Preventing Major Amputations in Patients with Critical Limb Ischemia

Allogenic Vertebral Body Adherent Mesenchymal Stromal Cells Promote Muscle Recovery in Diabetic Mouse Model of Limb Ischemia

BACKGROUND

Chronic limb-threatening ischemia (CLTI) carries a significant risk for amputation, especially in diabetic patients with poor options for revascularization. Phase I trials have demonstrated efficacy of allogeneic mesenchymal stromal cells (MSC) in treating diabetic CLTI. Vertebral bone-adherent mesenchymal stromal cells (vBA-MSC) are derived from vertebral bodies of deceased organ donors, which offer the distinct advantage of providing a 1,000x greater yield compared to that of living donor bone aspiration. This study describes the effects of intramuscular injection of allogenic vBA-MSC in promoting limb perfusion and muscle recovery in a diabetic CLTI mouse model.

METHODS

A CLTI mouse model was created through unilateral ligation of the femoral artery in male polygenic diabetic TALLYHO mice. The treated mice were injected with vBA-MSC into the gracilis muscle of the ischemic limb 7 days post ligation. Gastrocnemius or tibialis muscle was assessed postmortem for fibrosis by collagen staining, capillary density via immunohistochemistry, and mRNA by quantitative real-time polymerase chain reaction (PCR). Laser Doppler perfusion imaging and plantar flexion muscle testing (MT) were performed to quantify changes in limb perfusion and muscle function.

RESULTS

Compared to vehicle (Veh) control, treated mice demonstrated indicators of muscle recovery, including decreased fibrosis, increased perfusion, muscle torque, and angiogenesis. PCR analysis of muscle obtained 7 and 30 days post vBA-MSC injection showed an upregulation in the expression of MyoD1 (P = 0.03) and MyH3 (P = 0.008) mRNA, representing muscle regeneration, vascular endothelial growth factor A (VEGF-A) (P = 0.002; P = 0.004) signifying angiogenesis as well as interleukin (IL-10) (P < 0.001), T regulatory cell marker Foxp3 (P = 0.04), and M2-biased macrophage marker Mrc1 (CD206) (P = 0.02).

CONCLUSIONS

These findings indicate human allogeneic vBA-MSC ameliorate ischemic muscle damage and rescue muscle function. These results in a murine model will enable further studies to develop potential therapies for diabetic CLTI patients.

The experiences and needs of people with dysvascular lower extremity amputations: a qualitative systematic review and meta-synthesis

PURPOSE

The aim of this review is to synthesise the experiences and needs of people who had undergone dysvascular lower extremity amputations. Given the increasing global prevalence of vascular diseases like diabetes mellitus and peripheral arterial disease, the risk of requiring an amputation remains high.

MATERIALS AND METHODS

This systematic review follows the PRISMA and ENTREQ reporting guidelines. Seven databases were searched for qualitative studies from January 2011 to October 2023. In total 6435 studies were obtained, where 1146 were duplicates and 5271 studies failed to meet the eligibility criteria. The remaining 18 studies were synthesised using Sandelowski and Barroso's approach and appraised using the CASP checklist.

RESULTS

Four themes emerged from the meta-synthesis: (1) making the decision to amputate, (2) difficulties in the physical adaptation to limb loss, (3) psychosocial consequences of living with an amputation, and (4) regaining control and building hope.

CONCLUSIONS

Having dysvascular lower extremity amputations is a complicated experience as not only was the pre-amputation pain relieved, but a new set of physical, emotional and social challenges would surface after the amputation. These synthesised findings serve as a platform to explore the factors behind the various experiences faced by these people and how healthcare professionals can help them in their adjustment.

Superficial Femoral Artery Remote Endarterectomy: A Systematic Review And Meta-analysis

BACKGROUND

Objective: Remote Superficial Femoral Artery Endarterectomy (RSFAE) is a hybrid procedure with low risk for peri-operative complications and promising patency rates over time. The aim of this study was to summarize current literature and to determine the role of RSFAE in limb salvage with regards to technical success, limitations, patency rates and long-term outcomes.

METHODS

This systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Overall 19 studies were identified, comprising 1,200 patients with extensive femoropopliteal disease among whom 40% presented with chronic limb threatening ischemia. The average technical success rate was 96%, with a 7% rate for peri-operative distal embolization and 13% rate for SFA perforation. The primary patency was 64% and 56%, primary assisted patency was 82% and 77% and secondary patency was 89% and 72% at 12 and 24 months follow up respectively.

CONCLUSION

For long femoropopliteal TASC C/D lesions, RSFAE appears to be a minimally invasive hybrid procedure with acceptable perioperative morbidity, low mortality, and acceptable patency rates. RSFAE should be considered an alternative to open surgery or a bridge to bypass procedure.

Validating fatty acid binding protein 3 as a diagnostic and prognostic biomarker for peripheral arterial disease: A three-year prospective follow-up study

BACKGROUND

Patients with peripheral arterial disease (PAD) often remain undiagnosed and therefore suboptimally managed. Here, we investigated the diagnostic and prognostic potential of fatty acid binding protein 3 (FABP3) in patients with PAD.

METHODS

In the discovery phase, 374 PAD and 184 non-PAD patients were recruited from vascular surgery ambulatory clinics at St. Michael's Hospital (Toronto, Ontario, Canada) between October 4, 2017 to October 29, 2018. The diagnostic ability of baseline FABP3 level was investigated through receiver operator characteristic (ROC) curves to determine two cutoff points: 1) an exclusionary "rule out" cutoff point, and 2) a confirmatory "rule in" cutoff point. Next, these cutoff points were confirmed in the external validation phase using a separate cohort of 312 patients (180 PAD and 132 non-PAD) recruited from ambulatory vascular surgery clinics at St. Michael's Hospital (Canada) between November 6, 2018-July 30, 2019. Cox regression analyses were used to explore the independent association between FABP3 and major adverse limb events (MALE - defined as need for arterial revascularization or major amputation) and decrease in ankle-brachial index (ABI -defined as drop ≥0.15) during 3 years of follow-up.

FINDINGS

In the discovery phase, FABP3 levels were significantly elevated in patients with PAD compared to non-PAD patients. ROC analysis demonstrated that FABP3 had an AUC of 0.83 (95% CI: 0.81-0.86, p-value < 0.001). FABP3 exclusionary cutoff was <1.55 ng/ml (sensitivity = 96%; specificity = 40%), whereas FABP3 confirmatory cutoff was >3.55 ng/ml (sensitivity = 43%; specificity = 95%) - values that were confirmed in the external validation phase. Cox regression analysis demonstrated FABP3 to be an independent predictor of increase in MALE [HR = 1.14 (1.03-1.29); p-value = 0.010] and worsening PAD status (drop in ABI >0.15 [HR = 1.11 (1.02-1.19); p-value = 0.009]).

INTERPRETATION

Our findings suggested that FABP3 levels can be used as both a diagnostic and prognostic biomarker for PAD, and may facilitate risk stratification in select individuals for purposes of vascular evaluation or intensive medical management.

FUNDING

Funding for this study was provided by the Bill and Vicky Blair Foundation.

Trends in the incidence rates of lower limb amputation due to nondiabetic peripheral artery disease in a large industrial city in Western Siberia, Russia: A review from 1996 to 2019

BACKGROUND

lower limb amputation (LLA) is a growing problem in the population with and without diabetes mellitus. Monitoring the incidence rates of LLA is important for health care planning and has implications for the future problems of medical and social care.

OBJECTIVE

This study aimed to determine the trends in incidence rates of LLA due to nondiabetic peripheral artery disease in Novokuznetsk, Western Siberia, Russia.

STUDY DESIGN

An observational study.

METHODS

Data on all transtibial and transfemoral amputations performed in inpatient facilities in Novokuznetsk from 1996 to 2019 were derived from the regional Register of patients with limb amputations. The rates were calculated per 100,000 population.

RESULTS

A total of 2448 persons with amputations due to nondiabetic peripheral artery disease were included in this study (3191 amputations). The overall incidence rate of LLA in Novokuznetsk increased from 14.6 in 1996 to 30.4 in 2019. The proportion of persons older than 60 years increased from 15.5% in 1996 to 20.3% in 2019.

CONCLUSION

The expected aging of the population and increasing incidence of LLA are relevant issues in Russia. These findings can contribute to improving healthcare services and the development of prevention programs to reverse the alarming trend.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The association between socioeconomic distress communities index and amputation among patients with peripheral artery disease

Background

Socioeconomic factors have been shown to be associated with amputation in peripheral artery disease (PAD); however, analyses have normally focused on insurance status, race, or median income. We sought to determine whether community-level socioeconomic distress was associated with major amputation and if that association differed by race.

Materials and methods

Community-level socioeconomic distress was measured using the distressed communities index (DCI). The DCI is a zip code level compositive socioeconomic score (0-100) that accounts for unemployment, education level, poverty rate, median income, business growth, and housing vacancies. A distressed community was defined as a zip code with DCI of 40 or greater. We calculated one-year risk of major amputation by DCI score for individuals with peripheral artery disease in South Carolina, 2012-2017. Treating death as competing event, we reported Fine and Gray subdistribution hazards ratios (sdHR), adjusted for patient demographic and clinical comorbidities associated with amputation. Further analyses were completed to identify potential differences in outcomes within strata of race and DCI.

Results

Among 82,848 individuals with peripheral artery disease, the one-year incidence of amputation was 3.5% (95% CI: 3.3%, 3.6%) and was significantly greater in distressed communities than non-distressed communities (3.9%; 95% CI: 3.8%, 4.1% vs. 2.4%; 95% CI: 2.2%, 2.6%). After controlling for death and adjusting for covariates, we found an increased hazard of amputation among individuals in a distressed community (sdHR: 1.25; 95% CI: 1.14, 1.37), which persisted across racial strata. However, regardless of DCI score, Black individuals had the highest incidence of amputation.

Conclusion

Socioeconomic status is independently predictive of limb amputation after controlling for demographic characteristics and clinical comorbidities. Race continues to be an important risk factor, with Black individuals having higher incidence of amputation, even in non-distressed communities, than White individuals had in distressed communities.

Racial disparities in surgical management and outcomes of acute limb ischemia in the United States

Background

Although significant racial disparities in the surgical management of lower extremity critical limb threatening ischemia have been previously reported, data on disparities in lower extremity acute limb ischemia are lacking.

Methods

The 2012–2018 National Inpatient Sample was queried for all adult hospitalizations for acute limb ischemia (N = 225,180). Hospital-specific observed-to-expected rates of major lower extremity amputation were tabulated. Multivariable logistic and linear models were developed to assess the impact of race on amputation and revascularization.

Results

Nonwhite race was associated with significantly increased odds of overall (adjusted odds ratio: 1.16, 95% confidence interval 1.06–1.28) and primary (adjusted odds ratio: 1.34, 95% confidence interval 1.17–1.53) major amputation, decreased odds of revascularization (adjusted odds ratio 0.79, 95% confidence interval 0.73–0.85), but decreased in-hospital mortality (adjusted odds ratio: 0.86, 95% confidence interval 0.74–0.99). The nonwhite group incurred increased adjusted index hospitalization costs (β: +$4,810, 95% confidence interval 3,280-6,350), length of stay (β: + 1.09 days, 95% confidence interval 0.70–1.48), and nonhome discharge (adjusted odds ratio: 1.15, 95% confidence interval 1.06–1.26).

Conclusion

Significant racial disparities exist in the management of and outcomes of lower extremity acute limb ischemia despite correction for variations in hospital amputation practices and other relevant hospital and patient characteristics. Whether the etiology lies primarily in patient, institution, or healthcare provider–specific factors has not yet been determined. Further studies of race-based disparities in management and outcomes of acute limb ischemia are warranted to provide effective and equitable care to all.

Transradial endovascular intervention: Results from the Radial accEss for nAvigation to your CHosen lesion for Peripheral Vascular Intervention (REACH PVI) study

BACKGROUND/PURPOSE

The transradial approach has been proposed as an alternative to traditional transfemoral access for diagnostic and therapeutic purposes in several catheterization procedures. Historically, extended length devices for lower limb endovascular interventions have been limited. The aim of this study was to investigate the acute clinical outcomes of orbital atherectomy (OA) via transradial access (TRA) for the treatment of lower extremity peripheral artery disease (PAD).

METHODS/MATERIALS

REACH PVI was a multicenter, prospective, observational study (NCT03943160) including subjects with PAD and target lesion morphology appropriate for OA. All patients were followed post-procedure through the first standard of care follow-up visit.

RESULTS

A total of 50 patients were enrolled. In most cases the indication for intervention was disabling claudication (74.0%). Overall, 50 target lesions were treated, 92.0% of lesions were femoropopliteal and 8.0% were infrapopliteal. The average lesion length was 98.3 ± 87.5 mm and 78.0% of the lesions were severely calcified. Balloon angioplasty was performed in 98.0% of target lesions, while a stent was deployed in 16.0%. Treatment success was 98.0%; in only one case the result was sub-optimal (>30% stenosis with stent placement) and a significant dissection was reported. No serious distal embolization, serious thrombus formation or serious acute vessel closure were observed intra- or post-procedurally.

CONCLUSIONS

Transradial OA followed by percutaneous transluminal angioplasty for lower extremity PAD is feasible and demonstrates a favorable safety profile. Extended length devices such as the Extended Length Orbital Atherectomy System could further facilitate transradial endovascular procedures by increasing its spectrum of application.

Sex-Related Differences in the Outcomes of Endovascular Interventions for Chronic Limb-Threatening Ischemia: Results from the LIBERTY 360 Study

INTRODUCTION

Previous studies have suggested that women with chroniclimb-threatening ischemia (CLTI) may have worse outcomes than men. The aim of this study was to determine whether there are sex-related differences in outcomes of patients with CLTI undergoing endovascular treatment with current endovascular technologies.

PATIENTS AND METHODS

Data were derived from the LIBERTY 360 study (NCT01855412). Hazard ratios and the respective 95% confidence intervals were synthesized to examine the association between sex and all-cause mortality, target vessel revascularization (TVR), major amputation, major adverse event (MAE) and major amputation/death up to 3 years of follow-up.

RESULTS

A total of 689 patients with CLTI (female: N=252 vs male: N=437) treated with any FDA approved or cleared device were included. The mean lesion length was 126.9±117.3mm and 127.4±113.3mm for the female and male patients, respectively. Although a slightly higher incidence of in-hospital mortality was observed in the female group (1.2% vs 0.0%, p=0.049), there was no difference in female vs male survival rates during follow-up. However, the risk of major amputation at 18 months was higher for the male group (male vs female: HR: 2.36; 95% CI: 1.09-5.12; p=0.030). No difference between the two groups was detected in terms of TVR or MAE during follow-up.

DISCUSSION

Data regarding sex-related disparity in outcomes after endovascular therapy of patients with CLTI are conflicting. Gender-related characteristics rather than biological sex characteristics might be the cause of these conflicting findings. Further studies are needed to evaluate the role of sex in revascularization outcomes among this high-risk population.

Safety and Efficacy of Drug-Coated Balloon Angioplasty for the Treatment of Chronic Limb-Threatening Ischemia: A Systematic Review and Meta-Analysis

Purpose: To investigate the safety and efficacy of drug-coated balloons (DCB) for the treatment of femoropopliteal or infrapopliteal lesions in patients with chronic limb-threatening ischemia (CLTI). Materials and Methods: A systematic literature search was conducted in PubMed, Scopus, and Cochrane Central up to January 2020 to identify randomized trials and observational studies presenting data on the effectiveness and safety of DCBs in the treatment of femoropopliteal or infrapopliteal lesions. A meta-analysis utilizing random effects modeling was conducted to investigate primary patency and all-cause mortality at 12 months; the results are reported as the odds ratios (ORs) and 95% confidence intervals (CIs). Secondary outcomes were procedural success, bailout stenting, target lesion revascularization (TLR), reocclusion, major amputation, wound healing, and major adverse limb events. Results: Twenty-six studies, 12 retrospective and 14 prospective, comprising 2108 CLTI patients treated with DCBs for femoropopliteal (n=1315) or infrapopliteal (n=793) lesions were analyzed. The average lesion lengths were 121±44 and 135±53 mm, respectively. The overall 12-month all-cause mortality and major amputation rates were 9% (95% CI 6% to 13%) and 5% (95% CI 2% to 8%), respectively. Primary patency rates were 82% (95% CI 76% to 87%) and 64% (95% CI 58% to 70%), respectively. A sensitivity analysis of the infrapopliteal lesions demonstrated no difference between DCB and balloon angioplasty in terms of primary patency, TLR, major amputation, or mortality over 12 months. However, patients with infrapopliteal lesions undergoing DCB angioplasty did have a significantly lower risk for reocclusion (10% vs 25%; OR 0.38, 95% CI 0.21 to 0.70, p=0.002). Conclusion: DCB angioplasty of femoropopliteal and infrapopliteal lesions in patients with CLTI results in acceptable 12-month patency rates, although comparative data have not shown a patency benefit for infrapopliteal lesions. The 12-month mortality rate of DCB vs balloon angioplasty was not significantly different, but studies with longer-term outcomes are necessary to determine any association between DCB use and mortality in patients with CLTI.

[Does an attempt to save a limb always prolong the patient's life?]

AIM

The purpose of the study was to examine overall survival and the incidence of major adverse cardiovascular events, as well as economic expenditures for treatment of patients with occlusion of the femoropopliteal-tibial segment and critical ischaemia in low competence of the outflow channel, with a poor prognosis for endovascular or open revascularization of lower-limb arteries.

PATIENTS AND METHODS

We studied the results of treating a total of 68 patients with lower-limb critical ischaemia and low parameters of the outflow channel competence. Primary arterial reconstruction was performed in 48 cases. At various terms after revascularization due to thrombosis of the reconstruction zone and the development of gangrene, amputation of the lower limb was performed: at 3 to 11 (n=25) and at 12 to 24 (n=25) months. Primary amputation of the lower limb was performed in 20 patients. The endpoints of the study included overall survival, the incidence of major adverse cardiovascular events, and economic expenditures for the in-hospital treatment. The average duration of follow-up amounted to 2 years.

RESULTS

The obtained findings demonstrated that in patients with lower-limb critical ischaemia and low parameters of the outflow channel competence, redo arterial reconstructions and amputation within 11 months, as well as a high level of surgical risk were associated with a low overall survival rate and the development of major adverse cardiovascular events in the remote period. Secondary surgical interventions on the major vessels significantly increased the cost of treatment.

One-Year Outcomes of Peripheral Endovascular Device Intervention in Critical Limb Ischemia Patients: Sub-Analysis of the LIBERTY 360 Study

Background

High-risk patients with advanced peripheral artery disease (PAD), including critical limb ischemia (CLI), are often excluded from peripheral endovascular device intervention clinical trials, leading to difficulty in translating trial results into real-world practice. There is a need for prospectively assessed studies to evaluate peripheral endovascular device intervention outcomes in CLI patients.

Methods

LIBERTY 360 is a prospective, observational, multi-center study designed to evaluate the procedural and long-term clinical outcomes of peripheral endovascular device intervention in real-world patients with symptomatic lower-extremity PAD. One thousand two hundred and four patients were enrolled and stratified based on Rutherford Classification (RC): RC2-3 (N=501), RC4-5 (N=603), and RC6 (N=100). For this sub-analysis, RC5 and RC6 patients (RC5-6; N=404) were pooled and 1-year outcomes were assessed.

Results

Procedural complications rarely (1.7%) resulted in post-procedural hospitalization and 89.1% of RC5-6 patients were discharged to home. Considering the advanced disease state in RC5-6 patients, there was a high freedom from 1-year major adverse event rate of 65.5% (defined as target vessel revascularization, death to 30 days, and major target limb amputation). At 1 year, freedom from major amputation was 89.6%. Wounds identified at baseline on the target limb had completely healed in 172/243 (70.8%) of the RC5-6 subjects by 1 year. Additionally, the overall quality of life, as measured by VascuQoL, improved from baseline to 1 year.

Conclusion

LIBERTY investigated real-world PAD patients with independent oversight of outcomes. This analysis of LIBERTY RC5-6 patients demonstrates that peripheral endovascular device intervention can be successful in CLI patients, with low rates of major amputation and improvement in wound healing and quality of life through 1-year follow-up.

LIBERTY 360, https://clinicaltrials.gov/ct2/show/NCT01855412, ClinicalTrials.gov Identifier: NCT01855412.