Characteristics that define high risk in carotid endarterectomy from the Vascular Study Group of New England

Using Machine Learning to Predict Outcomes Following Transfemoral Carotid Artery Stenting

BACKGROUND

Transfemoral carotid artery stenting (TFCAS) carries important perioperative risks. Outcome prediction tools may help guide clinical decision-making but remain limited. We developed machine learning algorithms that predict 1-year stroke or death following TFCAS.

METHODS AND RESULTS

The VQI (Vascular Quality Initiative) database was used to identify patients who underwent TFCAS for carotid artery stenosis between 2005 and 2024. We identified 112 features from the index hospitalization (82 preoperative [demographic/clinical], 13 intraoperative [procedural], and 17 postoperative [in-hospital course/complications]). The primary outcome was 1-year postprocedural stroke or death. The data were divided into training (70%) and test (30%) sets. Six machine learning models were trained using preoperative features with 10-fold cross-validation. The primary model evaluation metric was area under the receiver operating characteristic curve. The algorithm with the best performance was further trained using intra- and postoperative features. Model robustness was assessed using calibration plots and Brier scores. Overall, 35 214 patients underwent TFCAS during the study period and 3257 (9.2%) developed 1-year stroke or death. The best preoperative prediction model was extreme gradient boosting, achieving an area under the receiver operating characteristic curve of 0.94 (95% CI, 0.93-0.95). In comparison, logistic regression had an AUROC of 0.65 (95% CI, 0.63-0.67). The extreme gradient boosting model maintained excellent performance at the intra- and postoperative stages, with area under the receiver operating characteristic curve values of 0.94 (95% CI, 0.93-0.95) and 0.98 (95% CI, 0.97-0.99), respectively. Calibration plots showed good agreement between predicted/observed event probabilities with Brier scores of 0.11 (preoperative), 0.11 (intraoperative), and 0.09 (postoperative).

CONCLUSIONS

Machine learning can accurately predict 1-year stroke or death following TFCAS, performing better than logistic regression.

Systemic immune-inflammation index for predicting poor outcome after carotid endarterectomy: A novel hematological marker

OBJECTIVE

To investigate the predictive role of systemic immune-inflammation index (SII) on postoperative poor outcome in patients undergoing carotid endarterectomy (CEA).

METHODS

A total of 347 patients undergoing elective isolated CEA between March 2010 and April 2022 were included in this multicenter retrospective observational cohort and risk-prediction study and were divided into two groups as poor outcome group (n = 23) and favorable outcome group (n = 324). Poor outcome was defined as the presence of at least one of the complications within 30 days of surgery including stroke, myocardial infarction, and death. The patients' baseline clinical characteristics, comorbidities, and hematological indices were derived from the complete blood count (CBC) analysis, and perioperative data, outcomes, and complications were screened, recorded, and then compared between the groups. Multivariate logistic regression and receiver-operating characteristic (ROC) curve analyses were conducted following univariate analyses to detect the independent predictors of poor outcome as well as the cutoff values with sensitivity and specificity rates.

RESULTS

A total of 23 patients out of 347 (6.6%) manifested poor outcome; and stroke, myocardial infarction, and death occurred in 13, 3, and 7 cases, respectively. There were no significant differences between the groups in terms of basic clinical characteristics, comorbidities, and perioperative data, except for lengths of intensive care unit and hospital stays. Although the median values of PLT, PLR, NLR, and SII of the poor outcome group were found to be significantly higher than the favorable outcome group in univariate analysis, only SII was detected to be a significant and independent predictor of poor outcome in multivariate logistic regression analysis (OR = 1.0008; 95% CI: 1.0004-1.0012; p = 0.002). ROC curve analysis revealed that SII of 1356 × 103/mm3 constituted the cutoff value for predicting poor outcome with 78.3% sensitivity and 64.5% specificity (AUC = 0.746; 95% CI: 0.64-0.851).

CONCLUSIONS

Our study revealed for the first time in the literature that SII significantly predicted poor outcome after CEA.

Predicting Major Adverse Cardiovascular Events Following Carotid Endarterectomy Using Machine Learning

Background Carotid endarterectomy (CEA) is a major vascular operation for stroke prevention that carries significant perioperative risks; however, outcome prediction tools remain limited. The authors developed machine learning algorithms to predict outcomes following CEA. Methods and Results The National Surgical Quality Improvement Program targeted vascular database was used to identify patients who underwent CEA between 2011 and 2021. Input features included 36 preoperative demographic/clinical variables. The primary outcome was 30-day major adverse cardiovascular events (composite of stroke, myocardial infarction, or death). The data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, 6 machine learning models were trained using preoperative features. The primary metric for evaluating model performance was area under the receiver operating characteristic curve. Model robustness was evaluated with calibration plot and Brier score. Overall, 38 853 patients underwent CEA during the study period. Thirty-day major adverse cardiovascular events occurred in 1683 (4.3%) patients. The best performing prediction model was XGBoost, achieving an area under the receiver operating characteristic curve of 0.91 (95% CI, 0.90-0.92). In comparison, logistic regression had an area under the receiver operating characteristic curve of 0.62 (95% CI, 0.60-0.64), and existing tools in the literature demonstrate area under the receiver operating characteristic curve values ranging from 0.58 to 0.74. The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.02. The strongest predictive feature in our algorithm was carotid symptom status. Conclusions The machine learning models accurately predicted 30-day outcomes following CEA using preoperative data and performed better than existing tools. They have potential for important utility in guiding risk-mitigation strategies to improve outcomes for patients being considered for CEA.

Strategy of carotid artery stenting as first-line treatment and carotid endarterectomy for carotid artery stenosis: A single-center experience

Background:

The main surgical options for stenosis of the carotid artery are carotid endarterectomy (CEA) and carotid artery stenting (CAS). The number of CAS procedures performed in Japan greatly exceeds that of CEA procedures. In this study, we used data from a single center to examine CAS and CEA for carotid artery stenosis.

Methods:

The subjects were patients with carotid artery stenosis who underwent CAS or CEA between January 2012 and May 2020. CAS was the first-choice treatment. CEA was used in cases with vulnerable plaques, a relatively low risk of general anesthesia, and no anatomical features disadvantageous for endarterectomy.

Results:

A total of 140 cases (102 CAS and 38 CEA) were examined. There were more elderly patients in the CAS group. The CEA group had a higher rate of vulnerable plaques and only one case with an unfavorable anatomy for CEA. Major adverse events (stroke) occurred in two CAS cases. In multivariate logistic analysis, postoperative ischemic lesions were independently associated with age (odds ratio [OR] = 1.13, 95% confidence interval [CI]: 1.01–1.26, P = 0.026) and vulnerable plaque (OR = 5.54, 95% CI: 1.48–20.70, P = 0.011) in the CAS group, but not in the CEA group.

Conclusion:

The results reflect the treatment algorithm at our hospital, indicating that triage is accurate. Thus, it is beneficial to assign cases based primarily on plaque vulnerability and anatomical risk for CEA, and to not hesitate to perform CEA simply because of old age. CAS as first-line treatment and CEA are effective and safe, which reflect the treatment situation in Japan.

External Validation of Risk Prediction Models to Improve Selection of Patients for Carotid Endarterectomy

BACKGROUND AND PURPOSE

The net benefit of carotid endarterectomy (CEA) is determined partly by the risk of procedural stroke or death. Current guidelines recommend CEA if 30-day risks are <6% for symptomatic stenosis and <3% for asymptomatic stenosis. We aimed to identify prediction models for procedural stroke or death after CEA and to externally validate these models in a large registry of patients from the United States.

METHODS

We conducted a systematic search in MEDLINE and EMBASE for prediction models of procedural outcomes after CEA. We validated these models with data from patients who underwent CEA in the American College of Surgeons National Surgical Quality Improvement Program (2011-2017). We assessed discrimination using C statistics and calibration graphically. We determined the number of patients with predicted risks that exceeded recommended thresholds of procedural risks to perform CEA.

RESULTS

After screening 788 reports, 15 studies describing 17 prediction models were included. Nine were developed in populations including both asymptomatic and symptomatic patients, 2 in symptomatic and 5 in asymptomatic populations. In the external validation cohort of 26 293 patients who underwent CEA, 702 (2.7%) developed a stroke or died within 30-days. C statistics varied between 0.52 and 0.64 using all patients, between 0.51 and 0.59 using symptomatic patients, and between 0.49 to 0.58 using asymptomatic patients. The Ontario Carotid Endarterectomy Registry model that included symptomatic status, diabetes, heart failure, and contralateral occlusion as predictors, had C statistic of 0.64 and the best concordance between predicted and observed risks. This model identified 4.5% of symptomatic and 2.1% of asymptomatic patients with procedural risks that exceeded recommended thresholds.

CONCLUSIONS

Of the 17 externally validated prediction models, the Ontario Carotid Endarterectomy Registry risk model had most reliable predictions of procedural stroke or death after CEA and can inform patients about procedural hazards and help focus CEA toward patients who would benefit most from it.

Understanding the Role and Value of Process Quality Indicators in Older Vascular Surgery Inpatients

BACKGROUND

Despite the development of geriatrics surgery process quality indicators (QIs), few studies have reported on these QIs in routine surgical practice. Even less is known about the links between these QIs and clinical outcomes, and patient characteristics. We aimed to measure geriatrics surgery process QIs, and investigate the association between process QIs and outcomes, and QIs and patient characteristics, in hospitalized older vascular surgery patients.

METHODS

This was a prospective cohort study of 150 consecutive patients aged ≥ 65 years admitted to a tertiary vascular surgery unit. Occurrence of geriatrics surgery process QIs as part of routine vascular surgery care was measured. Associations between QIs and high-risk patient characteristics, and QIs and clinical outcomes were assessed using clustered heatmaps.

RESULTS

QI occurrence rate varied substantially from 2% to 93%. Some QIs, such as cognition and delirium screening, documented treatment preferences, and geriatrician consultation were infrequent and clustered with high-risk patient characteristcs. There were two major process-outcome clusters: (a) multidisciplinary consultations, communication and screening-based process QIs with multiple adverse outcomes, and (b) documentation and prescribing-related QIs with fewer adverse outcomes.

CONCLUSIONS

Clustering patterns of process QIs with clinical outcomes are complex, and there is a differential occurrence of QIs by patient characteristics. Prospective intervention studies that report on implemented QIs, outcomes and patient characteristics are needed to better understand the causal pathways between process QIs and outcomes, and to help prioritize targets for quality improvement in the care of older surgical patients.

Ipsilateral carotid bypass outcomes in hostile neck anatomy

OBJECTIVE

To determine differences in outcomes among patients undergoing ipsilateral carotid bypass with hostile or normal neck anatomy.

METHODS

Single-center retrospective review of all ipsilateral extracranial carotid bypasses performed between 1998 and 2018.

RESULTS

Forty-eight patients underwent ipsilateral carotid bypass from the common carotid artery to either the internal carotid artery or carotid bifurcation during the study period. Seven patients were excluded owing to either a lack of follow-up or missing data. The indications for intervention included infected patches, aneurysmal degeneration, symptomatic and asymptomatic stenosis or restenosis, carotid body tumors, neck malignancy, and trauma. In 25 procedures (61%), there was a hostile neck anatomy defined as a prior history of external beam neck irradiation or neck surgery. Among this group, 12 pectoralis muscle flaps were performed for reconstructive coverage. Conduits included polytetrafluorethylene (n = 21), great saphenous vein (n = 9), superficial femoral artery (n = 7) and arterial homograft (n = 4). All superficial femoral artery conduits were used in the hostile neck group (P = .03). The overall mean time of follow-up was 22 months, with all bypasses remaining patent with no significant clinical stenosis. The 30-day ipsilateral stroke and myocardial infarction rates were 4.88% each, all within the hostile neck group, with no 30-day mortalities for the entire cohort. One-third of the muscle flaps were performed in the setting of infected patches (P = .02) with no significant differences in perioperative outcomes with use. The overall median hospital length of stay was significantly increased in patients receiving muscle flap coverage (3.0 vs 7.0 days; P = .04).

CONCLUSIONS

In patients with a complex carotid pathology, ipsilateral carotid bypass is an effective solution for carotid reconstruction. Different conduits should be used depending on the indication. Muscle flap coverage should be considered in hostile settings when primary wound closure is not feasible.

Risk Factors of Cerebral Infarction and Myocardial Infarction after Carotid Endarterectomy Analyzed by Machine Learning

Objective

The incidence of cerebral infarction and myocardial infarction is higher in patients with carotid endarterectomy (CEA). Based on the concept of coprotection of heart and brain, this study attempts to screen the related factors of early cerebral infarction and myocardial infarction after CEA with the method of machine learning to provide clinical data for the prevention of postoperative cerebral infarction and myocardial infarction.

Methods

443 patients who received CEA operation under general anesthesia within 2 years were collected as the research objects. The demographic data, previous medical history, degree of neck vascular stenosis, blood pressure at all time points during the perioperative period, the time of occlusion, whether to place the shunt, and the time of hospital stay, whether to have cerebral infarction and myocardial infarction were collected. The machine learning model was established, and stable variables were selected based on single-factor analysis.

Results

The incidence of cerebral infarction was 1.4% (6/443) and that of myocardial infarction was 2.3% (10/443). The hospitalization time of patients with cerebral infarction and myocardial infarction was longer than that of the control group (8 (7, 15) days vs. 7 (5, 8) days, P = 0.002). The stable related factors were screened out by the xgboost model. The importance score (F score) was as follows: average arterial pressure during occlusion was 222 points, body mass index was 159 points, average arterial pressure postoperation was 156 points, the standard deviation of systolic pressure during occlusion was 153 points, diastolic pressure during occlusion was 146 points, mean arterial pressure after entry was 143 points, systolic pressure during occlusion was 121 points, and age was 117 points.

Conclusion

Eight factors, such as blood pressure, body mass index, and age, may be related to the postoperative cerebral infarction and myocardial infarction in patients with CEA. The machine learning method deserves further study.

Learning curve and proficiency of transcarotid artery revascularization compared to transfemoral carotid artery stenting

Both transfemoral carotid artery stenting (TF-CAS) and transcarotid artery revascularization (TCAR) are competing endovascular alternatives to carotid endarterectomy for the treatment of atherosclerotic carotid artery stenosis. TF-CAS is an endovascular procedure associated with a long learning curve and higher periprocedural stroke and death rates during an operator's early experience. Estimates suggest that more than 50 cases are required to achieve outcomes similar to carotid endarterectomy. TCAR is a novel hybrid procedure combining direct common carotid artery access and cerebral blood flow reversal with carotid stent placement. In distinction from TF-CAS, TCAR has a rather short learning curve. A multi-institutional analysis showed that operators achieved technical proficiency after approximately 10 to 15 cases. This was reinforced by a large Society for Vascular Surgery, Vascular Quality Initiative Transcarotid Artery Revascularization Surveillance Project analysis that demonstrated that expertise peaked after approximately 20 cases. Both studies found that TCAR was not associated with an increased rate of stroke or death during operator's early experience. These data suggest that TCAR is readily learned and patients are not at increased risk during a surgeon's early experience.

The Role of Carotid Stump Pressure in Carotid Endarterectomy: A Systematic Review and Meta-Analysis

This review evaluates the carotid stump pressure (CSP)’s role as a single parameter at any given pressure as an indicator for selective shunting, or vice versa, in carotid endarterectomy (CEA). A systematic review of literature in MEDLINE and the Cochrane Library from 1969 to 2019 was conducted. The primary end point was set at 0 to 30-day mortality, ischemic stroke (IS), transient ischemic attack (TIA), and a secondary point at recognition of an optimal CSP pressure. The data was subjected to meta-analytics. The odds ratio (OR) was reported at 95% confidence interval (CI). This study has been registered with PROSPERO: CRD42019119851. The pooled analysis on the primary endpoint of IS demonstrated higher incidence of stroke in shunted CEAs solely based on CSP measurement alone (OR, 0.14, 95%CI: 0.08–0.24, I²=48%, p<0.001). Sub group analysis demonstrated similar patterns at 25 mmHg (OR, 0.06, 95%CI: 0.01–0.5, p<0.01), 30 mmHg (OR, 0.07, 95%CI: 0.01–0.63, p=0.02) and 40 mmHg (OR, 0.23, 95%CI: 0.09–0.57, p<0.01). This effect on end points of mortality and TIA demonstrated no benefit in either direction. CSP, as a single criterion, is not a reliable parameter in reduction of TIA, mortality, and IS at any given pressure range.

A Multilevel Analysis of Surgical Category and Individual Patient-Level Risk Factors for Postoperative Stroke

Background and Purpose

Many studies supporting the association between specific surgical procedure categories and postoperative stroke (POS) do not account for differences in patient-level characteristics between and within surgical categories. The risk of POS after high-risk procedure categories remains unknown after adjusting for such differences in patient-level characteristics.

Methods

Using inpatients in the American College of Surgeons National Surgical Quality Initiative Program database, we conducted a retrospective cohort study between January 1, 2000, and December 31, 2010. Our primary outcome was POS within 30 days of surgery. We characterized the relationship between surgical- and individual patient-level factors and POS by using multivariable, multilevel logistic regression that accounted for clustering of patient-level factors with surgical categories.

Results

We identified 729 886 patients, 2703 (0.3%) of whom developed POS. Dependent functional status (odds ratio [OR]: 4.11, 95% confidence interval [95% CI]: 3.60-4.69), history of stroke (OR: 2.35, 95%CI: 2.06-2.69) or transient ischemic attack (OR: 2.49 95%CI: 2.19-2.83), active smoking (OR: 1.20, 95%CI: 1.08-1.32), hypertension (OR: 2.11, 95%CI: 2.19-2.82), chronic obstructive pulmonary disease (OR: 1.39 95%CI: 1.21-1.59), and acute renal failure (OR: 2.35, 95%CI: 1.85-2.99) were significantly associated with POS. After adjusting for clustering, patients who underwent cardiac (OR: 11.25, 95%CI: 8.52-14.87), vascular (OR: 4.75, 95%CI: 3.88-5.82), neurological (OR: 4.60, 95%CI: 3.48-6.08), and general surgery (OR: 1.40, 95%CI: 1.15-1.70) had significantly greater odds of POS compared to patients undergoing other types of surgical procedures.

Conclusions

Vascular, cardiac, and neurological surgery remained strongly associated with POS in an analysis accounting for the association between patient-level factors and surgical categories.

External validation of the Vascular Study Group of New England carotid endarterectomy risk predictive model using an independent U.S. national surgical database

OBJECTIVE

Previously, we described a Vascular Study Group of New England (VSGNE) risk predictive model to predict composite adverse outcomes (postoperative death, stroke, myocardial infarction, or discharge to extended care facilities) after carotid endarterectomy (CEA). The goal of this study was to externally validate this model using an independent database.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) CEA-targeted database (2010-2014) was used to externally validate the risk predictor model of adverse outcomes after CEA previously created using the VSGNE carotid database. Emergent cases and those in which CEA was combined with another operation were excluded. Cases in which a discharge destination cannot be determined were also excluded. To assess the predictive power of our VSGNE prediction score within this sample, a receiver operating characteristic curve was constructed. Risk scores for each NSQIP patient were also computed using beta weights from the VSGNE CEA model. To further assess the construct validity of our VSGNE prediction score, the observed proportion of adverse outcomes was examined at each level of our prediction scale and within five roughly equally sized risk groups formed on the basis of our VSGNE prediction scores.

RESULTS

In this database, 10,889 cases met our inclusion criteria and were used in this analysis. The overall rate of adverse outcomes in this cohort was 8.5%. External validation of the VSGNE model on this sample showed moderately good predictive ability (area under the curve = 0.745). Patients in progressively higher risk groups, based on their VSGNE model scores, exhibited progressively higher rates of observed adverse outcomes, as predicted.

CONCLUSIONS

The VSGNE CEA risk predictive model was externally validated on an NSQIP CEA-targeted sample and showed a fairly accurate global predictive ability for adverse outcomes after CEA. Although this model has a good population concordance, the lack of cut point indicates that individual risk prediction requires more evaluation. Further studies should be geared toward identification of variables that make this risk predictive model more robust.

[Some comments on the 2017 European Guidelines on treatment of atherosclerotic lesions of brachiocephalic arteries]

Analysed herein are the indications for primary interventions in patients with atherosclerotic lesions of internal carotid arteries according to the recommendations laid down in the 2017 Guidelines of the European Society for Vascular Surgery.

[Multimorbid vascular patients-do endovascular techniques expand the limits?]

The answer to the question of whether endovascular techniques extend the barriers to treatment in multimorbid vascular patients depends on the localization of the vascular disease and its stage. In multimorbid vascular patients with limited life expectancy and asymptomatic carotid stenosis, neither an endovascular nor an open procedure is indicated but a conservative best medicinal treatment is to be preferred. In symptomatic carotid stenosis the endovascular procedure is indicated for special anatomical conditions, such as contralateral carotid artery occlusion, contralateral recurrent nerve palsy, recurrent stenosis following endarterectomy, radical neck dissection and radiotherapy in the cervical region. In the treatment of intact abdominal aortic aneurysms (AAA), endovascular procedures reduce the perioperative risk especially in older patients, allowing the indications for intervention in this group of patients to be expanded, provided that the life expectancy of such treated patients is still several years. There is no clear evidence as to whether endovascular repair should be preferred in ruptured AAAs but there are indications that with the establishment of EVAR the proportion of patients receiving treatment has increased in those patients who were previously denied surgery after arrival in hospital. In critical limb ischemia the propagation of endovascular techniques has not so much extended the indications for invasive therapy but instead the endovascular approach has superseded open bypass surgery, which is positively reflected in a lower perioperative morbidity, especially in older frail patients.

Impact of diabetes mellitus on early outcome of carotid endarterectomy

BACKGROUND

Diabetes mellitus increases the risk of ischaemic stroke in the general population but its impact on early outcome after the carotid endarterectomy (CEA) is controversial with conflicting results.

PATIENTS AND METHODS

This prospective study includes 902 consecutive CEAs. Patients were divided into non-diabetic and diabetic groups and subsequently analysed. Early outcomes in terms of 30-day stroke and death rates were then analysed and compared.

RESULTS

There were 606 non-diabetic patients. Among 296 diabetic patients, 83 were insulin-dependent. The cumulative TIA/stroke rate was statistically higher in the diabetic group (2.6 vs. 5.7 %, P = 0.02). Stroke was more frequent in the diabetic group (2.0 vs. 4.4 %, P = 0.04) comparedto TIA (0.7 vs. 1.4 %, P = 0.45). Mortality was statistically more frequent in diabetic patients (0.2 vs. 1.7 %, P = 0.01). The 30-day stroke/death rate (2.6 vs. 5.7 %, P = 0.02) was also statistically higher in the diabetic group. Factors that were identified to increase risk of death and stroke in multivariate analysis were: use of insulin for blood glucose control (OR = 2.47, 95 % CI 1.61-4.68, P = 0.01), higher low-density lipoprotein cholesterol value (OR = 1.52, 95 % CI 1.15-2.22, P < 0.01), presence of coronary disease (OR = 2.04, 95 % CI 1.40-3.31, P = 0.03), peripheral artery disease (OR = 2.14, 95 % CI 1.34-3.65, P = 0.02), complicated plaque (OR = 1.77, 95 % CI 1.11-3.68, P = 0.03), contralateral carotid artery occlusion (OR = 2.37, 95 % CI 1.25-4.74, P = 0.02), shunt use (OR = 3.46, 95 % CI 1.18-7.10, P < 0.01), and among diabetic patients higher HbA1c levels (OR = 1.28, 95 % CI 1.05-1.66, P = 0.03). Clamp toleration was associated with lower risk of death and stroke rates (OR = 0.43, 95 % CI 0.23-0.76, P < 0.01).

CONCLUSIONS

In our study, perioperative neurological complications and mortality were statistically higher in diabetic patients compared to non-diabetic patients during CEA. Further research will have to show whether other treatment modalities of carotid artery stenosis and better glycaemia and dyslipidaemia controlling in diabetics can reduce this risk.

Carotid Artery Stent Placement and Carotid Endarterectomy: A Challenge for Urgent Treatment after Stroke-Early and 12-Month Outcomes in a Comprehensive Stroke Center

PURPOSE

To compare feasibility, 12-month outcome, and periprocedural and postprocedural risks between carotid artery stent (CAS) placement and carotid endarterectomy (CEA) performed within 1 week after transient ischemic attack (TIA) or mild to severe stroke onset in a single comprehensive stroke center.

MATERIALS AND METHODS

Retrospective analysis of prospective data collected from 1,148 patients with ischemic stroke admitted to a single stroke unit between January 2013 and July 2015 was conducted. Among 130 consecutive patients with symptomatic carotid stenosis, 110 (10 with TIA, 100 with stroke) with a National Institutes of Health Stroke Scale (NIHSS) score < 20 and a prestroke modified Rankin Scale (mRS) score < 2 were eligible for CAS placement or CEA and treated according to the preference of the patient or a surrogate. Periprocedural (< 48 h) and postprocedural complications, functional outcome, stroke, and death rate up to 12 months were analyzed.

RESULTS

Sixty-two patients were treated with CAS placement and 48 were treated with CEA. Several patients presented with moderate or major stroke (45.8% CEA, 64.5% CAS). NIHSS scores indicated slightly greater severity at onset in patients treated with a CAS vs CEA (6.6 ± 5.7 vs 4.2 ± 3.4; P = .08). Complication rates were similar between groups. mRS scores showed a significant improvement over time and a significant interaction with age in both groups. Similar incidences of death or stroke were shown on survival analysis. A subanalysis in patients with NIHSS scores ≥ 4 showed no differences in complication rate and outcome.

CONCLUSIONS

CAS placement and CEA seem to offer early safe and feasible secondary stroke prevention treatments in experienced centers, even after major atherosclerotic stroke.

Quality and Safety in Health Care, Part XXIV: More on Vascular Surgery

The use of registries such as the Vascular Quality Initiative and its regional groups, such as the Vascular Study Group of New England, have been very helpful in investigating problems related to quality and safety in vascular surgery. This article discusses some of their contributions regarding carotid artery procedures, the use of certain medications in the perioperative period, and the risk factors for sustaining a major cardiac complication while in the hospital after vascular surgery.

The Role of the Model of End-Stage Liver Disease Score in Predicting Outcomes of Carotid Endarterectomy

Objectives:

The Model of End-Stage Liver Disease (MELD) score has been traditionally utilized to prioritize for liver transplantation; however, recent literature has shown its value in predicting surgical outcomes for patients with hepatic dysfunction. The benefit of carotid endarterectomy in asymptomatic patients is dependent on low perioperative morbidity. Our objective was to use MELD score to predict outcomes in asymptomatic patients undergoing carotid endarterectomy.

Methods:

Patients undergoing carotid endarterectomy were identified in the National Surgical Quality Improvement Program data sets from 2005 to 2012. The Model of End-Stage Liver Disease score was calculated using serum bilirubin, creatinine, and the international normalized ratio (INR). Patients were grouped into low (<9), moderate (9-14), and high (15+) MELD classifications. The effect of the MELD score on postoperative morbidity and mortality was assessed by multivariable logistic and gamma regressions and propensity matching.

Results:

There were 7966 patients with asymptomatic carotid endarterectomy identified. The majority 5556 (70%) had a low MELD score, 1952 (25%) had a moderate MELD score, and 458 (5%) had a high MELD score. High MELD score was independently predictive of postoperative death, increased length of stay, need for transfusion, pulmonary complications, and a statistical trend toward increased cardiac arrest/myocardial infarction. The Model of End-Stage Liver Disease score did not affect postoperative stroke, wound complications, or operative time.

Conclusion:

High MELD score places asymptomatic patients undergoing carotid endarterectomy at a higher risk of adverse outcomes in the 30 days following surgery. This provides further empirical evidence for risk stratification when considering treatment for these patients. Outcomes of medical management or carotid stenting should be investigated in high-risk patients.

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.