Inflammation and Loss of Skeletal Muscle Mass in Chronic Limb Threatening Ischemia.

BACKGROUND: Lower extremity peripheral arterial disease (PAD) is an atherosclerotic disease of the lower extremities. Atherosclerosis, inflammation, and sarcopenia are independently associated and potentiate each other. Inflammation is deeply involved in the formation and progression of atherosclerosis and is also involved in the pathophysiology of sarcopenia. Sarcopenia is defined as low muscle mass, with low muscle strength. This study aims to determine the differences in skeletal muscle characteristics and in inflammatory parameters between patients with claudication and with chronic limb threatening ischemia (CLTI). METHODS: An observational, prospective study in patients with PAD was conducted from January 2018 to December 2020. The clinical characteristics and the cardiovascular risk factors were prospectively registered. The inflammatory parameters determined were: positive acute phase proteins (C-reactive Protein- CRP- and fibrinogen) and negative acute phase proteins albumin, total cholesterol and high-density lipoprotein (HDL). The skeletal muscle area and density were quantified with a computed topography (CT) scan. The strength was determined with a Jamar® hydraulic hand dynamometer. RESULTS: A total of 116 patients (mean age: 67.65 ± 9.53 years-old) 64% with claudication and 46% with CLTI were enrolled in the study. No differences were registered between patients with claudication and CLTI on age, cardiovascular risk factors (hypertension, dyslipidemia, diabetes mellitus, and smoking habits) and medication. There was a higher prevalence of men in the claudication group (88.89% vs. 71.70%, P = 0.019). Analyzing the inflammatory parameters, we noted that patients with CLTI had increased serum levels of positive acute phase proteins: CRP (37.53 ± 46.61 mg/L vs. 9.18 ± 26.12 mg/L, P = 0.000), and fibrinogen (466.18 ± 208.07 mg/dL vs. 317.37 ± 79.42 mg/dL, P = 0.000). CLTI patients had decreased negative acute phase proteins: albumin (3.53 ± 0.85 g/dL vs. 3.91 ± 0.72 g/dL, P = 0.001), total cholesterol (145.41 ± 38.59 mg/dL vs. 161.84 ± 34.94 mg/dL, P = 0.013) and HDL (38.70 ± 12.19 mg/dL vs. 51.31 ± 15.85 mg/dL, P = 0.000). We noted that patients with CLTI had lower skeletal muscle area and mass (14,349.77 ± 3,036.60 mm2 vs. 15,690.56 ± 3,183.97 mm2P = 0.013; 10.11 ± 17.03HU vs. 18.02 ± 13.63HU P = 0.013). After adjusting for the variable sex, the association between skeletal muscle density and CLTI persisted (r (97) = -0.232, P = 0.021). The groups did not differ in strength (patients with claudication: 25.39 ± 8.23 Kgf vs. CLTI: 25.17 ± 11.95 Kgf P = 0.910). CONCLUSIONS: CLTI patients have decreased skeletal muscle mass and a systemic inflammation status. Recognizing the deleterious triad of atherosclerosis, inflammation and loss of skeletal mass patients with CLTI is an opportunity to improve medical therapy and to perform a timely intervention to stop this vicious cycle.

Interventional- and amputation-stage muscle proteomes in the chronically threatened ischemic limb.

BACKGROUND: Despite improved surgical approaches for chronic limb-threatening ischemia (CLTI), amputation rates remain high and contributing tissue-level factors remain unknown. The purpose of this study was twofold: (1) to identify differences between the healthy adult and CLTI limb muscle proteome, and (2) to identify differences in the limb muscle proteome of CLTI patients prior to surgical intervention or at the time of amputation. METHODS AND RESULTS: Gastrocnemius muscle was collected from non-ischemic controls (n = 19) and either pre-interventional surgery (n = 10) or at amputation outcome (n = 29) CLTI patients. All samples were subjected to isobaric tandem-mass-tag-assisted proteomics. The mitochondrion was the primary classification of downregulated proteins (> 70%) in CLTI limb muscles and paralleled robust functional mitochondrial impairment. Upregulated proteins (> 38%) were largely from the extracellular matrix. Across the two independent sites, 39 proteins were downregulated and 12 upregulated uniformly. Pre-interventional CLTI muscles revealed a robust upregulation of mitochondrial proteins but modest functional impairments in fatty acid oxidation as compared with controls. Comparison of pre-intervention and amputation CLTI limb muscles revealed mitochondrial proteome and functional deficits similar to that between amputation and non-ischemic controls. Interestingly, these observed changes occurred despite 62% of the amputation CLTI patients having undergone a prior surgical intervention. CONCLUSIONS: The CLTI proteome supports failing mitochondria as a phenotype that is unique to amputation outcomes. The signature of pre-intervention CLTI muscle reveals stable mitochondrial protein abundance that is insufficient to uniformly prevent functional impairments. Taken together, these findings support the need for future longitudinal investigations aimed to determine whether mitochondrial failure is causally involved in amputation outcomes from CLTI.

Contemporary outcomes of concomitant suprainguinal bypass with infrainguinal revascularization procedures in patients with chronic limb-threatening ischemia.

OBJECTIVE: Combined suprainguinal and infrainguinal revascularization is sometimes necessary in the treatment of patients with chronic limb-threatening ischemia (CLTI). However, data on outcomes of concomitant revascularization procedures are lacking. We studied the outcomes of patients with CLTI who underwent suprainguinal bypass (SIB) alone, SIB with concomitant infrainguinal bypass (IIB), and SIB with concomitant infrainguinal peripheral endovascular intervention (IIPVI). METHODS: We reviewed all patients in the Vascular Quality Initiative with CLTI who underwent SIB from January 2010 to June 2020. Logistic regression, Kaplan-Meier survival estimates, log-rank tests, and Cox regression were used to analyze outcomes. Outcomes were 30-day mortality, perioperative myocardial infarction, perioperative major amputation, 1-year amputation-free survival, and 5-year survival. RESULTS: Of 8037 patients included, 81.3% (n = 6537) underwent SIB alone, 9.7% (n = 783) underwent SIB+IIB, and 8.9% (n = 717) underwent SIB+IIPVI. The indication for surgery was rest pain in 5040 (62.5%) and tissue loss in 3031 (37.6%). There were no significant differences in 30-day mortality and perioperative myocardial infarction rates. However, there was 2.8-fold increased odds of perioperative major amputation in both SIB+IIPVI (odds ratio [OR], 2.76; 95% confidence interval [CI], 1.30-5.88; P = .008) and SIB+IIB (OR, 2.79; 95% CI, 1.38-5.54; P = .004) among patients with rest pain as compared with SIB alone. Comparing SIB+IIPVI with SIB alone, there were no significant differences in 1-year freedom from amputation and amputation-free survival. SIB+IIPVI was associated with a 27% increased risk of 5-year mortality (hazard ratio [HR], 1.27; 95% CI, 1.03-1.55; P = .035). Compared with SIB alone, SIB+IIB was associated with 97% increased risk of 1-year major amputation among patients with rest pain (HR, 1.97; 95% CI, 1.06-3.69; P = .033), but a 47% decreased risk of 1-year major amputation or death for patients with tissue loss (HR, 0.53; 95% CI, 0.37-0.78; P = .001). SIB+IIPVI, compared with SIB+IIB, was associated with a two-fold increased risk of 1-year major amputation or death (HR, 2.04; 95% CI, 1.04-2.23), P = .003) and a 52% increased risk of 5-year mortality (HR,1.52; 95% CI, 1.04-2.24; P = .032) among patients with tissue loss. CONCLUSIONS: This study shows that SIB with concomitant infrainguinal revascularization in patients with rest pain is associated with an increased risk of amputation, whereas SIB+IIB in patients with tissue loss is associated with decreased risk of amputation or death. SIB+IIB outperformed SIB+IIPVI in patients with tissue loss. SIB with infrainguinal revascularization should be limited in patients with rest pain in line with current guidelines, but SIB+IIB may be preferred in patients with tissue loss.

A single center's 15-year experience with palliative limb care for chronic limb threatening ischemia in frail patients.

OBJECTIVE: Our institution's multidisciplinary Prevention of Amputation in Veterans Everywhere (PAVE) program allocates veterans with critical limb threatening ischemia (CLTI) to immediate revascularization, conservative care, primary amputation, or palliative limb care according to previously reported criteria. These four groups align with the approaches outlined by the global guidelines for the management of CLTI. In the present study, we have delineated the natural history of the palliative limb care group of patients and quantified the procedural risks and outcomes. METHODS: Veterans prospectively enrolled into the palliative limb cohort of our PAVE program from January 2005 to January 2020 were analyzed. The primary outcome was mortality. The secondary outcomes included overall and limb-related readmissions, limb loss, and wound healing. The clinical frailty scale (CFS) score was calculated, and the 5-year expected mortality was estimated using the Veterans Affairs Quality Enhancement Research Initiative tool. Regression analysis was performed to establish associations among the following variables: mortality, wound, ischemia, and foot infection (WIfI) score, CFS score, overall admissions, and limb-related admissions. RESULTS: The PAVE program enrolled 1158 limbs during 15 years. Of the 1158 limbs, 157 (13.5%) in 145 patients were allocated to the palliative limb care group. The overall mortality of the group was 88.2% (median interval, 3.5 months; range, 0-91 months). Of the 128 patients who had died, 64 (50%) had died within 3 months of enrollment. The predicted 5-year mortality for the group was 66%. The average CFS score for the group was 6.2, denoting persons moderately to severely frail. Using the CFS score, 106 patients were considered frail and 39 were considered not frail. No differences were found in mortality between the frail and nonfrail patients. However, a statistically significant difference was found in early (<3 months) mortality (56.2% vs 37.5%; P = .032). The 30-day limb-related readmission rate was 4.7%. Eventual major amputation was necessary for 18 limbs (11.5%). Wound healing occurred in 30 patients (20.6%). Regression analysis demonstrated no association between the CFS score and mortality (r = 0.55; P = .159) or between the WIfI score and mortality (r = 0.0165; P = .98). However, a significant association was found between the WIfI score and limb-related admissions (r = 0.97; P < .001). CONCLUSIONS: Frail patients with CLTI had high early mortality and a low risk of limb-related complications. They also had a low incidence of deferred primary amputation or limb-related readmissions. In our cohort, the vast majority of patients had died within a few months of enrollment without requiring an amputation. A comprehensive approach to the treatment of CLTI patients should include a palliative limb care option because a significant proportion of these patients will have limited survival and can potentially avoid unnecessary surgery and major amputation.

Isquemia arterial aguda de membros superiores em pacientes diagnosticados com COVID-19: série de casos / Acute upper limb arterial ischemia in patients diagnosed with COVID-19: case series

Resumo A infecção pelo coronavírus 2 causador da síndrome respiratória aguda grave (SARS-CoV-2) em humanos foi detectada pela primeira vez em Wuhan, na China, em 2019 e dispersada mundialmente ao longo de 2020. As diferentes manifestações clínicas, com amplo espectro de apresentação, desde infecções assintomáticas até formas graves que podem levar a óbito, são desafiadoras. Este trabalho objetiva descrever uma série de quatro casos de isquemia arterial aguda dos membros superiores em pacientes diagnosticados com COVID-19, os quais foram manejados clinicamente com anticoagulação, antiagregação plaquetária e uso de prostanoides. Dois pacientes receberam alta hospitalar com regressão e delimitação da área isquêmica, sem necessidade de intervenção cirúrgica, e dois pacientes faleceram em decorrência de complicações pulmonares. Uma adequada compreensão da fisiopatologia dessa doença pode favorecer um melhor manejo clínico de suas complicações.

Abstract Infection by coronavirus 2, cause of the severe acute respiratory syndrome (SARS-CoV-2) in humans, was detected for the first time in Wuhan, China, in 2019, and spread globally over the course of 2020. Its different clinical manifestations are challenging, with a wide spectrum of presentations, ranging from asymptomatic infections to severe forms that can result in death. The objective of this study is to describe a series of four cases of acute arterial ischemia involving the upper limbs in patients diagnosed with COVID-19, which were managed clinically with anticoagulation, platelet antiaggregation, and prostanoids. Two patients were discharged from hospital with regression and delimitation of the ischemic zone, without needing surgical intervention, while two patients died from pulmonary complications. Adequate understanding of the pathophysiology of this disease could support better clinical management of its complications.

Estudo comparativo experimental da distribuição do fluxo arterial, em isquemia e reperfusão por circulação retrógrada, através de mapeamento dúplex / Experimental, comparative, duplex mapping study of arterial flow distribution in ischemia and reperfusion by retrograde circulation

Resumo A isquemia crítica de membro inferior sem leito distal tem opções restritas para tratamento. Desviar o fluxo sanguíneo de maneira retrógrada através da circulação venosa é uma alternativa amparada em evidências de inúmeros trabalhos publicados. Comparou-se através de mapeamento dúplex a distribuição do fluxo sanguíneo arterial em membros posteriores de suínos mantidos em circulação fisiológica com o contralateral submetido à isquemia e reperfusão por circulação retrógrada. O fluxo nos membros em circulação fisiológica e retrógrada foi avaliado por mapeamento dúplex através da determinação da velocidade de pico sistólico (VPS), da velocidade diastólica final (VDF) e do índice de resistividade (IR) em artérias selecionadas. A análise comparativa das extremidades mantidas em circulação fisiológica em relação às mantidas em isquemia e reperfusão, por circulação retrógrada, mostrou nestas, ao mapeamento dúplex, que as alterações nos padrões de onda espectral e nas variáveis hemodinâmicas são indicadores satisfatórios e sugerem boa distribuição do fluxo sanguíneo vascular distal.

Abstract Treatment options for critical lower limb ischemia in the absence of the distal bed are limited. Diverting blood flow in a retrograde direction through the venous circulation is one alternative option that is supported by evidence from several published articles. Duplex scanning was used to compare the distribution of arterial flow in hind limbs of pigs maintained in physiological circulation to contralateral limbs subjected to ischemia and reperfusion by retrograde circulation. Flow in limbs with physiological and retrograde circulation was evaluated by duplex scanning with analysis of Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV), and the Resistivity Index (RI) for selected arteries. This comparative analysis of extremities maintained in physiological circulation in relation to those subjected to ischemia and reperfusion by retrograde circulation showed, via duplex scanning, that changes in spectral wave patterns and hemodynamic variables are satisfactory indicators and suggest good distribution of distal blood flow.