Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) and the (hoped for) dawn of evidence-based treatment for advanced limb ischemia

Understanding the Pain Experience and Treatment Considerations Along the Spectrum of Peripheral Artery Disease: A Scientific Statement From the American Heart Association

Peripheral artery disease (PAD) is an atherosclerotic condition that affects a growing number of individuals worldwide, with estimates exceeding 220 million. One of the central hallmarks of PAD is lower extremity pain, which may present as intermittent claudication and atypical leg pain, and, in more severe cases, ischemic rest pain, neuropathic pain, or phantom limb pain in those who underwent amputation. Although the majority of individuals with PAD may experience pain that is chronic in nature, the pathogenesis and phenomenology of pain may differ. Nociceptive, inflammatory, and neuropathic mechanisms all play a role in the generation of pain. Pain in PAD results in severe disability and can copresent with distress, sickness behaviors such as avoidance and further deconditioning, and concomitant depression, anxiety, and addiction secondary to opioid use. These factors potentially lead to chronic pain interacting with a multitude of domains of functioning, including physical, emotional, and behavioral. Whereas pain is a normal adaptive response, self-defeating behaviors and cognitions contribute to the persistence or worsening of the chronic pain experience, disability, and distress. Much remains unknown about the phenomenology of pain in PAD and its clinical subgroups and how it affects outcomes. Borrowing from other chronic pain syndromes, multimodal pain management strategies that emphasize a biopsychosocial model have generated a solid evidence base for the use of cognitive behavioral approaches to manage pain. Multimodal pain management in PAD is not the norm, but theoretical pathways and road maps for further research, assessment, and clinical implementation are presented in this scientific statement.

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 (PDB) or tibial angioplasty (TA), 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 TA in patients with CLTI.

METHODS

Patients who underwent PDB 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 TA were identified in the targeted lower extremity endovascular database. Any case with more proximal angioplasty such as femoral/popliteal/iliac was excluded. The time interval was 2011 through 2022. The two groups were comparable in demographics, and preoperative 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 PDB or TA, The George Washington University institutional data from 2014 to 2019 was used as a supplement to the database.

RESULTS

There were 1947 and 3423 cases identified in the bypass and endovascular groups, respectively. After propensity matching for all preoperative variables, 1747 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 with TA (major amputation rate, 3.32% vs 6.12%; P < .01). Institutional data identified 69 patients with CLTI due to isolated tibial occlusive disease; 25 (36.2%) underwent PDB and 44 (63.8%) underwent TA. Review of angiographic details revealed patients who underwent PDB had better pedal targets (inframalleolar/pedal score of P0 [24.0% vs 15.9%] or P1 [68.0% vs 61.3%]) than TA patients (inframalleolar/pedal score of P2 [22.7% vs 8.0%]).

CONCLUSIONS

PDB 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 PDB and TA in cases with similar pedal targets.

A systematic review of simulation training for lower extremity bypass procedures

OBJECTIVES

Simulation is used across surgical specialties for skill enhancement. The choice and assessment method of a simulator varies across literature. In the age of endovascular approach, trainees have limited exposure to open lower limb bypass procedures which needs attention. This review aims to assess the utility of simulation training in lower limb bypass surgery using Kirkpatrick's model.

METHODS

Using PRISMA statement, we included all the studies done on simulators in lower limb bypass surgical procedures for this systematic review. The primary outcome was to assess the effectiveness of different types of simulation used for lower limb bypass surgery using the Kirkpatrick's model for training evaluation.

RESULTS

An initial search identified 295 articles out of which 7 articles were found to be eligible for this systematic review. A variety of simulators were used including cadavers and synthetic models. Most studies (n=5) found the use of simulation as an effective tool in achieving technical competence. All the five studies we found at level 2 on Kirpatrick's model evaluation.

CONCLUSION

Most of the existing studies are at level 2 of Kirkpatrick's model which reflects learning changes in trainees after simulation. Feedback mechanism needs to be evolved where the improvement after simulation training can be gauged by its replication in clinical practice and improved patient care practices corresponding to the highest level of Kirkpatrick's model.

Effects of L-Ornithine-L-Aspartate on Angiogenesis and Perfusion in Subacute Hind Limb Ischemia: Preliminary Study

The current treatment options for peripheral arterial disease (PAD) are limited due to a lack of significant high-level evidence to inform clinical decisions and unfavorable outcomes in terms of cost-effectiveness and amputation rates. In order to suggest the use of the commercially available L-Ornithine-L-Aspartate (LOLA) for treating PAD, we induced hind limb ischemia (HLI) by unilaterally ligating the femoral artery in a rat model. The rats were randomly divided into three groups, with seven rats assigned to each group: group 1 (control), group 2 (sorbitol), and group 3 (LOLA). Intraperitoneal injections were administered five times on post-operative days (PODs) 3, 5, 7, 10, and 12. Perfusion imaging was conducted on PODs 7 and 14 and compared to pre-operative perfusion imaging. Immunohistochemistry staining and Western blotting were performed after the final perfusion imaging. Group 3 showed a significant increase in perfusion, high CD31-positive capillary lumen density, and substantial overexpression of VEGF in the ischemic limb during the subacute phase of HLI. In conclusion, this study provides the first documented evidence of angiogenesis and perfusion recovery in the subacute phase of the HLI model following the administration of LOLA. With LOLA readily available on the commercial market, the implementation of LOLA treatment for PAD in humans can be expedited compared to other therapies still in the developmental stage.

Prospective Comparison of Wound Complication Rates after Elective Open Peripheral Vascular Surgery - Endovascular Versus Open Vascular Surgeons

BACKGROUND

Skill and experience of surgeons are likely to influence the incidence of surgical wound complications (SWC) after open lower limb revascularization. Differences in SWC between surgeons with predominantly endovascular or open vascular surgical profiles could be expected. The aim of this study was to compare SWC rates after elective open vascular surgery between primarily endovascular and primarily open vascular surgeons.

METHODS

Prospective data from patients undergoing elective surgery for peripheral artery disease (PAD) was collected between 2013 and 2019. Senior surgeons were assigned to the open-surgeon or the endo-surgeon group based on the percentage of their open surgical case load during the 6 year study period. SWC was measured by their clinical impact scale (grade 1-outpatient treatment to grade 6-death). Surgical site infection was defined by Additional treatment, Serous discharge, Erythema, Purulent exudate, Separation of deep tissues, Isolation of bacteria, and Stay (ASEPSIS) criteria. Propensity score adjusted analysis (PSAA) was used to account for differences in baseline and perioperative characteristics and expressed as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

The proportion of chronic limb-threatening ischemia (P = 0.001), ipsilateral foot wound (P = 0.012) and femoro-popliteal bypass procedures (P < 0.001) were higher in the open-surgeon group. A lower incidence of SWC according to ASEPSIS criteria (25.6% vs. 38.6%, respectively, P = 0.042) and SWC grade ≥1 (33.7% vs. 51.0%, respectively, P = 0.010) was found in the endo-surgeon group (n = 86) compared to the open-surgeon group (n = 153). These differences disappeared after PSAA (OR 0.63, 95% CI 0.27-1.44, and OR 0.60, 95% CI 0.27-1.33, respectively).

CONCLUSIONS

Patients operated by endo-surgeons had less advanced PAD and lower incidence of SWC compared to those treated by open-surgeons. No difference in SWC remained after PSAA.

THE EFFECTIVENESS OF XENO-PERICARDIAL PATCH IN REVASCULARIZATION OF AN ISCHEMIC LIMB USING THE DEEP FEMORAL ARTERY

Highlights

The choice of method for revascularization of the ischemic lower limb remains an important issue in cardiovascular surgery. Of the available methods, the most effective, in our opinion, is revascularization of the limb using the deep femoral artery. In this case, it is necessary to carefully select the material for the expanding patch, which prevents the development of restenosis.

 

Abstract

Aim. To compare the effectiveness of autovenous and xeno-pericardial patches in revascularization of an ischemic limb using a deep femoral artery.

Methods. An analysis of the comprehensive examination and treatment of 30 patients with critical ischemia, who were divided into 2 statistically homogeneous groups of 15 people each, was carried out.  In the first group, an autovenous patch was used to repair the deep femoral artery, and in the second group, a xeno-pericardial patch was used. The short-term results of treatment were assessed by the number of postoperative complications, ankle brachial index and the clinical picture of the disease 1 month after surgery, whereas the long-term results were assessed by the deep femoral artery patency and the quality of life of patients.

Results. 6 complications of the same type were registered in 4 (13.3%) patients, two in each group. After 1 month, the ankle brachial index in the first group was 0.58±0.12, and in the second 0.61±0.13. All patients in both groups had relief of pain at rest, an increase in pain-free walking distance, and trophic disorders healed. After 5 years, the deep femoral artery in the first group remained passable in 11 (73,3%) patients, and in the second – in 15 (100%) patients. The physical component of the health of patients in the first group scored 41.7±3.4, in the second group – 48.6±3.4, and the psychological component of health scored 52.1±3.9 and 56.9±3.6, respectively.

Conclusion. Xeno-pericardial patches proved to be more effective in revascularization of an ischemic limb using a deep femoral artery compared with autovenous patches in the long-term postoperative period.

The inpatient costs related to revascularization of lower extremity artery disease in terms of amputation and mortality rates

OBJECTIVE

With the initial utilization of endovascular treatment options in 1970s, the number of procedures performed for lower extremity artery disease (LEAD) both with open surgical (OS) and endovascular (EV) treatment increased, but this did not result in a decrease in the number of amputations. The burden of LEAD still constitutes a huge proportion among the health care costs over the world.

METHODS

The patients who admitted to our clinic between October 2014 and December 2019 with LEAD and required revascularization were enrolled. The total hospitalization costs related to LEAD were registered and divided into two groups as care costs and medical supplies costs.

RESULTS

181 procedures were performed to 133 patients. Mean age was 63.98 ± 11.65 and 115 (86.5%) patients were male. Mean follow-up period was 31.19 ± 17.99 months (95% CI). The most frequent comorbidities were diabetes mellitus (DM) (n = 86, 66.2%) and active smoking (n = 59, 44.4%). Total costs and medical supplies costs were increased in EV group when compared with OS group ($4347.26 ± 3352.96, $3339.28 ± 3459.53 p = .005 v.s. $3318.67 ± 2874.55,$904.42 ± 1209.97 p < .001, respectively). Care costs were increased in OS group when compared with EV group ($2434.85 ± 2641.89 v.s. $1028.56 ± 1397.77 p < .001). The highest total, medical supplies, and care costs were determined in EV + OS group ($13071.32 ± 13717; $6784.91 ± 8332.04; $6286.41 ± 7652.12, respectively).Graft/wound infection related and amputation related costs were 21% of all costs. Amputation-free survival was 71.42% (95% CI) with 21 total amputations. There were linear correlations between mortality and amputation (p = .002); also between mortality and cost (p = .001).

CONCLUSIONS

In mid-long-term period, the care costs are increased with OS; however, EV treatment significantly increases the medical supplies and total costs. The increase in cost is correlated with poor outcome. Although the comorbidities and risk factors of these patients lead the clinicians to perform more challenging endovascular approaches, in mid-long-term period, particularly failed endovascular procedures are not promising in terms of outcomes and costs. We consider that the best-fit therapy on time is cost-effective, life and extremity-saving either, by avoiding deleterious effects of severe ischemia, such as severe pain, tissue loss, and related major adverse cardiaovascular events.

Brazilian Society of Angiology and Vascular Surgery 2023 guidelines on the diabetic foot

The diabetic foot interacts with anatomical, vascular, and neurological factors that challenge clinical practice. This study aimed to compile the primary scientific evidence based on a review of the main guidelines, in addition to articles published on the Embase, Lilacs, and PubMed platforms. The European Society of Cardiology system was used to develop recommendation classes and levels of evidence. The themes were divided into six chapters (Chapter 1 - Prevention of foot ulcers in people with diabetes; Chapter 2 - Pressure relief from foot ulcers in people with diabetes; Chapter 3 -Classifications of diabetic foot ulcers; Chapter 4 - Foot and peripheral artery disease; Chapter 5 - Infection and the diabetic foot; Chapter 6 - Charcot's neuroarthropathy). This version of the Diabetic Foot Guidelines presents essential recommendations for the prevention, diagnosis, treatment, and follow-up of patients with diabetic foot, offering an objective guide for medical practice.

Percutaneous Deep Venous Arterialization: Treatment of Patients with End-Stage Plantar Disease

Background

Percutaneous deep venous arterialization (pDVA) is a minimally invasive technique connecting the tibial arteries below the knee to the tibial venous system into plantar venous circulation to deliver oxygenated blood to otherwise nonperfused foot. This study demonstrated outcomes of pDVA with commercially available equipment and described single-center experience on pDVA for critical limb-threatening ischemia patients with small artery diseases and end-stage plantar disease (ESPD) who were deemed no-option cases.

Methods

A single-center retrospective review was performed on patients who underwent pDVA. Primary end points were successful establishment of tibial vein flow with venous pedal loop, rate of major amputation, and major adverse events over 6 months. Secondary end points were primary and secondary patency rates, minor amputation rates, and wound healing over 6 months.

Results

Forty-two patients with ESPD underwent pDVA. Risk factors identified were hypertension (92.8%), hyperlipidemia (85.7%), diabetes (78.6%), tobacco abuse (42.9%), and chronic kidney disease ≥ stage 3 (42.8%). Three patients were categorized as Rutherford Class 4, 14 patients Class 5, and 25 patients (59.5%) Class 6. Of 42 procedures, 33 (78.6%) were deemed successful. Amputation-free survival at 6 months was reported in 25 patients (60.9%); 16 patients (38.1%) reported minor amputations. Wound healing rate reported at 6 months was 23.8%.

Conclusions

This is one of the largest case series to date with real-world no-option patients undergoing pDVA. pDVA seems a reasonable option for limb salvage in patients with ESPD where traditional arterial revascularization is not feasible. Identifying criteria for patient selection and advanced wound care is important to ensure clinical success. Additional research is required to establish diagnostic guidelines for patients being evaluated for pDVA.

The shifting care and outcomes for patients with endangered limbs - Critical limb ischemia (SCOPE-CLI) registry overview of study design and rationale

BACKGROUND

Critical limb ischemia (CLI), the most severe form of peripheral artery disease, is associated with pain, poor wound healing, high rates of amputation, and mortality (>20% at 1 year). Little is known about the processes of care, patients' preferences, or outcomes, as seen from patients' perspectives. The SCOPE-CLI study was co-designed with patients to holistically document patient characteristics, treatment preferences, patterns of care, and patient-centered outcomes for CLI.

METHODS

This 11-center prospective observational registry will enroll and interview 816 patients from multispecialty, interdisciplinary vascular centers in the United States and Australia. Patients will be followed up at 1, 2, 6, and 12 months regarding their psychosocial factors and health status. Hospitalizations, interventions, and outcomes will be captured for 12 months with vital status extending to 5 years. Pilot data were collected between January and July of 2021 from 3 centers.

RESULTS

A total of 70 patients have been enrolled. The mean age was 68.4 ± 11.3 years, 31.4% were female, and 20.0% were African American.

CONCLUSIONS

SCOPE-CLI is uniquely co-designed with patients who have CLI to capture the care experiences, treatment preferences, and health status outcomes of this vulnerable population and will provide much needed information to understand and address gaps in the quality of CLI care and outcomes.ClinicalTrials.gov identifier (NCT Number): NCT04710563 https://clinicaltrials.gov/ct2/show/NCT04710563.

[Endovascular interventions in patients with glass iii infrainguinal arterial disease: 2-year results]

OBJECTIVE

To evaluate the results of endovascular surgery in patients with chronic limb-threatening ischemia (CLTI) with infrainguinal arterial disease GLASS III.

MATERIAL AND METHODS

Treatment outcomes were analyzed for the period 2017-2018. Inclusion criteria were age over 18 years, CLTI, extended (>20 cm) stenosis de novo and occlusion of femoropopliteal segment (FPS) combined with occlusive lesion of tibial arteries. We analyzed 147 patients divided into 2 groups depending on stenting strategy. FPS-1-TA included 53 patients who underwent angioplasty (± stenting) of femoropopliteal arteries and lower leg arteries resulted at least one patent tibial artery. FPS-2-TA enrolled 94 patients who underwent angioplasty of femoropopliteal arteries and lower leg arteries resulted ≥2 patent tibial arteries. Mean age was 71.0±9.8 years. There were 75 men. Demographics and clinical characteristics of patients were similar.

RESULTS

Technical success rate was 100%. Mean length of stenting was 203 ± 99 mm. Occlusion of all 3 leg arteries correlated with high incidence of femoropopliteal stenting. In the FPS-1-TA group, stents were implanted in 39 patients, in the FPS-2-TA group - in 71 patients (73.6% and 75.5%, respectively, p=0.8). Braided nitinol stents were used for stenting of the lower third of superficial femoral artery and p1-p3 segments. Mean follow-up period was 22.6±1.1 months. Two-year results were not age-specific in our study. Kaplan-Meier overall survival, freedom from amputation and amputation-free survival for the entire sample were 79.6%, 81.0%, and 66.7%, respectively. We compared these values in both groups using Mantel-Cox log-rank test and obtained significant differences (67.9% vs 86.2%, p=0.004; 64.2% vs 90%, p<0.0001; 47.2% vs 77.7%, p<0.0001, respectively).

CONCLUSION

Our results are comparable with literature data regarding freedom from amputation and amputation-free survival. We obtained significant differences in overall survival and freedom from amputation depending on endovascular strategy for tibial arteries. Correction of distal vessels with recanalization of at least two tibial arteries is advisable for endovascular treatment of diffuse complex lesions.

Chronic limb threatening ischemia and diabetes mellitus: the severity of tibial atherosclerosis and outcome after infrapopliteal revascularization

BACKGROUND AND OBJECTIVE

Diabetes mellitus associates with poor outcomes in chronic limb threatening ischemia but data on different hypoglycemic regimens and outcomes are lacking. We analyzed insulin-treated diabetes mellitus, non-insulin-treated diabetes mellitus, and patients without diabetes mellitus.

METHODS

All patients with peripheral artery disease and/or diabetes mellitus and infrapopliteal revascularization in the Department of Vascular Surgery, Turku University Hospital during 2007-2015 were included. Tibial atherosclerosis was categorized into crural index classes of I-IV.

RESULTS

Of the 497 patients, 180 were insulin-treated diabetes mellitus, 94 non-insulin-treated diabetes mellitus, and 223 patients without diabetes mellitus groups (diabetes mellitus 55.1%). Insulin-treated diabetes mellitus was the most ill, youngest (insulin-treated diabetes mellitus-median: 72.4, interquartile range: 64.0-79.5 versus non-insulin-treated diabetes mellitus-76.0, interquartile range: 67.9-83.6 versus patients without diabetes mellitus-77.3, interquartile range: 68.5-83.7, p < 0.001), had the highest body mass index (insulin-treated diabetes mellitus-median: 27.7, interquartile range: 24.0-31.8 versus non-insulin-treated diabetes mellitus-26.3, interquartile range: 23.2-30.3 versus patients without diabetes mellitus-23.9, interquartile range: 21.5-26.9, p < 0.001), and Charlson comorbidity index (insulin-treated diabetes mellitus-65.6% versus non-insulin-treated diabetes mellitus-46.8% versus patients without diabetes mellitus-10.8%, p < 0.001). After endovascular revascularization, limb salvage was poorer for insulin-treated diabetes mellitus (p = 0.046) and non-insulin-treated diabetes mellitus groups (p = 0.011) compared to surgery, but not for patients without diabetes mellitus (p = 0.15). Patients with crural index IV in insulin-treated diabetes mellitus (p = 0.001) and non-insulin-treated diabetes mellitus (p = 0.013) had higher mortality after revascularization. Crural index IV was a risk factor for limb loss (hazard ratio: 1.37, 95% confidence interval: 1.08-1.74, p = 0.008).

CONCLUSIONS

Limb salvage after bypass is better for insulin and non-insulin diabetics, compared to the endovascular approach. Extensive tibial atherosclerosis is an independent risk factor for limb loss. It associates with increased mortality in both insulin and non-insulin diabetics.

Systems Approach to Discovery of Therapeutic Targets for Vein Graft Disease: PPARα Pivotally Regulates Metabolism, Activation, and Heterogeneity of Macrophages and Lesion Development

Supplemental Digital Content is available in the text.

Vein graft failure remains a common clinical challenge. We applied a systems approach in mouse experiments to discover therapeutic targets for vein graft failure.

An indirect comparison by Bayesian network meta-analysis of drug-coated devices versus saphenous vein graft bypass in femoropopliteal arterial occlusive disease

OBJECTIVE

To compare the efficacy and safety between drug-coated devices (DCDs) and bypass surgery with saphenous vein graft (BSV) in femoropopliteal arterial occlusive disease.

METHODS

A Bayesian network meta-analysis and indirect comparison were performed. Randomized controlled trials of BSV, bypass surgery with prosthetic graft, bare metal stents, endoluminal bypass (covered stent), percutaneous transluminal angioplasty, and DCDs treating femoropopliteal arterial occlusive disease were collected. The primary end point was target lesion revascularization/target vessel revascularization, and secondary end points were all-cause mortality, limb salvage, and early complications (PROSPERO registry number: CRD42019136530).

RESULTS

Forty-two trials and 6867 patients were included. The comparison of DCDs and BSV revealed no significant difference in the 1-year target lesion revascularization/target vessel revascularization (DCDs vs BSV: odds ratio [OR], 0.60; 95% credible interval [CrI], 0.16-2.39). Total early complications from BSV were significantly higher than those from DCDs (DCDs vs BSV: OR, 0.14; 95% CrI, 0.05-0.45), and the main complications of BSV were not death related. There was also no significant difference in systemic early complications (DCDs vs BSV: OR, 0.19; 95% CrI, 0.00-7.82) and 1-year amputation rate (DCDs vs BSV: OR, 2.81; 95% CrI, 0.16-89.53). The 30-day (DCDs vs BSV: OR, 0.38; 95% CrI, 0.00-110.46), 1-year (DCDs vs BSV: OR, 0.96; 95% CrI, 0.24-3.29), 2-year (DCDs vs BSV: OR, 1.60; 95% CrI, 0.64-4.95), and 5-year all-cause mortality rates (DCDs vs BSV: OR, 2.05; 95% CrI, 0.92-4.39) showed no significant differences between DCDs and BSV, although there was a noticeable tendency toward significant results of a higher 5-year mortality rate.

CONCLUSIONS

There is no significant difference between DCDs and BSV in short-term efficacy or short- and long-term mortality. Despite traditional BSV remaining the gold standard, DCDs provide a reasonable alternative therapy. In addition, the DCDs have a lower short-term morbidity associated with the procedure at the cost of the possible risk of higher long-term mortality. Clinical trials with more validity are required for a direct comparison between BSV and DCDs.

Validation of the Global Limb Anatomic Staging System in first-time lower extremity revascularization

OBJECTIVE

The Global Limb Anatomic Staging System (GLASS) was developed as a new anatomic classification scheme to grade the severity of chronic limb threatening ischemia. We evaluated the ability of this anatomic grading system to determine major adverse limb events after lower extremity revascularization.

METHODS

We performed a single-institutional retrospective review of 1060 consecutive patients who had undergone 1180 first-time open or endovascular revascularization procedures for chronic limb threatening ischemia from 2005 to 2014. Using the review of angiographic images, the limbs were classified as GLASS stage 1, 2, or 3. The primary composite outcome was reintervention, major amputation (below- or above-the-knee amputation), and/or restenosis (>3.5× step-up by duplex criteria) events (RAS). The secondary outcomes included all-cause mortality, failure to cross the lesion by endovascular methods, and a comparison between bypass vs endovascular intervention. Kaplan-Meier estimates were used to determine the event rates at 1 and 5 years, and Cox regression analysis was used to adjust for baseline differences among the GLASS stages.

RESULTS

Of all patients undergoing first-time revascularization, imaging studies were available for 1180 procedures (91%) for GLASS grading. Of these procedures, 552 were open bypass (47%) and 628 were endovascular intervention (53%). Compared with GLASS stage 1 disease (n = 267, 23%), stage 2 (n = 367; 31%) and stage 3 (n = 546; 42%) disease were associated with a greater risk of RAS at 1 year (stage 1, 33% vs stage 2, 48% vs stage 3, 53%) and 5 years (stage 1, 45% [reference]; stage 2, 65%; hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.3-2.2; P < .001; stage 3, 69%; HR, 2.3; 95% CI, 1.7-2.9; P < .001). These differences were mainly driven by reintervention and restenosis rather than by major amputation. The 5-year mortality was similar for stage 2 and 3 compared with stage 1 disease (stage 1, 40% [reference]; stage 2, 45%; HR, 1.1; 95% CI, 0.8-1.4; P = .69; stage 3, 49%; HR, 1.2; 95% CI, 1.0-1.6; P = .11). For all attempted endovascular interventions, failure to cross a target lesion increased with advancing GLASS stage (stage 1, 4.5% vs stage 2, 6.3% vs stage 3, 13.3%; P < .01). Compared with open bypass (n = 552; 46.8%), endovascular intervention (n = 628; 53.3%) was associated with a higher rate of 5-year RAS for GLASS stage 1 (49% vs 34%; HR, 1.9; 95% CI, [1.1-3.5; P = .03), stage 2 (69% vs 52%; HR, 1.7; 95% CI, 1.2-2.5; P < .01), and stage 3 (83% vs 61%; HR, 1.5; 95% CI, 1.2-2.0; P < .01) disease.

CONCLUSIONS

For patients undergoing first-time lower extremity revascularization, the GLASS can be used to predict for reintervention and restenosis. Bypass resulted in better long-term outcomes compared with endovascular intervention for all GLASS stages.

[Endovascular revascularisation in patients with necrotic wounds and extended infrainguinal arterial disease]

OBJECTIVE

To report own experience of endovascular interventions in patients with extended occlusive lesion (TASC II D) of the femoral-popliteal and tibial arteries and concomitant purulent-necrotic wounds.

MATERIAL AND METHODS

We have analyzed literature data and own experience of endovascular interventions in patients with extended occlusive lesion (TASC II D) of the femoral-popliteal and tibial arteries and concomitant purulent-necrotic wounds.

RESULTS

Endovascular strategy is preferable in a certain subgroup of patients with extended infrainguinal lesions.

CONCLUSION

Considering own data, we assumed the need for routine correction of outflow pathways (simultaneous angioplasty of at least 2 tibial arteries). Primary results are encouraging, but further research is required.

Modified frailty index as an indicator for outcomes, discharge status, and readmission after lower extremity bypass surgery for critical limb ischemia

Frailty has been associated with poor postoperative outcomes. This study evaluated the 5-factor modified frailty index (mFI-5) to assess complications, mortality, discharge disposition, and readmission in patients undergoing lower extremity (LE) bypass for critical limb ischemia (CLI).The National Surgical Quality Improvement Program vascular module (2011-2017) was utilized to identify patients undergoing LE bypass for CLI. Adverse events included infectious complications, bleeding complications, prolonged ventilation, amputation, readmission, and death. Patients were divided into groups based on mFI-5 scores: mFI1 (0), mFI2 (0.2), mFI3 (0.4), and mFI4 (0.6-1). Data were analyzed using the Cochran-Mantel-Haenszel statistic for general association and multivariable logistic regression. About 11,530 patients undergoing bypass for CLI were identified (42% rest pain and 58% tissue loss; 23% mFI1, 31% mFI2, 27% mFI3, and 19% mFI4; 64% men and 36% women). An increase in mFI-5 was associated with higher 30-day mortality (mFI1 = 0.62%; mFI12 = 1.45%; mFI13 = 1.35%; and mFI14 = 3.09%; P < .0001). After adjustment for age, mFI4 was associated with increased mortality compared with mFI1 (odds ratio, 3.80; 95% confidence interval, 1.69-8.54). Increased mFI-5 was associated with bleeding complications, wound infections, urinary tract infections, prolonged ventilation, sepsis, unplanned reoperations, and discharge to nonhome destination (all P < .01). Compared with mFI1 (13.5%), mFI4 was associated with increased 30-day readmission (24.8%, P < .0001). In patients undergoing LE bypass for CLI, higher mFI-5 was associated with increased postoperative complications, in-hospital and 30-day mortality, nonhome discharge, and 30-day readmission. The mFI-5 as an easily calculated tool can identify patients at high risk for inferior outcomes. It should be incorporated into discharge planning after LE bypass for CLI.

Lower Limb Revascularization for Peripheral Arterial Disease in 10,951 Procedures over 11 years in a Public Health System: A Descriptive Analysis of the Largest Brazilian City

BACKGROUND

Worldwide, peripheral arterial disease (PAD) is a disease with high morbidity, affecting more than 200 million people. Our objective was to analyze the surgical treatment for PAD performed in the Unified Health System of the city of São Paulo during the last 11 years based on publicly available data.

METHODS

The study was conducted with data analysis available on the TabNet platform, belonging to the DATASUS. Public data (government health system) from procedures performed in São Paulo between 2008 and 2018 were extracted. Sex, age, municipality of residence, operative technique, number of surgeries (total and per hospital), mortality during hospitalization, mean length of stay in the intensive care unit and amount paid by the government system were analyzed.

RESULTS

A total of 10,951 procedures were analyzed (either for claudicants or critical ischemia-proportion unknown); 55.4% of the procedures were performed on males, and in 50.60%, the patient was older than 65 years. Approximately two-thirds of the patients undergoing these procedures had residential addresses in São Paulo. There were 363 in-hospital deaths (mortality of 3.31%). The hospital with the highest number of surgeries (n = 2,777) had lower in-hospital mortality (1.51%) than the other hospitals. A total of $20,655,272.70 was paid for all revascularizations.

CONCLUSIONS

Revascularization for PAD treatment has cost the government system more than $20 million over 11 years. Endovascular surgeries were performed more often than open surgeries and resulted in shorter hospital stays and lower perioperative mortality rates.

Failed Prior Endovascular Interventions Do Not Affect 30-day Cardiovascular or Limb-related Outcomes of Infrainguinal Bypasses for Chronic Limb Threatening Ischemia

BACKGROUND

It is often hypothesized that failed prior endovascular intervention could adversely affect the outcome of subsequent infrainguinal bypass in the corresponding limb. However, this perception is not well supported in the literature because of conflicting data. The aim of this study is to address this controversial issue via analysis of a multicenter prospectively collected database.

METHODS

Patients who underwent infrainguinal bypass for chronic limb threatening ischemia (CLTI) were identified in the targeted American College of Surgeons National Surgical Quality Improvement Program database from 2011 to 2017. These patients were stratified into 4 groups: first time femoral-popliteal bypass, femoral-popliteal bypass after failed prior endovascular revascularization, first time femoral-tibial bypass, and femoral-tibial bypass after failed prior endovascular revascularization. Thirty-day outcomes including mortality, graft patency, major amputations, and major organ dysfunction were measured.

RESULTS

We identified 7,044 patients who underwent surgical bypasses for CLTI. Patients were mostly well matched among the 4 groups except for differences in sex, hypertension, and preoperative renal function. In terms of major adverse cardiovascular events and major adverse limb events, femoral-popliteal or femoral-tibial bypasses after failed prior endovascular intervention had comparable 30-day outcomes to first-time bypasses. However, patients with failed prior endovascular intervention had increased rates of postoperative wound infection, required significantly more blood transfusions, and had longer operative time.

CONCLUSIONS

Failed prior endovascular intervention does not adversely affect 30-day outcomes of subsequent infrainguinal bypass surgery in mortality, limb salvage, or other major cardiovascular complications.

Current review with evolving management strategies in critical limb ischemia

Critical limb ischemia represents the end stage of peripheral artery disease, which is associated with impaired quality of life and considerable morbidity and mortality. Economical impact of the disease is huge with a substantial burden on patients, healthcare providers, and resources. Varied therapeutic strategies have been employed in the management of these patients. These patients usually have complex multilevel occlusive arteriopathy with significant comorbidities, rendering surgical interventions undesirable in many cases. Recent therapeutic advances with evolving endovascular techniques and gene or cell-based therapies have the potential to dramatically change the therapeutic outlook in these patients.

Endovascular-First Treatment Is Associated With Improved Amputation-Free Survival in Patients With Critical Limb Ischemia

BACKGROUND

Critical limb ischemia remains a difficult disease to treat, with limited level one data. The BEST-CLI trial (Best Endovascular vs Best Open Surgical Therapy in Patients with Critical Limb Ischemia) is attempting to answer whether initial treatment with open surgical bypass or endovascular therapy improves outcomes, although it remains in enrollment. This study aims to compare amputation-free survival and reintervention rates in patients treated with initial open surgical bypass or endovascular intervention for ischemic ulcers of the lower extremities.

METHODS AND RESULTS

Using California nonfederal hospital data linked to statewide death data, all patients with lower extremity ulcers and a diagnosis of peripheral artery disease who underwent a revascularization procedure from 2005 to 2013 were identified. Propensity scores were formulated from baseline patient characteristics. Inverse probability weighting was used with Kaplan-Meier analysis to determine amputation-free survival and time to reintervention for open versus endovascular treatment. Mixed-effects Cox proportional hazards modeling was used to adjust for patient ability to manage their disease and hospital revascularization volume. A total of 16 800 patients were identified. Open surgical bypass was the initial treatment in 5970 (36%) while 10 830 (64%) underwent endovascular interventions. Patients in the endovascular group were slightly younger compared with the open group (70 versus 71 years, ±12 years; P<0.001). Endovascular-first patients were more likely to have comorbid renal failure (36% versus 24%), coronary artery disease (34% versus 32%), congestive heart failure (19% versus 15%), and diabetes mellitus (65% versus 58%; all P values <0.05). After inverse propensity weighting as well as adjustment for patient ability to manage their disease and hospital revascularization experience, open surgery first was associated with a worse amputation-free survival (hazard ratio, 1.16; 95% CI, 1.13-1.20) with no difference in mortality (hazard ratio, 0.94; 95% CI, 0.89-1.11). Endovascular first was associated with higher rates of reintervention (hazard ratio, 1.19; 95% CI, 1.14-1.23).

CONCLUSIONS

Patients with critical limb ischemia have multiple comorbidities, and initial surgical bypass is associated with poorer amputation-free survival compared with an endovascular-first approach, perhaps due to increased severity of wounds at the time of presentation.

Endovascular Extra-Anatomic Femoro-Popliteal Bypass for Limb Salvage in Chronic Critical Limb Ischemia

PURPOSE

To report the initial clinical experience with fully endovascular extra-anatomic femoro-popliteal bypass (FPB) for limb salvage in patients with critical limb ischemia (CLI) and no traditional endovascular or surgical revascularization options.

METHODS

Between June 2013 and May 2018, endovascular procedure was proposed for limb salvage during multidisciplinary team meeting in fifteen hospitalized patients (median age 67 years; 73% men) with CLI and a high risk of major amputation. Primary outcome was amputation-free survival at 1 year. Secondary outcomes included mortality, cardiovascular (CV) events and major limb amputation at 1 year, primary/secondary bypass patency and wound healing at the last follow-up visit. Procedure-related complications (deaths, CV events, hemorrhages) were recorded through 30 days.

RESULTS

Technical procedure success rate was 100%. Major peri-procedural outcomes occurred in two patients (13%): One patient died secondary to cardiogenic shock; one patient suffered acute coronary syndrome associated with iliopsoas bleeding. No major amputation occurred through 30 days. Median follow-up period was 21.5 (18.25-45.5) months (last follow-up visits on April 2019). Amputation-free survival at 1-year and at the last follow-up visit was 80% and 53%, respectively. Cumulative mortality at 1-year and at the last follow-up visit was 13% and 33%, respectively. Primary and secondary bypass patency was 27% and 60%, respectively. Complete wound healing was achieved in 11 patients (73%).

CONCLUSION

Endovascular extra-anatomic FPB represents an innovative approach for limb salvage in CLI with no traditional endovascular or surgical revascularization options. Our clinical experience highlights that this technique remains challenging because of frequent comorbidities and fragility of this patient population.

LEVEL OF EVIDENCE

Level 4, Case series.

Early-Stage Vascular Response between Bare Metal Stent and Drug-Free Bioresorbable Vascular Scaffold in the Small-Sized Peripheral Artery: A Preclinical Study in Porcine Femoral Arteries

BACKGROUND

The clinical benefits and outcomes of the interventional treatment of small-sized infrapopliteal arteries using stent implantation remain uncertain. The aim of this study was to compare the safety and efficacy of drug-free bioresorbable vascular scaffold (BVS) with that of bare metal stent (BMS) in endovascular treatment of small-sized peripheral arteries.

METHODS

In this study, drug-free BVS and BMS were used in eight porcine models. We compared the angiographic and histomorphometric findings in the two groups at 4 weeks. In each pig, BVS and BMS of adequate sizes were implanted in the small branch (<3 mm) of the femoral artery. Angiography, intravascular ultrasound (IVUS), and histomorphometric analysis were performed at 4 weeks.

RESULTS

In the 4-week follow-up angiography and IVUS examination, the minimal luminal diameter was smaller and diameter stenosis was more severe in the BVS group. Histomorphometric findings indicated that the lumen area in the BVS group was smaller (0.34 ± 0.28 mm² vs. 1.40 ± 0.52 mm², P < 0.001), whereas the neointimal area (2.70 ± 1.28 mm² vs. 1.76 ± 0.66 mm², P = 0.013), area stenosis (85.18 ± 13.14 % vs. 54.99 ± 16.13 %, P < 0.001), inflammatory score (2.07 ± 0.861 vs. 28 ± 0.39, P = 0.003), and fibrin scores (1.24 ± 0.70 vs. 0.79 ± 0.72, P = 0.043) were significantly higher in the BVS group. The injury score was higher in the BMS group. In histopathologic findings, restenosis was mainly due to recoil and distortion of the scaffold in the BVS group.

CONCLUSIONS

Compared with BMS, drug-free BVS was not feasible for small-sized peripheral arteries based on the angiographic, IVUS, and histomorphometric results primarily due to insufficient mechanical support.

[Choice of reconstructive operation in lesions of femoropopliteotibial segment and dubious outflow pathways]

We analysed the results of surgical treatment of 40 patients with lower limb critical ischaemia induced by atherosclerotic lesion of arteries of the femoropopliteotibial segment with dubious outflow pathways. The patients were divided into two groups of 20 each. Group One patients underwent autovenous femoropopliteal or tibial bypass grafting below the fissure of the knee joint and Group Two patients were subjected to profundoplasty with closure of the arteriotomic opening with an autovenous patch. The outflow pathway index in Group One amounted to 7.5±0.09 and in Group Two to 7.45±0.08. Our findings suggest that the use of profundoplasty as reconstructive operation in patients with dubious outflow pathways is pathogenetically substantiated, because it makes it possible to decrease the rate of early postoperative complications by 20% and that of late bypass thromboses by 25%, as well as to increase the level of the physical component of health by 12.1% and that of mental health by 3.2%. A conclusion drawn is that performing profundoplasty in this cohort of patients is appropriate and effective.

The BEST-CLI trial is nearing the finish line and promises to be worth the wait

There is significant variability and equipoise in the management of critical limb ischemia (CLI). The Best Endovascular vs Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI) trial, funded by the National Heart, Lung, and Blood Institute, is a prospective, open label, multicenter, multispecialty randomized controlled trial designed to compare treatment efficacy, functional outcomes, cost-effectiveness, and quality of life for 2100 patients suffering from CLI. BEST-CLI is enrolling those patients who are determined to be candidates for open surgical or endovascular revascularization and is designed to be comprehensive, pragmatic, and balanced. Enrollment is occurring at >130 sites across the world, and BEST-CLI is nearing the finish line. Although the trial has encountered a number of obstacles, they are being successfully navigated. This trial promises to establish an evidence-based standard of care in the management of this population of vulnerable patients.

Functional prognosis of critical limb ischemia and efficacy of restoration of direct flow below the ankle

OBJECTIVE

Patients with critical limb ischemia have serious systemic comorbidities and are at high risk of impairment of limb function. In this study, we assessed the prognostic factors of limbs after revascularization.

METHODS

In this retrospective single-center cohort study, from April 2008 to December 2012, we treated 154 limbs of 121 patients with critical limb ischemia by the endovascular therapy-first approach based on the patients' characteristics. The primary end point was amputation-free survival. Secondary end points were patency of a revascularized artery, major adverse limb events, or death. Furthermore, we investigated the ambulatory status one year after revascularization as prognosis of limb function.

RESULTS

Endovascular therapy was performed in 85 limbs in 65 patients as the initial therapy (endovascular therapy group) and surgical reconstructive procedures (bypass group) were performed in 69 limbs in 56 patients. Early mortality within 30 days was not observed in either group. The primary patency rate was significantly better in the bypass group than in the endovascular therapy group ( p < 0.0001). Furthermore, the secondary patency rate was similar between the two groups ( p = 0.0096). There were no significant differences in amputation-free survival and major adverse limb event between the two groups. Univariate analysis showed that ulcer healing ( p < 0.0001), no hypoalbuminemia ( p = 0.0019), restoration of direct flow below the ankle ( p = 0.0219), no previous cerebrovascular disease ( p = 0.0389), and Rutherford 4 ( p = 0.0469) were predictive factors for preservation of ambulatory status one year after revascularization. In multivariate analysis, ulcer healing ( p < 0.0001) and restoration of direct flow below the ankle ( p = 0.0060) were significant predictors.

CONCLUSIONS

Ulcer healing and restoration of direct flow below the ankle are independently associated with prognosis of limb functions in patients who undergo infrainguinal arterial reconstruction.

Amputation-Free Survival in Patients With Diabetes Mellitus and Peripheral Arterial Disease With Heel Ulcer: Open Versus Endovascular Surgery

Background:

Heel ulcers in patients with diabetes mellitus (DM) and peripheral arterial disease (PAD) are hard to heal. The aim of the present study was to evaluate the difference in amputation-free survival (AFS) between open and endovascular revascularization in patients with DM, PAD, and heel ulcers.

Methods:

Retrospective comparative study of results of open versus endovascular surgery in patients with DM, PAD, and heel ulcer presented at the multidisciplinary diabetes foot clinic between 1983 and 2013.

Results:

Patients with heel ulcers were treated with endovascular intervention (n = 97) and open vascular surgery (n = 30). Kaplan-Meier analysis showed that the AFS was higher in patients undergoing open vascular surgery compared to the endovascular group ( P = .009). Multivariate analysis showed that open vascular surgery versus endovascular therapy (hazard ratio 2.1, 95% confidence interval 1.1-3.9; P = .025) was an independent factor associated with higher AFS. The proportion of patients undergoing endovascular therapy in the former (1983-2000) time period was 47% compared to 89% in the latter (2001-2013) time period ( P < .001).

Conclusion:

The AFS was higher after open than endovascular surgery among patients with DM and PAD with heel ulcer. These results suggest that open vascular surgery should be offered more often as opposed to current practice.

Long-Term Limb Salvage and Amputation-Free Survival After Femoropopliteal Bypass and Femoropopliteal PTA for Critical Ischemia in a Clinical Cohort

Objective:

This population-based retrospective cohort study investigates long-term results of femoropopliteal bypass and femoropopliteal endovascular intervention (PTA) in patients with critical ischemia, with focus on limb salvage and amputation-free survival.

Methods:

All patients who underwent femoropopliteal bypass or femoropopliteal PTA for critical ischemia without other simultaneous intervention between 1999 and 2013 were included. Stratification was according to treatment modality and symptoms, rest pain, or ischemic ulcer/gangrene. We assessed technical success, 30-day complications, length of stay, recurrent interventions, limb salvage, survival, and amputation-free survival in all patients.

Results:

We identified 292 operations in 264 patients, 140 bypass and 152 PTA. In 32 PTA cases, the patients were explicitly deemed unfit for bypass surgery. This group had significantly inferior technical success and limb salvage ( P = .00). In other patients, technical success was 96% for bypass and 93% for PTA, while limb salvage after 5 years was 78% for bypass and 81% for PTA. Reoperation for local complications was performed in 16% after bypass and 2% after PTA ( P = .00). Mean length of stay was 8 days after bypass and 1.9 days after PTA ( P = .00).

Conclusions:

Long-term follow-up showed similar technical success and good limb salvage for both PTA and bypass patients in this clinical cohort. Patients who were unfit for bypass surgery had significantly inferior technical success and limb salvage. PTA was associated with shorter hospital stay and fewer reoperations for local complications. The findings support a PTA first strategy in all cases where technical success is likely.

[Effectiveness of biological prosthesis for femoro-femoral bypass in high risk patients]

AIM

To compare synthetic and biological prostheses for femoral bypass surgery.

MATERIAL AND METHODS

There were 40 patients with critical ischemia of lower extremities due to atherosclerotic lesion of aorto-iliac segment and severe comorbidities. They were divided into 2 groups by 20 patients. C-shaped femoro-femoral bypass with synthetic polytetrafluoroethylene and lavsan prostheses was performed in the first group and S-shaped bypass procedure with biological prosthesis from the internal thoracic arteries of the bull - in the second group.

RESULTS

Biological prosthesis is associated with reduced early postoperative morbidity by 10%, late graft thrombosis incidence by 20% and increased physical and psychological health by 7.1%.

CONCLUSION

S-shaped femoro-femoral bypass with a biological prosthesis from the internal thoracic arteries of the bull is pathogenetically substantiated and effective.

Current Status of Arterial Revascularization for the Treatment of Critical Limb Ischemia in Infrainguinal Atherosclerotic Disease

Critical limb ischemia (CLI) is the most severe form of peripheral arterial disease (PAD) that may result in limb loss and even death; thus, the fast and proper treatment should be employed as earlier as possible to prevent these catastrophic consequences. Arterial revascularization is almost always an indispensable treatment option for CLI. Although both endovascular and surgical revascularization procedures have an important role, nowadays, the hybrid revascularization as a combination of these revascularization procedures has also gained increasing popularity in the treatment of patients with CLI. This review provides an update on the arterial revascularization strategies for the treatment of CLI.

3D-printed vascular networks direct therapeutic angiogenesis in ischaemia

Arterial bypass grafts remain the gold standard for the treatment of end-stage ischaemic disease. Yet patients unable to tolerate the cardiovascular stress of arterial surgery or those with unreconstructable disease would benefit from grafts that are able to induce therapeutic angiogenesis. Here, we introduce an approach whereby implantation of 3D-printed grafts containing endothelial-cell-lined lumens induces spontaneous, geometrically guided generation of collateral circulation in ischaemic settings. In rodent models of hind-limb ischaemia and myocardial infarction, we demonstrate that the vascular patches rescue perfusion of distal tissues, preventing capillary loss, muscle atrophy and loss of function. Inhibiting anastomoses between the construct and the host's local capillary beds, or implanting constructs with unpatterned endothelial cells, abrogates reperfusion. Our 3D-printed grafts constitute an efficient and scalable approach to engineer vascular patches able to guide rapid therapeutic angiogenesis and perfusion for the treatment of ischaemic diseases.

[Free autovenous graft with destructed valves in treatment of severe ischemia of lower extremities]

AIM

to improve treatment of patients with severe atherosclerotic lesion of lower extremities arteries followed by critical ischemia by optimization of femoropopliteal bypass surgery.

MATERIAL AND METHODS

Treament and survey of 60 patients with severe atherosclerotic lesion of femoropopliteotibial segment and critical lower limb ischemia were analyzed. Patients were divided into 2 groups depending on technique of femoropopliteal bypass. Conventional in situ autovenous technique was used in group 1. In the second group we used original method of free autovenous graft with destructed valves.

RESULTS

Technique of free autovenous graft with destructed valves decreases incidence of early postoperative complications by 13.3%, remote thrombosis of graft by 13.3%. Also it increases physical and mental components of health by 7.9% and 3.1% respectively.

CONCLUSION

Use of free autovenous graft with destructed valves is reasonable and improves results of treatment.

Design and Rationale of the Best Endovascular Versus Best Surgical Therapy for Patients With Critical Limb Ischemia (BEST-CLI) Trial

BACKGROUND

Critical limb ischemia (CLI) is increasing in prevalence, and remains a significant source of mortality and limb loss. The decision to recommend surgical or endovascular revascularization for patients who are candidates for both varies significantly among providers and is driven more by individual preference than scientific evidence.

METHODS AND RESULTS

The Best Endovascular Versus Best Surgical Therapy for Patients With Critical Limb Ischemia (BEST-CLI) Trial is a prospective, randomized, multidisciplinary, controlled, superiority trial designed to compare treatment efficacy, functional outcomes, quality of life, and cost in patients undergoing best endovascular or best open surgical revascularization. Approximately 140 clinical sites in the United States and Canada will enroll 2100 patients with CLI who are candidates for both treatment options. A pragmatic trial design requires consensus on patient eligibility by at least 2 investigators, but leaves the choice of specific procedural strategy within the assigned revascularization approach to the individual treating investigator. Patients with suitable single-segment of saphenous vein available for potential bypass will be randomized within Cohort 1 (n=1620), while patients without will be randomized within Cohort 2 (n=480). The primary efficacy end point of the trial is Major Adverse Limb Event-Free Survival. Key secondary end points include Re-intervention and Amputation-Free-Survival and Amputation Free-Survival.

CONCLUSIONS

The BEST-CLI trial is the first randomized controlled trial comparing endovascular therapy to open surgical bypass in patients with CLI to be carried out in North America. This landmark comparative effectiveness trial aims to provide Level I data to clarify the appropriate role for both treatment strategies and help define an evidence-based standard of care for this challenging patient population.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02060630.

Optoacoustic Imaging of Human Vasculature: Feasibility by Using a Handheld Probe

Purpose To investigate whether multispectral optoacoustic tomography (MSOT) developed for deep-tissue imaging in humans could enable the clinical assessment of major blood vessels and microvasculature. Materials and Methods The study was approved by the Institutional Review Board of the University Medical Center Groningen (CCMO-NL-43587) and registered in the Dutch National Trial Registry (NTR4125). The authors designed a real-time handheld optoacoustic scanner for human use, based on a concave 8-MHz transducer array, attaining 135° angular coverage. They applied a single-pulse-frame (SPF) sequence, which enabled motion insensitive optoacoustic imaging during handheld operation. SPF optoacoustic imaging was applied to imaging arteries and microvascular landmarks in the lower extremities of 10 healthy volunteers. The diameters selected microvessels were determined by measuring the full width at half maximum through the vessels in the MSOT images. Duplex ultrasonography was performed on the same landmarks in seven of the 10 volunteers for subjective comparison to the corresponding optoacoustic images. Results Optoacoustic imaging resolved blood vessels as small as 100 µm in diameter and within 1 cm depth. Additionally, MSOT provided images reflecting hemoglobin oxygen saturation in blood vessels, clearly identifying arteries and veins, and was able to identify pulsation in arteries during imaging. Larger blood vessels, specifically the tibialis posterior and the dorsalis pedis arteries, were also visualized with MSOT. Conclusion Handheld MSOT was found to be capable of clinical vascular imaging, providing visualization of major blood vessels and microvasculature and providing images of hemoglobin oxygen saturation and pulsation. (©) RSNA, 2016.

Reconstructive vascular surgery and the extent of tissue damage due to diabetic foot ulcers relates to risk of new ulceration in patients with PAD

OBJECTIVE

There is limited information regarding new ulceration following the healing of ischaemic foot ulcers in diabetic patients. Our aim is to study new ulcerations in the same foot as the previous ulcer(s) in patients with diabetes and severe peripheral artery disease (PAD).

METHOD

Patients with diabetes and severe PAD who healed from previous ulcer(s) (Wagner grade 1-5, at or below the ankle), were recruited for the prospective study from the time of healing of their ulcer. Patients were followed up regarding new ulceration, and their treatments and ulcer status noted either directly or on examination of medical records.

RESULTS

We analysed the data on 602 patients with diabetes and severe PAD with healed foot ulcers, either primarily (n=443, 74%) or after minor amputation (n=159, 26%). Of these 51% (n=305) had revascularisation before healing from the previous ulcer, 34% (n=202) developed a new ulcer on the same foot within 15 months (range 0-106). Amputation was required by 22% (n=45) of patients, with a new ulcer on the same foot. The median survival time of all patients (n=602) was 54 months. By regression analysis, a low maximal Wagner grade for the previous ulcer and reconstructive vascular surgery was related to a decreased risk of developing new ulcers in the same foot.

CONCLUSION

Patients with diabetes and ischaemic foot ulcers have a high-risk for developing new ulcers and amputation in the same foot after healing. The extent of tissue involvement in the previous ulcer and reconstructive vascular surgery affected the risk for development of new ulcers.

A prosurvival and proangiogenic stem cell delivery system to promote ischemic limb regeneration

Stem cell therapy is one of the most promising strategies to restore blood perfusion and promote muscle regeneration in ischemic limbs. Yet its therapeutic efficacy remains low owing to the inferior cell survival under the low oxygen and nutrient environment of the injured limbs. To increase therapeutic efficacy, high rates of both short- and long-term cell survival are essential, which current approaches do not support. In this work, we hypothesized that a high rate of short-term cell survival can be achieved by introducing a prosurvival environment into the stem cell delivery system to enhance cell survival before vascularization is established; and that a high rate of long-term cell survival can be attained by building a proangiogenic environment in the system to quickly vascularize the limbs. The system was based on a biodegradable and thermosensitive poly(N-Isopropylacrylamide)-based hydrogel, a prosurvival and proangiogenic growth factor bFGF, and bone marrow-derived mesenchymal stem cells (MSCs). bFGF can be continuously released from the system for 4weeks. The released bFGF significantly improved MSC survival and paracrine effects under low nutrient and oxygen conditions (0% FBS and 1% O2) in vitro. The prosurvival effect of the bFGF on MSCs was resulted from activating cell Kruppel-like factor 4 (KLF4) pathway. When transplanted into the ischemic limbs, the system dramatically improved MSC survival. Some of the engrafted cells were differentiated into skeletal muscle and endothelial cells, respectively. The system also promoted the proliferation of host cells. After only 2weeks of implantation, tissue blood perfusion was completely recovered; and after 4weeks, the muscle fiber diameter was restored similarly to that of the normal limbs. These pronounced results demonstrate that the developed stem cell delivery system has a potential for ischemic limb regeneration.

STATEMENT OF SIGNIFICANCE

Stem cell therapy is a promising strategy to restore blood perfusion and promote muscle regeneration in ischemic limbs. Yet its therapeutic efficacy remains low owing to the inferior cell survival under the ischemic environment of the injured limbs. To increase therapeutic efficacy, high rate of cell survival is essential, which current approaches do not support. In this work, we tested the hypothesis that a stem cell delivery system that can continuously release a prosurvival and proangiogenic growth factor will promote high rates of cell survival in the ischemic limbs. The prosurvival effect could augment cell survival before vascularization is established, while the proangiogenic effect could stimulate quick angiogenesis to achieve long-term cell survival. Meanwhile, the differentiation of stem cells into endothelial and myogenic lineages, and cell paracrine effects will enhance vascularization and muscle regeneration.

A comparative evaluation of risk-adjustment models for benchmarking amputation-free survival after lower extremity bypass

BACKGROUND

Providing patients and payers with publicly reported risk-adjusted quality metrics for the purpose of benchmarking physicians and institutions has become a national priority. Several prediction models have been developed to estimate outcomes after lower extremity revascularization for critical limb ischemia, but the optimal model to use in contemporary practice has not been defined. We sought to identify the highest-performing risk-adjustment model for amputation-free survival (AFS) at 1 year after lower extremity bypass (LEB).

METHODS

We used the national Society for Vascular Surgery Vascular Quality Initiative (VQI) database (2003-2012) to assess the performance of three previously validated risk-adjustment models for AFS. The Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL), Finland National Vascular (FINNVASC) registry, and the modified Project of Ex-vivo vein graft Engineering via Transfection III (PREVENT III [mPIII]) risk scores were applied to the VQI cohort. A novel model for 1-year AFS was also derived using the VQI data set and externally validated using the PIII data set. The relative discrimination (Harrell c-index) and calibration (Hosmer-May goodness-of-fit test) of each model were compared.

RESULTS

Among 7754 patients in the VQI who underwent LEB for critical limb ischemia, the AFS was 74% at 1 year. Each of the previously published models for AFS demonstrated similar discriminative performance: c-indices for BASIL, FINNVASC, mPIII were 0.66, 0.60, and 0.64, respectively. The novel VQI-derived model had improved discriminative ability with a c-index of 0.71 and appropriate generalizability on external validation with a c-index of 0.68. The model was well calibrated in both the VQI and PIII data sets (goodness of fit P = not significant).

CONCLUSIONS

Currently available prediction models for AFS after LEB perform modestly when applied to national contemporary VQI data. Moreover, the performance of each model was inferior to that of the novel VQI-derived model. Because the importance of risk-adjusted outcome reporting continues to increase, national registries such as VQI should begin using this novel model for benchmarking quality of care.

Regulating myogenic differentiation of mesenchymal stem cells using thermosensitive hydrogels

Stem cell therapy has potential to regenerate skeletal muscle tissue in ischemic limb. However, the delivered stem cells experience low rate of myogenic differentiation. Employing injectable hydrogels as stem cell carriers may enhance the myogenic differentiation as their modulus may be tailored to induce the differentiation. Yet current approaches used to manipulate hydrogel modulus often simultaneously vary other properties that also affect stem cell differentiation, such as chemical structure, composition and water content. Thus it is challenging to demonstrate the decoupled effect of hydrogel modulus on stem cell differentiation. In this report, we decoupled the hydrogel modulus from chemical structure, composition, and water content using injectable and thermosensitive hydrogels. The hydrogels were synthesized from N-isopropylacrylamide (NIPAAm), acrylic acid (AAc), and degradable macromer 2-hydroxyethyl methacrylate-oligomer [oligolatide, oligohydroxybutyrate, or oligo(trimethylene carbonate)]. We found that using the same monomer composition and oligomer chemical structure but different oligomer length can independently vary hydrogel modulus. Rat bone marrow mesenchymal stem cells (MSCs) were encapsulated in the hydrogels with elastic expansion moduli of 11, 20, and 40 kPa, respectively. After 14 days of culture, significant myogenic differentiation was achieved for the hydrogel with elastic expansion modulus of 20 kPa, as judged from both the gene and protein expression. In addition, MSCs exhibited an elastic expansion modulus-dependent proliferation rate. The most significant proliferation was observed in the hydrogel with elastic expansion modulus of 40 kPa. These results demonstrate that the developed injectable and thermosensitive hydrogels with suitable modulus has the potential to deliver stem cells into ischemic limb for enhanced myogenic differentiation and muscle regeneration.

STATEMENT OF SIGNIFICANCE

Stem cell therapy for skeletal muscle regeneration in ischemic limb experiences low rate of myogenic differentiation. Employing injectable hydrogels as stem cell carriers may enhance the myogenic differentiation as hydrogel modulus may be modulated to induce the differentiation. Yet current approaches used to modulate hydrogel modulus may simultaneously vary other properties that also affect stem cell myogenic differentiation, such as chemistry, composition and water content. In this report, we decoupled the hydrogel modulus from chemistry, composition, and water content using injectable and thermosensitive hydrogels. We found that mesenchymal stem cells best differentiated into myogenic lineage in the hydrogel with elastic modulus of 20 kPa.