The Comprehensive Risk Assessment for Bypass (CRAB) facilitates efficient perioperative risk assessment for patients with critical limb ischemia

How multidisciplinary clinics may mitigate socioeconomic barriers to care for chronic limb-threatening ischemia

OBJECTIVE

Although multidisciplinary clinics improve outcomes in chronic limb-threatening ischemia (CLTI), their role in addressing socioeconomic disparities is unknown. Our institution treats patients with CLTI at both traditional general vascular clinics and a multidisciplinary Limb Preservation Program (LPP). The LPP is in a minority community, providing expedited care at a single facility by a consistent team. We compared outcomes within the LPP with our institution's traditional clinics and explored patients' perspectives on barriers to care to evaluate if the LPP might address them.

METHODS

All patients undergoing index revascularization for CLTI from 2014 to 2023 at our institution were stratified by clinic type (LPP or traditional). We collected clinical and socioeconomic variables, including Area Deprivation Index (ADI). Patient characteristics were compared using χ2, Student t, or Mood median tests. Outcomes were compared using log-rank and multivariable Cox analysis. We also conducted semi-structured interviews to understand patient-perceived barriers.

RESULTS

From 2014 to 2023, 983 limbs from 871 patients were revascularized; 19.5% of limbs were treated within the LPP. Compared with traditional clinic patients, more LPP patients were non-White (43.75% vs 27.43%; P < .0001), diabetic (82.29% vs 61.19%; P < .0001), dialysis-dependent (29.17% vs 13.40%; P < .0001), had ADI in the most deprived decile (29.38% vs 19.54%; P = .0061), resided closer to clinic (median 6.73 vs 28.84 miles; P = .0120), and had worse Wound, Ischemia, and foot Infection (WIfI) stage (P < .001). There were no differences in freedom from death, major adverse limb event (MALE), or patency loss. Within the most deprived subgroup (ADI >90), traditional clinic patients had earlier patency loss (P = .0108) compared with LPP patients. Multivariable analysis of the entire cohort demonstrated that increasing age, heart failure, dialysis, chronic obstructive pulmonary disease, and increasing WIfI stage were independently associated with earlier death, and male sex was associated with earlier MALE. Ten traditional clinic patients were interviewed via convenience sampling. Emerging themes included difficulty understanding their disease, high visit frequency, transportation barriers, distrust of the health care system, and patient-physician racial discordance.

CONCLUSIONS

LPP patients had worse comorbidities and socioeconomic deprivation yet had similar outcomes to healthier, less deprived non-LPP patients. The multidisciplinary clinic's structure addresses several patient-perceived barriers. Its proximity to disadvantaged patients and ability to conduct multiple appointments at a single visit may address transportation and visit frequency barriers, and the consistent team may facilitate patient education and improve trust. Including these elements in a multidisciplinary clinic and locating it in an area of need may mitigate some negative impacts of socioeconomic deprivation on CLTI outcomes.

Anatomical and clinical factors associated with infrapopliteal arterial bypass outcomes in patients with chronic limb-threatening ischemia

The aim of this study was to identify anatomical and clinical factors associated with limb-based patency (LBP) loss, major adverse limb events (MALEs), and poor amputation-free survival (AFS) after an infrapopliteal arterial bypass (IAB) surgery according to the Global Limb Anatomic Staging System. A retrospective analysis of patients undergoing IAB surgery between January 2010 and December 2021 at a single institution was performed. Two-year AFS, freedom from LBP loss, and freedom from MALEs were assessed using the Kaplan-Meier method. Anatomical and clinical predictors were assessed using multivariate analysis. The total number of risk factors was used to calculate risk scores for subsequent categorization into low-, moderate-, and high-risk groups. IABs were performed on 103 patients. The rates of two-year freedom from LBP loss, freedom from MALEs, and AFS were 71.3%, 76.1%, and 77.0%, respectively. The multivariate analysis showed that poor run-off beyond the ankle and a bypass vein caliber of < 3 mm were significantly associated with LBP loss and MALEs. Moreover, end-stage renal disease, non-ambulatory status, and a body mass index of < 18.5 were significantly associated with poor AFS. The rates of freedom from LBP loss and MALEs and the AFS rate were significantly lower in the high-risk group than in the other two groups (12-month low-risk rates: 92.2%, 94.8%, and 94.4%, respectively; 12-month moderate-risk rates: 58.6%, 84.6%, and 78.3%, respectively; 12-month high-risk rates: 11.1%, 17.6%, and 56.2%, respectively; p < 0.001, p < 0.001, and p < 0.001, respectively). IAB is associated with poor clinical outcomes in terms of LBP, MALEs, and AFS in high-risk patients. Risk stratification based on these predictors is useful for long-term prognosis.

Artificial Intelligence of Arterial Doppler Waveforms to Predict Major Adverse Outcomes Among Patients Evaluated for Peripheral Artery Disease

BACKGROUND

Patients with peripheral artery disease are at increased risk for major adverse cardiac events, major adverse limb events, and all-cause death. Developing tools capable of identifying those patients with peripheral artery disease at greatest risk for major adverse events is the first step for outcome prevention. This study aimed to determine whether computer-assisted analysis of a resting Doppler waveform using deep neural networks can accurately identify patients with peripheral artery disease at greatest risk for adverse outcome events.

METHODS AND RESULTS

Consecutive patients (April 1, 2015, to December 31, 2020) undergoing ankle-brachial index testing were included. Patients were randomly allocated to training, validation, and testing subsets (60%/20%/20%). Deep neural networks were trained on resting posterior tibial arterial Doppler waveforms to predict major adverse cardiac events, major adverse limb events, and all-cause death at 5 years. Patients were then analyzed in groups based on the quartiles of each prediction score in the training set. Among 11 384 total patients, 10 437 patients met study inclusion criteria (mean age, 65.8±14.8 years; 40.6% women). The test subset included 2084 patients. During 5 years of follow-up, there were 447 deaths, 585 major adverse cardiac events, and 161 MALE events. After adjusting for age, sex, and Charlson comorbidity index, deep neural network analysis of the posterior tibial artery waveform provided independent prediction of death (hazard ratio [HR], 2.44 [95% CI, 1.78-3.34]), major adverse cardiac events (HR, 1.97 [95% CI, 1.49-2.61]), and major adverse limb events (HR, 11.03 [95% CI, 5.43-22.39]) at 5 years.

CONCLUSIONS

An artificial intelligence-enabled analysis of Doppler arterial waveforms enables identification of major adverse outcomes among patients with peripheral artery disease, which may promote early adoption and adherence of risk factor modification.

Peak Aortic Valve Jet Velocity is an Independent Predictor of Mortality of Dialysis Patients Undergoing Open Surgery for Chronic Limb Threatening Ischemia

BACKGROUND

To investigate the impact of peak aortic jet velocity (Vmax) on the prognosis of patients undergoing open surgery for chronic limb threatening ischemia (CLTI).

METHODS

Between April 2015 and March 2022, 352 patients underwent infrainguinal open surgery for CLTI. Patients who met the following exclusion criteria were excluded: subsequent infrainguinal surgeries in the registered period, no record of Vmax, history of aortic valve intervention, and Vmax ≥3.0 m/s (moderate or severe aortic valve stenosis). The remaining patients were dichotomized into 2 groups based on their Vmax values. The Youden index calculated from the receiver operating characteristic curve (ROC) was set as the cutoff value. The 2-year overall survival (OS), calculated using the Kaplan-Meier's method, was compared between the 2 groups. A Cox proportional hazards regression analysis was performed using perioperative factors including Vmax to identify independent predictors separately for dialysis and nondialysis patients and the quantitative relationship between Vmax and OS.

RESULTS

One hundred and ninety-one patients, including 100 dialysis and 91 nondialysis patients, were included in the analysis. The Youden index was 1.7 m/s. The 2-year OS rates of the group with Vmax >1.7 m/s and with Vmax ≤1.7 m/s were 49% and 76% (P = 0.007), respectively, in the dialysis cohort, while they were 71% and 78% (P = 0.680) in the nondialysis cohort, respectively. Multivariate analysis identified Vmax and ejection fraction as independent predictors in the dialysis cohort and the Barthel Index at admission in the nondialysis cohort. There was a stepwise increase in the risk of death in patients with Vmax of ≥1.5 m/s and a significantly higher risk of death in dialysis patients with Vmax >2.5 m/s.

CONCLUSIONS

Vmax was a significant independent predictor of all-cause death within 2 years after open surgery for CLTI in dialysis patients but not in patients managed without dialysis.

Comparison of lower extremity bypass and peripheral vascular intervention for chronic limb-threatening ischemia in the Medicare-linked Vascular Quality Initiative

OBJECTIVE

There is a relative lack of comparative effectiveness research on revascularization for patients with chronic limb-threatening ischemia (CLTI). We examined the association between lower extremity bypass (LEB) vs peripheral vascular intervention (PVI) for CLTI and 30-day and 5-year all-cause mortality and 30-day and 5-year amputation.

METHODS

Patients undergoing LEB and PVI of the below-the-knee popliteal and infrapopliteal arteries between 2014 and 2019 were queried from the Vascular Quality Initiative, and outcomes data were obtained from the Medicare claims-linked Vascular Implant Surveillance and Interventional Outcomes Network database. Propensity scores were calculated on 15 variables using a logistic regression model to control for imbalances between treatment groups. A 1:1 matching method was used. Kaplan-Meier survival curves and hierarchical Cox proportional hazards regression with a random intercept for site and operator nested in site to account for clustered data compared 30-day and 5-year all-cause mortality between groups. Thirty-day and 5-year amputation were subsequently compared using competing risk analysis to account for the competing risk of death.

RESULTS

There was a total of 2075 patients in each group. The overall mean age was 71 ± 11 years, 69% were male, and 76% were white, 18% were black, and 6% were of Hispanic ethnicity. Baseline clinical and demographic characteristics in the matched cohort were balanced between groups. There was no association between all-cause mortality over 30 days and LEB vs PVI (cumulative incidence, 2.3% vs 2.3% by Kaplan Meier; log-rank P-value = .906; hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.62-1.44; P-value = .80). All-cause mortality over 5 years was lower for LEB vs PVI (cumulative incidence, 55.9% vs 60.1% by Kaplan Meier; log-rank P-value < .001; HR, 0.77; 95% CI, 0.70-0.86; P-value < .001). Accounting for competing risk of death, amputation over 30 days was also lower in LEB vs PVI (cumulative incidence function, 1.9% vs 3.0%; Fine and Gray P-value = .025; subHR, 0.63; 95% CI, 0.42-0.95; P-value = .025). There was no association between amputation over 5 years and LEB vs PVI (cumulative incidence function, 22.6% vs 23.4%; Fine and Gray P-value = .184; subHR, 0.91; 95% CI, 0.79-1.05; P-value = .184).

CONCLUSIONS

In the Vascular Quality Initiative-linked Medicare registry, LEB vs PVI for CLTI was associated with a lower risk of 30-day amputation and 5-year all-cause mortality. These results will serve as a foundation to validate recently published randomized controlled trial data, and to broaden the comparative effectiveness evidence base for CLTI.

Application of machine learning algorithms in electronic medical records to predict amputation-free survival after first revascularization in patients with peripheral artery disease

BACKGROUND

This study aimed to apply eight machine learning algorithms to develop the optimal model to predict amputation-free survival (AFS) after first revascularization in patients with peripheral artery disease (PAD).

METHODS

Among 2130 patients from 2011 to 2020, 1260 patients who underwent revascularization were randomly assigned to training set and validation set in an 8:2 ratio. 67 clinical parameters were analyzed by lasso regression analysis. Logistic regression, gradient boosting machine, random forest, decision tree, eXtreme gradient boosting, neural network, Cox regression, and random survival forest (RSF) were applied to develop prediction models. The optimal model was compared with GermanVasc score in testing set comprising patients from 2010.

RESULTS

The postoperative 1/3/5-year AFS were 90%, 79.4%, and 74.1%. Age (HR:1.035, 95%CI: 1.015-1.056), atrial fibrillation (HR:2.257, 95%CI: 1.193-4.271), cardiac ejection fraction (HR:0.064, 95%CI: 0.009-0.413), Rutherford grade ≥ 5 (HR:1.899, 95%CI: 1.296-2.782), creatinine (HR:1.03, 95%CI: 1.02-1.04), surgery duration (HR:1.03, 95%CI: 1.01-1.05), and fibrinogen (HR:1.292, 95%CI: 1.098-1.521) were independent risk factors. The optimal model was developed by RSF algorithm, with 1/3/5-year AUCs in training set of 0.866 (95% CI:0.819-0.912), 0.854 (95% CI:0.811-0.896), 0.844 (95% CI:0.793-0.894), in validation set of 0.741 (95% CI:0.580-0.902), 0.768 (95% CI:0.654-0.882), 0.836 (95% CI:0.719-0.953), and in testing set of 0.821 (95%CI: 0.711-0.931), 0.802 (95%CI: 0.684-0.919), 0.798 (95%CI: 0.657-0.939). The c-index of the model outperformed GermanVasc Score (0.788 vs 0.730). A dynamic nomogram was published on shinyapp (https://wyy2023.shinyapps.io/amputation/).

CONCLUSION

The optimal prediction model for AFS after first revascularization in patients with PAD was developed by RSF algorithm, which exhibited outstanding prediction performance.

Prediction Models for Two Year Overall Survival and Amputation Free Survival After Revascularisation for Chronic Limb Threatening Ischaemia

OBJECTIVE

The aim of this study was to create prediction models for two year overall survival (OS) and amputation free survival (AFS) after revascularisation in patients with chronic limb threatening ischaemia (CLTI).

METHODS

This was a retrospective analysis of prospectively collected multicentre registry data (JAPAN Critical Limb Ischaemia Database; JCLIMB). Data from 3 505 unique patients with CLTI who had undergone revascularisation from 2013 to 2017 were extracted from the JCLIMB for the analysis. The cohort was randomly divided into development (2 861 patients) and validation cohorts (644 patients). In the development cohort, multivariable risk models were constructed to predict two year OS and AFS using Cox proportional hazard regression analysis. These models were applied to the validation cohort and their performances were evaluated using Harrell's C index and calibration plots.

RESULTS

Kaplan-Meier estimates of two year OS and AFS post-revascularisation in the whole cohort were 69% and 62%, respectively. Strong predictors for OS consisted of age, activity, malignant neoplasm, chronic kidney disease (CKD), congestive heart failure (CHF), geriatric nutritional risk index (GNRI), and sex. Strong predictors for AFS included age, activity, malignant neoplasm, CKD, CHF, GNRI, body temperature, white blood cells, urgent revascularisation procedure, and sex. Prediction models for two year OS and AFS showed good discrimination with Harrell's C indexes of 0.73 (95% confidence interval [CI] 0.69 - 0.77) and 0.72 (95% CI 0.68 - 0.76), respectively CONCLUSION: Prediction models for two year OS and AFS post-revascularisation in patients with CLTI were created. They can assist in determining treatment strategies and serve as risk adjustment modalities for quality benchmarking for revascularisation in patients with CLTI at each facility.

ERICVA Risk Scale simplified as a predictor of amputation in critical limb ischemia

OBJECTIVE

Demonstrate that simplified ERICVA (Valladolid Critical Limb Ischaemia Risk Scale) is useful in predicting amputation in chronic limb-threatening ischemia (CLI) after one year of revascularization.

METHODS

A retrospective cohort study was performed. We analyzed the medical records of 93 patients over the age of 35 with the diagnosis of CLI who were treated in the Department of Internal Medicine, Orthopedics or in the Cardiovascular Surgery Unit of the Víctor Lazarte Echegaray Hospital and the High Complexity Virgen de La Puerta Hospital during the period 2015-2018. The simplified ERICVA score was determined in patients before surgical and endovascular revascularization. We included 31 patients who scored 2 or more points in the exposed group and 62 patients who scored less than 2 points in the group not exposed to amputation risk. The collected data was analyzed with the statistical program SPSS where the Relative Risk and significance was obtained with Pearson's Chi-square. The multivariate analysis was also carried out in order to obtain the adjusted relative risk.

RESULTS

It was identified that the simplified ERICVA score greater than or equal to 2 points was more frequent in those who underwent amputation (90.3%) compared to patients who did not undergo amputation (4.8%), increasing the risk of amputation in those patients with CLI who underwent revascularization (RR: 18.67, P<0.001). It was also possible to identify that within the group of patients that showed a high risk of amputation according to the ERICVA scale, they had a higher risk of major amputation (RR: 9.32, P<0.001) as opposed to the risk of minor amputation (RR: 1, 89, P=0.193). Among the items of the simplified ERICVA scale, the preoperative neutrophil-lymphocyte ratio and hematocrit were significantly higher in the group of amputated patients (P<0.001). In addition, it was possible to identify that the score greater than or equal to 2 was independently associated with the risk of amputation in patients revascularized with CLI (RR: 13.5, P<0.001).

CONCLUSION

In our patient population, the simplified ERICVA scale is useful in predicting major and minor amputation in critical limb ischemia after revascularization. The present data showed that the patients who had a simplified ERICVA score greater than or equal to 2 had a higher risk of major amputation compared to the risk of minor amputation. However, it is important to highlight that the impact on the prediction of minor amputation is greater because in some circumstances major amputation can appear as a complication of CLI.

Applicability of the Vascular Quality Initiative (VQI) mortality prediction model for infrainguinal revascularization in a tertiary limb preservation center population

OBJECTIVE

Patients undergoing revascularization for chronic limb-threatening ischemia (CLTI) are at elevated risk for both mortality and limb loss. To facilitate therapeutic decision-making, a mortality prediction model derived from the Vascular Quality Initiative (VQI) database has stratified patients into low, medium, and high risk, defined by 30-day mortality estimated of ≤3%, 3-5%, or >5% and 2-year mortality estimates of ≤30%, 30-50%, or ≥50%, respectively. The purpose of this study was to compare expected mortality risk derived from this model with observed outcomes in a tertiary center.

METHODS

Consecutive patients treated at a single center between 2016 and 2019 were analyzed. Baseline demographics, approach, and mortality events were reviewed. Observed mortality was obtained using life-table methods and compared using a log-rank test with the expected mortality risk which was calculated using the VQI model.

RESULTS

This study cohort consisted of 195 revascularization procedures in 169 unique patients stratified into 128 (66%) low, 50 (26%) medium, and 17 (8%) high-risk cases based on the VQI model. 90% of revascularizations were performed for tissue loss. Compared with the VQI population, comorbidities were prevalent and included unstable angina or myocardial infarction within 6 months (6% vs. 2.4% in VQI; p<0.001), congestive heart failure (30% vs. 23%; p<0.001), and dialysis dependence (14% vs. 0.9%; p<0.001). Patients were also older (31% vs. 21% ≥80 years old; p<0.001) and more likely to be frail (45% vs. 64% independent; p<0.001). High-risk patients were more prevalent in the endovascular group (11% of 132 endovascular interventions vs. 3% of 63 bypasses; p=0.056). 30-day observed mortality exceeded expected VQI prediction model mortality in all groups, although was not statistically significant. The VQI model adequately stratified the studied population into risk groups (p<0.001). Low risk CLTI patients (65% of the overall cohort) experienced 2- year mortality of 18.9%. However, observed mortality for medium and high-risk VQI strata were similar. After a median follow-up of 28 months, medium-risk patients incurred a significantly higher mortality than predicted (53.5%±2.1% vs. 36.8%±1.1%; p=0.016).

CONCLUSIONS

The VQI mortality prediction model discriminates mortality risk after limb revascularization in CLTI, accurately identifying a majority subgroup of patients who are suitable for either open or endovascular intervention. However, it may underestimate mortality in a tertiary referral population with high comorbidity burden and was not well calibrated for the medium-risk group. It may be more appropriate to dichotomize CLTI patients who are candidates for limb salvage into an average risk and high-risk group.

Risk Models and Scores in Patients with Peripheral Artery Disease and Chronic Limb-threatening Ischemia: A Comprehensive Review

Peripheral artery disease (PAD) affects more than 200 million patients worldwide and chronic limbthreatening ischemia (CLTI) is the most advanced stage of PAD with very high morbidity and mortality rates. Cardiovascular medicine is trending towards a more personalized approach where each individual patient will be managed according to specific risk factors, disease characteristics, expectations related to their disease and individualized assessment of potential outcomes. For this reason, a number of risk models and scores have been developed during the last few years. Our aim in this comprehensive review article is to provide an overview of selected risk models and scores for patients with PAD and CLTI. Given that some of the published scores were of low quality (minimal discriminatory ability), we included scores that were already externally validated or scores that had promising initial findings. Available scoring systems were grouped in the five following categories according to their utility: i) scores that can detect asymptomatic patients who should be screened for PAD, ii) scores for assessment of functional status and quality of life in patients with PAD, iii) scores assessing risk for amputation and other major adverse limb events among patients with CLTI, iv) scores for the optimal revascularization strategy in each patient and scores predicting successful procedural outcomes; v) scores predicting short or long-term cardiovascular and limb related outcomes after either revascularization or at least angiographic assessment. Limitations of available scoring systems include development and validation in specific populations, lack of external validation (for some of them) and also lack of synchrony with current era endovascular technology. However, with further optimization of current scores and the development of new scores, the field of PAD and CLI can be transitioned to a personalized medicine approach.

Risk prediction model for early outcomes of revascularization for chronic limb-threatening ischaemia

BACKGROUND

Quantifying the risks and benefits of revascularization for chronic limb-threatening ischaemia (CLTI) is important. The aim of this study was to create a risk prediction model for treatment outcomes 30 days after revascularization in patients with CLTI.

METHODS

Consecutive patients with CLTI who had undergone revascularization between 2013 and 2016 were collected from the JAPAN Critical Limb Ischemia Database (JCLIMB). The cohort was divided into a development and a validation cohort. In the development cohort, multivariable risk models were constructed to predict major amputation and/or death and major adverse limb events using least absolute shrinkage and selection operator logistic regression. This developed model was applied to the validation cohort and its performance was evaluated using c-statistic and calibration plots.

RESULTS

Some 2906 patients were included in the analysis. The major amputation and/or mortality rate within 30 days of arterial reconstruction was 5.0 per cent (144 of 2906), and strong predictors were abnormal white blood cell count, emergency procedure, congestive heart failure, body temperature of 38°C or above, and hemodialysis. Conversely, moderate, low or no risk in the Geriatric Nutritional Risk Index (GNRI) and ambulatory status were associated with improved results. The c-statistic value was 0.82 with high prediction accuracy. The rate of major adverse limb events was 6.4 per cent (185 of 2906), and strong predictors were abnormal white blood cell count and body temperature of 38°C or above. Moderate, low or no risk in the GNRI, and age greater than 84 years were associated with improved results. The c-statistic value was 0.79, with high prediction accuracy.

CONCLUSION

This risk prediction model can help in deciding on the treatment strategy in patients with CLTI and serve as an index for evaluating the quality of each medical facility.

Outcomes of Lower Extremity Endovascular Revascularization: Potential Predictors and Prevention Strategies

Peripheral artery disease (PAD) is a manifestation of atherosclerosis, which may affect arteries of the lower extremities. The most dangerous PAD complication is chronic limb-threatening ischemia (CLTI). Without revascularization, CLTI often causes limb loss. However, neither open surgical revascularization nor endovascular treatment (EVT) ensure long-term success and freedom from restenosis and revascularization failure. In recent years, EVT has gained growing acceptance among all vascular specialties, becoming the primary approach of revascularization in patients with CLTI. In clinical practice, different clinical outcomes after EVT in patients with similar comorbidities undergoing the same procedure (in terms of revascularization technique and localization of the disease) cause unsolved issues that need to be addressed. Nowadays, risk management of revascularization failure is one of the major challenges in the vascular field. The aim of this literature review is to identify potential predictors for lower extremity endovascular revascularization outcomes and possible prevention strategies.

Impact of impaired ambulatory capacity on the outcomes of peripheral vascular interventions among patients with chronic limb-threating ischemia

OBJECTIVE

Despite prior literature recommending against limb salvage in patients with poor functional status such as nonambulatory patients with chronic limb-threatening ischemia (CLTI), peripheral endovascular interventions continue to be carried out in this group of patients. Clinical outcomes following these interventions are, however, not well-characterized.

METHODS

A retrospective review was conducted on all patients treated for CLTI in the Vascular Quality Initiative from September 2016 to December 2019. Logistic regression, Kaplan-Meier survival estimates, log-rank tests, and Cox regression analyses were used as appropriate to study outcomes. The primary outcomes were 30-day mortality and 1-year amputation-free survival. The secondary outcomes were in-hospital death, postoperative complications, 1-year freedom from major amputation, and 2-year survival.

RESULTS

Of the 49,807 patients studied, 28,469 (57.2%) were ambulatory, 15,148 (31.0%) were ambulatory with assistance, 5395 (10.8%) were wheelchair bound, and 525 (1.1%) were bedridden. There was a 2-fold increase in the odds of 30-day death in patients who were ambulatory with assistance (odds ratio [OR], 2.03; 95% confidence interval [CI], 1.77-2.34; P < .001) and wheelchair-bound patients (OR, 2.09; 95% CI, 1.74-2.51; P < .001), and a more than 6-fold increase in bedridden patients (OR, 6.28; 95% CI, 4.55-8.65; P < .001) compared with ambulatory patients. There was a significantly higher odds of postoperative complications in patients who were ambulatory with assistance or bedridden, but no difference with wheelchair-bound patients. Among ambulatory patients, the risks of major amputation and death within 1 year were only 10% and 12%, respectively, whereas that of bedridden patients were as high as 30% and 38%, respectively. A stepwise decrease in amputation-free survival from 81% with full ambulatory capacity to less than 50% (47.7%) in bedridden patients was observed. The risk of major amputation or death within 1 year was 35% higher for ambulatory with assistance (hazard ratio [HR], 1.35; 95% CI, 1.26-1.44; P < .001), 65% higher for wheelchair-bound (HR, 1.65; 95% CI, 1.51-1.79; P < .001) and 2.6-fold higher for bedridden (HR, 2.64; 95% CI, 2.17-3.21; P < .001) compared with ambulatory. A similar association was seen for 1-year freedom from major amputation and 2-year survival.

CONCLUSIONS

Ambulatory impairment in patients with CLTI is associated with a significant increase in 30-day mortality and significant decrease in amputation-free survival after peripheral endovascular intervention. Bedridden patients had a 6-fold increase in the 30-day death rate, whereas their amputation-free survival dropped to less than 50% at 1 year. These risks should be considered during shared decision-making regarding management options for nonambulatory patients with CLTI.

Preoperative Stress Test and Postoperative MI in Patients Requiring Lower Extremity Bypass for Critical Limb Ischemia

BACKGROUND

Patients with critical limb ischemia (CLI) often require lower extremity bypass surgery for limb salvage. A myocardial infarction (MI) is a major postoperative risk. Our objective is to assess the utility of preoperative stress test in determining patient outcomes.

METHODS

This is a retrospective study utilizing the national Vascular Quality Initiative database. We collected data from 2013-2018 on all patients undergoing lower extremity bypass for CLI and assessed whether or not they had a preoperative stress test. Rates of an MI were then compared between groups of patients who either did not receive a stress test, had a normal stress test or a positive stress test. An MI was distinguished as troponin only and electrocardiogram (EKG)/clinical. Our secondary end point was in-hospital mortality. Univariate and multivariate analysis with the stress test as a covariate was used to determine significance.

RESULTS

During this time period, 29,937 bypasses were performed on 27,219 patients. The average age was 67.5 years (±11.09), 66.3% were men, and 17.3% were African American. Risk factors included hypertension (89.5%), diabetes (55.9%), congestive heart failure (20%), coronary artery disease (32.5%), coronary artery bypass graft (22.2%), and percutaneous coronary intervention (21%). 19,108 patients (64.1%) did not undergo the stress test before bypass, 6,830 (22.9%) had a normal stress test, and 2,898 (9.7%) had a positive stress test. Overall rate of an MI was 4%, with 2% being troponin only and 2% EKG/clinical. The positive stress test had a higher rate of troponin only (2.85%) as well as EKG/clinical (3.37%) MI. For every 10 year increase in age, the odds of having a postoperative MI increased by 27% (P < 0.0001). Overall in-hospital mortality was 1.4%. Patients with positive stress tests had a 2.6% mortality compared with normal/not performed at 1.3%. Of the patients who died, 21.5% had an EKG/clinical MI. Of those patients, 50% did not have a stress test, 12% had normal stress tests, and 23% had positive stress tests. When comparing rates of patients who died or had an MI, there was no difference between patients who had no or a normal stress test (7.29%) versus those who had a positive stress test (7.58%), (P = 0.11).

CONCLUSIONS

A positive stress test before lower extremity bypass is a significant predictor of a postoperative MI. However, mortality increase was minimal in patients with a positive stress test. Therefore, the stress test result should not delay care for patients needing urgent revascularization.

Long-Term Results and Risk Analysis of Redo Distal Bypass for Critical Limb Ischemia

BACKGROUND

Distal bypass is the optimal treatment for patients with critical limb ischemia (CLI). However, effectiveness of redo distal bypass (rDB) after failed initial distal bypass (iDB) remains uncertain. This study aimed to analyze long-term results of rDB for CLI.

METHODS

Patients undergoing rDB for CLI from 2009 to 2018 at a single institute were retrospectively reviewed. Operative details, primary and secondary patency, survival rate, major amputation-free rate, and risk factors affecting patency were analyzed. The distal runoff was evaluated using the infrapopliteal Global Limb Anatomic Staging System (GLASS) grade (0 to 4: 0 represents good runoff and 4 represents the poorest runoff).

RESULTS

Of 310 iDB (251 patients), 46 rDB were performed in 44 patients: 27 men, mean age 75 ± 10 years, diabetes mellitus 77%, chronic renal failure with hemodialysis 45%. Only the autologous veins were used in distal bypasses: a great saphenous vein (GSV) in 28 (57%), a small saphenous vein in 13 (27%), an arm vein in 6 (12%), and a superficial femoral vein in 2 (4%). The GSV was used less frequently for rDB than for iDB (57% vs. 90%, P < 0.0001). The infrapopliteal GLASS grade 4 was recognized more in rDB than iDB (76% vs. 60%, P = 0.04). Primary and secondary patency of rDB was 25% and 44% at 1 year and 14% and 29% at 3 years, respectively, which were significantly lower than those of iDB (P < 0.0001). The survival rate after rDB was 68% at 1 year and 53% at 3 years. Freedom from major amputation rate in rDB was 83% at 1 year and 66% at 3 years. Multivariate analysis showed the risk factor influencing on secondary patency was patent duration of the iDB graft (P = 0.012). Secondary patency of rDB was higher in the group of late graft occlusion ≥6 months after iDB (late group) than in the group of early graft occlusion < 6 months after iDB (early group) (94% vs. 9% at 1 year and 75% vs. 5% at 3 years, P < 0.0001). However, freedom from major amputation rate at 3 years was comparable between both groups (71% in the late group vs. 61% in the early group).

CONCLUSIONS

Patency of rDB was significantly lower than that of iDB partly because of less use of the GSV and poorer runoff. Because survival and graft patency after rDB was low, rDB should be a suboptimal treatment especially in patients with early graft occlusion within 6 months after iDB.

External validation of the Vascular Quality Initiative prediction model for survival in no-option chronic limb-threatening ischemia patients

OBJECTIVE

Chronic limb-threatening ischemia (CLTI) is associated with high morbidity and mortality rates. More than 50% of all CLTI patients die within 5 years after presentation. Patient-specific survival prediction is critical for informing treatment strategies, even for those without a clear option for revascularization. We validated a survival prediction model, developed in a revascularized Vascular Quality Initiative (VQI) cohort, in a Western European no-option CLTI cohort.

METHODS

The VQI survival prediction model was applied to the validation cohort (N = 150) to compare estimated mortality and observed mortality at 2 years after baseline. Performance of the VQI model was tested by evaluating discrimination using the receiver operating characteristic area under the curve and calibration using the Hosmer-Lemeshow goodness-of-fit test.

RESULTS

The 2-year survival rate was 79% in the validation cohort compared with 83% in the VQI cohort. Baseline characteristics were significantly different for 13 of 17 variables. The C statistic was 0.86 (95% confidence interval, 0.78-0.95), which indicates good discrimination. The Hosmer-Lemeshow goodness-of-fit test had a P value of .30, which indicates good fit.

CONCLUSIONS

This is the first external validation of the VQI survival prediction model. The good model performance suggests that this model can be used in different CLTI populations, including no-option CLTI, and underlines its contributory role in this challenging population.

The patient presenting with chronic limb-threatening ischaemia. Does diabetes influence presentation, limb outcomes and survival?

Peripheral arterial disease (PAD) confers an elevated risk of major amputation and delayed wound healing in diabetic patients with foot ulcers. The major international vascular societies recently developed evidence-based guidelines for the assessment and management of patients with chronic limb-threatening ischaemia (CLTI). CLTI represents the cohort of diabetic and non-diabetic patients who have PAD which is of sufficient severity to delay wound healing and increase amputation risk. Diabetic patients with CLTI are more likely to present with tissue loss, infection and have less favourable anatomy for revascularization than those without diabetes. Although diabetes is not consistently reported as a strong independent risk factor for limb loss, major morbidity and mortality in CLTI patients, it is impossible in clinical practice to isolate diabetes from comorbidities, such as end-stage renal disease and coronary artery disease which occur more commonly in diabetic patients. Treatment of CLTI in the diabetic patient is complex and should involve a multi-disciplinary team to optimize outcomes. Clinicians should use an integrated approach to management based on patient risk assessment, an assessment of the severity of the foot pathology and a structured anatomical assessment of arterial disease as suggested by the Global Vascular Guidelines for CLTI.

Global Vascular Guidelines on the Management of Chronic Limb-Threatening Ischemia

GUIDELINE SUMMARY

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Global vascular guidelines on the management of chronic limb-threatening ischemia

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Limitations of Vascular Quality Initiative-derived models to predict the outcomes of intervention for infrapopliteal limb-threatening ischemia

OBJECTIVE

The purpose of this study was to validate published Society for Vascular Surgery Vascular Quality Initiative (VQI) prediction models for patients with limb-threatening ischemia (LTI) undergoing open or endovascular revascularization for infrapopliteal occlusive disease.

METHODS

We sought to validate our prior VQI LTI models for major adverse limb events (MALEs) and amputation-free survival (AFS) in a VQI new cohort undergoing open or percutaneous interventions from September 2014 through August 2016. Receiver operating characteristic curves were generated including the C statistic, and the predicted vs actual outcomes were correlated. The Hosmer-Lemeshow (HL) statistic was calculated to determine goodness of fit, and the Tjur R² statistic was derived to demonstrate the degree to which the observed outcomes were accurately predicted by the models.

RESULTS

Of 15,576 open infrainguinal and 34,679 percutaneous interventions collected in the VQI during the 24-month interval, 8852 and 17,124, respectively, were performed for LTI, among which 4410 and 5116 specifically targeted the infrapopliteal vessels. MALEs and AFS were identified for 400 of 927 (43.1%) and 576 of 982 (58.7%) open procedures and 197 of 855 (23.0%) and 658 of 1115 (59.0%) percutaneous procedures, respectively. For open operation, the predictive ability of the model was poor for MALEs (C = 0.59; HL = 107; R² = 0.03) and only marginally better for AFS (C = 0.69; HL = 130; R² = 0.10). Similarly, for endovascular intervention, the model performed poorly for MALEs (C = 0.62; HL = 183; R² = 0.06) and slightly better for AFS (C = 0.68; HL = 68; R² = 0.11). Breaking AFS into its component determinants, the predictive ability of the open operation model for patient survival (C = 0.77; HL = 70; R² = 0.15) surpassed that for limb salvage (C = 0.64; HL = 54; R² = 0.05). For endovascular interventions, the survival model (C = 0.71; HL = 94; R² = 0.11) also outperformed the limb salvage model (C = 0.67; HL = 28; R² = 0.07). For both types of intervention, the actual MALE rate was lower and AFS was higher than predicted by the models.

CONCLUSIONS

The ability of reported VQI-derived models to accurately predict major outcomes for infrapopliteal LTI is limited and cannot be advocated for clinical decision-making at this time. Further study would be necessary to determine whether this is due to intraoperative and postoperative variables not accounted for in our models, absence of pertinent data points from the registry, or incomplete follow-up.

Regional variation in outcomes for lower extremity vascular disease in the Vascular Quality Initiative

BACKGROUND

Increased focus has been placed on perioperative and long-term outcomes in the treatment of peripheral artery disease (PAD), both for purposes of quality improvement and for assessment of performance at a surgeon and institutional level. This study evaluates regional variation in outcomes after treatment for PAD within the Vascular Quality Initiative (VQI). By describing the variation in practice patterns and outcomes across regions, we hope that each regionally based quality group can select which areas are most important for them to focus on as they will have access to their regional data to compare.

METHODS

We identified all patients in the VQI who had infrainguinal bypass or endovascular intervention from 2009 to 2014. We compared variation in perioperative and 1-year outcomes stratified by symptom status and revascularization type among the 16 regional groups of the VQI. We analyzed variation in perioperative end points using χ2 analysis, and 1-year end points were analyzed using Kaplan-Meier and life-table analysis.

RESULTS

We identified 15,338 bypass procedures for symptomatic PAD: 27% for claudication, 59% for chronic limb-threatening ischemia (CLI; 61% of these for tissue loss), and 14% for acute limb ischemia. We identified 33,925 endovascular procedures for symptomatic PAD: 42% for claudication, 48% for CLI (73% of these for tissue loss), and 10% for acute limb ischemia. Thirty-day mortality varied significantly after endovascular intervention for CLI (0.5%-3%; P < .001) but not for claudication (0.0%-0.5%, P = .77) or for bypass for claudication (0.0%-2.6%; P = .37) or CLI (0.0%-5.0%; P = .08). After bypass, rates of >2 units transfused red blood cells (claudication, 0.0%-13% [P < .001]; CLI, 6.9%-27% [P < .001]) varied significantly. In-hospital major amputation was variable after bypass for CLI (0.0%-4.3%; P = .004) but not for claudication (0.0%-0.6%; P = .98), as was postoperative myocardial infarction (claudication, 0.0%-4% [P = .36]; CLI, 0.8%-6% [P = .001]). One-year survival varied significantly for endovascular interventions for claudication (92%-100%; P < .001), bypass for CLI (85%-94% [P < .001]), and endovascular interventions for CLI (77%-96%; P < .001) but not after bypass for claudication (95%-100%; P = .57).

CONCLUSIONS

In this real-world comparison among VQI regions, we found significant variation in perioperative and 1-year end points for patients with PAD undergoing bypass or endovascular intervention. This study highlights opportunities for quality improvement efforts to reduce variation and to improve outcomes.

Long-term outcomes in patients with critical limb ischemia and heart failure with preserved or reduced ejection fraction

The impact of heart failure (HF) on long-term survival in patients with critical limb ischemia (CLI) has not been well described. Outcomes stratified by left ventricular ejection fraction (EF) are also unknown. A single center retrospective chart review was performed for patients who underwent treatment for CLI from 2006 to 2013. Baseline demographics, procedural data and outcomes were analyzed. HF diagnosis was based on appropriate signs and symptoms as well as results of non-invasive testing. Among 381 CLI patients, 120 (31%) had a history of HF and 261 (69%) had no history of heart failure (no-HF). Within the HF group, 74 (62%) had HF with preserved ejection fraction (HFpEF) and 46 (38%) had HF with reduced ejection fraction (HFrEF). The average EF for those with no-HF, HFpEF and HFrEF were 59±13% vs 56±9% vs 30±9%, respectively. The likelihood of having concomitant coronary artery disease (CAD) was lowest in the no-HF group (43%), higher in the HFpEF group (70%) and highest in the HFrEF group (83%) ( p=0.001). Five-year survival was on average twofold higher in the no-HF group (43%) compared to both the HFpEF (19%, p=0.001) and HFrEF groups (24%, p=0.001). Long-term survival rates did not differ between the two HF groups ( p=0.50). There was no difference in 5-year freedom from major amputation or freedom from major adverse limb events between the no-HF, HFpEF and HFrEF groups, respectively. Overall, the combination of CLI and HF is associated with poor 5-year survival, independent of the degree of left ventricular systolic dysfunction.

Risk factors for wound complications and 30-day mortality after major lower limb amputations in patients with peripheral arterial disease

Purpose Risk factors for wound complications or 30-day mortality after major amputation in patients with peripheral arterial disease remain unclear. We investigated the outcomes of major amputation in patients with peripheral arterial disease. Methods Patients who underwent major amputation from 2008 to 2015 were retrospectively analyzed. The main outcome measures were risk factors for wound complications and 30-day mortality after major lower limb amputations. Major amputation was defined as above-knee amputation or below-knee amputation. Wound complications were defined as surgical site infection or wound dehiscence. Results In total, 106 consecutive patients underwent major amputation. The average age was 77.3 ± 11.2 years, 67.9% of patients had diabetes mellitus and 35.8% were undergoing hemodialysis. Patients who underwent primary amputation constituted 61.9% of the cohort, and the proportions of above-knee amputation and below-knee amputation were 66.9% and 33.1%, respectively. The wound complication rate was 13.3% overall, 10.3% in above-knee amputation, and 19.5% in below-knee amputation. Multivariate analysis showed that the risk factors for wound complications were female sex (hazard ratio, 4.66; 95% confidence interval, 1.40-17.3; P = 0.01) and below-knee amputation (hazard ratio, 4.36; 95% confidence interval, 1.20-17.6; P = 0.03). The 30-day mortality rate was 7.6%, pneumonia comprised the most frequent cause of 30-day mortality, followed by sepsis and cardiac death. Multivariate analysis showed that a low serum albumin concentration (hazard ratio, 3.87; 95% confidence interval, 1.12-16.3; P = 0.03) was a risk factor for 30-day mortality. Conclusions Female sex and below-knee amputation were risk factors for wound complications. A low serum albumin concentration was a risk factor for 30-day mortality after major amputation in Japanese patients with peripheral arterial disease.

Infrainguinal open reconstruction: a review of surgical considerations and expected outcomes

Infrainguinal arterial occlusive disease can lead to potentially disabling and limb-threatening conditions. Revascularization may be indicated for claudication, rest pain, or tissue loss. Although endovascular interventions are becoming more prevalent, open surgeries such as endarterectomy and bypass are still needed and performed regularly. Open reconstruction has been associated with postoperative morbidity, both at the local and at the systemic levels. Local complications include surgical site infections (SSIs 0-5.3%), graft failure (12-60%), and amputation (5.7-27%), and more systemic issues include cardiac (2.6-18.4%), respiratory (2.5%), renal (4%), neurovascular (1.5%), and thromboembolic (0.2-1%) complications. While such outcomes present an additional challenge to the postoperative management of surgical patients, it may be possible to minimize their occurrence through careful risk stratification and preoperative assessment. Therefore, individualized selection of candidates for open repair requires weighing the need for intervention against the likelihood of adverse outcomes based on preoperative risk factors. This review provides an overview of open reconstruction, focusing on identifying the clinical indications for surgery and perioperative morbidity and mortality.

Risk factors analysis of thromboembolectomy for acute thromboembolic lower extremity ischemia in native arteries

BACKGROUND

Aim of this study is to report the results of thromboembolectomy (ThEmb) for acute thromboembolic lower limb ischemia (ATLI) in native arteries and to create a predictive score for amputation-free survival (AFS) at 30 days.

METHODS

It is a single center, retrospective analysis of a four years period. All patients had ThEmb: adjunctive procedures included femoral and/or popliteal endarterectomy in 30 (18.3%) cases, PTA-stent in 24 (14.6%), and femoral endarterectomy plus PTA-stent in 12 (7.3%). Fasciotomies were performed in 6 (3.6%) patients. Predictors of AFS identified on univariate screen (inclusion threshold, P<.20) were included in a multivariable model. The resulting significant predictors were assigned an integer score to stratify patients into risk groups.

RESULTS

Authors analyzed 164 limbs in 164 patients. Mean age was 80±10 years (range, 40-99). In-hospital mortality was 9.8% (N.=16); AFS at 30 days was 84.7% (N.=139). The anatomic level (iliac vs. femoropopliteal vs. infrapopliteal) of the occlusion did not affect AFS (P=.326). Multivariable analysis identified six significant predictors of AFS at 30 days: age >85 (P=0.050), chronic obstructive pulmonary disease (P=0.008), chronic renal insufficiency (P=0.019), late (>6 hours) onset (P=0.004), the presence of major neurologic deficit (P=0.023), and an increased (>800IU/L) level of creatine phosphokinase (P=0.001). An integer score generated two risk groups (low-risk 0-2 [70.1% of cohort], and high-risk ≥3 [29.9% of cohort]): stratification of the patients according to risk category yielded significantly different AFS at 30 days (low-risk 5.2% vs. high-risk 38.8%, P<0.0001).

CONCLUSIONS

Among patients selected to undergo ThEmb for ATLI in native arteries, this risk score identified a group of patients with a 40% chance of death or major amputation at 30 days. The score can help to optimize the operative strategy, but further prospective validation is needed.

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.

[Indications and results of endovascular therapy of critical limb ischemia]

BACKGROUND

Critical limb ischemia (CLI) is the most severe form of peripheral artery occlusive disease and is characterized by high amputation, morbidity and mortality rates. Therefore, revascularization is the essential step in therapy for retention of the affected limb.

OBJECTIVES

Although for a long time bypass surgery represented the gold standard in the treatment of CLI, in recent years there has been a disproportionate increase of endovascular treatment despite the lack of level-data. In this review the indications and results of endovascular therapy of CLI are presented on the basis of published data.

METHODS

A literature search was carried out to identify publications that compared the results of endovascular and surgical therapy as well as observational studies about different endovascular techniques.

RESULTS

The BASIL study provided the highest quality data comparing endovascular and surgical treatment of CLI. The long-term data of the BASIL trial showed that apart from patients with a suitable vein and a life expectancy of more than 2 years, first line endovascular therapy is equivalent to surgical treatment. The equivalence could also be demonstrated in a meta-analysis comparing operative and endovascular treatment of CLI.

CONCLUSION

The CLI is a disease with high mortality and morbidity risks. Due to the comparable amputation-free survival times with lower complication rates in the published data, in most patients an endovascular first strategy in experienced centers can be justified.

Using implementation science to help integrate preoperative evidence-based measures into practice for vascular surgery patients

The preoperative workup is a necessary and crucial evaluation for patients undergoing major vascular surgery. It is important to assess for likelihood of perioperative adverse events and then implement evidence-based measures to reduce identified medical comorbidities and improve the quality of patient care and outcomes after surgery. Although there are numerous opportunities to implement evidence-based processes during the preoperative period, there are many barriers that can prevent vascular surgeons from achieving these goals. This review will discuss how an implementation science-based approach can be used by members of the vascular surgery team to identify appropriate preoperative evidence-based interventions for diverse practice settings and to overcome barriers and allow integration of these interventions as part of the routine preoperative workup.

Design of a New Risk Score in Critical Limb Ischaemia: The ERICVA Model

OBJECTIVES

It is difficult to establish which patients suffering from critical lower limb ischaemia will benefit from revascularization. Risk scores can provide objectivity in decision making. The aim was to design a new risk score (ERICVA) and compare its predictive power with the PREVENT III and Finnvasc scores.

METHODS

An observational retrospective study of patients who underwent revascularization (open or endovascular) in Valladolid's University Hospital between 2005 and 2010 was designed. The sample was divided into two subgroups (development and validation subsamples). After univariate analysis followed by a multivariate Cox regression, a number of variables associated with death and/or major amputation were selected, creating a weighed score called ERICVA, and a simplified version of it. The area under the curve (AUC) of receiver operating characteristic (ROC) curve analysis was performed and the AUC of these two scores were additionally compared with the AUC of the PREVENT III and Finnvasc scales.

RESULTS

Six hundred and seventy two cases with an average surveillance of 778 days were included in the study. Amputation free survival (AFS) was 84.8% at 30 days and 63.1% at 1 year. Variables associated with death and/or major amputation in the Cox regression were cerebrovascular disease, prior contralateral major amputation, diabetes mellitus, dialysis, chronic obstructive pulmonary disease, cancer, haematocrit less than 30%, neutrophil/lymphocyte ratio exceeding 5, absence of arterial Doppler signal at the ankle, emergency admission, and Rutherford stage 6; these variables were used for the ERICVA and simplified ERICVA score designs. Scores were applied to both subsamples; in the development sample the AUC of ERICVA and simplified ERICVA was significantly higher than the PREVENT III (p = .008 and p = .045) and Finnvasc (p < .0001 and p = .0013) scores; in the validation sample the AUC of ERICVA and simplified ERICVA were significantly higher than Finnvasc score (p = .0323 and p = .0017).

CONCLUSIONS

The ERICVA model has a good predictive capacity for death and/or major amputation in the clinical setting, and is better than the PREVENT III and Finnvasc scores.

Incidence and Predictors of Cardiovascular Complications and Death after Vascular Surgery

BACKGROUND

Patients undergoing arterial vascular surgery are considered at increased risk for post-operative complications.

OBJECTIVE

To assess the incidence and predictors of complications and death, as well as the performance of two models of risk stratification, in vascular surgery.

METHODS

This study determined the incidence of cardiovascular complications and deaths within 30 days from surgery in adults. Univariate comparison and logistic regression assessed the risk factors associated with the outcomes, and the receiver operating characteristic (ROC) curve assessed the discriminatory capacity of the revised cardiac risk index (RCRI) and vascular study group of New England cardiac risk index (VSG-CRI).

RESULTS

141 patients (mean age, 66 years; 65% men) underwent the following surgeries: carotid (15); lower limbs (65); abdominal aorta (56); and others (5). Cardiovascular complications and death occurred within 30 days in 28 (19.9%) and 20 (14.2%) patients, respectively. The risk predictors were: age, obesity, stroke, poor functional capacity, altered scintigraphy, surgery of the aorta, and troponin change. The scores RCRI and VSG-CRI had area under the curve of 0.635 and 0.639 for early cardiovascular complications, and 0.562 and 0.610 for death in 30 days.

CONCLUSION

In this small and selected group of patients undergoing arterial vascular surgery, the incidence of adverse events was elevated. The risk assessment indices RCRI and VSG-CRI did not perform well for complications within 30 days.

Current accepted hemodynamic criteria for critical limb ischemia do not accurately stratify patients at high risk for limb loss

OBJECTIVE

Critical limb ischemia (CLI) has been defined as rest pain or tissue loss in patients who have an ankle-brachial index (ABI) ≤0.50, ankle pressure (AP) <70 mm Hg, or toe pressure (TP) <50 mm Hg. Data suggesting that these patients are at high risk for limb loss without successful revascularization are limited. This study was designed to identify limb loss and mortality rates in patients who did not respond to revascularization or who were not revascularized to determine whether CLI hemodynamic criteria accurately identify patients at high risk for limb loss.

METHODS

Between 2008 and 2010, all patients undergoing lower extremity arterial duplex ultrasound testing at our hospital were identified. Those with ABI <0.50, AP <70 mm Hg, or TP <50 mm Hg were retrospectively reviewed to determine whether they had symptoms of rest pain, ischemic ulceration, or gangrene qualifying them for analysis in the database. Patients who underwent revascularization and subsequently had postrevascularization ABI, AP, or TP greater than the CLI criteria were removed from the cohort. Demographic factors, wound healing, amputation rates, and mortality were obtained and analyzed in relation to the initial APs and TPs. Outcomes were measured by Kaplan-Meier life-table analysis and Cox proportional hazards models.

RESULTS

In 381 patients identified in the study, 443 limbs met CLI criteria. After revascularization, 98 limbs with ABI or TP that improved to >0.5 and >50 mm Hg, respectively, were removed from the study cohort. In 45 limbs, patients did not respond to initial revascularization as their ABI, AP, or TP remained within CLI criteria. These limbs remained in the patient cohort, yielding a final group of 296 patients and 345 limbs. Mean follow-up was 2 years. In the entire patient cohort, limb loss occurred in 24% at 1 year and in 31% at 3 years. Mortality was 32% at 1 year and 56% at 3 years. Amputation-free survival was 54% at 1 year and 28% at 3 years. Lower TPs were associated with a statistically higher incidence of amputation. Among those with an initial TP ≤10 mm Hg (n = 85), limb loss occurred in 46% at 1 year and 60% at 3 years. This limb loss was significantly greater than limb loss among those with a TP of 31 to 50 mm Hg (n = 115; 18% at 3 years; P < .001) Amputation-free survival in patients with a TP ≤10 mm Hg was 8% at 3 years.

CONCLUSIONS

CLI is associated with a high mortality, but not all patients with currently defined hemodynamic criteria for CLI are at high risk of limb loss. Patients with a TP between 31 and 50 mm Hg (41% of the cohort) and not receiving revascularization or not responding hemodynamically to revascularization experienced a low risk of limb loss. We recommend revising the hemodynamic criteria for CLI to better identify patients at high risk for limb loss who require intervention to improve outcomes.

Defining risks and predicting adverse events after lower extremity bypass for critical limb ischemia

Successful treatment of patients with critical limb ischemia (CLI), hinges on the adequacy of revascularization. However, CLI is associated with a severe burden of systemic atherosclerosis, and patients often suffer from multiple cardiovascular comorbidities. Therefore, CLI patients in general represent a cohort at increased risk for procedural complications and adverse events. Although endovascular therapy represents a minimally invasive alternative to open surgical bypass, the durability of surgical reconstruction is superior, and it remains the "gold standard" approach to revascularization in CLI. Therefore, selection of the optimal treatment modality for individual patients requires careful consideration of the procedural risks and likelihood of adverse events associated with surgery. Individualized decision-making with regard to revascularization strategy requires a comprehensive understanding of the likelihood of adverse outcomes after major surgery. Here we review the risks of surgical bypass in patients with CLI, with particular emphasis on the identification of preoperative variables that predict poor outcome.