Surgical audit using the POSSUM scoring tool in vascular surgery patients

Risk Prediction Models for Peri-Operative Mortality in Patients Undergoing Major Vascular Surgery with Particular Focus on Ruptured Abdominal Aortic Aneurysms: A Scoping Review

PURPOSE

The present scoping review aims to describe and analyze available clinical data on the most commonly reported risk prediction indices in vascular surgery for perioperative mortality, with a particular focus on ruptured abdominal aortic aneurysm (rAAA).

MATERIALS AND METHODS

A scoping review following the PRISMA Protocols Extension for Scoping Reviews was performed. Available full-text studies published in English in PubMed, Cochrane and EMBASE databases (last queried, 30 March 2023) were systematically reviewed and analyzed. The Population, Intervention, Comparison, Outcome (PICO) framework used to construct the search strings was the following: in patients with aortic pathologies, in particular rAAA (population), undergoing open or endovascular surgery (intervention), what different risk prediction models exist (comparison), and how well do they predict post-operative mortality (outcomes)?

RESULTS

The literature search and screening of all relevant abstracts revealed a total of 56 studies in the final qualitative synthesis. The main findings of the scoping review, grouped by the risk score that was investigated in the original studies, were synthetized without performing any formal meta-analysis. A total of nine risk scores for major vascular surgery or elective AAA, and 10 scores focusing on rAAA, were identified. Whilst there were several validation studies suggesting that most risk scores performed adequately in the setting of rAAA, none reached 100% accuracy. The Glasgow aneurysm score, ERAS and Vancouver score risk scores were more frequently included in validation studies and were more often used in secondary studies. Unfortunately, the published literature presents a heterogenicity of results in the validation studies comparing the different risk scores. To date, no risk score has been endorsed by any of the vascular surgery societies.

CONCLUSIONS

The use of risk scores in any complex surgery can have multiple advantages, especially when dealing with emergent cases, since they can inform perioperative decision making, patient and family discussions, and post hoc case-mix adjustments. Although a variety of different rAAA risk prediction tools have been published to date, none are superior to others based on this review. The heterogeneity of the variables used in the different scores impairs comparative analysis which represents a major limitation to understanding which risk score may be the "best" in contemporary practice. Future developments in artificial intelligence may further assist surgical decision making in predicting post-operative adverse events.

Physiologic risk stratification is important to long-term mortality, complications, and readmission in thoracic endovascular aortic repair

Use of the American Society of Anesthesiologists (ASA) physical status classification is important for periprocedural risk stratification. However, the collective effect after adjustment for the Society for Vascular Surgery (SVS) medical comorbidity grading system on long-term all-cause mortality, complications, and discharge disposition is unknown. We examined these associations in patients after thoracic endograft placement. Data from three thoracic endovascular aortic repair (TEVAR) trials through 5 years of follow-up were included. Patients with acute complicated type B dissection (n = 50), traumatic transection (n = 101), or descending thoracic aneurysm (n = 66) were analyzed. The patients were stratified into three groups according to the ASA class: I-II, III, and IV. Multivariable proportional hazards regression models were used to examine the effect of ASA class on 5-year mortality, complications, and rehospitalizations after adjustment for SVS risk score and potential confounders. The largest proportion of patients treated by TEVAR across the ASA groups (n = 217) was ASA IV (n = 97; 44.7%; P < .001), followed by ASA III (n = 83; 38.2%) and ASA I-II (n = 37; 17.1%). Among the ASA groups, the ASA I-II patients were, on average, 6 years younger than those with ASA III and 3 years older than those with ASA IV (ASA I-II: age, 54.3 ± 22.0 years; ASA III: age, 60.0 ± 19.7 years; ASA IV: age, 51.0 ± 18.4 years; P = .009). Multivariable adjusted 5-year outcome models showed that ASA class IV, independent of the SVS score, conferred an increased risk of mortality (hazard ratio [HR], 3.83; 95% confidence interval [CI], 1.19-12.25; P = .0239) and complications (HR, 4.53; 95% CI, 1.69-12.13; P = .0027) but not rehospitalization (HR, 1.84; 95% CI, 0.93-3.68; P = .0817) compared with ASA class I-II. Procedural ASA class is associated with long-term outcomes among post-TEVAR patients, independent of the SVS score. The ASA class and SVS score remain important to patient counseling and postoperative outcomes beyond the index operation.

A novel risk score for in-hospital perioperative mortality of five major surgeries

BACKGROUND

Risk-scoring tools for perioperative mortality adjustment are essential for inter-hospital quality comparisons, which are still lacking in China. Existing scores had significant disadvantages when applied in managerial practice.

OBJECTIVE

This study aimed to develop a simple risk score using highly accessible information that could appropriately adjust the perioperative mortality from major surgeries across tertiary Chinese public hospitals and provide a reference for other underdeveloped countries with the same need.

METHODS

A study cohort from 19 hospitals was randomly split into a development set and an internal validation set in the ratio of 7:3. Another cohort from six hospitals was used as an external validation set. All data were obtained from the military-hospital public services database of the National Engineering Laboratory of Application Technology in Medical Big Data. Patients aged above 18 years undergoing one of the five categories of major surgical procedures between 1 January 2010 and 31 December 2020 were identified. The multivariate logistic regression analysis was used to predict the risk of mortality and derive the risk score. The area under the receiver operating characteristic curve (AUC) and the Hosmer-Lemeshow goodness-of-fit test were used to assess the discrimination and calibration of the model, respectively.

RESULTS

The study set included 45 558 cases, divided into a development set containing 31 891 cases and an internal validation set with 13 667 cases. Another cohort with 14 956 cases was used as an external validation set. The final included predictor variables were age, Elixhauser Comorbidity Index, condition at admission, admission route and the procedure. The predicted risk score ranged from -21.5 to 37.0 points. The model discriminated well in the development set, internal validation set, and external validation set. The AUC for them were 0.753 (Standard Error(SE) 0.016, 95% Confidence Interval(CI): 0.721,0.784), 0.790 (SE 0.025, 95% CI: 0.742,0.839), and 0.766(SE 0.019, 95% CI: 0.728, 0.804), respectively. P values in the Hosmer-Lemeshow goodness-of-fit test were all above 0.05, indicating a good calibration.

CONCLUSIONS

This risk-scoring model was proved to have satisfactory performance, allowing the rapid and effective risk adjustment of perioperative mortality when comparing the surgical quality in tertiary hospitals in China and other underdeveloped regions.

Multimodal intraoperative monitoring: an observational case series in high risk patients undergoing major peripheral vascular surgery

Recent guidelines from the National Institute of Health and Care Excellence (NICE) and the UK National Health Service (NHS) have stipulated that intraoperative flow monitoring should be used in high-risk patients undergoing major surgery to improve outcomes and reduce costs. Depth of anaesthesia monitoring is also recommended for patients where excessive anaesthetic depth is poorly tolerated, along with cerebral oximetry in patients with proximal femoral fractures. The aims of this descriptive case series were to evaluate the impact of a multimodal intraoperative strategy and its effect on mortality and amputation rate for patients with critical leg ischaemia. In an observational case series, 120 elderly patients undergoing major infra-inguinal bypass between 2007 and 2012 were included in this retrospective analysis of prospectively collected data. Nominal cardiac output (nCO, LiDCOrapid, LiDCO Ltd, UK), bispectral index to monitor depth of anaesthesia (BIS, Covidien, USA) and cerebral oxygenation, rSO2 (Invos, Covidien, USA) readings were obtained before induction of general anaesthesia and throughout surgery. 30 day, 1-year mortality and amputation rates were analysed. Demographics and physiological parameters including correlation with V-POSSUM, age, gender and other co-morbidities were statistically analysed. Thirty-day mortality rate was 0.8% (n = 1). V-POSSUM scoring indicated a predicted mortality of 9%. Amputation rate was less than 2% at one year. Only 8% of patients (10 of 120) were admitted to a high dependency unit (HDU) postoperatively. 30-day mortality in our case series was lower than predicted by V-POSSUM scoring. Use of multimodal intraoperative monitoring with the specific aim of limiting build-up of oxygen debt should be subjected to a randomised controlled study to assess the reproducibility of these results.