Surgery or Endovascular Therapy for Chronic Limb-Threatening Ischemia.

Chronic limb-threatening ischemia is defined as ischemic rest pain or tissue loss (eg, ulceration/gangrene) that has been present for greater than 2 weeks. Workup includes a careful history, physical examination focused on evaluation of pulses and wounds, lower extremity noninvasive vascular studies (eg, ankle-brachial indices, toe pressures), saphenous vein mapping, and imaging of the lower extremity arterial anatomy (eg, computed tomography, magnetic resonance, or subtraction angiography) if a revascularization intervention is planned.

Endograft Collapse after Standard Endovascular Aneurysm Repair Implantation: A Report of Two Cases.

Endovascular aneurysm repair (EVAR) has emerged as the preferred treatment for abdominal aortic aneurysm (AAA), offering advantages such as reduced mortality, faster recovery, and fewer complications compared to open repair (OR). However, concerns persist regarding long-term durability, and the need for reinterventions. Among all reported EVAR complications, endograft collapse poses a significant challenge, particularly when presenting with acute lower limb ischemia (ALI). The aim of this report is to describe two cases of non-dissection-related abdominal endograft collapse manifesting as ALI, requiring urgent intervention, emergent conversion to OR and complete endograft removal.

Surgical Interventions for Acute Limb Ischaemia (ALI).

OBJECTIVE: To evaluate presentations, aetiologies, interventions, and outcomes of patients presenting with acute limb ischaemia (ALI). STUDY DESIGN: An observational study. Place and Duration of the Study: Department of Surgery, The Aga Khan University Hospital, Karachi, Pakistan, from January 2000 to December 2020. METHODOLOGY: Record of 104 patients who underwent surgical interventions for ALI was retrospectively evaluated. The diagnosis was confirmed on imaging (ultrasound / CTA / conventional angiography). Demographic characteristics, co-morbidities, aetiologies, and outcomes were analysed using descriptive statistics and logistic regression. RESULTS: The cohort's mean age was 58.89 ± 12.6 years, with (54.8%, n = 57) females and (45.2%, n = 47) males. Hypertension (54.8%, n = 57), diabetes (46.2%, n = 48), and atrial fibrillation (34.6%, n = 36) were common comorbidities. Thromboembolism (67.3%, n = 70) and thrombotic occlusion (32.7%, n = 34) were primary aetiologies, predominantly affecting the lower limb (66.3%, n = 58) and femoral artery (51.9%, n = 54). The majority of cases were classified as Rutherford classification 2A (53.8%; 56 cases) and 2B (44.2%; 46 cases); 58 (55.8%) patients were classified as ASA Class III, while 36 (34.6%) patients were categorised as ASA Class IV. Embolectomy (80.8%, n = 84) was the prevailing intervention, with an amputation rate (17.3%, n = 18) and a mortality rate (5.8%, n = 6). CONCLUSION: Most patients with ALI presented with Rutherford Class II and had thromboembolism aetiology. Embolectomy was the most commonly performed procedure with a high amputation rate and mortality. KEY WORDS: Acute limb ischaemia, Embolectomy, Amputation, Thromboembolism.

Controlled Reversible Visceral Arterial Ischemia, Venous Congestion and Combined Malperfusion via Midline Laparotomy in Rats.

Besides sepsis and malignancy, malperfusion is the third leading cause of tissue degradation and a major pathomechanism for various medical and surgical conditions. Despite significant developments such as bypass surgery, endovascular procedures, extracorporeal membrane oxygenation, and artificial blood substitutes, tissue malperfusion, especially of visceral organs, remains a pressing issue in patient care. The demand for further research on biomedical processes and possible interventions is high. Valid biological models are of utmost importance in enabling this kind of research. Due to the multifactorial aspects of tissue perfusion research, which include not only cell biology but also vascular microanatomy and rheology, an appropriate model requires a degree of biological complexity that only an animal model can provide, rendering rodents the obvious model of choice. Tissue malperfusion can be differentiated into three distinct conditions: (1) isolated arterial ischemia, (2) isolated venous congestion, and (3) combined malperfusion. This article presents a detailed step-by-step protocol for the controlled and reversible induction of these three types of visceral malperfusion via midline laparotomy and clamping of the abdominal aorta and caval vein in rats, underscoring the significance of precise surgical methodology to guarantee uniform and dependable results. Prime examples of possible applications of this model include the development and validation of innovative intraoperative imaging modalities, such as Hyperspectral Imaging (HSI), to objectively visualize and differentiate malperfusion of gastrointestinal, gynecological, and urological organs.

Recurrent Acute Limb Ischemia and Successful Treatment with Endovascular Thrombectomy.

Atrial fibrillation (AF) is associated with an increased risk of thromboembolic events; however, many patients with AF are noncompliant with medication regimens, which increases said risk substantially. Suboptimal health literacy presents significant hurdles to compliance with medical treatment. Here we present a case of an elderly Hispanic woman with AF and several comorbidities, including a history of dementia, who presented with consecutive recurrence of acute limb ischemia in the bilateral lower extremities just 3 days apart. Both events were successfully treated with endovascular thrombectomy. This case study not only showcases the efficacy of the latest endovascular technologies, but also draws attention to the importance of strict patient medication adherence in AF and the effects that health literacy can have on said adherence.

Free Flap Perfusion in Microvascular Head and Neck Reconstruction: Influence of the Number of Ischemia Intervals and Ischemia Duration-A Retrospective Study.

BACKGROUND: In microvascular head and neck reconstruction, ischemia of the free flap tissue is inevitable during microsurgical anastomosis and may affect microvascular free flap perfusion, which is a prerequisite for flap viability and a parameter commonly used for flap monitoring. The aim of this study was to investigate the influence of the number of ischemia intervals and ischemia duration on flap perfusion. METHODS: Intraoperative and postoperative flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation at 2 and 8 mm tissue depths, as measured with the O2C tissue oxygen analysis system, were retrospectively analyzed for 330 patients who underwent microvascular head and neck reconstruction between 2011 and 2020. Perfusion values were compared between patients without (control patients) and with a second ischemia interval (early or late) and examined with regard to ischemia duration. RESULTS: Intraoperative and postoperative flap blood flow at 8 mm tissue depth were lower in patients with early second ischemia intervals than in control patients [102.0 arbitrary units (AU) vs 122.0 AU, P = .030; 107.0 AU vs 128.0 AU, P = .023]. Both differences persisted in multivariable analysis. Intraoperative and postoperative flap blood flow at 8 mm tissue depth correlated weakly negatively with ischemia duration in control patients (r = -.145, P = .020; r = -.124, P = .048). Both associations did not persist in multivariable analysis. CONCLUSIONS: The observed decrease in microvascular flap blood flow after early second ischemia intervals may reflect ischemia-related vascular flap tissue damage and should be considered as a confounding variable in flap perfusion monitoring.

Clinical outcomes of the Burnett "snake" maneuver shunt modification for ischemic priapism.

BACKGROUND: Major ischemic priapism (IP) is defined as a persistent penile erection for >4 hours. IP may cause serious complications, especially if prompt resolution is not achieved. Therefore, selecting the most effective and usable shunt technique is crucial in IP cases that are refractory to medical therapy. AIM: To compare the effectiveness and complication risks of distal corporoglanular shunt procedures with and without the Burnett "snake" maneuver. METHODS: We conducted a retrospective study of patients who presented with IP and underwent surgical treatment at our institution between 2005 and 2021. The patients were categorized into 2 groups: group 1 (n = 26) underwent distal shunt + Burnett snake maneuver, and group 2 (n = 56) underwent distal shunt-only. Clinical history, parameters of IP, details of medical and surgical treatments, and follow-up information were evaluated. OUTCOMES: Outcomes included differences in IP resolution and recurrence, functional erections, and complications between corporoglanular shunt procedures with and without the Burnett snake maneuver. RESULTS: In group 1, 24 of 26 patients (92.3%) experienced priapism resolution with a single surgical intervention, while this outcome was observed in 30 of 56 patients (53.6%) in group 2 (P < .001). Notably, priapism recurrence was significantly lower in group 1, occurring in 1 of 24 patients (4.2%), as opposed to 8 of 30 patients (26.6%) in group 2 (P < .001). Of the patients with documented sexual function status at follow-up, functional erections (capable of penetration with or without phosphodiesterase 5 inhibitors) were noted in 6 of 14 patients (42.8%) in group 1 and 13 of 26 patients (50%) in group 2 (P = .66). CLINICAL IMPLICATIONS: This study provides valuable insights regarding technical aspects of distal shunt procedures with and without the Burnett snake maneuver for treating major IP episodes. These results can help surgeons with clinical decision making for patients who present with IP. STRENGTH AND LIMITATIONS: Limitations include the single-site retrospective design with potential selection bias, inaccuracies in medical record data, challenges in controlling confounding variables, and the lack of validated questionnaire scores for erectile function evaluation. CONCLUSION: Our study demonstrates that modifying distal shunt procedures using the Burnett snake maneuver significantly improves priapism resolution and effectively prevents further priapism episodes without introducing additional complications or erectile function loss, thereby distinguishing it from distal shunt-only procedures.

Minimally invasive surgical approach to model hypertrophic scarring in the rabbit ear.

BACKGROUND: Current strategies for hypertrophic scar prevention and treatment are limited. OBJECTIVE: To facilitate these efforts, a minimally invasive hypertrophic scar model was created in a rabbit ear for the first time based on previous methods used to induce ischemia. METHODS: Six New Zealand white rabbits (12 ears total) were studied. First, ischemia was achieved by ligating the cranial artery, cranial vein and central artery, while preserving the caudal artery, caudal vein and central vein, respectively. The relative level of ischemia induced at time of surgery, both baseline and maximum perfusion, was assessed with a fluorescent light-assisted angiography and demonstrated lower rates of perfusion in the ischemic ears. Following vascular injury, a 2-cm full thickness linear wound was created on the ventral ear and closed with 4 - 0 Nylon sutures under high tension. For each rabbit, one ear received a combination of ischemia and wounding with suture tension (n = 6), while the other ear was non-ischemic with wounding and suture tension alone (n = 6). RESULTS: Four weeks post-operatively, ischemic ears developed scar hypertrophy (histological scar thickness: 1.1 ± 0.2 mm versus 0.5 ± 0.1 mm, p < 0.05). CONCLUSION: Herein, we describe a novel, prototypical minimally invasive rabbit ear model of hypertrophic scar formation that can allow investigation of new drugs for scar prevention.

Heparin-Induced Thrombocytopenia After Revascularization of Gustilo-Anderson Type IIIC Open Lower Leg Fracture: A Case Report of Subsequent Ischemic Limb Salvage Failure.

BACKGROUND Heparin-induced thrombocytopenia (HIT) is a disease in which the immune response elicited by heparin results in a state of hypercoagulability and platelet activation, leading to thrombocytopenia and thromboembolism. Gustilo-Anderson type IIIC open fractures of the extremities are defined as open fractures presenting with arterial injuries that require repair and result in treatment challenges and complications. The diagnosis of HIT can be difficult in patients with severe trauma with consumptive thrombocytopenia associated with heavy bleeding and the use of heparin after vascular anastomosis. CASE REPORT A 48-year-old man was injured in a car accident, pinching his right lower leg and sustaining a Gustilo-Anderson type IIIc open fracture, for which he underwent emergency revascularization surgery. Heparin was administered continuously immediately after the surgery. On postoperative day 9, ischemic changes were observed in the right foot, and we performed suture re-anastomosis; however, the blood circulation in the right lower leg did not resume, and right lower leg amputation was performed due to ischemic necrosis with the onset of HIT. Postoperatively, the patient was switched to edoxaban after the recovery of his platelet count. Thereafter, the patient experienced no new thrombus occlusion or wound trouble, and was able to walk on a prosthetic leg and return to daily life. CONCLUSIONS It is important to consider the possibility of HIT as soon as thrombocytopenia appears in patients with Gustilo-Anderson type IIIC open fracture who are receiving heparin after vascular anastomosis, as a delayed diagnosis of HIT can make it difficult to save the limb.

Changes in the Remaining Iliac Artery According to Retrograde Flow after Aorto-Femoral Bypass in Abdominal Aortic Aneurysms.

BACKGROUND: Considering a patient's anatomy and vascular conditions, aorto-femoral bypass is a treatment approach for the open repair of abdominal aortic aneurysms. This study aimed at evaluating changes in the remnant iliac artery and their correlation with the preservation state of retrograde flow from femoral anastomosis. METHODS: Of 221 patients who underwent abdominal aortic aneurysm surgery between 2007 and 2022 in Pusan National University Hospital, 29 patients who underwent aorto-femoral bypass were included in this retrospective cohort study. Of these patients, 21 underwent aortobifemoral bypass and 8 underwent aortoiliac-and-femoral bypass. The change in size of the iliac artery from preoperative to postoperative and whether this difference in size depended on the status of postoperative retrograde flow were investigated. Additionally, factors affecting overall mortality and ischemic complications were identified. RESULTS: The median duration from operation to the last follow-up was 2069.5 days (about 5.7 years). The average age of the patients was 78.1 years, and the proportion of males was 75.9%. In cases of disappearance of postoperative retrograde flow from the femoral anastomosis, the postoperative iliac artery size was significantly reduced compared to its preoperative size (18.4 ± 18.9 mm vs. 13.2 ± 7.9 mm, respectively; P = 0.04). The group with maintained retrograde flow had significantly larger residual common iliac artery size than the group with disappearance of flow. (20.0 ± 28.0 mm vs. 14.6 ± 8.5 mm, respectively; P = 0.02). Disappearance of retrograde flow was a significant factor in the iliac artery size reduction after surgery (odds ratio, 2.5; 95% confidence interval, 1.9-5.3; P = 0.02). Three patients with maintained retrograde flow (18.8%) required intervention owing to an increase in the size of the iliac artery. The factors that significantly influenced overall death as analyzed by Cox proportional hazard regression were chronic obstructive pulmonary disease (hazard ratio, 36.8; 95% confidence interval, 1.6-870.0; P = 0.03), peripheral arterial occlusive disease (hazard ratio, 12.7; 95% confidence interval, 1.4-115.8; P = 0.02), and disappearance of retrograde flow (hazard ratio, 8.7; 95% confidence interval, 1.2-63.9; P = 0.03). CONCLUSIONS: Among the open repair methods for abdominal aortic aneurysms, if retrograde flow was not maintained through femoral anastomosis when aorto-femoral bypass was performed, the size of the remaining iliac artery decreased. However, loss of retrograde flow increased long-term mortality. When aorto-femoral bypass is performed, regular imaging follow-up is necessary at appropriate intervals to check the remnant iliac artery and retrograde flow.

Staged treatment with arterial reconstruction and flap transplantation for ischemic mangled extremity: An observational study.

Patients with traumatic ischemic mangled extremities first undergo arterial reconstruction using autogenous vein grafts, followed by flap transplantation as a staged treatment for soft tissue reconstruction. This study aimed to report the outcomes of such a staged treatment. Thirteen patients underwent arterial reconstruction between February 2015 and April 2017 due to damage to the major blood vessels by the traumatic mangled extremities. Of them, 6 patients (5 males and 1 female with a mean age of 51 years, age range: 36-60 years) who underwent soft tissue reconstruction due to necrosis were retrospectively analyzed. The average Mangled Extremity Severity Score was 7.2 (range, 6-8). Injuries were found in the lower leg (4 cases), foot (1 case), and wrist and hand (1 case). Arterial reconstruction was performed using autologous venous grafts. The reconstructed arteries included the posterior tibial artery (3 cases), anterior tibial artery (1 case), dorsalis pedis artery (1 case), and radial artery (1 case). The blood circulation status of the reconstructed blood vessels was assessed using computed tomography angiography at an average of 5 weeks (range, 4-6 weeks) after arterial reconstruction. For some necrotic soft tissues, debridement and flap transplantation were performed an average of 7 weeks (range, 6-8 weeks) after arterial reconstruction. Soft tissue reconstruction was performed with an anterolateral thigh free flap in 4 cases, a local flap in 1 case, and a muscle flap in 1 case. In 5 out of 6 cases, blood circulation was maintained in the reconstructed blood vessels, resulting in the salvaging of the extremities. All the patients who underwent flap surgery survived. Notably, there were no special complications during a follow-up visit conducted at an average of 19 months post-reconstruction. To treat an ischemic mangled extremity, the limbs should first be salvaged with arterial reconstruction, followed by subsequent appropriate flap surgery when soft tissue necrosis occurs at the mangled site as a staged treatment.

Alternative vein bypass in octogenarians with chronic limb-threatening ischaemia.

BACKGROUND: Octogenarians are regarded as one of the frailest patient groups among the chronic limb-threatening ischaemia population with high perioperative morbidity and mortality rates. As a result, alternative vein bypass surgery in the absence of sufficient great saphenous vein is often not considered as a potential treatment option. The aim of this study was to compare the results of octogenarians undergoing alternative vein bypass surgery due to chronic limb-threatening ischaemia to younger patients. METHODS: A single-centre retrospective analysis of patients undergoing bypass surgery for chronic limb-threatening ischaemia with alternative autologous vein grafts between 1997 and 2018 was performed. Patients aged over 80 years were compared with those under 80 years. Graft patency rates were assessed and a risk factor analysis for limb loss was performed. RESULTS: In total, 592 patients underwent bypass surgery during the study interval. Twenty-one per cent (n = 126) of patients were 80 years or older. At 4 years, primary, primary-assisted and secondary patency as well as limb salvage rates were not significantly different between the two groups (46% versus 50%, 60% versus 66%, 69% versus 72%, 72% versus 77%, for octogenarians versus non-octogenarians respectively). Major amputations were performed in 27 (21%) octogenarians and 91 (20%) non-octogenarians (P = 0.190). No higher 30-day and long-term mortality rates nor morbidity rates were detected in the octogenarian group with a median follow-up time of 27 (interquartile range 12-56) months. Minor amputation, the reason for alternative vein grafts, as well as the profunda femoris artery as proximal origin of the bypass were risk factors for limb loss in the postoperative course. CONCLUSION: Alternative vein bypass surgery in octogenarians with chronic limb-threatening ischaemia is safe and effective in terms of patency rates, limb salvage and survival compared with younger patients in the absence of sufficient great saphenous vein. Age alone should not be a deterrent from performing bypass surgery.

Development of an Education Material Targeting Patients Undergoing Lower Extremity Amputation due to Severe Limb Ischemia-A Qualitative Study.

INTRODUCTION: Critical limb-threatening ischemia (CLTI) is associated with a high risk of amputation, yet patients undergoing amputation due to CLTI have little knowledge of the amputation process and the rehabilitation that awaits. The aim of the present study was to develop and validate information material for patients undergoing amputation. METHODS: Nine participants were included in the study. Two focus group interviews were performed with seven patients who had undergone lower extremity amputation due to CLTI within the past 2 y. Additionally, two individual interviews were carried out. A semistructured interview guide was used, and the interviews were transcribed verbatim and analysed using qualitative content analysis with a deductive approach. RESULTS: Three themes were identified as essential for the design of the written information: Perspectives on design and formatting, Providing information to enhance participation in care, and Accessibility to information and support. The prototyped information leaflet was perceived as acceptable, useable, relevant, and comprehensible by the participants. CONCLUSIONS: For patients to actively engage in their care, it is vital that their information needs are met and that they are provided with psychosocial support when needed. Written and oral information should be provided by a trusted healthcare professional.

Enhanced external counterpulsation treatment improves multi-organ hemodynamics for postoperative liver transplantation patient. A case report.

INTRODUCTION: Post liver transplantation (LT) patients endure high morbidity rate of multi-organ ischemic symptoms following reperfusion. We hypothesize that enhanced external counterpulsation (EECP) as a typical non-invasive assisted circulation procedure, which can efficiently inhibit the relative ischemic symptoms via the systemic improvement of hemodynamics. CASE PRESENTATION: A 51-year-old male patient, 76 kg, 172 cm, received orthotopic LT surgery for viral hepatitis B induced acute-on-chronic liver failure hepatic failure. His medical records revealed ischemic symptoms in multi-organ at the time of hospital discharge, including headache, refractory insomnia, abdominal paralysis, and lower limb pain. The EECP treatment was introduced for assisted rehabilitation and to improve the postoperative quality of life. Doppler Ultrasound examination showed significant augmentation of blood flow volume in the carotid arteries, the hepatic artery, the portal vein and the femoral artery during EECP intervention. A standard 35-hour EECP treatment led to significant improvement in quality of life, e.g. sleep quality and walking ability. CONCLUSION: We report a case of multi-organ ischemic symptoms in a post LT patient. EECP treatment can significantly improve the quality of life via the systematic promotion of hemodynamics.

Development of the AMPDECIDE Decision Aid to Facilitate Shared Decision Making in Patients Facing Amputation Secondary to Chronic Limb Threatening Ischemia.

INTRODUCTION: We developed a patient decision aid to enhance patient participation in amputation level decision making when there is a choice between a transmetatarsal or transtibial amputation. METHODS: In accordance with International Patient Decision Aid Standards, we developed an amputation level patient decision aid for patients who are being considered for either a transmetatarsal or transtibial amputation, incorporating qualitative literature data, quantitative literature data, qualitative provider and patient interviews, expert panel input and iterative patient feedback. RESULTS: The rapid qualitative literature review and qualitative interviews identified five domains outcome priority domains important to patients facing amputation secondary to chronic limb threatening ischemia: 1) the ability to walk, 2) healing and risk for reamputation, 3) rehabilitation program intensity, 4) ease of prosthetic use, and 5) limb length after amputation. The rapid quantitative review identified only two domains with adequate evidence comparing differences in outcomes between the two amputation levels: mobility and reamputation. Patient, surgeon, rehabilitation and decision aid expert feedback allowed us to integrate critical facets of the decision including addressing the emotional context of loss of limb, fear and anxiety as an obstacle to decision making, shaping the decision in the context of remaining life years, and how to facilitate patient knowledge of value tradeoffs. CONCLUSIONS: Amputation level choice is associated with significant outcome trade-offs. The AMPDECIDE patient decision aid can facilitate acknowledgment of patient fears, enhance knowledge of amputation level outcomes, assist patients in determining their personal outcome priorities, and facilitate shared amputation level decision making.

Midterm Outcomes and Predictors of Failure of Lower Extremity Bypass to Para-Malleolar and Pedal Targets.

BACKGROUND: The frequency of distal lower extremity bypass (LEB) for infrapopliteal critical limb threatening ischemia (IP-CLTI) has significantly decreased. Our goal was to analyze the contemporary outcomes and factors associated with failure of LEB to para-malleolar and pedal targets. METHODS: We queried the Vascular Quality Initiative infrainguinal database from 2003 to 2021 to identify LEB to para-malleolar or pedal/plantar targets. Primary outcomes were graft patency, major adverse limb events [vascular reintervention, above ankle amputation] (MALE), and amputation-free survival at 2 years. Standard statistical methods were utilized. RESULTS: We identified 2331 LEB procedures (1,265 anterior tibial at ankle/dorsalis pedis, 783 posterior tibial at ankle, 283 tarsal/plantar). The prevalence of LEB bypasses to distal targets has significantly decreased from 13.37% of all LEB procedures in 2003-3.51% in 2021 (P < 0.001). The majority of cases presented with tissue loss (81.25. Common postoperative complications included major adverse cardiac events (8.9%) and surgical site infections (3.6%). Major amputations occurred in 16.8% of patients at 1 year. Postoperative mortality at 1 year was 10%. On unadjusted Kaplan-Meier survival analysis at 2 years, primary patency was 50.56% ± 3.6%, MALE was 63.49% ± 3.27%, and amputation-free survival was 71.71% ± 0.98%. In adjusted analyses [adjusted for comorbidities, indication, conduit type, urgency, prior vascular interventions, graft inflow vessel (femoral/popliteal), concomitant inflow procedures, surgeon and center volume] conduits other than great saphenous vein (P < 0.001) were associated with loss of primary patency and increased MALE. High center volume (>5 procedures/year) was associated with improved primary patency (P = 0.015), and lower MALE (P = 0.021) at 2 years. CONCLUSIONS: Despite decreased utilization, open surgical bypass to distal targets at the ankle remains a viable option for treatment of IP-CLTI with acceptable patency and amputation-free survival rates at 2 years. Bypasses to distal targets should be performed at high volume centers to optimize graft patency and limb salvage and minimize reinterventions.

Influence of a Novel Morphology-Driven Classification on Limb Salvage after Isolated Tibial Intervention for Chronic Limb Threatening Ischemia.

BACKGROUND: Infra-popliteal interventions for chronic limb-threatening ischemia (CLTI) can be impacted by the morphology of the tibial vessels. The aim of this study was to examine the impact of a novel morphology-driven classification on the outcomes of isolated tibial intervention for CLTI. METHODS: A database of patients undergoing isolated tibial interventions for CLTI at a single center between 2010 and 2020 was retrospectively queried. Patients with isolated infra-popliteal disease were identified, and their anatomy was scored as present or absent for lesion calcification (1 point), target vessel diameter<3.0 mm (1 point), lesion length>300 mm (1 point), and poor pedal runoff score (1 point). Patients were then divided into 3 groups: low risk (0 or 1 points), moderate risk (2 points), and high risk (3 or 4 points). Intention to treat analysis by the patient was performed. Limb-based patency (the absence of reintervention, occlusion, critical stenosis [>70%], or hemodynamic compromise with ongoing symptoms of CLTI as it related to the patency of the preoperatively determined target artery pathway) was assessed. Patient-oriented outcomes of amputation-free survival (AFS; survival without major amputation) and freedom from major adverse limb events (MALE; above ankle amputation of the index limb or major reintervention: new bypass graft, jump/interposition graft revision) were evaluated. RESULTS: 1,607 patients (55% male, average age 60 years, 3,846 vessels) underwent tibial intervention for CLTI. The majority of the patients were diabetic and of Hispanic origin. Morphologically, 27%, 31%, and 42% of the vessels were categorized as low risk, moderate risk, and high risk, respectively. There was a significant worsening of the infra-popliteal Global Limb Anatomic Staging System (GLASS) grading as the morphological risk increased. The 30-day major adverse cardiac events (MACE) were equivalent across the groups and were under the stated objective performance goal (OPG) of ≤10%. In contrast, both the 30-day MALE and the 30-day major amputations were significantly different across the groups, with the low-risk group remaining under the OPG of ≤9% and ≤4%, respectively, while the moderate risk and high risk exceeded the goal threshold. For the OPG, freedom from MALE was 60 ± 5%, 46 ± 5%, and 22 ± 9% at 5 years for low-, moderate-, and high-risk groups, respectively (mean ± standard error of the mean; P = 0.008). Overall AFS was 55 ± 5%, 37 ± 6%, and 18 ± 7% at 5 years for low-, moderate-, and high-risk groups, respectively (mean ± standard error of the mean; P = 0.003). CONCLUSIONS: Tibial anatomic morphology impacts isolated tibial endovascular intervention with adverse morphology associated with poorer short- and long-term outcomes. Risk stratification based on anatomic predictors should be an additional consideration as one intervenes on infra-popliteal vessels for CLTI.

Intraoperative Transit-Time Flow as a Predictor of Failure after Infrainguinal Revascularization with Heparin-Bonded Expanded Polytetrafluoroethylene Graft.

BACKGROUND: The heparin-bonded expanded polytetrafluoroethylene (He-ePTFE) conduit is an option for patients requiring infrainguinal revascularization (iIR), but the risk of failure may be unpredictable, especially in cases with poor run-off. Intraoperative transit-time flow (TTF) provides an automated and quantitative analysis of flow and may serve as an adjunct evaluation during surgical revascularization. The aim of this study was to assess TTF in patients undergoing iIR with He-PTFE at 3 referral hospitals and to establish a predictive flow threshold for graft occlusion. METHODS: A prospective registry initiated in 2020 enrolled patients undergoing iIR using He-PTFE for critical limb ischemia or severe claudication, and TTF measurement was analyzed. Preoperative assessments of anatomical and clinical characteristics were available for all patients. The HT353 Optima Meter (Transonic Systems Inc., Ithaca, NY, USA) was used in all procedures according to a standardized protocol. The institutional ethics committee approved the study. A predictive model using receiver operating characteristic curve analysis was utilized to establish the threshold of flow, and variables were compared. Anatomical and clinical evaluation were reported according to Rutherford grade, Global Limb Anatomic System and Wound, Ischemia, and foot Infection classification. The main outcome considered was the correlation between TTF and graft occlusion. Secondary outcomes included survival, other predictors of graft occlusion, freedom from major adverse cardiovascular events, and freedom from major amputation. RESULTS: Among 68 patients, 55.8% had Rutherford 5-6, 45.6% had Global Limb Anatomic System 3 and 73.5% had Wound, Ischemia, and foot Infection 3-4. Distal anastomosis was at tibial level in 23.5% and mean diameter of conduit was 6.4 mm. Basal and postoperative TTF were 27.8 ± 15.6 ml/min and 109.0 ± 53.0 ml/min, respectively. After a mean follow-up of 18 ± 13 months, 7 (10.9%) patients presented graft occlusion and 5 (7.8%) required major amputation. TTF threshold = 80 ml/min revealed a sensitivity and specificity of 81.8% (95% confidence interval 48.2-97.7) and 80.7% (95% confidence interval 68.1-90.0) respectively, and it was selected as cut-off for graft occlusion. Freedom from graft occlusion in patients with TTF >80 ml/min vs. TTF ≤80 ml/min at 6, 12, and 24 months was 95.7% (standard error (SE) = 0.030) vs. 65.5% (SE = 0.115), 95.7% (SE = 0.030) vs. 58.9% (SE = 0.120) and 90.9% (SE = 0.054) vs. 51.6% (SE = 0.126), P = 0.0003. No statistical difference in primary patency, secondary patency and limb salvage was observed. At multivariate analysis, distal anastomosis at tibial vessel (odds ratio 8.50) and TTF ≤80 ml/min (odds ratio 9.39) were independent predictors of graft occlusion. CONCLUSIONS: These results suggest that TTF may serve as a valuable tool in the management of iIR. A TTF measurement of ≤80 ml/min should be regarded as a predictor of graft occlusion, prompting consideration of additional intraoperative maneuvers to enhance arterial flow. Caution should be exercised in patients requiring direct tibial artery revascularization, as it represents a predictor of failure independent of TTF levels. Larger cohorts of patients and longer follow-up periods are necessary to confirm these findings.