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

Novel Risk Score Calculator for Perioperative Mortality after EVAR with Incorporation of Anatomical Factors

BACKGROUND

Hostile proximal aortic neck anatomy has been associated with an increased risk of perioperative mortality after endovascular aneurysm repair (EVAR). However, all available mortality risk prediction models after EVAR lack neck anatomic associations. The aim of this study is to develop a preoperative prediction model for perioperative mortality after EVAR incorporating important anatomic factors.

METHODS

Data were obtained from the Vascular Quality Initiative database on all patients who underwent elective EVAR between January 2015 and December 2018. A stepwise multivariable logistic regression analysis was implemented to identify independent predictors and develop a risk calculator for perioperative mortality after EVAR. Internal validation was done using bootstrap of 1,000 reps.

RESULTS

A total of 25,133 patients were included, of whom 1.1% (N = 271) died within 30 days or before discharge. Significant preoperative predictors of perioperative mortality were age (odds ratio [OR], 1.053; 95% confidence interval [CI], 1.050-1.056; P < 0.001), female sex (OR, 1.46; 95% CI, 1.38-1.54; P < 0.001), chronic kidney disease (OR, 1.65; 95% CI, 1.57-1.73; P < 0.001), chronic obstructive pulmonary disease (OR, 1.86; 95% CI, 1.77-1.94; P < 0.001), congestive heart failure (OR, 2.02; 95% CI, 1.91-2.13, P < 0.001), aneurysm diameter ≥ 6.5 cm (OR, 2.35; 95% CI, 2.24-2.47, P < 0.001), proximal neck length < 10 mm (OR, 1.96; 95% CI, 1.81-2.12; P < 0.001), proximal neck diameter ≥ 30 mm (OR, 1.41; 95% CI, 1.32-1.5; P < 0.001), infrarenal neck angulation ≥ 60° (OR, 1.27; 95% CI, 1.18-1.26; P < 0.001), and suprarenal neck angulation ≥ 60° (OR, 1.26; 95% CI, 1.16-1.37; P < 0.001). Significant protective factors included aspirin use (OR, 0.89; 95% CI, 0.85-0.93; P < 0.001) and statin intake (OR, 0.77; 95% CI, 0.73-0.81; P < 0.001). These predictors were incorporated to build an interactive risk calculator of perioperative mortality after EVAR (C-statistic = 0.749).

CONCLUSIONS

This study provides a prediction model for mortality following EVAR that incorporates aortic neck features. The risk calculator can be used to weigh risk/benefit ratio when counseling patients preoperatively. Prospective use of this risk calculator may show its benefit in long-term prediction of adverse outcomes.

Impact of frailty on risk of long-term functional decline following vascular surgery

OBJECTIVE

Frailty is a clinical syndrome associated with slow recovery after vascular surgery. However, the degree and length of functional impairment frail patients experience after surgery is unclear. The objective of this study was to prospectively measure changes in functional status among frail and non-frail patients undergoing a spectrum of different vascular surgery procedures.

METHODS

Patients consented to undergo elective minor and major vascular surgery procedures at an academic medical center between May 2018 and March 2019 were prospectively identified. Prior to surgery, all patients underwent provider assessment of frailty using the validated Clinical Frailty Scale (CFS), as well as baseline assessment of functional status using the Katz Activities of Daily Living (ADL) index and the Lawton Instrumental Activities of Daily Living (iADL) index. These same instruments were used to evaluate each patient's functional status at 2-weeks, 1-month, 1-year, and 2-year time points following surgery. Changes in iADL and ADL scores among frail (CFS ≥5) and non-frail patients were compared using paired Wilcoxon signed-rank tests and logistic regression models.

RESULTS

A total of 126 patients were assessed before and after minor (55%) and major (45%) vascular procedures, of which 43 patients (34%) were determined to be frail prior to surgery. Frail patients were older and more likely than non-frail patients to have medical comorbidities including chronic kidney disease, chronic obstructive pulmonary disease, or diabetes (all P < .05). When compared with the non-frail cohort, frail patients had significantly lower ADL and iADL scores before surgery and experienced a greater decline in ability to independently complete ADL and iADL activities after surgery that was sustained at 2 years (P < .05 and P < .001, respectively). After risk-adjustment, frailty was associated with an increased likelihood of decline in ADLs (odds ratio, 5.4; 95% confidence interval, 1.9-15.4; P < .05) and iADLs (odds ratio, 6.3; 95% confidence interval, 2.6-15.1; P < .001) at 2 years following surgery.

CONCLUSIONS

Frail patients experience a significant decline in ability to perform ADL and iADLs that persists 2 years following vascular surgery. These data highlight the degree of functional decline occurring immediately following surgery, as well as risk for long-term, sustained impairment that should be shared with frail patients before undergoing a procedure.

Illness wellness scale: novel grading system for performance status of patients under surgical care

BACKGROUND

Grading the illness using clinical parameters is essential for the daily progress of inpatients. Existing systems do not incorporate these parameters holistically. The study was designed to internally validate the illness wellness scale, based upon clinical assessment of the patients requiring surgical care, for their risk stratification and uniformity of communication between health care providers.

METHODS

Prospective observational study conducted at a tertiary care hospital. An expert panel devised the scale, and it was modified after feedback from 100 health care providers. A total of 210 patients (150 for internal validation and 60 for inter-observer variability) who required care under the department of surgical disciplines were enrolled. This included patients presenting to surgery OPD, admitted to COVID/non-COVID surgical wards and ICUs, aged ≥16 years.

RESULTS

The response rate of the final illness wellness scale was 95% with 86% positive feedback and a mean of 1.7 on the Likert scale for ease of use (one being very easy and five being difficult). It showed excellent consistency and minimal inter-observer variability with the intra-class correlation coefficient (ICC) above 0.9. In the internal validation cohort (n = 150), univariate and multivariable analysis of factors affecting mortality revealed that categorical risk stratification, age ≥ 60 years, presence or absence of co-morbidities especially hypertension and chronic kidney disease significantly affect mortality.

CONCLUSIONS

The Illness wellness scale is an effective tool for uniformly communicating between health care professionals and is also a strong predictor of risk stratification and mortality in patients requiring surgical care.

Perioperative risk prediction using the POSSUM and V-POSSUM models in symptomatic carotid stenosis

Summary: Background: This study aimed to evaluate risk factors for adverse outcomes and perioperative stroke and death in patients with symptomatic carotid stenosis undergoing open endarterectomy (CEA). The second objective was to assess the predictive value of the POSSUM and V-POSSUM models for predicting morbidity and mortality from CEA in symptomatic carotid stenosis. Patients and methods: A retrospective observational study of all patients admitted to a single center who underwent CEA for symptomatic carotid stenosis was performed. 320 patients from 1999 to 2013 were included. Postoperative complications, 30-day survival, and stroke rates were recorded. The observed outcomes were compared to the POSSUM and V-POSSUM expected mortality (observed to expected ratio (O:E)). Results: The mean age was 68.1±10.0 years. 215 patients were male (67%). Risk factors for surgical complications were: age, with a higher risk in both groups of less than 60 years and more than 75 years of age (p=0.04), a higher ASA score (p=0.04), and hyperlipidemia (p=0.017). Risk factors for the combined endpoint stroke or death were a higher ASA category (p<0.001), stroke as indication for CEA (p 0.022), and a high degree of stenosis (p=0.019). For POSSUM predicted mortality, there was a good O:E ratio in the two lowest risk groups, but a 2-fold overprediction of death or stroke in the two high-risk strata. The area under the curve (AUC) was 0.58 (95% CI: 0.43–0.73). The V-POSSUM showed a better fit in the high-risk groups, but an underprediction of mortality in the low-risk strata. Conclusions: Age and comorbid conditions are risk factors for adverse outcomes after CEA. The V-POSSUM model is better than POSSUM to predict postoperative death and stroke after CEA in patients with symptomatic carotid stenosis and a high preoperative physiological score. In patients with low physiological scores, both POSSUM and V-POSSUM show a limited predictive value.

Effect of Preoperative Chronic Opioid Use on Mortality and Morbidity in Vascular Surgical Patients

Introduction

Opioid derivates are an essential part of everyday clinical pain management practice. They have excellent analgesic, sedative, and sympatholytic effects and are widely used in various conditions. Beyond advantageous aspects, there are numerous problems with the chronic use of these agents. Dependency and life-threatening complications are the biggest problems with both illegal and prescribed opioid derivates. In our current study, effects of chronic opioid use were observed on mortality and life quality in the case of vascular surgery.

Methods

This prospective, observational study was conducted between 2014 and 2017. After obtaining informed consent, all participants were asked to fill a questionnaire containing different psychological tests. Perioperative data, chronic medical therapy, and anthropometric data were also collected. Opioid user and non-user patients’ psychological results were compared with non-parametrical tests. The effect of chronic opioid administration was investigated with logistic regression method with bootstrapping.

Results

Finally, the data of 164 patients were analyzed. 64.0% of participants were male, the mean age was 67.05 years, and the standard deviation was 9.48 years. The median follow-up time was 1312 days [interquartile range (IQR): 930-1582 days]. During the follow-up time, 42 patients died (25.6%). In the examined patient cohort, the frequency of opioid derivate use was 3.7% (only six patients). In the non-survived group, opioid use was significantly higher (1.6% vs. 9.5%, p=0.019). Significant differences were found in the aspect of cognitive performance measured by Mini-Mental State Examination (MMSE), opioid users have had lower points [25.5 (IQR: 24.5-26.0) vs. 28.0 (IQR: 27.0-29.0) p=0.008]. Opioid users have showed higher score on Beck Depression Inventory (BDI) [15.5 (IQR: 10.0-18.0) vs. 6.0 (IQR: 3.0-11.0), p=0.030). In a multivariate Cox regression model built up from registered preoperative medical treatment, opioids were found as a risk factor for all-cause mortality [adjusted hazard ratio (AHR): 4.31, 95% CI: 1.77-10.55, p=0.001].

Conclusion

Our current findings suggest that chronic, preoperative use of opioids could associate with increased mortality. Furthermore, both decrease in cognitive performance and increased depression symptoms were found in the opioid user cohorts which emphasize the importance of further risk stratification of these patients.

Long-Term Impact of Vascular Surgery Stress on Frail Older Patients

BACKGROUND

Frailty is a syndrome where the ability to cope with acute physiological stress is compromised, although it is unclear what impact this stress has on long-term outcomes. Vascular-Physiological and Operative Severity Score for enumeration of Mortality and Morbidity is a validated method for calculating levels of stress associated with vascular procedures. We designed this study to evaluate the long-term impact of different levels of surgical stress among frail older patients undergoing vascular surgery procedures.

METHODS

We identified all independently living patients who underwent prospective frailty assessment followed by an elective vascular surgery procedure captured in the Vascular Quality Initiative registry (endovascular abdominal aortic aneurysm [AAA] repair, thoracic endovascular aortic repair, suprainguinal and infrainguinal bypass, peripheral vascular intervention, carotid endarterectomy, and open AAA) at an academic institution between January 2016 and July 2018. Patient- and procedure-level data were obtained from our institutional data warehouse and Vascular Quality Initiative database, and used to calculate Vascular-Physiological and Operative Severity Score for enumeration of Mortality and Morbidity scores. The association between frailty and composite outcome of any major complications (surgical site infection; graft thrombectomy; major amputation; adverse cardiac, pulmonary, or neurologic event; acute renal insufficiency; and/or reoperation related to the index procedure), nonhome living status, or death within 1 year after low-, medium-, and high-stress vascular procedures was evaluated using bivariate and logistic regression models.

RESULTS

A total of 163 patients were identified (70% male, mean age 67.8 years) who underwent open AAA repair (6%), endovascular AAA repair (21%), thoracic endovascular aortic repair (7%), suprainguinal bypass (5%), infrainguinal bypass (18%), carotid endarterectomy (18%), or peripheral vascular interventions (25%), which included 44 (27%) patients diagnosed with frailty before surgery. Overall, frail patients had significantly higher rates of the 1-year composite outcome (48% frail versus 27% nonfrail; P = 0.012) when compared with nonfrail patients, with a significant dose-dependent effect as the level of stress increased. In comparison, increasing levels of surgical stress had a negligible effect on long-term outcomes among nonfrail patients. The interaction between frailty and high surgical stress was found in adjusted regression models to be a significant predictor of adverse outcomes within 1 year after vascular surgery (odds ratio, 3.3; 95% confidence interval, 1.3-8.6; P < 0.01).

CONCLUSIONS

Frail patients who undergo high-stress vascular procedures have a significantly higher rate of complications leading to loss of functional independence and mortality within the year after their surgery. These data suggest that estimates of surgical stress should be incorporated into clinical decision making for frail older patients before and after surgery.

External Validation Of The Surgical Mortality Probability Model (S-MPM) In Patients Undergoing Non-Cardiac Surgery

Background

Preoperative risk assessment is a key issue in the process of patient preparation for surgery and the control of quality improvement in health care and certification programs. Hence, there is a need for a prognostic tool, whose usefulness can be assessed only after validation in the center other than the home one. The aim of the study was to validate the Surgical Mortality Probability Model (S-MPM) for detecting deaths and complications in patients undergoing non-cardiac surgery and to assess its suitability for various surgical disciplines.

Methods

This retrospective study involved 38,555 adult patients undergoing non-cardiac surgery in a single center in 2012–2015. The observation period concerned in-hospital mortality.

Results

In-hospital mortality for the total population was 0.89%. Mortality in the S-MPM I class amounted to 0.26%, S-MPM II 2.51%, and in the S-MPM III class 22.14%. This result was in line with those obtained by the authors. The discriminatory power for in-hospital mortality was good (area under curve (AUC) = 0.852, 95% CI: 0.834–0.869, p = 0.0000). The scale was the most accurate in general surgery (AUC = 0.89, 95% CI: 0.858–0.922) and trauma (AUC = 0.89; 95% CI: 0.87–0.915). In the logistic regression analysis, the scale showed a perfect fit/goodness of fit in the cross-validation method (v-fold cross-validation): Hosmer–Lemeshow (HL) = 7.945; p = 0.159. This result was confirmed by the traditional derivation and validation data set method (1:3; 9712 vs 22.748 cases): HL test = 3.073 (p = 0.546) in the teaching derivation data set and 10.77 (p = 0.029) in the test sample (validation data set).

Conclusion

The S-MPM scale by Glance et al has proven to be a useful tool to assess the risk of in-hospital death and can be taken into account when considering treatment indications, patient information, planning post-operative care, and quality control.

Decision uncertainty and value of further research: a case-study in fenestrated endovascular aneurysm repair for complex abdominal aortic aneurysms

Background

Fenestrated endovascular aneurysm repair (fEVAR) is a new approach for complex abdominal aortic aneurysms, limited to a few specialist centers, with limited evidence base. We developed a cost-effectiveness decision model of fEVAR compared to open surgical repair (OSR) to investigate the likely direction of costs and benefits and inform further research projects on this technology.

Methods

A systematic review with meta-analysis and a four-state Markov model were used to estimate the cost-effectiveness of fEVAR versus OSR. We used a recent coverage with evidence development framework to characterize the main sources of uncertainty and inform decisions about the type of further research that would be most worthwhile and feasible.

Results

Seven observational comparative studies were identified, of which four presented odds ratios adjusted for confounders. The odds ratios for operative mortality varied widely between studies. Assuming a central estimate of the odds ratio of 0.54 (95% CI 0.05–6.24), the decision model estimated that the incremental cost per quality adjusted life year (QALY) was £74,580/QALY with a probability of 9 and 16% of being cost-effective at standard cost-effectiveness thresholds of £20,000/QALY and £30,000/QALY, respectively. The Expected Value of Perfect Information over 10 years at a threshold of £20,000/QALY was £11.2 million. Operative mortality contributed to most of the uncertainty in the decision model.

Conclusions

In the case of “maturing technologies”, decision modelling indicates the likely direction of costs and benefits and guides the development of further research projects. In our analysis of fEVAR versus OSR, decision uncertainty, particularly around operative mortality, might be effectively resolved by a short-term RCT, or possibly a well-conducted comparative observational study. Decision makers may consider that a conditional coverage decision is warranted with assessments required to make this type of recommendation depending on local priorities and circumstances.

Electronic supplementary material

The online version of this article (10.1186/s12962-018-0098-7) contains supplementary material, which is available to authorized users.

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.

Assessing the risk: Scoring systems for outcome prediction in emergency laparotomies

Emergency laparotomy is the commonest emergency surgical procedure in most hospitals and includes over 400 diverse surgical procedures. Despite the evolution of medicine and surgical practices, the mortality in patients needing emergency laparotomy remains abnormally high. Although surgical risk assessment first started with the ASA Physical Status score in 1941, efforts to find an ideal scoring system that accurately estimates the risk of mortality, continues till today. While many scoring systems have been developed, no single scoring system has been validated across multiple centers and geographical locations. While some scoring systems can predict the risk merely based upon preoperative findings and parameters, some rely on intra-operative assessment and histopathology reports to accurately stratify the risk of mortality. Although most scoring systems can potentially be used to compare risk-adjusted mortality across hospitals and amongst surgeons, only those which are based on preoperative findings can be used for risk prognostication and identify high-risk patients before surgery for an aggressive treatment. The recognition of the fact, that in the absence of outcome data in these patients, it would be impossible to evaluate the impact of quality improvement initiatives on risk-adjusted mortality, hospital groups and surgical societies have got together and started to pool data and analyze it. Appropriate scoring systems for emergency laparotomies would help in risk prognostication, risk-adjusted audit and assess the impact of quality improvement initiative in patient care across hospitals. Large multi-centric studies across varied geographic locations and surgical practices need to assess and validate the ideal and most apt scoring system for emergency laparotomies. While APACHE-II and P-POSSUM continue to be the most commonly used scoring system in emergency laparotomies,studies need to compare them in their ability to predict mortality and explore if either has a higher sensitivity and specificity than the other.

The impact of serum albumin and serum protein levels on POSSUM score of patients with proximal femur fractures

BACKGROUND

POSSUM was developed to predict risk-adjusted mortality and morbidity rates for surgical procedures. We evaluated the impact of serum albumin and serum protein levels on POSSUM scores.

METHODS

Medical files of 2269 patients operated for proximal femur fractures were reviewed. Preoperative serum albumin levels were available for 387 patients (mean 35.1g/l, range 22-49) and serum protein levels for 279 patients (mean 61.6g/l, range 40-86).

RESULTS

Serum albumin and protein levels were inversely associated with mortality in multivariate models (albumin, OR=0.89, p=0.009; protein, OR=0.92, p=0.009) and in composite outcome models as well (albumin, OR=0.955, p=0.219, protein, OR=0.94, p=0.014). The area under the curve (AUC) for POSSUM prediction of mortality (n=1770) was 0.632 (95% CI: 0.580-0.684, p<0.001). The AUC for a model including serum protein levels was 0.742 (95% CI: 0.649-0.834, p<0.001). Hospitalisation time was longer for patients with lower serum proteins levels (p=0.045), with an inverse correlation (Pearson correlation -0.164, p=0.011).

CONCLUSIONS

Lower preoperative serum albumin and serum protein levels were associated with increased risk for mortality, increased hospitalisation time and poorer outcomes in patients operated for proximal femoral fractures. Including those values to POSSUM scores would increase their predictive power.

Perioperative mortality and morbidity prediction using POSSUM, P-POSSUM and APACHE II in Chinese gastric cancer patients: surgical method is a key independent factor affecting prognosis

INTRODUCTION

Gastric cancer is the fourth most common cancer worldwide. Predicting morbidity and mortality is important in deciding timing of surgery and type of surgery offered. APACHE II, POSSUM, and P-POSSUM are the most reliable scoring methods in use today. This is the first paper to evaluate the utility of all three scoring systems in China.

METHODS

We collected data on 851 patients (583 male and 268 female) who underwent surgery between 1991 and 2011. Physiological and pathological data was entered in spreadsheet format and analyzed using STATA version 11.0 to generate ROC curves for each scoring system.

RESULTS

In predicting mortality, P-POSSUM and POSSUM were most effective and APACHE II was ineffective. POSSUM predicted a higher morbidity risk than was actually encountered. Age and type of operation were found to be independent risk factors for mortality.

DISCUSSION

The utility of the APACHE II score in gastric cancer patients is limited. APACHE II is suitable for considering group versus individual effect. The POSSUM score is useful in general surgery, but needs improvement. We found the P-POSSUM score to be superior for morbidity and mortality prediction. P-POSSUM is useful for both the general population and for a specific cohort. The type of surgery is a key decision point for surgeons, and independently affects prognosis. Based upon these findings and clinical scoring systems, clinicians can develop individualized treatment algorithms.

Comparison of fenestrated endovascular and open repair of abdominal aortic aneurysms not suitable for standard endovascular repair

BACKGROUND

Abdominal aortic aneurysms that are unsuitable for a standard endovascular repair (EVAR) could be considered for fenestrated endovascular repair (f-EVAR). The aim of this study was to conduct a risk-adjusted retrospective concurrent cohort comparison of f-EVAR and open repair for such aneurysms.

METHODS

All patients who underwent repair of an abdominal aortic aneurysm that was unsuitable for a standard EVAR due to inadequate neck within one institution between January 2006 and December 2010 were identified. Case notes were retrieved for clinical data, Vascular Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (V-POSSUM) score, and aneurysm morphology. Computed tomography scans were reviewed to establish aneurysm morphology.

RESULTS

A total of 107 patients were identified. The open surgery cohort included 54 patients (35 men) who were a median age of 72 years (interquartile range [IQR], 9.5; range, 60-86 years). The aortic cross-clamp was infrarenal in 20 patients, suprarenal or above in 21, and inter-renal in eight. Postoperatively, 63 major complications were noted in 30 patients, nine of whom required 16 reinterventions. Cumulative hospital stay of the cohort was 1170 days (median, 12; IQR, 13; range, 1-205 days) of which 234 days (median, 28; IQR, 36; range, 1-77 days) were in the intensive therapy unit (ITU). Perioperative mortality was 9.2% (n = 5), exactly as estimated by V-POSSUM. The f-EVAR cohort included 53 patients (47 men) who were a median age of 76 years (IQR, 11.50; range, 55-87 years). Two fenestrations and one scallop was the most frequent configuration (n = 31). Postoperatively, 37 major complications were noted in 18 patients, six requiring reintervention. Hospital stay was 559 days (median, 7; IQR, 4.5; range, 4-64 days), of which 31 days (median, 4; IQR, 10.5; range, 1-15 days) were in the ITU. Two patients died perioperatively (3.7%), resulting in an observed crude absolute risk reduction of 5.5% compared with open repair. The V-POSSUM estimated perioperative death in five patients (9.4%) in the f-EVAR cohort. In a hypothetic scenario of the f-EVAR cohort undergoing open repair, V-POSSUM estimated seven deaths (13.2%), resulting in an estimated risk-adjusted absolute risk reduction due to f-EVAR of 9.5%.

CONCLUSIONS

In this group of patients, f-EVAR reduced mortality and morbidity substantially compared with open repair and also reduced total hospital stay and ITU utilization.