Management of Critical Limb Ischemia

The association of chronic obstructive pulmonary disease and 30-day outcomes of infrainguinal bypass surgery: A propensity-score matching study

BACKGROUND

Infrainguinal bypass surgery is an effective treatment for peripheral artery disease (PAD). While chronic obstructive pulmonary disease (COPD) has been linked to heightened risks of mortality and morbidity in major surgery, a thorough investigation into COPD's impact on infrainguinal bypass outcomes remained underexplored. Thus, this study aimed to assess the 30-day outcomes for COPD patients undergoing infrainguinal bypass surgery.

METHODS

COPD and non-COPD patients who underwent infrainguinal bypass were identified in American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2011 to 2022. Patients of age<18 were excluded. A 1:1 propensity-score matching was used to match demographics, baseline characteristics, symptomatology, procedure, conduit, and anesthesia. Thirty postoperative outcomes were compared.

RESULTS

There were 3,183 (12.64%) and 22,004 (87.36%) patients with and without COPD, respectively, who underwent infrainguinal bypass. COPD patients had a higher comorbid burden. After propensity-score matching, COPD patients had higher sepsis (3.55% vs 2.42%, p = 0.01), wound complications (18.94% vs 16.40%, p = 0.01), and 30-day readmission (18.00% vs 14.92%, p < 0.01). However, COPD and non-COPD patients had comparable 30-day mortality (2.54% vs 2.67%, p = 0.81), and organ system complications including cardiac (3.58% vs 3.99%, p = 0.43), pulmonary (3.96% vs 3.20%, p = 0.12), and renal complications (1.70% vs 1.82%, p = 0.78). Limb-specific outcomes including major amputation (2.95% vs 2.50%, p = 0.30), untreated loss of patency (1.85% vs 1.38%, p = 0.16), and patent graft (98.24% vs 98.65%, p = 0.27) were also comparable between the cohorts.

CONCLUSION

While COPD might be associated with the development of PAD due to potentially shared pathophysiology, it may not be an independent risk factor for the major 30-day outcomes in infrainguinal bypass surgery.

Deletion of endothelial IGFBP5 protects against ischaemic hindlimb injury by promoting angiogenesis

BACKGROUND

Angiogenesis is critical for forming new blood vessels from antedating vascular vessels. The endothelium is essential for angiogenesis, vascular remodelling and minimisation of functional deficits following ischaemia. The insulin-like growth factor (IGF) family is crucial for angiogenesis. Insulin-like growth factor-binding protein 5 (IGFBP5), a binding protein of the IGF family, may have places in angiogenesis, but the mechanisms are not yet completely understood. We sought to probe whether IGFBP5 is involved in pathological angiogenesis and uncover the molecular mechanisms behind it.

METHODS AND RESULTS

IGFBP5 expression was elevated in the vascular endothelium of gastrocnemius muscle from critical limb ischaemia patients and hindlimb ischaemic (HLI) mice and hypoxic human umbilical vein endothelial cells (HUVECs). In vivo, loss of endothelial IGFBP5 (IGFBP5EKO) facilitated the recovery of blood vessel function and limb necrosis in HLI mice. Moreover, skin damage healing and aortic ring sprouting were faster in IGFBP5EKO mice than in control mice. In vitro, the genetic inhibition of IGFBP5 in HUVECs significantly promoted tube formation, cell proliferation and migration by mediating the phosphorylation of IGF1R, Erk1/2 and Akt. Intriguingly, pharmacological treatment of HUVECs with recombinant human IGFBP5 ensued a contrasting effect on angiogenesis by inhibiting the IGF1 or IGF2 function. Genetic inhibition of IGFBP5 promoted cellular oxygen consumption and extracellular acidification rates via IGF1R-mediated glycolytic adenosine triphosphate (ATP) metabolism. Mechanistically, IGFBP5 exerted its role via E3 ubiquitin ligase Von Hippel-Lindau (VHL)-regulated HIF1α stability. Furthermore, the knockdown of the endothelial IGF1R partially abolished the reformative effect of IGFBP5EKO mice post-HLI.

CONCLUSION

Our findings demonstrate that IGFBP5 ablation enhances angiogenesis by promoting ATP metabolism and stabilising HIF1α, implying IGFBP5 is a novel therapeutic target for treating abnormal angiogenesis-related conditions.

Utility of the ACD-GENE-CLI Score in Asian Patients with Critical Limb Ischemia Undergoing Endovascular Interventions

AIMS

Critical limb ischemia (CLI) is an emerging public health threat and lacks a reliable score for predicting the outcomes. The Age, Body Mass Index, Chronic Kidney Disease, Diabetes, and Genotyping (ABCD-GENE) risk score helps identify patients with coronary artery disease who have cytochrome P450 2C19 (CYP2C19) polymorphism-related drug resistance and are at risk for cardiovascular adverse events. However, its application to CLI remains unknown. In this study, we aim to validate a modified ACD-GENE-CLI score to improve the prediction of major adverse limb events (MALEs) in patients with CLI receiving clopidogrel.

METHODS

Patients with CLI receiving clopidogrel post-endovascular intervention were enrolled prospectively in two medical centers. Amputation and revascularization as MALEs were regarded as the outcomes.

RESULTS

A total of 473 patients were recruited, with a mean follow-up duration of 25 months. Except for obesity, old age, diabetes, chronic kidney disease (CKD), and CYP2C19 polymorphisms were significantly associated with MALEs. Using bootstrap regression analysis, we established a modified risk score (ACD-GENE-CLI) that included old age (≥ 65 years), diabetes, CKD, and CYP2C19 polymorphisms. At a cutoff value of 8, the ACD-GENE-CLI score was superior to the CYP2C19 deficiency only, and the conventional ABCD-GENE score in predicting MALEs (area under the curve: 0.69 vs. 0.59 vs. 0.67, p=0.01). The diagnostic ability of the ACD-GENE-CLI score was consistent in the external validation. Also, Kaplan-Meier curves showed that in CYP2C19 deficiency, the ABCD-GENE and ACD-GENE-CLI scores could all differentiate patients with CLI who are free from MALEs.

CONCLUSIONS

The modified ACD-GENE-CLI score could differentiate patients with CLI receiving clopidogrel who are at risk of MALEs. Further studies are required to generalize the utility of the score.

Emerging trends in nationwide mortality, limb loss, and resource utilization for critical limb ischemia in young adults

BACKGROUND/OBJECTIVES

Recent trends indicate a rise in the incidence of critical limb ischemia (CLI) among younger adults. This study examines trends in CLI hospitalization and outcomes among young adults with peripheral arterial disease (PAD) in the United States.

METHODS

Adult hospitalizations (18-40 years) for PAD/CLI were analyzed from the 2016-2020 nationwide inpatient sample database using ICD-10 codes. Rates were reported per 1000 PAD or 100,000 cardiovascular disease admissions. Outcomes included trends in mortality, major amputations, revascularization, length of hospital stay (LOS), and hospital costs (THC). We used the Jonckheere-Terpstra tests for trend analysis and adjusted costs to the 2020 dollar using the consumer price index.

RESULTS

Approximately 63,045 PAD and 20,455 CLI admissions were analyzed. The mean age of the CLI cohort was 32.7 ± 3 years. The majority (12,907; 63.1 %) were female and white (11,843; 57.9 %). Annual CLI rates showed an uptrend with 3265 hospitalizations (227 per 1000 PAD hospitalizations, 22.7 %) in 2016 to 4474 (252 per 1000 PAD hospitalizations, 25.2 %) in 2020 (Ptrend<0.001), along with an increase in PAD admissions from 14,405 (188 per 100,000, 0.19 %) in 2016 to 17,745 (232 per 100,000, 0.23 %%) in 2020 (Ptrend<0.0001). Annual in-hospital mortality increased from 570 (2.8 %) in 2016 to 803 (3.9 %) in 2020 (Ptrend = 0.001) while amputations increased from 1084 (33.2 %) in 2016 to 1995 (44.6 %) in 2020 (Ptrend<0.001). Mean LOS increased from 5.1 (SD 2.7) days in 2016 to 6.5 (SD 0.9) days in 2020 (Ptrend = 0.002). The mean THC for CLI increased from $50,873 to $69,262 in 2020 (Ptrend<0.001). The endovascular revascularization rates decreased from 11.5 % (525 cases) in 2016 to 10.7 % (635 cases) in 2020 (Ptrend = 0.025). Surgical revascularization rates also increased from 4.9 % (225 cases) in 2016 to 10.4 % (600 cases) in 2020 (Ptrend = 0.041).

CONCLUSION

Hospitalization and outcomes for CLI worsened among young adults during the study period. There is an urgent need to enhance surveillance for risk factors of PAD in this age group.

The relationship between hyperpolypharmacy and one-year outcomes in patients with critical limb ischemia undergoing below-knee endovascular therapy

BACKGROUND

Critical limb ischemia (CLI) patients take too many medications because they are elderly and frail patients with multiple comorbidities. Polypharmacy is associated with frailty, although its prognostic significance in CLI patients is unknown. In this study, we aimed to determine the prevalence of hyperpolypharmacy among adults with CLI and its effect on 1-year amputation and mortality.

METHODS

A total of 200 patients with CLI who underwent endovascular therapy (EVT) for below-knee (CTC) lesions were included in this study. Hyperpolypharmacy was defined as using ≥10 drugs. Patients were divided into two groups according to the presence of hyperpolypharmacy.

RESULTS

We detected hyperpolypharmacy in 66 patients. The incidence of 1-year amputation [24 (36.4) versus 12 (9), p<.001] and mortality [28 (42.4) versus 12 (9), p<.001] were higher in patients with hyperpolypharmacy. Univariate and multivariate cox regression analyses were used to determine the independent predictors of amputation and mortality. In the receiver operating characteristic curve analysis, the cut-off value was defined as 10 or more drug use was able to detect the presence of 1-year mortality with 67.5% sensitivity and 79.4% specificity. The Kaplan-Meier method showed a significant difference (rank p <.001 between log groups), and hyperpolypharmacy was associated with 1-year amputation and mortality.

CONCLUSION

Hyperpolypharmacy was significantly associated with 1-year mortality and major amputation in CLI patients. Hyperpolypharmacy can be a valuable aid in patient risk assessment in the CLI.

Assessment of Efficacy and Complications of Endovascular Interventions for Critical Limb Ischemia in Germany: A Nationwide Study

PURPOSE

 Endovascular interventional radiological procedures have become the mainstay for the treatment of critical limb ischemia (CLI) due to arterial stenosis or occlusion. Open surgical or endovascular procedures, such as percutaneous transluminal angioplasty (PTA) or stenting can be used as a treatment strategy. The aim is to evaluate the success and major complication rates of interventional radiology treatments for CLI in Germany in 2021, and to compare these results with internationally published data.

MATERIALS AND METHODS

 Data for PTA and stenting in CLI for 2021 was obtained from the quality management system of the German Society of Interventional Radiology (DeGIR). 16 393 PTA procedures, 701 stenting procedures, and 8110 combined procedures were documented for 2021. Data was analyzed for technical and clinical success rates, as well as major complication rates documented mainly as major bleeding, distal embolization, and aneurysm formation.

RESULTS

 PTA had technical and clinical success rates of 96.3 % and 92.33 %, respectively. Stenting had technical and clinical success rates of 98.7 % and 96.15 %, respectively. PTA and stenting combined had success rates of 98.71 % and 96.91 %, respectively. The major complications were mainly: major bleeding (PTA: 0.40 %; stenting: 1.28 %; PTA and stenting: 0.54 %), distal embolization (PTA: 0.48 %; stenting: 1 %; PTA and stenting: 0.96 %), and aneurysm formation (PTA: 0.19 %; stenting: 0.43 %; PTA and stenting: 0.19 %). All procedures showed high technical and clinical success rates, while the complication rates were low.

CONCLUSION

 Interventional radiologists in Germany perform effective and safe treatment for CLI, achieving outcomes that tend to surpass internationally published data.

KEY POINTS

  · German interventional radiologists provide safe and effective critical limb ischemia treatment.. · Major complications occurred at maximum in 1.28 % of cases.. · Outcomes tend to surpass international data, indicating strong performance..

The comparison of adipose-derived stromal cells (ADSCs) delivery method in a murine model of hindlimb ischemia

BACKGROUND

Adipose-derived stromal cells (ADSCs) demonstrate ability to promote tissue healing and down-regulate excessive inflammation. ADSCs have been used to treat critical limb ischemia in preclinical and clinical trials, but still, there is little known about their optimal delivery strategy. To date, no direct analysis of different methods of ADSCs delivery has been performed in the hindlimb ischemia model. Therefore, in this study we focused on the therapeutic efficacy of different ADSCs delivery methods in a murine model of hindlimb ischemia.

METHODS

For the hADSCs isolation, we used the subcutaneous adipose tissue collected during the surgery. The murine hindlimb ischemia was used as a model. The unilateral femoral artery ligation was performed on 10-12-week-old male C57BL/6. ADSCs were delivered directly into ischemic muscle, into the contralateral muscle or intravenously. 7 and 14 days after the surgery, the gastrocnemius and quadriceps muscles were collected for the immunohistochemical analysis. The results were analyzed with relevant tests using the Statistica software.

RESULTS

Our research revealed that muscle regeneration, angiogenesis, arteriogenesis and macrophage infiltration in murine model of hindlimb ischemia differ depending on ADSCs delivery method. We have demonstrated that intramuscular method (directly into ischemic limb) of ADSCs delivery is more efficient in functional recovery after critical limb ischemia than intravenous or contralateral route.

CONCLUSIONS

We have noticed that injection of ADSCs directly into ischemic limb is the optimal delivery strategy because it increases: (1) muscle fiber regeneration, (2) the number of capillaries and (3) the influx of macrophages F4/80+/CD206+.

Lower limb revascularization leads to faster walking but with less efficient mechanics in claudicating patients

Peripheral artery disease (PAD) is characterized by reduced blood flow to the extremities due to atherosclerosis. Studies report impaired gait mechanics in patients with lower extremity PAD. We hypothesized that revascularization surgery would improve gait mechanics when quantified by net lower limb joint work across the stance phase of walking. We performed gait analyses in 35 patients with PAD and 35 healthy, older adults. Patients with PAD performed a walking protocol prior to and six months following revascularization surgery. Healthy adults only took part in a single walking session. Lower limb joint powers were calculated using inverse dynamics and were integrated across early, middle, and late stance phases to determine the work performed during each phase (J kg-1). The work mechanical ratio between positive-producing and negative-producing phases of stance was calculated for each lower-limb joint. Self-selected walking speed significantly increased from 1.13 ± 0.2 ms-1 to 1.26 ± 0.18 ms-1 in patients following revascularization (p < 0.001). We observed a significant decrease in positive late stance work (p < 0.001) in conjunction with more negative work during early stance (p < 0.001) in patients following revascularization. Revascularization surgery led to faster walking without an increase in the ankle joint's mechanical ratio. Our results suggest faster walking was achieved via work done at the hip rather than the ankle. These findings suggest that additional therapies that facilitate the restoration of muscle, tissue, and nervous system damage caused by years of having reduced blood flow to the limbs might still be beneficial following revascularization.

Growth factor free, peptide-functionalized gelatin hydrogel promotes arteriogenesis and attenuates tissue damage in a murine model of critical limb ischemia

Critical limb ischemia (CLI) occurs when blood flow is restricted through the arteries, resulting in ulcers, necrosis, and chronic wounds in the downstream extremities. The development of collateral arterioles (i.e. arteriogenesis), either by remodeling of pre-existing vascular networks or de novo growth of new vessels, can prevent or reverse ischemic damage, but it remains challenging to stimulate collateral arteriole development in a therapeutic context. Here, we show that a gelatin-based hydrogel, devoid of growth factors or encapsulated cells, promotes arteriogenesis and attenuates tissue damage in a murine CLI model. The gelatin hydrogel is functionalized with a peptide derived from the extracellular epitope of Type 1 cadherins. Mechanistically, these "GelCad" hydrogels promote arteriogenesis by recruiting smooth muscle cells to vessel structures in both ex vivo and in vivo assays. In a murine femoral artery ligation model of CLI, delivery of in situ crosslinking GelCad hydrogels was sufficient to restore limb perfusion and maintain tissue health for 14 days, whereas mice treated with gelatin hydrogels had extensive necrosis and autoamputated within 7 days. A small cohort of mice receiving the GelCad hydrogels were aged out to 5 months and exhibited no decline in tissue quality, indicating durability of the collateral arteriole networks. Overall, given the simplicity and off-the-shelf format of the GelCad hydrogel platform, we suggest it could have utility for CLI treatment and potentially other indications that would benefit from arteriole development.

Animal experimental models of ischemic limbs - A systematic review

BACKGROUND

The objective of this systematic review is to summarize the available animal models of ischemic limbs, and to provide an overview of the advantages and disadvantages of each animal model and individual method of limb ischemia creation.

METHODS

A review of literature was conducted using the PubMed and Web of Science pages. Various types of experimental animals and surgical approaches used in creating ischemic limbs were evaluated. Other outcomes of interest were the specific characteristics of the individual experimental animals, and duration of tissue ischemia.

RESULTS

The most commonly used experimental animals were mice, followed by rabbits, rats, pigs, miniature pigs, and sheep. Single or double arterial ligation and excision of the entire femoral artery was the most often used method of ischemic limb creation. Other methods comprised single or double arterial electrocoagulation, use of ameroid constrictors, photochemically induced thrombosis, and different types of endovascular methods. The shortest duration of tissue ischemia was 7 days, the longest 90 days.

CONCLUSIONS

This review shows that mice are among the most commonly used animals in limb ischemia research. Simple ligation and excision of the femoral artery is the most common method of creating an ischemic limb; nevertheless, it can result in acute rather than chronic ischemia. A two-stage sequential approach and methods using ameroid constrictors or endovascular blinded stent grafts are more suitable for creating a gradual arterial occlusion typically seen in humans. Selecting the right mouse strain or animal with artificially produced diabetes or hyperlipidaemia is crucial in chronic ischemic limb research. Moreover, the observation period following the onset of ischemia should last at least 14 days, preferably 4 weeks.

Predictive Factors for Limb Salvage and Foot Ulcer Recurrence in Patients with Chronic Limb-Threatening Ischemia After Multidisciplinary Team Treatment: A 6-Year Japanese Single-Center Study

Chronic limb-threatening ischemia (CLTI) is associated with a short-term risk of limb loss. Multidisciplinary teams are often involved in CLTI treatment; however, in Asian countries, multidisciplinary teams that include podiatrists specializing in foot wounds and vascular surgeons who can perform distal bypass surgery are lacking. We investigated predictive factors for limb salvage and foot ulcer recurrence in patients with CLTI treated by a Japanese single-center intensive multidisciplinary team over 6 years. We retrospectively investigated 84 patients with CLTI and foot ulcers who had undergone revascularization and wound treatment between October 2013 and December 2019. Following postrevascularization treatment, including undertaking minor amputations, the healing rate was 77.8%, and the average wound healing time was 75 ± 68 days. To achieve adequate blood supply, 17.7% of patients were treated using a combination of endovascular revascularization and bypass surgeries. Thirty-three (44%) patients had wound recurrence and there was wound recurrence within 6 months in 58.9% of these patients. Multivariate logistic regression analysis showed that postrevascularization skin perfusion pressure was significantly associated with wound healing (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.033-1.243, P = .0078). Diabetes mellitus (OR 9.72, 95% CI 1.855-50.937, P = .0071), and heart disease (OR 3.51, 95% CI 1.052-11.693, P = .0411) were significantly associated with wound recurrence (P < .05). Treatment within a single-center intensive multidisciplinary team resulted in good patient outcomes. Our study indicates that the revascularization endpoint of CLTI treatment should be marked by attainment of adequate blood supply and wound healing. The timing of revascularization and debridement is of utmost importance for the successful treatment of CLTI wounds.

Understanding Gangrene in the Context of Peripheral Vascular Disease: Prevalence, Etiology, and Considerations for Amputation-Level Determination

Gangrene is a grave complication of peripheral vascular disease (PVD), characterised by tissue necrosis due to inadequate blood supply. This review article comprehensively explores gangrene in PVD, encompassing its prevalence, aetiology, clinical presentation, diagnostic modalities, management strategies, prognosis, and future directions. Key factors influencing outcomes, including the timeliness of intervention and the choice between limb salvage and amputation, are identified. Moreover, this review underscores the importance of early detection and multidisciplinary care, emphasising the significance of patient-centred approaches. It also calls for increased awareness, continued research, and innovative solutions to improve the lives of individuals grappling with gangrene in the context of PVD.

Predictors of Recurrent Venous Thromboembolism or Arterial Thrombotic Events during and after Anticoagulation for a First Venous Thromboembolism

After first episodes of venous thromboembolism (VTE), patients are at increased risk of recurrent VTE and arterial thrombotic events (ATE) compared with the general population, two disorders that are influenced by anticoagulation. However, risk factors of these conditions occurring during and after anticoagulation are little described. Using cause-specific hazard regression models, we aimed to determine risk factors of the composite outcome recurrent VTE/ATE, and separately recurrent VTE or ATE, during and after anticoagulation in patients with first episodes of VTE from a prospective cohort. Hazard ratios (HRs) are given with 95% confidence intervals (CIs). A total of 2,011 patients treated for at least 3 months were included. A total of 647 patients had recurrent VTE/ATE (incidence: 4.69% per patient-years) during overall follow-up (median: 92 months). Of these events, 173 occurred during anticoagulation (incidence: 3.67% per patient-years). Among patients free of events at the end of anticoagulation, 801 had a post-anticoagulation follow-up ≥3 months; and 95 had recurrent VTE/ATE (incidence: 1.27% per patient-years). After adjustment for confounders, cancer-associated VTE (HR: 2.64, 95% CI: 1.70-4.11) and unprovoked VTE (HR: 1.95, 95% CI: 1.35-2.81) were the identified risk factors of recurrent VTE/ATE during anticoagulation (vs. transient risk factor-related VTE). Risk factors of recurrent VTE/ATE after anticoagulation included 50 to 65 years of age (vs. < 50, HR: 1.99, 95% CI: 1.04-3.81), older than 65 years (vs. < 50, HR: 5.28, 95% CI: 3.03-9.21), and unprovoked VTE (vs. transient risk factor-related VTE, HR: 2.06, 95% CI: 1.27-3.34). Cancer-associated VTE and unprovoked VTE are the main risk factors of recurrent VTE/ATE during anticoagulation, while older age and unprovoked VTE mainly predict the risk of these events after anticoagulation.

Obesity and Peripheral Artery Disease: Current Evidence and Controversies

PURPOSE OF REVIEW

Obesity is a significant public health problem and a major risk factor for the development and progression of atherosclerosis and its cardiovascular manifestations. Lower extremity peripheral artery disease (PAD) affects 3%-10% of the Western population and, if left untreated, can lead to devastating outcomes with both an increased risk of morbidity and mortality. Interestingly, the association between obesity and PAD remains debatable. Whereas it is well known that PAD and obesity frequently overlap in the same patients, many studies have demonstrated a negative association between obesity and PAD and a protective effect of obesity on disease development and progression, a phenomenon described as the "obesity paradox." Possible mechanisms for this paradox may include genetic background, as assessed by mendelian randomization studies, adipose tissue dysfunction, and body fat distribution rather than adiposity, while other factors, such as sex, ethnicity, sarcopenia in the elderly population, or aggressive treatment of co-existing metabolic conditions in individuals with obesity compared to those with normal weight, could have some impact as well.

RECENT RINDINGS

Few reviews and meta-analyses examining systematically the relationship between obesity and PAD exist. The impact of PAD development due to the presence of obesity remains largely controversial. However, the most current evidence, backed by a recent meta-analysis, suggests a potential protective role of a higher body mass index on PAD-related complications and mortality. In this review, we discuss the association between obesity and PAD development, progression, and management, and the potential pathophysiologic mechanisms linking the two diseases.

A biomaterial-based therapy for lower limb ischemia using Sr/Si bioactive hydrogel that inhibits skeletal muscle necrosis and enhances angiogenesis

Muscle necrosis and angiogenesis are two major challenges in the treatment of lower-limb ischemic diseases. In this study, a triple-functional Sr/Si-containing bioceramic/alginate composite hydrogel with simultaneous bioactivity in enhancing angiogenesis, regulating inflammation, and inhibiting muscle necrosis was designed to treat lower-limb ischemic diseases. In particular, sodium alginate, calcium silicate and strontium carbonate were used to prepare injectable hydrogels, which was gelled within 10 min. More importantly, this composite hydrogel sustainedly releases bioactive Sr²⁺ and SiO₃ ^2- ions within 28 days. The biological activity of the bioactive ions released from the hydrogels was verified on HUVECs, SMCs, C2C12 and Raw 264.7 cells in vitro, and the therapeutic effect of the hydrogel was confirmed using C57BL/6 mouse model of femoral artery ligation in vivo. The results showed that the composite hydrogel stimulated angiogenesis, developed new collateral capillaries, and re-established the blood supply. In addition, the bioactive hydrogel directly promoted the expression of muscle-regulating factors (MyoG and MyoD) to protect skeletal muscle from necrosis, inhibited M1 polarization, and promoted M2 polarization of macrophages to reduce inflammation, thereby protecting skeletal muscle cells and indirectly promoting vascularization. Our results indicate that these bioceramic/alginate composite bioactive hydrogels are effective biomaterials for treating hindlimb ischemia and suggest that biomaterial-based approaches may have remarkable potential in treating ischemic diseases.

Chronic Limb-Threatening Ischemia in Patients with Type 2 Diabetes: Revascularization Index as a Predictor for Primary Endovascular Intervention Outcome

Purpose

Chronic limb-threatening ischemia in patients with diabetes is associated with a high risk of adverse outcomes. The associated co-morbidities, the heterogeneity of foot presentation and the distribution of atherosclerotic lesions led to the emergence of multiple revascularization strategies and scoring systems to improve management outcomes. This study aimed to introduce a new index, the revascularization index (RI), and to assess its predictive value for the outcomes of primary endovascular intervention in patients with type 2 diabetes presenting with chronic limb-threatening ischemia.

Patients and Methods

A retrospective electronic medical records review was conducted for patients with type 2 diabetes presenting with chronic limb-threatening ischemia managed at King Abdullah University Hospital by primary endovascular interventions between January 2014 and August 2019. The RI was analyzed for its predictive value for the treatment outcomes.

Results

A total of 187 patients were included in this study, with a major lower limb amputation rate of 19.3%. The performance of the RI was excellent in predicting secondary revascularization (AUC = 0.80, 95% CI: 0.73-0.86, p-value < 0.001), good to predict major amputation (AUC = 0.76, 95% CI: 0.67-0.85, p-value = 0.047), and poor in predicting death (AUC = 0.46, 95% CI: 0.40-0.55, p-value = 0.398). RI of <1.21 was significantly associated with a higher risk of major lower limb amputation (HR = 5.8, 95% CI: 1.25-26.97, p-value < 0.025), and RI of < 1.3 was associated with a higher risk for secondary revascularization.

Conclusion

The RI can be used to predict major adverse lower limb events (MALE). It might be used as a guide for the extent of endovascular interventions for diabetic chronic limb-threatening ischemia with multi-level outflow atherosclerotic disease.

Stem Cell Therapy in Critical Limb Ischemia

Critical limb ischemia (CLI), a serious outcome of peripheral artery disease, is frequently associated with morbid outcomes. The available treatment modalities do not provide satisfactory results, leading to marked morbidities such as joint contracture and amputations, resulting in a high economic burden. The peripheral vascular disease tends to cause more morbidity in patients with diabetes and atherosclerosis, given the pre-existing compromised perfusion of medium and small vessels in diabetic patients. With surgical procedures, the chance of vascular compromise further increases, inducing a significantly greater rate of amputation. Hence, the need for nonsurgical treatment modalities such as stem cell therapy (SCT), which promotes angiogenesis, is warranted. In CLI, SCT acts through neovascularization and the development of collateral arteries, which increases blood supply to the soft tissues of the ischemic limb, providing satisfactory outcomes. An electronic database search was performed in PubMed, SCOPUS, EMBASE, and ScienceDirect to identify published clinical trial data, research studies, and review articles on stem cell therapy in critical limb ischemia. The search resulted in a total of 2391 results. Duplicate articles screening resulted in 565 articles. In-depth screening of abstracts and research titles excluded 520 articles, yielding 45 articles suitable for full-text review. On review of full text, articles with overlapping and similar results were filtered, ending in 25 articles. SCT promotes arteriogenesis, and bone marrow-derived mesenchymal stromal cells produce significant effects like reduced morbidity, improved amputation-free survival (AFS ) rate, and improved distal perfusion even in "no-option" CLI patients. SCT is a promising treatment modality for CLI patients, even in those in whom endovascular and revascularization procedures are impossible. SCT assures a prolonged AFS rate, improved distal perfusion, improved walking distances, reduced amputation rates, and increased survival ratio, and is well-tolerated.

Growth factor-free, peptide-functionalized gelatin hydrogel promotes arteriogenesis and attenuates tissue damage in a murine model of critical limb ischemia

Critical limb ischemia (CLI) occurs when blood flow is restricted through the arteries, resulting in ulcers, necrosis, and chronic wounds in the downstream extremities. The development of collateral arterioles (i.e. arteriogenesis), either by remodeling of pre-existing vascular networks or de novo growth of new vessels, can prevent or reverse ischemic damage, but it remains challenging to stimulate collateral arteriole development in a therapeutic context. Here, we show that a gelatin-based hydrogel, devoid of growth factors or encapsulated cells, promotes arteriogenesis and attenuates tissue damage in a murine CLI model. The gelatin hydrogel is functionalized with a peptide derived from the extracellular epitope of Type 1 cadherins. Mechanistically, these "GelCad" hydrogels promote arteriogenesis by recruiting smooth muscle cells to vessel structures in both ex vivo and in vivo assays. In a murine femoral artery ligation model of CLI, delivery of in situ crosslinking GelCad hydrogels was sufficient to restore limb perfusion and maintain tissue health for 14 days, whereas mice treated with gelatin hydrogels had extensive necrosis and autoamputated within 7 days. A small cohort of mice receiving the GelCad hydrogels were aged out to 5 months and exhibited no decline in tissue quality, indicating durability of the collateral arteriole networks. Overall, given the simplicity and off-the-shelf format of the GelCad hydrogel platform, we suggest it could have utility for CLI treatment and potentially other indications that would benefit from arteriole development.

Posterior Approach to the Popliteal to Peroneal Bypass

Critical limb ischemia (CLI) is a clinical syndrome related to peripheral artery disease (PAD) that is marked by ischemic rest pain or tissue loss such as nonhealing ulcers or gangrene. Without revascularization CLI carries a 30-50% risk of major limb amputation within 1 year. Initial surgical revascularization is recommended for patients with CLI who have a greater than 2-year life expectancy. We present the case of a 92-year-old male with severe peripheral artery disease with gangrene of bilateral toes who underwent right popliteal to distal peroneal bypass via the posterior approach using ipsilateral reversed GSV. The posterior approach provides excellent exposure and should be considered in distal surgical revascularization where the popliteal artery serves as inflow and distal peroneal artery as target outflow vessel.

A phantom study: Evaluation of a novel three-lumen balloon catheter for potential treatment of intractable limb ischemia

Critical limb ischemia (CLI) is the most severe form of peripheral arterial disease (PAD) which induces extremity rest pain, extremity gangrene or ulcers that mostly might lead to limb loss. One of the most common criteria of CLI is 50 mmHg or less systolic ankle arterial pressure. In this study, a custom made three-lumen catheter (9 Fr) including a distal inflatable balloon in between the inflow and outflow lumen holes was designed and fabricated based on the patented design of Hyper Perfusion Catheter. The proposed catheter design aims to increase ankle systolic pressure to 60 mmHg or more to promote healing and/or alleviating severe pain due to intractable ischemia for patients with CLI. To simulate the blood circulation of related anatomy, in vitro CLI model phantom was designed and constructed by using a modified hemodialysis circuit, a hemodialysis pump and a tube set for cardio-pulmonary bypass surgery. A blood mimicking fluid (BMF) with dynamic viscosity of 4.1 mPa.s was used at 22 ºC to prime the phantom. The data was collected by a custom-made circuit design in real time and all measurements were verified with commercial certificated medical devices. The results of in vitro CLI model phantom experiments have shown that it is feasible to elevate the pressure distal to the occlusion (representing ankle pressure) above 80 mmHg without affecting the systemic pressure.

Piezo1 (Piezo-Type Mechanosensitive Ion Channel Component 1)-Mediated Mechanosensation in Macrophages Impairs Perfusion Recovery After Hindlimb Ischemia in Mice

BACKGROUND

Angiogenesis is a promising strategy for those with peripheral artery disease. Macrophage-centered inflammation is intended to govern the deficiency of the angiogenic response after hindlimb ischemia. However, little is known about the mechanism of macrophage activation beyond signals from cytokines and chemokines. We sought to identify a novel mechanical signal from the ischemic microenvironment that provokes macrophages and the subsequent inflammatory cascade and to investigate the potential role of Piezo-type mechanosensitive ion channels (Piezo) on macrophages during this process.

METHODS

Myeloid cell-specific Piezo1 (Piezo-type mechanosensitive ion channel component 1) knockout (Piezo1^ΔMΦ) mice were generated by crossing Piezo1^fl/fl (LysM-Cre^-/-; Piezo1 flox/flox) mice with LysM-Cre transgenic mice to assess the roles of Piezo1 in macrophages after hindlimb ischemia. Furthermore, in vitro studies were carried out in bone marrow-derived macrophages to decipher the underlying mechanism.

RESULTS

We found that tissue stiffness gradually increased after hindlimb ischemia, as indicated by Young's modulus. Compared to Piezo2, Piezo1 expression and activation were markedly upregulated in macrophages from ischemic tissues in concurrence with increased tissue stiffness. Piezo1^ΔMΦ mice exhibited improved perfusion recovery by enhancing angiogenesis. Matrigel tube formation assays revealed that Piezo1 deletion promoted angiogenesis by enhancing FGF2 (fibroblast growth factor-2) paracrine signaling in macrophages. Conversely, activation of Piezo1 by increased stiffness or the agonist Yoda1 led to reduced FGF2 production in bone marrow-derived macrophages, which could be blocked by Piezo1 silencing. Mechanistically, Piezo1 mediated extracellular Ca²⁺ influx and activated Ca²⁺-dependent CaMKII (calcium/calmodulin-dependent protein kinase II)/ETS1 (ETS proto-oncogene 1) signaling, leading to transcriptional inactivation of FGF2.

CONCLUSIONS

This study uncovers a crucial role of microenvironmental stiffness in exacerbating the macrophage-dependent deficient angiogenic response. Deletion of macrophage Piezo1 promotes perfusion recovery after hindlimb ischemia through CaMKII/ETS1-mediated transcriptional activation of FGF2. This provides a promising therapeutic strategy to enhance angiogenesis in ischemic diseases.

Mesenchymal stem cells in ischemic tissue regeneration

Diseases caused by ischemia are one of the leading causes of death in the world. Current therapies for treating acute myocardial infarction, ischemic stroke, and critical limb ischemia do not complete recovery. Regenerative therapies opens new therapeutic strategy in the treatment of ischemic disorders. Mesenchymal stem cells (MSCs) are the most promising option in the field of cell-based therapies, due to their secretory and immunomodulatory abilities, that contribute to ease inflammation and promote the regeneration of damaged tissues. This review presents the current knowledge of the mechanisms of action of MSCs and their therapeutic effects in the treatment of ischemic diseases, described on the basis of data from in vitro experiments and preclinical animal studies, and also summarize the effects of using these cells in clinical trial settings. Since the obtained therapeutic benefits are not always satisfactory, approaches aimed at enhancing the effect of MSCs in regenerative therapies are presented at the end.

Development of a Fuzzy Diagnostic Model of Ischemic Disease of the Lower Limbs for Different Stages of Patient Management

Ischemic disease has severe impact on patients which makes accurate diagnosis vital for health protection. Improving the quality of prediction of patients with ischemic extremity disease by using hybrid fuzzy model allows for early and accurate prognosis of the development of the disease at various stages. The prediction of critical ischemia of lower extremity (CLI) at various disease stages is complex problem due to inter-related factors. We developed hybrid fuzzy decision rules to classify ischemic severity using clinical thinking (natural intelligence) with artificial intelligence, which allows achieving a new quality in solving complex systemic problems and is innovative. In this study mathematical model was developed to classify the risk level of CLI into: subcritical ischemia, favorable outcome, questionable outcome, and unfavorable outcome. The prognosis is made using such complex indicators as confidence that the patient will develop gangrene of the lower extremity (unfavorable outcome), complex coefficient of variability, and reversibility of the ischemic process. Model accuracy was calculated using representative control samples that showed high diagnostic accuracy and specificity characterizing the quality of prediction are 0.9 and higher, which makes it possible to recommend their use in medical practice.

Polytetrafluorethylene (PTFE) vs. Polyester (Dacron®) Grafts in Critical Limb Ischemia Salvage

BACKGROUND

Critical ischemia of the lower limbs refers to the last stages of peripheral arterial disease. It is characterized by resting discomfort or trophic disorders such as ulceration, skin necrosis, or gangrene in the lower limbs. Critical ischemia corresponds to Leriche-Fontaine (LF) stages III-IV and Rutherford stages 4-6. The purpose of this study was to observe the patency and postoperative complications of patients who have had infra-inguinal surgical revascularization and compare the results based on the kind of graft utilized.

METHODS

The present study was designed as an observational retrospective cohort study, including all patients from 2018 to 2019 diagnosed with severe ischemia of the lower limbs who were hospitalized at the Vascular Surgery Clinic of the County Emergency Clinical Hospital of Targu Mures.

RESULTS

Patients with a polytetrafluoroethylene (PTFE) graft had a higher incidence of chronic obstructive pulmonary disease (p = 0.01), stage III LF (70.41% vs. 55.29%), p = 0.03), and a lower incidence of stage IV LF (29.95% vs. 44.71%, p = 0.03). As for complications, the PTFE group showed a lower incidence of bypass thrombosis (29.59% vs. 44.71%; p = 0.03) and graft infection (9.18% vs. 21.18%; p = 0.02), but no statistical significance in the event of bleeding (p = 0.40). Regarding the outcomes, no statistical significance was seen for below-the-knee amputations or death. However, the PTFE group had a lower incidence of above-the-knee amputations (11.22% vs. 24.71%; p = 0.01). At multivariate analysis, the PTFE graft is an independent predictor of primary patency at 6, 12, and 24 months (OR: 2.15, p = 0.02; OR: 1.84, p = 0.04; and OR: 1.89, p = 0.03), as well as a protective factor against bypass thrombosis (OR: 0.52; p = 0.03), graft infection (OR: 0.37; p = 0.02), and above-the-knee amputation (OR: 0.38; p = 0.01).; Conclusions: According to this study's findings, there were minor differences regarding the long-term patency, bypass thrombosis, graft infections, and above-the-knee amputations. In addition, the PTFE graft group had a higher incidence of primary patency at 6, 12, and 24 months, as well as a lower incidence of bypass thrombosis, graft infection, and above-the-knee amputations.

[Hybrid interventions for atherosclerotic lesions of the lower limb arteries]

Treatment of multilevel atherosclerotic lesions of the lower limb arteries is an acute problem in modern medicine. There is no a single treatment algorithm. Hybrid technologies are one of the possible treatment options. There are reasonable assumptions that these technologies can at least partially solve this problem. Minor trauma is an undoubted advantage of hybrid technologies. Therefore, these approaches are advisable in severe patients with various comorbidities and contraindications for traditional methods. Therefore, analysis of hybrid methods is of great interest for cardiovascular surgeons. Hybrid method is now recognized as one of the most effective and minimally traumatic treatment for patients with atherosclerotic lesions of the lower extremities.

Nanoceria-GO-intercalated multicellular spheroids revascularize and salvage critical ischemic limbs through anti-apoptotic and pro-angiogenic functions

Critical limb ischemia (CLI) is a serious form of peripheral arterial disease that involves severe blockage of blood flow in lower extremities, often leading to foot necrosis and limb loss. Lack of blood flow and high pro-inflammation with overproduced reactive oxygen species (ROS) in CLI aggravate the degenerative events. Among other therapies, cell delivery is considered potential for restoring regenerative capacity, and preservation of cell survival under high oxidative stress has been challenging and prerequisite to harness cellular functions. Here, we introduce a multicellular delivery system that is intercalated with nanoceria-decorated graphene oxide (CeGO), which is considered to have high ROS scavenging ability while providing cell-matrix interaction signals. The CeGO nano-microsheets (8-nm-nanoceria/0.9-μm-GO) incorporated in HUVEC/MSC (7/3) could form cell-material hybrid spheroids mediated by cellular contraction. Under in vitro oxidative-stress-challenge with H₂O₂, the CeGO-intercalation enhanced the survival and anti-apoptotic capacity of cellular spheroids. Pro-angiogenic events of cellular spheroids, including cell sprouting and expression of angiogenic markers (HIF1α, VEGF, FGF2, eNOS) were significantly enhanced by the CeGO-intercalation. Proteomics analysis also confirmed substantial up-regulation of a series of angiogenesis-related secretome molecules. Such pro-angiogenic events with CeGO-intercalation were proven to be mediated by the APE/Ref-1 signaling pathway. When delivered to ischemic hindlimb in mice, the CeGO-cell spheroids could inhibit the accumulation of in vivo ROS rapidly, preserving high cell survival rate (cells were more proliferative and less apoptotic vs. those in cell-only spheroids), and up-regulated angiogenic molecular expressions. Monitoring over 28 days revealed significantly enhanced blood reperfusion and tissue recovery, and an ultimate limb salvage with the CeGO-cell delivery (∼60% salvaged vs. ∼29% in cell-only delivery vs. 0% in ischemia control). Together, the CeGO intercalated in HUVEC/MSC delivery is considered a potential nano-microplatform for CLI treatment, by scavenging excessive ROS and enhancing transplanted cell survival, while stimulating angiogenic events, which collectively help revascularization and tissue recovery, salvaging critical ischemic limbs.

Prosthetic vascular graft management in above-knee amputations

OBJECTIVE

Critical limb ischaemia (CLI) is the most severe state of peripheral arterial disease and is one of the major causes of lower-limb amputations. One of the treatment choices is prosthetic vascular grafts. Despite treatment, CLI may lead to amputation owing to infection or progressive ischaemia. The aim of this study was to show that multidisciplinary planning and surgery for CLI patients with prosthetic grafts decreased the duration of hospital stay, costs, risk of infection and ascending conversion of the amputation level.

METHODS

Forty-two above-knee amputation patients with grafts were retrospectively evaluated. Group A patients (n = 24) had partial excision and group B patients ( n = 18) total excision with or without saphenous patch-plasty, according to the patency of the deep femoral artery. Growth in wound culture, antibiotic therapy duration, conversion to hip disarticulation and hospitalisation periods were compared.

RESULTS

Differences in growth of wound culture (p = 0.007), antibiotic duration (p = 0.003), hip disarticulation (p = 0.029) and duration of hospital stay (p = 0.0001) between the two groups were found to be statistically significant (p < 0.05).

CONCLUSIONS

Management of CLI patients is a complex process, and a multidisciplinary approach is key to avoiding undesirable outcomes. Meticulous planning, including excision of the total graft, while ensuring the vascular supply, is essential.

Upgrading Monocytes Therapy for Critical Limb Ischemia Patient Treatment: Pre-Clinical and GMP-Validation Aspects

Advanced cell therapy medicinal products (ATMP) are at the forefront of a new range of biopharmaceuticals. The use of ATMP has evolved and increased in the last decades, representing a new approach to treating diseases that are not effectively managed with conventional treatments. The standard worldwide recognized for drug production is the Good Manufacturing Practices (GMP), widely used in the pharma production of synthesized drugs but applying also to ATMP. GMP guidelines are worldwide recognized standards to manufacture medicinal products to guarantee high quality, safety, and efficacy. In this report, we describe the pre-clinical and the GMP upgrade of peripheral blood mononuclear cell (PBMC) preparation, starting from peripheral blood and ending up with a GMP-grade clinical product ready to be used in patients with critical limb ischemia (CLI). We also evaluated production in hypoxic conditions to increase PBMC functional activity and angiogenic potential. Furthermore, we extensively analyzed the storage and transport conditions of the final product as required by the regulatory body for ATMPs. Altogether, results suggest that the whole manufacturing process can be performed for clinical application. Peripheral blood collected by a physician should be transported at room temperature, and PBMCs should be isolated in a clean room within 8 h of venipuncture. Frozen cells can be stored in nitrogen vapors and thawed for up to 12 months. PBMCs resuspended in 5% human albumin solution should be stored and transported at 4 °C before injection in patients within 24 h to thawing. Hypoxic conditioning of PBMCs should be implemented for clinical application, as it showed a significant enhancement of PBMC functional activity, in particular with increased adhesion, migration, and oxidative stress resistance. We demonstrated the feasibility and the quality of a GMP-enriched suspension of monocytes as an ATMP, tested in a clean room facility for all aspects related to production in respect of all the GMP criteria that allow its use as an ATMP. We think that these results could ease the way to the clinical application of ATMPs.

The relationship between sarcopenia and one-year mortality in patients with critical limb ischemia undergoing endovascular therapy below the knee

OBJECTIVE

Critical limb ischemia (CLI) is a progressive form of peripheral artery disease (PAD). Patients with CLI have poor long-term prognosis. The aim of this study was to investigate the value of sarcopenia in terms of 1-year mortality in patients with below-the-knee lesions who underwent endovascular treatment for CLI.

METHODS

A total of 190 patients with critical limb ischemia who underwent endovascular treatment (EVT) for below-the-knee (BTK) lesions were enrolled in this study. Sarcopenia was defined using the psoas muscle index (PMI). PMI was obtained by calculating the average psoas muscle area (APMA) of the left and right psoas muscles at the third lumbar vertebra level and dividing by the square of the height (cm²/m²). The primary endpoint of the study was 1-year mortality and the secondary endpoint was 1-year amputation. Patients were divided into 2 groups according to presence of sarcopenia.

RESULTS

We detected sarcopenia in 64 patients. The mean age, height, and EF were higher in sarcopenia group. The psoas muscle area, weight, psoas muscle index, body-mass index, albumin level, and GFR were lower in sarcopenia group. The incidence of amputation (11.9% vs 29.7%, p = 0.003) and mortality (15.1% vs 35.9%, p = 0.001) were higher in patients with sarcopenia. Univariate and multivariate logistic regression analyses were used to determine the independent predictors of amputation and mortality. The survival curve for 1-year using the sarcopenia was analyzed using the Kaplan-Meier method, and statistical analysis was performed with the log-rank test. The presence of sarcopenia, glomerular filtration rate level, and low ejection fraction were found to be independent predictors of mortality.

CONCLUSIONS

Sarcopenia was associated with 1-year mortality in patients with CLI undergoing EVT for BTK lesions. Also, patients with sacropenia had higher 1-year amputation rates. Sarcopenia may be a simple method to help patient selection, assessment, and intervention strategy for EVT and may improve patient outcomes.

Mid-Term Outcomes of Endovascular Therapy for TASC II D Femoropopliteal Lesions with Critical Limb Ischaemia: A Retrospective Analysis

OBJECTIVE

This study evaluated the mid-term results of endovascular therapy (EVT) for Trans-Atlantic Inter-Society (TASC) II D femoropopliteal lesions in patients with critical limb ischaemia (CLI).

METHODS

Fifty-seven limbs of 54 patients with CLI due to TASC II D femoropopliteal lesions who underwent EVT at the First Hospital of Hebei Medical University were retrospectively analysed in single-centre, observational study. The patient characteristics, endovascular procedural details, freedom from target lesion revascularisation (TLR), patency rates, ulcer healing rate, and limb salvage rate were accessed.

RESULTS

The patients' mean age was 68.2 ± 8.2 years. All patients were treated by EVT. The final technical success rate was 98.2% (56/57). There were 23 cases of pain at rest, 18 cases of ulcer, and 15 cases of gangrene. The median length of the treated segment was 286 ± 42 mm (56/56) and the mean number of stents placed per patient was 2.0 ± 0.8 (49/56). The postoperative ankle-brachial index (ABI) was significantly higher than that of the preoperative ABI (P < 0.05). The perioperative complication rate was 10.7% (6/56). The re-stenosis or occlusion rate was 44.6% (25/56). The estimated rates of freedom from TLR at 1 year, 2 years, and 3 years were 86.8%, 67.0%, and 62.5%, respectively. Univariate analysis showed that predictors of freedom from TLR were the number of runoff vessels, length of the lesion, and complexity of the lesion, while predictors for re-stenosis or occlusion were the length and the complexity of the lesion. The ulcer healing rate was 93.8%. The limb salvage rates were 76.4%, 74.4%, and 70.9% at 1, 2, and 3 years after treatment, respectively.

CONCLUSIONS

The mid-term outcomes of EVT for TASC II D femoropopliteal lesions in patients with CLI indicated that this treatment approach is safe and effective, and is clinically applicable.

Revascularization Techniques for Limb Salvage in Critical Limb Ischemia: A Single Institutional Study From Pakistan

Objectives: The study aimed to determine the frequency of successful limb salvage in patients presenting with critical limb ischemia utilizing the available revascularization modalities. This descriptive cross-sectional study was conducted in the Department of General Surgery, Shifa International Hospital, Islamabad, from April 2017 to August 2017.

Methodology: A total of 96 patients with critical limb ischemia requiring urgent surgery for limb salvage were included in our study. Patients who had undergone previous surgeries for limb ischemia involving the same limb, had concurrent venous disease, or suffered from acute limb ischemia were excluded. All patients underwent either endoscopic angioplasty or bypass surgery. All patients were followed up for six months for the success of limb salvage and the requirement for amputation. Data were analyzed by SPSS version 26.0 (Armonk, NY: IBM Corp.).

Results: Our patients had a mean age of 62.03±8.46 years, of whom 63 (65.6%) were men. A total of 47 (49.0%) patients required surgery for a non-healing ulcer, while 49 (51.0%) had resting leg pain. In 55 (57.3%) patients, bypass surgery was performed, while 35 (36.5%) underwent endoscopic angioplasty. The remaining six (6.2%) patients received a combination of both procedures. Limb salvage was successful in 78 (81.3%) patients. There was no difference between outcomes across gender (p=0.122), nor was there any difference in outcome between bypass surgery and endoscopic angioplasty (p=0.665).

Conclusion: Encouraging results can be obtained in treatment of critical limb ischemia if revascularization techniques are utilized prudently in a time-effective manner and individualized to each patient's requirements.

Endovascular Treatment and Outcomes for Femoropopliteal In-Stent Restenosis: Insights from the XLPAD Registry

Background

There is limited “real-world” evidence examining treatment modalities and outcomes in patients with symptomatic peripheral arterial disease undergoing endovascular treatment of femoropopliteal (FP) in-stent restenosis (ISR).

Materials and Methods

We compared outcomes in 2,895 patients from the XLPAD registry (NCT01904851) between 2006 and 2019 treated for FP ISR (n = 347) and non-ISR (n = 2,548) lesions. Primary endpoint included major adverse limb events (MALE) at 1 year, a composite of all-cause death, target limb repeat revascularization, or major amputation.

Results

ISR patients were more frequently on antiplatelet (94.5% vs 89.4%, p=0.007) and statin (68.9% vs 60.3%, p=0.003) therapies. Lesion length was similar (ISR: 145 ± 99 mm vs. non-ISR: 142 ± 99 mm, p=0.55). Fewer treated ISR lesions were chronic total occlusions (47.3% vs. 53.7%, p=0.02) and severely calcified (22.4% vs. 44.7%, p < 0.001). Atherectomy (63.5% vs. 45.0%, p < 0.001) and drug-coated balloons (DCB; 4.7% vs. 1.7%, p < 0.001) were more frequently used in ISR lesions. The distal embolization rate was higher in ISR lesions (2.4% vs. 0.9%, p=0.02). Repeat revascularization (21.5% vs. 16.7%, p=0.04; Figure) was higher and freedom from MALE at 1 year was significantly lower (87% vs. 92.5%, p < 0.001) in the ISR group.

Conclusion

Atherectomy and DCB are more frequently used to treat FP ISR lesions. Patients with FP ISR have more intraprocedural distal embolization, higher repeat revascularization procedures, and lower freedom from MALE at 1 year.

Risk Factors for Major Adverse Cardiovascular Events and Major Adverse Limb Events after Venous Thromboembolism: A Large Prospective Cohort Study

BACKGROUND

 There is an increased risk of arterial events including major adverse cardiovascular events (MACE) and major adverse limb events (MALE) after venous thromboembolism (VTE). However, their risk factors remain little explored.

METHODS

 We aimed to determine the risk factors for MACE (acute coronary syndrome/stroke/cardiovascular death) and MALE (limb ischemia/critical limb ischemia/non-traumatic amputation/any limb revascularization) after VTE. Competing risk models (Fine-Gray) were used in a multicenter prospective cohort of 4,940 patients (mean age: 64.6 years and median follow-up: 64 months).

RESULTS

 MACE occurred in 17.3% of participants (2.35% per patient-years) and MALE in 1.7% (0.27% per patient-years). In multivariable analysis, the identified risk factors for MACE were the age of 50 to 65 years (vs. <50 years, hazard ratio [HR]: 2.00, 95% confidence interval [CI]: 1.38-2.91), age >65 years (vs. <50 years, HR 4.85, 95% CI: 3.35-7.02), pulmonary embolism + deep vein thrombosis (DVT) (vs. isolated-DVT, HR: 1.25, 95% CI: 1.02-1.55), unprovoked-VTE (vs. transient risk factor associated-VTE, HR: 1.29, 95% CI: 1.04-1.59), current tobacco use (vs. never, HR: 1.45, 95% CI: 1.07-1.98), hypertension (HR: 1.61, 95% CI: 1.30-1.98), past history of symptomatic atherosclerosis (HR: 1.52, 95% CI: 1.17-1.98), heart failure (HR: 1.71, 95% CI: 1.21-2.42), atrial fibrillation (HR: 1.55, 95% CI: 1.15-2.08), and vena cava filter insertion (HR: 1.46, 95% CI: 1.03-2.08). The identified risk factors for MALE were the age of 50-65 years (vs. <50 years, HR: 3.49, 95% CI: 1.26-9.65) and atrial fibrillation (HR: 2.37, 95% CI: 1.15-4.89).

CONCLUSIONS

 Risk factors for MACE and MALE after VTE included some traditional cardiovascular risk factors, patient's comorbidities, and some characteristics of VTE.

Development of an ischemic fracture healing model in mice

BACKGROUND AND PURPOSE

In fracture healing, ischemia caused by vascular injuries, chronic vascular diseases, and metabolic comorbidities is one of the major risk factors for delayed union and non-union formation. To gain novel insights into the molecular and cellular pathology of ischemic fracture healing, appropriate animal models are needed. Murine models are of particular interest, as they allow to study the molecular aspects of fracture healing due to the availability of both a large number of murine antibodies and gene-targeted animals. Thus, we present the development of an ischemic fracture healing model in mice.

MATERIAL AND METHODS

After inducing a mild ischemia by double ligature of the deep femoral artery in CD-1 mice, the ipsilateral femur was fractured by a 3-point bending device and stabilized by screw osteosynthesis. In control animals, the femur was fractured and stabilized without the induction of ischemia. The femora were analyzed at 2 and 5 weeks after fracture healing by means of radiology, biomechanics, histology, and histomorphometry.

RESULTS

The surgically induced ischemia delayed and impaired the process of fracture healing. This was indicated by a lower Goldberg score, decreased bending stiffness, and reduced bone callus formation in the ischemic animals when compared with the controls.

INTERPRETATION

We introduce a novel ischemic femoral fracture healing model in mice, which is characterized by delayed bone healing. In future, the use of this model may allow both the elucidation of the molecular aspects of ischemic fracture healing and the study of novel treatment strategies.

Tibial cortex transverse transport accelerates wound healing via enhanced angiogenesis and immunomodulation

AIMS

Treatment for delayed wound healing resulting from peripheral vascular diseases and diabetic foot ulcers remains a challenge. A novel surgical technique named 'tibial cortex transverse transport' (TTT) has been developed for treating peripheral ischaemia, with encouraging clinical effects. However, its underlying mechanisms remain unclear. In the present study, we explored the potential biological mechanisms of TTT surgery using various techniques in a rat TTT animal model.

METHODS

A novel rat model of TTT was established with a designed external fixator, and effects on wound healing were investigated. Laser speckle perfusion imaging, vessel perfusion, histology, and immunohistochemistry were used to evaluate the wound healing processes.

RESULTS

Gross and histological examinations showed that TTT technique accelerated wound closure and enhanced the quality of the newly formed skin tissues. In the TTT group, haematoxylin and eosin (H&E) staining demonstrated a better epidermis and dermis recovery, while immunohistochemical staining showed that TTT technique promoted local collagen deposition. The TTT technique also benefited to angiogenesis and immunomodulation. In the TTT group, blood flow in the wound area was higher than that of other groups according to laser speckle imaging with more blood vessels observed. Enhanced neovascularization was seen in the TTT group with double immune-labelling of CD31 and α-Smooth Muscle Actin (α-SMA). The number of M2 macrophages at the wound site in the TTT group was also increased.

CONCLUSION

The TTT technique accelerated wound healing through enhanced angiogenesis and immunomodulation. Cite this article: Bone Joint Res 2022;11(4):189-199.

Twenty-Four Month Results of Tack-Optimized Balloon Angioplasty Using the Tack Endovascular System in Below-the-Knee Arteries

PURPOSE

To report 24 month safety and efficacy of the Tack Endovascular System for treatment of post-percutaneous transluminal angioplasty (PTA) infrapopliteal dissections in patients with critical limb-threatening ischemia (CLTI).

MATERIALS AND METHODS

The Tack-Optimized Balloon Angioplasty (TOBA) II below-the-knee (BTK) study was a prospective, multicenter, single-arm evaluation of the Tack Endovascular system for post-PTA infrapopliteal dissection repair. Patients with Rutherford Clinical Category (RC) 3 to 5 and a post-PTA dissection(s) of the BTK arteries were enrolled. The 30 day primary safety endpoint was a composite of major adverse limb events (MALE) and all-cause perioperative death (POD). The primary effectiveness endpoint was a composite of MALE at 6 months and 30 day POD. Outcomes were assessed as observational endpoints at 24 months.

RESULTS

Tack-Optimized Balloon Angioplasty II BTK enrolled 233 patients; all patients had a post-PTA dissection(s) and received ≥1 Tack implant (range, 1-16). Mean age was 74.4±10.0 years and 67.4% were men. Most patients had CLTI (RC 3: 16.3%; RC 4/5: 83.7%). Mean target lesion length was 80±49 mm. Moderate to severe calcium was present in 89 (35.8%) lesions and total occlusions were present in 118 (47.6%) lesions. Kaplan-Meier freedom from MALE at 24 months + POD at 30 days was 92.2% and 24 month freedom from clinically-driven target lesions revascularization was 73.6%. Kaplan-Meier target limb salvage was 95.7% and amputation-free survival was 75.4%. Improvements in functional status and quality of life were observed through 24 months.

CONCLUSION

The TOBA II BTK study demonstrated sustained safety and efficacy through 24 months in patients treated for post-PTA dissection(s) of BTK lesions.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02942966.

A method of characterising the complex anatomy of vascular occlusions and 3D printing biomimetic analogues

Chronic total occlusions (CTOs) occur in approximately 40% of individuals with symptomatic peripheral arterial disease and are indicative of critical limb ischaemia. Currently, few medical devices can effectively treat CTOs long-term, with amputation often required. This is due to a lack of knowledge of CTO anatomy, making device design and testing difficult. This study is a proof-of-concept study, which aimed to develop a workflow for further characterising the complex multi-material anatomy of CTOs and creating 3D models of CTO components, which may be useful in producing a vascular CTO biomimetic for device testing. Here, we establish such a workflow using samples of atheromatous plaques. We focus on a high-resolution, non-destructive microcomputed tomography (μCT) technique which enables visualisation of occlusion anatomy at a greater resolution than computed tomography angiography (CTA), which is the typical modality used for CTO clinical visualisation. Four arteries (n = 2 superficial femoral; n = 2 popliteal) with evidence of atheromatous plaques were cut into 8 cm segments, which were then stained with iodine and scanned at low resolution, with calcified regions rescanned at high resolution. Resulting files were manually segmented to generate 3D models, which were then 3D printed in resin using a stereolithography printer to produce parts suitable for creating a biomimetic. In total, μCT files from three arterial segments (n = 2 high resolution, n = 1 low resolution) were deemed suitably calcified for segmentation, and thus were segmented to produce 3D models. 3D models of the arterial wall, intima and atheromatous calcium deposits from a high-resolution popliteal artery scan were successfully 3D printed at several scales. While this research is at an early stage, it holds great promise. The workflow for segmentation and 3D printing various components of an atheromatous plaque established here is replicable and uses software and equipment which are accessible to research laboratories in both academia and industry. The ability to print detailed models on a desktop 3D printer is unprecedented and can be improved further, which is promising for future development of biomimetics with multi-material detail of both soft tissue and calcified components of a vascular occlusion. Indeed, this workflow provides a solid foundation for future studies of CTO anatomy and the creation of true, multi-material CTO biomimetics. Such biomimetics may enable the development of improved interventional devices, as they would mimic the general in vivo CTO environment. As this method cannot be applied in vivo, we cannot yet produce patient-specific biomimetics, however, these analogues would still be important in device development, which would improve patient outcomes in critical limb ischaemia.

E-Selectin-Overexpressing Mesenchymal Stem Cell Therapy Confers Improved Reperfusion, Repair, and Regeneration in a Murine Critical Limb Ischemia Model

AIMS

Novel cell-based therapeutic angiogenic treatments for patients with critical limb ischemia may afford limb salvage. Mesenchymal stem cells (MSCs) do not overexpress E-selectin; however, we have previously demonstrated the cell-adhesion molecule's vital role in angiogenesis and wound healing. Thus, we created a viral vector to overexpress E-selectin on MSCs to increase their therapeutic profile.

METHODS AND RESULTS

Femoral artery ligation induced hind limb ischemia in mice and intramuscular injections were administered of vehicle or syngeneic donor MSCs, transduced ex vivo with an adeno-associated viral vector to express either GFP+ (MSCGFP) or E-selectin-GFP+ (MSCE-selectin-GFP). Laser Doppler Imaging demonstrated significantly restored reperfusion in MSCE-selectin-GFP-treated mice vs. controls. After 3 weeks, the ischemic limbs in mice treated with MSCE-selectin-GFP had increased footpad blood vessel density, hematoxylin and eosin stain (H&E) ischemic calf muscle sections revealed mitigated muscular atrophy with restored muscle fiber size, and mice were able to run further before exhaustion. PCR array-based gene profiling analysis identified nine upregulated pro-angiogenic/pro-repair genes and downregulated Tumor necrosis factor (TNF) gene in MSCE-selectin-GFP-treated limb tissues, indicating that the therapeutic effect is likely achieved via upregulation of pro-angiogenic cytokines and downregulation of inflammation.

CONCLUSION

This innovative cell therapy confers increased limb reperfusion, neovascularization, improved functional recovery, decreased muscle atrophy, and thus offers a potential therapeutic method for future clinical studies.

Role of Doppler Ultrasound and Percutaneous Transluminal Angioplasty in Early Diagnosis and Management of Peripheral Artery Disease

BACKGROUND: Peripheral arterial disease (PAD) denotes vascular disorder which peripheral artery’s obstruction or constriction is found. PAD with diabetic history is more susceptible to ischemic ulcer than PAD with no diabetic. The presence of Diabetes mellitus (DM) in PAD can speed up 4 times greater risk of developing Critical Limb Ischemia. In our hospital, difficulty performing extremity perfusion assessment is often found because those examinations are not available, so possibility of PAD can be missed. Therefore, optimalization use of Doppler Ultrasound (DUS) is important in our case. AIM: The purpose of our case writing is to give information about substantial parameter of DUS in determine presence of PAD and define the role of percutaneous transluminal angioplasty (PTA) in PAD. The earlier PAD discovered, faster further treatment conducted, especially PTA. CASE REPORT: A 65-year-old female patient with intermittent left calf pain for 7 months who went to internal medicine outpatient has reported. She has history of type 2 DM and significant hyperlipidemia. On physical examination, vital signs revealed normal value. Body mass index was 28 kg/m2. Resting ankle-brachial index (ABI) measurement was 1.14 and 1.12 at the right and left dorsalis pedis, respectively. DUS showed spectral narrow, reversal flow and no clear spectral window in superficial femoral artery. There are clear spectral window, spectral narrow, and reversal flow in poplitea artery. No clear spectral window, no spectral narrow, and no reversal flow in anterior tibia artery. Clear spectral window, reversal flow, and no spectral narrow are appear in posterior tibia artery. Arteriogram of left inferior extremity showed middle part partial stenosis of anterior tibia artery. Dilatation with standard balloon for 1 min was done. After that, no stenosis in same location and she wasn’t feel calf pain again. CONCLUSION: Compared with two other parameters, reversal flow in DUS is most important parameter to establish presence of stenosis. PTA is adequate to give revascularization stenosis in PAD.

Dynamic Multiscale Regulation of Perfusion Recovery in Experimental Peripheral Arterial Disease: A Mechanistic Computational Model

•

A first-of-a-kind systems biology computational model is presented that describes multiscale regulation of perfusion recovery in experimental peripheral arterial disease.

•

Multilevel model calibration and validation enable high-resolution model simulations for experimental peripheral arterial disease (mouse HLI).

•

An integrative model-based mechanistic characterization of the intracellular, cellular, and tissue-level features critical for the dynamic reconstitution of perfusion following different patterns of occlusion-induced ischemia in HLI is described.

•

Using a model-based virtual HLI mouse population, pharmacologic inhibition of cell necrosis is predicted as a strategy with high therapeutic potential to improve perfusion recovery; in real HLI mice, the positive impact of this new strategy is then experimentally studied and confirmed.

In peripheral arterial disease (PAD), the degree of endogenous capacity to modulate revascularization of limb muscle is central to the management of leg ischemia. To characterize the multiscale and multicellular nature of revascularization in PAD, we have developed the first computational systems biology model that mechanistically incorporates intracellular, cellular, and tissue-level features critical for the dynamic reconstitution of perfusion after occlusion-induced ischemia. The computational model was specifically formulated for a preclinical animal model of PAD (mouse hindlimb ischemia [HLI]), and it has gone through multilevel model calibration and validation against a comprehensive set of experimental data so that it accurately captures the complex cellular signaling, cell–cell communication, and function during post-HLI perfusion recovery. As an example, our model simulations generated a highly detailed description of the time-dependent spectrum-like macrophage phenotypes in HLI, and through model sensitivity analysis we identified key cellular processes with potential therapeutic significance in the pathophysiology of PAD. Furthermore, we computationally evaluated the in vivo effects of different targeted interventions on post-HLI tissue perfusion recovery in a model-based, data-driven, virtual mouse population and experimentally confirmed the therapeutic effect of a novel model-predicted intervention in real HLI mice. This novel multiscale model opens up a new avenue to use integrative systems biology modeling to facilitate translational research in PAD.

The role of directional atherectomy in critical-limb ischemia

Background:

Our aim was to review the current literature of the use of directional atherectomy (DA) in the treatment of lower extremity critical-limb ischemia.

Methods:

A search for relevant literature was performed in PubMed and PubMed Central on 16 April 2020, sorted by best match. Three searches across two databases were performed. Articles were included that contained clinical and procedural data of DA interventions in lower extremity critical-limb ischemia patients. All studies that were systematic reviews were excluded.

Results:

Eleven papers were included in this review. Papers were examined under several parameters: primary patency and secondary patency, limb salvage/amputation, technical/procedural success, complications/periprocedural events, and mean lesion length. Primary and secondary patency rates ranged from 56.3% to 95.0% and 76.4% to 100%, respectively. Limb salvage rates ranged from 69% to 100%. Lesion lengths were highly varied, representing a broad population, ranging from 30 ± 33 mm to 142.4 ± 107.9 mm.

Conclusions:

DA may be a useful tool in the treatment of lower extremity critical-limb ischemia.

Case Report: Diabetic nephropathy aggravates the progression and prognosis of COVID-19-associated acute limb ischemia

Hypercoagulation is a hallmark of both the novel coronavirus disease (COVID-19) and type 2 diabetes mellitus (T2DM). It increases the risk for vascular thrombosis, including peripheral artery diseases. Among others, acute limb ischemia (ALI) is one of most common complications that requires immediate and prompt treatments to reduce morbidity and mortality. However, the complex interplay between COVID-19, T2DM and its complications (e.g., diabetic nephropathy), and ALI creates a great challenge in the management of the disease. Here, we present a case of a 59-year-old diabetic female with progressive pain in her left leg in the last five years, which was significantly intensified following COVID-19 diagnosis. Bluish coloration, numbness and functional impairments were observed during examinations with no palpable pulsation on left posterior tibial and dorsalis pedis arteries. The patient also had diabetic nephropathy (stage III), hypoalbuminemia, anemia and a urinary tract infection that complicated the management of the disease. Due to the excruciating pain and the worsening of the limb conditions, right leg revascularization and left leg amputation were performed at day 14 after admission. Following the surgeries, no more pain was observed and patient was discharged for further follow-up at the outpatient clinic.

Antithrombotic Therapy in Peripheral Artery Disease: Stepping in the Right Direction

We reviewed the various antithrombotic therapies available to treat peripheral artery disease (PAD). A literature review using the PubMed and MEDLINE databases used the following keywords: antithrombotic therapy, anticoagulation, peripheral artery disease, and peripheral vascular disease. Randomized studies written in English that assessed the use of antithrombotic therapy in patients with PAD were evaluated. PAD is a worldwide condition that limits blood flow in the lower extremities, leading to a risk of major adverse cardiovascular events and major adverse limb events. Antithrombotic therapy is necessary to prevent these complications, and the choice of therapy depends upon the stage of disease progression. For symptomatic patients in the beginning stage, single antiplatelet therapy (SAPT) is the preferred therapy, specifically, aspirin. For patients undergoing endovascular revascularization, the preferred therapy is dual antiplatelet therapy using aspirin and clopidogrel combined for at least the first month followed by long-term SAPT. For patients undergoing surgical revascularization, the preferred choice of therapy depends upon the type of graft used, with better results obtained with antiplatelet therapy for prosthetic grafts and anticoagulation for venous grafts. New studies have shown that therapy using both antiplatelets and anticoagulation in the form of aspirin plus low-dose rivaroxaban can reduce complications in all three patient populations, which has paved the way for future studies featuring direct oral anticoagulants with the potential to change current guideline recommendations.

Improving Symptoms of Peripheral Artery Disease With Hirudotherapy

Peripheral artery disease (PAD) is a significant cause of morbidity and mortality in the world. Critical limb ischemia is a complication of PAD that leads to severe pain at rest, numbness, and absent or diminished pulses in the legs or feet. Revascularization with surgery or endovascular intervention is required to re-establish blood flow to the affected areas. Failure to respond to medical and/or surgical treatment can lead to amputations. The decision to amputate one’s limb can be very challenging. Here, we report a patient with critical limb ischemia who refused a below-the-knee amputation and self-treated with medicinal leech therapy, or hirudotherapy. His symptoms including his pain, burning, and numbness improved significantly following six months of therapy.

Simultaneous Hybrid Treatment of Multilevel Peripheral Arterial Disease in Patients with Chronic Limb-Threatening Ischemia

Background: Hybrid treatments (HT) aim to reduce conventional open surgery invasiveness and address multilevel peripheral arterial disease (PAD). Herein, the simultaneous HT treatment in patients with chronic limb-threatening ischemia (CLTI) is reported. Methods: Retrospective analysis, for the period from May 2012 to April 2018, of patients presenting multilevel PAD with CLTI addressed with simultaneous HT. The outcomes of these interventions were measured the following metrics: early technical successes (within 30 days following treatment) and late technical successes (30 days or more following treatment) and included mortality, morbidity symptoms recurrence, and amputation. Survival and patencies were estimated. The median follow-up was 43.77 months. Results: In the 45 included patients, the HT consisted of femoral bifurcation patch angioplasty followed by an endovascular treatment in 38 patients (84.4%) and endovascular treatment followed by a surgical bypass in 7 patients (15.6%). Technical success was 100% without perioperative mortality. Eight (17.8%) patients presented early complications without major amputations. During the follow-up, seven (15.6%) deaths occurred and six patients (13.3%) experienced symptoms recurrence, with five of those patients requiring major amputation. An estimated survival time of 5 years, primary patency, and secondary patency was 84.4%, 79.2%, and 83.3% respectively. Conclusions: Hybrid treatments are effective in addressing patients presenting with multilevel PAD and CLTI. The common femoral artery involvement influences strategy selection. Larger studies with longer-term outcomes are required to validate the hybrid approach, indications, and results.

Important Role of Concomitant Lymphangiogenesis for Reparative Angiogenesis in Hindlimb Ischemia

[Figure: see text].

Neutrophil-to-lymphocyte ratio associated with an increased risk of mortality in patients with critical limb ischemia

Purpose

Association of the neutrophil-to-lymphocyte ratio (NLR) with mortality has not been comprehensively explored in critical limb ischemia (CLI) patients. We investigated the association between the NLR and clinical outcomes in CLI.

Materials and methods

We retrospectively enrolled consecutive CLI patients between 1/1/2013 and 12/31/2018. Receiver operating characteristic curve analysis determined NLR cutoffs for 1-year in-hospital, all-cause and cardiac-related mortality; major adverse cardiovascular events (MACEs); and major adverse limb events (MALEs).

Results

Among 195 patients (age, 74.0 years, SD: 11.5; 51.8% male; body mass index, 23.4 kg/m², SD: 4.2), 14.4% exhibited acute limb ischemia. After 1 year, patients with NLR>8 had higher in-hospital mortality (21.1% vs. 3.6%, P<0.001), all-cause mortality (54.4% vs. 13.8%, P<0.001), cardiac-related mortality (28.1% vs. 6.5%, P<0.001), MACE (29.8% vs. 13.0%, P = 0.008), and MALE (28.1% vs. 13.0%, P = 0.021) rates than those with NLR<8. In multivariate logistic regression, NLR≥8 was significantly associated with all-cause (P<0.001) and cardiac-related (adjusted HR: 5.286, 95% CI: 2.075–13.47, P<0.001) mortality, and NLR≥6 was significantly associated with MALEs (adjusted HR: 2.804, 95% CI: 1.292–6.088, P = 0.009). Each increase in the NLR was associated with increases in all-cause (adjusted HR: 1.028, 95% CI: 1.008–1.049, P = 0.007) and cardiac-related (adjusted HR:1.027, 95% CI: 0.998–1.057, P = 0.073) mortality but not in-hospital mortality or MACEs.

Conclusion

CLI patients with high NLRs had significantly higher risks of 1-year all-cause and cardiac-related mortality and MALEs. The NLR can be used for prognostic prediction in these patients.