Cortical Reorganization after Limb Loss: Bridging the Gap between Basic Science and Clinical Recovery.

Despite the increasing incidence and prevalence of amputation across the globe, individuals with acquired limb loss continue to struggle with functional recovery and chronic pain. A more complete understanding of the motor and sensory remodeling of the peripheral and central nervous system that occurs postamputation may help advance clinical interventions to improve the quality of life for individuals with acquired limb loss. The purpose of this article is to first provide background clinical context on individuals with acquired limb loss and then to provide a comprehensive review of the known motor and sensory neural adaptations from both animal models and human clinical trials. Finally, the article bridges the gap between basic science researchers and clinicians that treat individuals with limb loss by explaining how current clinical treatments may restore function and modulate phantom limb pain using the underlying neural adaptations described above. This review should encourage the further development of novel treatments with known neurological targets to improve the recovery of individuals postamputation.Significance Statement In the United States, 1.6 million people live with limb loss; this number is expected to more than double by 2050. Improved surgical procedures enhance recovery, and new prosthetics and neural interfaces can replace missing limbs with those that communicate bidirectionally with the brain. These advances have been fairly successful, but still most patients experience persistent problems like phantom limb pain, and others discontinue prostheses instead of learning to use them daily. These problematic patient outcomes may be due in part to the lack of consensus among basic and clinical researchers regarding the plasticity mechanisms that occur in the brain after amputation injuries. Here we review results from clinical and animal model studies to bridge this clinical-basic science gap.

Illness Trajectories After Revascularization in Patients With Peripheral Artery Disease: A Unified Approach to Understanding the Risk of Major Amputation and Death.

BACKGROUND: The aim of this study was to investigate the illness trajectories of patients with peripheral artery disease (PAD) after revascularization and estimate the independent risks of major amputation and death (from any cause) and their interaction. METHODS: Data from Hospital Episode Statistics Admitted Patient Care were used to identify patients (≥50 years of age) who underwent lower limb revascularization for PAD in England from April 2013 to March 2020. A Markov illness-death model was developed to describe patterns of survival after the initial lower limb revascularization, if and when patients experienced major amputation, and survival after amputation. The model was also used to investigate the association between patient characteristics and these illness trajectories. We also analyzed the relative contribution of deaths after amputation to overall mortality and how the risk of mortality after amputation was related to the time from the index revascularization to amputation. RESULTS: The study analyzed 94 690 patients undergoing lower limb revascularization for PAD from 2013 to 2020. The majority were men (65.6%), and the median age was 72 years (interquartile range, 64-79). One-third (34.8%) of patients had nonelective revascularization, whereas others had elective procedures. For nonelective patients, the amputation rate was 15.2% (95% CI, 14.4-16.0) and 19.9% (19.0-20.8) at 1 and 5 years after revascularization, respectively. For elective patients, the corresponding amputation rate was 2.7% (95% CI, 2.4-3.1) and 5.3% (4.9-5.8). Overall, the risk of major amputation was higher among patients who were younger, had tissue loss, diabetes, greater frailty, nonelective revascularization, and more distal procedures. The mortality rate at 5 years after revascularization was 64.3% (95% CI, 63.2-65.5) for nonelective patients and 33.0% (32.0-34.1) for elective patients. After major amputation, patients were at an increased risk of mortality if they underwent major amputation within 6 months after the index revascularization. CONCLUSIONS: The illness-death model provides an integrated framework to understand patient outcomes after lower limb revascularization for PAD. Although mortality increased with age, the study highlights patients <60 years of age were at increased risk of major amputation, particularly after nonelective revascularization.

Current Status and Principles for the Treatment and Prevention of Diabetic Foot Ulcers in the Cardiovascular Patient Population: A Scientific Statement From the American Heart Association.

Despite the known higher risk of cardiovascular disease in individuals with type 2 diabetes, the pathophysiology and optimal management of diabetic foot ulcers (DFUs), a leading complication associated with diabetes, is complex and continues to evolve. Complications of type 2 diabetes, such as DFUs, are a major cause of morbidity and mortality and the leading cause of major lower extremity amputation in the United States. There has recently been a strong focus on the prevention and early treatment of DFUs, leading to the development of multidisciplinary diabetic wound and amputation prevention clinics across the country. Mounting evidence has shown that, despite these efforts, amputations associated with DFUs continue to increase. Furthermore, due to increasing patient complexity of management secondary to comorbid conditions, such as cardiovascular disease, the management of peripheral artery disease associated with DFUs has become increasingly difficult, and care delivery is often episodic and fragmented. Although structured, process-specific approaches exist at individual institutions for the management of DFUs in the cardiovascular patient population, there is insufficient awareness of these principles in the general medicine communities. Furthermore, there is growing interest in better understanding the mechanistic underpinnings of DFUs to better define personalized medicine to improve outcomes. The goals of this scientific statement are to provide salient background information on the complex pathogenesis and current management of DFUs in cardiovascular patients, to guide therapeutic and preventive strategies and future research directions, and to inform public policy makers on health disparities and other barriers to improving and advancing care in this expanding patient population.

Rivaroxaban Plus Aspirin Versus Aspirin Alone After Endovascular Revascularization for Symptomatic PAD: Insights From VOYAGER PAD.

BACKGROUND: Rivaroxaban plus aspirin compared with aspirin alone reduced major cardiac and ischemic limb events after lower extremity revascularization (LER) in the VOYAGER PAD (Vascular Outcomes Study of ASA Along With Rivaroxaban in Endovascular or Surgical Limb Revascularization for Peripheral Artery Disease) trial. The effect has not been described in patients undergoing endovascular LER. METHODS: The VOYAGER PAD trial randomized 6564 patients with symptomatic peripheral artery disease to a double-blinded treatment with 2.5 mg of rivaroxaban BID or matching placebo and 100 mg of aspirin daily. The primary efficacy outcome was a composite of acute limb ischemia, major amputation of a vascular pathogenesis, myocardial infarction, ischemic stroke, or cardiovascular death. The principal safety end point was Thrombolysis in Myocardial Infarction major bleeding. A prespecified subgroup of patients who underwent endovascular revascularization was included. RESULTS: Endovascular LER occurred in 4379 (66.7%) patients and surgical LER in 2185 (33.3%). Over a 3-year follow-up, rivaroxaban reduced the risk of the primary outcome by 15% (hazard ratio [HR], 0.85 [95% CI, 0.76-0.96]) with an absolute risk reduction of 0.92% at 6 months and 1.04% at 3 years and a consistent benefit in those receiving endovascular (HR, 0.89 [95% CI, 0.76-1.03]) or surgical LER (HR, 0.81 [95% CI, 0.67-0.98]; P interaction=0.43). For endovascular-treated patients, rivaroxaban reduced the risk of acute limb ischemia or major amputation of a vascular pathogenesis by 30% (HR, 0.70 [95% CI, 0.54-0.90]; P=0.005) with an absolute risk reduction of 1.0% at 6 months and 2.0% at 3 years compared with aspirin alone. Among endovascular-treated patients, the median duration of concomitant dual antiplatelet therapy with clopidogrel treatment was 31 days (interquartile range, 30-58). There was a consistent benefit for rivaroxaban regardless of background clopidogrel. Thrombolysis in Myocardial Infarction major bleeding was significantly higher for the rivaroxaban and aspirin group for the endovascular cohort (HR, 1.66 [95% CI, 1.06-2.59]) with an absolute risk increase of 0.9% at 3 years with no increase in intracranial or fatal bleeding observed (HR, 0.86 [95% CI, 0.40-1.87]; P=0.71). Mortality with rivaroxaban was higher in the endovascular-treated patients (HR, 1.24 [95% CI, 1.02-1.52]), although this finding was isolated to specific regions. CONCLUSIONS: Rivaroxaban added to aspirin or dual antiplatelet therapy after LER for peripheral artery disease reduces ischemic risk and increases major bleeding without an increased risk of intracranial or fatal bleeding. These benefits are consistent in those treated with endovascular and surgical approaches with significant benefits for major adverse limb events. These data support the use of rivaroxaban in addition to aspirin or dual antiplatelet therapy after endovascular intervention for symptomatic peripheral artery disease.

Fenofibrate to prevent amputation and reduce vascular complications in patients with diabetes: FENO-PREVENT.

BACKGROUND: The potential preventive effect of fenofibrate on lower extremity amputation (LEA) and peripheral arterial disease (PAD) in patients with type 2 diabetes (T2D) is not fully elucidated. METHODS: We selected adult patients ≥ 20 years of age with T2D from the Korean National Health Insurance Service Database (2009-2012). The fenofibrate users were matched in a 1:4 ratio with non-users using propensity scores (PS). The outcome variables were a composite of LEA and PAD and the individual components. The risks of outcomes were implemented as hazard ratio (HR) with 95% confidence intervals (CI). For safety issues, the risks of acute kidney injury, rhabdomyolysis and resulting hospitalization were analyzed. RESULTS: A total of 114,920 patients was included in the analysis with a median follow-up duration of 7.6 years (22,984 and 91,936 patients for the fenofibrate user and non-user groups, respectively). After PS matching, both groups were well balanced. The fenofibrate group was associated with significantly lower risks of composite outcome of LEA and PAD (HR 0.81; 95% CI 0.70-0.94), LEA (HR 0.76; 95% CI 0.60-0.96), and PAD (HR 0.81; 95% CI 0.68-0.96). The risk of acute kidney injury, rhabdomyolysis, or hospitalization for these events showed no significant difference between the two groups. Subgroup analyses revealed consistent benefits across age groups, genders, and baseline lipid profiles. CONCLUSIONS: This nationwide population-based retrospective observational study suggests that fenofibrate can prevent LEA and PAD in patients with T2D who are on statin therapy.

Diabetic foot disease carries an intrinsic high risk of mortality and other severe outcomes in type 2 diabetes: a propensity score-matched retrospective population-based study.

BACKGROUND: To evaluate the association between diabetic foot disease (DFD) and the incidence of fatal and non-fatal events in individuals with type 2 diabetes (T2DM) from primary-care settings. METHODS: We built a cohort of people with a first DFD episode during 2010-2015, followed up until 2018. These subjects were 1 to 1 propensity score matched to subjects with T2DM without DFD. The incidence of all-cause mortality, the occurrence of new DFD, amputations, cardiovascular diseases, or composite outcome, including all-cause mortality and/or cardiovascular events during the follow-up period, were calculated. A Cox proportional hazard analysis was conducted to evaluate the hazard ratios (HR) for different events. RESULTS: Overall, 11,117 subjects with T2DM with a first episode of DFD were compared with subjects without DFD. We observed higher incidence rates (IRs) for composite outcome (33.9 vs. 14.5 IR per 100 person-years) and a new DFD episode event (22.2 vs. 1.1 IR per 100 person-years) in the DFD group. Compared to those without DFD, those with a first episode of DFD had a higher HR for all events, with excess rates particularly for amputation and new DFD occurrence (HR: 19.4, 95% CI: 16.7-22.6, HR: 15.1, 95% CI: 13.8-16.5, respectively) was found. CONCLUSIONS: Although DFD often coexists with other risk factors, it carries an intrinsic high risk of morbidity and mortality in individuals with T2DM. DFD should be regarded as a severe complication already at its onset, as it carries a poor clinical prognosis.

Independent association of history of diabetic foot with all-cause mortality in patients with type 2 diabetes: the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study.

BACKGROUND: Foot ulcers and/or infections are common long-term complications of diabetes and are associated with increased mortality, especially from cardiovascular disease, though only a few studies have investigated the independent contribution of these events to risk of death. This study aimed at assessing the association of history of diabetic foot with all-cause mortality in individuals with type 2 diabetes, independent of cardiovascular risk factors, other complications, and comorbidities. METHODS: This prospective cohort study enrolled 15,773 Caucasian patients in 19 Italian centers in the years 2006-2008. Prior lower extremity, coronary, and cerebrovascular events and major comorbidities were ascertained by medical records, diabetic retinopathy by fundoscopy, diabetic kidney disease by albuminuria and estimated glomerular filtration rate, cardiovascular risk factors by standard methods. All-cause mortality was retrieved for 15,656 patients on 31 October 2015. RESULTS: At baseline, 892 patients (5.7%) had a history of diabetic foot, including ulcer/gangrene and/or amputation (n = 565; 3.58%), with (n = 126; 0.80%) or without (n = 439; 2.78%) lower limb revascularization, and revascularization alone (n = 330; 2.09%). History of diabetic foot was associated with all-cause death over a 7.42-year follow-up (adjusted hazard ratio, 1.502 [95% confidence interval, 1.346-1.676], p < 0.0001), independent of confounders, among which age, male sex, smoking, hemoglobin A1c, current treatments, other complications, comorbidities and, inversely, physical activity level and total and HDL cholesterol were correlated independently with mortality. Both ulcer/gangrene and amputation alone were independently associated with death, with a higher strength of association for amputation than for ulcer/gangrene (1.874 [1.144-3.070], p = 0.013 vs. 1.567 [1.353-1.814], p < 0.0001). Both ulcer/gangrene/amputation and lower limb revascularization alone were independently associated with death; mortality risk was much higher for ulcer/gangrene/amputation than for revascularization (1.641 [1.420-1.895], p < 0.0001 vs. 1.229 [1.024-1.475], p = 0.018) and further increased only slightly for combined ulcer/gangrene/amputation and revascularization (1.733 [1.368-2.196], p < 0.0001). CONCLUSIONS: In patients with type 2 diabetes, an history of diabetic foot event, including ulcer/gangrene, amputation, and lower limb revascularization, was associated with a ~ 50% increased risk of subsequent death, independent of cardiovascular risk factors, other complications and severe comorbidities, which were also significantly associated with mortality. The association with mortality was greatest for amputation, whereas that for revascularization alone was relatively modest. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00715481, retrospectively registered 15 July, 2008.

Prosthetic outcomes after amputation and the impact of mobility level on survival.

OBJECTIVE: Lower extremity amputation continues to be necessary in a significant number of patients with peripheral vascular disease. The 5-year survival following lower limb loss is markedly reduced. Many of these patients are never fitted with a prosthesis, and there is a dearth of knowledge regarding the barriers to prosthetic attainment. The goal of this study was to identify the risk factors for not receiving a prosthesis and the effect of mobility level on survival following major amputation. METHODS: This was a retrospective analysis of all patients that underwent lower extremity amputation by surgeons in our practice from January 1, 2010, to December 31, 2019. Abstracted data included: age, sex, race, body mass index, comorbidities, American Society of Anesthesiologists score, statin use, level of amputation, stump revision, fitting for prosthesis, type of prosthesis, and the United States' Medicare Functional Classification Level, also called K level. Survival was determined using a combination of sources, including the Social Security Death Master File, searches of multiple genealogic registries, and general internet searches. Multivariable logistic regression was used to determine risk factors associated with prosthesis attainment. Multivariable Cox proportional hazard regression with time-dependent covariates was performed to assess risk factors associated with 5-year mortality. RESULTS: A total of 464 patients were included in this study. The mean age was 65 years, and mean body mass index was 27 kg/m2. The majority of patients were male (68%), White (56%), diabetic (62%), and hypertensive (76%), and underwent below-the-knee amputation (69%). Prosthetic attainment occurred in 185 (40%). On multivariable analysis, age >81 years and current tobacco use were associated with no prosthetic fitting. Overall 5-year survival was 41.9% (95% confidence interval [CI], 37.6%-46.6%) (below-the-knee amputation, 47.7% [95% CI, 42.5%-53.5%]; above-the-knee amputation, 28.7% [95% CI, 22.1%-37.2%]). On multivariable analysis, age >60 years, congestive heart failure, above-the-knee amputation, and no prosthetic attainment were associated with decreased survival. Increasing K level was incrementally associated with improved survival. CONCLUSIONS: This study has identified several patient factors associated with prosthetic attainment, as well as multiple factors predictive of reduced survival after amputation. Being referred for prosthetic fitting was associated with improved survival not explained by patient characteristics and comorbidities. The Medicare Functional Classification Level K level predicts survival. More research is needed to determine the barriers to prosthetic attainment and if improving a patients K level will improve survival.

Patients with dementia or frailty undergoing major limb amputation have poor outcomes.

OBJECTIVE: Major lower limb amputation is a disfiguring operation associated with impaired mobility and high near-term mortality. Informed decision-making regarding amputation requires outcomes data. Despite the co-occurrence of both chronic limb-threatening ischemia (CLTI) and Alzheimer's Disease and related dementias (ADRD), there is sparse data on the outcomes of major limb amputation in this population and the impact of frailty. We sought to determine mortality, complications, readmissions, revisions, intensive interventions (e.g., cardiopulmonary resuscitation), and other outcomes after amputation for CLTI in patients living with ADRD looking at the modifying effects of frailty. METHODS: We examined Medicare fee-for-service claims data from January 1, 2016 to December 31, 2020. Patients with CLTI undergoing amputation at or proximal to the ankle were included. Along with demographic information, dementia status, and comorbid conditions, we measured frailty using a claims-based frailty index. We dichotomized dementia and frailty (pre-frail/robust = "non-frail" vs moderate/severe frailty = "frail") to create four groups: non-frail/non-ADRD, frail/non-ADRD, non-frail/ADRD, and frail/ADRD. We used linear and logistic regression via generalized estimating equations in addition to performing selected outcomes analyses with death as a competing risk to understand the association between dementia status, frailty status, and one-year mortality as our primary outcome in addition to the postoperative outcomes outlined above. RESULTS: Among 46,930 patients undergoing major limb amputation, 11,465 (24.4%) had ADRD and 24,790 (52.8%) had frailty. Overall, 55.9% of amputations were below-knee. Selected outcomes among frail/ADRD patients undergoing amputation (N=10,153) were: 55.3% one-year mortality 29.6% readmissions at 30 days, and 32.3% amputation revision/reoperation within one year. Of all four groups, those in the frail/ADRD had the worst outcomes only for 1-year mortality. CONCLUSIONS: First, patients with ADRDw or moderate/severe frailty suffer an array of very poor outcomes after major limb amputation for CLTI including high mortality, readmissions, revision, and risks of discharge to higher levels of care. Second, there is a complex relationship between outcome severity and ADRD/frailty status. Specifically, frailty is more often than ADRD associated with the poorest results for any given outcome. These data provide important outcomes data to help align decision-making with healthcare values and goals.

Long-term outcomes in the smoking claudicant after peripheral vascular interventions.

OBJECTIVE: Emphasis on tobacco cessation, given the urgent and emergent nature of vascular surgery, is less prevalent than standard elective cases such as hernia repairs, cosmetic surgery, and bariatric procedures. The goal of this study is to determine the effect of active smoking on claudicating individuals undergoing peripheral vascular interventions (PVIs). Our goal is to determine if a greater emphasis on education should be placed on smoking cessation in nonurgent cases scheduled through clinic visits and not the Emergency Department. METHODS: This study was performed using the multi-institution de-identified Vascular Quality Initiative/Medicare-linked database (Vascular Implant Surveillance and Interventional Outcomes Network [VISION]). Claudicants who underwent PVI for peripheral arterial occlusive disease between 2004 and 2019 were included in our study. Our final sample consisted of a total of 18,726 patients: 3617 nonsmokers (19.3%) (NSs), 9975 former smokers (53.3%) (FSs), and 5134 current smokers (27.4%) (CSs). We performed propensity score matching on 29 variables (age, gender, race, ethnicity, treatment setting [outpatient or inpatient], obesity, insurance, hypertension, diabetes, coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, chronic kidney disease, previous coronary artery bypass graft, carotid endarterectomy, major amputation, inflow treatment, prior bypass or PVI, preoperative medications, level of treatment, concomitant endarterectomy, and treatment type [atherectomy, angioplasty, stent]) between NS vs FS and FS vs CS. Outcomes were long-term (5-year) overall survival (OS), limb salvage (LS), freedom from reintervention (FR), and amputation-free survival (AFS). RESULTS: Propensity score matching resulted in 3160 well-matched pairs of NS and FS and 3750 well-matched pairs of FS and CS. There was no difference between FS and NS in terms of OS (hazard ratio [HR], 0.94; 95% confidence interval [CI], 0.82-1.09; P = .43), FR (HR, 0.96; 95% CI, 0.89-1.04; P = .35), or AFS (HR, 0.90; 95% CI, 0.79-1.03; P = .12). However, when compared with CS, we found FS to have a higher OS (HR, 1.18; 95% CI, 1.04-1.33; P = .01), less FR (HR, 0.89; 95% CI, 0.83-0.96; P = .003), and greater AFS (HR, 1.16; 95% CI, 1.03-1.31; P = .01). CONCLUSIONS: This multi-institutional Medicare-linked study looking at elective PVI cases in patients with peripheral artery disease presenting with claudication found that FSs have similar 5-year outcomes in comparison to NSs in terms of OS, FR, and AFS. Additionally, CSs have lower OS and AFS when compared with FSs. Overall, this suggests that smoking claudicants should be highly encouraged and referred to structured smoking cessation programs or even required to stop smoking prior to elective PVI due to the perceived 5-year benefit.

Improved long-term functional outcomes and mortality of patients with vascular-related amputations utilizing the lower extremity amputation pathway.

BACKGROUND: Enhanced recovery after surgery pathways lead to improve perioperative outcomes for patients with vascular-related amputations; however, long-term data and functional outcomes are lacking. This study evaluated patients treated by the lower extremity amputation pathway (LEAP) and identified predictors of ambulation. METHODS: A retrospective review of LEAP patients who underwent major amputation from 2016 to 2022 for Wound, Ischemia, and foot Infection stage V disease was performed. LEAP patients were matched 1:1 with retrospective controls (NOLEAP) by hospital, need for guillotine amputation, and final amputation type (above knee vs below knee). The primary end point was the Medicare Functional Classification Level (K level) (functional classification of patients with amputations) at the last follow-up. RESULTS: We included 126 patients with vascular-related amputations (63 LEAP and 63 NOLEAP). Seventy-one percent of the patients were male and 49% were Hispanic with a mean state Area Deprivation Index of 9/10. There were no differences in baseline demographics or comorbidities. All patients had a K level of >0 (ambulatory) before amputation and an average Modified Frailty Index of 4. The median follow-up was 270 days (interquartile range, 84-1234 days) in the NOLEAP group and 369 days (interquartile range, 145-481 days) in the LEAP group. Compared with NOLEAP patients, LEAP patients were more likely to receive a prosthesis (86% vs 44%;P > .001). LEAP patients were more likely to have a K level of >0 (60% vs 25%; P = .003). On multivariable logistic regression, participation in LEAP increased the odds of a K level of >0 at follow-up by 5.8-fold (odds ratio, 5.8; 95% confidence interval, 2.5-13.6). Patients with a K level of >0 had significantly higher survival at 4 years (93% vs 59%; P = .001). In a Cox proportional hazards model, adjusted for demographics, comorbidities and amputation level, a K level of >0 at follow-up was associated with an 88% decrease in the risk of mortality compared with a K level of 0. CONCLUSIONS: LEAP leads to improved ambulation with a prosthesis in a socioeconomically disadvantaged and frail patient population. Patients with a K level of >0 (ambulatory) have significantly improved mortality.

Comparative evaluation of transcutaneous oxygen tension and ankle-brachial index as predictors of reoperation following below-knee amputation.

OBJECTIVE: Decision-making regarding level of lower extremity amputation is sometimes challenging. Selecting an appropriate anatomic level for major amputation requires consideration of tradeoffs between postoperative function and risk of wound complications that may require additional operations, including debridement and/or conversion to above-knee amputation (AKA). We evaluated the utility of common, non-invasive diagnostic tests used in clinical practice to predict the need for reoperations among patients undergoing primary, elective, below knee-amputations (BKAs) by vascular surgeons. METHODS: Patients undergoing elective BKA over a 5-year period were identified using Current Procedural Terminology codes. Medical records were reviewed to characterize demographics, pre-amputation testing transcutaneous oxygen tension (TcPO2), and ankle-brachial index (ABI). The need for ipsilateral post-BKA reoperation (including BKA revision and/or conversion to AKA) regardless of indication was the primary outcome. Associations were evaluated using univariable and multivariable logistic regression models. Cutpoints for TcPO2 values associated with amputation reoperation were evaluated using receiver operating characteristic curves. RESULTS: We identified 175 BKAs, of which 46 (26.3%) required ipsilateral reoperation (18.9% BKA revisions and 14.3% conversions to AKA). The mean age was 63.3 ± 14.8 years. Most patients were male (65.1%) and White (72.0%). Mean pre-amputation calf TcPO2 was 40.0 ± 20.5 mmHg, and mean ABI was 0.64 ± 0.45. In univariable models, post-BKA reoperation was associated with calf TcPO2 (odds ratio [OR], 0.97; 95% confidence interval [CI], 0.94-0.99; P = .013) but not ABI (OR, 0.53; 95% CI, 0.19-1.46; P = .217). Univariable associations with reoperation were also identified for age (OR, 0.97; 95% CI, 0.94-0.990; P = .003) and diabetes (OR, 0.43; 95% CI, 0.21-0.87; P = .019). No associations with amputation revision were identified for gender, race, end-stage renal disease, or preoperative antibiotics. Calf TcPO2 remained associated with post-BKA reoperation in a multivariable model (OR, 0.97; 95% CI, 0.94-0.99; P = .022) adjusted for age (OR, 0.98; 95% CI, 0.94-1.01; P = .222) and diabetes (OR, 0.98; 95% CI, 0.94-1.01; P = .559). Receiver operating characteristic analysis suggested a TcPO2 ≥38 mmHg as an appropriate cut-point for assessing risk for BKA revision (area under the curve = 0.682; negative predictive value, 0.91). CONCLUSIONS: Reoperation after BKA is common, and reoperation risk was associated with pre-amputation TcPO2. For patients undergoing elective BKA, higher risk of reoperation should be discussed with patients with an ipsilateral TcPO2 <38 mmHg.

A systematic review and meta-analysis on the influence of sociodemographic factors on amputation in patients with peripheral arterial disease.

OBJECTIVE: To identify disparities in sociodemographic factors that are associated with major lower limb amputation in patients with peripheral arterial disease (PAD). METHODS: A systematic review of the literature was performed to identify studies that reported major lower limb amputation rates in patients with PAD among different sociodemographic groups. Data that compared amputation rates on the basis of sex, race, ethnicity, income, insurance, geography, and hospital type were collected and described. Outcomes were then aggregated and standardized, and a meta-analysis was performed to synthesis data into single odds ratios (ORs). RESULTS: Forty-one studies were included in the review. There was no association found between males and females (OR, 0.95; 95% confidence interval [CI], 0.90-1.00). Compared with Whites, higher rates of amputation were seen among Blacks/African Americans (OR, 2.02; 95% CI, 1.81-2.26) and Native Americans (OR, 1.22; 95% CI, 1.04-1.45). No significant association was found between Whites and Asians, Native Hawaiians, or Pacific Islanders (OR, 1.15; 95% CI, 1.00-1.33). Hispanics had higher rates of amputation compared with non-Hispanics (OR, 1.36; 95% CI, 1.22-1.52). Compared with private insurance, higher rates of amputation were seen among Medicare patients (OR, 1.38; 95% CI, 1.27-1.50), Medicaid patients (OR, 1.59; 95% CI, 1.44-1.76), and noninsured patients (OR, 1.41; 95% CI, 1.02-1.95). Compared with the richest income quartile, higher rates of amputation were seen among the second income quartile (OR, 1.10; 95% CI, 1.05-1.15), third income quartile (OR, 1.20; 95% CI, 1.07-1.35), and bottom income quartile (OR, 1.36; 95% CI, 1.24-1.49). There was no association found between rural and urban populations (OR, 1.35; 95% CI, 0.92-1.97) or between teaching and nonteaching hospitals (OR, 1.01; 95% CI, 0.91-1.12). CONCLUSIONS: Our study has identified a number of disparities and quantified the influence of sociodemographic factors on major lower limb amputation rates owing to PAD between groups. We believe these findings can be used to better target interventions aimed at decreasing amputation rates, although further research is needed to better understand the mechanisms behind our findings.

Socioeconomic disadvantage is a leading variable in risk score for major amputation following emergent infrainguinal arterial bypass surgery.

OBJECTIVE: The purpose of this study was to identify patients at particularly high risk for major amputation after emergent infrainguinal bypass to help tailor postoperative and long-term patient management. METHODS: In the Vascular Quality Initiative, we identified 2126 patients who underwent emergent infrainguinal artery bypass. Two primary outcomes were investigated: major ipsilateral amputation above the ankle level during the index hospitalization and major amputation above the ankle at any time after emergent infrainguinal bypass surgery (perioperative and postdischarge combined). Binary logistic regression analysis was performed for each outcome using variables that achieved a univariable P value of ≤.10. We then determined which variables have a multivariable association for the outcomes as defined by a regression P value of ≤.05. A risk score was then created for the outcome of amputation after emergent infrainguinal bypass using weighted beta-coefficient. Variables with a multivariable P value of ≤.05 were included in the risk score and weighted based on their respective regression beta-coefficient in a point scale. RESULTS: Overall, 17.1% of patients (368/2126) underwent major amputation at some point in follow-up after emergent infrainguinal artery bypass. The mean follow-up duration on the amputation variable was 261 days with the end point being time of amputation or time of last follow-up data on the amputation variable. Variables with a significant multivariable association (P < .05) with major amputation at any point after emergent infrainguinal arterial bypass were home status in top 10% (most deprived) of Area Deprivation Index, prior infrainguinal ipsilateral arterial bypass, prior ipsilateral endovascular arterial intervention, prosthetic bypass conduit, postoperative skin/soft tissue infection, and postoperative need to revise or thrombectomize bypass. Pertinent negatives on multivariable analysis included all baseline comorbidities, insurance status, race, and gender. There is steep progression in amputation rate ranging from 5% at scores of 0 and 1 to >60% for scores in of >10. Area under the curve analysis revealed a value of 0.706. CONCLUSIONS: Patients living in the most disadvantaged socioeconomic neighborhoods have an increased risk of amputation after emergent infrainguinal arterial bypass independent of baseline comorbidities and perioperative events. Baseline comorbidities are not impactful regarding amputation rates after emergent infrainguinal bypass surgery. The need for bypass revision or thrombectomy during the index hospitalization is the most impactful factor toward amputation after emergency bypass. A risk score with quality accuracy has been developed to help identify patients at particularly high likelihood of limb loss, which may aid in counseling regarding heightened vigilance in postoperative and long-term follow-up care.

Analysis of Oklahoma amputation trends and identification of risk factors to target areas for limb preservation interventions.

OBJECTIVE: Annual trends of lower extremity amputation due to end-stage chronic disease are on the rise in the United States. These amputations are leading to massive expenses for patients and the medical system. In Oklahoma, we have a high-risk population because access to care is low, the number of uninsured is high, cardiovascular health is poor, and our overall health care performance is ranked 50th in the country. But we know little about Oklahomans and their risk of limb loss. It is, therefore, imperative to look closely at this population to discover contemporary rates, trends, and state-specific risk factors for amputation due to diabetes and/or peripheral arterial disease (PAD). We hypothesize that state-specific groups will be identified as having the highest risk for limb loss and that contemporary trends in amputations are rising. To create implementable solutions to limb preservation, a baseline must be set. METHODS: We conducted a 12-consecutive-year observational study using Oklahoma's hospital discharge data. Discharges among patients 20 years or older with a primary or secondary diagnosis of diabetes and/or PAD were included. Diagnoses and amputation procedures were identified using International Classification of Disease-9 and -10 codes. Amputation rates were calculated per 1000 discharges. Trends in amputation rates were measured by annual percentage changes (APC). Prevalence ratios evaluated the differences in amputation rates across demographic groups. RESULTS: Over 5,000,000 discharges were identified from 2008 to 2019. Twenty-four percent had a diagnosis of diabetes and/or PAD. The overall amputation rate was 12 per 1000 discharges for those with diabetes and/or PAD. Diabetes and/or PAD-related amputation rates increased from 8.1 to 16.2 (APC, 6.0; 95% confidence interval [CI], 4.7-7.3). Most amputations were minor (59.5%), and although minor, increased at a faster rate compared with major amputations (minor amputation APC, 8.1; 95% CI, 6.7-9.6 vs major amputation APC, 3.1; 95% CI, 1.5-4.7); major amputations were notable in that they were significantly increasing. Amputation rates were the highest among males (16.7), American Indians (19.2), uninsured (21.2), non-married patients (12.7), and patients between 45 and 49 years of age (18.8), and calculated prevalence ratios for each were significant (P = .001) when compared within their respective category. CONCLUSIONS: Amputation rates in Oklahoma have nearly doubled in 12 years, with both major and minor amputations significantly increasing. This study describes a worsening trend, underscoring that amputations due to chronic disease is an urgent statewide health care problem. We also present imperative examples of amputation health care disparities. By defining these state-specific areas and populations at risk, we have identified areas to pursue and improve care. These distinctive risk factors will help to frame a statewide limb preservation intervention.

Prosthetic fitting and mortality after major lower extremity amputation.

BACKGROUND: Studies suggest that ambulation after major lower extremity amputation (LEA) is low and mortality after LEA is high. Successful prosthetic fitting after LEA has a significant quality of life benefit; however, it is unclear if there are benefits in post-LEA mortality. Our objective was to examine a contemporary cohort of patients who underwent LEA and determine if there is an association between fitting for a prosthetic and mortality. METHODS: We reviewed all patients who underwent LEA between 2015 and 2022 at two academic health care systems in a large metropolitan city. The exposure of interest was prosthetic fitting after LEA. The primary outcomes were mortality within 1 and 3 years of follow-up. Ambulation after LEA was defined as being ambulatory with or without an assistive device. Patients with prior LEA were excluded. Extended Cox models with time-dependent exposure were used to evaluate the association between prosthetic fitting and mortality at 1 and 3 years of follow-up. RESULTS: Among 702 patients who underwent LEA, the mean (SD) age was 64.3 (12.6) years and 329 (46.6%) were fitted for prosthetic. The study population was mostly male (n = 488, 69.5%), predominantly non-Hispanic Black (n = 410, 58.4%), and nearly one-fifth were non-ambulatory before LEA (n = 139 [19.8%]). Of note, 14.3% of all subjects who were nonambulatory at some point after LEA, and 28.5% of patients not ambulatory preoperatively were eventually ambulatory after LEA. The rate of death among those fitted for a prosthetic was 12.0/100 person-years at 1 year and 5.8/100 person-years at 3 years of follow-up; among those not fitted for a prosthetic, the rate of death was 55.7/100 person-years and 50.7/100 person-years at 1 and 3 years of follow-up, respectively. After adjusting for several sociodemographic data points, comorbidities, pre- or post- coronavirus disease 2019 pandemic timeframe, and procedural factors, prosthetic fitting is associated with decreased likelihood of mortality within 1 year of follow-up (adjusted hazard ratio, 0.24; 95% confidence interval, 0.14-0.40) as well as within 3 years (adjusted hazard ratio, 0.40; 95% confidence interval, 0.29-0.55). CONCLUSIONS: Prosthetic fitting is associated with improved survival, and preoperative functional status does not always predict postoperative functional status. Characterizing patient, surgical, and rehabilitation factors associated with receipt of prosthetic after LEA may improve long-term survival in these patients. Process measures employed by the Department of Veterans Affairs, such as prosthetic department evaluation of all amputees, may represent a best practice.

Relevance of BEST-CLI trial endpoints in a tertiary care limb preservation program.

OBJECTIVE: Major adverse limb event-free survival (MALE-FS) differed significantly by initial revascularization approach in the BEST-CLI randomized trial. The BEST-CLI trial represented a highly selected subgroup of patients seen in clinical practice; thus, we examined the endpoint of MALE-FS in an all-comers tertiary care practice setting. METHODS: This is a single-center retrospective study of consecutive, unique patients who underwent technically successful infrainguinal revascularization for chronic limb-threatening ischemia (2011-2021). MALE was major amputation (transtibial or above) or major reintervention (new bypass, open bypass revision, thrombectomy, or thrombolysis). RESULTS: Among 469 subjects, the mean age was 70 years, and 34% were female. Characteristics included diabetes (68%), end-stage renal disease (ESRD) (16%), Wound, Ischemia, and foot Infection (WIfI) stage 4 (44%), Global Limb Anatomic Staging System (GLASS) stage 3 (62%), and high pedal artery calcium score (pMAC) (22%). Index revascularization was autogenous vein bypass (AVB) (30%), non-autogenous bypass (NAB) (13%), or endovascular (ENDO) (57%). The composite endpoint of MALE or death occurred in 237 patients (51%) at a median time of 189 days from index revascularization. In an adjusted Cox model, factors independently associated with MALE or death included younger age, ESRD, WIfI stage 4, higher GLASS stage, and moderate-severe pMAC, whereas AVB was associated with improved MALE-FS. Freedom from MALE-FS, MALE, and major amputation at 30 days were 90%, 92%, and 95%; and at 1 year were 63%, 70%, and 83%, respectively. MALE occurred in 144 patients (31%) and was associated with ESRD, WIfI stage, GLASS stage, pMAC score, and index revascularization approach. AVB had superior durability, with adjusted 2-year freedom from MALE of 72%, compared with 66% for ENDO and 51% for NAB. Within the AVB group, spliced vein conduit had higher MALE compared with single-segment vein (hazard ratio, 1.8; 95% confidence interval, 0.9-3.7; P = .008 after inverse propensity weighting), but there was no statistically significant difference in major amputation. Of the 144 patients with any MALE, the first MALE was major reintervention in 47% and major amputation in 53%. Major amputation as first MALE was associated with non-AVB index approach. Indications for major reintervention were symptomatic stenosis/occlusion (54%), lack of clinical improvement (28%), asymptomatic graft stenosis (16%), and iatrogenic events (3%). Conversion to bypass occurred after 6% of ENDO cases, two-thirds of which involved distal bypass targets at the ankle or foot. CONCLUSIONS: In this consecutive, all-comers cohort, disease complexity was associated with procedural selection and MALE-FS. AVB independently provided the greatest MALE-FS and freedom from MALE and major amputation. Compared with the BEST-CLI randomized trial, MALE after ENDO in this series was more frequently major amputation, with relatively few conversions to open bypass.

The natural history of isolated common femoral endarterectomy for chronic limb-threatening ischemia.

OBJECTIVE: Occlusive disease of the common femoral artery can generate profound lower extremity ischemia as the normal collateral pathways from the profunda to the superficial femoral artery cannot adequately develop. In patients with lifestyle-limiting claudication, isolated common femoral endarterectomy (CFE) is highly effective. Because CFE does not provide direct, in-line flow to the plantar arch, it has been felt to provide inadequate revascularization to patients with chronic limb-threatening ischemia (CLTI). The purpose of this retrospective clinical study was to report and assess the natural history of selected patients with CLTI treated with isolated CFE (without concomitant infrainguinal revascularization). METHODS: Consecutive CFEs performed in a large, urban hospital for CLTI between 2014 and 2021 were reviewed. Patient characteristics, limb, and anatomical stages using the Wound, Ischemia, foot Infection (WIfI) and Global Limb Anatomic Staging System were tabulated. Limb-specific and survival-related end points were analyzed. RESULTS: Fifty-eight patients presenting with CLTI underwent isolated CFE (mean age, 74 ± 10 years; 62% male, 90% current or prior smoker). Comorbidities included diabetes (52%), coronary artery disease (55%), congestive heart failure (22%), and end-stage renal failure on hemodialysis (5%). Patients presented with either rest pain (36%) or tissue loss (64%); the latter group exhibited advanced limb threat (68% in WIfI stage 3 or 4). The majority of patients had associated severe infrainguinal disease (50% Global Limb Anatomic Staging Systems 3). After a median follow-up of 17 months (range, 10-29 months), vascular reintervention was required in 7 patients (12%). One patient (2%) required major limb amputation after presentation in WIfI stage 4 (W3I3fI0). Indeed, WIfI stage 4 was a significant univariate predictor of the need for subsequent infrainguinal bypass (P = .034). CONCLUSIONS: Isolated CFE as primary therapy in highly selected patients with CLTI was safe and effective. Index limb stage is predictive of the need for associated infrainguinal revascularization in this complex population.

Infra-inguinal bypass surgery vs endovascular revascularization for chronic limb-threatening ischemia in average- and high-risk patients.

OBJECTIVE: This study aimed to evaluate treatment outcomes after bypass surgery or endovascular therapy (EVT) in average- and high-risk patients with chronic limb-threatening ischemia (CLTI). METHODS: We retrospectively analyzed multicenter data of patients who underwent infra-inguinal revascularization for CLTI between 2015 and 2022. A high-risk patient was defined as one with estimated 30-day mortality rate ≥5% or 2-year survival rate ≤50%, as determined by the Surgical Reconstruction vs Peripheral Intervention in Patients With Critical Limb Ischemia (SPINACH) calculator. The amputation-free survival (AFS), limb salvage (LS), wound healing, and 30-day mortality were compared separately for the average- and high-risk patients between the bypass and EVT with propensity score matching. RESULTS: We analyzed 239 and 31 propensity score-matched pairs in the average- and high-risk patients with CLTI. In the average-risk patients, the 2-year AFS and LS rates were 78.1% and 94.4% in the bypass group and 63.0% and 87.7% in the EVT group (P < .001 and P = .007), respectively. The 1-year wound healing rates were 88.6% in the bypass group and 76.8% in the EVT group, respectively (P < .001). The 30-day mortality was 0.8% in the bypass surgery and 0.8% in the EVT group (P = .996). In the high-risk patients, there was no differences in the AFS, LS, and wound healing between the groups (P = .591, P = .148, and P = .074). The 30-day mortality was 3.2% in the bypass group and 3.2% in the EVT group (P = .991). CONCLUSIONS: Bypass surgery is superior to EVT with respect to the AFS, LS, and wound healing in the average-risk patients. EVT is a feasible first-line treatment strategy for high-risk patients with CLTI undergoing revascularization, based on the lack of significant differences in the 2-year AFS rate, between the bypass surgery and EVT cohorts.

Comparison of limb outcomes between bypass surgery and endovascular therapy in dialysis-dependent and -independent patients with chronic limb-threatening ischemia.

OBJECTIVE: To examine limb salvage (LS) and wound healing in dialysis-dependent and -independent patients with chronic limb-threatening ischemia (CLTI) after infrainguinal bypass surgery or endovascular therapy (EVT). METHODS: We retrospectively analyzed the multi-center data of patients who underwent infrainguinal revascularization for CLTI with Wound, Ischemia, and foot Infection (WIfI) stage 2 to 4 between 2015 and 2020. The primary endpoint was LS. The secondary endpoint included wound healing, amputation-free survival (AFS), periprocedural complications, and 2-year survival. Comparison of these outcomes were made after propensity score matching. RESULTS: We analyzed 252 dialysis-dependent (318 limbs) and 305 dialysis-independent (354 limbs) patients. Propensity score matching extracted 202 pairs with no significant differences in characteristics. The LS rate in bypass surgery was better than that in EVT in dialysis-dependent patients (P < .001). There was no significant difference in the LS rates between bypass surgery and EVT in dialysis-independent patients (P = .168). The wound healing rate of bypass surgery was better than that of EVT both dialysis-dependent and -independent patients with CLTI. The AFS rate of bypass surgery was better than that of EVT in dialysis-dependent patients (P < .001). There was no significant difference in the AFS rates between bypass surgery and EVT in dialysis-independent patients (P = .099). There was no significant difference in the occurrence of Clavien-Dindo ≥ IV and V between bypass surgery and EVT in dialysis-dependent and -independent patients. Age ≥75 years, serum albumin levels <3.5 g/dL, and non-ambulatory status were risk factors for 2-year mortality in dialysis-dependent patients. The 2-year survival rates in dialysis-dependent patients with risk factors of 0, 1, 2, and 3 were 82.5%, 67.1%, 49.5%, and 10.2%, respectively (P < .001). CONCLUSIONS: For LS and wound healing, bypass surgery was preferred for revascularization in dialysis-dependent patients with WIfI stage 2 to 4. Although dialysis dependency was one of the risk factors for 2-year mortality, dialysis-dependent patients, who have 0 to 1 risk factors, may benefit from bypass surgery, as 2-year survival of >50% is expected.