons.     

A meta-analysis of 50 years of ruptured abdominal aortic aneurysm repair

BACKGROUND: Operative repair of ruptured abdominal aortic aneurysm (RAAA) is associated with a high mortality rate but reported figures vary widely. The aim of this study was to estimate the operative mortality of RAAA repair and determine how it has changed over time. METHODS: A meta-analysis of all English language literature quoting figures for operative mortality of RAAA repair. RESULTS: The pooled estimate for the overall operative mortality rate of RAAA repair from 1955 to 1998 was 48 (95 per cent confidence interval 46 to 50) per cent. Meta-regression analysis of operative mortality over time demonstrated a constant reduction of approximately 3.5 per cent per decade (1954-1997) with an operative mortality rate estimate for the year 2000 of 41 per cent. Seventy-seven studies reported intraoperative mortality but, while this appears to have remained constant over time, there was evidence of the presence of publication bias in the subgroup of papers reporting this outcome. There was no evidence of publication bias for the overall operative mortality outcome. CONCLUSION: Contrary to the conclusion of recent studies, this paper demonstrates a gradual reduction with time in the operative mortality rate of RAAA repair.