Prediction of the Technical Success of Endovascular Therapy in Patients with Critical Limb Threatening Ischaemia Using the Global Limb Anatomical Staging System

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.

Popliteal-Distal Bypass Affords Better Limb Salvage than Tibial Angioplasty for Chronic Limb-Threatening Ischemia

OBJECTIVE

Chronic limb-threatening ischemia (CLTI) due to isolated tibial occlusive disease is treated by either popliteal distal bypass or tibial angioplasty, although there is limited data directly comparing efficacy and outcomes between these two treatment modalities. This study compares 30-day mortality and major adverse limb events following infrapopliteal bypass and tibial angioplasty in patients with CLTI.

METHODS

Patients who underwent popliteal distal bypass for CLTI were extracted from American College of Surgeons National Surgical Quality Improvement Program targeted lower extremity open database, whereas patient with CLTI who underwent isolated tibial angioplasty were identified in the targeted lower extremity endovascular database. Any case with more proximal angioplasty such as femoral/pop/iliac was excluded. The time interval was 2011-2022. The two groups were comparable in demographics and pre-operative comorbidities were obtained using propensity matching. Mortality, systemic complications, and major adverse limb events were measured. Multivariable logistic regression was used for data analysis. To obtain granular data on the angiographic characteristics of patients undergoing popliteal-distal bypass or tibial angioplasty, The George Washington University institutional data from 2014 to 2019 was used as supplement to the database.

RESULTS

There were 1,947 and 3,423 cases identified in the bypass and endovascular groups, respectively. After propensity matching for all preoperative variables, 1,747 cases remained in each group. Although bypass was associated with higher major adverse cardiovascular events, pulmonary, renal, and wound complications, bypass had significantly better 30-day limb salvage when compared to tibial angioplasty (major amputation rate 3.32% vs. 6.12%; p<0.01). Institutional data identified 69 patients with CLTI due to isolated tibial occlusive disease; 25 (36.2%) underwent popliteal-distal bypass and 44 (63.8%) underwent tibial angioplasty. Reviewing of angiographic details revealed patients who underwent popliteal-distal bypass had better pedal targets (inframalleolar/pedal score of P0 [24.0% vs 15.9%] or P1 [68.0% vs 61.3%]) than tibial angioplasty patients (inframalleolar/pedal score of P2 [22.7% vs 8.0%]).

CONCLUSION

Popliteal-distal bypass was associated with higher morbidity but better limb salvage than endovascular interventions. However, this could be explained by the association with better pedal targets in patients who underwent popliteal-tibial bypass. Prospective studies should be done comparing popliteal distal bypasses and tibial angioplasty in cases with similar pedal targets.

Study on mid-term outcomes of atherectomy for patients with femoral popliteal artery lesions with different Global Limb Anatomic Staging System grades

Objective

To investigate the mid-term efficacy and patency rate of TurboHawk peripheral plaque excision system in the treatment of femoral popliteal artery lesions with different Global Limb Anatomic Staging System (GLASS) grades.

Methods

The clinical data of 141 patients with femoral popliteal arteriosclerosis obliterans who were treated with TurboHawk from January 2018 to July 2022 in our institution were retrospectively analyzed. There were 109 male patients and 32 female patients. Recordings were made of the patient's symptoms of limb ischemia, technical success rate, primary patency rate of target vessels, ankle brachial index (ABI), GLASS grades, postoperative complications, and a statistical analysis with the patient's preoperative treatment was conducted.

Results

All patients had improved limb ischemia symptoms to varying degrees after surgery, with a technical success rate of 100% (femoral artery puncture and superficial femoral artery recanalization) without bleeding, hematoma, pseudoaneurysm, arteriovenous fistula or other complications. The follow-up period was 1-24 months, during which the severity of claudication, resting pain, and toe ulcers significantly improved. The primary patency rate of the target vessel was 98.58% (139/141), and the ABI significantly increased on the second day, three months, and six months after surgery compared to before surgery. No major adverse events were found during follow-up. The patency rates at 1, 6, 12 and 24 months after intervention were 100%, 80%, 75% and 60% respectively.

Conclusion

The mid-term efficacy and patency rate of TurboHawk in the treatment of femoral popliteal artery lesions with GLASS I patients have the best mid-term prognosis, the highest mid-term survival rate, and the highest vascular patency. The plaque removal system has proven to be an effective treatment for individual localized chronic total occlusion lesions. Additionally, the TurboHawk system provides a safe and minimally invasive treatment alternative for superficial femoral artery conditions, achieving significant therapeutic results within a brief period.

Endovascular Management of Chronic Limb-Threatening Ischemia (CLTI) in the Elderly: A Focus on Frailty, Wound Healing, and Outcomes

BACKGROUND

In India, a significant scarcity of published data exists regarding chronic limb-threatening ischemia (CLTI) and its management, especially among the elderly population. CLTI, often accompanied by frailty poses a significant healthcare challenge. While endovascular interventions offer hope, there remains a dearth of outcome data for this age group. This study seeks to address this critical gap by investigating the impact of frailty on outcomes, emphasizing amputation-free survival (AFS), wound healing, and health-related quality of life (HRQoL).

METHODS

Our study included 131 elderly CLTI patients aged ≥70 years who underwent infrainguinal endovascular interventions between April 2018 and August 2021, with a follow-up period of 2 years. Among the patients, 93.9% had diabetes mellitus and 82.4% had hypertension. Clinical frailty was assessed using the clinical frailty scale (CFS). Patients were categorized into group 1 (CFS 1-5) and group 2 (CFS 6-9). Primary outcomes were AFS, wound healing, HRQoL, and their association with frailty. Secondary outcomes included technical success, procedure-related complications, major adverse limb events, major adverse cardiac events, vessel patency, re-intervention rates, and mortality rates including periprocedural and overall mortality.

RESULTS

Technical success was achieved in 86.3% of patients, with frailty significantly influencing this outcome. Group 2 exhibited reduced technical success (80.8%) compared to group 1 (93.1%). The major amputation rate was 9.2%, with higher rates in group 2 [univariate hazard ratio: 5.20; P = 0.033]. Similarly, group 2 showed elevated overall mortality [univariate hazard ratio: 5.18; P < 0.001]. AFS at 1 and 2 years were 67.9% and 55%, respectively, with higher rates in group 1. Wound healing was achieved in 76.1% of patients (83/109), with frailty significantly associated with delayed wound healing (P < 0.001). Vessel patency at 1 year was observed in 88.8% of patients. HRQoL significantly improved postintervention, with vascular quality of life questionnaire-6 (VascuQol-6) scores increasing from an average of 9 of 24 at baseline to 20 of 24 at 2 years. Frailty score significantly correlated with VascuQol-6 scores at 1 and 2 years (P < 0.0012). Group 1 exhibited higher VascuQol-6 scores than group 2, indicating improved HRQoL during follow-up.

CONCLUSIONS

Successful endovascular treatments in high-risk CLTI patients promote improved wound healing and post-treatment quality of life. Frailty should be assessed before endovascular interventions as it correlates with adverse outcomes, including amputations and mortality. While revascularization holds promise, caution is advised for frailer patients, emphasizing the importance of personalized care and tailored treatments for elderly CLTI patients.

Validation of the global limb anatomical staging system in Vietnamese patients treated for chronic limb-threatening ischemia

BACKGROUND

Chronic limb-threatening ischemia (CLTI) is the most severe clinical form of peripheral artery disease (PAD), accounting for approximately 11%, and is strongly associated with the incidence of amputation, cardiovascular events, and mortality. The Global Vascular Guideline (GVG) proposed a new Global Anatomic Staging System (GLASS) for evaluating the anatomic complexity of arterial lesions. However, more research is required to evaluate outcomes after endovascular intervention in CLTI patients using the GLASS.

OBJECTIVE

Our study aimed to describe clinical characteristics, arterial lesions, and endovascular interventions according to three grades of GLASS in the Vietnamese population. We evaluated the technical success, mortality rate, and probability to preserve the limb according to the GLASS.

METHODS

All patients were diagnosed with CLTI and underwent infrainguinal endovascular intervention at the Department of Thoracic and Vascular Surgery, University Medical Center, Ho Chi Minh City from June 2020 to June 2022. All patients were evaluated before intervention and follow-up at 6 and 12 months after intervention. Patients were divided into three groups according to the GLASS, thereby comparing the technical success, mortality, and amputation rates. This retrospective study describes a series of cases.

RESULTS

The study sample evaluated 82 lower limbs of 82 patients, in which GLASS class I, II, and III lesions accounted for 36.6%, 43.9%, and 19.5% of the patients, respectively. The rates of technical success in the groups gradually decreased according to the complexity of the lesions (90%, 86.11%, and 56.25% for GLASS I, II, and III, respectively; p = 0.012). Notably, limb-based patency (LBP) at 12 months was significantly lower in the GLASS III group than in the GLASS I and II groups (22.22% vs 88.89% and 67.74%, respectively; p = 0.001). The amputation rates at 12 months in GLASS groups I, II, and III were 13.3%, 22.2%, and 50%, respectively (p = 0.021), while the mortality rates at 12 months were 0%, 8.33%, and 25%, respectively (p = 0.015).

CONCLUSION

In patients with CLTI of higher GLASS stages, the rates of technical success were lower and the amputation and mortality rates were higher.

Editor's Choice - Infra-inguinal Endovascular Revascularisation and Bypass Surgery for Chronic Limb Threatening Ischaemia: a Retrospective European Multicentre Cohort Study with Propensity Score Matching

OBJECTIVE

The aim of this study was to compare the long term efficacy of lower limb bypass with that of endovascular treatment (EVT) in patients with chronic limb threatening ischaemia (CLTI).

METHODS

This retrospective, multicentre study evaluated the outcomes of patients with CLTI who underwent first time infra-inguinal bypass or EVT. The primary outcome was to compare amputation free survival (AFS) rates between the two propensity score matched groups. The secondary outcome was to compare wound healing within the first six months. Major adverse events were compared according to the type of revascularisation.

RESULTS

Overall, 793 patients fulfilled the eligibility criteria, from whom 236 propensity score matched pairs were analysed. The mean follow up was 52 months. The 236 bypass procedures included 190 autogenous bypass grafts (80.5%), 151 (64.0%) of which were infrapopliteal. Among the 236 EVT procedures, the target lesion was the femoropopliteal segment in 81 patients (34.3%), the femoropopliteal and infrapopliteal segments in 101 patients (42.8%), and the infrapopliteal segment in 54 patients (22.9%). AFS was significantly better in the bypass group at five years (60.5 ± 3.6%) compared with the EVT group (35.3 ± 3.6%) (p < .001). Major amputation occurred in 61 patients (25.8%) in the bypass group and 85 patients (36.0%) in the EVT group (HR 0.66, 95% CI 0.47 - 0.92; p = .014). The probability of healing was significantly better in the bypass group at six months compared with the EVT group (p = .003). The median length of stay was shorter for the EVT group (4 days) than for the bypass group (8 days) (p = .001). Urgent re-intervention and re-admission rates were high and did not differ significantly between the groups.

CONCLUSION

This study has shown that lower limb bypass surgery offered a significantly higher probability of AFS and wound healing compared with EVT in patients with CLTI.

Validity of the Global Vascular Guidelines in Predicting Outcomes Based on First-Time Revascularization Strategy

BACKGROUND

The Global Vascular Guidelines (GVG) recommend selecting an endovascular versus open-surgical approach to revascularization for chronic limb-threatening ischemia (CLTI), based on the Global Limb Anatomic Staging System (GLASS) and wound, ischemia, and foot infection (WIfI) classification systems. We assessed the utility of GVG-recommended strategies in predicting clinical outcomes.

METHODS

We conducted a single-center, retrospective review of first-time lower-extremity revascularizations within a comprehensive limb-preservation program from 2010 to 2018. Procedures were stratified by (1) treatment concordance with GVG-recommended strategy (concordant versus nonconcordant groups), (2) GLASS stages I-III, and (3) endovascular versus open strategies. The primary outcome was 5-year freedom from major adverse limb events (FF-MALE), defined as freedom from reintervention or major amputation, and secondary outcomes included 5-year overall survival, freedom from major amputation, freedom from reintervention, and immediate technical failure (ITF) during initial revascularization. Kaplan-Meier (KM) survival analysis and multivariate analysis with Cox proportional hazard models were performed on the primary and secondary outcomes.

RESULTS

Of 281 first-time revascularizations for CLTI, 251 (89.3%) were endovascular and 186 (66.2%) were in the concordant group, with a mean clinical follow-up of 3.02 ± 2.40 years. Within the concordant group alone, 167 (89.8%) of revascularizations were endovascular. The concordant group had a higher rate of chronic kidney disease (60.8% vs. 45.3%, P = 0.02), WIfI foot infection grade (0.81 ± 1.1 vs. 0.56 ± 0.80, P = 0.03), and WIfI stage (3.1 ± 0.79 vs. 2.8 ± 1.2, P < 0.01) compared to the non-concordant group. After both KM and multivariate analyses, there were no significant differences in 5-year FF-MALE or overall survival between concordant and non-concordant groups. There was higher freedom from major amputation in the non-concordant group on KM analysis (83.9% vs. 74.2%, P = 0.025), though this difference was non-significant on multivariate analysis (hazard ratio [HR]: 0.49, 95% confidence interval [CI]: 0.21-1.15, P = 0.10). The open group had lower MALE compared to the endovascular group (HR: 0.39, 95% CI: 0.17-0.91, P = 0.029) attributed to a lower reintervention rate in the open group (HR: 0.31, 95% CI: 0.11-0.87, P = 0.026). GLASS stage was not associated with significant differences in outcomes, but the severity of GLASS stage was associated with ITF (2.1% in stage 1, 6.4% in stage 2, and 11.7% in stage 3, P = 0.01).

CONCLUSIONS

In this study, CLTI treatment outcomes did not differ significantly based on whether treatment was received in concordance with GVG-recommended strategy. There was no difference in overall survival between the endovascular and open groups, though there was a higher reintervention rate in the endovascular group. The GVG guidelines are an important resource to help guide the management of CLTI patients. However, in this study, both concordance with GVG guidelines and GLASS staging were found to be indeterminate in differentiating outcomes between complex CLTI patients treated primarily with an endovascular-first approach. The revascularization approach for a CLTI patient is a nuanced decision that must take into account patient anatomy and clinical status, as well as physician skill and experience and institutional resources.

Utility and safety of a novel method using a Wingman catheter for patients with lower extremity arterial disease complicated with severely calcified lesions: Wingman's bevel tip inner catheter removal technique-A prospective cohort study

Background and Aims

In cases of lower extremity artery disease (LEAD) accompanied by heavily calcified lesions, endovascular treatment becomes necessary at times. To effectively address these challenging calcified lesions, we developed an innovative approach named WINNER (Wingman's bevel tip inner catheter removal) technique. This study investigated the effectiveness and safety of a novel method using the WINNER technique.

Methods

This was a two-center, prospective observational study. We analyzed the clinical data of patients with LEAD complicated with severely calcified lesions who underwent the WINNER technique between January 2021 and December 2022. We investigated the patients' characteristics, target lesions, and intervention results in terms of crossing device rates and periprocedural complications.

Results

A total of 35 patients were treated using the WINNER technique for LEAD complicated by severely calcified lesions. Key patient characteristics were a mean age of 75 ± 9 years, 83% male, 71% hemodialysis, 60% chronic limb-threatening ischemia, and mean lesion length of 147 ± 88 mm. Using the WINNER technique, a device crossing was achieved in 34 patients (97.1%). Wire perforation occurred in one patient, and WINNER catheter rupture occurred in three patients.

Conclusions

The WINNER technique is useful for treating severely calcified lesions, and we should consider using this technique to cross devices for lesions with severe calcifications.

A systematic review and meta-analysis of GLASS staging system in the endovascular treatment of chronic limb-threatening ischemia

OBJECTIVE

The objective of this study was to evaluate the application of the Global Anatomic Staging System (GLASS) in the endovascular treatment of chronic limb-threatening ischemia (CLTI).

METHODS

We performed systematic research between June 2019 and February 2022, including articles investigating the relationship of GLASS classification with the outcomes of endovascular interventions in the treatment of CLTI. Data from the included studies were pooled and meta-analyzed. The primary endpoints were limb-based patency (LBP) at 1-year follow-up and immediate technical failure (ITF). Secondary endpoints included major amputation. We performed subgroup analysis between studies that reported on calcium modifier inclusion during GLASS classification and studies that did not.

RESULTS

Eleven studies, including 1816 patients (1975 limbs) met the inclusion criteria. The pooled ITF rates for GLASS stages I, II, and III are 5.52% (95% confidence interval [CI], 3.74%-8.07%), 7.39% (95% CI, 5.32%-10.18%), and 21.07% (95% CI, 13.48%-31.39%) respectively. The pooled LBP for GLASS stages I, II, and III are 68.43% (95% CI, 53.44%-80.37%), 41.52% (95% CI, 18.91%-68.37%), and 38.64% (95% CI, 19.83%-61.57%). The relative risk (RR) for ITF regarding composite GLASS I and II stages vs GLASS III is 3.96 (95% CI, 1.96-7.98). The RR for LBP of GLASS I and II versus GLASS stage III is 1.51 (95% CI, 0.86-2.64). Pooled major amputation rates for the composite GLASS I, II and GLASS III stages are 7.62% (95% CI, 5.44%-10.58%) and 15.43% (95% CI, 11.72%-20.05%) respectively, whereas the RR between GLASS I, II, and GLASS III stages is 1.84 (95% CI, 1.18-2.87).

CONCLUSIONS

Our study demonstrated that patients with CLTI undergoing endovascular interventions classified as GLASS stage III had almost a four-fold risk increase for ITF and 1.84 times the risk of major amputation compared with stages I and II. Additionally, GLASS classification correctly predicted ITF for all three stages, whereas it failed to predict stage I and II LBP outcomes. Safe conclusions regarding LBP cannot be drawn due to the low quality and small number of the included studies, necessitating further research. Furthermore, we displayed the importance of calcium moderator inclusion in the accurate classification of GLASS.

Global Limb Anatomic Staging System Inframalleolar Modifier Predicts Limb Salvage and Wound Healing in Patients with Chronic Limb Threatening Ischaemia Undergoing Endovascular Infrainguinal Revascularisation

OBJECTIVE

This study aimed to analyse the influence of the Global Anatomic Staging System (GLASS) and inframalleolar (IM) disease on the treatment outcomes of patients with chronic limb threatening ischaemia (CLTI) who undergo endovascular treatment (EVT) METHODS: Data of patients who underwent infrainguinal endovascular therapy (EVT) for CLTI between 2015 and 2019 at two centres were analysed retrospectively. The endpoints were major amputation, major adverse limb events (MALE), and wound healing.

RESULTS

Overall, 276 patients and 340 limbs were analysed. The number of revascularisations for an infrapopliteal lesion was 48 (70.6%), 63 (63.0%), and 142 (82.6%) in the GLASS I, GLASS II, and GLASS III stages, respectively (p < .001). There was no statistically significant difference in limb salvage among the GLASS stages (p = .78). The limb salvage rates at one year were 94.6%, 88.0%, and 70.0% in the IM P0 P1, and P2 groups, respectively (p < .001). Multivariable analysis showed that Wound, Ischemia, and foot Infection (WIfI) stage, and IM grade were risk factors for major amputation. The freedom from MALE rates at two years were 60.5%, 45.3%, and 41.1% in the GLASS I, II, and III stages, respectively (p = .003) and 64.1%, 43.5%, and 18.4% in the IM P0, P1, and P2 groups, respectively (p < .001). Multivariable analysis demonstrated that WIfI stage, GLASS stage, IM grade, and infrapopliteal revascularisation were risk factors for MALE. There was no significant difference in wound healing among GLASS I - III (p = .75). The wound healing rates at 365 days were 78.6%, 68.6%, and 42.0% in the IM P0, P1, and P2 groups, respectively (p = .065). Multivariable analysis showed that WIfI stage and IM P2 were risk factors for incomplete wound healing.

CONCLUSION

GLASS IM was associated with major amputation, MALE, and wound healing, while GLASS stage was associated with only MALE.

Evaluation of the Global Limb Anatomic Staging System in patients with chronic limb-threatening ischemia undergoing endovascular intervention for femoropopliteal disease

BACKGROUND

The Global Limb Anatomic Staging System (GLASS) is a new method of quantifying the anatomic severity of infrainguinal disease in patients with chronic limb-threatening ischemia. However, because GLASS has undergone limited validation, its value as an aid to shared decision-making regarding the choice of revascularization strategy remains incompletely defined. Here we report the relationship between GLASS and outcomes in a contemporary series comprising all 309 patients who underwent an attempt at femoropopliteal and/or infrapopiteal endovascular therapy for chronic limb-threatening ischemia in our unit between 2009 and 2014.

METHODS

Baseline patient characteristics and outcome data including immediate technical success (ITS), amputation-free survival (AFS), overall survival, limb salvage, freedom from reintervention (FF-R), and freedom from major adverse limb events (FF-MALE) were obtained from hospital databases. GLASS grades and stage were obtained from pre-endovascular therapy angiographic imaging. Outcome data were censored on May 31, 2017.

RESULTS

Baseline patient characteristics were similar across different GLASS femoropopliteal and IP grades and overall limb stages. Worsening GLASS stage was associated with a significant reduction in ITS (97.5% vs 91.5% vs 84.0%; P = .029). At 72 months FF-R (hazard ratio, 2.00; 95% confidence interval, 1.11-3.57; P = .020) and FF-MALE (hazard ratio, 1.76, 95% confidence interval, 1.10-2.81; P = .019) were significant worse in GLASS stage 3 than in stage 2 limbs.

CONCLUSIONS

In our study, there were significant differences in ITS, FF-R and FF-MALE between limbs with GLASS stage 2 and 3 disease. However, further GLASS refinement seems likely to be required if its usefulness in everyday clinical practice as an aid to shared decision-making regarding the choice of revascularization strategy is to be maximized.

High Global Limb Anatomic Staging System Femoropopliteal Grade is Positively Associated with Wound Healing in Patients with Chronic Limb-Threatening Ischemia Undergoing Endovascular Therapy Only for Femoropopliteal Disease

BACKGROUND

To investigate the prognostic impact of femoropopliteal (FP) arterial anatomic severity including classification by the global limb anatomic staging system (GLASS) on wound healing in patients with chronic limb-threatening ischemia (CLTI) who had undergone endovascular therapy (EVT) only for FP lesions.

METHODS

This was a retrospective single-center study. We treated 349 consecutive de novo CLTI limbs with tissue loss from January 2017 to May 2021. Among these, 91 limbs treated via EVT only for FP lesions were enrolled. We compared the clinical background, infrapopliteal (IP)/FP arterial anatomical characteristics, and EVT results between the limbs with GLASS FP grade 1 or 2 (low GLASS FP, n = 20) and those with GLASS FP grade 3 or 4 (high GLASS FP, n = 71). The Kaplan-Meier method was used to estimate the wound healing rate. The Cox proportional hazard model was used to assess the association between baseline characteristics and wound healing.

RESULTS

No patient underwent EVT for IP lesions. IP arterial anatomical characteristics did not show any significant difference between the low and high GLASS FP groups. The cumulative wound healing rate after EVT was significantly higher in the high GLASS FP group than in the low GLASS FP group (88% vs. 39% at 6 months; P < 0.001). Multivariate analysis revealed that low wound, ischemia, and foot infection (WIfI) clinical stage (stage 1 or 2) (hazard ratio [HR] 2.33; 95% confidence interval [CI] 1.32-4.17) and high GLASS FP (grade 3 or 4) (HR 5.18; 95% CI 1.99-13.51) were independent factors for wound healing.

CONCLUSIONS

High GLASS FP grade was positively associated with wound healing after EVT only for FP lesions.

Predictive impact of the Global Limb Anatomic Staging System (GLASS) on perioperative outcomes in patients with chronic limb-threatening ischaemia with isolated below-the-knee lesions

Although the global vascular guidelines recently proposed the Global Limb Anatomic Staging System (GLASS) as an anatomical classification for chronic limb-threatening ischaemia (CLTI), prediction of perioperative outcomes using the GLASS classification in patients with CLTI due to isolated below-the-knee (BTK) lesions has not been well studied.This retrospective study included 585 patients with CLTI due to isolated BTK lesions who underwent endovascular therapy (EVT). The severity of arterial lesions was graded using the GLASS infrapopliteal (IP) and inframalleolar (IM) classifications and defined as follows: non-severe IP, 0-3; severe IP, 4; non-severe IM, P0-1; and severe IM, P2. The outcome measures were technical failure, defined as recanalisation failure of the target artery path, and perioperative failure, defined as a composite of all-cause death, major amputation, or repeat revascularisation within 30 days.Technical and perioperative failures occurred in 9.4% (n = 55) and 9.9% (n = 58) patients, respectively. Compared to patients with non-severe IP and IM, those with both severe IP and IM were significantly associated with technical and perioperative failures (odds ratio [OR]: 13.87 [95% confidence interval (CI) 4.69-41.02, P < 0.001] and OR: 2.18 [95% CI 1.08-4.38, P = 0.041], respectively).The GLASS classification may have predictive value for technical and perioperative failure in patients with CLTI due to isolated BTK lesions after EVT.

Prediction of 2-Year Major Adverse Limb Event-Free Survival After Percutaneous Transluminal Angioplasty and Stenting for Lower Limb Atherosclerosis Obliterans: A Machine Learning-Based Study

Background

The current scoring systems could not predict prognosis after endovascular therapy for peripheral artery disease. Machine learning could make predictions for future events by learning a specific pattern from existing data. This study aimed to demonstrate machine learning could make an accurate prediction for 2-year major adverse limb event-free survival (MFS) after percutaneous transluminal angioplasty (PTA) and stenting for lower limb atherosclerosis obliterans (ASO).

Methods

A lower limb ASO cohort of 392 patients who received PTA and stenting was split to the training set and test set by 4:1 in chronological order. Demographic, medical, and imaging data were used to build machine learning models to predict 2-year MFS. The discrimination and calibration of artificial neural network (ANN) and random forest models were compared with the logistic regression model, using the area under the receiver operating curve (ROCAUC) with DeLong test, and the calibration curve with Hosmer–Lemeshow goodness-of-fit test, respectively.

Results

The ANN model (ROCAUC = 0.80, 95% CI: 0.68–0.89) but not the random forest model (ROCAUC = 0.78, 95% CI: 0.66–0.87) significantly outperformed the logistic regression model (ROCAUC = 0.73, 95% CI: 0.60–0.83, P = 0.01 and P = 0.24). The ANN model the logistic regression model demonstrated good calibration performance (P = 0.73 and P = 0.28), while the random forest model showed poor calibration (P < 0.01). The calibration curve of the ANN model was visually the closest to the perfectly calibrated line.

Conclusion

Machine learning models could accurately predict 2-year MFS after PTA and stenting for lower limb ASO, in which the ANN model had better discrimination and calibration. Machine learning-derived prediction tools might be clinically useful to automatically identify candidates for PTA and stenting.

Validation of the correlation between angiosome-based target arterial path, mid-term limb-based patency, and the global limb anatomical staging system

This study aimed to validate the correlation between the Global Limb Anatomical Staging System (GLASS) and limb-based patency (LBP) and angiosome-based target arterial path (TAP) and to detect the predictors of LBP loss. After the publication of the Global Vascular Guidelines in 2019, the evaluation of GLASS and identification of TAP have been recommended. However, there are few reports regarding GLASS. Eighty-three patients with chronic limb-threatening ischemia (CLTI) and tissue loss from 2016 to 2020 were evaluated. The correlation between GLASS and LBP and successful revascularization of angiosome-based TAP was analyzed. We also investigated the predictors of LBP loss. The number of patients in each GLASS stage was as follows: GLASS I, 6 patients; GLASS II, 15 patients; GLASS III, 62 patients. At 6 months, the Kaplan-Meier estimate of LBP was 66.7% in GLASS I, 41.6% in GLASS II, and 16.4% in GLASS III, respectively (p = 0.034). The rate of successful revascularization of angiosome-based TAP was 100% in GLASS I, 86.7% in GLASS II, and 46.8% in GLASS III, respectively (p = 0.002). Multivariate analysis showed that the Wound, Ischemia, and foot Infection (WIfI) stage [hazard ratio (HR) 1.58; 95% confidence interval (CI) 1.07-2.33; p = 0.021] and GLASS infrapopliteal (IP) grade (HR 1.96; 95% CI 1.31-2.95; p = 0.001) were the independent predictors of LBP loss. The GLASS stage was significantly correlated with successful revascularization of angiosome-based TAP and mid-term LBP. The WIfI stage and GLASS IP grade were the independent predictors of loss of LBP.

The Global Anatomic Staging System Does Not Predict Limb Based Patency of Tibial Endovascular Interventions

OBJECTIVE

Anatomic grading systems have historically been poor predictors of patency after endovascular tibial interventions. The Global Vascular Guidelines proposed a new Global Anatomic Staging System (GLASS) to estimate one-year limb-based patency (LBP). The purpose of this study was to determine the association of GLASS with LBP following endovascular tibial interventions.

METHODS

We included all patients presenting to our multidisciplinary diabetic limb preservation service between 01/2012 and 8/2020 who underwent first-time endovascular tibial revascularization for chronic limb-threatening ischemia. Diagnostic angiograms were reviewed to define the preferred target artery pathway and assign a GLASS stage to each treated limb. One-year LBP was calculated and compared across GLASS stages using Kaplan-Meier curves with log-rank tests and Cox proportional hazards models.

RESULTS

We performed tibial revascularization in 96 limbs (5.2% rest pain, 56.3% ulcer, 37.5% gangrene), including isolated tibial interventions in 61.5% and tibial + femoropopliteal interventions in 38.5%. 15.6% of limbs were GLASS stage 1, 28.1% were GLASS stage 2, and 56.3% were GLASS stage 3. Overall, one-year LBP was 43.2 ± 6.3%, and did not differ significantly across GLASS stages (P = 0.42). The hazard ratio for failed LBP was 1.94 (95% CI 0.70-5.41) for GLASS stage 2 and 1.49 (95% CI 0.56-3.94) for GLASS stage 3 limbs (versus GLASS stage 1). When analyzed excluding the calcium modifier, LBP remained similar across GLASS stages (P = 0.72). Major amputation was uncommon, occurring in 9.3 ± 3.4% of limbs at one year, and did not significantly differ by GLASS stage (P = 0.98).

CONCLUSION

The Global Anatomic Staging System did not predict limb-based patency following tibial endovascular interventions. Given the low major amputation rates in this cohort, anatomic complexity should not preclude endovascular limb salvage efforts below the knee.

Early evaluation of the infrainguinal revascularization strategy selection tool of the Global Vascular Guidelines for chronic limb-threatening ischemia patients

OBJECTIVE

The Global Vascular Guidelines (GVG) propose a novel Global Anatomic Staging System (GLASS) with the Wound, Ischemia, and foot Infection (WIfI) classification system as a clinical decision-making tool for interventions in chronic limb-threatening ischemia (CLTI). We assessed the validity of clinical staging and the relationship between the treatments recommended by the GVG and the outcomes of the actual procedures.

METHODS

This retrospective, single-center, observational study included 117 patients with CLTI undergoing infrainguinal revascularization in our hospital between 2015 and 2019. Of those patients, 55 underwent open bypass (OB) and 62 underwent endovascular revascularization (EVR). Femoropopliteal, infrapopliteal, and inframalleolar GLASS grades were assigned based on angiographic images. These grades were combined to determine the revascularization strategy recommended by the GVG: "endovascular," "indeterminate," and "open bypass." The indeterminate category includes three subcategories: GLASS stage III, WIfI stage 2; GLASS stage II, WIfI stage 3; and GLASS stage II, WIfI stage 4. For the purposes of this study, we labeled these subcategories A, B, and C, respectively. The primary outcome was the correlation between the revascularization strategies recommended by the GVG and the actual procedures performed. The relationships between the actual procedures and overall survival, limb salvage, and patency were also examined.

RESULTS

The femoropopliteal and infrapopliteal GLASS grades were higher in the OB group. EVR was performed more often for GLASS stages I and II and was more often classified as indeterminate B and C, whereas OB was performed more often in GLASS stage III and was more often classified as indeterminate A. There were no statistically significant differences in the inframalleolar/pedal disease descriptor or in the 30-day postoperative complication rates between the two groups. In higher GLASS stages, the technical success rate of EVR was lower, and lesion complexity was more severe. Patients for whom the recommended strategy according to the GVG would have been OB but who underwent EVR were associated with low limb salvage and patency rates.

CONCLUSIONS

The GVG provide good guidance for the selection of the revascularization strategy. When the GVG indicate OB, it should be the treatment of choice, rather than EVR, for patients who are fit to undergo the procedure.

Successful Peripheral Vascular Intervention in Patients with High-risk Comorbidities or Lesion Characteristics

PURPOSE OF REVIEW

Certain comorbidities and lesion characteristics are associated with increased risk for procedural complications, limb events, and cardiovascular events following peripheral vascular intervention (PVI) in patients with peripheral arterial disease (PAD). The purpose of this review is to provide an overview of high-risk modifiable and unmodifiable patient characteristics and its relative impact on clinical outcomes such as amputation risk and mortality. Furthermore, general approaches to potentially mitigating these risks through pre-intervention planning and use of modern devices and techniques are discussed.

RECENT FINDINGS

Diabetes, tobacco use, and older age remain strong risk factors for the development of peripheral arterial disease. Recent data highlight the significant risk of polyvascular disease on major limb and cardiac events in advanced PAD, and ongoing studies are assessing this risk specifically after PVI. Challenging lesion characteristics such as calcified disease and chronic total occlusions can be successfully treated with PVI by utilizing novel devices (e.g., intravascular lithotripsy, re-entry devices) and techniques (e.g., subintimal arterial "flossing" with antegrade-retrograde intervention). Understanding high-risk patient comorbidities and lesion characteristics will improve our ability to counsel and manage patients with advanced PAD. Continued device innovation and novel techniques will aid in procedural planning for successful interventions to improve clinical outcomes.

Validation of Global Limb Anatomical Staging System (GLASS) in patients with hemodialysis and Chronic Limb-Threatening Ischemia after endovascular treatment

Recently, Society for Vascular Surgery guideline recommends evaluating anatomic pattern with use of Global Limb Anatomic Staging System (GLASS) in Chronic Limb-Threatening Ischemia (CLTI) patients. The aim of this study is to validate GLASS stage into CLTI patients on hemodialysis (HD) and investigate the impact of GLASS stage to wound healing and amputation-free survival (AFS). Between April 2009 and March 2018, we performed EVT for 154 limbs in CLTI patients on HD. GLASS was defined as femoropopliteal (FP) and infrapopliteal (IP) segments separately graded (0-4), then combined into three GLASS stages for the limb (I-III). We divided them into three GLASS stages with using this system. We compared the clinical outcomes between three groups (GLASS I, GLASS II, and GLASS III). Patient characteristics were almost similar between the three groups. Lesion characteristics was more complex and the rate of success was lower in GLASS III. Cox regression multivariate analysis revealed that diabetes mellitus (HR 2.4, 95% CI 1.37-4.01, p < 0.01) and WIfI high (HR 2.3, 95% CI 1.04-6.01, p = 0.04) were the predictors of non-wound healing, whereas age (HR 1.6, 95% CI 1.09-2.29, p = 0.01), WIfI clinical stage 4 (HR 2.4, 95% CI 1.30-4.36, p < 0.01), and non-ambulatory status (HR 2.0, 95% CI 1.17-3.29, p = 0.01) were the predictors of AFS. GLASS stage in CLTI patient on HD could not predict wound healing, and AFS in this study.

Skeletal Muscle Mitochondrial Dysfunction and Oxidative Stress in Peripheral Arterial Disease: A Unifying Mechanism and Therapeutic Target

Peripheral artery disease (PAD) is caused by atherosclerosis in the lower extremities, which leads to a spectrum of life-altering symptomatology, including claudication, ischemic rest pain, and gangrene requiring limb amputation. Current treatments for PAD are focused primarily on re-establishing blood flow to the ischemic tissue, implying that blood flow is the decisive factor that determines whether or not the tissue survives. Unfortunately, failure rates of endovascular and revascularization procedures remain unacceptably high and numerous cell- and gene-based vascular therapies have failed to demonstrate efficacy in clinical trials. The low success of vascular-focused therapies implies that non-vascular tissues, such as skeletal muscle and oxidative stress, may substantially contribute to PAD pathobiology. Clues toward the importance of skeletal muscle in PAD pathobiology stem from clinical observations that muscle function is a strong predictor of mortality. Mitochondrial impairments in muscle have been documented in PAD patients, although its potential role in clinical pathology is incompletely understood. In this review, we discuss the underlying mechanisms causing mitochondrial dysfunction in ischemic skeletal muscle, including causal evidence in rodent studies, and highlight emerging mitochondrial-targeted therapies that have potential to improve PAD outcomes. Particularly, we will analyze literature data on reactive oxygen species production and potential counteracting endogenous and exogenous antioxidants.