Transcatheter Arterialization of the Deep Veins for Limb Salvage.

Critical limb-threatening ischemia is the most advanced stage of peripheral arterial disease, and patients with this problem represent a group at very high risk of limb loss. Until recently, patients with severe disease in the foot that was unreconstructable through the arterial system were relegated to treatment with wound care, pain management, and ultimately often faced major amputation. In recent investigations into the use of a percutaneous approach to venous arterialization, transcatheter arterialization of the deep veins has been evaluated as a mechanism to improve oxygen delivery to the foot in patients faced with the prospect of limb loss. Identifying patients who would benefit from this approach and a critical evaluation of the technique are provided along with expected outcomes. While the procedure remains in its infancy, early outcomes are promising, and continued advancement and improvement will further enhance options for these patients.

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.

An international, multispecialty, expert-based Delphi Consensus document on controversial issues in the management of patients with asymptomatic and symptomatic carotid stenosis.

OBJECTIVE: Despite the publication of various national/international guidelines, several questions concerning the management of patients with asymptomatic (AsxCS) and symptomatic (SxCS) carotid stenosis remain unanswered. The aim of this international, multi-specialty, expert-based Delphi Consensus document was to address these issues to help clinicians make decisions when guidelines are unclear. METHODS: Fourteen controversial topics were identified. A three-round Delphi Consensus process was performed including 61 experts. The aim of Round 1 was to investigate the differing views and opinions regarding these unresolved topics. In Round 2, clarifications were asked from each participant. In Round 3, the questionnaire was resent to all participants for their final vote. Consensus was reached when ≥75% of experts agreed on a specific response. RESULTS: Most experts agreed that: (1) the current periprocedural/in-hospital stroke/death thresholds for performing a carotid intervention should be lowered from 6% to 4% in patients with SxCS and from 3% to 2% in patients with AsxCS; (2) the time threshold for a patient being considered "recently symptomatic" should be reduced from the current definition of "6 months" to 3 months or less; (3) 80% to 99% AsxCS carries a higher risk of stroke compared with 60% to 79% AsxCS; (4) factors beyond the grade of stenosis and symptoms should be added to the indications for revascularization in AsxCS patients (eg, plaque features of vulnerability and silent infarctions on brain computed tomography scans); and (5) shunting should be used selectively, rather than always or never. Consensus could not be reached on the remaining topics due to conflicting, inadequate, or controversial evidence. CONCLUSIONS: The present international, multi-specialty expert-based Delphi Consensus document attempted to provide responses to several unanswered/unresolved issues. However, consensus could not be achieved on some topics, highlighting areas requiring future research.

Automated Measurement of Vascular Calcification in Femoral Endarterectomy Patients Using Deep Learning.

Atherosclerosis, a chronic inflammatory disease affecting the large arteries, presents a global health risk. Accurate analysis of diagnostic images, like computed tomographic angiograms (CTAs), is essential for staging and monitoring the progression of atherosclerosis-related conditions, including peripheral arterial disease (PAD). However, manual analysis of CTA images is time-consuming and tedious. To address this limitation, we employed a deep learning model to segment the vascular system in CTA images of PAD patients undergoing femoral endarterectomy surgery and to measure vascular calcification from the left renal artery to the patella. Utilizing proprietary CTA images of 27 patients undergoing femoral endarterectomy surgery provided by Prisma Health Midlands, we developed a Deep Neural Network (DNN) model to first segment the arterial system, starting from the descending aorta to the patella, and second, to provide a metric of arterial calcification. Our designed DNN achieved 83.4% average Dice accuracy in segmenting arteries from aorta to patella, advancing the state-of-the-art by 0.8%. Furthermore, our work is the first to present a robust statistical analysis of automated calcification measurement in the lower extremities using deep learning, attaining a Mean Absolute Percentage Error (MAPE) of 9.5% and a correlation coefficient of 0.978 between automated and manual calcification scores. These findings underscore the potential of deep learning techniques as a rapid and accurate tool for medical professionals to assess calcification in the abdominal aorta and its branches above the patella.

Wildfire and cattle legacies on gradients of soil nitrogen underlie patterns of annual brome invasion.

Human activities are increasing wildfires and livestock activity in arid ecosystems with potential implications for the spread of invasive grasses. The objective of this study was to test whether fire history and cattle activity alter soil resource gradients, thereby affecting patterns of Bromus rubens L. (red brome) invasion. Six paired burned and unburned transect lines (1-km long) were established in the northeast Mojave Desert along the boundaries of four independent wildfire scars. At 100-m transect increment points, we measured the distance to the two nearest cowpats, and two random points and measured the density, height, biomass, and seed production of red brome, soil moisture and inorganic nitrogen (N). Cattle activity was 29% greater along burned transects compared to unburned transects (P < 0.05). Red brome height, density, and seed production were 11-34% greater along burned transects than unburned transects (P < 0.05). Red brome height, biomass, density, and seed production were twofold to tenfold greater next to cowpats compared to random points (P < 0.05). Soils along burned transects and beneath cowpats had greater soil inorganic N (P < 0.05), which was positively correlated with red brome density, height, biomass, and seed production (R2 = 0.60-0.85, P < 0.0001). Transgenerational effects were evident as seeds from red brome next to cowpats had 27% higher germination than seeds collected from random points. Positive responses of red brome to increased inorganic N related to fire and cattle activity may contribute fine fuel infill that drives invasive grass-fire cycles in deserts.

Transcatheter Arterialization of Deep Veins in Chronic Limb-Threatening Ischemia.

BACKGROUND: Approximately 20% of patients with chronic limb-threatening ischemia have no revascularization options, leading to above-ankle amputation. Transcatheter arterialization of the deep veins is a percutaneous approach that creates an artery-to-vein connection for delivery of oxygenated blood by means of the venous system to the ischemic foot to prevent amputation. METHODS: We conducted a prospective, single-group, multicenter study to evaluate the effect of transcatheter arterialization of the deep veins in patients with nonhealing ulcers and no surgical or endovascular revascularization treatment options. The composite primary end point was amputation-free survival (defined as freedom from above-ankle amputation or death from any cause) at 6 months, as compared with a performance goal of 54%. Secondary end points included limb salvage, wound healing, and technical success of the procedure. RESULTS: We enrolled 105 patients who had chronic limb-threatening ischemia and were of a median age of 70 years (interquartile range, 38 to 89). Of the patients enrolled, 33 (31.4%) were women and 45 (42.8%) were Black, Hispanic, or Latino. Transcatheter arterialization of the deep veins was performed successfully in 104 patients (99.0%). At 6 months, 66.1% of the patients had amputation-free survival. According to Bayesian analysis, the posterior probability that amputation-free survival at 6 months exceeded a performance goal of 54% was 0.993, which exceeded the prespecified threshold of 0.977. Limb salvage (avoidance of above-ankle amputation) was attained in 67 patients (76.0% by Kaplan-Meier analysis). Wounds were completely healed in 16 of 63 patients (25%) and were in the process of healing in 32 of 63 patients (51%). No unanticipated device-related adverse events were reported. CONCLUSIONS: We found that transcatheter arterialization of the deep veins was safe and could be performed successfully in patients with chronic limb-threatening ischemia and no conventional surgical or endovascular revascularization treatment options. (Funded by LimFlow; PROMISE II study ClinicalTrials.gov number, NCT03970538.).

Appropriate Use of Intravascular Ultrasound During Arterial and Venous Lower Extremity Interventions.

BACKGROUND: There has been growing use of intravascular ultrasound (IVUS) during lower extremity arterial and venous revascularization. Observational data suggest that the use of IVUS can improve periprocedural and long-term outcomes, but largescale prospective data remain limited. Consensus opinion regarding the appropriate use of IVUS during peripheral intervention is needed. OBJECTIVES: The purpose of this consensus document is to provide guidance on the appropriate use of IVUS in various phases of peripheral arterial and venous interventions. METHODS: A 12-member writing committee was convened to derive consensus regarding the appropriate clinical scenarios for use of peripheral IVUS. The group iteratively created a 72-question survey representing 12 lower extremity arterial interventional scenarios. Separately, a 40-question survey representing 8 iliofemoral venous interventional scenarios was constructed. Clinical scenarios were categorized by interventional phases: preintervention, intraprocedure, and postintervention optimization. Thirty international vascular experts (15 for each survey) anonymously completed the survey instrument. Results were categorized by appropriateness using the median value and disseminated to the voting panel to reevaluate for any disagreement. RESULTS: Consensus opinion concluded that IVUS use may be appropriate during the preintervention phase for evaluating the etiology of vessel occlusion and plaque morphology in the iliac and femoropopliteal arteries. IVUS was otherwise rated as appropriate during iliac and femoropopliteal revascularization in most other preintervention scenarios, as well as intraprocedural and postprocedural optimization phases. IVUS was rated appropriate in all interventional phases for the tibial arteries. For iliofemoral venous interventions, IVUS was rated as appropriate in all interventional phases. CONCLUSIONS: Expert consensus can help define clinical procedural scenarios in which peripheral IVUS may have value during lower extremity arterial and venous intervention while additional prospective data are collected.

Intravascular ultrasound guidance for lower extremity arterial and venous interventions.

This review details the utility of intravascular ultrasound (IVUS) for the management of peripheral artery and venous disease. The purpose of this document is to provide an update in the use of IVUS in peripheral arterial and venous pathology and demonstrate the use of IVUS as a practical diagnostic imaging procedure to evaluate and treat peripheral vascular disorders. IVUS, a diagnostic tool that relies on sound waves to produce precise images of the vessel being evaluated, was originally introduced to the medical community for the purposes of peripheral artery imaging, though it was quickly adapted for coronary interventions with positive outcomes. The utility of IVUS includes vessel measurement, pre- and post-procedural planning, treatment optimisation, and detection of thrombus, dissection or calcium severity. While angiography remains the standard imaging approach during peripheral intervention, multiple observational studies and small prospective trials have shown that in comparison, IVUS provides more accurate imaging detail, which may improve procedural outcomes. IVUS can also address limitations of angiography, including the need to administer contrast medium and eliminate the ambiguity associated with other forms of imaging. This review provides contemporary examples of where IVUS is being used during peripheral intervention as well as representative imaging to serve as a resource for the practising clinician.

Visceral segment aortic thrombus is associated with proximal aortic degeneration after infrarenal abdominal aortic aneurysm repair.

OBJECTIVE: To identify predictors of aortic aneurysm formation at or above an infrarenal abdominal aortic aneurysm repair. METHODS: A total of 881 infrarenal abdominal aortic aneurysm repairs were identified at a single institution from 2004 to 2008; 187 of the repairs were identified that had pre-operative and post-operative computed tomography imaging at least one year or greater to evaluate for aortic degeneration following repair. Aortic diameters at the celiac, superior mesenteric, and renal arteries were measured on all available computed tomographic scans. Aortic thrombus and calcification volumes in the visceral and infrarenal abdominal aortic segments were calculated. Multivariable modeling was used with log transformed variables to determine potential predictors of future aortic aneurysm development after infrarenal abdominal aortic aneurysm repair. RESULTS: Of the 187 patients in the cohort, 100 had an open abdominal aortic aneurysm repair while 87 were treated with endovascular repair. Proximal aortic aneurysms developed in 26% (n = 49) of the cohort during an average of 72 ± 34.2 months of follow-up. After multivariable modeling, visceral segment aortic thrombus on pre-operative computed tomography imaging increased the risk of aortic aneurysm development above the infrarenal abdominal aortic aneurysm repair within both the open abdominal aortic aneurysm (hazard ratio 2.04, p = 0.033) and endovascular repair (hazard ratio 3.31, p = 0.004) cohorts. Endovascular repair was independently associated with a higher risk of future aortic aneurysm development after infrarenal abdominal aortic aneurysm repair when compared to open abdominal aortic aneurysm (hazard ratio 2.19, p = 0.025). CONCLUSIONS: Visceral aortic thrombus present prior to abdominal aortic aneurysm repair and endovascular repair are both associated with an increased risk of future proximal aortic degeneration after infrarenal abdominal aortic aneurysm repair. These factors may predict patients at higher risk of developing proximal aortic aneurysms that may require complex aortic repairs.

A review of percutaneous deep vein arterialization for the treatment of nonreconstructable chronic limb threatening ischemia.

Peripheral arterial disease is estimated to affect more than 200 million people worldwide with some patients progressing to chronic limb threatening ischemia (CLTI). Patients with CLTI have extremely high rates of amputation and associated increases in morbidity and mortality. There is a subset of patients with CLTI that have no available options for revascularization due to factors such as the absence of distal target vessels or adequate conduit for surgical revascularization. Percutaneous deep vein arterialization can be used in patients with nonreconstructable CLTI. In this review article, we discuss patient selection, methods, and techniques of deep vein arterialization. In addition, results from studies evaluating the use of percutaneous deep vein arterialization, such as the Alkmaar (The Netherlands), Leipzig (Germany), Paris (France), and Singapore (ALPS) multicenter center study and the prospective, multicenter, single-arm, early feasibility (PROMISE I) trial, are highlighted. These results have been encouraging with improved rates of limb salvage and wound healing reported, suggesting percutaneous deep vein arterialization may be beneficial in treating patients with CLTI.

PROMISE I: Early feasibility study of the LimFlow System for percutaneous deep vein arterialization in no-option chronic limb-threatening ischemia: 12-month results.

OBJECTIVE: We report the 6- and 12-month outcomes of the PROMISE I early feasibility study after treatment of no-option chronic limb-threatening ischemia (CLTI) with percutaneous deep vein arterialization (pDVA) using the LimFlow System. METHODS: Thirty-two patients with no-option CLTI, previously offered major amputation, were enrolled in this single-arm early feasibility study of the LimFlow pDVA System. No-option CLTI was defined as being ineligible for surgical or endovascular arterial revascularization. Patients were assessed for clinical status, pain, wound healing, and duplex ultrasound at 30 days, 6 months, and 12 months post-treatment. Primary endpoint analysis was amputation-free survival (AFS) at 30 days and 6 and 12 months. AFS was defined as freedom from above-ankle amputation of the index limb and freedom from all-cause mortality. Secondary endpoints evaluated included technical success of the procedure, and wound healing at 6 and 12 months. RESULTS: Of 32 enrolled patients, 31 (97%) were successfully treated with the LimFlow System at the time of the procedure, and two (6.3%) were lost to follow-up. The 30-day, 6-month, and 12-month AFS rates were 91%, 74%, and 70% respectively. The wound healing status of fully healed or healing was 67% at 6 months, and 75% at 12 months. Reintervention was performed in 16 patients (52%) with 14 (88%) of the maintenance reinterventions occurring within the first 3 months. The majority of reinterventions (n = 12; 75%), involved the arterial inflow tract proximal to the stented LimFlow circuit, and no in-stent stenoses were determined to have been the cause of reintervention. CONCLUSIONS: The LimFlow pDVA System was utilized in treating patients with no-option CLTI. A high technical success rate was observed, with a significant percentage of patients surviving free of major amputation at 12 months. These results suggest early safety and provide an initial assessment of the efficacy of the LimFlow pDVA System that supports the expansion of carefully executed studies to determine whether this is a viable option that can be used in this critically disadvantaged and growing patient population.

Failure on a Vascular Surgery Board-American Board of Surgery Examination does not predict cardiovascular outcomes in the Society for Vascular Surgery Vascular Quality Initiative.

OBJECTIVE: The Vascular Surgery Board of the American Board of Surgery (VSB-ABS) Qualifying and Certifying examinations are meant to assess qualifications to independently practice vascular surgery, but it is unclear whether examination performance correlates with clinical outcomes. We assessed this relationship using clinical outcomes data for VSB-ABS diplomates from the Society for Vascular Surgery Vascular Quality Initiative (SVS-VQI). METHODS: VSB-ABS examination performance for vascular surgeons participating in the SVS-VQI registry was characterized according to pass/fail status. Surgical experience was measured by number of years since completion of training. Examination performance and experience were compared with a composite clinical outcome (in-patient major adverse cardiac events or postoperative death [MACE+POD]) after arterial reconstructions (carotid stenting or endarterectomy, aortic aneurysm repair, open peripheral surgical bypasses) registered in the SVS-VQI. Multivariate mixed effects regression was performed adjusting for sex and surgery type, as well as clustering by surgeon and by hospital. RESULTS: From 2003 to 2017, complete data were available for 776 vascular surgeons who performed 124,171 arterial reconstructions (carotid n = 56,650; aortic n = 34,764; peripheral n = 32,757) registered in the SVS-VQI. Patient characteristics associated with higher odds of MACE+POD were female sex (odds ratio [OR] 1.07; 95% confidence interval [CI], 1.03-1.12; P = .006) and advancing age (OR, 1.04; 95% CI, 1.03-1.04; P < .001). Of the 776 surgeons, 149 (17%) had failed at least one VSB-ABS examination (group F). The unadjusted primary composite outcome of MACE+POD was marginally higher after operations performed by surgeons who never failed an examination (group P; 7% vs 6%; P = .03). This difference seems to be driven by higher rates of postoperative congestive heart failure in the aortic and lower extremity bypass cohorts as well as more postoperative myocardial infarctions after lower extremity bypass by group P surgeons. Following multivariable analyses, examination pass status was not associated with MACE+POD (OR, 0.98; 95% CI, 0.89-1.50; P = .517). However, increasing surgical experience correlated with significantly lower odds of MACE+POD (2% lower odds/year of experience since training [OR, 0.98; 95% CI, 0.98-0.99; P < .001]). CONCLUSIONS: VSB-ABS examination performance by SVS-VQI surgeons does not correlate with registry-reported mortality or cardiovascular complications. Increasing surgical experience is strongly associated with lower odds of cardiovascular morbidity and death.

Drain placement confers no benefit after carotid endarterectomy in the Vascular Quality Initiative.

OBJECTIVE: Whereas bleeding complications requiring a return to the operating room (OR) after carotid endarterectomy (CEA) are infrequent (1%), they are associated with an increased 30-day combined postoperative stroke or death rate. Drain placement after CEA varies among vascular surgeons, and there are limited data to support the practice. The goal of this study was to evaluate factors leading to drain placement and the effect of drains on postoperative outcomes including return to OR for bleeding, stroke, and death. METHODS: There were 47,752 patients identified undergoing CEA using the Vascular Quality Initiative registry from 2011 to 2015. Demographic, preoperative, and intraoperative factors between patients who underwent CEA with (n = 19,425) and without (n = 28,327) drain placement were compared. End points included return to the OR for bleeding, stroke, death, postoperative wound infection, and hospital length of stay. We then compared postoperative outcomes between groups using mixed effect logistic regression models to control for correlation within center. Similar methods were used to show relationship between return to OR for bleeding and other variables. Subgroup analysis of patients with drain placement was compared among centers with high (>66.7% of cases), medium (33.3%-66.7%), and low (<33.3%) use. RESULTS: Patients with drain placement were more likely to be taking a preoperative P2Y12 antagonist (P < .001), to have prior CEA or carotid artery stenting (P < .001), to use dextran (P < .001), and to have a concomitant procedure or coronary artery bypass graft (P < .001) and less likely to use protamine (P < .001) compared with those without drain placement. Drain placement did not prevent return to the OR for bleeding (P < .22). Re-exploration of the carotid artery after closure in the OR (P < .001), preoperative P2Y12 antagonist use (P < .001), and no protamine use (P < .001) were predictors for return to the OR for bleeding among those with drain placement. Of patients requiring return to the OR for bleeding, drain placement did not influence 30-day stroke (P = .82), 30-day mortality (P = .43), or 30-day combined stroke/mortality (P = .42) compared with those without drain placement. Drain placement did not influence postoperative wound infection (P < .3). Hospital length of stay was increased in patients with drain placement (P < .001). Return to the OR for bleeding (P = .24), wound infection (P = .16), and length of stay (P = .94) did not differ between the groups of high, medium, and low drain use. CONCLUSIONS: Drain placement after CEA does not reduce return to the OR for bleeding, nor does it reduce perioperative stroke or death. Drain placement is associated with increased length of stay.

Concomitant ipsilateral carotid endarterectomy and stenting is an effective treatment for tandem carotid artery lesions.

OBJECTIVE: Data regarding the treatment of tandem carotid artery lesions at the bifurcation and ipsilateral, proximal common carotid artery (CCA) are limited. It has been suggested that concomitant treatment with carotid endarterectomy (CEA) and proximal ipsilateral carotid artery stenting confers a high risk of stroke and death. The objective of this study was to evaluate the technique and outcomes of this hybrid procedure at a single institution. METHODS: A retrospective chart review was performed including patients who underwent CEA + ipsilateral carotid artery stenting for treatment of atherosclerotic carotid artery disease between December 2007 and April 2017. Primary endpoints were postoperative myocardial infarction, neurologic event, and perioperative mortality. RESULTS: Twenty-two patients (15 male [68%]) underwent CEA + ipsilateral carotid artery stenting with a mean follow-up of 67 ± 77 months. The mean age was 70.0 ± 6.1 years old, all with a prior smoking history (eight current smokers [64%]). Twelve patients (55%) were treated for symptomatic disease and three had a prior ipsilateral CEA (one also with CAS). Computed tomographic angiography imaging was performed preoperatively in 21 patients (95%). CEA was performed first in 18 patients (82%) followed by ipsilateral carotid artery stenting. CEA was performed with a patch in 20 and eversion endarterectomy in two patients. Ipsilateral CCA was stented in 21 patients (96%) and one innominate was stented in a patient with a right CEA. Additional endovascular interventions were performed in three patients: 1 innominate stent, 1 distal ipsilateral internal carotid artery stent, and 1 right subclavian artery stent. All proximal stents were placed with sheath access through the endarterectomy patch in 12 (55%), CCA in 7 (32%), and through the arteriotomy before patching in 3 (14%). Distal internal carotid artery clamping was performed in 18 (90%, available 20) of patients before ipsilateral carotid artery stenting. All proximal lesions were successfully treated endovascularly with no open conversion. One dissection was created and treated effectively with stenting. One perioperative stroke (4.5%) occurred in a patient treated for symptomatic disease, 1 postoperative myocardial infarction (4.5%), and 2 patients (9.1%) with cranial nerve injuries. There was one patient who expired within 30 days, shortly after discharge for unknown reasons. The mean length of stay was 2.6 ± 2.0 days. CONCLUSIONS: In appropriately selected patients, concomitant CEA and ipsilateral carotid artery stenting can be safely performed in high-risk patients with a low risk of myocardial infarction, neurologic events, and perioperative mortality when careful surgical technique is used, using direct carotid access, and distal carotid clamping for cerebral protection before stenting.