A model for national outcome audit in vascular surgery

Long-term risk prediction after major lower limb amputation: 1-year results of the PERCEIVE study

BACKGROUND

Decision-making when considering major lower limb amputation is complex and requires individualized outcome estimation. It is unknown how accurate healthcare professionals or relevant outcome prediction tools are at predicting outcomes at 1-year after major lower limb amputation.

METHODS

An international, multicentre prospective observational study evaluating healthcare professional accuracy in predicting outcomes 1 year after major lower limb amputation and evaluation of relevant outcome prediction tools identified in a systematic search of the literature was undertaken. Observed outcomes at 1 year were compared with: healthcare professionals' preoperative predictions of death (surgeons and anaesthetists), major lower limb amputation revision (surgeons) and ambulation (surgeons, specialist physiotherapists and vascular nurse practitioners); and probabilities calculated from relevant outcome prediction tools.

RESULTS

A total of 537 patients and 2244 healthcare professional predictions of outcomes were included. Surgeons and anaesthetists had acceptable discrimination (C-statistic = 0.715), calibration and overall performance (Brier score = 0.200) when predicting 1-year death, but performed worse when predicting major lower limb amputation revision and ambulation (C-statistics = 0.627 and 0.662 respectively). Healthcare professionals overestimated the death and major lower limb amputation revision risks. Consultants outperformed trainees, especially when predicting ambulation. Allied healthcare professionals marginally outperformed surgeons in predicting ambulation. Two outcome prediction tools (C-statistics = 0.755 and 0.717, Brier scores = 0.158 and 0.178) outperformed healthcare professionals' discrimination, calibration and overall performance in predicting death. Two outcome prediction tools for ambulation (C-statistics = 0.688 and 0.667) marginally outperformed healthcare professionals.

CONCLUSION

There is uncertainty in predicting 1-year outcomes following major lower limb amputation. Different professional groups performed comparably in this study. Two outcome prediction tools for death and two for ambulation outperformed healthcare professionals and may support shared decision-making.

More than 30 Years of POSSUM: Are Scoring Systems Still Relevant Today for Colorectal Surgery?

BACKGROUND

The Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) weights the patient's individual health status and the extent of the surgical procedure to estimate the probability of postoperative complications and death of general surgery patients. The variations Portsmouth-POSSUM (P-POSSUM) and colorectal POSSUM (CR-POSSUM) were developed for estimating mortality in patients with low perioperative risk and for patients with colorectal carcinoma, respectively. The aim of the present study was to evaluate the significance of POSSUM, P-POSSUM, and CR-POSSUM in two independent colorectal cancer cohorts undergoing surgery, with an emphasis on laparoscopic procedures.

METHODS

For each patient, an individual physiological score (PS) and operative severity score (OS) was attributed to calculate the predicted morbidity and mortality, respectively. Logistic regression analysis was used to evaluate the possible correlation between the subscores and the probability of postoperative complications and mortality.

RESULTS

The POSSUM equation significantly overpredicted postoperative morbidity, and all three scoring systems considerably overpredicted in-hospital mortality. However, the POSSUM score identified patients at risk of anastomotic leakage, sepsis, and the need for reoperation. Logistic regression analysis demonstrated a strong correlation between the subscores and the probability of postoperative complications and mortality, respectively.

CONCLUSION

Our results suggest that the three scoring systems are too imprecise for the estimation of perioperative complications and mortality of patients undergoing colorectal surgery in the present day. Since the subscores proved valid, a revision of the scoring systems could increase their reliability in the clinical setting.

Short-term risk prediction after major lower limb amputation: PERCEIVE study

BACKGROUND

The accuracy with which healthcare professionals (HCPs) and risk prediction tools predict outcomes after major lower limb amputation (MLLA) is uncertain. The aim of this study was to evaluate the accuracy of predicting short-term (30 days after MLLA) mortality, morbidity, and revisional surgery.

METHODS

The PERCEIVE (PrEdiction of Risk and Communication of outcomE following major lower limb amputation: a collaboratIVE) study was launched on 1 October 2020. It was an international multicentre study, including adults undergoing MLLA for complications of peripheral arterial disease and/or diabetes. Preoperative predictions of 30-day mortality, morbidity, and MLLA revision by surgeons and anaesthetists were recorded. Probabilities from relevant risk prediction tools were calculated. Evaluation of accuracy included measures of discrimination, calibration, and overall performance.

RESULTS

Some 537 patients were included. HCPs had acceptable discrimination in predicting mortality (931 predictions; C-statistic 0.758) and MLLA revision (565 predictions; C-statistic 0.756), but were poor at predicting morbidity (980 predictions; C-statistic 0.616). They overpredicted the risk of all outcomes. All except three risk prediction tools had worse discrimination than HCPs for predicting mortality (C-statistics 0.789, 0.774, and 0.773); two of these significantly overestimated the risk compared with HCPs. SORT version 2 (the only tool incorporating HCP predictions) demonstrated better calibration and overall performance (Brier score 0.082) than HCPs. Tools predicting morbidity and MLLA revision had poor discrimination (C-statistics 0.520 and 0.679).

CONCLUSION

Clinicians predicted mortality and MLLA revision well, but predicted morbidity poorly. They overestimated the risk of mortality, morbidity, and MLLA revision. Most short-term risk prediction tools had poorer discrimination or calibration than HCPs. The best method of predicting mortality was a statistical tool that incorporated HCP estimation.

Effects of hospital preference for endovascular repair on postoperative mortality after elective abdominal aortic aneurysm repair: analysis of the Dutch Surgical Aneurysm Audit

BACKGROUND

Increased use of endovascular aneurysm repair (EVAR) and reduced open surgical repair (OSR), has decreased postoperative mortality after elective repair of abdominal aortic aneurysms (AAAs). The choice between EVAR or OSR depends on aneurysm anatomy, and the experience and preference of the vascular surgeon, and therefore differs between hospitals. The aim of this study was to investigate the current mortality risk difference (RD) between EVAR and OSR, and the effect of hospital preference for EVAR on overall mortality.

METHODS

Primary elective infrarenal or juxtarenal aneurysm repairs registered in the Dutch Surgical Aneurysm Audit (2013-2017) were analysed. First, mortality in hospitals with a higher preference for EVAR (high-EVAR group) was compared with that in hospitals with a lower EVAR preference (low-EVAR group), divided by the median percentage of EVAR. Second, the mortality RD between EVAR and OSR was determined by unadjusted and adjusted linear regression and propensity-score (PS) analysis and then by instrumental-variable (IV) analysis, adjusting for unobserved confounders; percentage EVAR by hospital was used as the IV.

RESULTS

A total of 11 997 patients were included. The median hospital rate of EVAR was 76.6 per cent. The overall mortality RD between high- and low-EVAR hospitals was 0.1 (95 per cent -0.5 to 0.4) per cent. The OSR mortality rate was significantly higher among high-EVAR hospitals than low-EVAR hospitals: 7.3 versus 4.0 per cent (RD 3.3 (1.4 to 5.3) per cent). The EVAR mortality rate was also higher in high-EVAR hospitals: 0.9 versus 0.7 per cent (RD 0.2 (-0.0 to 0.6) per cent). The RD following unadjusted, adjusted, and PS analysis was 4.2 (3.7 to 4.8), 4.4 (3.8 to 5.0), and 4.7 (4.1 to 5.3) per cent in favour of EVAR over OSR. However, the RD after IV analysis was not significant: 1.3 (-0.9 to 3.6) per cent.

CONCLUSION

Even though EVAR has a lower mortality rate than OSR, the overall effect is offset by the high mortality rate after OSR in hospitals with a strong focus on EVAR.

Multidisciplinary quality improvement programme for older patients admitted to a vascular surgery ward

BACKGROUND

Older vascular surgical patients are at high risk of hospital-associated complications and prolonged stays.

AIMS

To implement a multidisciplinary co-management model for older vascular patients and evaluate impact on length of stay (LOS), delirium incidence, functional decline, medical complications and discharge destination.

METHODS

Prospective pre-post evaluation of a quality improvement intervention, enrolling pre-intervention (August 2012-January 2013) and post-intervention cohort (September 2013-March 2014). Participants were consenting patients aged 65 years and over admitted to the vascular surgical ward of a metropolitan teaching hospital for at least 3 days. Intervention was physician-led co-management plus a multidisciplinary improvement programme targeting delirium and functional decline. Primary outcomes were LOS, delirium and functional decline. Secondary outcomes were medical complications and discharge destination. Process measures included documented consultation patterns. Administrative data were also compared for all patients aged 65 and older for 12 months pre- and post-intervention.

RESULTS

We enrolled 112 participants pre-intervention and 123 participants post-intervention. LOS was reduced post-intervention (geometric mean 7.6 days vs 9.3 days; ratio of geometric means 0.82 (95% confidence interval CI0.68-1.00), P = 0.04). There was a trend to less delirium (18 (14.6%) vs 24 (21.4%), P = 0.17) and functional decline (18 (14.6%) vs 27 (24.3%), P = 0.06), with greatest reductions in the urgently admitted subgroup. Administrative data showed reduced median LOS (5.2 days vs 6 days, P = 0.03) and greater discharge home (72% vs 50%, P < 0.01).

CONCLUSIONS

Physician-led co-management plus a multidisciplinary improvement programme may reduce LOS and improve functional outcomes in older vascular surgical patients.

Systematic review of perioperative mortality risk prediction models for adults undergoing inpatient non-cardiac surgery

BACKGROUND

Risk prediction tools can be used in the perioperative setting to identify high-risk patients who may benefit from increased surveillance and monitoring in the postoperative period, to aid shared decision-making, and to benchmark risk-adjusted hospital performance. We evaluated perioperative risk prediction tools relevant to an Australian context.

METHODS

A systematic review of perioperative mortality risk prediction tools used for adults undergoing inpatient noncardiac surgery, published between 2011 and 2019 (following an earlier systematic review). We searched Medline via OVID using medical subject headings consistent with the three main areas of risk, surgery and mortality/morbidity. A similar search was conducted in Embase. Tools predicting morbidity but not mortality were excluded, as were those predicting a composite outcome that did not report predictive performance for mortality separately. Tools were also excluded if they were specifically designed for use in cardiac or other highly specialized surgery, emergency surgery, paediatrics or elderly patients.

RESULTS

Literature search identified 2568 studies for screening, of which 19 studies identified 21 risk prediction tools for inclusion.

CONCLUSION

Four tools are candidates for adapting in the Australian context, including the Surgical Mortality Probability Model (SMPM), Preoperative Score to Predict Postoperative Mortality (POSPOM), Surgical Outcome Risk Tool (SORT) and NZRISK. SORT has similar predictive performance to POSPOM, using only six variables instead of 17, contains all variables of the SMPM, and the original model developed in the UK has already been successfully adapted in New Zealand as NZRISK. Collecting the SORT and NZRISK variables in a national surgical outcomes study in Australia would present an opportunity to simultaneously investigate three of our four shortlisted models and to develop a locally valid perioperative mortality risk prediction model with high predictive performance.

Evaluation and validation of Physiological and Operative Severity Score for the enumeration of mortality and morbidity and Portsmouth-POSSUM scores in predicting morbidity and mortality in patients undergoing head and neck cancer surgeries

BACKGROUND

Identification of risk factors for perioperative complications helps in the prognostication. We wanted to determine whether Physiological and Operative Severity Score for the enumeration of mortality and morbidity (POSSUM) and Portsmouth-POSSUM (P-POSSUM) can be used in patients undergoing head and neck oncosurgery.

METHODS

We conducted a retrospective analysis of 1265 patients after they had major head and neck oncosurgeries. Demographic, surgical and outcome data was collected. We separately analyzed data for patients who had undergone cancer surgery for oral cavity, pharynx, and larynx. We calculated the POSSUM and P-POSSUM scores.

RESULTS

POSSUM scoring system had moderate discrimination (AUC = 0.61) and good calibration (P = .36) for the entire study cohort and in the subgroup. Since there were no deaths in the entire cohort, we were not able to check predictive ability of the scores, for mortality.

CONCLUSIONS

We found that POSSUM had moderate discrimination and good calibration for morbidity prediction in head and neck cancer surgeries, as well as for the selected subgroup.

Frailty In Patients Undergoing Vascular Surgery: A Narrative Review Of Current Evidence

Frailty is presumably associated with an elevated risk of postoperative mortality and adverse outcome in vascular surgery patients. The aim of our review was to identify possible methods for risk assessment and prehabilitation in order to improve recovery and postoperative outcome. The literature search was performed via PubMed, Embase, OvidSP, and the Cochrane Library. We collected papers published in peer-reviewed journals between 2001 and 2018. The selection criterion was the relationship between vascular surgery, frailty and postoperative outcome or mortality. A total number of 52 publications were included. Frailty increases the risk of non-home discharge independently of presence or absence of postoperative complications and it is related to a higher 30-day mortality and major morbidity. The modified Frailty Index showed significant association with elevated risk for post-interventional stroke, myocardial infarction, prolonged in-hospital stays and higher readmission rates. When adjusted for comorbidity and surgery type, frailty seems to impact medium-term survival (within 2 years). Preoperative physical exercising, avoidance of hypalbuminemia, psychological and cognitive training, maintenance of muscle strength, adequate perioperative nutrition, and management of smoking behaviours are leading to a reduced length of stay and a decreased incidence of readmission rate, thus improving the effectiveness of early rehabilitation. Pre-frailty is a dynamically changing state of the patient, capable of deteriorating or improving over time. With goal-directed preoperative interventions, the decline can be prevented.

Toward Optimizing Risk Adjustment in the Dutch Surgical Aneurysm Audit

BACKGROUND

To compare hospital outcomes of aortic aneurysm surgery, casemix correction for preoperative variables is essential. Most of these variables can be deduced from mortality risk prediction models. Our aim was to identify the optimal set of preoperative variables associated with mortality to establish a relevant and efficient casemix model.

METHODS

All patients prospectively registered between 2013 and 2016 in the Dutch Surgical Aneurysm Audit (DSAA) were included for the analysis. After multiple imputation for missing variables, predictors for mortality following univariable logistic regression were analyzed in a manual backward multivariable logistic regression model and compared with three standard mortality risk prediction models: Glasgow Aneurysm Score (GAS, mainly clinical parameters), Vascular Biochemical and Haematological Outcome Model (VBHOM, mainly laboratory parameters), and Dutch Aneurysm Score (DAS, both clinical and laboratory parameters). Discrimination and calibration were tested and considered good with a C-statistic > 0.8 and Hosmer-Lemeshow (H-L) P > 0.05.

RESULTS

There were 12,401 patients: 9,537 (76.9%) elective patients (EAAA), 913 (7.4%) acute symptomatic patients (SAAA), and 1,951 (15.7%) patients with acute rupture (RAAA). Overall postoperative mortality was 6.5%; 1.8% after EAAA surgery, 6.6% after SAAA, and 29.6% after RAAA surgery. The optimal set of independent variables associated with mortality was a mix of clinical and laboratory parameters: gender, age, pulmonary comorbidity, operative setting, creatinine, aneurysm size, hemoglobin, Glasgow coma scale, electrocardiography, and systolic blood pressure (C-statistic 0.871). External validation overall of VBHOM, DAS, and GAS revealed C-statistics of 0.836, 0.782, and 0.761, with an H-L of 0.028, 0.00, and 0.128, respectively.

CONCLUSIONS

The optimal set of variables for casemix correction in the DSAA comprises both clinical and laboratory parameters, which can be collected easily from electronic patient files and will lead to an efficient casemix model.

Validation of POSSUM, P-POSSUM and the surgical risk scale in major general surgical operations in Harare: A prospective observational study

BACKGROUND

Raw mortality and morbidity, though commonly studied in surgical audit can nonetheless be misleading because of differences in preoperative and intraoperative findings of patients. There are some common scoring systems specifically designed to cater for case mix but these have not been tried locally. This study sought to validate these scoring systems and hopefully adopt them for our teaching hospitals.

MATERIALS AND METHODS

A prospective observational cohort study was conducted at two central hospitals in Harare Two hundred and two patients undergoing a variety of major general surgical operations were recruited into the study. Results of physiological and intraoperative parameters collected from the patients' records were scored according to POSSUM, P-POSSUM and SRS scores. Predicted mortality and morbidity rates of all these subjects were then compared to the observed rates.

RESULTS

One hundred and eighty one patients participated (123 males, 58 females). Using the POSSUM morbidity score, the observed versus expected (O: E) ratio of 0.88 showed no difference (p = 0.970). Using POSSUM, P-POSSUM and SRS mortality scores, O: E ratios of 0.74, 1.06 and 1.0 respectively were obtained, the differences were not significant (p = 0.650, p = 0.987 and 0.730). All three scores were comparable on the Receiver Operating Characteristic curve. The Physiological score independently predicted mortality (p < 0.00001).

CONCLUSION

POSSUM, P-POSSUM and SRS scores are comparable and suitable for estimating outcomes after major surgery in Harare. A larger study inclusive of low risk patients is needed to generalise these findings across Zimbabwean patients.

The evaluation of risk prediction models in predicting outcomes after bariatric surgery: a prospective observational cohort pilot study

Background

As the prevalence of obesity is increasing, the number of patients requiring surgical intervention for obesity-related illness is also rising. The aim of this pilot study was to explore predictors of short-term morbidity and longer-term poor weight loss after bariatric surgery.

Methods

This was a single-centre prospective observational cohort pilot study in patients undergoing bariatric surgery. We assessed the accuracy (discrimination and calibration) of two previously validated risk prediction models (the Physiological and Operative Severity Score for the enumeration of Morbidity and Mortality, POSSUM score, and the Obesity Surgical Mortality Risk Score, OS-MS) for postoperative outcome (postoperative morbidity defined using the Post Operative Morbidity Survey). We then tested the relationship between postoperative morbidity and longer-term weight loss outcome adjusting for known patient risk factors.

Results

Complete data were collected on 197 patients who underwent surgery for obesity or obesity-related illnesses between March 2010 and September 2013. Results showed POSSUM and OS-MRS were less accurate at predicting Post Operative Morbidity Survey (POMS)-defined morbidity on day 3 than defining prolonged length of stay due to poor mobility and/or POMS-defined morbidity. Having fewer than 28 days alive and out of hospital within 30 days of surgery was predictive of poor weight loss at 1 year, independent of POSSUM-defined risk (odds ratio 2.6; 95% confidence interval 1.28-5.24).

Conclusions

POSSUM may be used to predict patients who will have prolonged postoperative LOS after bariatric surgery due to morbidity or poor mobility. However, independent of POSSUM score, having less than 28 days alive and out of hospital predicted poor weight loss outcome at 1 year. This adds to the literature that postoperative complications are independently associated with poor longer-term surgical outcomes.

Adjusted Hospital Outcomes of Abdominal Aortic Aneurysm Surgery Reported in the Dutch Surgical Aneurysm Audit

OBJECTIVE/BACKGROUND

The Dutch Surgical Aneurysm Audit (DSAA) is mandatory for all patients with primary abdominal aortic aneurysms (AAAs) in the Netherlands. The aims are to present the observed outcomes of AAA surgery against the predicted outcomes by means of V-POSSUM (Vascular-Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity). Adjusted mortality was calculated by the original and re-estimated V(physiology)-POSSUM for hospital comparisons.

METHODS

All patients operated on from January 2013 to December 2014 were included for analysis. Calibration and discrimination of V-POSSUM and V(p)-POSSUM was analysed. Mortality was benchmarked by means of the original V(p)-POSSUM formula and risk-adjusted by the re-estimated V(p)-POSSUM on the DSAA.

RESULTS

In total, 5898 patients were included for analysis: 4579 with elective AAA (EAAA) and 1319 with acute abdominal aortic aneurysm (AAAA), acute symptomatic (SAAA; n = 371) or ruptured (RAAA; n = 948). The percentage of endovascular aneurysm repair (EVAR) varied between hospitals but showed no relation to hospital volume (EAAA: p = .12; AAAA: p = .07). EAAA, SAAA, and RAAA mortality was, respectively, 1.9%, 7.5%, and 28.7%. Elective mortality was 0.9% after EVAR and 5.0% after open surgical repair versus 15.6% and 27.4%, respectively, after AAAA. V-POSSUM overestimated mortality in most EAAA risk groups (p < .01). The discriminative ability of V-POSSUM in EAAA was moderate (C-statistic: .719) and poor for V(p)-POSSUM (C-statistic: .665). V-POSSUM in AAAA repair overestimated in high risk groups, and underestimated in low risk groups (p < .01). The discriminative ability in AAAA of V-POSSUM was moderate (.713) and of V(p)-POSSUM poor (.688). Risk adjustment by the re-estimated V(p)-POSSUM did not have any effect on hospital variation in EAAA but did in AAAA.

CONCLUSION

Mortality in the DSAA was in line with the literature but is not discriminative for hospital comparisons in EAAA. Adjusting for V(p)-POSSUM, revealed no association between hospital volume and treatment or outcome. Risk adjustment for case mix by V(p)-POSSUM in patients with AAAA has been shown to be important.

Utility of Three Prognostic Risk Scores in Predicting Outcomes in Elderly Non-Malignant Patients after Percutaneous Gastrostomy

BACKGROUND/OBJECTIVES

Percutaneous endoscopic gastrostomy is a method of providing enteral feeding to patients who cannot take adequate oral nutrition. The aims of this study were to determine the performance of malnutrition and mortality scoring systems for predicting short and long-term mortality in elderly patients who had undergone gastrostomy procedure due to non-malignant conditions.

DESIGN

Retrospective cohort study.

SETTING

University hospital in Turkey.

PARTICIPANTS

155 individuals aged 65 and older principally hospitalized for non-malignant diseases and require percutaneous endoscopic gastrostomy.

MEASUREMENTS

"Geriatric Nutritional Risk Index", "Malnutrition Universal Screening Tool" (MUST) and "Portsmouth-Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity" (P-POSSUM) scores were calculated. The ability of these scores to predict mortality was determined.

RESULTS

The mean survival period was 9.59±6.0 months and mortality rate was 80.6%. The performance of "Geriatric Nutritional Risk Index" was superior to MUST and P-POSSUM in predicting long-term survival of gastrostomy patients; 94.1% of patients were alive with a cut-off value of 90 for "Geriatric Nutritional Risk Index" (sensitivity: 92% CI 85.9-95.6 and specificity: 90% CI 74.3-96.5). Survival analysis showed that patients (n=7) with a "Geriatric Nutritional Risk Index" score of > 98 before the gastrostomy had the longest survival time, while patients (n=102) with a "Geriatric Nutritional Risk Index" score of < 82 had the worst outcome.

CONCLUSIONS

A scoring system such as "Geriatric Nutritional Risk Index" should be considered as a risk scoring system for predicting early and late mortality at gastrostomy and also assist in making decisions such as timing of gastrostomy procedure.

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.

A ruptured abdominal aortic aneurysm that requires preoperative cardiopulmonary resuscitation is not necessarily lethal

OBJECTIVE

A ruptured abdominal aortic aneurysm (RAAA) is associated with a high mortality rate. If cardiopulmonary resuscitation (CPR) is required before surgical repair, mortality rates are said to approach 100%. The aim of this multicenter, retrospective study was to study outcome in RAAA patients who required CPR before a surgical (endovascular or open) repair (CPR group). RAAA patients who did not need CPR served as controls (non-CPR group).

METHODS

Over a 5-year time period, demographic and clinical characteristics and specifics of preoperative CPR if necessary were studied in all patients who were treated for a RAAA in three large, nonacademic hospitals.

RESULTS

A total of 199 consecutive RAAA patients were available for analysis; 176 patients were surgically treated. Thirteen of these 176 patients (7.4%) needed CPR, and 163 (92.6%) did not. A 38.5% (5 of 13) survival rate was observed in the CPR group. Thirty-day mortality was almost three times greater in the CPR group compared with the non-CPR group (61.5% vs 22.7%; P = .005). Both CPR patients who received endovascular aortic repair survived. In contrast, survival in 11 CPR patients who underwent open RAAA repair was 27% (3 of 11; P = .128). A trend for higher Hardman index was found in patients who received CPR compared with patients who did not receive CPR (P = .052). The 30-day mortality in patients with a 0, 1, 2, or 3 Hardman index was 16.1%, 31.0%, 37.9%, and 33.3%, respectively (P = .093).

CONCLUSIONS

An RAAA that requires preoperative CPR is not necessarily a lethal combination. Patient selection must be tailored before surgery is denied.

A new risk-scoring model for predicting 30-day mortality after repair of abdominal aortic aneurysms in the era of endovascular procedures

Purpose

To propose a new, multivariable risk-scoring model for predicting 30-day mortality in individuals underwent repair of abdominal aortic aneurysms (AAA).

Methods

Four hundred eighty-five consecutive patients who underwent AAA repair from January 2000 to December 2010 were included in the study. Univariate and multivariate analyses were performed to evaluate the risk factors, and a risk-scoring model was developed.

Results

Multivariate analysis identified three independent preoperative risk factors associated with mortality, and a risk-scoring model was created by assigning an equal value to each factor. The independent predictors were location of the AAA, rupture of AAA, and preoperative pulmonary dysfunction. The multivariable regression model demonstrated moderate discrimination (c statistic, 0.811) and calibration (Hosmer-Lemeshow test, P = 0.793). The observed mortality rate did not differ significantly from that predicted by our risk-scoring model.

Conclusion

Our risk-scoring model has excellent ability to predict 30-day mortality after AAA repair, and awaits validation in further studies.

An evaluation of POSSUM and P-POSSUM scoring in predicting post-operative mortality in a level 1 critical care setting

Background

POSSUM and P-POSSUM are used in the assessment of outcomes in surgical patients. Neither scoring systems’ accuracy has been established where a level 1 critical care facility (level 1 care ward) is available for perioperative care. We compared POSSUM and P-POSSUM predicted with observed mortality on a level 1 care ward.

Methods

A prospective, observational study was performed between May 2000 and June 2008. POSSUM and P-POSSUM scores were calculated for all postoperative patients who were admitted to the level 1 care ward. Data for post-operative mortality were obtained from hospital records for 2552 episodes of patient care. Observed vs expected mortality was compared using receiver operating characteristic (ROC) curves and the goodness of fit assessed using the Hosmer-Lemeshow equation.

Results

ROC curves show good discriminative ability between survivors and non-survivors for POSSUM and P-POSSUM. Physiological score had far higher discrimination than operative score. Both models showed poor calibration and poor goodness of fit (Hosmer-Lemeshow). Observed to expected (O:E) mortality ratio for POSSUM and P-POSSUM indicated significantly fewer than expected deaths in all deciles of risk.

Conclusions

Our data suggest a 30-60% reduction in O:E mortality. We suggest that the use of POSSUM models to predict mortality in patients admitted to level 1 care ward is inappropriate or that a recalibration of POSSUM is required to make it useful in a level 1 care ward setting.

[Value of modified POSSUM scoring system on predicting operation risk in elderly NSCLC patients]

BACKGROUND

For the assessment of elderly patients can tolerate lung cancer operation, there is no clear standard. To evaluate the clinical validity of POSSUM (Physiological and Operative Severity Score for the Umeration of Mortality and Morbidity) in elderly non-small cell lung cancer (NSCLC) surgery patients, we want to provide an important basis for operation treatment decisions.

METHODS

A total of 138 patients, with 88 males and 50 females, with elderly NSCLC surgery between December 2007 and December 2013, are included in PLA general hospital. Using the multivariate Logistic regression analysis, we evaluate the value of each factor on the actual postoperative complications mortality and morbidity. The scorings on standard POSSUM and modified POSSUM in the complication group are compared with the non-complication group using the group t test. Drawing receiver operating characteristic (ROC) curve in standard POSSUM group and modified POSSUM group, calculating the area under the curve (AUC), AUC in standard group is compared with modified group using t test. Judge if the modified POSSUM prediction is consistent with the actual mortality and morbidity.

RESULTS

Among 138 patients, there were 77 postoperative complications in 59 patients, 2 cases of death. According to the Logistic regression analysis, 17 of 18 factors in standard POSSUM, pulmonary function, different TNM stage are predictors for postoperative complications (P<0.05). Age is a predictor for postoperative death (P<0.05). In the standard POSSUM scoring, actual complication group compared with non-complication group, the difference is statistically significant (P<0.01). In the modified POSSUM scoring, complication group is compared with non-complication group, the difference is statistically significant (P<0.01). Compared with the standard POSSUM, the modified POSSUM has better predictive value on postoperative morbidity, and the comparison of AUC between the two groups is statistically significant. But the latter shows the overpredicted mortality (P<0.01).

CONCLUSIONS

The modified POSSUM has a good predictive value on postoperative complications in elderly NSCLC surgery patients, so it can provide the basis for decision-making operation treatment.

Predicting postoperative mortality after colorectal surgery: a novel clinical model

AIM

The aim of this study was to develop and externally validate a clinically, practical and discriminative prediction model designed to estimate in-hospital mortality of patients undergoing colorectal surgery.

METHOD

All consecutive patients who underwent elective or emergency colorectal surgery from 1990 to 2005, at the Zaandam Medical Centre, The Netherlands, were included in this study. Multivariate logistic regression analysis was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) linking the explanatory variables to the outcome variable in-hospital mortality, and a simplified Identification of Risk in Colorectal Surgery (IRCS) score was constructed. The model was validated in a population of patients who underwent colorectal surgery from 2005 to 2011 in Barcelona, Spain. Predictive performance was estimated by calculating the area under the receiver operating characteristic curve.

RESULTS

The strongest predictors of in-hospital mortality were emergency surgery (OR = 6.7, 95% CI 4.7-9.5), tumour stage (OR = 3.2, 95% CI 2.8-4.6), age (OR = 13.1, 95% CI 6.6-26.0), pulmonary failure (OR = 4.9, 95% CI 3.3-7.1) and cardiac failure (OR = 3.7, 95% CI 2.6-5.3). These parameters were included in the prediction model and simplified scoring system. The IRCS model predicted in-hospital mortality and demonstrated a predictive performance of 0.83 (95% CI 0.79-0.87) in the validation population. In this population the predictive performance of the CR-POSSUM score was 0.76 (95% CI 0.71-0.81).

CONCLUSIONS

The results of this study have shown that the IRCS score is a good predictor of in-hospital mortality after colorectal surgery despite the relatively low number of model parameters.

Evaluation of the POSSUM, P-POSSUM and E-PASS scores in the surgical treatment of hilar cholangiocarcinoma

Background

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) model, its Portsmouth (P-POSSUM) modification and the Estimation of physiologic ability and surgical stress (E-PASS) are three surgical risk scoring systems used extensively to predict postoperative morbidity and mortality in general surgery. The aim was to undertake the first study of the predictive value of these models in patients undergoing surgical treatment of hilar cholangiocarcinoma.

Methods

A retrospective analysis was performed on data collected prospectively over a 10-year interval from January 2003 to December 2012. The morbidity and mortality risks were calculated using the POSSUM, P-POSSUM and E-PASS equations.

Results

One hundred patients underwent surgical treatment of hilar cholangiocarcinoma. Complications were seen in 52 of 100 patients (52.0%). There were 10 postoperative in-hospital deaths (10.0%). Of 31 preoperative and intraoperative variables studied, operative type (P = 0.000), preoperative serum albumin (P = 0.003) and aspartate aminotransferase (P = 0.029) were found to be factors multivariate associated with postoperative complications. Intraoperative blood loss (P = 0.015), Bismuth-Corlette classification (P = 0.033) and preoperative hemoglobin (P = 0.041) were independent factors multivariate associated with in-hospital death. The POSSUM system predicted morbidity risk effectively with no significant lack of fit (P = 0.488) and an area under the ROC curve (AUC) of 0.843. POSSUM, P-POSSUM and E-PASS scores showed no significant lack of fit in calculating the mortality risk (P >0.05) and all yielded an AUC value exceeding 0.8. POSSUM had significantly more accuracy in predicting morbidity after major and major plus operations (O:E (observed/expected) ratio 0.98 and AUC 0.901) than after minor and moderate operations (O:E ratio 1.13 and AUC 0.759).

Conclusions

POSSUM, P-POSSUM and E-PASS scores effectively predict morbidity and mortality in surgical treatment of hilar cholangiocarcinoma. However, improvements are still needed in the future because none of these scoring systems yielded an AUC value exceeding 0.9 for operations with all different levels of severity. Only POSSUM had more accuracy in predicting postoperative morbidity after operations with higher severity.

Trial registration

This study was undertaken after obtaining approval from the ethics committee of School of Medicine, Shanghai Jiao Tong University with a trial registration number of http://09411960800.

Comparison of three contemporary risk scores for mortality following elective abdominal aortic aneurysm repair

Objective/background

A number of contemporary risk prediction models for mortality following elective abdominal aortic aneurysm (AAA) repair have been developed. Before a model is used either in clinical practice or to risk-adjust surgical outcome data it is important that its performance is assessed in external validation studies.

Methods

The British Aneurysm Repair (BAR) score, Medicare, and Vascular Governance North West (VGNW) models were validated using an independent prospectively collected sample of multicentre clinical audit data. Consecutive, data on 1,124 patients undergoing elective AAA repair at 17 hospitals in the north-west of England and Wales between April 2011 and March 2013 were analysed. The outcome measure was in-hospital mortality. Model calibration (observed to expected ratio with chi-square test, calibration plots, calibration intercept and slope) and discrimination (area under receiver operating characteristic curve [AUC]) were assessed in the overall cohort and procedural subgroups.

Results

The mean age of the population was 74.4 years (SD 7.7); 193 (17.2%) patients were women and the majority of patients (759, 67.5%) underwent endovascular aneurysm repair. All three models demonstrated good calibration in the overall cohort and procedural subgroups. Overall discrimination was excellent for the BAR score (AUC 0.83, 95% confidence interval [CI] 0.76–0.89), and acceptable for the Medicare and VGNW models, with AUCs of 0.78 (95% CI 0.70–0.86) and 0.75 (95% CI 0.65–0.84) respectively. Only the BAR score demonstrated good discrimination in procedural subgroups.

Conclusion

All three models demonstrated good calibration and discrimination for the prediction of in-hospital mortality following elective AAA repair and are potentially useful. The BAR score has a number of advantages, which include being developed on the most contemporaneous data, excellent overall discrimination, and good performance in procedural subgroups. Regular model validations and recalibration will be essential.

POSSUM and P-POSSUM as predictors of postoperative morbidity and mortality in patients undergoing hepato-biliary-pancreatic surgery: a meta-analysis

BACKGROUND

Physiologic and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) models are used extensively to predict postoperative morbidity and mortality in general surgery. The aim was to undertake the first meta-analysis of the predictive value of these models in patients undergoing hepato-biliary-pancreatic surgery.

METHODS

Eligible articles were identified by searches of electronic databases from 1991 to 2012. All data were specific to hepato-biliary-pancreatic surgery. Predictive value of morbidity and mortality were assessed by calculating weighted observed to expected (O/E) ratios. Subanalysis was also performed.

RESULTS

Sixteen studies were included in final review. The morbidity analysis included nine studies on POSSUM with a weighted O/E ratio of 0.78 [95 % confidence interval (CI) 0.68-0.88]. The mortality analysis included seven studies on POSSUM and nine studies on P-POSSUM (Portsmouth predictor equation for mortality). Weighted O/E ratios for mortality were 0.35 (95 % CI 0.17-0.54) for POSSUM and 0.95 (95 % CI 0.65-1.25) for P-POSSUM. POSSUM had more accuracy to predict morbidity after pancreatic surgery (O/E ratio 0.82; 95 % CI 0.72-0.92) than after hepatobiliary surgery (O/E ratio 0.66; 95 % CI 0.57-0.74), in large sample size studies (O/E ratio 0.90; 95 % CI 0.85-0.96) than in small sample size studies (O/E ratio 0.69; 95 % CI 0.59-0.79).

CONCLUSIONS

POSSUM overpredicted postoperative morbidity after hepato-biliary-pancreatic surgery. Predictive value of POSSUM to morbidity was affected by the type of surgery and the sample size of studies. Compared with POSSUM, P-POSSUM was more accurate for predicting postoperative mortality. Modifications to POSSUM and P-POSSUM are needed for audit in hepato-biliary-pancreatic surgery.

A systematic review of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity and its Portsmouth modification as predictors of post-operative morbidity and mortality in patients undergoing pancreatic surgery

BACKGROUND

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) model and its Portsmouth modification (P-POSSUM) are used extensively to predict postoperative mortality and morbidity in general surgery. The aim of this study was to undertake the first systematic review of the predictive value of these models in patients undergoing pancreatic surgery.

METHODS

Eligible articles were identified by searches of electronic databases for those published from 1991 to 2012. Two independent reviewers assessed each study against inclusion and exclusion criteria. All data were specific to pancreatic surgery. Predictive value of morbidity and mortality were assessed by calculating observed/expected ratios.

RESULTS

Nine studies were included in the final review. The morbidity analysis included 8 studies (1,734 patients) of POSSUM with a weighted observed/expected ratio of .85. The mortality analysis included 5 studies (936 patients) of POSSUM and 4 studies (716 patients) of P-POSSUM. Weighted observed/expected ratios for mortality were .35 for POSSUM and 1.39 for P-POSSUM.

CONCLUSIONS

POSSUM overpredicted postoperative morbidity in patients undergoing pancreatic surgery. Both POSSUM and P-POSSUM failed to offer significant predictive value for mortality in pancreatic surgery, and more data collection in large populations undergoing pancreatic surgery are needed.

Efficacy of VBHOM to Predict Outcome Following Major Lower Limb Amputation

Purpose: This study tests an existing Vascular Biochemistry and Haematology Outcome Model (VBHOM) on independent data and presents further refinements to the model. Methods: Data from 306 patients who underwent lower limb amputation over a 4-year period were collated. Urea, creatinine, sodium, potassium, hemoglobin, white cell count, albumin, age, gender, mode-of-admission, and short-term mortality events were extracted from the database. This study tests an existing model and trains a new model for predicting mortality using forward stepwise logistic regression. Results: The existing model suggests a significant lack of fit (c-index = 0.665, P = .04). For the exception of gender and mode-of-admission, all predictor variables had significant univariate associations with short-term mortality ( P < .05). The refined model included age, sodium, potassium, creatinine, and albumin and had good discriminatory power (c-index = 0.8, no evidence of lack of fit, P = .616). Conclusions: Our simplified model had good predictive ability and suggests redundancy in input variables used by the existing models.

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.

Laparoscopic versus open approach for aortobifemoral bypass for severe aorto-iliac occlusive disease--a multicentre randomised controlled trial

OBJECTIVES

To investigate differences between open and laparoscopic aortobifemoral bypass surgery for aorto-iliac occlusive disease on postoperative morbidity and mortality.

DESIGN

A multicentre randomised controlled trial.

METHODS

Between January 2007 and November 2009, 28 patients with severe aorto-iliac occlusive disease (TASC II C or D) were randomised between laparoscopic and open approach at one community hospital and one university hospital (TASC = Trans-Atlantic Inter-Society Consensus on the Management of Peripheral Arterial Disease).

RESULTS

The operation time was longer for the laparoscopic approach (mean 4 h 19 min (2 h 00 min to 6 h 20 min) vs. 3 h 30 min (1 h 42 min to 5 h 11 min); p = 0.101)). Nevertheless, postoperative recovery and in-hospital stay were significantly shorter after laparoscopic surgery. Also oral intake could be restarted earlier (mean 20 h 34 min (6 h 00 min to 26 h 55 min) vs. 43 h 43 min (19 h 40 min to 77 h 30 min); p = 0.00014)) as well as postoperative mobilisation (walking) (mean 46 h 15 min (16 h 07 min to 112 h 40 min) vs. mean 94 h 14 min (66 h 10 min to 127 h 23 min); p = 0.00016)). Length of hospitalisation was shorter (mean 5.5 days (2.5-15) vs. mean 13.0 days (7-45); p = 0.0095)). Visual pain scores and visual discomfort scores were both lower after laparoscopic surgery. Also return to normal daily activities was achieved earlier. There were no major complications in both groups.

CONCLUSION

Laparoscopic aortobifemoral bypass surgery for aorto-iliac occlusive disease is a safe procedure with a significant decrease in postoperative morbidity and in-hospital stay and earlier recovery.

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 &lt; 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.

Usefulness of POSSUM physiological score for the estimation of morbidity and mortality risk after elective abdominal aortic aneurysm repair in Japan

BACKGROUND

The Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM), which consists of a physiological score (PS) and an operative severity score, is useful in determining the risk profile for patients with abdominal aortic aneurysms in Western countries, but no information is available on the use of this method in Japan.

METHODS AND RESULTS

A retrospective cohort study involving 225 patients was performed, and the prognostic factors for morbidity and in-hospital mortality including POSSUM were investigated. The morbidity rate was 26%. On univariate analysis age, renal disease, hemoglobin, albumin, operation time, blood loss and PS were significantly different. On multivariate analysis PS was significantly different. Using receiver operating characteristic (ROC) analysis, PS had an area under the curve (AUC) of 0.712 and the best cut-off point was 18. The in-hospital mortality rate was 2.2%. On univariate analysis renal disease, albumin and PS were significantly different, and on multivariate analysis PS was significantly different. On ROC analysis PS had an AUC of 0.921 and the best cut-off point was 22.

CONCLUSIONS

PS was the only independent risk factor for morbidity and in-hospital mortality. Further studies may be required to develop a risk-scoring system.

POSSUM and its related models as predictors of postoperative mortality and morbidity in patients undergoing surgery for gastro-oesophageal cancer: a systematic review

BACKGROUND

Gastro-oesophageal surgery is associated with appreciable postoperative morbidity and mortality. POSSUM (Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity) and its related models P-POSSUM and O-POSSUM have been developed to predict such events in general surgery. The aim was to undertake the first systematic review of the use of these models in gastro-oesophageal surgery patients.

METHODS

An online database search was carried out from 1991 to December 2008.

RESULTS

Twenty-two published studies in gastro-oesophageal cancer surgery were identified. Twelve studies were found not to address the above aim, leaving ten relevant publications for analysis. Pooled data from these studies showed the weighted observed-to-expected ratio (O/E) for postoperative mortality using POSSUM (n = 1189), P-POSSUM (n = 2314), and O-POSSUM (n = 1755) was 0.37, 0.83, and 0.51, respectively. The weighted O/E for morbidity using POSSUM (n = 1038) was 0.86.

CONCLUSION

POSSUM and O-POSSUM most significantly overestimated postoperative mortality in gastro-oesophageal cancer patients. In contrast, P-POSSUM had the least overestimation and may be the most useful predictor of likely postoperative mortality in these patients.

Risk-adjusted scoring systems in colorectal surgery

Consequent to recent advances in surgical techniques and management, survival rate has increased substantially over the last 25 years, particularly in colorectal cancer patients. However, post-operative morbidity and mortality from colorectal cancer vary widely across the country. Therefore, standardised outcome measures are emphasised not only for professional accountability, but also for comparison between treatment units and regions. In a heterogeneous population, the use of crude mortality as an outcome measure for patients undergoing surgery is simply misleading. Meaningful comparisons, however, require accurate risk stratification of patients being analysed before conclusions can be reached regarding the outcomes recorded. Sub-specialised colorectal surgical units usually dedicated to more complex and high-risk operations. The need for accurate risk prediction is necessary in these units as both mortality and morbidity often are tools to justify the practice of high-risk surgery. The Acute Physiology And Chronic Health Evaluation (APACHE) is a system for classifying patients in the intensive care unit. However, APACHE score was considered too complex for general surgical use. The American Society of Anaesthesiologists (ASA) grade has been considered useful as an adjunct to informed consent and for monitoring surgical performance through time. ASA grade is simple but too subjective. The Physiological & Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) and its variant Portsmouth POSSUM (P-POSSUM) were devised to predict outcomes in surgical patients in general, taking into account of the variables in the case-mix. POSSUM has two parts, which include assessment of physiological parameters and operative scores. There are 12 physiological parameters and 6 operative measures. The physiological parameters are taken at the time of surgery. Each physiological parameter or operative variable is sub-divided into three or four levels with an exponentially increasing score. However, POSSUM and P-POSSUM over-predict mortality in patients who have had colorectal surgery. Discrepancies in these models have led to the introduction of a specialty-specific POSSUM: the ColoRectal POSSUM (CR-POSSUM). CR-POSSUM only uses six physiological parameters and four operative measures for prediction of mortality. It is much simplified to allow ease of use.

A systematic review of POSSUM and its related models as predictors of post-operative mortality and morbidity in patients undergoing surgery for colorectal cancer

INTRODUCTION

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) model and its Portsmouth (P-POSSUM) and colorectal (CR-POSSUM) modifications are used extensively to predict and audit post-operative mortality and morbidity. This aim of this systematic review was to assess the predictive value of the POSSUM models in colorectal cancer surgery.

METHODS

Major electronic databases, including Medline, Embase, Cochrane Library and Pubmed were searched for original studies published between 1991 and 2010. Two independent reviewers assessed each study against inclusion and exclusion criteria. All data was specific to colorectal cancer surgery. Predictive value was assessed by calculating observed to expected (O/E) ratios.

RESULTS

Nineteen studies were included in final review. The mortality analysis included ten studies (4,799 patients) on POSSUM, 17 studies (6,576 patients) on P-POSSUM and 14 studies (5,230 patients) on CR-POSSUM. Weighted O/E ratios for mortality were 0.31 (CI 0.31-0.32) for POSSUM, 0.90 (CI 0.88-0.92) for P-POSSUM and 0.64 (CI 0.63-0.65) for CR-POSSUM. The morbidity analysis included four studies (768 patients) on POSSUM with a weighted O/E ratio of 0.96 (CI 0.94-0.98).

CONCLUSIONS

P-POSSUM was the most accurate model for predicting post-operative mortality after colorectal cancer surgery. The original POSSUM model was accurate in predicting post-operative complications.

Identification and management of perioperative cardiovascular risk

Approximately 25 000 patients die each year in the UK following 1.3 million surgical procedures (Pearse et al, 2006). More than 80% of these perioperative deaths occur in patients who are at significantly high risk for surgery (12.5%) (Pearse et al, 2006). This population tends to be older, have multiple co-morbidities and have undergone major surgery. Notably, 50% were never admitted to a general intensive care unit postoperatively (Campling et al, 1993). Approximately 75% of patients who suffer perioperative death have cardiovascular disease, so it is important to try and identify these patients preoperatively (Mangano, 1990; National Confidential Enquiry into Perioperative Deaths, 2002).

Predicting post-operative mortality in patients undergoing colorectal surgery using P-POSSUM and CR-POSSUM scores: a prospective study

INTRODUCTION

POSSUM and its variants Portsmouth POSSUM (P-POSSUM) and Colorectal POSSUM (CR-POSSUM) equations were derived from a heterogeneous general surgical population, which have been used successfully to provide risk-adjusted operative mortality rates. CR-POSSUM utilises fewer parameters, allowing ease of use. The aim of this study was to predict the mortality outcome in colorectal surgery using these scoring systems compared to the observed mortality and to devise a new scoring system with improved accuracy.

METHODS

The study was conducted prospectively on all consecutive patients requiring elective and emergency colorectal surgery between April 2002 and May 2005. The outcome parameter was defined as 30-day mortality. The observed mortality was compared with predicted mortality by the scoring systems. Hosmer and Lemeshow test was used to assess statistical accuracy of POSSUM.

RESULTS

Eight hundred ninety-nine patients underwent colorectal surgery during the study period. There were 619 elective and 281 emergency patients. Observed 30-day mortality rate was 9%, compared with predicted mortality rate of 13.5% with POSSUM, 5% with P-POSSUM and 9.5% with CR-POSSUM.

CONCLUSION

POSSUM's mortality rate was overestimated, while P-POSSUM's mortality rate was underestimated. CR-POSSUM, the simplest system of all three, most accurately predicted mortality in our unit.

Validity of the orthopedic POSSUM scoring system for the assessment of postoperative mortality in patients with pressure ulcers

In the treatment of pressure ulcers, assessment of systemic problems is an important yet difficult step in selecting either conservative or surgical therapeutic intervention. The surgical auditing system called the Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) and its orthopedic version (O-POSSUM), which gives a predictive mortality rate for the first 30 postoperative days, may be useful for assessing systemic status, but have yet to be sufficiently validated for patients with pressure ulcers. To assess the validity of POSSUM and O-POSSUM, 71 procedures on 50 cases were retrospectively statistically analyzed using receiver operating characteristic curves and goodness-of-fitness testing with the Hosmer-Lemeshow chi(2) test for logistic regression modeling. POSSUM and O-POSSUM showed satisfactory discriminatory power in receiver operating curve analysis. The validity of the values obtained by POSSUM and O-POSSUM was also confirmed. O-POSSUM was superior to POSSUM in both analyses. O-POSSUM is useful in assessing the systemic status of patients with pressure ulcers. Some patients with pressure ulcers show extreme systemic conditions. Assessment of systemic status with O-POSSUM contributes to daily clinical practice and future studies of treatments for pressure ulcers.

Orthopaedic POSSUM scoring system: An assessment of the risk of debridement in patients with pressure sores

We hypothesised that the implementation of a validated method of audit, the Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM), would be useful in the evaluation of the risks of debridement in bedridden patients with pressure ulcers. With the orthopaedic version of POSSUM (O-POSSUM), physiological data and an operative profile are scored to predict mortality for 30 days postoperatively. Fourteen cases were analysed retrospectively. The difference in predicted mortality was compared with those who died and those who survived. The mean (SD) predicted mortality among those who died was 47 (16)%, and among those who lived was 18 (14)%. Those who died were classified as a relatively high risk group, and the values differed significantly (p=0.01). O-POSSUM may be helpful in audit.

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.

Prognostic scoring in ruptured abdominal aortic aneurysm: a prospective evaluation

BACKGROUND

Prospective validation of prognostic scoring systems for ruptured abdominal aortic aneurysm (AAA) is lacking. This study assesses the validity of three established risk scores and a new prognostic index.

METHOD

Patients admitted with ruptured AAA during a 26-month period (August 2002-December 2004) were recruited prospectively. The Glasgow Aneurysm Score (GAS), Hardman Index, Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) scores, and the Edinburgh Ruptured Aneurysm Score (ERAS) were recorded and related to outcome.

RESULTS

During the study period, 111 patients were admitted with ruptured AAA. Of these, 84 (76%) underwent attempted operative repair and were included in the study; 37 (44%) died after operation. The GAS, Hardman Index, and the ERAS were statistically related to mortality. However, analysis by receiver-operator characteristic curve revealed the ERAS to have an area under the curve (AUC) of 0.72 (95% confidence interval [CI], 0.61-0.83). The vascular (V)-POSSUM and ruptured AAA (RAAA)-POSSUM models had an AUC of 0.70 (95% CI, 0.59-0.82). The Hardman Index and GAS had an AUC of 0.69 (95% CI, 0.57-0.80) and 0.64 (95% CI, 0.52-0.76), respectively. Although the V-POSSUM equation predicted mortality effectively (P = .086), the RAAA-POSSUM derivative demonstrated a significant lack of fit (P = .009).

CONCLUSION

Prospective validation shows that the Hardman Index, GAS, and V-POSSUM and RAAA-POSSUM scores do not perform well as predictors for death after ruptured AAA. The ERAS accurately stratifies perioperative risk but requires further validation.