Surgical repair of ruptured abdominal aortic aneurysms in the state of Maryland: factors influencing outcome among 527 recent cases

Evaluation of Survival Outcomes of Endovascular Versus Open Aortic Repair for Abdominal Aortic Aneurysms with a Big Data Approach

Abdominal aortic aneurysm (AAA) is a localized enlargement of the abdominal aorta. Once ruptured AAA (rAAA) happens, repairing procedures need to be applied immediately, for which there are two main options: open aortic repair (OAR) and endovascular aortic repair (EVAR). It is of great clinical significance to objectively compare the survival outcomes of OAR versus EVAR using randomized clinical trials; however, this has serious feasibility issues. In this study, with the Medicare data, we conduct an emulation analysis and explicitly "assemble" a clinical trial with rigorously defined inclusion/exclusion criteria. A total of 7826 patients are "recruited", with 3866 and 3960 in the OAR and EVAR arms, respectively. Mimicking but significantly advancing from the regression-based literature, we adopt a deep learning-based analysis strategy, which consists of a propensity score step, a weighted survival analysis step, and a bootstrap step. The key finding is that for both short- and long-term mortality, EVAR has survival advantages. This study delivers a new big data strategy for addressing critical clinical problems and provides valuable insights into treating rAAA using OAR and EVAR.

Volume-Outcome Association of Mitral Valve Surgery in the United States

Importance

Early surgery for severe primary degenerative mitral regurgitation is recommended, provided optimal outcomes are achievable. Contemporary national data defining mitral valve surgery volume and outcomes are lacking.

Objective

To assess national 30-day and 1-year outcomes of mitral valve surgery and define the hospital- and surgeon-level volume-outcome association with mitral valve repair or replacement (MVRR) in patients with primary mitral regurgitation.

Design, Setting, and Participants

This multicenter cross-sectional observational study used the Society of Thoracic Surgeons Adult Cardiac Surgery Database to identify patients undergoing isolated MVRR for primary mitral regurgitation in the United States. Operative data were collected from July 1, 2011, to December 31, 2016, and analyzed from March 1 to July 1, 2019, with data linked to the Centers for Medicare and Medicaid Services.

Main Outcomes and Measures

The primary outcome was 30-day in-hospital operative mortality after isolated MVRR for primary mitral regurgitation. Secondary outcomes were 30-day composite mortality plus morbidity (any occurrence of bleeding, stroke, prolonged ventilation, renal failure, or deep wound infection), rate of successful mitral valve repair of primary mitral regurgitation (residual mitral regurgitation of mild [1+] or better), and 1-year mortality, reoperation, and rehospitalization for heart failure.

Results

A total of 55 311 patients, 1094 hospitals, and 2410 surgeons were identified. Increasing hospital and surgeon volumes were associated with lower risk-adjusted 30-day mortality, lower 30-day composite mortality plus morbidity, and higher rate of successful repair. The lowest vs highest hospital volume quartile had higher 1-year risk-adjusted mortality (hazard ratio [HR], 1.61, 95% CI, 1.31-1.98), but not mitral reoperation (odds ratio [OR], 1.51; 95% CI, 0.81-2.78) or hospitalization for heart failure (HR, 1.25; 95% CI, 0.96-1.64). The surgeon-level 1-year volume-outcome associations were similar for mortality (HR, 1.60; 95% CI, 1.32-1.94) but not significant for mitral reoperation (HR, 1.14; 95% CI, 0.60-2.18) or hospitalization for heart failure (HR, 1.17; 95% CI, 0.91-1.50).

Conclusions and Relevance

National hospital- and surgeon-level inverse volume-outcome associations were observed for 30-day and 1-year mortality after mitral valve surgery for primary mitral regurgitation. These findings may help to define access to experienced centers and surgeons for the management of primary mitral regurgitation.

Impact of Mitral Valve Repair Case Volume on Postoperative Mortality - A Nationwide Korean Cohort Study

BACKGROUND

Although mitral valve repair is recommended over replacement due to better outcomes, repair rates vary significantly among centers. This study examined the effect of institutional mitral valve repair volume on postoperative mortality.Methods and Results:All cases of adult mitral valve repair performed in Korea between 2009 and 2016 were analyzed. The association between case volume and 1-year mortality was analyzed after categorizing centers according to the number of mitral valve repairs performed as low-, medium-, or high-volume centers (<20, 20-40, and >40 cases/year, respectively). The effect of case volume on cumulative all-cause mortality was also assessed. In all, 6,041 mitral valve repairs were performed in 86 centers. The 1-year mortality in low-, medium-, and high-volume centers was 10.1%, 8.7%, and 4.7%, respectively. Low- and medium-volume centers had increased risk of 1-year mortality compared with high-volume centers, with odds ratios of 2.80 (95% confidence interval [CI] 2.15-3.64; P<0.001) and 2.66 (95% CI 1.94-3.64; P<0.001), respectively. The risk of cumulative all-cause mortality was also worse in low- and medium-volume centers, with hazard ratios of 1.96 (95% CI 1.68-2.29; P<0.001) and 1.77 (95% CI 1.47-2.12; P<0.001), respectively.

CONCLUSIONS

Lower institutional case volume was associated with higher mortality after mitral valve repair. A minimum volume standard may be required for hospitals performing mitral valve repair to guarantee adequate outcome.

Association between institutional case volume and mortality following thoracic aorta replacement: a nationwide Korean cohort study

Background

The inverse relationship between case volume and postoperative mortality following high-risk surgical procedures have been reported. Thoracic aorta surgery is associated with one of the highest postoperative mortality. The relationship between institutional case volume and postoperative mortality in patients undergoing thoracic aorta replacement surgery was evaluated.

Methods

All thoracic aorta replacement surgeries performed in Korea between 2009 and 2016 in adult patients were analyzed using an administrative database. Hospitals were divided into low (< 30 cases/year), medium (30–60 cases/year), or high (> 60 cases/year) volume centers depending on the annual average number of thoracic aorta replacement surgeries performed. The impact of case volume on in-hospital mortality was assessed using the logistic regression.

Results

Across 83 hospitals, 4867 cases of thoracic aorta replacement were performed. In-hospital mortality was 8.6% (191/2222), 10.7% (77/717), and 21.9% (422/1928) in high, medium, and low volume centers, respectively. The adjusted risk of in-hospital mortality was significantly higher in medium (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.16–2.11, P = 0.004) and low volume centers (OR, 3.12; 95% CI, 2.54–3.85, P < 0.001) compared to high volume centers.

Conclusions

Patients who had underwent thoracic aorta replacement surgery in lower volume centers had increased risk of in-hospital mortality after surgery compared to those in higher volume centers. Our results may provide the basis for minimum case volume requirement or regionalization in thoracic aorta replacement surgery for optimal patient outcome.

Perioperative, Postoperative, and Long-Term Outcomes Following Open Surgical Repair of Ruptured Abdominal Aortic Aneurysm

We investigated factors that affected perioperative, postoperative, and long-term outcomes of patients who underwent open emergency surgical repair of ruptured abdominal aortic aneurysms (RAAA). All patients who underwent open emergency surgical repair from 1990 to 2011 were included (463 patients; 374 [81%] male; mean age 74.7 ± 8.7years). Logistic and Cox regression analyses were performed to explore the association of variables with outcomes. Preoperatively, median (interquartile range) hemoglobin was 11.2 (9.5-12.8) g/dL, and median creatinine level was 140 (112-177) µmol/L. Intraoperatively, the median operative time was 2.25 (2-3) hours, and median estimated blood loss was 1.5 (0.5-3) L; 250 (54%) patients required intraoperative inotropes, and a median of 6 (4-8) units of blood was transfused. Median length of hospital stay was 11 (7-20) days. In-hospital mortality rate was 35.6%, and 5-year mortality was 48%. Age, distance traveled, operation duration, postoperative myocardial infarction (MI), and multi-organ failure (MOF) were predictors of in-hospital mortality and long-term outcome. Additionally, postoperative acute renal failure predicted in-hospital mortality. In patients with RAAA undergoing open surgical repair, the strongest predictors of in-hospital mortality and long-term outcome were postoperative MOF and MI and operative duration.

[Patient volume and quality in surgery for abdominal aortic aneurysm]

BACKGROUND Patient volume is assumed to affect quality, whereby complex procedures are best performed by those who perform them frequently. We have conducted a systematic review of the research on the association between patient volume and quality of vascular surgery. In this article we describe the outcomes for abdominal aortic aneurysm surgery.MATERIAL AND METHOD We undertook systematic searches in relevant databases. We searched for systematic reviews, and randomised and observational studies. The search was concluded in December 2015. We have summarised the results descriptively and assessed the overall quality of the evidence.RESULTS Forty-six observational studies fulfilled our inclusion criteria. We found a possible association for both hospital and surgeon volume. Higher patient volume may possibly be associated with lower 30-day mortality and lower hospital mortality for both open and endovascular surgery. Although the association appears to apply to both elective and acute hospitalisations, there is greater uncertainty with regard to the most ill patients. For hospital volume there may also be fewer complications for open and endovascular surgery, as well as for all surgery assessed as a whole. We considered the evidence base to be medium to very low quality.INTERPRETATION We found a possible correlation between patient volume and quality indicators such as mortality and complications. It may be advantageous to allocate planned procedures to institutions and surgeons with high volume, while this is less certain with regard to acute hospitalisations.

Influence of Gender on Abdominal Aortic Aneurysm Repair in the Community

BACKGROUND

Women have been shown to experience inferior outcomes following intact and ruptured abdominal aortic aneurysm (AAA) treatment in endovascular aneurysm repair (EVAR) and open surgical repair (OSR) groups. The goal of our study was to compare gender-specific presentation, management, and early outcomes after AAA repair using a statewide registry.

METHODS

We utilized the Washington State's Vascular Interventional Surgical Care and Outcomes Assessment Program registry data collected in 19 hospitals from July 2010 to September 2013. Demographics, presentation, procedural data, and outcomes in elective and emergent AAA repair groups were analyzed.

RESULTS

We identified 1,231 patients (19.6% women) who underwent intact (86.4%) or ruptured AAA (13.6%) repairs. Nine thousand seventy-two (79.0%) patients had EVAR and 259 (21.0%) had OSR. Men and women were of equivalent age and had similar comorbidities, except that women had less coronary artery disease (P < 0.01) and were more likely to suffer from chronic obstructive pulmonary disease (P = 0.05). Women had smaller aneurysm diameters (5.8 ± 1.1 vs. 6.2 ± 1.8 cm, P < 0.01) at the time of presentation and men had slightly higher incidence of rupture at larger aneurysm size. Men were more likely to undergo EVAR, with significant differences in elective (82.1% vs. 74.1%, P = 0.01), but not ruptured repair. Women had significantly higher mortality rates following elective EVAR (3.1% vs. 0.6%, P = 0.01), but not after ruptured or elective open repair. Following elective EVAR, women were less likely to be discharged to home after longer hospital stays (3 vs. 2 days, P < 0.01).

CONCLUSIONS

Despite presentation at a similar age, with a smaller aneurysm diameter, and similar medical comorbidities, women experience substantially worse hospital outcomes primarily driven by elective endovascular procedures. Utilization of endovascular techniques in women still remains lower compared with men. Improvement of elective outcomes in women will likely depend on technical advancements in repair techniques and management strategies that may differ between genders.

Survival of Ruptured Abdominal Aortic Aneurysms in the West of Ireland: Do Prognostic Indicators of Outcome Exist?

Ruptured abdominal aortic aneurysm (RAAA) is a demanding vascular surgical problem and the cause of significant morbidity and mortality. The aim of this study was to identify prognostic factors that influence outcome. Over 6 years, 42 ruptured abdominal aortic aneurysms were operated on with a mean diameter of 7.2 cm. RAAA was defined as free intraperitoneal rupture. Data were collected retrospectively from hospital medical records. The male:female ratio was 8:1 and the mean age was 74 years (range 55–89). Fifteen were in hypovolemic shock and 27 patients were clinically stable. The perioperative mortality rate for the 15 shocked patients was 60% (9 patients) and the 1-year cumulative survival rate was 33%. The perioperative mortality rate for the 27 clinically stable patients was 40% (11 patients) and the 1-year cumulative survival rate was 56%. Survival curves were constructed for these groups to compare male versus female, age =70 versus age <70, shocked versus stable, and preoperative hemoglobin (Hb) =10 vs >10. No patient with preoperative cardiac arrest survived more than 24 hours. With VassarStats, the confidence interval for age, gender, hemodynamic status, and preoperative Hb were calculated. The standard weighted mean analysis by ANOVA gave a p value of <0.001. The overall 30-day mortality rate was 47% (20 of 42) and the 1-year mortality rate was 52% (22 of 42). Male patients over 70 years with RAAA in hypovolemic shock with low Hb have a higher 30-day mortality rate and few survive more than 1 year. The study suggests that each of these 4 parameters separately was not a strong prognostic indicator. Collectively, however, they strongly influence the prognosis of patients with RAAA. These findings strengthen the case for selective treatment for RAAA.

Transition from Open Surgery to Endovascular Treatment of Abdominal Aortic Aneurysm Rupture

BACKGROUND

To review the outcome before and after the implementation of protocol-based strategy for endovascular repair (EVAR) of abdominal aortic aneurysm rupture (rAAA).

METHODS

A retrospective analysis of prospectively collected data from a tertiary center during the period 2006-2011. Demographics, comorbidities, blood examinations, perioperative patients' status, and mortality rates were recorded. Univariate and multivariate analyses were used to assess the association of the type of the procedure with various factors.

RESULTS

A total of 58 (46 open surgical repair [OSR] and 12 EVAR) patients with mean age of 74 ± 17 years (91% males) were treated for rAAA. However, 39 (11 EVAR and 28 OSR) were operated with protocol-based strategy available. Total mortality rate was 52.6% (10 of 19) initially and 38.5% (15 of 39) after the implementation of a protocol-based strategy. During protocol-based treatment, the survival rate did not differ between the 2 procedures (7 of 11 EVAR and 17 of 28 OSR; P, ns). A 30-day mortality rate was associated with preoperative number of platelets (unadjusted P values, P = 0.013), age (odds ratio [OR] 0.796; 95% confidence interval [CI], 0.685-0.925; P = 0.003), and diastolic blood pressure (OR, 1.053; 95% CI, 1.016-1.093; P = 0.005). After mean follow-up of 48 ± 11 months, EVAR patients presented better outcome regarding mortality rate (36% OSR vs. 0% EVAR; P = 0.0464).

CONCLUSIONS

After the adoption of an available rEVAR protocol-based strategy, EVAR and OSR were equally effective during postoperative 30 days. The role of hypotension and age is important on poor outcomes during this period. However, after midterm follow-up, EVAR demonstrates better survival rates than OSR.

Abdominal Aortic Aneurysm Repair in Octogenarians versus Younger Patients in a Tertiary Referral Center

Operative survival is as high as 96% for elective abdominal aortic aneursym (AAA) repair but as low as 10% for emergency repair. Our primary aim was to compare elective AAA repair in octogenarians with nonoperative management. Our secondary aim was to compare octogenarians with their younger counterparts.

From 1998 to 2003, 180 patients with AAA were treated operatively or nonoperatively. Factors determining treatment included American Society of Anesthesiologists grade ≥ 4, inoperable malignancy, New York Heart Association class III, forced expiratory volume in 1 second < 35%, creatinine > 6.0 mg/dL, and patient and family choice. A parallel-group observational study was performed to assess age and treatment effects on outcome.

Seventy (39%) patients were repaired electively, 68 (38%) were managed nonoperatively, and 42 (23%) underwent emergency repair. Fifty-nine (33%) were octogenarians.

The octogenarian 5-year survival rate was 20% following emergency repair, 42% if treated nonoperatively, and 83% following elective repair. Younger cohort rates were 55% (emergency), 44% (nonoperative), and 76% (elective).

The octogenarian mean expansion rate was 0.26 cm/yr in those treated nonoperatively and 1.04 cm/yr in confirmed rupture. Rupture rate was related to expansion rate (95% confidence interval [CI] 0.06–0.59, r = .35, p = .01). The rates in the younger subgroup were 0.32 cm/yr and 1.14 cm/yr (95% CI −0.021–0.672}, r = .37, p = .03).

The octogenarian survival rate was highest following elective repair. Rupture was closely correlated with aneurysm expansion. Screening should reduce the incidence of octogenarian rupture of AAA and identify those patients most suitable for nonoperative management.

Amsterdam Acute Aneurysm Trial Collaborators. Amsterdam Acute Aneurysm Trial: Background, Design, and Methods

The objective of the Amsterdam Acute Aneurysm Trial is to study the combined outcome of conventional emergency surgery versus endovascular treatment for ruptured abdominal aortic aneurysms. The design used was a multicenter randomized clinical trial conducted in two university hospitals and one teaching hospital in the Amsterdam region. The study included all patients with a ruptured abdominal aneurysm who were eligible for endovascular and conventional surgery. The primary end points were combined mortality and severe morbidity. The secondary end points were quality of life and cost-effectiveness. The background, design, and methods of this trial are presented, and the ethical and legal issues of this type of research are discussed.

Subspecialization within pediatric surgical groups in North America

PURPOSE

The purpose of this study was to assess the current status of subspecialization in North American pediatric surgical practices and to evaluate factors associated with subspecialization.

METHODS

A survey was sent to each pediatric surgical practice in the United States and Canada. For each of 44 operation types, ranging in complexity and volume, the respondents chose one of the following responses: 1. everyone does the operation; 2. group policy--only some surgeons do the operation; 3. group policy--anyone can do it but mentorship required; 4. only some do it due to referral patterns; 5. no one in the group does it. Association of various factors with degree of subspecialization was analyzed using nonparametric statistics with p<0.05 considered significant.

RESULTS

Response rate was 70%. There was significant variability in subspecialization among groups. Factors found to be significantly associated with increased subspecialization included free-standing children's hospitals, pediatric surgery training programs, higher number of surgeons, higher case volume, and greater volume of tertiary/quaternary cases.

CONCLUSIONS

There is wide variation in the degree of subspecialization among North American pediatric surgery practices. These data will help to inform ongoing debate around strategies that may be useful in optimizing pediatric surgical care and patient outcomes in the future.

Implantation of 3D-Printed Patient-Specific Aneurysm Models into Cadaveric Specimens: A New Training Paradigm to Allow for Improvements in Cerebrovascular Surgery and Research

Aim. To evaluate the feasibility of implanting 3D-printed brain aneurysm model in human cadavers and to assess their utility in neurosurgical research, complex case management/planning, and operative training. Methods. Two 3D-printed aneurysm models, basilar apex and middle cerebral artery, were generated and implanted in four cadaveric specimens. The aneurysms were implanted at the same anatomical region as the modeled patient. Pterional and orbitozygomatic approaches were done on each specimen. The aneurysm implant, manipulation capabilities, and surgical clipping were evaluated. Results. The 3D aneurysm models were successfully implanted to the cadaveric specimens' arterial circulation in all cases. The features of the neck in terms of flexibility and its relationship with other arterial branches allowed for the practice of surgical maneuvering characteristic to aneurysm clipping. Furthermore, the relationship of the aneurysm dome with the surrounding structures allowed for better understanding of the aneurysmal local mass effect. Noticeably, all of these observations were done in a realistic environment provided by our customized embalming model for neurosurgical simulation. Conclusion. 3D aneurysms models implanted in cadaveric specimens may represent an untapped training method for replicating clip technique; for practicing certain approaches to aneurysms specific to a particular patient; and for improving neurosurgical research.

Can experience improve hospital management?

BACKGROUND

Experience curve effects were first observed in the industrial arena as demonstrations of the relationship between experience and efficiency. These relationships were largely determined by improvements in management efficiency and quality of care. In the health care industry, volume-outcome relationships have been established with respect to quality of care improvement, but little is known about the effects of experience on management efficiency. Here, we examine the relationship between experience and hospital management in Japanese hospitals.

METHODS

The study sample comprised individuals who had undergone surgery for unruptured abdominal aortic aneurysms and had been discharged from participant hospitals between April 1, 2006 and December 31, 2008. We analyzed the association between case volume (both at the hospital and surgeon level) and postoperative complications using multilevel logistic regression analysis. Multilevel log-linear regression analyses were performed to investigate the associations between case volume and length of stay (LOS) before and after surgery.

RESULTS

We analyzed 909 patients and 849 patients using the hospital-level and surgeon-level analytical models, respectively. The odds ratio of postoperative complication occurrence for an increase of one surgery annually was 0.981 (P < 0.001) at the hospital level and 0.982 (P < 0.001) at the surgeon level. The log-linear regression analyses showed that shorter postoperative LOS was significantly associated with high hospital-level case volume (coefficient for an increase of one surgery: -0.006, P = 0.009) and surgeon-level case volume (coefficient for an increase of one surgery: -0.011, P = 0.022). Although an increase of one surgery annually at the hospital level was statistically associated with a reduction of preoperative LOS by 1.1% (P = 0.006), there was no significant association detected between surgeon-level case volume and preoperative LOS (P = 0.504).

CONCLUSION

Experience at the hospital level may contribute to the improvement of hospital management efficiency.

Recent risk factors for open surgical mortality in patients with ruptured abdominal aortic aneurysm

Aim

We examined recent relevant prognostic factors for the outcome of open surgical treatment of ruptured abdominal aortic aneurysm.

Methods

Between 2006 and 2012, 35 patients received emergency open surgical treatment for ruptured abdominal aortic aneurysm at our institute. We reviewed ambulance activity logs and clinical records of 34 infrarenal ruptured abdominal aortic aneurysm patients retrospectively. Univariate and multivariate logistic regression analyses were carried out to identify risk factors for surgical outcomes.

Results

Eight patients died during surgery or within a few hours following surgery completion. Through univariate analysis, body mass index, serum lactate level, arterial blood pH, base excess, platelet count, prothrombin time-international normalized ratio, activated partial thromboplastin time, type of ruptured aneurysm, response to i.v. fluid resuscitation within 2,000 mL in the initial therapy, and volume of blood loss during surgery were detected to be significant variants. Multivariate logistic regression analysis revealed the patients who were hemodynamically stabilized after primary volume loading had a 13.2 times higher possibility of survival. Body mass index, high serum lactate level, and volume of blood loss were also found to be independent risk factors of mortality.

Conclusion

The risk factors of open surgical ruptured abdominal aortic aneurysm repair, body mass index, lactate level, volume of intraoperative blood loss, and response to initial 2,000 mL fluid resuscitation were correlated to survival.

Derivation and validation of a practical risk score for prediction of mortality after open repair of ruptured abdominal aortic aneurysms in a US regional cohort and comparison to existing scoring systems

OBJECTIVE

Scoring systems for predicting mortality after repair of ruptured abdominal aortic aneurysms (RAAAs) have not been developed or tested in a United States population and may not be accurate in the endovascular era. Using prospectively collected data from the Vascular Study Group of New England (VSGNE), we developed a practical risk score for in-hospital mortality after open repair of RAAAs and compared its performance to that of the Glasgow aneurysm score, Hardman index, Vancouver score, and Edinburg ruptured aneurysm score.

METHODS

Univariate analysis followed by multivariable analysis of patient, prehospital, anatomic, and procedural characteristics identified significant predictors of in-hospital mortality. Integer points were derived from the odds ratio (OR) for mortality based on each independent predictor in order to generate a VSGNE RAAA risk score, which was internally validated using bootstrapping methodology. Discrimination and calibration of all models were assessed by calculating the area under the receiver-operating characteristic curve (C-statistic) and applying the Hosmer-Lemeshow test.

RESULTS

From 2003 to 2009, 242 patients underwent open repair of RAAAs at 10 centers. In-hospital mortality was 38% (n = 91). Independent predictors of mortality included age >76 years (OR, 5.3; 95% confidence interval [CI], 2.8-10.1), preoperative cardiac arrest (OR, 4.3; 95% CI, 1.6-12), loss of consciousness (OR, 2.6; 95% CI, 1.2-6), and suprarenal aortic clamp (OR, 2.4; 95% CI, 1.3-4.6). Patient stratification according to the VSGNE RAAA risk score (range, 0-6) accurately predicted mortality and identified those at low and high risk for death (8%, 25%, 37%, 60%, 80%, and 87% for scores of 0, 1, 2, 3, 4, and ≥5, respectively). Discrimination (C = .79) and calibration (χ(2) = 1.96; P = .85) were excellent in the derivation and bootstrap samples and superior to that of existing scoring systems. The Glasgow aneurysm score, Hardman index, Vancouver score, and Edinburg ruptured aneurysm score correlated with mortality in the VSGNE cohort but failed to identify accurately patients with a risk of mortality >65%.

CONCLUSIONS

Existing scoring systems predict mortality after RAAA repair in this cohort but do not identify patients at highest risk. This parsimonious VSGNE RAAA risk score based on four variables readily assessed at the time of presentation allows accurate prediction of in-hospital mortality after open repair of RAAAs, including identification of those patients at highest risk for postoperative mortality.

Outcome after open repair of ruptured abdominal aortic aneurysm in patients>80 years old: a systematic review and meta-analysis

BACKGROUND

The role of open repair in the management of ruptured abdominal aortic aneurysm (RAAA) in patients>80 years old is questioned by the perceived high operative risk of these patients. This issue has been investigated in the present meta-analysis of observational studies.

METHODS

Studies on open repair of RAAA in patients>80 years old were identified in July 2010. The immediate and intermediate results were expressed as pooled proportions with 95% confidence interval (95% CI). Linear regression and meta-regression were performed to evaluate the impact of variables on the immediate postoperative mortality.

RESULTS

Pooled analysis of 29 studies showed that the risk of immediate postoperative mortality in patients>80 years old was significantly higher than in younger patients (risk ratio 1.440, 95%CI 1.365-1.519, I2 36.8%, P=0.002; risk difference 19.4%, 95% CI 16.4-22.4%, I2 38.8%, P=0.019). Pooled analysis of 36 studies showed an immediate postoperative mortality rate of 59.2% (95% CI 55.7-62.5, I2 35.62). Immediate postoperative mortality in patients<80 years old positively correlated with that of patients>80 years old (rho: 0.686, P<0.0001). Intermediate survival data of 111 operative survivors were available from six studies, and their pooled survival rates at 1-, 2-, and 3-year were 82.4, 75.6, and 68.7%, respectively.

CONCLUSIONS

Immediate and intermediate survival rates of patients>80 years old after open repair of RAAA are acceptable. These findings suggest a more confident approach toward emergency repair of RAAA in the very elderly.

Ruptured abdominal aortic aneurysms: role of endovascular therapy

Ruptured abdominal aortic aneurysms historically have high mortality rates. Despite improvements in many open surgical techniques and perioperative care, these mortality rates have not significantly changed. Some of the reasons for the high mortality rates include the excessive blood loss and hypothermia that occur during open operative repair. The blood loss and hypothermia, combined with resuscitative dilutional coagulopathy, can lead to an irreversible spiraling coagulopathy that ultimately ends in the patient's demise. The availability of endovascular approaches to treat abdominal aortic aneurysms in the early 1990s offered an opportunity to substantially alter the treatment outcomes of ruptured abdominal aortic aneurysms. Endovascular repair offers many advantages, including rapid aortic control under local anesthesia, as well as an opportunity to limit the hypothermia and blood loss that occur with an open abdomen. This article will review the endovascular management of ruptured abdominal aortic aneurysms and describe the endovascular techniques for safe and effective treatment. Mt Sinai J Med 77:250-255, 2010. (c) 2010 Mount Sinai School of Medicine.

Effect of hospital and surgeon volume on patient outcomes following treatment of abdominal aortic aneurysms: a systematic review

OBJECTIVES

This systematic review assessed the efficacy of centralisation for the treatment of unruptured and ruptured abdominal aortic aneurysms. Patient outcomes achieved by low and high volume hospitals/surgeons, including morbidity, mortality and length of hospital stay, were used as proxy measures of efficacy.

DESIGN

Systematic review was designed to identify, assess and report on peer-reviewed articles reporting outcomes from unruptured and ruptured abdominal aortic aneurysms. No language restriction was placed on the databases searched.

MATERIALS

Only peer-reviewed journals articles were included.

METHODS

To ensure the contemporary nature of this review, only studies published between January 1997 and June 2007 were sought. Studies were included if they reported on at least one volume type and patient outcome.

RESULTS

Twenty two studies were included in this review. In the majority of group assessments, the number of studies reporting statistical significance was similar to the number of studies reporting no statistical significance.

CONCLUSION

The paucity of studies reporting statistically significant results demonstrates that although this evidence exists, its potential to be overstated must also be taken into account when drawing conclusions as to its efficacy for twenty first century healthcare systems.

Outcome in patients requiring renal replacement therapy after open surgical repair for ruptured abdominal aortic aneurysm

OBJECTIVE

To determine the relationship between postoperative renal replacement therapy (RRT) and patient survival after open surgical repair (OR) of ruptured abdominal aortic aneurysm (rAAA).

METHODS

A retrospective review of consecutive patients who underwent OR for rAAA repair between January 2002 and July 2008 was performed. Early (<30 days) and late (>30 days) outcomes were assessed.

RESULTS

A total of 94 patients (69 men; median [range] age 73.8 [56-89] years) underwent OR of rAAA (infrarenal = 78, juxtarenal = 15, and suprarenal = 1). In-hospital mortality rate was 40% and mean (range) length of intensive care unit (ICU) stay was 9.3 (0-56) days. A total of 23 (24%) patients required postoperative RRT. In-hospital mortality rate was significantly higher (RRT: 87% (20 of 23) vs no RRT: 18 of 71 (25%), P < .0001) and ICU stay significantly longer (RRT: mean (range) days; 14.8 (1-44) vs no RRT: 7.5 (0-56), P = .04) in the RRT patients. On multivariate analysis, RRT (P = .0053) and/or inotropic support (P = .0033) were independent risk factors for death within 30 days of the index procedure.

CONCLUSIONS

Renal replacement therapy following OR of rAAA is an independent risk factor for mortality.

Systematic review and meta-analysis of sex differences in outcome after intervention for abdominal aortic aneurysm

Background

The aim of this study was to assess possible differences in mortality between men and women with an abdominal aortic aneurysm (AAA) treated either by elective repair or following aneurysm rupture.

Methods

A systematic literature search was performed using the MEDLINE, Cochrane and Embase databases. Data were analysed by means of bivariate random-effects meta-analysis. Data were pooled and odds ratios (ORs) calculated for women compared with men.

Results

Sixty-one studies (516 118 patients) met the predetermined inclusion criteria. Twenty-six reported on elective open AAA repair, 21 on elective endovascular repair, 25 on open repair for ruptured AAA and one study on endovascular repair for ruptured AAA. Mortality rates for women compared with men were 7·6 versus 5·1 per cent (OR 1·28, 95 per cent confidence interval (c.i.) 1·09 to 1·49) for elective open repair, 2·9 versus 1·5 per cent (OR 2·41, 95 per cent c.i. 1·14 to 5·15) for elective endovascular repair, and 61·8 versus 42·2 per cent (OR 1·16, 95 per cent c.i. 0·97 to 1·37) in the group that had open repair for rupture. The group that had endovascular repair for ruptured AAA was too small for meaningful analysis.

Conclusion

Women with an AAA had a higher mortality rate following elective open and endovascular repair.

Population-based outcomes following endovascular and open repair of ruptured abdominal aortic aneurysms

PURPOSE

To evaluate national outcomes after endovascular and open surgical repair of ruptured abdominal aortic aneurysms (rAAA).

METHODS

The Nationwide Inpatient Sample was interrogated to identify all repairs between 2000 and 2005 for rAAA based on ICD-9 codes. In the study period, 2323 patients (1794 men; median age 75 years, range 45-98) with rAAAs had endovascular repair, while 26,106 patients (20,311 men; median age 73 years, range 22-99) had an open procedure. Outcomes included in-hospital mortality, length of stay (LOS), complications, and hospitalization charge. A secondary analysis was performed to compare outcomes from low-, medium-, and high-volume institutions based on annual rAAA repair volume.

RESULTS

Patients in the endovascular group were significantly older (p<0.05). Mortality was 41% overall: 33% and 41% for endovascular versus open repair, respectively (p<0.001). Mortality after endovascular repair was lower than open surgery for patients >or=70 years (36% versus 47%, p<0.001), but not for those <70 years (24% versus 30%, p = 0.15). LOS was shorter after endovascular repair (7 versus 9 days, p<0.001). Respiratory complications (8% versus 4%, p<0.05) and acute renal failure were more common following open repair (30% versus 23%, p<0.01). Costs were similar (endo $73,590 versus open $67,287, p = 0.15). Mortality decreased as hospital surgical volume increased (low 44%, medium 39%, high 38%; p<0.001). Over time, endovascular repair utilization increased more rapidly at high-volume centers, and a lower mortality was seen with endovascular repair at high-volume compared to low-volume hospitals (22% versus 44%, p<0.001). Multivariate predictors of mortality were age, female gender, lower hospital surgical volume, open repair, and year of surgery.

CONCLUSION

This population-based study found that mortality associated with rAAAs may be improved by the performance of endovascular repair, especially in older patients. Mortality after rAAA for both endovascular and open repairs was also lower at high-volume institutions.

The future of EVAR in the management of ruptured AAAs

Endovascular repair of ruptured abdominal aortic aneurysms is an evolving technique. Data from nonrandomized series suggest that it may be beneficial in selected patients. In the next few years, a number of large randomized clinical trials will clarify its role. Issues regarding anatomical suitability, techniques, perioperative care, and service provision need to be addressed in order to optimize outcomes.

Morphological aspects of mural thrombi deposition residual lumen route in infrarenal abdominal aorta aneurisms

PURPOSE

To assess the most frequent deposition site of mural thrombi in infrarenal abdominal aorta aneurisms, as well as the route of the residual lumen.

METHODS

Assessment of CT scan images from 100 patients presenting asymptomatic abdominal aorta aneurism, and followed at HC-FMRP-USP.

RESULTS

In 53% of the cases the mural thrombus was deposited on the anterior wall; from these, in 22%, the residual lumen described a predominantly right sided route; in 22%, a left sided route; on the mid line in 5%; and crossing over the mid line in 1%. In 23%, the deposition of thrombi was concentric. In 11% it occurred on the posterior wall; from these, in 5%, the route of the residual anterior lumen was predominantly right sided; in 5%, left sided; and crossed over the mid line in 1%. In 13% complex morphological deposition patterns were found.

CONCLUSION

Mural thrombi formation was predominantly found on the anterior wall of the aneurismatic mass, with the route of the residual lumen projecting towards the posterior wall.

Effect of Patient Transfer on Outcomes after Open Repair of Ruptured Abdominal Aortic Aneurysms

Patients with ruptured abdominal aortic aneurysms (RAAAs) benefit from treatment in high-volume facilities. This study explored the effect of patient transfer on outcomes and the relationship between hemodynamic status and mortality. We performed a retrospective review of 83 consecutive patients who had open repair for RAAA at a single tertiary facility. The patients were divided into two groups based on arrival in the local emergency department, “local” ( n = 44) versus “transfer” ( n = 39) from an outside institution, and into three categories of hemodynamic status: (a) no obtainable blood pressure, “pulseless”; (b) requiring vasopressor support, “pressors”; and (c) no vasopressor support, “no pressors.” Thirty-day mortality was 21.4%. There was no difference in mortality between the local (18.2%) and transfer (25.6%) patients ( p = .41). There were no deaths during transfer. There was no difference in the hemodynamic status of the transfer versus the local group ( p = .34). The mortality by category was pulseless, 100% (3 of 3); pressors, 71.4% (10 of 14); and no pressors, 7.6% (5 of 66) ( p < .0001). Actuarial survival was 66%, 64%, and 62% at 1, 3, and 5 years, respectively. Patient transfer does not adversely affect mortality after RAAA repair. Patients without a palpable pulse and those requiring hemodynamic support have a significantly higher mortality.

Systemic Administration of Heparin Intraoperatively in Patients Undergoing Open Repair of Leaking Abdominal Aortic Aneurysm May Be Beneficial and Does Not Cause Problems

The aim of this study was to investigate whether intravenous heparin administration was associated with a reduction in perioperative mortality and late distal thrombectomy in patients with ruptured abdominal aortic aneuryms (AAAs). One hundred thirty-one patients had repair of ruptured AAA between January 1999 and January 2004. Sixty-three received heparin according to the consultant's preference at the time of the operation. Data were prospectively collected, and multivariate analysis was performed for independent predictive factors. Thirty-day mortality was 29%. Patients receiving heparin had lower perioperative mortality (16% vs 42%; p = .001). Heparin administration was not associated with increased hemorrhage or transfusion. Multivariate analysis confirmed that heparin administration was independently predictive of survival ( p = .036). Other factors found to reduce survival were age ( p = .023), smoking ( p = .042), and systolic blood pressure (< 100 mmHg) at presentation ( p = .045). Fewer patients had thrombectomy after heparin (8% vs 12%), but this was not statistically significant. Perioperative complications were similar in both groups. The administration of systemic heparin before the clamp is applied to leaking aneurysms does not appear to increase hemorrhage and subsequent mortality and may reduce the need for early thrombectomy.

Prediction of outcome after abdominal aortic aneurysm rupture

BACKGROUND

Most vascular surgeons practice a selective policy of operative intervention for patients with ruptured abdominal aortic aneurysm (AAA). The evidence on which to justify operative selection remains uncertain. This review examines the prediction of outcome after attempted open repair of ruptured AAA.

METHODS

The Medline and EMBASE databases and Cochrane Database of Systematic Reviews were searched for clinical studies relating to the prediction of outcome after ruptured AAA. Reference lists of relevant articles were also reviewed.

RESULTS

The last 20 years has seen >60 publications considering variables predictive of outcome after AAA rupture. Four predictive scoring systems are reported: Hardman Index, Glasgow Aneurysm Score, Physiological and Operative Severity Score for Enumeration of Mortality and Morbidity (POSSUM), and the Vancouver Scoring System. No scoring system has been shown to have consistent or absolute validity. Of the remaining data, there are no individual or combination of variables that can accurately and consistently predict outcome.

CONCLUSIONS

Little robust evidence is available on which to base preoperative outcome prediction in patients with ruptured AAA. Experienced clinical judgement will remain of foremost importance in the selection of patients for ruptured AAA repair.

A decade of change in abdominal aortic aneurysm repair in the United States: Have we improved outcomes equally between men and women?

OBJECTIVES

Abdominal aortic aneurysm (AAA) repair has undergone vast changes in the last decade. We reviewed a national database to evaluate the effect on utilization of services and rupture rates.

METHODS

From the Centers for Medicare Services (CMS), a 5% inpatient sample was obtained for 1994 to 2003 as beneficiary encrypted files (5% BEF) and as a limited data set file after 2001. Files were translated into Microsoft Access by using a custom program. Queries were performed using International Classification of Diseases (9th Revision) (ICD-9) diagnosis codes 441.3 (ruptured AAA) or 441.4 (non-ruptured AAA) and ICD-9 procedure codes 38.34, 38.36, 38.44, 38.64, 39.25, 39.52 for open, and 39.71 (available after October 2000) for endovascular repair. The 5% BEF totals were multiplied by 20 to calculate yearly volumes. Total cases were divided into the yearly CMS population of elderly Medicare recipients for repair rates per capita and are reported as cases per 100,000 elderly Medicare recipients. Statistics were performed using chi2, Student's t test, nonparametric tests, and multiple regression analysis; P < or = .05 was considered significant.

RESULTS

Elective AAA repairs declined from 94.4/100,000 in 1994 to 87.7/100,000 in 2003. AAA rupture surgery declined from 18.7/100,000 (1994) to 13.6/100,000 (2003). Rupture repairs from 1994 to 2003 decreased by 29% for men and by 12% for women (P < .001). Rupture mortality has not changed, but the average is significantly higher for women at 52.8%, with men averaging 44.2% (P < .001). Mortality for elective AAA repair has decreased from 5.57% (1994) to 3.20% (2003) in men (P < .001) and from 7.48% (1994) to 5.45% (2003) in women (P < .001). Multivariate analysis demonstrated increasing age, female sex, and open surgery (vs endovascular) were significant predictors of elective and ruptured AAA repair mortality. For 2003 elective AAA repairs, the average length of stay was 6.9 days in men and 8.9 days in women (P < .01) For 2003, men were more likely to be discharged to home after rupture (32.9% of men vs 23.3% of women; P < .001) and elective repair (84.5% of men vs 70.1% of women; P < .001).

CONCLUSIONS

Improvements in AAA management in the last decade have decreased aneurysm-related deaths and reduced the incidence of aneurysm ruptures, with a lower utilization of services. Women, however, continue to have a consistently higher mortality for open and ruptured AAA repair and are less likely to return to home after either.

Curative rectal cancer surgery in a low-volume hospital: a quality assessment

AIMS

Hospital volume or caseload is often used as a surrogate measure for quality of care in rectal cancer treatment. The aim of this study was to assess outcome in a low-volume hospital and secondly to examine the impact of surgeon volume on the results.

METHODS

A retrospective review of 131 patients' charts identified 102 patients receiving apparently curative resections for rectal cancer in the period 1993-2002. Our study population did not differ significantly from the national average except for shift towards more advanced Dukes stage (p=0.00) and a higher rate of node positive patients at time of diagnosis (p=0.00).

RESULTS

There were no significant differences from the national outcome results, neither in perioperative mortality or complications, nor 5-year survival or local recurrences. Thirteen different on-staff surgeons performed rectal cancer surgery in our hospital in the decade, and median annual caseload was four. We detect a difference in 5-year survival when grouping the surgeons by annual caseload, but the significance is inconclusive. It is, however, interesting that in 85% of the resections, two or more certified gastrointestinal surgeons with specific training were involved. A relatively high number (9%) of discrepancies between the Norwegian Rectal Cancer Registry (NRCR) database and the local hospital database were identified.

CONCLUSION

Adequate results for surgical outcome can be achieved in a low-volume hospital. Surgeon volume showed inconclusive impact for our results of outcome. A local quality initiative is justified in addition to national registries.

The Amsterdam Acute Aneurysm Trial: Suitability and Application Rate for Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

PURPOSE

To evaluate anatomical suitability and application rate for endovascular repair of patients with a ruptured abdominal aortic aneurysm (RAAA).

METHODS

The Amsterdam Acute Aneurysm trial is a multicenter randomised trial comparing open with endovascular treatment in patients with a RAAA (International Standard Randomized Controlled Trial Number (ISRCTN) 66212637). Between April 2004 and January 2006, all consecutive patients with clinical suspicion of a RAAA at presentation were assessed prospectively. Anatomical suitability for endovascular repair was based on use of an aorto-uni-iliac endovascular graft and assessed in patients with a proven aortic rupture on CT angiography (CTA).

RESULTS

In 128/256 patients, presenting with clinical suspicion of a ruptured aneurysm, RAAA was diagnosed. 105 patients were brought to a trial center and CTA confirmed RAAA in 83 patients. In 38 of 83 patients (45.8%) with positive CTA, the anatomy of the aorta and iliac arteries was considered suitable for endovascular repair. Exclusion from endovascular repair was due to unsuitable infrarenal neck or iliac anatomy (37 and 8 patients respectively). Overall, endovascular treatment was applicable in 38/128 patients (29.7%) with a RAAA in the Amsterdam region and in 38 out of 105 patients (35.5%) admitted to the trial centers.

CONCLUSION

In this prospective cohort of all patients with a RAAA in the Amsterdam Acute Aneurysm Trial region, the suitability for endovascular repair in patients with a RAAA confirmed on CTA is 45.8%, but the application rate was lower.

How does the participation of a resident surgeon in procedures for small intracranial aneurysms impact patient outcome?

Object

In this paper the authors' goal was to evaluate whether resident neurosurgeons participating in entry-level aneurysm surgery have a negative impact on patient outcomes.

Methods

The authors searched the database for entry-level aneurysm surgeries (that is, those ≤ 10 mm and located in the internal carotid artery [beyond the paraclinoid segment] and middle cerebral artery) performed in 1991 through 2005. The presence or absence of an advanced resident (in his/her last 3 years of residency) was noted. The analysis was examined in 3-year quintiles.

A total of 355 cases (196 with resident participation and 159 without) were evaluated. Permanent adverse outcomes were seen in 11 patients (3.1% of the total study population), all due to branch artery occlusion. The incidence of permanent adverse outcomes in the first 3 years was 10.7% and 2.4% thereafter. This difference was statistically significant (p = 0.015). There was no difference in the incidence of adverse outcomes when comparing surgery performed with and without participation of an advanced resident.

Conclusions

In this study the authors have demonstrated a learning curve in this series of patients. This study also suggests that involving residents in the repair of small unruptured aneurysms will not compromise patient care. In addition, patients can be informed that the team approach to their surgery is at least as good as having the experienced surgeon performing all aspects of the surgery.

Decrease of mortality of ruptured abdominal aortic aneurysm after centralization and in-hospital quality improvement of vascular service

Our aim was to determine whether organizational changes could improve the outcome after ruptured abdominal aortic aneurysm (RAAA). Regional centralization and quality improvement in the in-hospital chain of treatment of RAAA included strengthening of the emergency preparedness and better availability of postoperative intensive care. During the reorganization, all patients with RAAA were admitted to Helsinki University Central Hospital (HUCH) from Helsinki and Uusimaa district. RAAA patients in the hospital district of Helsinki and Uusimaa between 1996 and 2004 were identified. The study period was divided into three periods: I, control; II, change; and III, present. Of the total of 626 patients with RAAA, 352 (56%) were admitted to the HUCH, of whom 315 (90%) underwent surgery. During the study period, population-based mortality decreased from 77% to 56% (P < 0.001) and 90-day mortality, from 54% to 28% (P = 0.002). Operative 30-day mortality was 19% during the third period and lower than previously (P = 0.001). Our results seem to argue in favor of centralization of emergency vascular services with adequate manpower and operative expertise in the first line and with availability of closed-unit postoperative critical care to achieve better results as these measures were associated with a positive impact on survival.

Impact of hospital volume on recurrence and survival after surgery for gastric cancer

BACKGROUND

Some, but not all, studies using registry data have suggested a small but significant long-term survival advantage following a curative surgical resection of gastric cancer at hospitals where the volume of such surgeries is high. However, because such data may be significantly influenced by the impact of postoperative mortality, and may be imbalanced for factors important to survival, the true nature of this relationship remains uncertain.

METHODS

We conducted a nested volume-outcome study in a sample of 448 surgical survivors with stage IB through IV (M0) gastric and gastroesophageal junction adenocarcinoma, previously randomized to adjuvant chemoradiation after surgery or surgery alone, to measure the effect of hospital surgical volume, as assessed by Medicare claims data, on overall survival and gastric cancer recurrence.

RESULTS

In this selected sample of postoperative survivors, hospital surgical volume was not predictive of overall survival (P = 0.46) or disease-free survival (P = 0.43) at a median follow-up of 8.9 years. However, patients who underwent either a D1 or D2 dissection at a high- or moderate-volume center experienced an adjusted hazard ratio of 0.80 (95% CI, 0.53-1.20) for overall survival and 0.78 (95% CI, 0.53-1.14) for disease-free survival compared with those patients resected at a low-volume hospital; these results were not statistically significant. When a D0 resection was performed, hospital procedure volume showed no impact on survival.

CONCLUSIONS

Excluding the impact of perioperative mortality by utilizing prospectively recorded data from a large postoperative adjuvant trial, hospital procedure volume had no overall effect on long-term gastric cancer survival. The potential benefit of moderate- to high-volume centers for patients who underwent a D1 or D2 dissection requires confirmation in larger studies.

Bariatric surgery primer for the internist: keys to the surgical consultation

The increasing prevalence of morbid obesity in North America combined with the refinement of laparoscopic techniques for the performing these operations has contributed to the exponential growth of bariatric surgery over the last 10 years. There are many important considerations for the internist who is referring a patient for bariatric surgery.

A systematic review of the impact of volume of surgery and specialization on patient outcome

BACKGROUND AND METHODS

Volume of surgery and specialization may affect patient outcome. Articles examining the effects of one or more of three variables (hospital volume of surgery, surgeon volume and specialization) on outcome (measured by length of hospital stay, mortality and complication rate) were analysed. Reviews, opinion articles and observational studies were excluded. The methodological quality of each study was assessed, a correlation between the variables analysed and the outcome accepted if it was significant.

RESULTS

The search identified 55,391 articles published between 1957 and 2002; 1075 were relevant to the study, of which 163 (9,904,850 patients) fulfilled the entry criteria. These 163 examined 42 different surgical procedures, spanning 13 surgical specialities. None were randomized and 40 investigated more than one variable. Hospital volume was reported in 127 studies; high-volume hospitals had significantly better outcomes in 74.2 per cent of studies, but this effect was limited in prospective studies (40 per cent). Surgeon volume was reported in 58 studies; high-volume surgeons had significantly better outcomes in 74 per cent of studies. Specialization was reported in 22 studies; specialist surgeons had significantly better outcomes than general surgeons in 91 per cent of studies. The benefit of high surgeon volume and specialization varied in magnitude between specialities.

CONCLUSION

High surgeon volume and specialization are associated with improved patient outcome, while high hospital volume is of limited benefit.

Meta-analysis and systematic review of the relationship between volume and outcome in abdominal aortic aneurysm surgery

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 0·78 (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.

Provider volume and outcomes for abdominal aortic aneurysm repair, carotid endarterectomy, and lower extremity revascularization procedures

BACKGROUND

Intuitively, vascular procedures performed by high-volume vascular subspecialists working at high-volume institutions should be associated with improved patient outcome. Although a large number of studies assess the relationship between volume and outcome, a single contemporary compilation of such studies is lacking.

METHODS

A review of the English language literature was performed incorporating searches of the Medline, EMBASE, and Cochrane collaboration databases for abdominal aortic aneurysm repair (elective and emergent), carotid endarterectomy, and arterial lower limb procedures for any volume outcome relationship. Studies were included if they involved a patient cohort from 1980 onwards, were community or population based, and assessed health outcomes (mortality and morbidity) as a dependent variable and volume as an independent variable.

RESULTS

We identified 74 relevant studies, and 54 were included. All showed either an inverse relationship of variable magnitude between provider volume and mortality, or no volume-outcome effect. The reduction in the risk-adjusted mortality rate (RAMR) for high-volume providers was 3% to 11% for elective abdominal aortic aneurysm (AAA) repair, 2.5 to 5% for emergent AAA repair, 0.7% to 4.7% carotid endarterectomy, and 0.3% to 0.9% for lower limb arterial bypass procedures. Subspeciality training also conferred a considerable morbidity and mortality benefit for emergent AAA repair, carotid endarterectomy, and lower limb arterial procedures.

CONCLUSION

High-volume providers have significantly better outcomes for vascular procedures both in the elective and emergent setting. Subspeciality training also has a considerable impact. These data provide further evidence for the specialization of vascular services, whereby vascular procedures should generally be preformed by high-volume, speciality trained providers.