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

Predicting Long-Term Survival after Endovascular Aneurysm Repair Using Machine Learning-Based Decision Tree Analysis

ObjectiveEndovascular aneurysm repair (EVAR) has become a preferred method for treating abdominal aortic aneurysms (AAA) due to its minimally invasive approach. However, identifying factors that influence long-term patient outcomes is crucial for improving prognosis. This study investigates whether machine learning (ML)-based decision tree analysis (DTA) can predict long-term survival (over 5 years postoperatively) by uncovering complex patterns in patient data.MethodsWe retrospectively analyzed data from 142 patients who underwent elective EVAR for AAA at Tokyo Medical University Hospital between October 2013 and July 2018. The dataset comprised 24 variables, including age, gender, nutritional status, comorbidities, and surgical details. The decision tree classifier was developed and validated using Python 3.7 and the scikit-learn toolkit.ResultsDTA identified poor nutritional status as the most significant predictor, followed by compromised immunity, active cancer, octogenarians, chronic kidney disease, and chronic obstructive pulmonary disease. The decision tree identified 9 terminal nodes with probabilities of long-term survival. Four of these terminal nodes represented groups of patients with a high probability of long-term survival: 100%, 84%, 77%, and 60%, whereas the other 5 terminal nodes represented groups of patients with a low probability of long-term survival: 17%, 25%, 30%, 45%, and 47%. The model achieved a moderately high accuracy of 76.1%, specificity of 72.4%, sensitivity of 81.8%, precision of 65.2%, and area under the receiver operating characteristic curve of 0.84.ConclusionML-based DTA effectively predicts long-term survival after EVAR, highlighting the importance of comprehensive preoperative assessments and personalized management strategies to improve patient outcomes.

Impact of patient sex on selection for abdominal aortic aneurysm repair: a discrete choice experiment

OBJECTIVES

Women with an abdominal aortic aneurysm (AAA) are less likely to receive elective repair than men. This study explored the effect of patient sex and other attributes on vascular surgeons' decision-making for infrarenal AAA repair.

DESIGN

Discrete choice experiment.

SETTING

Simulated environment using case scenarios with varying patient attributes.

PARTICIPANTS

Vascular surgeons.

INTERVENTIONS

Surgical decision-making.

MAIN OUTCOME MEASURES

AAA repair versus no repair and endovascular versus open repair.

RESULTS

182 surgeons completed 2987 scenarios. When all other attributes were equal, a woman was more likely to be offered an AAA repair (marginal rate of substitution (MRS) 3.86 (95% CI 2.93, 4.79)), while very high anaesthetic risk (MRS -4.33 (95% CI -5.63, -3.03)) and hostile anatomy (MRS -3.28 (95% CI -4.55, -2.01)) were deterrents. Increasing age did not adversely affect the likelihood of offering repair to men but decreased the likelihood for women, which negated women's selection advantage from the age of 83 years. Women were also more likely to be offered endovascular repair (MRS 2.57 (95% CI 1.30, 3.84)).

CONCLUSIONS

Patient sex alone did not account for real-world disparity observed in selection for surgery. Rather, being a woman was associated with a higher likelihood of being offered AAA repair but also a higher likelihood of being offered less invasive endovascular repair. Increased age decreased the likelihood of surgical selection for women but not men. Preference for less invasive repair, combined with inferior rates of anatomical suitability, and the comparably older age of women at the time of AAA repair selection may account for lower rates of repair for women observed.

Outcomes of elective open surgical repair or fenestrated endovascular aneurysm repair for juxtarenal abdominal aortic aneurysms in Sweden

BACKGROUND

A juxtarenal abdominal aortic aneurysm is defined as a short (less than 4 mm) or no-neck aneurysm, which is often treated with open or complex endovascular repair. The evidence to support the best treatment strategy is scarce. The aim of this study was to assess the short- and mid-term outcomes of elective open surgical repair or fenestrated endovascular aneurysm repair for juxtarenal abdominal aortic aneurysms in Sweden.

METHODS

Patients who underwent elective open surgical repair or fenestrated endovascular aneurysm repair for juxtarenal abdominal aortic aneurysms between 2018 and 2021 were identified in the Swedish Vascular Registry. Demographics, practice patterns, and operative details were assessed. The primary outcome was 30-day mortality. Secondary outcomes included perioperative complications and mid-term survival.

RESULTS

Among 3777 aortic aneurysm repairs performed, 418 involved juxtarenal abdominal aortic aneurysms (open surgical repair 228 (54.5%), fenestrated endovascular aneurysm repair 176 (42.1%), chimney endovascular aneurysm repair 6 (1.4%), and branched endovascular aneurysm repair 8 (1.9%)). Some 25 centres performed juxtarenal abdominal aortic aneurysm repairs with open surgical repair and fenestrated endovascular aneurysm repair. The caseload varied from 2 to 54 repairs per centre. The mean aneurysm diameter was 61 mm. Endovascularly treated patients were older and had more pulmonary co-morbidities. The 30-day mortality rate was 2.2% (open surgical repair 2.6% and fenestrated endovascular aneurysm repair 1.7%; P = 0.397). Perioperative major complications occurred in 14.1% of patients (open surgical repair 19.3% and fenestrated endovascular aneurysm repair 7.4%; P < 0.001) and perioperative vascular complications occurred in 12.1% of patients (open surgical repair 8.8% and fenestrated endovascular aneurysm repair 11.9%; P = 0.190). The survival rate (estimated using Kaplan-Meier analysis) at 1 year and 3 years was 93.1% and 85.9% respectively for open surgical repair and 95.2% and 80.9% respectively for fenestrated endovascular aneurysm repair (P = 0.477).

CONCLUSION

This nationwide study reveals considerable variations in volume and treatment strategy between Swedish centres performing juxtarenal abdominal aortic aneurysm repairs. Survival is comparable for open surgical repair and fenestrated endovascular aneurysm repair, although there are significant baseline demographic differences between patients selected for the two treatment modalities.

The Impact of Body Composition on Mortality and Hospital Length of Stay after Endovascular and Open Aortic Aneurysm Repair: A Retrospective Cohort Study

Background: Sarcopenia is an indicator of preoperative frailty and a patient-specific risk factor for poor prognosis in elderly surgical patients. Some studies have explored the prognostic significance of body composition parameters in relation to perioperative mortality after aortic repair and to mid- and long-term survival following endovascular aneurysm repair (EVAR). This study aimed to comprehensively investigate the effects of various body composition parameters, including but not limited to sarcopenia, on short- and long-term mortality as well as the length of hospital stay in two large cohorts of patients undergoing open surgical aortic repair (OSR) or EVAR. Methods: A single-institution retrospective cohort study included patients who underwent EVAR or OSR from January 2010 to December 2017. Several parameters of body composition on axial CT angiography images were analyzed, such as skeletal muscle area (SMA) with derived skeletal muscle index (SMI), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT). Results: 477 patients were included: 250 treated by OSR and 227 by EVAR; the mean age was 70.8 years (OSR) and 76.3 years (EVAR), with a mean follow-up of 54 months. Sarcopenia was associated with a prolonged length of hospital stay in EVAR patients but not in OSR patients (β coefficient 3.22; p-value 0.022 vs. β coefficient 0.391; p-value 0.696). Sarcopenia was an elevated one-year mortality risk post-EVAR compared to those without sarcopenia (p-value for the log-rank test 0.05). SMA and SMI were associated with long-term mortality in EVAR patients even after adjusting for multiple confounders (HR 0.98, p-value 0.003; HR 0.97, p-value 0.032). The analysis of the OSR cohort did not show a significant correlation between short- and long-term mortality and sarcopenia indicators. Conclusions: The results suggest that body composition could predict increased mortality and longer hospital stays in patients undergoing EVAR procedures. These findings were not confirmed in the cohort of patients who underwent OSR. Patients with sarcopenia and pre-operative malnutrition should be critically assessed to define the indication for treatment in this predominantly elderly and morbid cohort, despite EVAR procedures being less invasive. Body composition evaluation is an inexpensive and reproducible tool that can contribute to an improved decision-making process by identifying patients who will benefit most from EVAR, ensuring a more personalized and cost-effective treatment strategy. Further studies are planned to explore the added value of integrating body composition into a comprehensive risk stratification before aortic surgery.

C-reactive protein to albumin ratio provides important long-term prognostic information in patients undergoing endovascular abdominal aortic repair

BACKGROUND

The prognostic value of C-reactive protein/albumin ratio (CAR) is of import in cardiovascular diseases. Our aim was to evaluate the impact of the CAR in patients with asymptomatic abdominal aortic aneurysm (AAA) undergoing endovascular aneurysm repair (EVAR).

MATERIAL AND METHOD

We retrospectively evaluated 127 consecutive patients who underwent technically successful elective EVAR procedure between December 2014 and September 2020. The optimal CAR cut-off value was determined by using receiver operating characteristic (ROC) curve analysis. Based on the cut-off value, we investigated the association of CAR with long-term all-cause mortality.

RESULTS

32 (25.1%) of the patients experienced all-cause mortality during a mean 32.7 ± 21.7 months' follow-up. In the group with mortality, CAR was significantly higher than in the survivor group (4.63 (2.60-11.88) versus 1.63 (0.72-3.24), p < 0.001). Kaplan-Meier curves showed a higher incidence of all-cause mortality in patients with high CAR compared to patients with low CAR (log-rank test, p < 0.001). Multivariable Cox regression analysis revealed that glucose ≥ 110 mg/dL (HR: 2.740; 95% CI: 1.354-5.542; p = 0.005), creatinine ≥ 0.99 mg/dL (HR: 2.957, 95% CI: 1.282-6.819, p = 0.011) and CAR > 2.05 (HR: 8.190, 95% CI: 1.899-35.320, p = 0.005) were the independent predictors of mortality.

CONCLUSION

CAR was associated with a significant increase in postoperative long-term mortality in patients who underwent EVAR. Preoperatively calculated CAR can be used as an important prognostic factor.

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.

Prognostic model for survival of patients with abdominal aortic aneurysms treated with endovascular aneurysm repair

The role of endovascular aneurysm repair (EVAR) in patients with asymptomatic abdominal aortic aneurysm (AAA) who are unfit for open surgical repair has been questioned. The impending risk of aneurysm rupture, the risk of elective repair, and the life expectancy must be balanced when considering elective AAA repair. This retrospective observational cohort study included all consecutive patients treated with standard EVAR for AAA at a referral centre between 2001 and 2020. A previously published predictive model for survival after EVAR in patients treated between 2001 and 2012 was temporally validated using patients treated at the same institution between 2013 and 2020 and updated using the overall cohort. 558 patients (91.2% males, mean age 74.9 years) were included. Older age, lower eGFR, and COPD were independent predictors for impaired survival. A risk score showed good discrimination between four risk groups (Harrel's C = 0.70). The 5-years survival probabilities were only 40% in "high-risk" patients, 68% in "moderate-to-high-risk" patients, 83% in "low-to-moderate-risk", and 89% in "low-risk" patients. Low-risk patients with a favourable life expectancy are likely to benefit from EVAR, while high-risk patients with a short life expectancy may not benefit from EVAR at the current diameter threshold.

Glasgow Aneurysm Score: a predictor of long-term mortality following endovascular repair of abdominal aortic aneurysm?

BACKGROUND

To evaluate the value of Glasgow Aneurysm Score (GAS) in predicting long-term mortality and survival in patients who have undergone endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA).

METHODS

A retrospective single-center study of 257 patients with non-ruptured AAA undergoing EVAR between January 2013 and 2021. GAS scores were compared between the survivors (group 1) and the long-term mortality (group 2) groups. Cox regression analysis was used to determine independent predictors of late mortality. Receiver operating characteristic curve (ROC) analysis was used to determine the optimum cut-off values of GAS values to determine the effect on late-mortality. Survival analysis was conducted using Kaplan-Meier.

RESULTS

The study included 257 patients with a mean age of 69.75 ± 7.75 (46-92), who underwent EVAR due to AAA. Average follow up period was 18.98 ± 22.84 months (0-88). Fourty-five (17.8%) mortalities occured during long-term follow-up. A past medical history of cancer resulted in a 2.5 fold increase in risk of long-term mortality (OR: 2.52, 95% CI 1.10-5.76; p = 0.029). GAS values were higher in group 2 compared to group 1 (81.02 ± 10.33 vs. 73.73 ± 10.46; p < 0.001). The area under the ROC curve for GAS was 0.682 and the GAS cut-off value was 77.5 (specificity 64%, p < 0.001). The mortality rates in patients with GAS < 77.5 and GAS > 77.5 were: 12.8% and 24.8% respectively (p = 0.014). Every 10 point increase in GAS resulted in approximately a 2 fold increase in risk of long-term mortality (OR: 1.8, 95% CI 1.3-2.5; p < 0.001). Five year survival rates in patients with GAS < 77.5 and > 77.5 were 75.7% and 61.7%, respectively (p = 0.013).

CONCLUSIONS

The findings of our study suggests that an increase in GAS score may predict long-term mortality. In addition, the mortality rates in patients above the GAS cut-off value almost doubled compared to those below. Furthermore, the presence of a past history of cancer resulted in a 2.5 fold increase in long-term mortality risk. Addition of cancer to the GAS scoring system may be considered in future studies. Further studies are necessary to consolidate these findings.

[Pro Endo: No Need for Open Any More... Surveillance is All Important]

Since its first report in 1991, endovascular aneurysm repair (EVAR) has become an established and preferred treatment modality for many patients. Several randomised controlled trials comparing EVAR and open repair have shown an early survival benefit, lower perioperative morbidity and shorter hospital stay with EVAR. As a result, EVAR has become the most common method of elective repair of BAAs in most vascular centres. Despite its widespread use, there are still subgroups of the patient population for whom the benefit of EVAR has not been clearly demonstrated. The most frequently discussed subgroup in this context is the patient with few risk factors - due to concerns about the durability and need of reinterventions. EVAR can provide durability and long-term survival similar to open repair in these younger patients, as long as the aneurysm anatomy and instructions for use are followed. The evidence on the effects of follow-up on patient survival is currently controversial. With increasing knowledge about the behavior of endoprostheses and factors that influence the complications of the endograft, changes in follow-up protocols have been made. A more patient-specific follow-up strategy and less compliance with a rigorous follow up scheme are required.

Abdominal aortic aneurysm and acute appendicitis: a case report and review of the literature

Background

Abdominal aortic aneurysm and acute appendicitis occur relatively frequently in elderly patients. However, the co-occurrence of the two pathologies is very rare and serious.

Case presentation

We present the case of an elderly Caucasian patient who was aware of having an abdominal aortic aneurysm but refused treatment and was subsequently admitted to the hospital’s emergency department with acute abdominal symptoms. A computed tomography scan raised the possibility of complication due to the characteristics of the aneurysm. The patient then agreed to emergency surgery. Laparotomy revealed the existence of an acute perforated appendicitis with a significant abscess in the right iliac fossa and an uncomplicated aneurysm. Appendectomy was performed and the abscess drained. The postoperative period passed without complications, and the patient again refused surgery for the aneurysm, which due to its anatomical characteristics was not a candidate for standard endovascular treatment.

Conclusions

In light of this experience, we review the literature about the relationship between abdominal aortic aneurysm and acute appendicitis.

Prognostic Value of Inflammatory Biomarkers in 5-Year Survival After Endovascular Repair of Abdominal Aortic Aneurysms in a Predominantly Male Cohort: Implications for Practice

BACKGROUND

Prognostic factors of long-term survival can guide selection of patients for endovascular repair of abdominal aortic aneurysms (EVAR). The aim of this study was to evaluate the relationship between the neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), the lymphocyte-to-monocyte ratio (LMR) and the systemic immune-inflammation index (SIII) with survival after EVAR and to assess whether the addition of these biomarkers improved the prediction of survival after surgery.

METHODS

Retrospective analysis of 284 consecutive patients who underwent an EVAR at a single institution. The association between biomarkers and survival was explored using generalized additive models with penalized smoothing splines and multivariate Cox models. C-statistics and continuous net reclassification indexes (c-NRI) were used to assess the improvement in prediction.

RESULTS

Survival rates at 2 and 5 years were 83.9% and 66.2%, respectively. The predictive score of survival included hemoglobin (HR = 0.849, p = 0.004), statin intake (HR = 0.538, p = 0.004), atrial fibrillation (HR = 2.515, p < 0.001), heart failure (HR = 2.542, p = 0.017) and the non-revascularized coronary artery disease (HR = 2.163, p = 0.004). Spline analyses showed a linear relationship between survival and NLR, PLR, LMR and SII. After adjusting for the predictive score, there was an independent relationship between survival and NLR (HR = 1.072, p = 0.006), PLR (HR = 1.002, p = 0.014) and SII (HR = 1.000, p = 0.043). However, only the addition of NLR improved moderately the c-NRI. A NLR ≥ 3 was independently associated with lower survival rates at 2-years (HR 1.98; 95% CI 1.07-3.66) and 5-years (HR 1.84, 95% CI 1.22-2.78) of follow-up.

CONCLUSIONS

Most inflammatory biomarkers are linear and independently associated with survival after EVAR, but only the NLR improved moderately the prediction of a survival score. Therefore, a NLR ≥ 3 may be used to identify patients with a low survival rate and help in decision-making.

Predictors of Operative Mortality of 928 Intact Aortoiliac Aneurysms

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Endovascular Aneurysm Repair May Provide a Survival Advantage in Patients Deemed Physiologically Ineligible for Open Abdominal Aortic Aneurysm Repair

BACKGROUND

Cardiopulmonary exercise testing (CPET) provides an objective assessment of functional capacity and fitness. It can be used to guide decision making prior to major vascular surgery. The EVAR-2 trial suggested that endovascular aneurysm repair (EVAR) in patients unfit for open repair failed to provide a significant survival advantage over nonsurgical management. The aim of this study is to assess contemporary survival differences between patients with poor CPET measures who underwent EVAR or were not offered surgical intervention.

METHODS

A prospectively maintained database of CPET results of patients considered for elective infrarenal aortic aneurysm repair were interrogated. Anaerobic threshold (AT) of <11 mL/min/kg was used to indicate poor physical fitness. Hospital electronic records were then reviewed for perioperative, reintervention, and long-term outcomes.

RESULTS

Between November 2007 and October 2017, 532 aortic aneurysm repairs were undertaken, of which 376 underwent preoperative CPET. Seventy patients were identified as having an AT <11 mL/min/kg. Thirty-seven patients underwent EVAR and 33 were managed nonsurgically. All-cause survival at 1, 3, and 5 years for those patients who underwent EVAR was 97%, 92%, and 81%, respectively. For those not offered surgical intervention survival at the same points was 72%, 48%, and 24% [hazard ratio, HR = 5.13 (1.67-15.82), P = 0.004]. Aneurysm-specific survival at 1, 3, and 5 years for those patients who underwent EVAR was 97%, 94%, and 94%, respectively. Survival at the same time points for those not offered surgical intervention was 90%, 69%, and 39%, respectively [HR = 7.48 (1.37-40.82), P = 0.02].

CONCLUSIONS

In this small, retrospective, single-center, nonrandomized cohort, EVAR may provide a survival advantage in patients with poor physical fitness identified via CPET. Randomized studies with current generation EVAR are required to validate the results shown here.

Influence of psoas muscle area on mortality following elective abdominal aortic aneurysm repair

BACKGROUND

The effect of sarcopenia based on the total psoas muscle area (TPMA) on CT is inconclusive in patients undergoing abdominal aortic aneurysm (AAA) intervention. The aim of this prospective cohort study was to evaluate morphometric sarcopenia as a method of risk stratification in patients undergoing elective AAA intervention.

METHODS

TPMA was measured on preintervention CT images of patients undergoing elective endovascular aneurysm repair (EVAR) or open aneurysm repair. Mortality was assessed in relation to preintervention TPMA using Cox regression analysis, with calculation of hazard ratios at 30 days, 1 year and 4 years. Postintervention morbidity was evaluated in terms of postintervention care, duration of hospital stay and 30-day readmission. Changes in TPMA on surveillance EVAR imaging were also evaluated.

RESULTS

In total, 382 patient images acquired between March 2008 and December 2016 were analysed. There were no significant intraobserver and interobserver differences in measurements of TPMA. Preintervention TPMA failed to predict morbidity and mortality at all time points. The mean(s.d.) interval between preintervention and surveillance imaging was 361·3(111·2) days. A significant reduction in TPMA was observed in men on surveillance imaging after EVAR (mean reduction 0·63(1·43) cm2 per m2 ; P < 0·001). However, this was not associated with mortality (adjusted hazard ratio 1·00, 95 per cent c.i. 0·99 to 1·01; P = 0·935).

CONCLUSION

TPMA is not a suitable risk stratification tool for patients undergoing effective intervention for AAA.

Prevalence of Elective and Ruptured Abdominal Aortic Aneurysm Repairs by Age and Sex From 2003 to 2016 in Ontario, Canada

IMPORTANCE

Age and sex are important considerations in assessing and individualizing therapy for abdominal aortic aneurysm (AAA) repair.

OBJECTIVE

To determine the prevalence of open and endovascular elective AAA (EAAA) and ruptured AAA (RAAA) repair by age and sex.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective, population-based, cross-sectional, time-series analysis in Ontario, Canada, from April 1, 2003, to March 31, 2016, all patients undergoing AAA repair who were older than 39 years were included.

EXPOSURES

Elective AAA and RAAA repair with open surgical repair (OSR) or endovascular aortic repair (EVAR).

MAIN OUTCOMES AND MEASURES

Age- and sex-standardized rates of EAAA and RAAA repair with OSR and EVAR.

RESULTS

From 2003 to 2016, 19 489 EAAA repairs (12 232 [63%] OSR and 7257 [37%] EVAR) and 2732 RAAA repairs (2466 [90%] OSR and 266 [10%] EVAR) were identified. The mean (SD) age was 72.7 (8.1) years in the EAAA subgroup and 73.5 (8.9) years in the RAAA subgroup; 15 813 patients (81%) in the EAAA subgroup and 2178 (80%) in the RAAA subgroup were men. The rates of EAAA by age quintile and sex decreased over the study period except among patients older than 79 years (1.3 per 100 000 population in 2003 to 2.2 per 100 000 population in 2016; 70% increase; P < .001). The rates of elective OSR decreased across all age and sex subgroups (range, 38%-74% decrease; P ≤ .009 for all subgroups) except among patients older than 79 years (1.3 per 100 000 population at baseline to 0.56 per 100 000 population in the second quarter of 2016; 53% decrease; P = .05). The rates of elective EVAR significantly increased across all age and sex subgroups (range, 566%-1585% increase; P ≤ .04 for all subgroups). Elective EVAR became the dominant treatment approach for aneurysms in men around 2010, whereas it maintained parity among women in 2016. The RAAA repair rate decreased over the study period in all subgroups (range, 32%-91% decrease; P ≤ .001 for all subgroups), but the decrease was not significant among women (80% decrease; P = .08). Similarly, the rates of ruptured OSR decreased among all subgroups (range, 47%-91% decrease; P < .001), but the decrease was not significant among women (87% decrease; P = .54). Ruptured EVAR showed significant uptake in all subgroups.

CONCLUSIONS AND RELEVANCE

Among patients with AAA in Ontario, Canada, use of EVAR appeared to increase from 2003 to 2016, whereas OSR use appeared to decrease. These findings were most pronounced among elective procedures for men and older patients. The delayed increase in the use of EVAR among women may reflect continued anatomical constraints for women seeking elective repair.

A Risk Stratification Model for Cardiovascular Complications during the 3-Month Period after Major Elective Vascular Surgery

Introduction

The Revised Cardiac Risk Index (RCRI) is an extensively used simple risk stratification tool advocated by the European Society of Cardiology and European Society of Anesthesiology (ESC/ESA).

Purpose

The aim of this study was to find the best model for predicting 3-month cardiovascular complications in elective major vascular surgical patients using preoperative clinical assessment, calculation of the RCRI and Vascular Physiological and Operative Severity Score for the enumeration of mortality and morbidity (V-POSSUM) scores, and the preoperative levels of N-terminal brain natriuretic peptide (NT pro-BNP), high-sensitivity troponin I (hs TnI), and high-sensitivity C-reactive protein (hs CRP).

Materials and Methods

We included 122 participants in a prospective, single-center, observational study. The levels of NT pro-BNP, hs CRP, and hs TnI were measured 48 hours prior to surgery. During the perioperative period and 90 days after surgery the following adverse cardiac events were recorded: myocardial infarction, arrhythmias, pulmonary edema, acute decompensated heart failure, and cardiac arrest.

Results

During the first 3 months after surgery 29 participants (23.8%) had 50 cardiac complications. There was a statistically significant difference in the RCRI score between participants with and without cardiac complications. ROC analysis showed that a combination of RCRI with hs TnI has good discriminatory power (AUC 0.909, p<0,001). By adding NT pro-BNP concentrations to the RCRI+hs TnI+V-POSSSUM combination we obtained the model with the best predictive power for 3-month cardiac complications (AUC 0.963, p<0,001).

Conclusion

We need to improve preoperative risk assessment in participants scheduled for major vascular surgery by combining their clinical scores with biomarkers. Therefore, it is possible to identify patients at risk of cardiovascular complications who need adequate preoperative diagnosis and treatment.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Long-term Comparison of Endovascular and Open Repair of Abdominal Aortic Aneurysms: Retrospective Analysis of Matched Cohorts with Propensity Score

BACKGROUND

Although recent guidelines recommend endovascular aneurysm repair (EVAR) for robust younger patients, we have been limiting our indication to older patients or those who are physically frail. This study compares long-term outcomes of our series of abdominal aortic aneurysms (AAAs) treated with endovascular repair (ER) and open surgery (OS), using propensity score matching.

METHODS

Between June 2007 and October 2014, 819 patients with infrarenal AAA underwent elective repair at our institution. Among them, 737 patients (386 ERs and 351 OSs) with over 1-year follow-up or any events (reintervention or mortality) were enrolled. Covariates for matching included age, sex, hypertension, coronary arterial disease, obstructive pulmonary disease, diabetes, stroke, malignancy, hemodialysis, ejection fraction, serum creatinine, and respiratory function.

RESULTS

After propensity score matching, 157 pairs were selected. In the original cohort, overall survival at 5 years was 84.1% in ER and 89.3% in OS; the difference was significant (P = 0.019). The freedom-from-reintervention rates at 5 years were also significantly different, 81.8% in ER and 92.8% in OS (P = 0.007). In the matched cohort, age and comorbidities were similar both in ER and OS. The overall survival at 5 years was 85.4% and 90.1% in ER and OS, respectively; the difference was not significant (P = 0.242). The freedom-from-reintervention rates at 5 years were 81.1% in ER and 89.1% in OS; these were also not significantly different (P = 0.178).

CONCLUSIONS

Risk-adjusted comparisons revealed that long-term outcomes of ER and OS were comparable among our relatively frail patients in their age 70s. Our results failed to show the long-term advantage of EVAR in rather high-risk patients and provided no supportive evidence for our selection criteria.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Introduction:

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

Objective:

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

Methods:

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

Results:

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

Conclusion:

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

Assessing the Stability of Aortic Aneurysms with Pulse Wave Imaging

Purpose To assess whether the stability of murine aortic aneurysms is associated with the homogeneity of pulse wave propagation within the saccular wall. Materials and Methods All animal procedures were approved by the institutional Animal Care and Use Committee. Apolipoprotein E and tissue inhibitor of metalloproteinases-1 knockout mice (n = 26) were infused with angiotensin II by using subcutaneously implanted osmotic pumps, with an additional control mouse used for histologic examination (n = 1). Pulse wave imaging (PWI) was performed just before infusion and 15 days after infusion by using 40-MHz ultrasonography at 8000 frames per second (with electrocardiographic gating). Aneurysm appearance on B-mode images was monitored every 2-3 days for 30 days. On the basis of B-mode images obtained after 30 days, aneurysms were deemed to have been unstable if they had ruptured; otherwise, they were deemed stable. Statistical significance was assessed by using two-tailed t tests. Results In normal aortas, the pulse waves propagated at relatively constant velocities (mean ± standard deviation, 2.8 m/sec ± 0.9). Fifteen days after infusion, all mice had developed aneurysms, with significant (P < .001/12) changes in maximum anterior-posterior diameter (increase of 54.9% ± 2.5) and pulse wave velocity (PWV) (decrease of 1.3 m/sec ± 0.8). While there was no significant difference in these parameters (P = .45 for diameter and P = .55 for PWV) between stable aneurysms (n = 12) and unstable aneurysms (n = 14), the standard deviation of the high-resolution PWV was significantly higher (P < .001/12) in unstable aneurysms (5.7 m/sec ± 1.6) than in stable ones (3.2 m/sec ± 0.9). Conclusion High-resolution PWI was used to measure the local homogeneity of pulse wave propagation within the saccular wall, which is lower in unstable aneurysms than in stable ones. Hence, if proven to add additional information beyond size and appearance in human studies, PWI could potentially be used to assess the stability of aneurysms by providing information that is complementary to the anatomic data obtained with conventional B-mode imaging. ^© RSNA, 2016 Online supplemental material is available for this article.

Late Sac Behavior after Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm

BACKGROUND

Sac behavior after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) is considered as a surrogate for the risk of late rupture. The purpose of the study is to assess the sac behavior of AAAs after EVAR.

METHODS AND RESULTS

Late sac enlargement (LSE) (≥5 mm) and late sac shrinkage (LSS) (≥5 mm) were analyzed in 589 consecutive patients who were registered at 14 national centers in Japan. The proportions of patients who had LSE at 1, 3 and 5 years were 2.6% ± 0.7%, 10.0% ± 1.6% and 19.0% ± 2.9%. The proportions of patients who had LSS at 1, 3 and 5 years were 50.1% ± 0.7%, 59.2% ± 2.3% and 61.7% ± 2.7%. Multiple logistic regression analysis identified two variables as a risk factor for LSE; persistent endoleak (Odds ratio 9.56 (4.84-19.49), P <0.001) and low platelet count (Odds ratio 0.92 (0.86-0.99), P = 0.0224). The leading cause of endoleak in patients with LSE was type II.

CONCLUSIONS

The incidence of LSE is not negligible over 5 year period. Patients with persistent endoleak and/or low platelet count should carefully be observed for LSE.

CLINICAL TRIAL REGISTRATION

UMIN-CTR (UMIN000008345).

The Concept of Risk Assessment and Being Unfit for Surgery

The concept of risk assessment and the identification of surgical unfitness for vascular intervention is a particularly controversial issue today as the minimally invasive surgical population has increased not only in volume but also in complexity (comorbidity profile) and age, requiring an improved pre-operative selection and definition of high risk. A practical step by step (three steps, two points for each) approach for surgical risk assessment is suggested in this review. As a general rule, the identification of a "high risk" patient for vascular surgery follows a step by step process where the risk is clearly defined, quantified (when too "high"?), and thereby stratified based on the procedure, the patient, and the hospital, with the aid of predictive risk scores. However, there is no standardized, updated, and objective definition for surgical unfitness today. The major gap in the current literature on the definition of high risk in vascular patients explains the lack of sound validated predictive systems and limited generalizability of risk scores in vascular surgery. In addition, the concept of fitness is an evolving tool and many traditional high risk criteria and definitions are no longer valid. Given the preventive purpose of most vascular procedures performed in elderly asymptomatic patients, the decision to pursue or withhold surgery requires realistic estimates not only regarding individual peri-operative mortality, but also life expectancy, healthcare priorities, and the patient's primary goals, such as prolongation of life versus maintenance of independence or symptom relief. The overall "frailty" and geriatric risk burden, such as cognitive, functional, social, and nutritional status, are variables that should be also included in the analyses for stratification of surgical risk in elderly vascular patients.

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.

Long-term outcomes and factors influencing late survival following elective abdominal aortic aneurysm repair: A 24-year experience

Background

Abdominal aortic aneurysms can be either treated by an open abdominal aortic aneurysm repair or an endovascular repair. Comparing clinical predictors of outcomes and those which influence survival rates in the long term is important in determining the choice of treatment offered and the decision-making process with patients.

Aims

To determine the influence of pre-existing clinical predictors and perioperative determinants on late survival of elective open abdominal aortic aneurysm repair and endovascular repair at a tertiary hospital.

Methods

Consecutive patients undergoing elective abdominal aortic aneurysm repair from 1990 to 2013 were included. Data were collected from a prospectively acquired database and death data were gathered from the Queensland state death registry. Pre-existing risks and perioperative factors were assessed independently. Kaplan–Meier and Cox regression modeling were performed.

Results

During the study period, 1340 abdominal aortic aneurysms were repaired electively, of which 982 were open abdominal aortic aneurysm repair. The average age was 72.4 years old and 81.7% were males. The cumulative percentage survival rates for open abdominal aortic aneurysms repair at 5, 10, 15 and 20 years were 79, 49, 31 and 22, respectively. The corresponding 5-, 10- and 15-year survival rates for endovascular repair were not significantly different at 75, 49 and 33%, respectively (P = 0.75). Predictors of reduced survival were advanced age, American Society of Anaesthesiology scores, chronic obstructive pulmonary disease, renal impairment, bifurcated grafts, peripheral vascular disease and congestive heart failure.

Conclusions

Open repair offers a good long-term treatment option for patients with an abdominal aortic aneurysm and in our experience there is no significant difference in late survival between open abdominal aortic aneurysms repair and endovascular repair. Consideration of the factors identified in this study that predict reduced long-term survival for open abdominal aortic aneurysms repair and endovascular repair should be considered when deciding repair of abdominal aortic aneurysm.

Proposed research plan for the derivation of a new Cardiac Risk Index

The Revised Cardiac Risk Index (RCRI) was incorporated into the American College of Cardiology/American Heart Association (ACC/AHA) recommendations for the preoperative evaluation of the cardiac patient for noncardiac surgery. The purpose of this review was to analyze studies on cardiovascular clinical risk prediction that had used the previous "standard best" model, the RCRI, as a comparator. This review aims to determine whether modification of the current risk factors or adoption of other risk factors or other risk indices would improve upon the discrimination of cardiac risk prediction when compared with the RCRI. This is necessary because recent risk prediction models have shown better discrimination for major adverse cardiac events, and the pre-eminence of the RCRI is now in question. There is now a need for a new "best standard" cardiovascular risk prediction model to supersede the RCRI. This is desirable because it would: (1) allow for a global standard of cardiovascular risk assessment; (2) provide a standard comparator in all risk prediction research; (3) result in comparable data collection; and (4) allow for individual patient data meta-analyses. This should lead to continued progress in cardiovascular clinical risk prediction. A review of the current evidence suggests that to improve the preoperative clinical risk stratification for adverse cardiac events, a new risk stratification model be built that maintains the clinical risk factors identified in the RCRI, with the following modifications: (1) additional glomerular filtration rate cut points (as opposed to a single creatinine cut point); (2) age; (3) a history of peripheral vascular disease; (4) functional capacity; and (5) a specific surgical procedural category. One would expect a substantial improvement in the discrimination of the RCRI with this approach. Although most noncardiac surgeries will benefit from a standard "generic" cardiovascular risk prediction model, there are data to suggest that patients with human immunodeficiency virus disease who are undergoing vascular surgery may benefit from specific cardiovascular risk prediction models.

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.

Complex common and internal iliac or aortoiliac aneurysms and current approach: individualised open-endovascular or combined procedures

Objective. Bilateral internal iliac artery aneurysms constitute the utmost configuration of infrarenal aortoiliac disease. We detail characteristic aortoiliac disease patterns and reconstructive techniques we have used, along with a visualized decision-making chart and a short review of the literature. Material and Methods. A retrospective, observational study of twelve clinical cases of patients with aortoiliac disease are described. Two patients had a common iliac artery aneurysm and were managed by the application of inversed stent-grafts; another case was repaired by the insertion of a standard bifurcated stent-graft flared in the right common iliac artery and with an iliac branched device in the left iliac arterial axis. Open approach was used in 5 cases and in 4 cases a combination of aortouniliac stent-grafting with femoral-femoral bypass was applied. Results. Technical success was 100%. One endoleak type Ib in a flared iliac limb was observed and corrected by internal iliac embolism and use of an iliac limb stent-graft extension. We report 100% patency rate during 26.3 months of followup. Conclusion. Individualized techniques for the management of isolated iliac or aortoiliac aneurismal desease with special concern in maintaining internal iliac artery perfusion lead to elimination of perioperative complications and long-term durability and patency rates.

Monitoring and staging abdominal aortic aneurysm disease with pulse wave imaging

The abdominal aortic aneurysm (AAA) is a silent and often deadly vascular disease caused by the localized weakening of the arterial wall. Previous work has indicated that local changes in wall stiffness can be detected with pulse wave imaging (PWI), which is a non-invasive technique for tracking the propagation of pulse waves along the aorta at high spatial and temporal resolutions. The aim of this study was to assess the capability of PWI to monitor and stage AAA progression in a murine model of the disease. ApoE/TIMP-1 knockout mice (N = 18) were given angiotensin II for 30 days via subcutaneously implanted osmotic pumps. The suprarenal sections of the abdominal aortas were imaged every 2-3 d after implantation using a 30-MHz VisualSonics Vevo 770 with 15-μm lateral resolution. Pulse wave propagation was monitored at an effective frame rate of 8 kHz by using retrospective electrocardiogram gating and by performing 1-D cross-correlation on the radiofrequency signals to obtain the displacements induced by the waves. In normal aortas, the pulse waves propagated at constant velocities (2.8 ± 0.9 m/s, r(2) = 0.89 ± 0.11), indicating that the composition of these vessels was relatively homogeneous. In the mice that developed AAAs (N = 10), the wave speeds in the aneurysm sac were 45% lower (1.6 ± 0.6 m/s) and were more variable (r(2) = 0.66 ± 0.23). Moreover, the wave-induced wall displacements were at least 80% lower within the sacs compared with the surrounding vessel. Finally, in mice that developed fissures (N = 5) or ruptures (N = 3) at the sites of their AAA, higher displacements directed out of the lumen and with no discernible wave pattern (r(2) < 0.20) were observed throughout the cardiac cycle. These findings indicate that PWI can be used to distinguish normal murine aortas from aneurysmal, fissured and ruptured ones. Hence, PWI could potentially be used to monitor and stage human aneurysms by providing information complementary to standard B-mode ultrasound.

Glasgow aneurysm scores in patients undergoing open surgical procedure for aortic aneurysm

BACKGROUND

To assess the applicability of the Glasgow aneurysm score (GAS) in patients with aortic aneurysm undergoing an elective open surgical procedure in our hospital.

MATERIALS AND METHODS

A total of 105 patients undergoing elective open surgical procedure between January 2006 and June 2012 were evaluated retrospectively. Glasgow aneurysm score (GAS) was calculated as age+7 points for myocardial disease, +10 points for cerebrovascular disease, and +14 points for renal disease. The best cut-off value for GAS was determined using the ROC curve analysis.

RESULTS

The hospital mortality rate was 3.8% (4 patients). GAS was significantly lower in patients who survived the operation (76.05 ± 14.71 vs. 92.0 ± 10.8 respectively, p = 0.031). The ICU stay was also significantly lower in patients who survived the operation (2.37 ± 5.23) compared to the nonsurvivors (25.67 ± 13.80, p = 0.001). No significant difference was observed regarding age, duration of hospital stay, and aortic diameter. The area under the ROC curve was 0.818 and for a 100% sensitivity rate, the cut-off value for GAS was 77.5 with a 58.4% specificity rate (p = 0.031). All patients with a GAS < 77.5 were alive after surgery.

CONCLUSION

The GAS appears to be a reliable clinical predictor for in hospital mortality following elective repair of abdominal aortic aneurysm following open surgical procedure.

Glasgow aneurysm score in predicting outcome after ruptured abdominal aortic aneurysm

OBJECTIVE

To assess the ability of Glasgow Aneurysm Score in predicting postoperative mortality for ruptured aortic aneurysm which may assist in decision making regarding the open surgical repair of an individual patient.

METHODS

A total of 121 patients diagnosed of ruptured abdominal aortic aneurysm who underwent open surgery in our hospital between 1999 and 2013 were included. The Glasgow Aneurysm Score for each patient was graded according to the Glasgow Aneurysm Score (Glasgow Aneurysm Score = age in years + 17 for shock + 7 for myocardial disease + 10 for cerebrovascular disease + 14 for renal disease). The groups were divided as Group 1 (containing the patients who died) and Group 2 (the patients who were discharged). The Glasgow Aneurysm Scores amongst the groups were compared.

RESULTS

Out of 121 patients, 108 (89.3%) were males and 13 (10.7%) were females. The in-hospital mortality was 48 patients (39.7%). The Glasgow Aneurysm Score was 84.15 ± 15.94 in Group 1 and 75.14 ± 14.67 in Group 2 which revealed significance (p = 0.002). The most appropriate cut-off value for Glasgow Aneurysm Score was determined as 78.5 (AUC = 0.669, p = 0.002, sensitivity: 64.6%, specificity: 60.3%). Glasgow Aneurysm Score value above 78.5 is associated with almost threefold increase in mortality (p = 0.007, OR:2.76, 95% CI 1.30-5.89). In further logistic regression models, Glasgow Aneurysm Score value and preoperative hematocrit values were found to be independent predictors for mortality (p = 0.023 and p = 0.007, respectively).

CONCLUSION

Glasgow Aneurysm Score may have a predictive value for outcome of patients with ruptured abdominal aortic aneurysm undergoing open surgical procedure and it appears to be a useful tool in clinical decision-making of an individual patient when integrated with clinical experience.

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.

Impact of introducing endovascular aneurysm repair on treatment strategy for repair of abdominal aortic aneurysm--National Hospital Organization network study in Japan

BACKGROUND

The objective of the present study was to assess the hypothesis that the introduction of endovascular aneurysm repair (EVAR) into Japan has expanded the indication of abdominal aortic aneurysm (AAA) repair without increasing surgical mortality.

METHODS AND RESULTS

From 10 national hospitals, we registered a total of 2,154 consecutive patients (Open surgery [OS]: n=1,577, EVAR: n=577) over 8 years, divided into 4 time periods: Group I (2005-2006: n=522), Group II (2007-2008: n=475), Group III (2009-2010: n=551), Group IV, (2011-2012: n=606). Mean age increased over the 4 time periods (P<0.0001). The incidences of COPD, smoking history, history of abdominal surgery and concomitant malignancy significantly increased as well, while the numbers of patients with preoperative shock or high ASA status reduced over time. The proportion of EVAR in AAA repair increased from: 0% in Group I, 11.6% in Group II, 41.0% in Group III, to 48.8% in Group IV (P<0.0001). Early mortality was 0.8% in the EVAR and 3.4% in the OS (P<0.001) groups. Survival rates among the 4 groups free of all-cause death and aneurysm-related death at 1 year were 92.1-96.3% (P=0.1555) and 95.5-96.8% (P=0.9891), respectively. Multiple logistic regression analysis for surgical death failed to demonstrate survival advantage of EVAR over OS.

CONCLUSIONS

Introduction of EVAR expanded the indication of AAA repair without increasing mortality, while high risk for anesthesia and emergency cases reduced over time. UMIN-CTR (UMIN000008345).