Comparison of risk-scoring methods in predicting the immediate outcome after elective open abdominal aortic aneurysm surgery

Validity of E-PASS Score for Evaluating Perioperative Minor Complications Associated with Carotid Endarterectomy

Carotid endarterectomy (CEA) is conducted to reduce the risk of cerebral infarction; therefore, a low complication rate is highly required. To predict long-term morbidity and mortality, various scoring systems have been considered; nonetheless, a model that can be utilized to estimate nonmajor temporary complications and minor complications is currently lacking. To evaluate the occurrence rate of perioperative complications in various surgical domains, the E-PASS (Estimation of Physiological Ability and Surgical Stress) score is employed. This study was carried out to investigate the utility of the E-PASS score as a predictive factor for the risk of minor complications in patients undergoing CEA. The retrospective analysis was performed for 104 consecutive series of CEA procedures carried out at Otaru Municipal Hospital. The correlation between E-PASS and the rate of minor complications was examined. Sensitivity and specificity were used to construct a receiver operating characteristic curve, and the area under the curve (AUC) was calculated for accuracy. Postoperative minor complications occurred in eight cases (7.7%), including six vagal nerve injuries and two pneumonia cases. Three categorical data-preoperative risk score, surgical stress scores, and comprehensive risk score (CRS) -showed a good relationship with the postoperative minor complication. Among them, CRS presented the highest sensitivity and specificity, as indicated by an AUC of 0.68. The CRS cutoff value was calculated as -0.068, with a 1.7% postoperative minor complication rate for those lower than -0.068 and 14.0% for those higher than -0.068. The E-PASS score was effective for evaluating and predicting postoperative minor complications in patients with CEA procedures.

Predictors of Operative Mortality of 928 Intact Aortoiliac Aneurysms

BACKGROUND

The aim of this study is to identify preoperative and intraoperative factors associated with in-hospital mortality of intact abdominal aortoiliac aneurysm repair.

METHODS

In this observational study, prospectively collected information included demographics, risk factors, comorbidities, aneurysm characteristics (including special aneurysm presentation, i.e., inflammatory, mycotic/infected, aortocaval fistula), investigations, and operative variables. Receiver operating characteristic) curve analysis of the Glasgow aneurysm score (GAS) and the Vascular Study Group of New England (VSGNE) score was performed in the subgroup of bland aneurysms undergoing isolated elective repair.

RESULTS

A total of 928 cases with intact aortoiliac aneurysms had an elective (n = 882) or urgent (n = 46) repair, associated with an in-hospital mortality of 1.7% and 8.7%, respectively (P = 0.01). Open repair (n = 514) was a predictor of higher mortality (3.3% vs. 0.5% for endovascular aneurysm repair [EVAR], n = 414, odds ratio [OR] 7.1, P = 0.003), and so was the pre-EVAR era (4.8% vs. 1.3% in the EVAR era, OR 4.0, P = 0.004). Other significant predictors included the presence of abdominal/back pain (7.5% vs. 1.3%, OR = 6.0, P = 0.001), preoperative angiography (7% vs. 1.6%, OR = 4.5, P = 0.01), special aneurysm presentation (10.9% vs. 1.5%, OR = 8.1, P < 0.001), concomitant major procedures (19% vs. 1.7%, OR = 14.0, P < 0.001), serious intraoperative complications (9.1% vs. 1.5%, OR = 6.6, P = 0.001), median number of transfused units of blood intraoperatively (2 and 0 for cases with and without mortality, respectively, P < 0.001), and procedure duration (270 and 150 min for cases with and without mortality, respectively, P < 0.001). Open repair (OR = 4.5, P = 0.05), special aneurysm presentation (OR = 6.58, P = 0.001), and concomitant major procedures (OR = 14.3, P < 0.001) were independent predictors of higher mortality. ROC curve analysis for the GAS (P = 0.87) and VSGNE score (P = 0.10) failed to demonstrate statistical significance in the subgroup of bland aneurysms undergoing isolated elective repair.

CONCLUSIONS

Our study has demonstrated independent risk factors for mortality, which should be considered when contemplating aortoiliac aneurysm repair. We failed to externally validate the GAS and VSGNE score.

Analysing the Society for Vascular Surgery and American Association for Vascular Surgery scoring systems for outcomes post-endovascular aortic repair

BACKGROUND AND AIMS

Assess the association between the Society for Vascular Surgery/American Association for Vascular Surgery (SVS/AVSS) (Rutherford et al., J Vasc Surg 26: 517-38, 1997; Chaikof et al., J Vasc Surg 35:1061-6, 2002) medical comorbidity scoring scheme (MCS), and the global scoring system (GS) and major morbidity and mortality after elective endovascular aneurysm repair. Primary end points were peri-operative morbidity and mortality. Secondary end points were intensive care unit admission, high dependency unit admission, total stay > 5 days and 2-year mortality.

METHODS

The project was approved by the Galway Clinical Research Ethics Committee. This project followed the Declaration of Helsinki. Binary logistic regression was performed to assess the association of the scores and their individual components with the primary and secondary outcomes. Results were reported as odds ratio (OR) per point increase in score with 95% confidence intervals (CI) and the Hosmer-Lemeshow (HL).

RESULTS

Between 2002 and 2015, 401 patients underwent elective EVARs. MCS was calculated for 396 patients while GS was calculated for 183 patients. The MCS (OR 1.906, CI 1.017-3.574, p = 0.044) was associated with perioperative morbidity. The MCS was associated with perioperative mortality (OR 8.875, CI 1.918-41.070, p = 0.005). The GS was associated with perioperative morbidity (OR 11.929, CI 1.151-123.584, p = .038) but not associated with perioperative mortality (OR 3.62, CI 0.006-2118.148, p = .692).

CONCLUSIONS

The MCS shows association with perioperative morbidity and mortality. GS shows association with perioperative morbidity but not perioperative mortality; however, this may be due to our study being underpowered. We believe that the analysis of higher numbers of patients could unmask trends in both of these scores and individual components of both scores changed.

Cytokines as biomarkers of inflammatory response after open versus endovascular repair of abdominal aortic aneurysms: a systematic review

The repair of an abdominal aortic aneurysm (AAA) is a high-risk surgical procedure related to hormonal and metabolic stress-related response with an ensuing activation of the inflammatory cascade. In contrast to open repair (OR), endovascular aortic aneurysm repair (EVAR) seems to decrease the postoperative stress by offering less extensive incisions, dissection, and tissue manipulation. However, these beneficial effects may be offset by the release of cytokines and arachidonic acid metabolites during intra-luminal manipulation of the thrombus using catheters in endovascular repair, resulting in systemic inflammatory response (SIR), which is clinically called post-implantation syndrome. In this systematic review we compared OR with EVAR in terms of the post-interventional inflammatory response resulting from alterations in the circulating cytokine levels. We sought to summarize all the latest evidence regarding post-implantation syndrome after EVAR. We searched Medline (PubMed), ClinicalTrials.gov and the Cochrane library for clinical studies reporting on the release of cytokines as part of the inflammatory response after both open/conventional and endovascular repair of the AAA. We identified 17 studies examining the cytokine levels after OR versus EVAR. OR seemed to be associated with a greater SIR than EVAR, as evidenced by the increased cytokine levels, particularly IL-6 and IL-8, whereas IL-1β, IL-10 and TNF-α showed conflicting results or no difference between the two groups. Polyester endografts appear to be positively correlated with the incidence of post-implantation syndrome after EVAR. Future large prospective studies are warranted to delineate the underlying mechanisms of the cytokine interaction in the post-surgical inflammatory response setting.

Current status of the treatment of infrarenal abdominal aortic aneurysms

Aortic aneurysms are the 13^th leading cause of death in the United States. While aneurysms can occur along the entire length of the aorta, the infrarenal location is the most common. Targeted ultrasound screening has been found to be an effective and economical means of preventing aortic aneurysm rupture. The indication for repair includes either symptomatic aneurysms or aneurysms with a diameter greater than 5.4 cm. Treatment options for the repair of infrarenal aortic aneurysms are open surgical repair (OSR) and endovascular aneurysm repair (EVAR). Currently, EVAR is the primary treatment method for the repair of infrarenal aortic aneurysms due to improved short-term morbidity and mortality outcomes. This article is intended to review the current status of the management of infrarenal abdominal aortic aneurysms (AAA).

Assessment of postoperative complications using E-PASS and APACHE II in patients undergoing oral and maxillofacial surgery

Background

The prediction of postoperative complications is important for oral and maxillofacial surgeons. We herein aimed to evaluate the efficacy of the Estimation of Physiologic Ability and Surgical Stress (E-PASS) and Acute Physiology, Age, and Chronic Health Evaluation (APACHE) II scoring systems to predict postoperative complications in patients undergoing oral and maxillofacial surgery.

Methods

Thirty patients (22 males, 8 females; mean age: 65.1 ± 12.9 years) who underwent major oral surgeries and stayed in the intensive care unit for postoperative management were enrolled in this study. Postoperative complications were discriminated according to the necessity of the therapeutic intervention by the Medical Department, i.e. according to the Clavien–Dingo classification. E-PASS and APACHE II scores as well as laboratory test values were compared between patients with/without postoperative complications.

Results

Postoperative complications were developed in seven patients. The comprehensive risk score (CRS: 1.13 ± 0.24) and APACHE II score (13.0 ± 2.58) were significantly higher in patients with postoperative complications than in those without ones (p < 0.01, p < 0.05, respectively). The CRS showed an appropriate discriminatory power for predicting postoperative complications (area under the curve: 0.814). Furthermore, a correlation was detected between APACHE II scores and postoperative data until C-reactive protein levels decreased to < 1.0 mg/L (r = 0.43, p < 0.05).

Conclusion

The E-PASS and APACHE II scoring systems were both shown to be useful to predict postoperative complications after oral and maxillofacial surgery.

Systematic review of mortality risk prediction models in the era of endovascular abdominal aortic aneurysm surgery

BACKGROUND

The introduction of endovascular aneurysm repair (EVAR) has reduced perioperative mortality after abdominal aortic aneurysm (AAA) surgery. The objective of this systematic review was to assess existing mortality risk prediction models, and identify which are most useful for patients undergoing AAA repair by either EVAR or open surgical repair.

METHODS

A systematic search of the literature was conducted for perioperative mortality risk prediction models for patients with AAA published since 2006. PRISMA guidelines were used; quality was appraised, and data were extracted and interpreted following the CHARMS guidelines.

RESULTS

Some 3903 studies were identified, of which 27 were selected. A total of 13 risk prediction models have been developed and directly validated. Most models were based on a UK or US population. The best performing models regarding both applicability and discrimination were the perioperative British Aneurysm Repair score (C-statistic 0·83) and the preoperative Vascular Biochemistry and Haematology Outcome Model (C-statistic 0·85), but both lacked substantial external validation.

CONCLUSION

Mortality risk prediction in AAA surgery has been modelled extensively, but many of these models are weak methodologically and have highly variable performance across different populations. New models are unlikely to be helpful; instead case-mix correction should be modelled and adapted to the population of interest using the relevant mortality predictors.

Estimation of V-POSSUM and E-PASS Scores in Prediction of Acute Kidney Injury in Patients after Elective Open Abdominal Aortic Aneurysm Surgery

BACKGROUND

V-POSSUM and E-PASS scoring systems are usually used to predict morbidity and early mortality in surgical patients. We conducted this study to assess the validity of the V-POSSUM and E-PASS scores in predicting risk of acute kidney injury (AKI) development in patients undergoing elective open abdominal aortic aneurysm (AAA) repair.

METHODS

We studied a consecutive series of 171 patients with AAA, qualified for elective open infrarenal repair. Patients underwent a thorough examination, and the physiological and surgical stress components of the V-POSSUM and E-PASS scores were calculated. The classification of patients in terms of postoperative AKI was performed in accordance with KDIGO criteria.

RESULTS

AKI was recognized in 62 patients. In these patients, we found significantly higher physiological and surgical stress components of V-POSSUM and E-PASS scores in relation to patients without AKI. ROC analysis showed that the E-PASS score with a cutoff point ≥0.796 and the V-POSSUM score (morbidity) with a cutoff point ≥77.2% with sensitivity of 75.8% and 74.2%, respectively, and with specificity of 83.5% for both, identified patients with postoperative AKI.

CONCLUSIONS

V-POSSUM and E-PASS scores have similar good properties in predicting postoperative AKI in patients undergoing elective open AAA repair.

Results of Open and Endovascular Abdominal Aortic Aneurysm Repair According to the E-PASS Score

Introduction:

Endovascular repair (EVAR) of abdominal aortic aneurysm has become the standard of care due to a lower 30-day mortality, a lower morbidity, shorter hospital stay and a quicker recovery. The role of open repair (OR) and to whom this type of operation should be offered is subject to discussion.

Objective:

To present a single center experience on the repair of abdominal aortic aneurysm, comparing the results of open and endovascular repairs.

Methods:

Retrospective cross-sectional observational study including 286 patients submitted to OR and 91 patients submitted to EVAR. The mean follow-up for the OR group was 66 months and for the EVAR group was 39 months.

Results:

The overall mortality was 11.89% for OR and 7.69% for EVAR (P=0.263), EVAR presented a death relative risk of 0.647. It was also found a lower intraoperative bleeding for EVAR (OR=1417.48±1180.42 mL versus EVAR=597.80±488.81 mL, P<0.0002) and a shorter operative time for endovascular repair (OR=4.40±1.08 hours versus EVAR=3.58±1.26 hours, P<0.003). The postoperative complications presented no statistical difference between groups (OR=29.03% versus EVAR=25.27%, P=0.35).

Conclusion:

EVAR presents a better short term outcome than OR in all classes of physiologic risk. In order to train future vascular surgeons on OR, only young and healthy patients, who carry a very low risk of adverse events, should be selected, aiming at the long term durability of the procedure.

The Impact of Aneurysm Morphology and Anatomic Characteristics on Long-Term Survival after Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Hostile anatomic characteristics in patients undergoing endovascular abdominal aortic aneurysm repair (EVAR) and the placement of endografts not in concordance with the specific device anatomic guidelines (or instructions for use [IFU]) have shown decreased technical success of the procedure. But these factors have never been evaluated in regard to patient postoperative survival. We sought to assess the association between survival and (1) aneurysm anatomy and characteristics and (2) implantation in compliance with manufacturer's anatomic IFU guidelines in patients undergoing endovascular aortic aneurysm repair.

METHODS

The cohort included 273 consecutive patients who underwent EVAR at Baylor Heart and Vascular Hospital between January 1, 2002 and December 31, 2009 and had their preoperative computed tomography (CT) scan digitally retrievable. The CT scans and operative notes were then reviewed, and the anatomic severity grading (ASG) score, maximum aneurysm diameter, thrombus width, patency of aortic side branch vessels, and implantation in compliance with IFU guidelines were assessed. The unadjusted association between survival (assessed until November 1, 2011) and these variables was assessed with the Kaplan-Meier method. Moreover, propensity-adjusted (for a comprehensive array of clinical and nonclinical risk factors) proportional hazard models were developed to assess the adjusted associations.

RESULTS

Seven (2.56%) patients died within 30 days from EVAR, and 88 (30.04%) patients died during the study follow-up. Patient mean survival was 6.3 years. The unadjusted analysis showed a statistically significant association between survival and thrombus width (P = 0.007), ASG score (P = 0.004), and implantation in compliance with IFU guidelines (P = 0.007). However, the adjusted analysis revealed that none of the anatomic and compliance factors were significantly associated with long-term survival (ASG, P = 0.149; diameter, P = 0.836; thrombus, P = 0.639; patency, P = 0.219; and implantation compliance, P = 0.219).

CONCLUSIONS

Unfavorable aneurysm morphologic characteristics and endograft implantation not in compliance with IFU guidelines did not adversely affect patient survival after EVAR in this group of patients. This implies that unfavorable anatomy, even that which would necessitate implantation of the EVAR device outside of the IFU guidelines, should not necessarily contraindicate EVAR.

Calculating when elective abdominal aortic aneurysm repair improves survival for individual patients: development of the Aneurysm Repair Decision Aid and economic evaluation

BACKGROUND

Abdominal aortic aneurysm (AAA) repair aims to prevent premature death from AAA rupture. Elective repair is currently recommended when AAA diameter reaches 5.5 cm (men) and 5.0 cm (women). Applying population-based indications may not be appropriate for individual patient decisions, as the optimal indication is likely to differ between patients based on age and comorbidities.

OBJECTIVE

To develop an Aneurysm Repair Decision Aid (ARDA) to indicate when elective AAA repair optimises survival for individual patients and to assess the cost-effectiveness and associated uncertainty of elective repair at the aneurysm diameter recommended by the ARDA compared with current practice.

DATA SOURCES

The UK Vascular Governance North West and National Vascular Database provided individual patient data to develop predictive models for perioperative mortality and survival. Data from published literature were used to model AAA growth and risk of rupture. The cost-effectiveness analysis used data from published literature and from local and national databases.

METHODS

A combination of systematic review methods and clinical registries were used to provide data to populate models and inform the structure of the ARDA. Discrete event simulation (DES) was used to model the patient journey from diagnosis to death and synthesised data were used to estimate patient outcomes and costs for elective repair at alternative aneurysm diameters. Eight patient clinical scenarios (vignettes) were used as exemplars. The DES structure was validated by clinical and statistical experts. The economic evaluation estimated costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) from the NHS, social care provider and patient perspective over a lifetime horizon. Cost-effectiveness acceptability analyses and probabilistic sensitivity analyses explored uncertainty in the data and the value for money of ARDA-based decisions. The ARDA outcome measures include perioperative mortality risk, annual risk of rupture, 1-, 5- and 10-year survival, postoperative long-term survival, median life expectancy and predicted time to current threshold for aneurysm repair. The primary economic measure was the ICER using the QALY as the measure of health benefit.

RESULTS

The analysis demonstrated it is feasible to build and run a complex clinical decision aid using DES. The model results support current guidelines for most vignettes but suggest that earlier repair may be effective in younger, fitter patients and ongoing surveillance may be effective in elderly patients with comorbidities. The model adds information to support decisions for patients with aneurysms outside current indications. The economic evaluation suggests that using the ARDA compared with current guidelines could be cost-effective but there is a high level of uncertainty.

LIMITATIONS

Lack of high-quality long-term data to populate all sections of the model meant that there is high uncertainty about the long-term clinical and economic consequences of repair. Modelling assumptions were necessary and the developed survival models require external validation.

CONCLUSIONS

The ARDA provides detailed information on the potential consequences of AAA repair or a decision not to repair that may be helpful to vascular surgeons and their patients in reaching informed decisions. Further research is required to reduce uncertainty about key data, including reintervention following AAA repair, and assess the acceptability and feasibility of the ARDA for use in routine clinical practice.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Predictive value of E-PASS and POSSUM systems for postoperative risk assessment of spinal surgery

Object

The Estimation of Physiological Ability and Surgical Stress (E-PASS) and Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) systems are surgical risk scoring systems that take into account both the patient's preoperative condition and intraoperative variables. While they predict postoperative morbidity and mortality rates for several types of surgery, spinal surgeries are currently not included. The authors assessed the usefulness of E-PASS and POSSUM algorithms and compared the predictive ability of both systems in patients with spinal disorders considered for surgery.

Methods

The E-PASS system includes a preoperative risk score, a surgical stress score, and a comprehensive risk score that is determined by both the preoperative risk score and surgical stress score. The POSSUM system is composed of a physiological score and an operative severity score; its total score is based on both the physiological score and operative severity score. The authors calculated the E-PASS and POSSUM scores for 601 consecutive patients who had undergone spinal surgery and investigated the relationship between the individual scores of both systems and the incidence of postoperative complications. They also assessed the correctness of the predicted morbidity rate of both systems.

Results

Postoperative complications developed in 64 patients (10.6%); there were no in-hospital deaths. All EPASS scores (p ≤ 0.001) and the operative severity score and total score of the POSSUM (p < 0.03) were significantly higher in patients with postoperative complications than in those without postoperative complications. The morbidity rates correlated linearly and significantly with all E-PASS scores (p ≤ 0.001); their coefficients (preoperative risk score, ρ = 0.179; surgical stress score, ρ = 0.131; and comprehensive risk score, ρ = 0.198) were higher than those for the POSSUM scores (physiological score, ρ = 0.059; operative severity score, ρ = 0.111; and total score, ρ = 0.091). The area under the receiver operating characteristic curve for the predicted morbidity rate was 0.668 for the E-PASS and 0.588 for the POSSUM system.

Conclusions

As E-PASS predicted morbidity more correctly than POSSUM, it is useful for estimating the postoperative risk of patients considered for spinal surgery.

Specialized vascular floors after open aortic surgery: cost containment while preserving quality outcomes

BACKGROUND

Postoperative care of open abdominal aortic surgery (OAAS) traditionally involves the intensive care unit (ICU). We hypothesized that in patients without an indication for postoperative ICU admission, admission to a specialized vascular floor unit (hemodynamic monitoring, 2:1 nursing) offers cost savings to both payer and institution without compromising care.

METHODS

The electronic medical record was used to collect perioperative data for patients who underwent OAAS between July 2007 and July 2011. The university's cost accounting system provided information on revenue, total margin, and professional billing. Patients with ICU indications (spinal drain, Swan-Ganz monitoring, vasopressors, intubation, or blood product resuscitation) were excluded. Comparative cost and outcome analysis was performed on vascular ward and ICU admissions using the Fisher's exact test for dichotomous categorical variables and the Student's t-test for continuous variables. Long-term survival comparison was calculated using Kaplan-Meier survival estimates.

RESULTS

One hundred thirty of 215 patients were included for analysis (85 excluded, 51 floor, 79 ICU). Perioperative data amongst the floor and ICU cohorts were similar. Day of operation professional billing fees were comparable (ICU $13,365 vs. floor $12,626; P = 0.18); however, postoperative professional fees were significantly higher in the ICU cohort (ICU $3,258 vs. floor $2,101; P = 0.001) primarily because of intensivist billing. The hospital generated an average of 8.7% more revenue from the ICU cohort (ICU $37,770 vs. floor $34,756; P = 0.023). This was offset by greater expenses in the ICU cohort (ICU $30,756 vs. floor $25,144; P = 0.02), yielding a hospital profit margin of 107.5% favoring floor admission (ICU $2,858 vs. floor $5,931; P = 0.19). Duration of stay was similar (ICU 8.0 days vs. floor 7.8 days; P = 0.86). Kaplan-Meier survival analysis was not significantly different between cohorts (ICU 10.1%, median follow-up, 1,070 days vs. floor 0%, median follow-up, 405 days; P = 0.13).

CONCLUSIONS

Postoperative admission to the ICU is not always necessary after OAAS. Specialized vascular floors offer a financial savings to both payer and institution, which allows for simultaneous cost containment while preserving quality outcomes.

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

Background

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

Methods

Data on elective AAA repairs from the NVD between January 2008 and December 2010 were analysed. The models assessed were: Glasgow Aneurysm Score (GAS), Vascular Biochemical and Haematological Outcome Model (VBHOM), physiological component of the Vascular Physiological and Operative Severity Score for enUmeration of Mortality (V-POSSUM), Medicare and Vascular Governance North West (VGNW). Overall model discrimination and calibration in equally sized risk-group quintiles were assessed.

Results

The study cohort included 10 891 patients undergoing elective AAA repair (median age 74 years, 87·3 per cent men). The in-hospital mortality rates following endovascular and open repair were 1·3 and 4·7 per cent respectively (2·9 per cent overall). The Medicare and VGNW models both showed good discrimination (area under receiver operating characteristic (ROC) curve 0·71), whereas the GAS, VBHOM and V-POSSUM models showed poor discrimination (area under ROC curve 0·60, 0·61 and 0·62 respectively). The VGNW model was the only one to predict the overall mortality rate in the cohort (3·3 per cent predicted versus 2·9 per cent observed; P = 0·066). The VGNW model demonstrated good calibration, predicting risk accurately in four risk-group quintiles. The Medicare, V-POSSUM and VBHOM models accurately predicted risk in three, two and no risk-group quintiles respectively.

Conclusion

The Medicare and VGNW models contain similar risk factors and showed good discrimination when applied to the NVD. Both models would be suitable for risk prediction after elective AAA repair in the UK.

The Glasgow Aneurysm Score does not predict mortality after open abdominal aortic aneurysm in the era of endovascular aneurysm repair

OBJECTIVE

Endovascular aneurysm repair (EVAR) has reduced early adverse outcomes from abdominal aortic aneurysm (AAA) repair. Preferential use of EVAR may have altered the profile of patients who undergo open repair. The validity of scoring systems such as the Glasgow Aneurysm Score (GAS), devised when open surgery was the only treatment, required reappraisal.

METHODS

Patients were identified from a database of patients undergoing elective infrarenal aneurysm repair at seven United Kingdom centers, and the GAS was calculated for each patient. Discrimination and calibration were calculated to determine the performance of the model in this setting using the C statistic, tertile analysis, and the χ(2) test. Univariate analysis was performed to determine if a new iteration of the GAS could be produced.

RESULTS

We identified 330 patients who met the inclusion criteria. There were 18 deaths ≤30 days of surgery (5.4%). The average (standard deviation) GAS was 78.6 (8.8) for the survivors and 81.9 (10.4) for nonsurvivors (P = .122). The C statistic was 0.625 (95% confidence interval, 0.481-0.769; P = .75) suggesting a discriminatory ability not much better than chance alone. Despite this, calibration of the model was good. There was no significant difference in the comorbidities of either group, so no recalibration of the GAS could be performed.

CONCLUSION

The GAS did not discriminate between survivors and nonsurvivors after open AAA repair in this cohort. In the era of EVAR, it is possible that the GAS does not predict the outcome of open AAA repair. An alternative explanation is that patients with risk factors for poor outcomes from EVAR, such as adverse AAA morphology, are being selected out for open repair.

Prediction of anastomotic leak and its prognosis in digestive surgery

BACKGROUND

Anastomotic leak (AL) is a dangerous postoperative complication in gastrointestinal surgery. The present study focuses on whether our prediction scoring system, "Estimation of Physiologic Ability and Surgical Stress" (E-PASS), could predict occurrence of AL and its prognosis in various kinds of gastrointestinal surgical procedures.

METHODS

We prospectively investigated parameters of E-PASS, absence or presence of AL, and in-hospital mortality in 6,005 patients who underwent elective digestive surgery with alimentary tract reconstruction in 45 acute care hospitals in Japan between 1 April 2002 and 31 March 2007.

RESULTS

Incidences of AL were 19.6% for esophagectomy via right thoracotomy and laparotomy, 11.7% for pancreaticoduodenectomy, 7.4% for low anterior resection, 4.0% for total gastrectomy, 1.8% for open distal gastrectomy, 1.3% for open colectomy, for an overall incidence of 4.1%. The incidence in each procedure significantly correlated with median value of surgical stress score of the E-PASS (R = 0.78, n = 11, p = 0.0048). The incidences of AL increased when Total Risk Points (TRP) of the E-PASS increased; 1.1% at the TRP range of <500, 2.8% at 500 to <1,000, 4.8% at 1,000 to <1,500, and 13.6% at ≥ 1,500 (p < 0.0001). In patients who suffered from AL, an in-hospital mortality rate at TRP < 1,000 was significantly lower than that at TRP of ≥ 1,000 (1.1 vs. 15.9%; p = 0.00019).

CONCLUSIONS

The E-PASS, requiring only nine variables, may be useful in predicting AL and its prognosis.

Estimation of physiologic ability and surgical stress score does not predict immediate outcome after pancreatic surgery

OBJECTIVE

The Estimation of Physiologic Ability and Surgical Stress score was designed to predict postoperative morbidity and mortality in general surgery. Our study aims to evaluate its use and accuracy in estimating postoperative outcome after elective pancreatic surgery.

METHODS

Between 2002 and 2007, approximately 304 patients requiring pancreatic resection at our institution were recorded prospectively and evaluated retrospectively. The patients' preoperative risk score, surgical stress score (SSS), and comprehensive risk score (CRS) were calculated and compared with the severity of postoperative morbidity, where mortality was regarded as the most severe postoperative complication.

RESULTS

Observed and predicted mortality rates were 2.9% and 2.0%, respectively. Mean CRS was higher in patients who died than in patients that survived, but this difference was not statistically significant (P = 0.20). Preoperative risk score, SSS, and CRS did not differ between patients with and without complications (preoperative risk score: P = 0.32; SSS: P = 0.22; CRS: P = 0.13). Estimation of Physiologic Ability and Surgical Stress particularly underpredicted morbidity in patients with a CRS between 0.0 and less than 0.5.

CONCLUSIONS

The Estimation of Physiologic Ability and Surgical Stress scoring system is an ineffective predictor of complications after pancreatic resection. Further refinements to the score calculation are warranted to provide accurate prediction of immediate surgical outcome after pancreatic surgery.

Evaluation of estimation of physiologic ability and surgical stress to predict in-hospital mortality in cardiac surgery

PURPOSE

Prediction of postoperative risk in cardiac surgery is important for cardiac surgeons and anesthesiologists. We generated a prediction rule for elective digestive surgery, designated as Estimation of Physiologic Ability and Surgical Stress (E-PASS). This study was undertaken to evaluate the accuracy of E-PASS in predicting postoperative risk in cardiac surgery.

METHODS

We retrospectively collected data from patients who underwent elective cardiac surgery at a low-volume center (N = 291) and at a high-volume center (N = 784). Data were collected based on the variables required by E-PASS, the European system for cardiac operative risk evaluation (EuroSCORE), and the Ontario Province Risk Score (OPRS). Calibration and discrimination were assessed by the Hosmer-Lemeshow test and the area under the receiver operating characteristic curve (AUC), respectively. The ratio of observed-to-estimated in-hospital mortality rates (OE ratio) was defined as a measure of quality.

RESULTS

In-hospital mortality rates were 7.6% at the low-volume center and 1.3% at the high-volume center, accounting for an overall mortality rate of 3.0%. AUC values to detect in-hospital mortality were 0.88 for E-PASS, 0.77 for EuroSCORE, and 0.71 for OPRS. Hosmer-Lemeshow analysis showed a good calibration in all models (P = 0.81 for E-PASS, P = 0.49 for EuroSCORE, and P = 0.94 for OPRS). OE ratios for the low-volume center were 0.83 for E-PASS, 0.70 for EuroSCORE, and 0.83 for OPRS, whereas those for the high-volume center were 0.26 for E-PASS, 0.14 for EuroSCORE, and 0.27 for OPRS.

CONCLUSIONS

E-PASS may accurately predict postoperative risk in cardiac surgery. Because the variables are different between cardiac-specific models and E-PASS, patients' risks can be double-checked by cardiac surgeons using cardiac-specific models and by anesthesiologists using E-PASS.

Physiologic component of the estimation of physiologic ability and surgical stress scoring system as a predictor of immediate outcome after elective open abdominal aortic aneurysm repair

BACKGROUND

Previous studies have shown a good predictive power of the risk scoring method, Estimation of Physiologic Ability and Surgical Stress, in predicting mortality after open elective aortic aneurysm repair. The aim of the present study was to evaluate the physiologic component of this method to assess mortality risk in a different geographic population from previously published reports.

METHODS

Operative, morbidity and mortality data were collected retrospectively from charts of patients submitted to elective open repair of an abdominal aortic aneurysm over an 8-year period. There were 214 patients, the median age was 70 (range: 48-91) years; 179 (83.6%) patients were men. The Preoperative Physiologic Risk Score (PRS), Surgical Stress Score, and Comprehensive Risk Score (CRS) values were categorized and compared with morbidity and mortality rates.

RESULTS

There were 27 deaths (12.6%), and 81 (37.9%) patients experienced a postoperative complication that required medical intervention. There was a significant statistical difference for the values of PRS and CRS for patients who survived (0.53/0.63, respectively) and for those who died (0.88/1.02, respectively), p < 0.0001 for both values. There is a strong correlation between PRS and CRS values and development of complications (p < 0.0001). Surgical Stress Score did not correlate as strongly to development of complications (p = 0.0028). For PRS, the area under the receiver-operator characteristic curve was 0.844 (95% confidence interval: 0.747-0.941) for mortality and 0.725 (95% confidence interval: 0.650-0.799) for morbidity. For CRS, the area under the curve was 0.812 (95% confidence interval: 0.734-0.891) for mortality and 0.719 (95% confidence interval: 0.645-0.792) for morbidity. There was also a significant positive correlation between length of hospital stay and PRS and CRS scores (p < 0.0001). In this study, it was found that renal impairment has a significant positive correlation with mortality (p = 0.0008), with an odds ratio of 4.3. In a multivariate regression analysis, renal impairment failed to increase the accuracy of the model when associated with the other parameters considered in PRS.

CONCLUSION

This study corroborates with the previous findings that the Estimation of Physiologic Ability and Surgical Stress model seems to be a promising method of predicting death and postoperative complications in patients undergoing open abdominal aortic aneurysm repair.

Logistic risk model for mortality following elective abdominal aortic aneurysm repair

BACKGROUND

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

METHODS

Data collected prospectively on 2765 consecutive patients undergoing elective open and endovascular AAA repair from September 1999 to October 2009 in the North West of England were split randomly into development (1936 patients) and validation (829) data sets. Logistic regression analysis was undertaken to identify risk factors for 30-day mortality.

RESULTS

Ninety-eight deaths (5·1 per cent) were recorded in the development data set. Variables associated with 30-day mortality included: increasing age (P = 0·005), female sex (P = 0·002), diabetes (P = 0·029), raised serum creatinine level (P = 0·006), respiratory disease (P = 0·031), antiplatelet medication (P < 0·001) and open surgery (P = 0·002). The area under the receiver operating characteristic (ROC) curve for predicted probability of 30-day mortality in the development and validation data sets was 0·73 and 0·70 respectively. Observed versus expected 30-day mortality was 3·2 versus 2·0 per cent (P = 0·272) in low-risk, 6·1 versus 5·1 per cent (P = 0·671) in medium-risk and 11·1 versus 10·7 per cent (P = 0·879) in high-risk patients.

CONCLUSION

This multivariable model for predicting 30-day mortality following elective AAA repair can be used clinically to calculate patient-specific risk and is useful for case-mix adjustment. The model predicted well across all risk groups in the validation data set.

A multicenter prospective study of surgical audit systems

OBJECTIVE

This study was undertaken to evaluate a modified form of Estimation of Physiologic Ability and Surgical Stress (E-PASS) for surgical audit comparing with other existing models.

BACKGROUND

Although several scoring systems have been devised for surgical audit, no nation-wide survey has been performed yet.

METHODS

We modified our previous E-PASS surgical audit system by computing the weights of 41 procedures, using data from 4925 patients who underwent elective digestive surgery, designated it as mE-PASS. Subsequently, a prospective cohort study was conducted in 43 national hospitals in Japan from April 1, 2005, to April 8, 2007. Variables for the E-PASS and American Society of Anesthesiologists (ASA) status-based model were collected for 5272 surgically treated patients. Of the 5272 patients, we also collected data for the Portsmouth modification of Physiologic and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) in 3128 patients. The area under the receiver operative characteristic curve (AUC) was used to evaluate discrimination performance to detect in-hospital mortality. The ratio of observed to estimated in-hospital mortality rates (OE ratio) was defined as a measure of quality.

RESULTS

The numbers of variables required were 10 for E-PASS, 7 for mE-PASS, 20 for P-POSSUM, and 4 for the ASA status-based model. The AUC (95% confidence interval) values were 0.86 (0.79-0.93) for E-PASS, 0.86 (0.79-0.92) for mE-PASS, 0.81 (0.75-0.88) for P-POSSUM, and 0.73 (0.63-0.83) for the ASA status-based model. The OE ratios for mE-PASS among large-volume hospitals significantly correlated with those for E-PASS (R = 0.93, N = 9, P = 0.00026), P-POSSUM (R = 0.96, N = 6, P = 0.0021), and ASA status-based model (R = 0.83, N = 9, P = 0.0051).

CONCLUSION

Because of its features of easy use, accuracy, and generalizability, mE-PASS is a candidate for a nation-wide survey.

Why routine intensive care unit admission after elective open infrarenal Abdominal Aortic Aneurysm repair is no longer an evidence based practice

BACKGROUND

Elective open infrarenal Abdominal Aortic Aneurysm (AAA) repair is major surgery performed on high-risk patients. Routine ICU admission postoperatively is the current accepted standard of care. Few of these patients actually require a level of care that cannot be provided just as effectively in a surgical high dependency unit (HDU). Our aim was to determine, 'can high risk patients that will require ICU admission postoperatively be reliably identified preoperatively?'.

METHODS

A retrospective analysis of all elective open infrarenal AAA repairs in our institution over a 3-year period was performed. The Estimation of Physiological Ability and Surgical Stress (E-PASS) model was used as our risk stratification tool for predicting post-operative morbidity. Renal function was also considered as a predictor of outcome, independent of the E-PASS.

RESULTS

80% (n = 16) were admitted to ICU. Only 30% (n = 6) of the total study population necessitated intensive care. There were 9 complications in 7 patients in our study. The E-PASS comprehensive risk score (CRS)/Surgical stress score (SSS) were found to be significantly associated with the presence of a complication (p = 0.009)/(p = 0.032) respectively. Serum creatinine (p = 0.013) was similarly significantly associated with the presence of a complication.

CONCLUSIONS

The E-PASS model possessing increasing external validity is an effective risk stratification tool in safely deciding the appropriate level of post-operative care for elective infrarenal AAA repairs.

Is an estimation of physiologic ability and surgical stress able to predict operative morbidity after pancreaticoduodenectomy?

BACKGROUND

Mortality rates after pancreaticoduodenectomy (PD) are below 4% in high volume centers, although morbidity rates still remain high. Therefore, it is important to clarify a predictor associated with operative morbidity after PD. The estimation of physiologic ability and surgical stress (E-PASS) score has been developed for comparative audit in general surgical patients.

OBJECTIVE

To evaluate whether E-PASS scoring system could predict the occurrence of complications after PD.

METHODS

We performed retrospective analysis of 69 patients (42.0% pancreatic cancer, 31.9% bile duct cancer, and others) who underwent PD using the E-PASS as a predictor of morbidity. Correlations between the incidence rates of postoperative complications and the preoperative risk score (PRS), surgical stress score (SSS) and comprehensive risk score (CRS) of the E-PASS scoring system were evaluated.

RESULTS

Of the 69 patients 30 (43.5%) experienced a total of 54 postoperative complications. All E-PASS scores, especially PRS and CRS were significantly higher in the patients with postoperative complications than in the patients without complication. The complication rate gradually increased as the PRS, SSS and CRS score increased. Under receiver operating characteristic analysis, if a cut-off point of CRS was 0.75, sensitivity and specificity for the prediction of operative morbidity after PD was 80.0 and 79.5%, respectively. Neoadjuvant chemotherapy and intraoperative radiation therapy (IORT) did not influenced on operative morbidity after PD.

CONCLUSION

E-PASS scoring system is useful to evaluate for morbidity after PD. Neoadjuvant chemotherapy and IORT could be adapted without significant extra risk for surgical complication.

Predicting risk in elective abdominal aortic aneurysm repair: a systematic review of current evidence

OBJECTIVE

To examine and compare existing pre-operative risk prediction methods for elective abdominal aortic aneurysm (AAA) repair.

DESIGN

Systematic review.

METHODS

Medline, EMBASE and the Cochrane library were searched for articles that related to risk prediction models used for elective AAA repair.

RESULTS

680 abstracts were reviewed and after exclusions 28 articles encompassing 10 risk models were identified. The most frequently studied of these were the Glasgow Aneurysm Score (GAS), the Physiological and Operative Severity Score for enUmeration of Mortality (POSSUM) predictor equation and the Vascular Biochemistry and Haematology Outcome Model (VBHOM). All models had strengths and weaknesses and some had unique features which were identified and discussed.

CONCLUSION

The GAS appeared to be the most useful and consistently validated score at present for open repair. Other systems were either not validated fully or were not consistently accurate. Some had significant drawbacks which appeared to severely limit their clinical application. Recent work has shown that no scores consistently predicted the risk associated with endovascular aneurysm repair (EVAR). Pre-operative risk stratification is a vital component of modern surgical practice, and we propose the need for a comprehensive new risk scoring method for AAA repair incorporating anatomical and physiological data.

Objective risk-scoring systems for repair of abdominal aortic aneurysms: applicability in endovascular repair?

OBJECTIVES

Recent studies propose the use of objective risk-scoring systems as a clinical tool for selecting patients for open or endovascular abdominal aortic aneurysm repair (EVR). The aim of this study was to evaluate four established risk-scoring systems for accuracy of prediction of early mortality and morbidity following EVR.

PATIENTS AND METHODS

266 consecutive patients undergoing elective EVR at St. George's Vascular Institute between July 2001 and January 2007 were studied using a prospective database. The Glasgow Aneurysm Score (GAS), the Vascular Physiology and Operative Severity Score for the enUmeration of Mortality and Morbidity (V-POSSUM), the modified Customised Probability Index (m-CPI) and the Customised Probability Index (CPI) were applied for prediction of 30-day mortality and morbidity. Accuracy of prediction was compared using receiver operating characteristics (ROC) curve analyses.

RESULTS

30-day mortality and morbidity rates were 4% (11/266) and 8% (22/266) respectively. For prediction of mortality, GAS, V-POSSUM, m-CPI and CPI ROC curve analyses showed areas under the curves (AUCs) of 0.68 (95% confidence interval (CI), 0.48-0.87; p=0.046), 0.66 (95% CI, 0.51-0.81; p=0.067), 0.63 (95% CI, 0.45-0.81; p=0.148) and 0.65 (95% CI, 0.49-0.80; p=0.101) respectively. Corresponding AUCs for prediction of morbidity were 0.64 (95% CI, 0.51-0.76; p=0.511), 0.62 (95% CI, 0.51-0.74; p=0.505), 0.54 (95% CI, 0.41-0.67; p=0.416) and 0.55 (95% CI, 0.42-0.68; p=0.451).

CONCLUSIONS

GAS, V-POSSUM, m-CPI and CPI were poor predictors of early mortality and morbidity following EVR in this series. Caution should be applied to the use of these scoring systems for pre-operative risk stratification and treatment selection for endovascular repair of abdominal aneurysms.