Team Approach to Critical Limb Ischemia Care and Research

Impact of Kinesiotherapy and Hydrokinetic Therapy on the Rehabilitation of Balance, Gait and Functional Capacity in Patients with Lower Limb Amputation: A Pilot Study

The purpose of this pilot study was to identify impact differences in the rehabilitation of balance, gait and functional capacity in patients with lower limb amputation performing hydrokinetic therapy and kinesiotherapy programs during the pre-prosthetic and prosthetic phases. The study included 16 male patients aged 40–60 years with amputated lower limbs for 6 to 12 months, which involved transfemoral amputation (TFA), transtibial amputation (TTA), traumatic and vascular amputation, who were divided into the following two groups: the hydrokinetic therapy (HKT) group and the kinesiotherapy (KT) group, named after the content of the rehabilitation programs that were implemented for 2 weeks in the pre-prosthetic and prosthetic periods. The initial and final evaluation of the participants included the following tests: the Berg Scale and the four square test for the evaluation of the balance; the PodoSmart device for gait assessment; through the walking test over 6 min, we evaluated the functional capacity. The results were processed in SPSS 24. Analysis of the results on balance rehabilitation through the Berg Scale highlighted that the progress related to the mean of the total score was 7.62 points, p = 0.00 for the HKT group and 7.50 points, p = 0.00 for the KT group, while in the four square step test, the mean of progress was 6.125 s, p = 0.00 for the HKT group and 6 s, p = 0.000 for the KT group. The PodoSmart gait analysis revealed that the HKT group showed a progress mean of 4.875%, p = 0.00, for the foot symmetry parameter, which was 1.875% less than the score achieved by the KT group whose symmetry progress mean was 6.75%, p = 0.00, while the average progress mean for the cadence parameter was 2.75 steps/min higher for the KT group than the HKT group. The comparative analysis of the impact of these two programs on the patients’ functional capacity indicated that the score recorded by the KT group was a progress mean of 15.12 m, p = 0.00 better than the HKT group for the travelled distance parameter; the implementation of the hydrokinetic therapy program led to better exercise adaptation for the HKT group compared to the KT group at an average HR (HRavg) with 0.50 BPM, p = 0.00. After analyzing the results, it has been found that hydrokinetic therapy programs have a greater impact on balance rehabilitation and exercise adaptation, while kinesiotherapy programs have a greater impact on gait rehabilitation and functional capacity optimization for the travelled distance parameter.

Assessment of endothelial colony forming cells delivery routes in a murine model of critical limb threatening ischemia using an optimized cell tracking approach

Background

Endothelial colony forming cells (ECFCs), alone or in combination with mesenchymal stem cells, have been selected as potential therapeutic candidates for critical limb-threatening ischemia (CLTI), mainly for those patients considered as “no-option,” due to their capability to enhance revascularization and perfusion recovery of ischemic tissues. Nevertheless, prior to translating cell therapy to the clinic, biodistribution assays are required by regulatory guidelines to ensure biosafety as well as to discard undesired systemic translocations. Different approaches, from imaging technologies to qPCR-based methods, are currently applied.

Methods

In the current study, we have optimized a cell-tracking assay based on DiR fluorescent cell labeling and near-infrared detection for in vivo and ex vivo assays. Briefly, an improved protocol for DiR staining was set up, by incubation of ECFCs with 6.67 µM DiR and intensive washing steps prior cell administration. The minimal signal detected for the residual DiR, remaining after these washes, was considered as a baseline signal to estimate cell amounts correlated to the DiR intensity values registered in vivo. Besides, several assays were also performed to determine any potential effect of DiR over ECFCs functionality. Furthermore, the optimized protocol was applied in combination with qPCR amplification of specific human Alu sequences to assess the final distribution of ECFCs after intramuscular or intravenous administration to a murine model of CLTI.

Results

The optimized DiR labeling protocol indicated that ECFCs administered intramuscularly remained mainly within the hind limb muscle while cells injected intravenously were found in the spleen, liver and lungs.

Conclusion

Overall, the combination of DiR labeling and qPCR analysis in biodistribution assays constitutes a highly sensitive approach to systemically track cells in vivo. Thereby, human ECFCs administered intramuscularly to CLTI mice remained locally within the ischemic tissues, while intravenously injected cells were found in several organs. Our data corroborate the need to perform biodistribution assays in order to define specific parameters such as the optimal delivery route for ECFCs before their application into the clinic.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02943-8.

Current Status of Angiogenic Cell Therapy and Related Strategies Applied in Critical Limb Ischemia

Critical limb ischemia (CLI) constitutes the most severe form of peripheral arterial disease (PAD), it is characterized by progressive blockade of arterial vessels, commonly correlated to atherosclerosis. Currently, revascularization strategies (bypass grafting, angioplasty) remain the first option for CLI patients, although less than 45% of them are eligible for surgical intervention mainly due to associated comorbidities. Moreover, patients usually require amputation in the short-term. Angiogenic cell therapy has arisen as a promising alternative for these "no-option" patients, with many studies demonstrating the potential of stem cells to enhance revascularization by promoting vessel formation and blood flow recovery in ischemic tissues. Herein, we provide an overview of studies focused on the use of angiogenic cell therapies in CLI in the last years, from approaches testing different cell types in animal/pre-clinical models of CLI, to the clinical trials currently under evaluation. Furthermore, recent alternatives related to stem cell therapies such as the use of secretomes, exosomes, or even microRNA, will be also described.

Improving Limb Salvage for Chronic Limb-Threatening Ischemia With Spinal Cord Stimulation: A Retrospective Analysis

Introduction:

Chronic limb-threatening ischemia (CLTI) represents the most severe form of peripheral artery disease (PAD). Up to a third of CLTI patients are not eligible to receive first-line treatments such as bypass surgery or endovascular interventions. Epidural spinal cord stimulation (SCS) has been used as a method to improve microcirculatory blood flow and relieve ischemic pain in CTLI patients. The aim of the study was to evaluate limb salvage, ulcer closure, and clinical changes of SCS implanted CTLI patients at 1-year follow-up.

Methods:

Eligible patients had end-stage lower limb PAD unresponsive to medical therapy and not amenable to surgical reconstruction. Patients were candidates for amputation, but limb loss was not inevitable (Fontaine stage III and IV). Pain intensity and skin temperature in the ischemic area (visual analogue scale), quality of life (WHOQoL-BREF), and ankle/brachial blood pressure index (ABI) were recorded at routine follow-up visits. Data were analyzed retrospectively.

Results:

29 patients underwent SCS implantation at one vascular center. The minimum follow-up period was 30 months. Limb survival at 1-year follow-up was 97% (28/29) and 73% (11/15) had complete closure of limb ulcers. Pain intensity, skin temperature, and quality of life progressively improved up to 12 months after implant, with Fontaine stage III patients improving more substantially than Fontaine stage IV patients. SCS therapy did not affect ABI measurement. No complications related to the device or procedure occurred.

Conclusions:

SCS is a valid alternative in patients unsuitable for revascularization. The quality of results depends on both a strict selection of patients by vascular specialists and the frequency of follow-up controls. The therapy may be more beneficial in patients classified as Fontaine stage III.

REX-001, a BM-MNC Enriched Solution, Induces Revascularization of Ischemic Tissues in a Murine Model of Chronic Limb-Threatening Ischemia

Background: Bone Marrow Mononuclear Cells (BM-MNC) constitute a promising alternative for the treatment of Chronic Limb-Threatening ischemia (CLTI), a disease characterized by extensive blockade of peripheral arteries, clinically presenting as excruciating pain at rest and ischemic ulcers which may lead to gangrene and amputation. BM-MNC implantation has shown to be efficient in promoting angiogenesis and ameliorating ischemic symptoms in CLTI patients. However, the variability seen between clinical trials makes necessary a further understanding of the mechanisms of action of BM-MNC, and moreover, to improve trial characteristics such as endpoints, inclusion/exclusion criteria or drug product compositions, in order to implement their use as stem-cell therapy.

Materials: Herein, the effect of REX-001, a human-BM derived cell suspension enriched for mononuclear cells, granulocytes and CD34+ cells, has been assessed in a murine model of CLTI. In addition, a REX-001 placebo solution containing BM-derived red blood cells (BM-RBCs) was also tested. Thus, 24 h after double ligation of the femoral artery, REX-001 and placebo were administrated intramuscularly to Balb-c nude mice (n:51) and follow-up of ischemic symptoms (blood flow perfusion, motility, ulceration and necrosis) was carried out for 21 days. The number of vessels and vascular diameter sizes were measured within the ischemic tissues to evaluate neovascularization and arteriogenesis. Finally, several cell-tracking assays were performed to evaluate potential biodistribution of these cells.

Results: REX-001 induced a significant recovery of blood flow by increasing vascular density within the ischemic limbs, with no cell translocation to other organs. Moreover, cell tracking assays confirmed a decrease in the number of infused cells after 2 weeks post-injection despite on-going revascularization, suggesting a paracrine mechanism of action.

Conclusion: Overall, our data supported the role of REX-001 product to improve revascularization and ischemic reperfusion in CLTI.

Outcomes of open and endovascular interventions in patients with chronic limb threatening ischemia

OBJECTIVES

Widespread adoption of endovascular therapy for the treatment of chronic limb-threatening ischemia has transformed the field of vascular surgery. In this modern era, we aimed to define where open surgical interventions are of greatest benefit for limb salvage.

METHODS

Patients who underwent interventions for chronic limb-threatening ischemia were identified in the vascular-targeted lower extremity National Surgical Quality Improvement Program database for open surgical interventions (OPEN) and endovascular surgical interventions (ENDO) from 2011 to 2017. Patients were further stratified based on the criteria of chronic limb-threatening ischemia (rest pain or tissue loss), and the location of the diseased arteries (femoropopliteal or tibioperoneal). The main outcomes measured included 30-day mortality, amputation, and major adverse cardiovascular events.

RESULTS

A total of 17,193 patients were revascularized for chronic limb-threatening ischemia: 10,532 were OPEN and 6661 were ENDO. OPEN had higher 30-day mortality, major adverse cardiovascular events, pulmonary, renal dysfunction, and wound complications. However, OPEN resulted in significantly lower 30-day major amputation (3.8% vs. 5.0%, odds ratio (OR): 0.83 [0.72-0.97], P = .018). Subgroup analysis revealed a higher mortality rate in OPEN was observed only in tibioperoneal intervention for tissue loss. Major adverse cardiovascular event was higher in OPEN for most subgroups. OPEN for patients with tissue loss had significantly lower amputation rate than ENDO in both femoropopliteal and tibioperoneal subgroups (3.7% vs. 5.1%, OR: 0.76 [0.59-0.98], P = .036, and 4.7% vs. 6.6%, OR: 0.74 [0.57-0.96], P = .024, respectively). The benefit of open surgery in reducing the amputation rate was not seen in patients with rest pain.

CONCLUSIONS

Open surgical intervention is associated with significantly better limb salvage than endovascular intervention in patients with tissue loss. Surgical options should be given more emphasis as the first-line option in this cohort of patients unless the cardiopulmonary risk is prohibitive.

Multidisciplinary Heart Team Approach for Complex Coronary Artery Disease: Single Center Clinical Presentation

Background The Heart Team approach is ascribed a Class I recommendation in contemporary guidelines for revascularization of complex coronary artery disease. However, limited data are available regarding the decision-making and outcomes of patients based on this strategy. Methods and Results One hundred sixty-six high-risk coronary artery disease patients underwent Heart Team evaluation at a single institution between January 2015 and November 2018. We prospectively collected data on demographics, symptoms, Society of Thoracic Surgeons Predicted Risk of Mortality/Synergy Between PCI with Taxus and Cardiac Surgery (STS-PROM/SYNTAX) scores, mode of revascularization, and outcomes. Mean age was 70.0 years; 122 (73.5%) patients were male. Prevalent comorbidities included diabetes mellitus (51.8%), peripheral artery disease (38.6%), atrial fibrillation (27.1%), end-stage renal disease on dialysis (13.3%), and chronic obstructive pulmonary disease (21.7%). Eighty-seven (52.4%) patients had New York Heart Association III-IV and 112 (67.5%) had Canadian Cardiovascular Society III-IV symptomatology. Sixty-seven (40.4%) patients had left main and 118 (71.1%) had 3-vessel coronary artery disease. The median STS-PROM was 3.6% (interquartile range 1.9, 8.0) and SYNTAX score was 26 (interquartile range 20, 34). The median number of physicians per Heart Team meeting was 6 (interquartile range 5, 8). Seventy-nine (47.6%) and 49 (29.5%) patients underwent percutaneous coronary intervention and coronary artery bypass grafting, respectively. With increasing STS-PROM (low, intermediate, high operative risk), coronary artery bypass graft was performed less often (47.9%, 18.5%, 15.2%) and optimal medical therapy was recommended more often (11.3%, 18.5%, 30.3%). There were no trends in recommendation for coronary artery bypass graft, percutaneous coronary intervention, or optimal medical therapy by SYNTAX score tertiles. In-hospital and 30-day mortality was 3.9% and 4.8%, respectively. Conclusions Integrating a multidisciplinary Heart Team into institutional practice is feasible and provides a formalized approach to evaluating complex coronary artery disease patients. The comprehensive assessment of surgical, anatomical, and other risk scores using a decision aid may guide appropriate, evidence-based management within this team-based construct.

Peripheral interventions and antiplatelet therapy: Role in current practice

Peripheral arterial disease (PAD) is a common disorder associated with a high risk of cardiovascular mortality and continues to be under-recognized. The major risk factors for PAD are similar to those for coronary and cerebrovascular disease. Management includes exercise program, pharmacologic therapy and revascularization including endovascular and surgical approach. The optimal revascularization strategy, endovascular or surgical intervention, is often debated due to the paucity of head to head randomized controlled studies. Despite significant advances in endovascular interventions resulting in increased utilization over surgical bypass, significant challenges still remain. Platelet activation and aggregation after percutaneous transluminal angioplasty of atherosclerotic arteries are important risk factors for re-occlusion/restenosis and life-threatening thrombosis following endovascular procedures. Antiplatelet agents are commonly prescribed to reduce the risk of myocardial infarction, stroke and death from cardiovascular causes in patients with PAD. Despite an abundance of data demonstrating efficacy of antiplatelet therapy in coronary artery disease and cerebrovascular disease, there is a paucity of clinical information, clinical guidelines and randomized controlled studies in the PAD population. Hence, data on antiplatelet therapy in coronary interventions is frequently extrapolated to peripheral interventions. The aim of this review article is to elucidate the current data on revascularization and the role and duration of antiplatelet and anticoagulant therapy in re-vascularized lower limb PAD patients.