Procedures For Peripheral Arterial Disease Research Articles

Outcomes of hybrid procedures for peripheral arterial disease: 5-year single center experience

Outcomes of hybrid procedures for peripheral arterial disease: 5-year single center experience

Open Surgical Therapy for Peripheral Artery Disease.

The surgical management of symptomatic peripheral artery disease (PAD) has changed in the last few decades. Improvement in endovascular technology has resulted in more complex lesion once reserved for open surgery being addressed in an endovascular fashion. Even with these advances, there are lesions and patients that are better managed with an open surgical procedure. The aim of this review is to describe the most commonly performed open surgical procedures for PAD. The recently published Best Endovascular versus Best Surgical Therapy (BEST-CLI) trial was an international, prospective, randomized controlled trial that aimed to investigate which revascularization (endovascular vs. surgical bypass) approach was superior for limb salvage. The evidence supports an open surgical bypass as an initial approach. The advancements made in the surgical management of PAD have provided options for patients who were once deemed poor surgical candidates. The goal continues to be utilization of the best available tools to address patient disease. In this current era, it is important to be familiar with the open surgical therapies.

HEALTH PRIORITIES ALIGNED DECISION MAKING FOR DISCRETE DECISIONS

Abstract The outcomes that establish the evidence-base and frame expectations for discrete interventions, primarily survival and disease-specific markers, may not be the outcomes older adults with multiple chronic conditions (MCCs) prioritize. An advisor group consisting of 6 health professionals with expertise in geriatrics, cardiology, vascular surgery and decision-making plus a panel of patient stakeholders created a decision-making framework titled ‘health priorities identification – discrete intervention decision’ (HPI-DID) process. This study aimed to refine the HPI-DID process using revascularization for peripheral arterial disease (PAD) as an exemplar procedure through eliciting feedback on the HPI-DID process from patients and caregivers. Seven older adults who recently underwent a revascularization procedure for PAD or their caregivers took part in one-to-one interviews with JB and SS. During interviews, participants were asked to verbalize or ‘think-aloud’ their thoughts while reviewing and performing each component of the health priorities process and probed what could be added or cut to improve the procedure-related communication and decision-making process. Participant feedback resulted in structural changes to the process. Font size was increased and specific words were bolded. Three additional tables detailing expected benefits, tradeoffs and complications from the procedure and their expected durations were added. The mean percentage of patients who experience these outcomes is now also listed. We will conduct a pilot trial to evaluate the feasibility and acceptability of our refined HPI-DID process with clinical interventionalists and older patients with MCCs considering revascularization for PAD.

External Validation of the OAC3-PAD Bleeding Score in a Nationwide Population of Patients Undergoing Invasive Treatment for Peripheral Arterial Disease

The OAC3-PAD score was developed to predict bleeding risk in patients with lower extremity peripheral arterial disease (PAD), but its performance in concomitant international cohorts is largely unknown. This study aimed to validate the OAC3-PAD score in an unselected nationwide population of patients undergoing invasive treatment for symptomatic PAD. This was a nationwide cohort study including all patients who underwent a first revascularisation procedure or major amputation for symptomatic PAD in Denmark from 2000 - 2021. The study population was stratified based on OAC3-PAD score, and the one year risk of major bleeding was assessed, accounting for the competing risk of death. The score performance was evaluated using calibration plots, C statistic, Brier score, and the index of prediction accuracy (IPA). A total of 52 016 patients were included (mean age 71 years, 43.8% female). The one year risk of major bleeding increased with higher OAC3-PAD score, ranging from 1.6% (95% confidence interval [CI] 1.4 - 1.8%) to 2.3% (95% CI 2.0 - 2.5%), 3.5% (95% CI 3.2 - 3.8%), and 5.2% (95% CI 4.8 - 5.6%) for patients with low, low moderate, moderate high, and high score, respectively. Using patients with low risk as reference, the OAC3-PAD score effectively categorised patients, demonstrating statistically significant differences in bleeding risk acrossstrata. However, the score showed modest discriminative performance, with a C statistic of 65% (95%CI 63 - 66%) and a Brier score of 2.6% (95% CI 2.5 - 2.7%). Nevertheless, it performed significantly better than the null model, as indicated by an IPA of 3.1%. Among patients who underwent invasive treatment for symptomatic PAD in routine care, the OAC3-PAD score was associated with greater risk of major bleeding with increasing score level. However, its discriminatory ability was modest, and the clinical utility remains to be determined.

The Additional Value of Activated Clotting Time-Guided Heparinization During Interventions for Peripheral Arterial Disease.

Unfractionated heparin is widely used to lower the risk of arterial thromboembolic complications (ATECs) during interventions for peripheral arterial disease (PAD), but it is still unknown which heparin dose is the safest in terms of preventing ATECs and bleeding complications. This study aims to evaluate the incidence of complications during interventions for PAD and the relation between this incidence and different heparinization protocols. A retrospective analysis of a prospective multicenter cohort study was performed. Between June 2015 and September 2022, 355 patients who underwent peripheral interventions for PAD were included. All patients who were included before July 2018 received 5000 international units (IU) of heparin (group 1). Starting from July 2018, all included patients received an initial dose of 100 IU/kg, with potential additional heparin doses based on activated clotting time (ACT) values (group 2). Data on ACT values and complications within 30 days post-procedurally were collected. In total, 24 ATECs and 48 bleeding complications occurred. In group 1, 8.7% (n=11) of patients suffered from ATEC, compared with 5.7% (n=13) in group 2. Thirteen percent of patients (n=17) in group 1 had a bleeding complication, compared with 14% (n=31) in group 2. Arterial thromboembolic complications were more often found in patients with peak ACT values of <200 seconds, compared with ACT values between 200 and 250 seconds, 15% (n=6) versus 5.9% (n=9), respectively, p=0.048. Patients with peak ACT values >250 seconds had a higher incidence of bleeding complications compared with an ACT between 200 and 250 seconds, 24% (n=21) versus 9.8% (n=15), respectively, p=0.003. Forty-four percent of patients (n=23) in group 1 reached a peak ACT of >200 seconds, compared with 95% (n=218) of patients in group 2 (p=0.001). ATEC was found in 6.8% (n=24) and bleeding complications in 14% (n=48) of patients who underwent a procedure for PAD. There was a significantly higher incidence of ATECs in patients with a peak ACT value <200 seconds, and a higher incidence of bleeding complications in patients with a peak ACT value >250 seconds. The findings obtained from this study may serve as a basis for conducting future research on heparinization during procedures for PAD, with a larger sample size. Heparin is administered during arterial interventions for peripheral arterial disease (PAD) to decrease the risk of arterial (thrombo)embolic complications (ATEC) during or shortly following surgery. The effect of heparin is unpredictable in the individual patient, and the optimal dosage of this anticoagulant has not yet been established. Using the activated clotting time (ACT), the anticoagulatory effect of heparin can be monitored periprocedurally. Previous research on the incidence of both ATEC and bleeding complications, or on the optimal dosage of heparin administration, is scarce. This study aims to investigate the incidence of ATEC and bleeding complications between 2 different dosage protocols of heparin-a standard bolus of 5000 IU or ACT-guided heparinization-and thereby provide clarity on the optimal dose of heparin during peripheral arterial interventions for PAD.

Analysis of Lower Extremity Amputations from the SerbVasc Registry.

Peripheral arterial disease (PAD) and diabetes are the major causes of lower extremity amputations (LEAs) worldwide. Morbidity and mortality in patients with LEAs are high with an associated significant burden on the global health system. The aim of this article is to report the overall morbidity and mortality rates after major and minor LEAs from the Serbian Vascular Registry (SerbVasc), with an analysis of predictive factors that influenced adverse outcomes. SerbVasc was created in 2019 as a part of the Vascunet collaboration that is aiming to include all vascular procedures from 21 hospitals in Serbia. Prevalence of diabetes among patients with LEAs, previous revascularization procedures, the degree and the type of foot infection and tissue loss, and overall morbidity and mortality rates were analyzed, with a special reference to mortality predictors. In the period from January 2020 to December 2022, data on 702 patients with LEAs were extracted from the SerbVasc registry, mean age of 69.06±10.63 years. Major LEAs were performed in 59%, while minor LEAs in 41% of patients. Diabetes was seen in 65.1% of the patients, with 44% of them being on insulin therapy. Before LEA, only 20.3% of patients had previous peripheral revascularization. Soft tissue infection, irreversible acute ischemia, and Fontaine III and IV grade ischemia were the most common causes of above-the-knee amputations while diabetic foot was the most common cause of transphalangeal and toe amputations. The infection rate was 3.7%, the re-amputation rate was 5.7%, and the overall mortality rate was 6.9%, with intrahospital mortality in patients with above-the-knee amputation of 11.1%. The most significant intrahospital mortality predictors were age >65 years (p<0.001), chronic kidney disease (CKD) (p<0.001), ischemic heart disease (IHD) (p=0.001), previous myocardial revascularization (p=0.017), emergency type of admission (p<0.001), not using aspirin (p=0.041), using previous anticoagulation therapy (p=0.003), and postoperative complications (p<0.001). The main predictors of increased mortality after LEAs from the SerbVasc registry are age >65 years, CKD, IHD, previous myocardial revascularization, emergency type of admission, not using aspirin, using previous anticoagulation therapy, and postoperative complications. Taking into account high mortality rates after LEAs and a small proportion of previous peripheral revascularization, the work should be done on early diagnosis and timely treatment of PAD hopefully leading to decreased number of LEAs and overall mortality. Mortality after lower limb amputation from the SerbVasc register is high. A small number of previously revascularized patients is of particular clinical importance, bearing in mind that the main reasons for above-the-knee amputations were irreversible ischemia, Fontaine III and Fontaine IV grade ischemia. Lack of diagnostics procedures and late recognition of patients with PAD, led to subsequent threating limb ischemia and increased amputation rates. The work should be done on early diagnosis and timely treatment of PAD in Serbia, hopefully leading to an increased number of PAD procedures, decreased number of LEAs, and lower overall mortality.

Intravascular Ultrasound Guidance During Peripheral Vascular Interventions: Long-term Clinical Outcomes and Costs From the Japanese Perspective.

The value of intravascular ultrasound (IVUS) guidance during peripheral vascular revascularization procedures is incompletely understood. Moreover, data on long-term clinical outcomes and costs are limited. The objective of this study was to compare outcomes and costs between IVUS and contrast angiography alone in patients undergoing peripheral revascularization procedures in Japan. This retrospective comparative analysis was performed using the Japanese Medical Data Vision insurance claims database. All patients undergoing revascularization for peripheral artery disease (PAD) between April 2009 and July 2019 were included. Patients were followed until July 2020, death, or a subsequent revascularization procedure for PAD. Two patient groups were compared: one undergoing IVUS imaging or the other contrast angiography alone. The primary end point was major adverse cardiac and limb events, including all-cause-mortality, endovascular thrombolysis, subsequent revascularization procedures for PAD, stroke, acute myocardial infarction, and major amputations. Total health care costs were documented over the follow-up and compared between groups, using a bootstrap method. The study included 3956 patients in the IVUS group and 5889 in the angiography alone group. Intravascular ultrasound was significantly associated with reduced risk of a subsequent revascularization procedure (adjusted hazard ratio: 0.25 [0.22-0.28]) and major adverse cardiac and limb events (0.69 [0.65-0.73]). The total costs were significantly lower in the IVUS group, with a mean cost saving over follow-up of $18 173 [$7 695-$28 595] per patient. The use of IVUS during peripheral revascularization provides superior long-term clinical outcomes at lower costs compared with contrast angiography alone, warranting wider adoption and fewer barriers to IVUS reimbursement for patients with PAD undergoing routine revascularization. Intravascular ultrasound (IVUS) guidance during peripheral vascular revascularization has been introduced to improve the precision of the procedure. However, questions over the benefit of IVUS in terms of long-term clinical outcome and over cost have limited its use in everyday clinical practice. This study, performed in a Japanese health insurance claims database, demonstrates that use of IVUS provides a superior clinical outcome over the long term at a lower cost compared to angiography alone. These findings should encourage clinicians to use IVUS in routine peripheral vascular revascularization procedures and encourage providers to reduce barriers to use.

PCR106 Comparing Maximum-Acceptable Risk Estimates from 2 Preference-Elicitation Methods: A Discrete-Choice Experiment and a Threshold-Technique Exercise

A stated-preference study aimed to quantify patients’ benefit-risk preferences for alternative devices used in revascularization procedures for peripheral arterial disease (PAD). A main objective was testing whether parallel discrete-choice experiment (DCE) and threshold-technique (TT) data would yield similar maximum acceptable risk (MAR) estimates.

An interpretable machine learning model for the prevention of contrast-induced nephropathy in patients undergoing lower extremity endovascular interventions for peripheral arterial disease

BackgroundContrast-induced nephropathy (CIN) is a postprocedural complication associated with increased morbidity and mortality. An important risk factor for development of CIN is renal impairment. Identification of patients at risk for acute renal failure will allow physicians to make appropriate decisions to minimize the incidence of CIN. We developed a machine learning model to stratify risk of acute renal failure that may assist in mitigating risk for CIN in patients with peripheral artery disease (PAD) undergoing endovascular interventions. MethodsWe utilized the American College of Surgeons National Surgical Quality Improvement Program database to extract clinical and laboratory information associated with 14,444 patients who underwent lower extremity endovascular procedures between 2011 and 2018. Using 11,604 cases from 2011 to 2017 for training and 2840 cases from 2018 for testing, we developed a random forest model to predict risk of 30-day acute renal failure following infra-inguinal endovascular procedures. ResultsEight variables were identified as contributing optimally to model predictions, the most important being diabetes, preoperative BUN, and claudication. Using these variables, the model achieved an area under the receiver-operating characteristic (AU-ROC) curve of 0.81, accuracy of 0.83, sensitivity of 0.67, and specificity of 0.74. The model performed equally well on white and nonwhite patients (Delong p-value = 0.955) and patients age < 65 and patients age ≥ 65 (Delong p-value = 0.659). ConclusionsWe develop a model that fairly and accurately stratifies 30-day acute renal failure risk in patients undergoing lower extremity endovascular procedures for PAD. This model may assist in identifying patients who may benefit from strategies to prevent CIN.

Endovascular interventions in outpatient care

Endovascular arterial revascularisations for the treatment of symptomatic peripheral arterial disease are constantly increasing in importance and number due to the changing age structure and high numbers of comorbidities in the German population. Patients with peripheral artery disease are often at increased risk for peri- and post-procedural complications including severe cardiovascular events. Due to limited financial and human resources and considerable risks of hospitalization, endovascular interventions that were previously reserved for hospitalized patients are now progressively considered to be performed as day case procedures. More than one third of these procedures are performed in Germany by internists with a specialization in angiology. In the current position paper the German Society of Angiology endorsed by the European Society of Vascular Medicine, summarizes the requirements and risk factors to be considered for the planning, safe performance and post procedural care of endovascular revascularizations in outpatients. The performance of endovascular procedures for peripheral artery disease both in hospitalised and outpatients should be accompanied by a mandatory quality assurance process that should not only capture procedural data, but also require documentation of complications and longterm outcome.

Outcomes of hybrid procedures for peripheral arterial disease: 5-year single center experience.

The objective of the study was to present patients with peripheral vascular disease (PVD) who underwent hybrid procedures at our institution, the results of these interventions for a 5-year period and determine patency, mortality, failure, and amputation rates compared to the literature. Observational, single center, retrospective, and cross-sectional study which analyzed data gathered from the vascular quality initiative from patients who had hybrid revascularization procedures from January 2010 to December 2015. 87 patients were identified: 51 (58%) male, 36 (41%) female, 9 (10%) had critical limb ischemia (CLI), and 78 (90%) claudication. We analyzed results of hybrid interventions in their variations. Technical success rate was 100%, patency at 2 years 88.5% (primary 65%, primary-assisted 18.3%, and secondary 4.5%) and 11.49% failure rate (lost patency < 1 year, conversion to open or/and amputation). Predictors of failure were: Female, previous chronic heart failure, longer length of stay, and previously transferred from another hospital. Amputation rate was 12.6% (10.3% major and 2.2% minor amputation), the only significant predictor was age (p = 0.035, odds ratio = 0.89) (0.806-99). Hybrid procedures are effective to treat patients with either CLI or claudication. Our study had outcomes comparable to the literature, with similar patency, amputation, and complication rates. We conclude it is a safe and effective option for PVD with multi-level disease.

Impact of socioeconomic disparities on major lower extremity revascularization complications.

Low socioeconomic status (SES), distance lived from hospital, and insurance status are well documented in the literature to increase the risk of post-operative morbidity and mortality for some disease processes however there is a paucity of data regarding how this association impacts patients with peripheral artery disease (PAD). This study aimed to evaluate if SES, distance lived from hospital, and insurance status increased the risk of developing major graft failure in patients undergoing revascularization procedures for symptomatic PAD in a prospective, observation study. In this prospective, observational study, all patients undergoing lower extremity revascularization (endovascular or open) were included from December 2020 to February 2022. Demographic factors, insurance status, operative details, and median income and distance from hospital were documented through chart review. Complications were defined as thrombosis/occlusion of the revascularized vessel or bypass graft or infection of the distal wound or surgical incision wound. Univariate and multivariate analysis were performed comparing patients that developed complications and those that did not. This project was undertaken at the Massachusetts General Hospital and was governed by the Institutional Review Board (IRB: 2020P000263) all patients agreed to participation via informed written consent prior to enrollment in the study. A total of 108 patients were enrolled in the study of which 94 underwent successful revascularization procedures. Of those 94 patients, 38 (40.4%) underwent open bypass, 39 (41.5%) underwent endovascular revascularization, and 17 (18.1%) underwent a hybrid approach. There were no significant differences in post-operative outcomes between operative approaches. Twenty-five patients (28.7%) experienced major revascularization complications as defined as re-occlusion of the treated vessel/thrombosis of the bypass graft (n = 13) or development of post-operative infection (n = 12). There was no significant difference in median income ($75,295 vs $87,757, p = NS), distance lived from hospital, (27.4 miles vs. 29.7 miles, p = NS), or type of insurance (private 24% vs 26%, government 76% vs 73%, p = NS between patients that experienced complications versus those that did not have complications. These findings suggest the risk of major graft failure is independent of a patient's socioeconomic status, distance lived from hospital, or insurance type in patients undergoing revascularization procedures for PAD. While socioeconomic factors impact access to and have a known association with negative outcomes, complications in patients with PAD appear to be independent of these factors. To mitigate the negative outcomes in patients with peripheral artery disease, a focus should be on patient risk factors and modifiable medical factors that contribute to adverse outcomes.

Risk Factors Associated 90-Day Readmission among Patients with Peripheral Artery Disease Undergoing Revascularization Procedures

Introduction: The CMS Bundled Payments for Care Improvement-Advanced program provides a single payment for all anticipated care within 90-days of surgery. Readmission are an important driver of healthcare cost, however, factors associated with 90-day readmission after peripheral artery disease (PAD) intervention are not well-described. Methods: National cohort of adults over 65 in the Vascular Quality Initiative-CMS linked dataset who underwent open, endovascular, or hybrid procedures for PAD between 2010 and 2018. The primary outcome was 90-day readmission. Multivariable Cox regression analysis was used to evaluate associations between patient- and facility-level characteristics and 90-day readmission. Results: 42,429 patients over age 65 underwent revascularization for PAD during the study period. The median age was 74(69-80), 58.9% were male and 84.3% were White. Over two-thirds of revascularizations were performed via endovascular method and over half had revascularization for chronic limb threatening ischemia (CLTI). The 90-day readmission rate was 30.9%. Patient-level factors such as advanced age, CLTI upon presentation, poor functional status, and most comorbidities of interest were associated with higher 90-day readmission. Those who had an outpatient index revascularization were less likely to have subsequent readmission (ref - inpatient; outpatient [HR 0.60 (95% CI 0.56-0.64)]; office-based lab [HR 0.61 (95% CI 0.51-0.72)]). Conclusion: Patient (e.g., age, comorbidity, severity of PAD upon presentation) and facility (e.g., site of index procedure) characteristics are associated with increased risk for 90-day readmission in PAD patients undergoing revascularization. This data may be used to guide novel intervention that will improve this quality metric among patients undergoing PAD intervention.

Risk Factor Analysis and Long-Term Outcomes in Patients with Endovascular Revascularization for Intermittent Claudication or Chronic Limb-Threatening Ischemia

The aim of this study is to review long-term outcome and identify risk factors for patients with peripheral arterial disease (PAD) with percutaneous transluminal angioplasty/stent as a primary treatment strategy for intermittent claudication (IC) or chronic limb-threatening ischemia (CLTI). A retrospective cohort study with data collected prospectively from Clinical Data Analysis and Reporting System, departmental database, and Clinical Management System. All patients who underwent endovascular procedures for PAD between January 2011 and December 2020 were identified. The primary outcomes are overall survival and amputation-free survival. Predictive factors for OS and AFS were determined using Cox Model. A total number of 640 patients with PAD (IC, n=243; CLTI, n=377) underwent endovascular percutaneous transluminal angioplasty/stenting for PAD from January 2011 to December 2020. Patients with CLTI had a significantly higher 30days readmission rate (18.8% vs. 6.5%, P<0.001), emergency reoperation within 30days (3.4% vs. 0%, P=0.002), and death within same admission (2.7% vs. 0%, P=0.008) compared to IC patients. The overall survival and amputation-free survival rates were significantly lower in CLTI patients (P<0.0001 and P<0.0001, respectively). On Cox multivariate analysis, CLTI was strongly predictive of all-cause mortality and amputation (hazard ratio [HR] 2.33 and HR 14.92, respectively). In patients with CLTI, chronic kidney disease was an independent predictor of mortality and amputation (HR 1.66 and HR 2.36, respectively). Smoking and ischemic heart disease were also independent predictors of mortality in this subgroup (HR 2.06 and HR 2.43, respectively). Although patients with IC and CLTI both manifest from atherosclerotic occlusive disease of the lower limb arteries, these patients may have different clinical outcomes with significant mortality occurred in both IC and CLTI groups. In patients with IC, the risk of amputation was less than 1% at 5years following revascularization.

Reintervention Following Outpatient Peripheral Artery Disease Procedures: Trading Convenience for Value?

Peripheral artery disease (PAD) represents a high volume, high-cost burden on the healthcare system. The Centers for Medicare and Medicaid Services has developed the Bundled Payments for Care Improvement-Advanced program, in which a single payment is provided for all services to be administered in a postsurgical 90-day episode of care. Factors associated with 30- and 90-day reinterventions after PAD interventions would represent useful data for both payors and stake holders. We conducted a national cohort study of adults 65 years and older in the Vascular Quality Initiative and Centers for Medicare and Medicaid Services linked dataset who underwent an open, endovascular, or hybrid revascularization procedure for PAD between January 1, 2010, and December 31, 2018. Procedures for acute limb ischemia and aneurysm indications were excluded. The primary outcome was 90-day reintervention and 30-day reintervention was a secondary outcome. Covariates of interest included demographic, comorbidities, and patient and facility level characteristics. Multivariable Cox regression was used to determine the association between patient- and facility-level characteristics and the risk of 30- and 90-day reinterventions. Among 42,429 patients (71.3% endovascular, 23.3% open, and 5.4% hybrid), median (interquartile range) age was 74 years (interquartile range, 69-80 years), 58.9% were male, and 84.3% were White. Chronic limb-threatening ischemia was the operative indication in 56.4%; 42.8% of the procedures were completed in the outpatient setting (40.3% outpatient, 2.5% office-based laboratory). More than 70% of procedures for chronic limb-threatening ischemia were completed as an inpatient, while 60% of the claudication interventions were done as an outpatient. The 30-day reintervention rate was 5.5% and the 90-day reintervention rate was 14.5%. Compared with inpatient procedures, PAD interventions completed in the outpatient or office-based laboratory setting had significantly higher 30- and 90-day reintervention rates (ref, inpatient; outpatient 30-day reintervention: hazard ratio [HR], 1.90; 95% confidence interval [CI], 1.62-2.24]; outpatient 90-day reintervention: HR, 1.41; 95% CI, 1.25-1.60); office-based laboratory 30-day reintervention: HR, 3.54; 95% CI, 3.17-3.94]; office-based laboratory 90-day reintervention, HR, 2.09; 95% CI, 1.82-2.41) Open and hybrid approaches demonstrated lower risk of reintervention compared with endovascular procedures at 30 and 90 days and, compared with aortoiliac disease, all other anatomic segments of disease were associated with higher 90-day reintervention but no difference was noted at 30 days (Table). Although outpatient PAD interventions may be convenient for patients and providers, the outpatient setting is associated with a significant risk of subsequent 30- and 90-day reintervention. Additional work is needed to understand how to improve the longevity of outpatient PAD interventions.TableMultivariable analysis of factors associated with 30- and 90-day reinterventionsCovariate30-Day reintervention90-Day reinterventionAdjusted hazard ratio95% confidence intervalAdjusted hazard ratio95% confidence intervalStandard demographics Age 70-74 vs 65-690.950.891.020.990.951.04 Age 75-79 vs 65-690.950.841.090.950.881.03 Age 80-84 vs 65-691.000.841.190.950.861.05 Age ≥85 vs 65-690.990.911.080.880.820.94 Female vs male0.760.690.830.870.820.92 Non-White vs White1.050.931.191.050.971.14Comorbidities BMI ≥30 vs BMI <300.950.871.030.930.890.98 Coronary artery disease0.990.881.121.101.041.15 Congestive heart failure0.990.891.090.940.890.99 Chronic obstructive pulmonary disease1.040.971.131.081.011.16 Diabetes mellitus1.030.941.141.050.991.10 ESRD on dialysis1.461.311.631.381.261.50 Hypertension1.070.931.241.090.981.22 Microvascular disease1.010.901.141.010.921.11 Current smoker vs nonsmoker1.130.991.300.980.911.06 Prior smoker vs nonsmoker1.080.971.201.010.941.08Patient-level characteristics Ischemic rest pain vs claudication1.171.011.361.101.001.20 Tissue loss vs claudication1.110.991.241.070.991.15 Femoropopliteal vs aortoiliac1.050.911.211.241.151.35 Tibial vs aortoiliac0.930.771.111.311.191.45 Aortoiliac + any outflow vs aortoiliac1.140.961.351.381.251.51 Femoropopliteal + tibial vs aortoiliac1.030.821.301.341.171.54 Prior LER0.930.851.020.990.941.04 Ambulation with assistance vs ambulatory1.121.011.241.080.981.18 Wheelchair/bedridden vs ambulatory0.880.731.060.870.790.96 Homeless vs home0.000.000.000.430.111.67 Nursing home vs home0.880.681.140.820.730.91Facility-level or operative characteristics Office/clinic vs inpatient3.543.173.942.091.822.41 Outpatient vs inpatient1.901.612.241.411.251.60 Hybrid vs endovascular0.440.340.580.740.650.85 Open vs endovascular0.460.380.560.780.690.89 Year of procedure 2013-2015 vs 2010-20121.020.781.321.120.981.27 Year of procedure 2016-2018 vs 2010-20120.930.671.291.040.901.20 Distance to care 5-10 miles vs <5 miles1.030.941.131.020.951.11 Distance to care >10-20 miles vs <5 miles1.000.881.140.980.901.07 Distance to care >20-40 miles vs <5 miles1.070.921.251.040.941.15 Distance to care >40-60 miles vs <5 miles1.070.911.271.050.941.18 Distance to care >60 miles vs <5 miles0.860.661.120.960.841.11BMI, body mass index; LER, lower extremity revascularization; ESRD, end stage renal disease.All variables in the table are included in the model. 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Stretched reconstruction based on 2D freehand ultrasound for peripheral artery imaging

Endovascular revascularization is becoming the established first-line treatment of peripheral artery disease (PAD). Ultrasound (US) imaging is used pre-operatively to make the first diagnosis and is often followed by a CT angiography (CTA). US provides a non-invasive and non-ionizing method for the visualization of arteries and lesion(s). This paper proposes to generate a 3D stretched reconstruction of the femoral artery from a sequence of 2D US B-mode frames. The proposed method is solely image-based. A Mask-RCNN is used to segment the femoral artery on the 2D US frames. In-plane registration is achieved by aligning the artery segmentation masks. Subsequently, a convolutional neural network (CNN) predicts the out-of-plane translation. After processing all input frames and re-sampling the volume according to the vessel's centerline, the whole femoral artery can be visualized on a single slice of the resulting stretched view. 111 tracked US sequences of the left or right femoral arteries have been acquired on 18 healthy volunteers. fivefold cross-validation was used to validate our method and achieve an absolute mean error of 0.28 ± 0.28mm and a median drift error of 8.98%. This study demonstrates the feasibility of freehand US stretched reconstruction following a deep learning strategy for imaging the femoral artery. Stretched views are generated and can give rich diagnosis information in the pre-operative planning of PAD procedures. This visualization could replace traditional 3D imaging in the pre-operative planning process, and during the pre-operative diagnosis phase, to identify, locate, and size stenosis/thrombosis lesions.

Interpretable Machine Learning for the Prediction of Amputation Risk Following Lower Extremity Infrainguinal Endovascular Interventions for Peripheral Arterial Disease.

Severe peripheral artery disease (PAD) may result in lower extremity amputation or require multiple procedures to achieve limb salvage. Current prediction models for major amputation risk have had limited performance at the individual level. We developed an interpretable machine learning model that will allow clinicians to identify patients at risk of amputation and optimize treatment decisions for PAD patients. We utilized the American College of Surgeons National Surgical Quality Improvement Program database to collect preoperative clinical and laboratory information on 14,444 patients who underwent lower extremity endovascular procedures for PAD from 2011 to 2018. Using data from 2011 to 2017 for training and data from 2018 for testing, we developed a machine learning model to predict 30day amputation in this patient population. We present performance metrics overall and stratified by race, sex, and age. We also demonstrate model interpretability using Gini importance and SHapley Additive exPlanations. A random forest machine learning model achieved an area under the receiver-operator curve (AU-ROC) of 0.81. The most important features of the model were elective surgery designation, claudication, open wound/wound infection, white blood cell count, and albumin. The model performed equally well on white and non-white patients (Delong p-value = 0.189), males and females (Delong p-value = 0.572), and patients under age 65 and patients age 65 and older (Delong p-value = 0.704). We present a machine learning model that predicts 30day major amputation events in PAD patients undergoing lower extremity endovascular procedures. This model can optimize clinical decision-making for patients with PAD.

Disparities in Advanced Peripheral Arterial Disease Presentation by Socioeconomic Status

BackgroundDiabetes and peripheral arterial disease (PAD) often synergistically lead to foot ulceration, infection, and gangrene, which may require lower limb amputation. Worldwide there are disparities in the rates of advanced presentation of PAD for vulnerable populations. This study examined rates of advanced presentations of PAD for unemployed patients, those residing in low Index of Economic Resources (IER) areas, and those in rural areas of Australia.MethodsA retrospective study was conducted at a regional tertiary care centre (2008–2018). To capture advanced presentations of PAD, the proportion of operative patients presenting with complications (gangrene/ulcers), the proportion of surgeries that are amputations, and the rate of emergency to elective surgeries were examined. Multivariable logistic regression adjusting for year, age, sex, Charlson Comorbidity Index, and sociodemographic variables was performed.ResultsIn the period examined, 1115 patients underwent a surgical procedure for PAD. Forty-nine per cent of patients had diabetes. Following multivariable testing, the rates of those requiring amputations were higher for unemployed (OR 1.99(1.05–3.79), p = 0.036) and rural patients (OR 1.83(1.21–2.76), p = 0.004). The rate of presentation with complications was higher for unemployed (OR 7.2(2.13–24.3), p = 0.001), disadvantaged IER (OR 1.91(1.2–3.04), p = 0.007), and rural patients (OR 1.73(1.13–2.65), p = 0.012). The rate of emergency to elective surgery was higher for unemployed (OR 2.32(1.18–4.54), p = 0.015) and rural patients (OR 1.92(1.29–2.86), p = 0.001).ConclusionsThis study found disparities in metrics capturing delayed presentations of PAD: higher rates of presentations with complications, higher amputation rates, and increased rates of emergency to elective surgery, for patients of low socioeconomic status and those residing in rural areas. This suggests barriers to appropriate, effective, and timely care exists for these patients.

Preoperative HbA1c and Outcomes following Lower Extremity Vascular Procedures

BackgroundLimited data exist evaluating preoperative hemoglobin A1c (HbA1c) in patients undergoing vascular procedures for peripheral arterial disease (PAD). This study evaluated the relationship of preoperative HbA1c on outcomes after open and endovascular lower extremity (LE) vascular procedures for PAD. MethodsWe selected patients with PAD admitted for elective LE procedures between September 2008 and December 2015 from the Cerner Health Facts® database using International Classification of Disease, Ninth Edition, Clinical Modification diagnosis and procedure codes. Bivariable analysis and multivariable logistic models examined the association of patient characteristics, procedure type, and preoperative HbA1c (normal < 6.5%, high ≥ 6.5%) with postsurgical outcomes that included infection, renal failure, respiratory or cardiac complications, length of stay, in-hospital mortality, and readmission. ResultsOf 4087 patients who underwent a LE vascular procedure for PAD, 2462 (60.2%) had a preoperative HbA1c recorded. The cohort was mostly male (60%), white (73%), and underwent endovascular intervention (77%). Patients with high HbA1c levels were more likely of black race (P < 0.02) and had significantly higher comorbidities (P < 0.0001). Elevated HbA1c was associated with diabetes (P < 0.0001) and cellulitis (P = 0.05) on unadjusted analysis. Multivariable logistic regression (adjusting for patient, hospital, comorbidity and procedural characteristics) revealed that elevated HbA1c was significantly associated with 30-day readmission (OR = 1.06, 95% confidence interval = 1.00–1.12), but was not associated with the other outcomes. An independent diagnosis of diabetes was not predictive of complications or readmission. ConclusionsHistoric glucose control, as evidenced by a high preoperative HbA1c level, is not associated with adverse outcome, other than readmission, in patients undergoing LE procedures for PAD. Given the known association of high perioperative glucose levels with poor outcome following vascular procedures, this is suggestive of a more important effect of perioperative, as opposed to chronic, glucose control upon outcome. Thus, we suggest focusing efforts on creating standardized goal-directed guidelines for glucose control in the perioperative period for LE vascular procedures to potentially mitigate complications.

Update on Cilostazol: A Critical Review of Its Antithrombotic and Cardiovascular Actions and Its Clinical Applications.

Cilostazol, a phosphodiesterase III inhibitor, has vasodilating and antiplatelet properties with a low rate of bleeding complications. It has been used over the past 25 years for improving intermittent claudication in patients with peripheral artery disease (PAD). Cilostazol also has demonstrated efficacy in patients undergoing percutaneous revascularization procedures for both PAD and coronary artery disease. In addition to its antithrombotic and vasodilating actions, cilostazol also inhibits vascular smooth muscle cell proliferation via phosphodiesterase III inhibition, thus mitigating restenosis. Accumulated evidence has shown that cilostazol, due to its "pleiotropic" effects, is a useful, albeit underutilized, agent for both coronary artery disease and PAD. It is also potentially useful after ischemic stroke and is an alternative in those who are allergic or intolerant to classical antithrombotic agents (eg, aspirin or clopidogrel). These issues are herein reviewed together with the pharmacology and pharmacodynamics of cilostazol. Large studies and meta-analyses are presented and evaluated. Current guidelines are also discussed, and the spectrum of cilostazol's actions and therapeutic applications are illustrated.