Longitudinal Changes in Iron and Myelination Within Ischemic Lesions Associate With Neurological Outcomes: A Pilot Study.

BACKGROUND: Combined quantitative susceptibility mapping and R2* relaxometry can distinguish iron and myelin components in ischemic lesions. We aimed to investigate whether longitudinal changes in magnetic susceptibility and R2* values within ischemic lesions were associated with neurological outcomes. METHODS: In this single-center prospective study, we included patients, 20 to 90 years of age, who were consecutively admitted to the stroke care unit between August 2020 and March 2022 due to acute ischemic stroke. The participants underwent 2 instances of quantitative susceptibility mapping and R2* relaxometry scanning before and after stroke rehabilitation. We compared the changes in these quantitative measures across different subtypes of acute ischemic stroke. Multiple linear regression models were used to investigate the associations between the National Institutes of Health Stroke Scale scores and the mean magnetic susceptibility and R2* values in ischemic lesions. RESULTS: Among a total of 112 patients with acute ischemic stroke, 32 participants (aged 73.3±9.4 years; 20 men and 12 women) were evaluated. The median time from stroke onset to the first imaging was 5 days and that to the second imaging was 102 days. The changes in magnetic susceptibility values of branch atheromatous disease were higher than those of cardioembolism (mean difference, 0.018 [95% CI, 0.009-0.027] ppm; P<0.001) and lacunar (mean difference, 0.013 [95% CI, 0.005-0.020] ppm; P=0.004). Across all patients, the changes in National Institutes of Health Stroke Scale scores were associated with those of magnetic susceptibility values (coefficient, 0.311 [95% CI, 0.098-0.520]; P=0.017) but not with R2* values (coefficient, 0.114 [95% CI, -0.127 to 0.345]; P=0.291). CONCLUSIONS: The longitudinal changes in the magnetic susceptibility values within ischemic lesions were associated with neurological outcomes during the restorative stages poststroke in patients experiencing acute ischemic stroke. REGISTRATION: URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000050719.

Specific and rapid guanidinium CEST imaging using double saturation power and QUASS analysis in a rodent model of global ischemia.

PURPOSE: Guanidinium CEST is sensitive to metabolic changes and pH variation in ischemia, and it can offer advantages over conventional pH-sensitive amide proton transfer (APT) imaging by providing hyperintense contrast in stroke lesions. However, quantifying guanidinium CEST is challenging due to multiple overlapping components and a close frequency offset from water. This study aims to evaluate the applicability of a new rapid and model-free CEST quantification method using double saturation power, termed DSP-CEST, for isolating the guanidinium CEST effect from confounding factors in ischemia. To further reduce acquisition time, the DSP-CEST was combined with a quasi-steady state (QUASS) CEST technique to process non-steady-state CEST signals. METHODS: The specificity and accuracy of the DSP-CEST method in quantifying the guanidinium CEST effect were assessed by comparing simulated CEST signals with/without the contribution from confounding factors. The feasibility of this method for quantifying guanidinium CEST was evaluated in a rat model of global ischemia induced by cardiac arrest and compared to a conventional multiple-pool Lorentzian fit method. RESULTS: The DSP-CEST method was successful in removing all confounding components and quantifying the guanidinium CEST signal increase in ischemia. This suggests that the DSP-CEST has the potential to provide hyperintense contrast in stroke lesions. Additionally, the DSP-CEST was shown to be a rapid method that does not require the acquisition of the entire or a portion of the CEST Z-spectrum that is required in conventional model-based fitting approaches. CONCLUSION: This study highlights the potential of DSP-CEST as a valuable tool for rapid and specific detection of viable tissues.

Impact of wound management strategies after revascularization for chronic limb-threatening ischemia.

OBJECTIVE: There is no established consensus or guidelines for wound management after revascularization for patients with chronic limb-threatening ischemia (CLTI) without severe infection. This study is designed to evaluate the clinical effect of the wound management strategy on toe wounds after revascularization for CLTI. METHODS: This retrospective cohort study was performed at eight institutions affiliated with Keio University School of Medicine in Japan and included 261 patients who underwent revascularization for CLTI between April 2019 and July 2021. We identified 132 patients with toe wounds from the database who had restored in-line blood flow to the foot. Patients were divided into two groups by the timing of toe resection after revascularization, which dictated the wound management policy. Group A (62 patients) underwent early toe amputation for suspected osteomyelitis, whereas group B (70 patients) underwent watchful waiting. The primary outcome was wound healing after revascularization; the secondary outcome was major amputation. We compared outcomes between groups A and B after propensity score matching. RESULTS: Using propensity score matching, each patient in group A (33 patients) was matched with a patient in group B (33 patients). Wound healing in matched group A was significantly better than that in matched group B (respectively: 1-year wound healing rate: 90.0% vs 68.2%, P < .001; median wound healing time: 65 days vs 258 days, P < .01). Although five major amputations were necessary in matched group B, none were required in matched group A (P = .05). The high rate of major amputations in group B was attributed to the sudden exacerbation of infection. Limb salvage rate in matched group A exceeded matched group B (100.0% vs 90.5%: 1-year limb salvage rate, P = .02). CONCLUSIONS: Early toe amputation for highly suspected osteomyelitis in patients with CLTI with toe wounds may expedite wound healing compared with watchful waiting, potentially avoiding unnecessary major amputation. Considering the wound management strategy is crucial when evaluating wound healing outcomes in patients with CLTI with revascularization.

Long-term value in open and endovascular repair of chronic mesenteric ischemia.

OBJECTIVE: Guidelines recommend open revascularization (OR) over endovascular revascularization (ER) for the treatment of chronic mesenteric ischemia (CMI) for younger, healthier patients. However, little is known about the long-term costs of these recommendations with respect to patients' overall life expectancy. This study investigated whether 5-year value differs between these treatment modalities. METHODS: Patient data were extracted from the Statewide Planning and Research Cooperative System, the New York statewide all-payor database containing demographics, diagnoses, treatments, and charges. The database was queried for patients with an International Classification of Diseases, ninth revision, code for CMI, with the specific exclusion of acute ischemia cases. A propensity score match was performed using the Charlson Comorbidity Index, age, sex, race, renal status, and pulmonary disease for the final cohort of patients. Multiple linear regression and mixed effects linear regression were used to determine factors associated with 5-year value, calculated as life-years/$100k in charges. Charges were gathered from the index admission and subsequent admissions for acute or CMI, mesenteric angiography, or follow-up reintervention. Kaplan-Meier estimation was performed for survival and reintervention-free survival. RESULTS: From 2000 to 2014, 875 patients underwent intervention for CMI. Of those meeting inclusion criteria, 209 (28.1%) underwent OR and 535 (71.9%) ER. After propensity score matching (n = 209 in each group), the ER group showed higher value at 5 years after the procedure (8.04 ± 11.42 life-years/$100k charges vs 4.89 ± 5.28 life-years/$100k charges; P < .01). More patients underwent reintervention in the ER group (37 patients vs 17 patients; P < .01), with 55 reinterventions in the ER group and 19 in the OR group (P < .01). Multiple linear regression analysis showed that age, congestive heart failure, dysrhythmia, cancer, and days spent in the intensive care unit were negatively associated with value at 5 years, whereas ER was positively associated. Survival was 59.6 ± 3.76% vs 62.3% ± 3.49% at 5 years (P = .91), and reintervention-free survival was 43.7 ± 3.86% vs 58.1 ± 3.53% (P = .04), for ER and OR respectively. CONCLUSIONS: Despite increased reinterventions and lower reintervention-free survival, the value for patients with CMI was higher in those who underwent ER in the largest propensity score-matched cohort to date looking at long-term value. Factors negatively associated with value were OR, age, days in intensive care, congestive heart failure, dysrhythmia, and cancer. In patients with amenable anatomy, ER is validated as the first-choice treatment for CMI based on the superior procedural value.

Systemic immunosuppression does not affect revascularization outcomes in patients with chronic limb-threatening ischemia.

OBJECTIVE: Many patients with chronic limb-threatening ischemia (CLTI) have additional comorbidities requiring systemic immunosuppression. Few studies have analyzed whether these medications may inhibit graft integration and effectiveness, or conversely, whether they may prevent inflammation and/or restenosis. Therefore, our study aim was to examine the effect of systemic immunosuppression vs no immunosuppression on outcomes after any first-time lower extremity revascularization for CLTI. METHODS: We identified all patients undergoing first-time infrainguinal bypass graft (BPG) or percutaneous transluminal angioplasty with or without stenting (PTA/S) for CLTI at our institution between 2005 and 2014. Patients were stratified by procedure type and immunosuppression status, defined as ≥6 weeks of any systemic immunosuppression therapy ongoing at the time of intervention. Immunosuppression vs nonimmunosuppression were the primary comparison groups in our analyses. Primary outcomes included perioperative complications, reintervention, primary patency, and limb salvage, with Kaplan-Meier and Cox proportional hazard models used for univariate and multivariate analyses, respectively. RESULTS: Among 1312 patients, 667 (51%) underwent BPG and 651 (49%) underwent PTA/S, of whom 65 (10%) and 95 (15%) were on systemic immunosuppression therapy, respectively. Whether assessing BPG or PTA/S patients, there were no differences noted in perioperative outcomes, including perioperative mortality, myocardial infarction, stroke, hematoma, or surgical site infection (P > .05). For BPG patients, Kaplan-Meier analysis and log-rank testing demonstrated no significant difference in three-year reintervention (37% vs 33% [control]; P = .75), major amputation (27% vs 15%; P = .64), or primary patency (72% vs 66%; P = .35) rates. Multivariate analysis via Cox regression confirmed these findings (immunosuppression hazard ratio [HR] for reintervention, 0.95; 95% CI, 0.56-1.60; P = .85; for major amputation, HR, 1.44; 95% CI, 0.70-2.96; P = .32; and for primary patency. HR, 0.97; 95% CI, 0.69-1.38; P = .88). For PTA/S patients, univariate analysis revealed similar rates of reintervention (37% vs 39% [control]; P = .57) and primary patency (59% vs 63%; P = .21); however, immunosuppressed patients had higher rates of major amputation (23% vs 12%; P = .01). After using Cox regression to adjust for baseline demographics, as well as operative and anatomic characteristics, immunosuppression was not associated with any differences in reintervention (HR, 0.75; 95% CI, 0.49-1.16; P = .20), major amputation (HR, 1.46; 95% CI, 0.81-2.62; P = .20), or primary patency (HR, 0.84; 95% CI, 0.59-1.19; P = .32). Sensitivity analyses for the differences in makeup of immunosuppression regimens (steroids vs other classes) did not alter the interpretation of any findings in either BPG or PTA/S cohorts. CONCLUSIONS: Our findings demonstrate that patients with chronic systemic immunosuppression, as compared with those who are not immunosuppressed, does not have a significant effect on late outcomes after lower extremity revascularization, as measured by primary patency, reintervention, or major amputation.

Comparison of endovascular therapies for chronic limb-threatening ischemia and claudication.

OBJECTIVE: Analysis of regional data from the Vascular Quality Initiative (VQI) suggested improved survival for patients undergoing stent placement compared with balloon angioplasty and atherectomy. Using national data from the VQI linked to Medicare claims data through the Vascular Implant Surveillance and Interventional Outcomes Network program, this study aimed to compare the rates of mortality, reintervention, and amputation after endovascular interventions (atherectomy, stenting, and balloon angioplasty) for two separate cohorts: patients with chronic limb-threatening ischemia (CLTI) and patients with claudication. METHODS: This was a secondary data analysis of Society for Vascular Surgery National VQI data linked to Medicare claims, between October 2016 and December 2019. Patients aged ≥65 years with symptoms of claudication or CLTI and a diagnosis of occlusive disease were included. Urgent or emergent interventions or those with concurrent procedures (endarterectomy, bypass, or bilateral intervention) were excluded. Interventions were grouped into (1) balloon angioplasty only; (2) stent (with or without balloon angioplasty); or (3) atherectomy (alone, with or without stent, with or without balloon angioplasty). Propensity score-matched cohorts were constructed to conduct pairwise intervention comparisons of mortality, reintervention, and amputation rates. Multivariable logistic regression was used to derive propensity scores for each patient. Kaplan-Meier estimates and Cox proportional hazards ratios (HRs) (95% confidence interval [CI]) analyses were performed. RESULTS: A total of 9785 (2665 claudication, 7120 CLTI) eligible patients were identified. After propensity score matching for the CLTI group, 2826, 3608, and 2796 pairs of cases were used to compare balloon angioplasty vs atherectomy, balloon angioplasty vs stent, and stent vs atherectomy, respectively. No statistically significant difference in mortality was observed among all interventions. However, atherectomy was associated with a significant increase in reintervention rate compared with balloon angioplasty (HR, 1.22; 95% CI, 1.06-1.39; P = .01) and compared with stenting (HR, 1.27; 95% CI, 1.10-1.46; P < .01) within the first year after the index procedure. Of note, both atherectomy (HR, 0.82; 95% CI, 0.68-0.98; P < .05) and stenting (HR, 0.76; 95% CI, 0.64-0.90; P < .01) showed lower rates of major amputation when compared with balloon angioplasty within 1 year after the index procedure. In the claudication group, there were no significant differences observed among interventions for peripheral arterial disease for mortality, reintervention, or amputation rates. CONCLUSIONS: Further studies are needed to identify appropriate indications for atherectomy, because there may be a subset of patients with CLTI who benefit from this therapy with respect to amputation rates. Until then, caution should be exercised when using atherectomy because it is also associated with higher reintervention rates.

Outcomes of lower extremity arterial bypass using the Human Acellular Vessel in patients with chronic limb-threatening ischemia.

OBJECTIVE: Patients with chronic limb-threatening ischemia (CLTI) and no great saphenous vein to use as a conduit for arterial bypass have a high risk for amputation despite advances in medical and endovascular therapies. This report presents findings from a U.S. Food and Drug Administration (FDA) supported study of the Human Acellular Vessel (HAV) (Humacyte Inc.) used as a conduit for arterial bypass in patients with CLTI and inadequate or absent autologous conduit. METHODS: The HAV is a 6-mm, 40-cm vessel created from human vascular smooth muscle cells seeded onto a polyglycolic acid scaffold pulsed in a bioreactor for 8 weeks as cells proliferate and the scaffold dissolves. The resultant vessel is decellularized, creating a nonimmunogenic conduit composed of collagen, elastin, and extracellular matrix. The FDA issued an Investigational New Drug for an intermediate-sized, single-center study of the HAV under the agency's Expanded Access Program in patients with advanced CLTI and inadequate or absent autologous conduit. Technical results and clinical outcomes were analyzed and reported. RESULTS: Between March 2021 and July 2023, 29 patients (20 males; mean age, 71 ± 11 years) underwent limb salvage operation using the HAV as a bypass conduit. Most patients had advanced CLTI (Rutherford class 5/6 in 72%; wound, ischemia, and foot infection stage 3/4 in 83%), and 97% had previously failed revascularization(s) of the extremity. Two HAVs were sewn together to attain the needed bypass length in 24 patients (83%). Bypasses were to tibial arteries in 23 patients (79%) and to the popliteal artery in 6 (21%). Technical success was 100%, and the 30-day mortality rate was 7% (2 patients). With 100% follow-up (median, 9.3 months), the limb salvage rate was 86% (25/29 patients). There were 16 reinterventions to restore secondary patency, of which 15 (94%) were successful. Primary and secondary patency of the HAV at 9 months were 59% and 71%, respectively. CONCLUSIONS: The HAV has demonstrated short- to intermediate-term safety and efficacy as an arterial bypass conduit in a complex cohort of patients with limb-threatening ischemia and no autologous options. This experience using the FDA's Expanded Access Program provides real-world data to inform regulatory deliberations and future trials of the HAV, including the study of the vessel as a first-line bypass conduit in less severe cases of chronic limb ischemia.

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

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

Percutaneous thrombectomy for acute limb ischemia is associated with equivalent limb and mortality outcomes compared with open thrombectomy.

BACKGROUND: Acute limb ischemia (ALI) carries a 15% to 20% risk of combined death or amputation at 30 days and 50% to 60% at 1 year. Percutaneous mechanical thrombectomy (PT) is an emerging minimally invasive alternative to open thrombectomy (OT). However, ALI thrombectomy cases are omitted from most quality databases, limiting comparisons of limb and survival outcomes between PT and OT. Therefore, our aim was to compare in-hospital outcomes between PT and OT using the National Inpatient Sample. METHODS: We analyzed survey-weighted National Inpatient Sample data (2015-2020) to include emergent admissions of aged adults (50+ years) with a primary diagnosis of lower extremity ALI undergoing index procedures within 2 days of hospitalization. We excluded hospitalizations with concurrent trauma or dissection diagnoses and index procedures using catheter-directed thrombolysis. Our primary outcome was composite in-hospital major amputation or death. Secondary outcomes included in-hospital major amputation, death, in-hospital reintervention (including angioplasty/stent, thrombolysis, PT, OT, or bypass), and extended length of stay (eLOS; defined as LOS >75th percentile). Adjusted odds ratios (aORs) with 95% confidence intervals (95% CIs) were generated by multivariable logistic regression, adjusting for demographics, frailty (Risk Analysis Index), secondary diagnoses including atrial fibrillation and peripheral artery disease, hospital characteristics, and index procedure data including the anatomic thrombectomy level and fasciotomy. A priori subgroup analyses were performed using interaction terms. RESULTS: We included 23,795 survey-weighted ALI hospitalizations (mean age: 72.2 years, 50.4% female, 79.2% White, and 22.3% frail), with 7335 (30.8%) undergoing PT. Hospitalization characteristics for PT vs OT differed by atrial fibrillation (28.7% vs 36.5%, P < .0001), frequency of intervention at the femoropopliteal level (86.2% vs 88.8%, P = .009), and fasciotomy (4.8% vs 6.9%, P = .006). In total, 2530 (10.6%) underwent major amputation or died. Unadjusted (10.1% vs 10.9%, P = .43) and adjusted (aOR = 0.96 [95% CI, 0.77-1.20], P = .74) risk did not differ between the groups. PT was associated with increased odds of reintervention (aOR = 2.10 [95% CI, 1.72-2.56], P < .0001) when compared with OT, but this was not seen in the tibial subgroup (aOR = 1.31 [95% CI, 0.86-2.01], P = .21, Pinteraction < .0001). Further, 79.1% of PT hospitalizations undergoing reintervention were salvaged with endovascular therapy. Lastly, PT was associated with significantly decreased odds of eLOS (aOR = 0.80 [95% CI, 0.69-0.94], P = .005). CONCLUSIONS: PT was associated with comparable in-hospital limb salvage and mortality rates compared with OT. Despite an increased risk of reintervention, most PT reinterventions avoided open surgery, and PT was associated with a decreased risk of eLOS. Thus, PT may be an appropriate alternative to OT in appropriately selected patients.

Safety and efficacy of mechanical aspiration thrombectomy for patients with acute lower extremity ischemia.

OBJECTIVE: Acute limb ischemia (ALI) is associated with high rates of amputation and consequent morbidity and mortality. The objective of this study is to report on the safety and efficacy of aspiration thrombectomy using the Indigo Aspiration System in patients with lower extremity (LE) ALI. METHODS: The STRIDE study was an international, multicenter, prospective, study that enrolled 119 participants presenting with LE-ALI. Patients were treated firstline with mechanical thrombectomy using the Indigo Aspiration System, before stenting or angioplasty, or other therapies as determined by treating physician. The primary end point was target limb salvage at 30 days after the procedure. Secondary end points within 30 days included technical success, defined as core laboratory-adjudicated Thrombolysis in Myocardial Infarction (TIMI) 2/3 flow rate immediately after the procedure, changes in modified Society for Vascular Surgery runoff score, improvement of Rutherford classification compared with before the procedure, patency, rate of device-related serious adverse events, and major periprocedural bleeding. Secondary end points that will be evaluated at 12 months include target limb salvage and mortality. RESULTS: Of the 119 participants enrolled at 16 sites, the mean age was 66.3 years (46.2% female). At baseline (n = 119), ischemic severity was classified as Rutherford I in 10.9%, Rutherford IIa in 54.6%, and Rutherford IIb in 34.5%. The mean target thrombus length was 125.7 ± 124.7 mm. Before the procedure, 93.0% (of patients 107/115) had no flow (TIMI 0) through the target lesion. The target limb salvage rate at 30 days was 98.2% (109/111). The rate of periprocedural major bleed was 4.2% (5/119) and device-related serious adverse events was 0.8% (1/119). Restoration of flow (TIMI 2/3) was achieved in 96.3% of patients (105/109) immediately after the procedure. The median improvement in the modified Society for Vascular Surgery runoff score (before vs after the procedure) was 6.0 (interquartile range, 0.0-11.0). Rutherford classifications also improved after discharge in 86.5% of patients (83/96), as compared with preprocedural scores. Patency at 30 days was achieved in 89.4% of patients (101/113). CONCLUSIONS: In the STRIDE (A Study of Patients with Lower Extremity Acute Limb Ischemia to Remove Thrombus with the Indigo Aspiration System) study, aspiration thrombectomy with the Indigo System provided a safe and effective endovascular treatment for patients with LE-ALI, resulting in a high rate (98.2%) of successful limb salvage at 30 days, with few periprocedural complications.

Percutaneous Deep Venous Arterialization in Patients with No-Option Critical Limb Ischemia Performed in an Office-Based Laboratory Setting.

PURPOSE: To evaluate the feasibility and safety of percutaneous deep venous arterialization (pDVA) performed in an office-based laboratory (OBL) for patients with no-option critical limb ischemia (CLI). MATERIALS AND METHODS: A retrospective chart review was performed of all patients who underwent pDVA using commercially available devices from January 2018 to November 2021 in a single OBL. In total, 22 patients (10 males and 12 females; Rutherford 4, 5, and 6: n = 1, 8, and 13, respectively) were identified with a median follow-up of 140 days. Amputation-free survival, wound healing, pDVA patency, and overall survival were evaluated at 30 days, 6 months, and throughout the remaining follow-up period. RESULTS: All patients had undergone failed previous attempts at endovascular arterial reconstruction. At 6 months after procedure, 6.4% of arteriovenous conduits remained patent; 83.3% (10/12) of patients experienced complete or partial wound healing. In addition, 78.6% of patients avoided an above-ankle amputation, and overall survival was 83.6%. Nine patients underwent endovascular reinterventions at 6 months. One mild adverse event and 4 moderate adverse events occurred after procedure, and 1 cardiac death occurred 5 days after procedure. CONCLUSIONS: pDVA is safe and feasible in the OBL for patients with no-option CLI. Many patients avoided an above-ankle amputation during the study period despite low overall pDVA patency.

Percutaneous Management of Dialysis Access Steal Syndrome: Interventions and Outcomes from a Single Institution's 20-Year Experience.

PURPOSE: To determine safety and effectiveness of percutaneous interventions performed by interventional radiologists at a single institution over 2 decades in patients with dialysis access steal syndrome (DASS). MATERIALS AND METHODS: A retrospective review of fistulograms from 2001 to 2021 (N = 11,658) was performed. In total, 286 fistulograms in 212 patients with surgically created dialysis accesses met inclusion criterion of fistulography for suspected DASS. Chart review collected data regarding patient demographics, comorbidities, access characteristics, fistulography findings, intervention(s) performed, and outcomes. Procedures with and without DASS intervention were compared. Odds ratios (ORs), adjusted for age, sex, comorbidities, access characteristics, and multiple within-patient events, were calculated using logistic regression to determine associations between steal intervention status and outcome variables: (a) major adverse events, (b) access preservation, and (c) follow-up surgery. A percutaneously treatable cause of DASS was present in 128 cases (45%). Treatment of DASS lesions was performed in 118 cases. Fifteen embolizations were also performed in patients without DASS lesions. RESULTS: Technical success of DASS interventions, defined by the Society of Interventional Radiology (SIR) reporting standards, was 94%; 54% of interventions resulted in DASS symptom improvement at a median follow-up of 15 days. Patients with steal intervention had 60% lower odds of follow-up surgery (OR, 0.4; P = .007). There was no difference in major adverse events (P = .98) or access preservation (P = .13) between groups. CONCLUSIONS: In this retrospective cohort study, approximately half of DASS fistulograms revealed a percutaneously treatable cause of steal. Over half of DASS interventions resulted in symptomatic relief. Percutaneous intervention was associated with lower odds of follow-up surgery without compromising access preservation.

Association between End-Stage Renal Disease and Major Adverse Limb Events after Peripheral Vascular Intervention.

PURPOSE: To examine the effect of end-stage renal disease (ESRD) on the likelihood of major adverse limb events (MALEs) in patients with Rutherford Category 4-6 critical limb ischemia (CLI) who underwent percutaneous vascular intervention (PVI). MATERIALS AND METHODS: Two contemporaneous cohorts of patients who underwent PVI for symptomatic CLI from 2012 to 2022, differing in ESRD status, were matched using propensity score methods. This database identified 628 patients who underwent 1,297 lower extremity revascularization procedures; propensity score matching yielded 147 patients (180 limbs, 90 limbs in each group). Kaplan-Meier and Cox proportional hazard analyses were used to assess the effect of ESRD status on MALEs, stratified into major amputation (further stratified into above-knee amputation and below-knee amputation [BKA]) and reintervention (PVI or bypass). RESULTS: After PVI, 31.3% of patients in the matched cohorts experienced a MALE (45.7% ESRD vs 18.2% non-ESRD), and 15.6% experienced a major amputation (27.1% ESRD vs 5.2% non-ESRD). Cox proportional hazards analysis revealed that ESRD was an independent predictor of MALE (hazard ratio [HR], 3.15; 95% CI, 1.58-6.29; P = .001), major amputation (HR, 7.00; 95% CI, 2.06-23.79; P = .002), and BKA (HR, 7.56; 95% CI, 1.71-33.50; P = .008). CONCLUSIONS: ESRD is strongly predictive of MALE and major amputation risk, specifically BKA, in patients undergoing PVI for Rutherford Category 4-6 CLI. These patients warrant closer follow-up, and new methods may become necessary to predict and further reduce their amputation risk.

Evaluation of short-term mortality in patients with Medicare undergoing endovascular interventions for chronic limb-threatening ischemia.

INTRODUCTION: Patients with chronic limb-threatening ischemia (CLTI) have high mortality rates after revascularization. Risk stratification for short-term outcomes is challenging. We aimed to develop machine-learning models to rank predictive variables for 30-day and 90-day all-cause mortality after peripheral vascular intervention (PVI). METHODS: Patients undergoing PVI for CLTI in the Medicare-linked Vascular Quality Initiative were included. Sixty-six preprocedural variables were included. Random survival forest (RSF) models were constructed for 30-day and 90-day all-cause mortality in the training sample and evaluated in the testing sample. Predictive variables were ranked based on the frequency that they caused branch splitting nearest the root node by importance-weighted relative importance plots. Model performance was assessed by the Brier score, continuous ranked probability score, out-of-bag error rate, and Harrell's C-index. RESULTS: A total of 10,114 patients were included. The crude mortality rate was 4.4% at 30 days and 10.6% at 90 days. RSF models commonly identified stage 5 chronic kidney disease (CKD), dementia, congestive heart failure (CHF), age, urgent procedures, and need for assisted care as the most predictive variables. For both models, eight of the top 10 variables were either medical comorbidities or functional status variables. Models showed good discrimination (C-statistic 0.72 and 0.73) and calibration (Brier score 0.03 and 0.10). CONCLUSION: RSF models for 30-day and 90-day all-cause mortality commonly identified CKD, dementia, CHF, need for assisted care at home, urgent procedures, and age as the most predictive variables as critical factors in CLTI. Results may help guide individualized risk-benefit treatment conversations regarding PVI.

Comparison of Transcatheter Arterialization of Deep Veins to Standard of Care in Patients with No-Option Chronic Limb Threatening Ischemia.

BACKGROUND: Patients with no-option chronic limb-threatening ischemia (no-option CLTI) have limited therapeutic options. The PROMISE II study evaluated, transcatheter arterialization of deep veins (TADV) as a treatment option for no-option CLTI. In the current study patients from PROMISE II were compared to patients from a registry of untreated no-option CLTI patients (CLariTI: Natural Progression of High-Risk Chronic Limb-Threatening Ischemia). METHODS: We used propensity matching to compare patients from the PROMISE II prospective study of the TADV intervention with simultaneously enrolled CLTI patients that were note candidates for PROMISE II but were enrolled in to CLariTI natural history registry. Untreated no-option CLTI (CLariTI) patients could either be no-option or patients who did not meet PROMISE II entry criteria. Risk difference between groups was calculated using common risk difference and P values were provided by propensity-score stratified Mantel-Haenszel test. The primary endpoint was amputation-free survival (AFS). RESULTS: Diabetes was present in over 75% of patients. All patients had tissue loss and 35-46% had extensive tissue loss (Rutherford 6). The unadjusted AFS at 6 months, was 66.1% by Kaplan-Meier estimate for PROMISE II patients (n = 105) compared to 39.1% in the no-option cohort of CLariTI (n = 121) and 44.0% in the full cohort (no-option and patients not meeting entry criteria combine, n = 180). The treatment group who underwent TADV for no-option CLTI had an absolute difference of 29% improved (P < 0.0001) propensity-adjusted risk difference in AFS and a relative event rate reduction of 45% compared to the no-option control patients. CONCLUSIONS: Transcatheter arterialization of deep veins (TADV) resulted in improved 6 month AFS in no-option CLTI patients and appears to be a promising therapy in patients with no-option CLTI.

Role of Anticoagulation in Nonagenarian Patients with Acute Limb Ischemia.

BACKGROUND: Preoperative anticoagulant therapy is known to have a positive impact on the prognosis of patients with acute limb ischemia (ALI). However, little is known about its efficacy in elderly patients. We aimed to investigate the potential effect of anticoagulation in nonagenarian patients managed for ALI. METHODS: Between January 2015 and December 2021, we identified all nonagenarian patients managed for ALI at a single center. Long-term anticoagulation and hemostasis parameters (prothrombin rate, activated partial thromboplastin time [APTT], platelet count) measured on admission were reviewed. The primary end point was mortality at 30-day mortality (D30) in patients with or without long-term anticoagulation therapy. We also studied the effect of these factors on the occurrence of revascularization failure in operated patients (initial failure, ischemic recurrence during hospitalization, necrosis requiring major amputation). RESULTS: A total of 68 nonagenarian patients were managed for ALI, with a mean age of 93.8 years (from 90-107 years), 76.5% of whom were women. Of these patients, 47 (69%) were managed surgically. Long-term anticoagulation therapy was associated with better survival at D30, both in nonoperated (P < 0.01) and operated (P < 0.05) patients. In operated patients, the absence of long-term anticoagulation therapy was associated with the occurrence of revascularization failure (P < 0.05). In operated patients, survival to D30 and successful revascularization were associated with a longer APTT (P < 0,05). We were able to observe the survival of 4 patients contraindicated for surgery and treated with a single medical therapy (intravenous unfractionated heparin). CONCLUSIONS: Anticoagulation appears to have an impact on the survival and postoperative prognosis of nonagenarian patients with ALI. In addition, curative anticoagulation therapy may be an alternative treatment when surgery is contraindicated in this frail population.

Outcomes of Endovascular Treatment for Critical Limb Threatening Ischemia.

BACKGROUND: Critical limb threatening ischemia (CLTI), particularly in patients with ischemic ulceration has been associated with significant morbidity and mortality. Typically, endovascular therapy has been first-line therapy for our patients, but this strategy has come into question based upon the Best Endovascular versus Best Surgical Therapy in Patients with Critical Limb Threatening Ischemia (BEST-CLI) trial data. METHODS AND RESULTS: For comparative purposes, we evaluated outcomes from 150 CLTI patients with ischemic ulceration treated with endovascular-first therapy. The mean age was 72 years in this predominate male, Caucasian, ambulatory group. The major co-morbidities were smoking history in 49% and diabetes mellitus in 67%.` Anatomic scoring, using Society for Vascular Surgery criteria, revealed only 35.6% had favorable anatomy (Global Limb Anatomical Staging System stage of 0,1) for long-term patency compared to 64.4% of limbs with unfavorable anatomy for long-term patency (Global Limb Anatomical Staging System stage 2,3). Stents were used in 47% of cases. Reintervention occurred in 36% over 24 months follow-up. At 12 and 24 months, the Kaplan-Meier projections for survival was 0.80 (0.73, 0.87) and 0.69 (0.59, 0.79); amputation was 0.69 (0.61, 0.77) and 0.59 (0.46, 0.71); amputation-free survival (AFS) was 0.56 (0.48, 0.65) and 0.38 (0.27, 0.50), respectively. Amputation was more common in those with reinterventions (P = 0.033). Mortality was predicted with ankle brachial index ≤0.40 or ≥1.30 (P = 0.0019) and the presence of infection (P = 0.0047). AFS was predicted by the presence of any infection (P = 0.0001). CONCLUSIONS: Despite technically successful endovascular treatment, patients who present with CLTI maintain a high-risk for limb loss and mortality. Amputation prevention must vigilantly address infection risk. These data correlate with outcomes from BEST-CLI trial enhancing applicability to patient-centered care.

Peak Aortic Valve Jet Velocity is an Independent Predictor of Mortality of Dialysis Patients Undergoing Open Surgery for Chronic Limb Threatening Ischemia.

BACKGROUND: To investigate the impact of peak aortic jet velocity (Vmax) on the prognosis of patients undergoing open surgery for chronic limb threatening ischemia (CLTI). METHODS: Between April 2015 and March 2022, 352 patients underwent infrainguinal open surgery for CLTI. Patients who met the following exclusion criteria were excluded: subsequent infrainguinal surgeries in the registered period, no record of Vmax, history of aortic valve intervention, and Vmax ≥3.0 m/s (moderate or severe aortic valve stenosis). The remaining patients were dichotomized into 2 groups based on their Vmax values. The Youden index calculated from the receiver operating characteristic curve (ROC) was set as the cutoff value. The 2-year overall survival (OS), calculated using the Kaplan-Meier's method, was compared between the 2 groups. A Cox proportional hazards regression analysis was performed using perioperative factors including Vmax to identify independent predictors separately for dialysis and nondialysis patients and the quantitative relationship between Vmax and OS. RESULTS: One hundred and ninety-one patients, including 100 dialysis and 91 nondialysis patients, were included in the analysis. The Youden index was 1.7 m/s. The 2-year OS rates of the group with Vmax >1.7 m/s and with Vmax ≤1.7 m/s were 49% and 76% (P = 0.007), respectively, in the dialysis cohort, while they were 71% and 78% (P = 0.680) in the nondialysis cohort, respectively. Multivariate analysis identified Vmax and ejection fraction as independent predictors in the dialysis cohort and the Barthel Index at admission in the nondialysis cohort. There was a stepwise increase in the risk of death in patients with Vmax of ≥1.5 m/s and a significantly higher risk of death in dialysis patients with Vmax >2.5 m/s. CONCLUSIONS: Vmax was a significant independent predictor of all-cause death within 2 years after open surgery for CLTI in dialysis patients but not in patients managed without dialysis.

Heparin-Bonded Expanded Polytetrafluoroethylene Is a Solution for Infrapopliteal Revascularization in the Absence of an Adequate Autologous Vein Graft.

BACKGROUND: To analyze the outcomes of heparin-bonded expanded polytetrafluoroethylene (HePTFE) graft as an alternative conduit in infrapopliteal revascularization of chronic limb-threatening ischemia (CLTI) in the absence of an autologous vein conduit. METHODS: A single-center retrospective analysis of patients with CLTI submitted to infrapopliteal bypasses with autologous vein graft (VEIN group) or HePTFE graft (HePTFE group) was implemented. Primary end points were freedom from CLTI at 12 months and recurrence of CLTI at 3 years. Secondary end points included freedom from major amputation, amputation-free survival (AFS), survival, and primary (PP) and secondary patency (SP) rates at 3 years of follow-up. RESULTS: A total of 348 limbs submitted to infrapopliteal bypasses, 214 with venous graft and 134 with HePTFE graft, were followed-up for a median of 25 months. Most patients of the HePTFE group were male (69%), with a median age of 76 years (interquartile range [IQR] 15). Fifty-nine percent of the limbs of the HePTFE group had Wound grade ≥2, being 46% of them infected. Eighty-eight percent were GLASS stage III. Freedom from CLTI was not significantly different between HePTFE and VEIN groups (75% vs. 84%, adjusted hazard ratio [aHR] 0.88, confidence interval [CI] 0.66-1.18, P = 0.401). Recurrence of CLTI was higher in the HePTFE group (42% vs.18% at 3 years; aHR 2.82, CI 1.59-5.00, P < 0.001). The VEIN group achieved higher rates of freedom from major amputation (87% vs.69% at 3 years; aHR 2.21, CI 1.31-3.75, P = 0.003) and AFS (59% vs. 37% at 3 years; aHR 1.39, CI 1.02-1.88, P = 0.036), but no significance in survival (aHR 1.10, CI 0.72-1.66, P = 0.667). Patency rates were inferior in the HePTFE group, with 2-year PP and SP rates of 52% vs. 74%, and 76% vs. 90%, respectively (PP: aHR 1.70, CI 1.11-2.59, P = 0.014; SP: aHR 2.51, CI 1.42-4.42, P = 0.001). CONCLUSIONS: Infrapopliteal bypass with autologous vein graft is the gold standard to treat CLTI limbs. HePTFE graft should be regarded as an alternative for complex infrapopliteal revascularization when lacking an autologous vein conduct.

Endovascular Denervation for the Improvement of Limb Ischemia in Patients with Peripheral Artery Disease: A Randomized Clinical Trial.

BACKGROUND: To evaluate the safety and efficacy of endovascular denervation (EDN) as an adjunct to percutaneous vascular intervention (PVI) for peripheral artery disease (PAD). METHODS: From August 2019 to April 2021, 38 eligible patients with PAD enrolled in this study were randomly and equally assigned into 2 groups: the PVI group and the PVI + EDN group treated with EDN at the iliac and femoral arteries before PVI. The primary endpoint was the improvement in the ankle brachial index at 6 months after the procedure. The secondary endpoints were transcutaneous oxygen pressure (TcPO2), Rutherford category, numerical rating scale score, and safety. RESULTS: The technical success rates of PVI and EDN were 100%, and no device-related or procedure-related major adverse events occurred in either group. Compared with PVI alone, PVI + EDN demonstrated a significant improvement in limb hemodynamics at 6 months (Δ ankle brachial index 0.44 ± 0.31 vs. 0.24 ± 0.15, P = 0.018). Microcirculatory perfusion of PAD was significantly better at 6 months in the PVI + EDN group (ΔTcPO2, 15.68 ± 16.72 vs. 4.95 ± 13.43, P = 0.036). The Rutherford category was significantly improved in the PVI + EDN group in comparison with the PVI group at the 3-month follow-up (100.00% vs. 68.42%, P = 0.02). The decrease in the numerical rating scale score in the PVI + EDN group was greater than that in the PVI group at 1 week following the procedure (3 [2-5] vs. 4 [4-6], P = 0.022). CONCLUSIONS: In this single-center pilot analysis of a heterogeneous cohort of patients with PAD, PVI with EDN demonstrated a significant improvement in limb ischemia at 6 months compared with PVI alone.