Clinical success using patient-oriented outcome measures after lower extremity bypass and endovascular intervention for ischemic tissue loss

Neutrophil-lymphocyte ratio (NLR); an accurate inflammatory marker to predict diabetic foot ulcer amputation: a matched case-control study

BACKGROUND

Diabetic foot ulcer (DFU) is a well-known complication of diabetes. The main therapeutic options for treating DFU include surgical debridement. However, conditions such as sensory loss and insufficient blood supply can lead to lower extremity amputations. Inflammatory biomarkers, including the neutrophil‒lymphocyte ratio (NLR) and platelet‒lymphocyte ratio (PLR), have shown promise in predicting the development of diabetes complications.

METHODS

This study included 126 individuals with known DFUs who underwent amputation or debridement surgery during hospitalization between January 2017 and December 2022. The participants were divided into two groups, each containing 63 patients, based on the treatment they received. Analyses were conducted via univariate and multivariate regression models. The linearity of the relationship between each inflammatory index and the risk of amputation was further examined via restricted cubic spline (RCS) curves with four knots.

RESULTS

Categorical regression analysis showed an elevated risk of amputation in patients with an NLR greater than 6.08, with an OR of 13.090 (95% CI: 5.143-33.320, P < 0.001), compared with those with an NLR less than 6.08. Additionally, patients with a PLR greater than 210 demonstrated a similarly elevated risk of amputation with an OR of 2.31 (95% CI: 1.066‒4.669, P = 0.033); however, those with lymphocyte‒white blood cell ratio (LWR) levels of greater than 0.1265 exhibited reduced likelihood of having amputation (OR: 0.092 (95% CI: 0.038‒0.226, P < 0.001)).

CONCLUSIONS

This study supports that NLR, PLR and LWR may have value as a predictive marker for amputation in patients with DFUs.

Population-Based Trends in Amputations and Revascularizations for Peripheral Artery Disease From 1990 to 2009

OBJECTIVE

To determine trends in amputations and revascularizations for peripheral artery disease (PAD) in a well-defined population.

METHODS

A population-based cohort study of Olmsted County, Minnesota, residents with PAD undergoing amputation or revascularization was conducted between January 1, 1990, and December 31, 2009. Population-level 5-year incidence trends for endovascular, open surgical, and hybrid revascularizations and major and minor amputations were determined. Limb-specific outcomes after revascularization, including major adverse limb events and amputation-free survival, were compared between initial surgical and endovascular or hybrid revascularization groups using Kaplan-Meier analysis.

RESULTS

We identified 773 residents who underwent 1906 limb-procedures, including 689 open revascularizations, 685 endovascular or hybrid revascularizations, and 220 major amputations. During the 20-year study period, the incidence of endovascular and hybrid revascularizations increased, whereas the incidence of open surgical revascularizations and major amputations decreased. Incidence of revascularizations for chronic limb-threatening ischemia (CLTI) did not change. Among residents with CLTI undergoing their first revascularization on a limb, endovascular revascularization was associated with more major adverse limb events and major amputations compared with surgical revascularization during the ensuing 15 years.

CONCLUSION

The rising incidence of endovascular and hybrid revascularizations and the decreasing incidence of open surgical revascularizations for PAD were associated with a decreasing incidence of major amputations in this population between 1990 and 2009, despite a stable incidence of revascularizations for CLTI. With more major adverse limb events and major amputations after endovascular revascularization, these trends suggest that additional emphasis should be placed on improving limb salvage efforts beyond just mode of revascularization.

Patient-centered clinical success after lower extremity revascularization for complex diabetic foot wounds treated in a multidisciplinary setting

OBJECTIVE

Physician-oriented outcomes, such as patency and amputation-free survival (AFS), have traditionally been markers of success after lower extremity revascularization. Previous studies have defined clinical success based on a composite of patient-centered outcomes and have shown this outcome to be achieved in less than 50% of patients, far lower than standard physician-oriented outcomes. The purpose of this study is to evaluate clinical success after lower extremity bypass (LEB) or peripheral vascular intervention (PVI) for tissue loss in diabetic patients treated in a multidisciplinary setting to better understand what factors are associated with success from a patient's perspective.

METHODS

All patients presenting to our multidisciplinary diabetic limb preservation service from July 2012 to January 2020 were enrolled in a prospective database. Patients who underwent either LEB or PVI for ulcer or gangrene were included in the analysis. Clinical success was defined as the composite outcome of secondary patency to the point of wound healing, limb salvage for 1 year, maintenance of ambulatory status for 1 year, and survival for 6 months. Secondary outcomes included 1-year wound healing, patency, and AFS.

RESULTS

A total of 134 revascularizations were performed in 131 patients, including 91 (68%) PVI and 43 (32%) LEB. Patients were more frequently male (64%) and black (61%), and 16% were dialysis-dependent. All patients had tissue loss (53% ulcer, 47% gangrene). There were 5 (3.7%) wound, ischemia, and foot infection stage 1, 6 (6.0%) stage 2, 29 (22%) stage 3, and 92 (69%) stage 4 limbs at the time of revascularization. Overall, 76.9% of patients preserved secondary patency to the point of wound healing, 92.5% had limb salvage for 1 year, 90.3% had maintenance of ambulatory status for 1 year, and 96.3% survived for 6 months. The clinical success composite outcome was achieved in 71.6% of patients and was not statistically different between those undergoing PVI vs LEB (69.2% vs 76.7%, P = .37). Secondary patency, limb salvage, and AFS at 1 year were 80.8% ± 3.6%, 91.8% ± 2.3%, and 83.3% ± 3.1%, respectively. Wound healing at 1 year was 84.3% ± 3.4%. The only covariate associated with clinical failure on multivariable analysis was increased age (odds ratio, 0.95; 95% confidence interval, 0.91-0.99; P = .008).

CONCLUSIONS

Among diabetic patients presenting with tissue loss, the composite outcome of patient-centered clinical success is lower than traditional physician-centered outcomes after lower extremity revascularization, mostly due to low rates of secondary patency to the point of wound healing. In the current study, clinical failure was only associated with older age and was no different after PVI compared with LEB.

Analysis of a Machine Learning-Based Risk Stratification Scheme for Chronic Limb-Threatening Ischemia

IMPORTANCE

Valid risk stratification schemes are key to performing comparative effectiveness research; however, for chronic limb-threatening ischemia (CLTI), risk stratification schemes have limited efficacy. Improved, accurate, comprehensive, and reproducible risk stratification models for CLTI are needed.

OBJECTIVE

To evaluate the use of topic model cluster analysis to generate an accurate risk prediction model for CLTI.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, nested cohort study of existing Project of Ex Vivo Vein Graft Engineering via Transfection (PREVENT) III clinical trial data assessed data from patients undergoing infrainguinal vein bypass for the treatment of ischemic rest pain or ischemic tissue loss. Original data were collected from January 1, 2001, to December 31, 2003, and were analyzed in September 2021. All patients had 1 year of follow-up.

EXPOSURES

Supervised topic model cluster analysis was applied to nested cohort data from the PREVENT III randomized clinical trial. Given a fixed number of clusters, the data were used to examine the probability that a patient belonged to each of the clusters and the distribution of the features within each cluster.

MAIN OUTCOMES AND MEASURES

The primary outcome was 1-year CLTI-free survival, a composite of survival with remission of ischemic rest pain, wound healing, and freedom from major lower-extremity amputation without recurrent CLTI.

RESULTS

Of the original 1404 patients, 166 were excluded because of a lack of sufficient feature and/or outcome data, leaving 1238 patients for analysis (mean [SD] age, 68.4 [11.2] years; 800 [64.6%] male; 894 [72.2%] White). The Society for Vascular Surgery Wound, Ischemia, and Foot Infection grade 2 wounds were present in 543 patients (43.8%), with rest pain present in 645 (52.1%). Three distinct clusters were identified within the cohort (130 patients in stage 1, 578 in stage 2, and 530 in stage 3), with 1-year CLTI-free survival rates of 82.3% (107 of 130 patients) for stage 1, 61.1% (353 of 578 patients) for stage 2, and 53.4% (283 of 530 patients) for stage 3. Stratified by stage, 1-year mortality was 10.0% (13 of 130 observed deaths in stage 1) for stage 1, 13.5% (78 of 578 patients) for stage 2, and 20.2% (105 of 521 patients) for stage 3. Similarly, stratifying by stage revealed major limb amputation rates of 4.2% (5 of 119 observed major limb amputations in stage 1) for stage 1, 10.8% (55 of 509 patients) for stage 2, and 18.4% (81 of 440 patients) for stage 3. Among survivors without a major amputation, the rates of CLTI recurrence were 9.2% (11 of 119 observed recurrences in stage 1) for stage 1, 24.9% (130 of 523 patients) for stage 2, and 29.6% (132 of 446 patients) for stage 3.

CONCLUSIONS AND RELEVANCE

The topic model cluster analysis in this cohort study identified 3 distinct stages within CLTI. Findings suggest that CLTI-free survival is an end point that can be accurately and reproducibly quantified and may be used as a patient-centric outcome.

Predictors of outcome in diabetic patients undergoing infrapopliteal endovascular revascularization for chronic limb-threatening ischemia

OBJECTIVE

The incidence of chronic limb-threatening ischemia in diabetic patients is increasing. The factors influencing outcome after infrapopliteal revascularization in these patients are largely unknown. Therefore, this study aims to identify the impact of perioperative glucose control on the long-term outcomes in this patient cohort, and furthermore to identify other factors independently associated with outcome.

METHODS

Consecutive diabetic patients undergoing infrapopliteal endovascular revascularization for chronic limb-threatening ischemia were identified. Patients' demographics, procedural details, daily capillary blood glucose, and hemoglobin A1C levels were collected and analyzed against the study end points using Kaplan-Meier and Cox regression analysis.

RESULTS

A total of 437 infrapopliteal target vessels were successfully crossed in 203 patients. Amputation-free survival by Kaplan-Meier (estimate (standard error)%) was 74 (3.3)% and 63 (3.7)%, primary patency was 61 (4.2)% and 50 (4.9)%, assisted primary patency was 69 (5.2)% and 55 (6.1)%, and secondary patency was 71 (3.8)% and 59 (4.1)% at 1 year and 2 years, respectively. Cox regression analysis showed high perioperative capillary blood glucose levels to be an independent predictor of binary restenosis (hazard ratio [HR], 1.49; 95% confidence interval [CI], 1.31-1.1.78; P = .015). Postprocedural dual-antiplatelet therapy was found to be an independent predictor of amputation-free survival (HR, 1.69; 95% CI, 1.04-2.75; P = .033), and freedom from major adverse limb events (HR: 1.96; 95% CI, 1.16-3.27; P = .023) and baseline estimated glomerular filtration rate was significantly associated with better amputation-free survival (HR, 0.52; 95% CI, 0.31-0.87; P = .014).

CONCLUSIONS

Poor perioperative glycemic control is associated with a higher incidence of restenosis after infrapopliteal revascularization in diabetic patients. Dual antiplatelet therapy is associated with better outcomes in this group.

Current opinion on the role of the foot perfusion in limb amputation risk assessment

The most important and consulted guidelines dealing with not healing foot ulcers suggest the measurement of the foot perfusion (FP) to exclude the critical limb ischemia (CLI), because of the high risk of limb amputation. But the recommended cut-off values of FP fail to include all the heterogeneity of patients of the real-life with a not healing ulcer. Often these patients are diabetics with a moderate PAD but with a high level of infection. To meet this goal, in 2014, the Society for Vascular Surgery has published the "Lower Extremity Threatened Limb Classification System: Risk stratification based on Wound, Infection, and foot Ischemia (WIfI)." This new classification system has changed the criteria of assessment of limb amputation risk, replacing the single cut-off value role with a combination of a spectrum of perfusion values along with graded infection and dimension levels of skin ulcers. The impact of this new classification system was remarkable so to propose the substitution of the CLI definition, with the new Critical limb-threatening ischemia (CLTI), that seems to define the limb amputation risk more realistically.

Discrepancy in Outcomes after Revascularization for Chronic Limb-Threatening Ischemia Warrants Separate Reporting of Rest Pain and Tissue Loss

BACKGROUND

Chronic limb-threatening ischemia (CLTI) manifests as rest pain (RP) and tissue loss (TL). Outcomes of lower extremity revascularization (LER) for CLTI have traditionally been evaluated as a single entity and compared with claudication. We hypothesize that patients presenting with TL have worse short-term outcomes after LER, compared to patients with RP.

METHODS

The National Inpatient Sample was reviewed between 2009 and 2013. All patients undergoing LER for TL and RP were identified. Patient characteristics, Charlson Comorbidity Index (CCI), length of stay, rates of inpatient major amputation, and mortality after LER were noted. Multivariable regression analysis was performed to identify predictors of inpatient mortality and major amputation between the 2 groups.

RESULTS

A total of 218,628 patients underwent LER (RP = 76,108, TL = 142,519). Patients with TL were more likely to undergo endovascular LER (RP = 31.3% vs. TL = 48.7%; P < 0.001). Patients with TL had higher comorbidities as suggested by increased likelihood of having CCI ≥3 (RP = 22.9% vs. TL = 40.3%; P < 0.001). The mean costs were significantly higher in the TL group (RP = $23,795 vs. TL = $31,470; P < 0.001). There was a significantly higher rate of major amputation (RP = 1.3% vs. TL = 6.6%; P < 0.001) and inpatient mortality (RP = 0.9% vs. TL = 1.9%; P < 0.001) after LER for TL. On multivariable analysis, TL was independently associated with increased major amputation (odds ratio [OR] 4.93, 95% confidence interval [CI] 4.18-5.81) and increased mortality (OR 1.42, 95% CI 1.16-1.74) compared to RP.

CONCLUSIONS

There is significant discrepancy in outcomes of LER for TL and RP. TL is independently associated with major amputation and inpatient mortality. Outcomes of LER for TL and RP should be reported separately for better benchmarking.

Derivation and validation of a clinical prediction model for assessing the risk of lower extremity amputation in patients with type 2 diabetes

AIM

This study aims to develop and validate a lower extremity amputation (LEA) risk score system in persons with type 2 diabetes.

METHODS

A retrospective population-based cohort study was conducted among eligible 21,484 participants in the derivation set and 10,742 participants in the validation set who were enrolled in the Taiwan National Diabetes Care Management Program. The risk score system was developed following the steps proposed by the Framingham Heart Study with a Cox proportional hazards model algorithm. Discrimination ability was assessed by the receiver operating characteristic curve, and calibration was performed by Hosmer-Lemeshow test.

RESULTS

A total of 504 patients developed LEA at an average follow-up of 7.4 years. The point scores were derived from 15 predictors as follows: age, gender, duration of type 2 diabetes, body mass index, HbA1c, triglyceride, eGFR, variation of fasting blood glucose, comorbidities of stroke, diabetes retinopathy, hypoglycemia and foot ulcer, anti-diabetes medication, and use of diuretics and nitrates. The c-statistics for predicting 3-, 5-, and 8-year LEA risks were 0.80 [95% confidence interval (CI) 0.76-0.83], 0.78 (0.75-0.81), and 0.76 (0.74-0.79) in the derivation set, respectively, and 0.81 (0.76-0.85), 0.77 (0.73-0.81), and 0.74 (0.71-0.77) in the validation set, respectively.

CONCLUSIONS

A new risk score for LEA was developed and validated in the clinical setting with good discriminatory ability. Poor glycemic control, glucose variation, comorbidities, and medication use were identified as predictive factors for LEA in patients with type 2 diabetes.

Efficacy Outcomes of Endovascular Versus Surgical Revascularization in Critical Limb Ischemia: Results From a Prospective Cohort Study

Data on efficacy outcomes of endovascular versus surgical revascularization in patients with critical limb ischemia (CLI) in contemporary practice are limited. In this prospective cohort study, 353 consecutive patients with CLI were enrolled and allocated to endovascular (PTA [percutaneous transluminal angioplasty]), surgical (SURG), or no revascularization (No REVASC) after interdisciplinary consensus. Outcome measures were sustained primary clinical success (sPCS; survival without major amputation, repeated target extremity revascularization, and freedom from CLI), limb salvage, and amputation-free survival. Propensity-matched Kaplan-Meier analyses and stratified log-rank tests were performed. The PTA, SURG, and No REVASC groups consisted of 264, 62, and 27 patients, respectively. Compared to SURG patients, PTA patients were significantly older, had more risk factors, and more often had ischemic lesions. Propensity score-adjusted analyses showed no significant differences: sPCS was 51.3%/52.2%, limb salvage rate 91.5%/93.7%, and major amputation-free survival 90.5%/87.2% at 12 months for PTA and SURG, respectively. Amputation-free survival for the No REVASC group was 69% at 12 months. In conclusion, endovascular and surgical revascularization in CLI has comparable efficacy outcomes after 12 months. Contemporary overall outcome of patients with CLI is considerably better compared to earlier studies.

Quality of time spent without symptoms of disease or toxicity of treatment for transmetatarsal amputation versus digital amputation in diabetic patients with digital gangrene

Aim

We aim to compare the outcome of diabetic patients with gangrenous toes who were managed initially either by digital amputation or by transmetatarsal amputation. The null hypothesis is that transmetatarsal amputation had less theatre trips and better healing.

Materials and Methods

A parallel observational comparative study of all diabetic patients who underwent either digital or transmetatarsal amputation in a tertiary referral center from 2002 through 2015. Comorbid conditions, subsequent amputations, hospital stay, and readmission were noted.

Results

A total of 223 patients underwent minor amputation during the study period, of which 147 patients were diabetic and 76 patients were non-diabetic. Seventy-seven patients had digital amputation and 70 transmetatarsal amputation in diabetic patients. Demographics were similar in both groups. The median time to major amputation was (400 ± IQR 1205 days) in the digital amputation group, compared to 690 ± IQR 891 days in the transmetatarsal amputation group ( P = 0.974). 29.9% of digital amputations and 15.7% of transmetatarsal amputations in diabetic patients, required minor amputations or revision procedures ( P = 0.04). Median length of hospital stay was (20 days, IQR 27) in the digital group and (17 days, IQR17) in the transmetatarsal amputation group ( P = 0.17). Need for re-admission was 48.1% in digital patients compared to 50% in transmetatarsal amputation patients ( P = 0.81). Quality of time spent without symptoms of disease or toxicity of treatment (Q-TWiST) was (315 days, IQR 45) in digital group and (346 days, IQR 48) in the transmetatarsal amputation patients ( P = 0.099).

Conclusion

Despite the lack of statistical significance, transmetatarsal amputation offered better outcome in the diabetic patients, with less re-intervention rate, shorter hospital stays, less theatre trips, and longer time without toxicity (TWiST).

Pre-operative predictors of poor outcomes in patients undergoing surgical lower extremity revascularisation - Retrospective cohort study

BACKGROUND

Surgical lower extremity revascularisation (LER) can lead to poor outcomes that include delayed hospital discharge, in-hospital mortality, major amputations and readmissions. The aim of this study was to identify pre-operative predictors associated with these poor clinical outcomes.

MATERIALS AND METHODS

All patients (n = 635; mean age 69; male 67.4%) who underwent surgical LER over a 5 year period in a single tertiary vascular institution were identified. Patients considered to have suffered a poor outcome (Group A) included all in-hospital mortality and major amputations, delayed discharges with a length of stay (LOS) over one standard deviation above the mean or any readmission under any specialty within 12 months. Group A included 247 patients (38.9%) and the good outcome group included the remaining 388 patients (61.1%) from which a sample of 99 patients were selected as controls (Group B).

RESULTS

Mean LOS for the entire study group was 14.4 ± 17.5 days, 12 month readmission rate was 29.1% and in-hospital mortality and major amputation rate was 2.7% and 1.4%, respectively. Pre-admission residence other than own home (OR 9.0; 95% CI 1.2-70.1; P = 0.036), atherosclerotic disease burden (OR 2.2; 95% CI 1.3-3.8; P = 0.003) and tissue loss (OR 3.0; 95% CI 1.6-5.3; P < 0.001) were identified as independent, statistically significant pre-operative predictors of poor outcome. Following discharge, group B patients had a significantly higher rate of amputation free survival and graft infection free survival (P < 0.001) compared to group A.

CONCLUSION

Recognition of pre-operative predictors of poor outcome should inform case selection and identify high risk patients requiring intensive perioperative optimisation and post discharge follow up.

Diabetes, lower-extremity amputation, and death

OBJECTIVE

The goal of the study was to determine whether complications of diabetes well-known to be associated with death such as cardiovascular disease and renal failure fully explain the higher rate of death in those who have undergone a lower-extremity amputation (LEA).

RESEARCH DESIGN AND METHODS

This was a longitudinal cohort study of patients cared for in the Health Improvement Network. Our primary exposure was LEA and outcome was all-cause death. Our "risk factor variables" included a history of cardiovascular disease (a history of myocardial infarctions, cerebrovascular accident, and peripheral vascular disease/arterial insufficiency), Charlson index, and a history of chronic kidney disease. We estimated the effect of LEA on death using Cox proportional hazards models.

RESULTS

The hazard ratio (HR) for death after an LEA was 3.02 (95% CI 2.90, 3.14). The fully adjusted (all risk factor variables) LEA HR was diminished only by ∼22% to 2.37 (2.27, 2.48). Furthermore, LEA had an area under the receiver operating curve (AUC) of 0.51, which is poorly predictive, and the fully adjusted model had an AUC of 0.77, which is better but not strongly predictive. Sensitivity analysis revealed that it is unlikely that there exists an unmeasured confounder that can fully explain the association of LEA with death.

CONCLUSIONS

Individuals with diabetes and an LEA are more likely to die at any given point in time than those who have diabetes but no LEA. While some of this variation can be explained by known complications of diabetes, there remains a large amount of unexplained variation.

Functional outcomes after lower extremity revascularization in nursing home residents: a national cohort study

IMPORTANCE

Lower extremity revascularization often seeks to allow patients with peripheral arterial disease to maintain the ability to walk, a key aspect of functional independence. Surgical outcomes in patients with high levels of functional dependence are poorly understood.

OBJECTIVE

To determine functional status trajectories, changes in ambulatory status, and survival after lower extremity revascularization in nursing home residents.

DESIGN

Using full Medicare claims data for 2005 to 2009, we identified nursing home residents who underwent lower extremity revascularization. With the Minimum Data Set for Nursing Homes activities of daily living summary score, we examined changes in their ambulatory and functional status after surgery. We identified patient and surgery characteristics associated with a composite measure of clinical and functional failure-death or nonambulatory status 1 year after surgery.

SETTING

All nursing homes in the United States participating in Medicare or Medicaid.

PARTICIPANTS

Nursing home residents who underwent lower extremity revascularization.

MAIN OUTCOMES AND MEASURES

Functional status, ambulatory status, and death.

RESULTS

During the study period, 10,784 long-term nursing home residents underwent lower extremity revascularization. Prior to surgery, 75% of the residents were not walking; 40% had experienced functional decline. One year after surgery, 51% of patients had died, 28% were nonambulatory, and 32% had sustained functional decline. Among 1672 residents who were ambulatory before surgery, 63% had died or were nonambulatory at 1 year; among 7188 who were nonambulatory, 89% had died or were nonambulatory. After multivariate adjustment, factors independently associated with death or nonambulatory status were 80 years or older (adjusted hazard ratio [AHR], 1.28; 95% CI, 1.16-1.40), cognitive impairment (AHR, 1.23; 95% CI, 1.18-1.29), congestive heart failure (AHR, 1.16; 95% CI, 1.11-1.22), renal failure (AHR, 1.09; 95% CI, 1.04-1.14), emergent surgery (AHR, 1.29; 95% CI, 1.23-1.35), nonambulatory status before surgery (AHR, 1.88; 95% CI, 1.78-1.99), and decline in activities of daily living before surgery (AHR, 1.23; 95% CI, 1.18-1.28).

CONCLUSIONS AND RELEVANCE

Of nursing home residents in the United States who undergo lower extremity revascularization, few are alive and ambulatory 1 year after surgery. Most who were still alive had gained little, if any, function.

Autologous alternative veins may not provide better outcomes than prosthetic conduits for below-knee bypass when great saphenous vein is unavailable

BACKGROUND

There is a need to better define the role of alternative autologous vein (AAV) segments over contemporary prosthetic conduits in patients with critical limb ischemia when great saphenous vein (GSV) is not available for use as the bypass conduit.

METHODS

Consecutive patients who underwent bypass to infrageniculate targets between 2007 and 2011 were categorized in three groups: GSV, AAV, and prosthetic. The primary outcome was graft patency. The secondary outcome was limb salvage. Cox proportional hazards regression was used to adjust for baseline confounding variables.

RESULTS

A total of 407 infrainguinal bypasses to below-knee targets were analyzed; 255 patients (63%) received a single-segment GSV, 106 patients (26%) received an AAV, and 46 patients (11%) received a prosthetic conduit. Baseline characteristics were similar among groups, with the exception of popliteal targets and anticoagulation use being more frequent in the prosthetic group. Primary patency at 2 and 5 years was estimated at 47% and 32%, respectively, for the GSV group; 24% and 23% for the AAV group; and 43% and 38% for the prosthetic group. Primary assisted patency at 2 and 5 years was estimated at 71% and 55%, respectively, for the GSV group; 53% and 51% for the AAV group; and 45% and 40% for the prosthetic group. Secondary patency at 2 and 5 years was estimated at 75% and 60%, respectively, for the GSV group; 57% and 55% for the AAV group; and 46% and 41% for the prosthetic group. In Cox analysis, primary patency (hazard ratio [HR], 0.55; P < .001; 95% confidence interval [CI], 0.404-0.758), primary assisted patency (HR, 0.57; P = .004; 95% CI, 0.388-0.831), and secondary patency (HR, 0.56; P = .005; 95% CI, 0.372-0.840) were predicted by GSV compared with AAV, but there was no difference between AAV and prosthetic grafts except for the primary patency, for which prosthetic was protective (HR, 0.38; P < .001; 95% CI, 0.224-0.629). Limb salvage was similar among groups.

CONCLUSIONS

AAV conduits may not offer a significant patency advantage in midterm follow-up over prosthetic bypasses.

Optimal management of infrainguinal arterial occlusive disease

Peripheral arterial occlusive disease is becoming a major health problem in Western societies as the population continues to age. In addition to risk of limb loss, the complexity of the disease is magnified by its intimate association with medical comorbidity, especially cardiovascular and cerebrovascular disease. Risk factor modification and antiplatelet therapy are essential to improve long-term survival. Surgical intervention is indicated for intermittent claudication when a patient’s quality of life remains unacceptable after a trial of conservative therapy. Open reconstruction and endovascular revascularization are cornerstone for limb salvage in patients with critical limb ischemia. Recent advances in catheter-based technology have made endovascular intervention the preferred treatment approach for infrainguinal disease in many cases. Nevertheless, lower extremity bypass remains an important treatment strategy, especially for reasonable risk patients with a suitable bypass conduit. In this review, we present a summary of current knowledge about peripheral arterial disease followed by a review of current, evidence-based medical and surgical therapy for infrainguinal arterial occlusive disease.

Management of critical lower limb ischemia in endovascular era: experience from 511 patients

This study aims at the assessment of the achievability of the endovascular treatment of patients with critical limb ischemia (CLI) and the role of bypass in such patient. This is a prospective study conducted on patients with chronic atherosclerotic critical lower limb ischemia presenting to us over a period of 3 years. Patients presenting with nonsalvageable limbs requiring primary major amputation and nonatherosclerotic causes of CLI were excluded. Endovascular treatment was the first choice modality of treatment in revascularization of all patients. Open surgery was offered selectively for patient whom endovascular failed or complicated and for long TransAtlantic Inter-Society Consensus (TASC) II lesions in fit patients. This study included 511 cases of CLI, and the mean age was 64.5 years. Patients with Rutherford IV, V, and VI were 19.25, 60.5, and 19.25%, respectively. The TASC II aortoiliac lesions were as follows: A, B, C, and D in 33.7, 12,15.7, and 38.6%, respectively, and infrainguinal lesions were A, B, C, and D in 3.7, 19, 35.4, and 68.3%, respectively. A total of 78.3% of patients were treated by endovascular totally, while 16% were treated by surgery from the start, 3.7% of endovascular cases were converted to open surgery after failure of endovascular treatment, and 2% was offered hybrid treatment. Crossing of lesions by subintimal and intraluminal was 12.5 and 87.5%, respectively. Technical success in endovascular was 94%; however, we could successfully revascularize 96.8% of all CLI presented in this study by either surgery or endovascular. On 24 months follow-up, primary patency, secondary patency, and limb salvage by percutaneous transluminal angioplasty are 77.8, 84.7, and 90.7%, respectively. Revascularization by endovascular achieves high technical success and limb salvage in CLI, hence should be considered as preferred choice of treatment. However, both endovascular and surgery should not be counteracting each other and using both can revascularize 96.6% of CLI.

Defining utility and predicting outcome of cadaveric lower extremity bypass grafts in patients with critical limb ischemia

OBJECTIVE

Despite poor long-term patency, acceptable limb salvage has been reported with cryopreserved saphenous vein bypass (CVB) for various indications. However, utility of CVB in patients with critical limb ischemia (CLI) remains undefined. The purpose of this analysis was to determine the role of CVB in CLI patients and to identify predictors of successful outcomes.

METHODS

A retrospective review of all lower extremity bypass (LEB) procedures at a single institution was completed, and CVB in CLI patients were further analyzed. The primary end point was amputation-free survival. Secondary end points included primary patency and limb salvage. Life tables were used to estimate occurrence of end points. Cox regression analysis was used to determine predictors of limb salvage.

RESULTS

From 2000 to 2012, 1059 patients underwent LEB for various indications, of whom 81 received CVB for either ischemic rest pain or tissue loss. Mean age (± standard deviation) was 66 ± 10 years (male, 51%; diabetes, 51%; hemodialysis dependence, 12%), and 73% (n = 59) had history of failed ipsilateral LEB or endovascular intervention. None had sufficient autogenous conduit for even composite vein bypass. Infrainguinal CVB (infrapopliteal target, 96%; n = 78) was completed for multiple indications including Rutherford class 4 (42%; n = 34), class 5 (40%; n = 32), and class 6 (18%; n = 15). Eleven (14%) had CLI and concomitant graft infection (n = 8) or acute on chronic ischemia (n = 3). Intraoperative adjuncts (eg, profundaplasty, suprainguinal stent or bypass) were completed in 49% (n = 40) of cases. Complications occurred in 36% (n = 29), with 30-day mortality of 4% (n = 3). Median follow-up for CLI patients was 11.8 (interquartile range, 0.4-28.4) months with corresponding 1- and 3-year actuarial estimated survival (± standard error mean) of 84% ± 4% and 62% ± 6%. Primary patency of CVB for CLI was 27% ± 6% and 17% ± 6% at 1 and 3 years, respectively. Amputation-free survival was 43% ± 6% and 23% ± 6% at 1 and 3 years, respectively, and significantly higher for rest pain (59% ± 9%, 36% ± 10%) compared with tissue loss (31% ± 7%, 14% ± 7%; log-rank, P = .04). Freedom from major amputation after CVB for CLI was 57% ± 6% and 43% ± 7% at 1 and 3 years. Multivariable predictors of limb salvage for the CVB CLI cohort included postoperative warfarin (hazard ratio [HR], 0.4; 95% confidence interval [CI], 0.2-0.8), dyslipidemia (HR, 0.4; 95% CI, 0.2-0.9), and rest pain (HR, 0.4; 95% CI, 0.2-0.9). Predictors of major amputation included graft infection (HR, 3.1; 95% CI, 1.1-9.0).

CONCLUSIONS

In CLI patients with no autologous conduit and prior failed infrainguinal bypass, CVB outcomes are disappointing. CVB performs best in patients with rest pain, particularly those who can be anticoagulated with warfarin. However, it may be an acceptable option in patients with minor tissue loss or concurrent graft infection, but consideration should be weighed against the known natural history of nonrevascularized CLI and nonbiologic conduit alternatives, given potential cost implications.

Objective measurement of lower extremity function and quality of life after surgical revascularization for critical lower extremity ischemia

BACKGROUND

Outcomes of revascularization for critical limb ischemia (CLI) have historically been patency, limb salvage, and survival. Functional status and quality of life have not been well described. This study used functional and quality of life assessments to measure patient-centered outcomes after revascularization for CLI.

METHODS

The study observed 18 patients (age, 65 ± 11 years) prospectively before and after lower extremity bypass for CLI. Patients completed the Short Physical Performance Battery, which measures walking speed, leg strength, and balance, as well as performed a 6-minute walk, and calorie expenditure was measured by an accelerometer. Isometric muscle strength was assessed with the Muscle Function Evaluation chair (Metitur, Helsinki, Finland). Quality of life instruments included the 36-Item Short Form Health Survey and the Vascular Quality of Life questionnaire. Patients' preoperative status was compared with 4-month postoperative status.

RESULTS

Muscle Function Evaluation chair measurements of ipsilateral leg strength demonstrated a significant increase in knee flexion from 64 ± 62 N to 135 ± 133 N (P = .038) and nearly significant increase in knee extension from 120 ± 110 N to 186 ± 85 N (P = .062) and ankle plantar flexion from 178 ± 126 N to 267 ± 252 N (P = .078). In the contralateral leg, knee flexion increased from 71 ± 96 N to 149 ± 162 N (P = .028) and knee extension from 162 ± 112 N to 239 ± 158 N (P = .036). Absolute improvements were noted in 6-minute walk distance, daily calorie expenditure, and individual domains and overall Short Physical Performance Battery scores, and upper extremity strength decreased, although none were significant. The Vascular Quality of Life questionnaire captured significant improvement in all individual domains and overall score (P < .015). Significant improvement was noted only for bodily pain (P = .011) on the 36-Item Short Form Health Survey.

CONCLUSIONS

Despite lack of statistical improvement in most functional test results, revascularization for CLI results in improved patient-perceived leg function. Significant improvements in isometric muscle strength may explain the measured improvement in quality of life after revascularization for CLI.

Comparative effectiveness of endovascular and surgical revascularization for patients with peripheral artery disease and critical limb ischemia: systematic review of revascularization in critical limb ischemia

BACKGROUND

For patients with critical limb ischemia (CLI), the optimal treatment to enhance limb preservation, prevent death, and improve functional status is unknown. We performed a systematic review and meta-analysis to assess the comparative effectiveness of endovascular revascularization and surgical revascularization in patients with CLI.

METHODS

We systematically searched PubMed, Embase, and the Cochrane Database of Systematic Reviews for relevant English-language studies published from January 1995 to August 2012. Two investigators screened each abstract and full-text article for inclusion, abstracted the data, and performed quality ratings and evidence grading. Random-effects models were used to compute summary estimates of effects, with endovascular treatment as the control group.

RESULTS

We identified a total of 23 studies, including 1 randomized controlled trial, which reported no difference in amputation-free survival at 3 years (odds ratio [OR] 1.22, 95% CI 0.84-1.77) and all-cause mortality (OR 1.07, 0.73-1.56) between the 2 treatments. Meta-analysis of the observational studies showed a statistically nonsignificant reduction in all-cause mortality at 6 months (11 studies, OR 0.85, 0.57-1.27) and amputation-free survival at 1 year (2 studies, OR 0.76, 0.48-1.21) in patients treated with endovascular revascularization. There was no difference in overall death, amputation, or amputation-free survival at ≥2 years.

CONCLUSIONS

The currently available literature suggests that there is no difference in clinical outcomes for patients with CLI treated with endovascular or surgical revascularization. There is a paucity of high-quality data available to guide clinical decision making, especially as it pertains to patient subgroups or anatomical considerations.

The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System: risk stratification based on wound, ischemia, and foot infection (WIfI)

Critical limb ischemia, first defined in 1982, was intended to delineate a subgroup of patients with a threatened lower extremity primarily because of chronic ischemia. It was the intent of the original authors that patients with diabetes be excluded or analyzed separately. The Fontaine and Rutherford Systems have been used to classify risk of amputation and likelihood of benefit from revascularization by subcategorizing patients into two groups: ischemic rest pain and tissue loss. Due to demographic shifts over the last 40 years, especially a dramatic rise in the incidence of diabetes mellitus and rapidly expanding techniques of revascularization, it has become increasingly difficult to perform meaningful outcomes analysis for patients with threatened limbs using these existing classification systems. Particularly in patients with diabetes, limb threat is part of a broad disease spectrum. Perfusion is only one determinant of outcome; wound extent and the presence and severity of infection also greatly impact the threat to a limb. Therefore, the Society for Vascular Surgery Lower Extremity Guidelines Committee undertook the task of creating a new classification of the threatened lower extremity that reflects these important considerations. We term this new framework, the Society for Vascular Surgery Lower Extremity Threatened Limb Classification System. Risk stratification is based on three major factors that impact amputation risk and clinical management: Wound, Ischemia, and foot Infection (WIfI). The implementation of this classification system is intended to permit more meaningful analysis of outcomes for various forms of therapy in this challenging, but heterogeneous population.

Controlled Reperfusion Versus Conventional Treatment of the Acutely Ischemic Limb

Background—

Amputation rates and mortality in patients with severe acute limb ischemia remain high. The protective effect of controlled reperfusion (CR) on tissue damage because of local and systemic reperfusion injury is unclear.

Methods and Results—

A total of 174 patients from 14 centers were randomized between conventional treatment (CT) by thrombembolectomy and normal blood reperfusion and thrombembolectomy followed by CR. The primary end point was amputation-free survival (AFS) after 4 weeks (CT, 82.4%; CR, 82.6%). Secondary end points were AFS (CT, 62.4%; CR, 63.1%) and overall survival (CT, 71.6%; CR, 76.3%) after 1 year. Analysis of the prognostic effects of preoperative factors revealed a strong adverse effect of bilateral involvement on AFS. In the subgroup with unilateral ischemia (n=160), age >80 years and central localization of the occlusion had independent negative prognostic effects on AFS. In the per-protocol population of 104 patients with unilateral ischemia, treatment per protocol, and successful revascularization, amputation or death within 4 weeks occurred in only 8% as compared with 33% in patients not fulfilling these criteria. No differences between treatment groups CT and CR were found, neither overall nor in the per-protocol population nor in patient subgroups defined by other pre- and intraoperative factors.

Conclusions—

Similar AFS in patients with CT or with CR was observed in this large randomized multicenter trial.

Clinical Trial Registration—

URL: http://www.drks.de . Unique identifier: DRKS00000579.

Endovascular intervention in Taiwanese patients with critical limb ischemia: patient outcomes in 333 consecutive limb procedures with a 3-year follow-up

BACKGROUND/PURPOSE

Midterm outcomes of endovascular intervention (EVI) for critical limb ischemia (CLI) have not been previously reported in Taiwan. This study assessed the safety, feasibility, and patient-oriented outcomes for CLI patients after EVI.

METHODS

From June 2005 to December 2011, 270 patients underwent EVI for CLI of 333 limbs. Primary patency (PP), assisted primary patency (AP), limb salvage, sustained clinical success (SCS), secondary SCS (SSCS), and survival were assessed using Kaplan-Meier analysis.

RESULTS

The procedural success rate was 89%, and the periprocedural mortality and major complication rates within 30 days were 0.6% and 6.9%, respectively. During the mean follow-up time of 27 ± 20 months (1-77), 64 patients died and 25 legs required major amputation. Eighty-one percent of the patients with tissue loss had wound healing at 6 months and 75% of the patients were ambulatory, with or without assisting devices, at 1 year. The overall survival and limb salvage rates at 3 years were 70% and 90%, respectively. The PP and AP at 1 and 3 years were 58% and 37% and 79% and 61%, respectively. The SCS and SSCS were 65% and 46% and 80% and 64% at 1 and 3 years, respectively.

CONCLUSION

In Taiwan, EVI was a safe and feasible procedure for CLI patients, with a high procedural success rate and lower complication rate. Sustained limb salvage and clinical success can be afforded with an active surveillance program and prompt intervention during midterm follow-up.

Procedural trends in the treatment of peripheral arterial disease by insurer status in New York State

BACKGROUND

Type or lack of insurance may affect access to care, treatment, and outcomes. We evaluated trends for surgical management of all peripheral arterial disease (PAD) in-hospital admissions by insurer status in New York State.

STUDY DESIGN

Statewide Planning and Research Cooperative System (SPARCS) data were obtained and cross-referenced for diagnostic and procedure codes. Data from 2001 to 2002 were averaged and used as a baseline. Change in indication, volume of admissions, procedures, and amputations were calculated for the years 2003 to 2008 and were analyzed by insurer status.

RESULTS

There were 83,949 admissions. Endovascular intervention (EVI) increased tremendously for all indications and was used equally in the insured and uninsured. Among critical limb ischemia admissions, patients with private insurance were significantly more likely to be admitted for rest pain and significantly less likely to be admitted for gangrene (p < 0.001). Admission for gangrene declined for all. As EVI increased, amputation decreased and was significantly lowest in patients with private insurance (p < 0.001). Amputation was significantly higher in Medicaid than other insured (Medicaid vs private, p < 0.001; Medicaid vs Medicare, p = 0.003), but comparable to the uninsured (p = 0.08). Age greater than 65 years and low socioeconomic class or minority status were significant risks for gangrene (p = 0.014; p < 0.001) and ultimate amputation (p = 0.05; p < 0.001). Lack of insurance may pose a similar risk.

CONCLUSIONS

EVI increased tremendously and was used without disparity across insurer status. Amputation declined steadily and may have been related to increased EVI or to decreased admission for gangrene. Advanced age, low socioeconomic class or minority status, and lack of insurance negatively affect presentation and limb salvage. Universal health care may be beneficial in improving outcomes but must address root causes for delayed presentation.

Prior contralateral amputation predicts worse outcomes for lower extremity bypasses performed in the intact limb

INTRODUCTION

To date, history of a contralateral amputation as a potential predictor of outcomes after lower extremity bypass (LEB) for critical limb ischemia (CLI) has not been studied. We sought to determine if a prior contralateral lower extremity amputation predicts worse outcomes in patients undergoing LEB in the remaining intact limb.

METHODS

A retrospective analysis of all patients undergoing infrainguinal LEB for CLI between 2003 and 2010 within hospitals comprising the Vascular Study Group of New England was performed. Patients were stratified according to whether or not they had previously undergone a contralateral major or minor amputation before LEB. Primary end points included major amputation and graft occlusion at 1 year postoperatively. Secondary end points included in-hospital major adverse events, discharge status, and mortality at 1 year.

RESULTS

Of 2636 LEB procedures, 228 (8.6%) were performed in the setting of a prior contralateral amputation. Patients with a prior amputation compared to those without were younger (66.5 vs 68.7; P = .034), more like to have congestive heart failure (CHF; 25% vs 16%; P = .002), hypertension (94% vs 85%; P = .015), renal insufficiency (26% vs 14%; P = .0002), and hemodialysis-dependent renal failure (14% vs 6%; P = .0002). They were also more likely to be nursing home residents (8.0% vs 3.6%; P = .036), less likely to ambulate without assistance (41% vs 80%; P < .0002), and more likely to have had a prior ipsilateral bypass (20% vs 12%; P = .0005). These patients experience increased in-hospital major adverse events, including myocardial infarction (MI; 8.9% vs 4.2%; P = .002), CHF (6.1% vs 3.4%; P = .044), deterioration in renal function (9.0% vs 4.7%; P = .006), and respiratory complications (4.2% vs 2.3%; P = .034). They were less likely to be discharged home (52% vs 72%; P < .0001) and less likely to be ambulatory on discharge (25% vs 55%; P < .0001). Although patients with a prior contralateral amputation experienced increased rates of graft occlusion (38% vs 17%; P < .0001) and major amputation (16% vs 7%; P < .0001) at 1 year, there was not a significant difference in mortality (16% vs 10%; P = .160). On multivariable analysis, prior contralateral amputation was an independent predictor of both major amputation (odds ratio, 1.73; confidence interval, 1.06-2.83; P = .027) and graft occlusion (odds ratio, 1.93; confidence interval, 1.39-2.68; P < .0001) at 1 year.

CONCLUSIONS

Patients with prior contralateral amputations who present with CLI in the intact limb represent a high-risk population, even among patients with advanced peripheral arterial disease. When considering LEB in this setting, both physicians and patients should expect increased rates of perioperative adverse events, increased rates of 1-year graft occlusion, and decreased rates of limb salvage, when compared with patients who have not undergone a contralateral amputation.

Chapter V: Diabetic foot

Ulcerated diabetic foot is a complex problem. Ischaemia, neuropathy and infection are the three pathological components that lead to diabetic foot complications, and they frequently occur together as an aetiologic triad. Neuropathy and ischaemia are the initiating factors, most often together as neuroischaemia, whereas infection is mostly a consequence. The role of peripheral arterial disease in diabetic foot has long been underestimated as typical ischaemic symptoms are less frequent in diabetics with ischaemia than in non-diabetics. Furthermore, the healing of a neuroischaemic ulcer is hampered by microvascular dysfunction. Therefore, the threshold for revascularising neuroischaemic ulcers should be lower than that for purely ischaemic ulcers. Previous guidelines have largely ignored these specific demands related to ulcerated neuroischaemic diabetic feet. Any diabetic foot ulcer should always be considered to have vascular impairment unless otherwise proven. Early referral, non-invasive vascular testing, imaging and intervention are crucial to improve diabetic foot ulcer healing and to prevent amputation. Timing is essential, as the window of opportunity to heal the ulcer and save the leg is easily missed. This chapter underlines the paucity of data on the best way to diagnose and treat these diabetic patients. Most of the studies dealing with neuroischaemic diabetic feet are not comparable in terms of patient populations, interventions or outcome. Therefore, there is an urgent need for a paradigm shift in diabetic foot care; that is, a new approach and classification of diabetics with vascular impairment in regard to clinical practice and research. A multidisciplinary approach needs to implemented systematically with a vascular surgeon as an integrated member. New strategies must be developed and implemented for diabetic foot patients with vascular impairment, to improve healing, to speed up healing rate and to avoid amputation, irrespective of the intervention technology chosen. Focused studies on the value of predictive tests, new treatment modalities as well as selective and targeted strategies are needed. As specific data on ulcerated neuroischaemic diabetic feet are scarce, recommendations are often of low grade.

Peripheral arterial disease in diabetic patients with renal insufficiency: a review

Peripheral arterial disease is common among diabetic patients with renal insufficiency, and most of the diabetic patients with end-stage renal disease (ESRD) have peripheral arterial disease. Ischaemia is probably overrepresented as an etiological factor for a diabetic foot ulcer in this group of patients compared with other diabetic patients. ESRD is a strong risk factor for both ulceration and amputation in diabetic patients. It increases the risk of nonhealing of ulcers and major amputation with an OR of 2.5-3. Renal disease is a more important predictor of poor outcome after revascularizations than commonly expected. Preoperative vascular imaging is also affected by a number of limitations, mostly related to side effects of contrast agents poorly eliminated because of kidney dysfunction. Patients with renal failure have high perioperative morbidity and mortality. Persistent ischaemia, extensive infection, forefoot and heel gangrene, poor run-off, poor cardiac function, and the length of dialysis-dependent renal failure all affect the outcome adversely. Despite dismal overall outcome, recent data indicate that by proper selection, favourable results can be obtained even in ESRD patients, with the majority of studies reporting 1-year limb salvage rates of 65-75% after revascularization among survivors. High 1-year mortality of 38% reported in a recent review has to be taken into consideration, though. The preferential use of endovascular-first approach is attractive in this vulnerable multimorbid group of patients, but the evidence for endovascular treatment is very scarce. The need for complete revascularization of the foot may be even more important than in other patients with ischaemic ulcerated diabetic foot because there are a number of factors counteracting healing in these patients. Typically, half of the patients are reported to lose their legs despite open bypass. To control tissue damage and improve chances of ulcer healing, one should understand that early referral to vascular consultation is necessary.

Developing and validating a risk score for lower-extremity amputation in patients hospitalized for a diabetic foot infection

OBJECTIVE

Diabetic foot infection is the predominant predisposing factor to nontraumatic lower-extremity amputation (LEA), but few studies have investigated which specific risk factors are most associated with LEA. We sought to develop and validate a risk score to aid in the early identification of patients hospitalized for diabetic foot infection who are at highest risk of LEA.

RESEARCH DESIGN AND METHODS

Using a large, clinical research database (CareFusion), we identified patients hospitalized at 97 hospitals in the U.S. between 2003 and 2007 for culture-documented diabetic foot infection. Candidate risk factors for LEA included demographic data, clinical presentation, chronic diseases, and recent previous hospitalization. We fit a logistic regression model using 75% of the population and converted the model coefficients to a numeric risk score. We then validated the score using the remaining 25% of patients.

RESULTS

Among 3,018 eligible patients, 21.4% underwent an LEA. The risk factors most highly associated with LEA (P < 0.0001) were surgical site infection, vasculopathy, previous LEA, and a white blood cell count >11,000 per mm(3). The model showed good discrimination (c-statistic 0.76) and excellent calibration (Hosmer-Lemeshow, P = 0.63). The risk score stratified patients into five groups, demonstrating a graded relation to LEA risk (P < 0.0001). The LEA rates (derivation and validation cohorts) were 0% for patients with a score of 0 and ~50% for those with a score of ≥21.

CONCLUSIONS

Using a large, hospitalized population, we developed and validated a risk score that seems to accurately stratify the risk of LEA among patients hospitalized for a diabetic foot infection. This score may help to identify high-risk patients upon admission.