A systematic review and meta-analysis of revascularization outcomes of infrainguinal chronic limb-threatening ischemia

Meta-Analysis of Randomised Controlled Trials Comparing Bypass and Endovascular Revascularisation for Peripheral Artery Disease

OBJECTIVE

Peripheral artery disease affects approximately 250 million people globally. Multiple randomised controlled trials have compared bypass and endovascular interventions but the optimum revascularisation approach remains unclear. The recently published BEST-CLI and BASIL-2 trials provide current and robust data addressing this question, however their findings are not concordant. This systematic review and meta-analysis provides an overview of the worldwide randomised evidence comparing bypass surgery and endovascular revascularisation in lower limb peripheral artery disease.

METHODS

A comprehensive literature search of MEDLINE, Embase and CENTRAL databases was performed of all time periods up to 7 May 2023 to identify randomised controlled trials comparing bypass and endovascular revascularisation for treating lower limb peripheral artery disease. The primary outcome was major amputation. Secondary outcomes were mortality, re-intervention, 30-day adverse events and 30-day mortality. Odds ratios were calculated and pooled using the random-effects model. Risk of bias was assessed using the Cochrane risk of bias 2 tool.

RESULTS

Fourteen cohorts were identified across thirteen studies, enrolling 3840 patients. There was no significant difference in major amputation (OR 1.12; 95% CI 0.80-1.57) or mortality (OR 0.96; 95% CI 0.79-1.17) between the bypass and endovascular groups. Bypass was associated with a significant reduction in re-intervention compared with endovascular treatment (OR 0.57, 95% CI 0.40-0.82).

CONCLUSIONS

These findings suggest that rates of major amputation and mortality are similar following bypass and endovascular interventions. Patients who undergo bypass surgery have a significantly lower re-intervention rate post-operatively.

Comparing the efficacy and safety of endovascular therapy versus surgical revascularization for critical limb-threatening ischemia: A systematic review and Meta-analysis

INTRODUCTION

Critical limb-threatening ischemia (CLTI) is a severe manifestation of peripheral artery disease (PAD) that can lead to limb amputation and significantly reduce quality of life. In addition to guideline-directed medical therapy (GDMT), endovascular therapy and surgical revascularization are the two revascularization options for CLTI. In recent years, there has been an ongoing debate about the best approach for CLTI patients. The purpose of this meta-analysis is to examine the current evidence and compare the clinical outcomes of endovascular therapy and surgical revascularization for CLTI.

METHODS

We conducted a systematic search of electronic databases (PubMed, Embase, Cochrane Library, and Web of Science) for studies comparing the outcomes of endovascular therapy versus surgery in patients with CLTI. The primary outcomes were major adverse limb events (MALE) and major adverse cardiovascular events (MACE), while secondary outcomes included risk of bleeding, wound complications, readmission, unplanned reoperation, acute renal failure, and length of hospital stay. Pooled data was analyzed using the fixed-effect model or the random-effect model in Review Manager 5.3. The Newcastle-Ottawa Scale and Cochrane risk of bias assessment tool were used to assess the bias of included studies.

RESULTS

A total of 16 studies (47,609 patients) were included in this meta-analysis. The overall effect favors surgery over endovascular intervention in terms of MALE [odds ratio (OR) 1.13, 95% CI (1.01-1.28), P = 0.04]. Endovascular therapy is associated with lower MACE rates compared to surgery [OR 0.62, 95% CI (0.51-0.76), P < 0.00001]. Furthermore, the risk of bleeding, wound complications, readmission, unplanned reoperation, acute renal failure as well as the length of hospital stay was lower for endovascular intervention. Finally, there was no statistically significant difference in 30-day mortality between the two groups [OR 0.94, 95% CI 0.79-1.12, P = 0.52; Fig. 3i], and the pooled studies were homogeneous [P = 0.39; I2 = 5%].

CONCLUSION

Surgery may be the preferred treatment option for CLTI patients, as it is associated with a lower risk of MALE than endovascular therapy. However, endovascular therapy may be associated with a lower risk of MACE and lower rates of bleeding, wound complications, readmission, unplanned reoperation, acute renal failure, and shorter hospital stays. There was no statistically significant difference in 30-day mortality between the two groups. Ultimately, the decision to use endovascular therapy or surgery as the primary treatment strategy should be based on a multi-disciplinary team approach with careful consideration of patient characteristics and anatomy.

Learning curve in tibial and pedal bypass with autologous vein graft

OBJECTIVES

The 2019 Global Vascular Guidelines recommended open bypass for patients at average risk with greater limb severity and anatomical complexity. However, the outcomes of tibial and pedal bypass (TPB) are inferior to those of above-the-knee surgical revascularization. This may be due to the technical difficulty and need for development of skills to perform TPB. However, there is a limited knowledge on the learning curve in TPB. Thus, the aim of the study is to assess this learning curve in a single-center retrospective analysis.

METHODS

Cases treated with TPB with an autologous vein conduit in patients with chronic limb-threatening ischemia (CLTI) at a Japanese single center from 2009 to 2022 were analyzed retrospectively. The primary endpoint was the learning curve for TPB.

RESULTS

The study included 449 TPB procedures conducted by a single main surgeon in patients with CLTI (median age, 75 years; 309 males; diabetes mellitus, 73%; end stage renal failure with hemodialysis, 44%). The operative time decreased significantly as the number of cases accumulated (p < .001). Using the cumulative sum (CUSUM) operative time, the learning curve was estimated to be phase 1 (initial learning curve) for 134 cases (1-134); phase 2 (competent period) for 179 cases (135-313); and phase 3 (mastery and challenging period) for 136 cases (314-449). The mean follow-up period was 34 ± 31 months. The 1- and 3-year limb salvage rates of 97% and 96% in phase 3 were significantly higher than those in phases 1 and 2 (p < .001, p = .029). Major adverse limb events (MALE) occurred in 117 (26%) patients, and the 1- and 3-year MALE rates of 10% and 17% in phase 3 were significantly lower than those in phases 1 and 2 (p < .001, p = .009).

CONCLUSIONS

In the study, vascular surgeon required a learning curve of 134 TPB cases to Overcoming the learning curve for bypass was associated with improvement of medium-term outcomes for limb salvage and freedom from MALE.

Nationwide Study of the Outcome of Treatment of Lower Extremity Atherosclerotic Lesions With Endovascular Surgery With or Without Drug Eluting Methods in Patients With Diabetes

CLINICAL IMPACT

This retrospective observational registry trial combines national registries for vascular surgical procedures and diabetes mellitus to clarify results of drug eluting technology in treating diabetic subjects with intermittent claudication or chronic limb threatening ischemia compared to treatment of non-diabetic subjects. As earlier proposed and showed in this trial, there may be an implication for a beneficial treatment efficacy with drug eluting therapy in the diabetic population with PAD compared to the non-diabetic population. A finding worth further exploration.

Validation of the global limb anatomical staging system in Vietnamese patients treated for chronic limb-threatening ischemia

BACKGROUND

Chronic limb-threatening ischemia (CLTI) is the most severe clinical form of peripheral artery disease (PAD), accounting for approximately 11%, and is strongly associated with the incidence of amputation, cardiovascular events, and mortality. The Global Vascular Guideline (GVG) proposed a new Global Anatomic Staging System (GLASS) for evaluating the anatomic complexity of arterial lesions. However, more research is required to evaluate outcomes after endovascular intervention in CLTI patients using the GLASS.

OBJECTIVE

Our study aimed to describe clinical characteristics, arterial lesions, and endovascular interventions according to three grades of GLASS in the Vietnamese population. We evaluated the technical success, mortality rate, and probability to preserve the limb according to the GLASS.

METHODS

All patients were diagnosed with CLTI and underwent infrainguinal endovascular intervention at the Department of Thoracic and Vascular Surgery, University Medical Center, Ho Chi Minh City from June 2020 to June 2022. All patients were evaluated before intervention and follow-up at 6 and 12 months after intervention. Patients were divided into three groups according to the GLASS, thereby comparing the technical success, mortality, and amputation rates. This retrospective study describes a series of cases.

RESULTS

The study sample evaluated 82 lower limbs of 82 patients, in which GLASS class I, II, and III lesions accounted for 36.6%, 43.9%, and 19.5% of the patients, respectively. The rates of technical success in the groups gradually decreased according to the complexity of the lesions (90%, 86.11%, and 56.25% for GLASS I, II, and III, respectively; p = 0.012). Notably, limb-based patency (LBP) at 12 months was significantly lower in the GLASS III group than in the GLASS I and II groups (22.22% vs 88.89% and 67.74%, respectively; p = 0.001). The amputation rates at 12 months in GLASS groups I, II, and III were 13.3%, 22.2%, and 50%, respectively (p = 0.021), while the mortality rates at 12 months were 0%, 8.33%, and 25%, respectively (p = 0.015).

CONCLUSION

In patients with CLTI of higher GLASS stages, the rates of technical success were lower and the amputation and mortality rates were higher.

Surgical and Endovascular Therapies for Below-the-Knee Peripheral Arterial Disease: A Contemporary Review

Peripheral arterial disease (PAD) represents one of the most prevalent cardiovascular disease processes and carries a high burden of morbidity and mortality. Patients with chronic limb-threatening ischemia (CLTI), the most severe manifestation of PAD, have the highest rates of cardiovascular morbidity and mortality of the overall PAD population. Patients with below-the-knee (BTK) PAD have an increased propensity toward CLTI due to small-vessel caliber and the frequently comorbid conditions of end-stage renal disease and diabetes mellitus, which tend to affect small artery beds preferentially. For those with BTK PAD with CLTI, the standard of care is revascularization. Early revascularization was performed using surgical bypass. However, endovascular techniques, starting with percutaneous transluminal angioplasty and expanding to the modern armamentarium of adjunctive devices and therapies, have become standard of care for most patients with CLTI due to BTK PAD. In this review, we will discuss the modern surgical and endovascular approaches to revascularization, as well as devices that are currently in development or preapproval study for the treatment of BTK PAD.

Role of toll-like receptor 4 in skeletal muscle damage in chronic limb-threatening ischemia

Objective

Toll-like receptors (TLRs) are key pattern recognition receptors in the innate immune system. In particular, the TLR4-mediated immune response has been implicated in ischemia-induced tissue injury. Mounting evidence supports a detrimental role of the innate immune system in the pathophysiology of skeletal muscle damage in patients with chronic limb-threatening ischemia (CLTI), in whom patient-oriented functional outcomes are poor. The overall aim of this study was to investigate the potential role of TLR4 in skeletal muscle dysfunction and damage in CLTI.

Methods

The role of TLR4 in ischemic muscle was investigated by (1) studying TLR4 expression and distribution in human gastrocnemius muscle biopsies, (2) evaluating the functional consequences of TLR4 inhibition in myotubes derived from human muscle biopsies, and (3) assessing the therapeutic potential of modulating TLR4 signaling in ischemic muscle in a mouse hindlimb ischemia model.

Results

TLR4 was found to be expressed in human muscle biopsies, with significant upregulation in samples from patients with CLTI. In vitro studies using cultured human myotubes demonstrated upregulation of TLR4 in ischemia, with activation of the downstream signaling pathway. Inhibition of TLR4 before ischemia was associated with reduced ischemia-induced apoptosis. Upregulation of TLR4 also occurred in ischemia in vivo and TLR4 inhibition was associated with decreased inflammatory cell infiltration and diminished apoptosis in the ischemic limb.

Conclusions

TLR4 is upregulated and activated in ischemic skeletal muscle in patients with CLTI. Modulating TLR4 signaling in vitro and in vivo was associated with attenuation of ischemia-induced skeletal muscle damage. This strategy could be explored further for potential clinical application.

HTATIP2 regulates arteriogenic activity in monocytes from patients with limb ischemia

Use of autologous cells isolated from elderly patients with multiple comorbidities may account for the modest efficacy of cell therapy in patients with chronic limb threatening ischemia (CLTI). We aimed to determine whether proarteriogenic monocyte/macrophages (Mo/MΦs) from patients with CLTI were functionally impaired and to demonstrate the mechanisms related to any impairment. Proarteriogenic Mo/MΦs isolated from patients with CLTI were found to have an impaired capacity to promote neovascularization in vitro and in vivo compared with those isolated from healthy controls. This was associated with increased expression of human HIV-1 TAT interactive protein-2 (HTATIP2), a transcription factor known to suppress angiogenesis/arteriogenesis. Silencing HTATIP2 restored the functional capacity of CLTI Mo/MΦs, which was associated with increased expression of arteriogenic regulators Neuropilin-1 and Angiopoietin-1, and their ability to enhance angiogenic (endothelial tubule formation) and arteriogenic (smooth muscle proliferation) processes in vitro. In support of the translational relevance of our findings, silencing HTATIP2 in proarteriogenic Mo/MΦs isolated from patients with CLTI rescued their capacity to enhance limb perfusion in the ischemic hindlimb by effecting greater angiogenesis and arteriogenesis. Ex vivo modulation of HTATIP2 may offer a strategy for rescuing the functional impairment of pro-angio/arteriogenic Mo/MΦs prior to autologous delivery and increase the likelihood of clinical efficacy.

Randomized clinical Trial Comparing drug Eluting Stent Zilver PTX® Versus Bare Metal Stent Zilver Flex® for Treatment of Lesions in Femoral and Popliteal Arteries in Chronic Limb Threatening Ischemia

OBJECTIVE

Drug eluting stents (DES) might improve the results of stenting in the femoropopliteal (FP) segment, but randomized data between DES and BMS in the treatment of patients with chronic limb threatening ischemia (CLTI) is lacking. The aim of this study was to perform a randomized comparison, between DES and bare metal stent (BMS) implantation in a subgroup of CLTI patients with lesions in the superficial femoral artery (SFA) and the P1-P2 portion of the popliteal artery.

METHODS

Patients presenting with CLTI scheduled for endovascular treatment of FP lesions were randomly assigned by blinded envelopes 1:1 in a single blinded, parallel group design to DES or BMS after lesion crossing. Primary endpoints were target lesion revascularization (TLR) at 12 and 24 months and primary patency at 12 and 24 months. Secondary endpoints were technical success (TS), clinical success, secondary patency at 12 and 24 months, limb salvage, serious adverse events (SAE) at 24 month and survival at five years.

RESULTS

A total of 48 CLTI patients and 49 limbs, were enrolled, 22 in the BMS group and 27 in the DES group. Demographics, comorbidities, and Rutherford class were similar in both treatment arms. The overall rate of total occlusions was 96% and the corresponding overall median lesion length was 240 mm. No patients were lost to follow up. No significant differences were detected between groups regarding TLR and primary patency. The overall primary patency at 12 and 24 months was 42.9% and 36.7% respectively and the overall freedom from TLR was 67.3% and 61.2% respectively. The results in the two groups were also similar regarding secondary outcomes.

CONCLUSIONS

This single centre, randomized study could not demonstrate superiority of DES compared to BMS when treating long FP lesions in patients with CLTI but was limited by insufficient patient inclusion.

Three-Year Patency Results following Endovascular Transvenous Femoropopliteal Bypass

Background and Objectives: Peripheral artery disease is one of the most common vascular pathologies. There is an ongoing debate among specialists on whether open or endovascular revascularization is preferred in cases of complex superficial femoral artery (SFA) lesions. The purpose of this study was to assess patency results of a relatively new transvenous endovascular bypass device. This could add to existing evidence and aid in comparison between open and endovascular bypass. Materials and Methods: Patients with complex TASC-C and D SFA lesions who had indications for revascularization were identified. Prospective analysis of stent graft patency from 54 transvenous femoropopliteal bypass procedures was performed. Patency was assessed by Duplex ultrasound every six months. Kaplan–Meier analysis was performed to assess primary, primary-assisted, and secondary patency of transvenous bypass. Results: Following endovascular transvenous femoropopliteal bypass, 3-year graft primary, primary-assisted, and secondary patency was 43.8%, 66.3%, and 73.9%, respectively. Conclusions: Transvenous endovascular femoropopliteal bypass is a viable option for selected patients who lack adequate saphenous vein or have comorbidities that increase the risk of open femoropopliteal bypass. Strict post-operative follow-up is necessary to improve patency rates.

Quality of Life in Chronic Limb Threatening Ischaemia: Systematic Review and Meta-Analysis

OBJECTIVE

To assess the comparative effectiveness and temporal changes in quality of life (QoL) outcomes after revascularisation, major lower extremity amputation (MLEA), and conservative management (CM) in chronic limb threatening ischaemia (CLTI).

DATA SOURCES

MEDLINE, Embase, PsycINFO, CINAHL, and Web of Science.

REVIEW METHODS

A systematic review and meta-analysis were performed on QoL measured by any QoL instrument in adult patients with CLTI after open surgery (OS), endovascular intervention (EVI), MLEA, or CM. Randomised controlled trials and prospective observational studies published in any language between 1 January 1990 and 21 May 2021 were included. There was a pre-specified measurement time point of six months. Random effects meta-analysis was conducted on total scores for each QoL instrument. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach (PROSPERO registration: CRD42021253953).

RESULTS

Fifty-five studies with 8 909 patients were included. There was significant heterogeneity in the methods used to measure QoL, and the study characteristics. In particular, 14 different QoL instruments were used with various combinations of disease specific and generic instruments within each study. A narrative summary is therefore presented. Comparative effectiveness data showed there was reasonable certainty that QoL was similar between OS and EVI at six months. Temporal outcomes suggested small to moderate improvements in QOL six months after OS and EVI compared with baseline. Limited data indicated that QoL can be maintained or slightly improved after MLEA or CM. Treatment effects were overestimated owing to small study effects, selective non-reporting, attrition, and survivorship bias.

CONCLUSION

QoL after OS and EVI appears to be similar. Revascularisation may provide modest QoL benefits, while MLEA or CM can maintain QoL. However, certainty of evidence is generally low or very low, and interpretation is hampered by significant heterogeneity. There is a need for a CLTI specific QoL instrument and methodological standardisation in QoL studies.

Management of chronic peripheral artery disease patients with indication for endovascular revascularization

With an increasing global burden of patients with chronic peripheral artery disease (PAD) the safe and effective provision of lower limb revascularisation is a growing medical need. Endovascular procedures for the treatment of PAD have become a crucial cornerstone of modern vascular medicine, and the first line revascularisation approach if technically feasible and taking patient choice into consideration. With the increasing age of patients with PAD and the increasing number of comorbidities open vascular surgery is also often not feasible. We outline a framework of key messages, endorsed by the board of the European Society of Vascular Medicine for pre-, peri- and post procedural management of patients requiring endovascular arterial procedures of the lower limbs. These key messages emphasize the important and increasing role of interventional vascular physicians.

Canadian Cardiovascular Society 2022 Guidelines for Peripheral Arterial Disease

Patients with widespread atherosclerosis such as peripheral artery disease (PAD) have a high risk of cardiovascular and limb symptoms and complications, which affects their quality of life and longevity. Over the past 2 decades there have been substantial advances in diagnostics, pharmacotherapy, and interventions including endovascular and open surgical to aid in the management of PAD patients. To summarize the evidence regarding approaches to diagnosis, risk stratification, medical and intervention treatments for patients with PAD, guided by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework, evidence was synthesized, and assessed for quality, and recommendations provided-categorized as weak or strong for each prespecified research question. Fifty-six recommendations were made, with 27% (15/56) graded as strong recommendations with high-quality evidence, 14% (8/56) were designated as strong recommendations with moderate-quality evidence, and 20% (11/56) were strong recommendations with low quality of evidence. Conversely 39% (22/56) were classified as weak recommendations. For PAD patients, strong recommendations on the basis of high-quality evidence, include smoking cessation interventions, structured exercise programs for claudication, lipid-modifying therapy, antithrombotic therapy with a single antiplatelet agent or dual pathway inhibition with low-dose rivaroxaban and aspirin; treatment of hypertension with an angiotensin converting enzyme or angiotensin receptor blocker; and for those with diabetes, a sodium-glucose cotransporter 2 inhibitor should be considered. Furthermore, autogenous grafts are more effective than prosthetic grafts for surgical bypasses for claudication or chronic limb-threatening ischemia involving the popliteal or distal arteries. Other recommendations indicated that new endovascular techniques and hybrid procedures be considered in patients with favourable anatomy and patient factors, and finally, the evidence for perioperative risk stratification for PAD patients who undergo surgery remains weak.

Long-Term Outcomes of Extra-Anatomic Femoro-Tibial Bypass Reconstructions in Chronic Limb-Threating Ischemia

(1) Background: While tibial bypass surgery still plays a role in the treatment of patients with chronic limb-threatening ischemia and diabetic foot syndrome; only a few centers have recorded considerable numbers of these conditions. The current study aimed to determine contemporary practice with special focus on the performance of extra-anatomic grafting to the infrapopliteal arteries. (2) Methods: A retrospective, single-center study included patients with tibial bypass grafts from 1 January 2008 to 31 December 2019. Primary endpoints were complication rate, graft patency, amputation, overall survival, and major adverse cardiac (MACE) or limb event (MALE). The cohort was stratified by extra-anatomic vs. anatomic position. (3) Results: A total of 455 patients (31% female) with Rutherford stage 4 (12.5%) and 5/6 (69.5%) were included (thereof, 19.5% had high amputation risk according to the Wound Ischemia Foot Infection score). Autologous reconstruction was performed in 316 cases, and prosthetic reconstruction in 131 cases, with a total of 51 (11.2%) extra-anatomic grafts. Early occlusion rate was 9.0% with an in-hospital overall mortality of 2.8%. The in-hospital rate of MACE was 2.4% and of MALE, 1.5%. After one, three and five years, the primary patency of venous bypasses was 74.5%, 68.6% and 61.7%, respectively. For prosthetic grafts, this was 55.1%, 46.0%, and 38.3%, respectively (p < 0.001). The patency of extra-anatomic prosthetic grafts performed significantly better compared with anatomically positioned prosthetic grafts (log-rank p = 0.008). In multivariate analyses, diabetes (hazard ratio, HR 1.314, CI 1.023−1.688, p = 0.032), coronary artery disease (HR 1.343, CI 1.041−1.732, p = 0.023), and dialysis dependency (HR 2.678, CI 1.687−4.250, p < 0.001) were associated with lower odds of survival (4) Conclusion: In this large, single-center cohort, tibial bypass surgery demonstrated satisfactory results with overall low perioperative complication rates and long-term patency rates of 60% and 38%, respectively. Extra-anatomic bypasses represent a feasible alternative to venous grafts in terms of patency. A tailored, patient-centered approach considering predictors such as diabetes, dialysis dependency, and coronary artery disease along with prediction models may further improve the long-term results in the future.

Impact of Tibial Bypass Conduit on Long-Term Amputation-Free Survival and Primary Patency in the Vascular Quality Initiative

BACKGROUND

Much research remains focused on tibial bypass conduit selection. We sought to describe long-term amputation-free survival (AFS) and primary patency (PP) of patients undergoing tibial bypass by conduit type and configuration across several permutations in the Society for Vascular Surgery (SVS) Vascular Quality Initiative (VQI).

METHODS

Patients in the VQI registry undergoing elective first-time femoral- or popliteal-to-tibial bypass for occlusive disease involving rest pain or tissue loss were identified. Prior ipsilateral infrainguinal bypass or concomitant procedures were excluded. Outcomes of interest included patient AFS at 22 months and PP at 1 year (defined as freedom from revision, thrombectomy, or graft occlusion).

RESULTS

A total of 4,192 bypasses were identified. The majority utilized Great Saphenous Vein (GSV) (76.2%), followed by polytetrafluoroethylene (PTFE) (10.6%), non-autologous biologic (NABC) (6.5%), composite (3.3%), arm vein (2.8%), and Small Saphenous Vein (SSV) (0.6%). Compared to all prosthetic and composite bypasses, vein grafts had the best AFS (76.4%, p<0.0001) and PP (68.1%, p=0.041). Of the single segment vein conduits, GSV bypasses had the best PP (69.1%) and arm vein the worst (60.2%). AFS and PP were similar between single segment GSV orientations. Single segment GSV bypasses exhibited better PP than multiple segment bypasses (69.1% vs 54.6%, p=0.0016). PP was significantly better for PTFE compared to NABC (68.4% vs 51.2%, p=0.0039). PP did not significantly differ between vein cuff (PWC) for prosthetic bypass compared to no vein cuff (PNC) (69.1% vs 59.7%, p=0.091). PP was not significantly different between single segment GSV and prosthetic grafts with vein cuff (69.1% vs 69.1%, p=0.51). There were no significant differences in AFS comparing arm vein, PWC, or composite grafts (67.2% vs 63.8% vs 59.3%, p=0.092), as well as in PP (60.2% vs 69.1% vs 54.8%, p=0.14).

CONCLUSIONS

Single-segment vein bypass was only marginally the most optimal conduit. Surprisingly, there may be more equipoise among conduit types, particularly in the absence of adequate GSV. Prosthetic grafts overall may not be as disadvantaged in the long term as initially thought, especially when compared to arm vein, as PWC did not significantly differ in primary patency. Similarly, a composite conduit may not impact long-term outcomes. These data suggest that conduit choice may not impact outcomes to the degree previously thought and that other factors may have a greater impact than presumed, especially in conduit limited situations.

Risk Factors for Surgical Site Infection After Lower Limb Revascularization Surgery in Adults With Peripheral Artery Disease: Protocol for a Systematic Review and Meta-analysis

BACKGROUND

Surgical site infections (SSIs) are common, costly, and associated with increased morbidity and potential mortality after lower limb revascularization surgery (ie, arterial bypass, endarterectomy, and patch angioplasty). Identifying evidence-informed risk factors for SSI in patients undergoing these surgeries is therefore important.

OBJECTIVE

The aim of this study is to conduct a systematic review and meta-analysis of prognostic studies to identify, synthesize, and determine the certainty in the cumulative evidence associated with reported risk factors for early and delayed SSI after lower limb revascularization surgery in adults with peripheral artery disease.

METHODS

We will search MEDLINE, Embase, the seven databases in Evidence-Based Medicine Reviews, review articles identified during the search, and included article bibliographies. We will include studies of adults (aged ≥18 years) with peripheral artery disease that report odds ratios, risk ratios, or hazard ratios adjusted for the presence of other risk factors or confounding variables and relating the potential risk factor of interest to the development of SSI after lower limb revascularization surgery. We will exclude studies that did not adjust for confounding, exclusively examined certain high-risk patient cohorts, or included >20% of patients who underwent surgery for indications other than peripheral artery disease. The primary outcomes will be early (in-hospital or ≤30 days) SSI and Szilagyi grade I (cellulitis involving the wound), grade II (infection involving subcutaneous tissue), and grade III (infection involving the vascular graft) SSI. Two investigators will independently extract data and evaluate the study risk of bias using the Quality in Prognosis Studies tool. Adjusted risk factor estimates with similar definitions will be pooled using DerSimonian and Laird random-effects models. Heterogeneity will be explored using stratified meta-analyses and meta-regression. Finally, we will use the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to determine certainty in the estimates of association between reported risk factors and the development of SSI.

RESULTS

The protocol was registered in PROSPERO (International Prospective Register of Systematic Reviews). We will execute the peer-reviewed search strategy on June 30, 2021, and then complete the review of titles and abstracts and full-text articles by July 30, 2021, and September 15, 2021, respectively. We will complete the full-text study data extraction and risk of bias assessment by November 15, 2021. We anticipate that we will be able to submit the manuscript for peer review by January 30, 2022.

CONCLUSIONS

This study will identify, synthesize, and determine the certainty in the cumulative evidence associated with risk factors for early and delayed SSI after lower limb revascularization surgery in patients with peripheral artery disease. The results will be used to inform practice, clinical practice statements and guidelines, and subsequent research.

TRIAL REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews CRD42021242557; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=242557.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/28759.

Impact of Dual Antiplatelet Therapy after Lower Extremity Revascularization for Chronic Limb Threatening Ischemia (CLTI)

BACKGROUND

The optimal antiplatelet regimen after lower extremity revascularization in patients with chronic limb threatening ischemia (CLTI) is unknown since current recommendations are based on extrapolation of data from trials in coronary artery disease and stroke.

METHODS

We identified all patients undergoing an elective lower extremity revascularization for CLTI in the Vascular Quality Initiative registry discharged on a mono antiplatelet agent (MAPT) or dual antiplatelet therapy (DAPT).

RESULTS

From 2003 to 2018, 50,890 patients underwent revascularization procedures for CLTI, and were discharged on MAPT or DAPT. Of these, 33,781 patients underwent endovascular therapy (EVT) and 17,109 patients underwent open surgery (OS) procedures. The rate of major amputation at 30 days in the target limb in the EVT group was 0.3% and 0.4% in the OS group (P=.22). On Kaplan Meier analyses, patients on MAPT at discharge had a higher risk 1-year major amputation compared to DAPT after EVT but not after OS procedures. Patients on MAPT had lower overall survival and amputation free survival (AFS) at 30 days and 1 year compared to DAPT after both EVT and OS. At 1 year, the MAPT group was at higher risk for target lesion re-intervention after EVT compared to the DAPT group (15.9% vs. 13%, P= .0012). There was no significant difference in thrombosis at 1 year between MAPT and DAPT groups either after EVT (3.9% vs. 3.7%; P = .3048) or OS (3.1% vs. 3.2%; P= .2893). On cox regression analysis, DAPT was associated with improved survival but not major amputation after both EVT and OS.

CONCLUSIONS

In CLTI patients, DAPT at the time of discharge has a positive impact on AFS and overall survival after both EVT and OS as well as target lesion re-intervention after EVT. DAPT was not associated with a positive impact on major amputation after either EVT or OS.

Isolated femoral artery revascularisation with or without iliac inflow improvement - a less invasive surgical option in critical limb ischemia

Background: Isolated femoral artery revascularisation (iFAR) represents a well-established surgical method in the treatment of peripheral arterial disease (PAD) involving common femoral artery disease. Data for iFAR in multilevel PAD are inconsistent, particularly in patients with critical limb ischemia (CLI). The aim of the study was to evaluate the outcome of iFAR in CLI regarding major amputation and reintervention and to identify associated risk factors for this outcome. Patients and methods: The data used have been derived from the German Registry of Firstline Treatment in Critical Limb Ischemia (CRITISCH). A total of 1200 patients were enrolled in 27 vascular centres. This sub-analysis included patients, which were treated with iFAR with/without concomitant iliac intervention. For detection of risk factors for the combined endpoint of major amputation and/or reintervention, selection of variables for multiple regression was conducted using stepwise forward/backward selection by Akaike's information criterion. Results: 95 patients were included (mean age: 72 years ± 10.82; 64.2% male). Of those, 32 (33.7%) participants reached the combined endpoint. Risk factor analysis revealed continued tobacco use (odds ratio [OR] 2.316, confidence interval [CI] 0.832-6.674), TASC D-lesion (OR: 2.293, CI: 0.869-6.261) and previous vascular intervention in the trial leg (OR: 2.720, CI: 1.037-7.381) to be associated with reaching the combined endpoint. Conclusions: iFAR provides a reasonable, surgical option to treat CLI. Lesion length (TASC D) seems to have a negative impact on outcome. Further research is required to better define the future role of iFAR for combined femoro-popliteal lesions in CLI - best in terms of a randomised controlled trial.

Evaluation of 3D printing in planning, practicing, and training for endovascular lower extremity arterial interventions

Background

In this study, we aimed to investigate the potential role of 3D-printed physical and digital anatomical models in pre-procedural planning, practice and training in lower extremity arterial interventions.

Methods

A total of 16 patients (9 males, 7 females; mean age: 72.1±1.5 years; range, 69 to 75 years) who underwent superficial femoral artery balloon angioplasty between February 2016 and April 2019 were retrospectively reviewed for vascular access site preference and balloon sizing. Pre-procedural computed tomography volumetric images used for diagnosis were analyzed and modeled with 3D printing. Procedural and 3D-based data regarding the size of the balloon and deployment sites and the severity of the stenosis were compared.

Results

Measurements obtained from 3D models manually and segmentation images from software were similar (p>0.05). Both were smaller than the actual size of balloons used (p<0.001). Stenosis severity was similar with manual and software methods and both were significantly lower than the reported quantitative angiographic measurements (p<0.001). Vascular access site preference was changed in five (31.2%) patients, when the model was simulated by a non-sterile practice on 3D-printed physical models. The wire and catheter selection differed in eight patients, while practicing with models.

Conclusion

The planning and practicing of lower extremity arterial procedures with 3D models may reduce operator-dependent variables, avoid unnecessary interventions, reduce endothelial damage, and increase procedural success. The 3D-printed models may be used for educational purposes for medical professionals.

Lower Extremity Revascularization for Chronic Limb-Threatening Ischemia among Patients at the Extremes of Age

BACKGROUND

Patients with chronic limb-threatening ischemia (CLTI) at the extremes of age are thought to have distinct risk factor profiles and poor outcomes after lower extremity revascularization (LER). The aim of this study is to examine the relationships among age, risk factor profiles, and outcomes of LER in patients with CLTI in a large database focusing on the extreme age groups.

METHODS

Patients undergoing LER for CLTI in the Vascular Quality Initiative suprainguinal bypass, infrainguinal bypass, and peripheral vascular intervention files were reviewed through 2019. Patients were stratified into 3 groups: premature peripheral artery disease (PAD) (≤50 years old), 51-84 years old, and elderly (≥85 years old). Trends in major amputation and mortality by age group were analyzed.

RESULTS

There were 156,513 patients who underwent LER for CLTI. Of these, 9,063 (5.79%) patients had premature PAD, 131,694 (84.14%) patients were 51-84 years old, and 15,756 (10.07%) were elderly. Patients with premature PAD were more likely to have insulin-dependent diabetes, be dialysis-dependent, and be active smokers compared to patients 51-84 years old and the elderly. Elderly patients were more likely to undergo an endovascular procedure for tissue loss compared to younger groups. Perioperative and 1-year major amputation rates were highest among patients with premature PAD and decreased with increasing age (P < 0.001), while perioperative and 1-year mortality increased with age (P < 0.001). On multivariable analysis, premature PAD was associated with an increased risk of major amputation (odds ratio, OR = 1.41 [1.22-1.62]), while elderly age was associated with decreased odds of major amputation compared to patients 51-84 years old (OR = 0.61 [0.51-0.73]).

CONCLUSIONS

Patients at the extremes of age have significantly different outcomes after LER for CLTI. Although mortality increases with age, the risk of major amputation decreases. Patients with premature PAD constitute a group of patients with a high risk of perioperative and 1-year major amputation.

The Role of Lower Extremity Amputation in Chronic Limb-Threatening Ischemia

Chronic limb-threatening ischemia (CLTI) is a severe form of peripheral artery disease associated with high rates of limb loss. The primary goal of treatment in CLTI is limb salvage via revascularization. Multidisciplinary teams provide improved care for those with CLTI and lead to improved limb salvage rates. Not all patients are candidates for revascularization, and a subset will require major amputation. This article highlights the role of amputations in the management of CLTI, and describes the patients who should be offered primary amputation.

Literature review and meta-analysis of the efficacy of cilostazol on limb salvage rates after infrainguinal endovascular and open revascularization

BACKGROUND

Current clinical guidelines recommend the use of cilostazol in the treatment of patients with infrainguinal peripheral artery disease (PAD) who experience intermittent claudication. However, the role of cilostazol therapy in patients with advanced PAD and critical limb ischemia (CLI) remains unclear. To conduct a meta-analysis of randomized controlled trials and cohort studies that evaluated the effect of cilostazol vs standard antiplatelet therapy on limb-related and arterial patency-related outcomes. We also reviewed literature pertinent to the effect of cilostazol on wound healing in patients with advanced PAD.

METHODS

We performed a MEDLINE, EMBASE, COCHRANE (CENTRAL), SCOPUS, and US Clinical Trials database search for all trials and studies since 1999 that compared cilostazol with standard antiplatelet therapy in the setting of infrainguinal PAD revascularization procedures (endovascular or open). Aggregate data was collected from four randomized control trials and six retrospective cohort studies. The end point incidence ratios and treatment effects were generated from each study and reported as hazard ratios (HR) using a random-effect model. We also reviewed 10 studies that evaluated the effect of cilostazol on wound healing in patients with advanced PAD.

RESULTS

From more than 25,000 total patients, 3136 patients met our inclusion criteria. All patients had at least lifestyle-impacting intermittent claudication, and more than 50% met the definition of CLI (Rutherford class ≥4). Patient age range was 53 to 83 years, and the majority were male (66%). The mean follow-up time averaged 2 years across all studies. Meta-analysis revealed that cilostazol treatment favored amputation-free survival (hazard ratio [HR], 0.79; 95% confidence interval [CI], 0.69-0.91), limb salvage rate (HR, 0.42; 95% CI, 0.27-0.66), decreased repeat revascularization (risk ratio [RR], 0.44; 95% CI, 0.37-0.52), and decreased restenosis (RR, 0.68; 95% CI, 0.61-0.76). Cilostazol treatment also increased freedom from target lesion revascularization (RR, 1.35; 95% CI, 1.21-1.53) with no difference in all-cause mortality. Effective wound healing was found to be an inconsistent outcome measure in patients receiving cilostazol therapy.

CONCLUSIONS

We observed that cilostazol therapy has a beneficial impact on all limb-related and arterial patency-related outcomes, but no effect on all-cause mortality in patients with advanced PAD and CLI undergoing revascularization procedures. Additional studies are needed to evaluate the effect of cilostazol therapy on wound healing in patients with advanced PAD.

Clinical Outcomes Following Lower Extremity Vein Bypass for Chronic Limb Threatening Ischaemia (CLTI) at the University of Colombo, Sri Lanka

OBJECTIVE

Although high quality epidemiological data are lacking, the global increase in chronic limb threatening ischaemia may be disproportionately affecting low and LMICs. All available data for outcomes from bypass for limb salvage are from high income countries, with none from LMIC settings where the challenge is greatest. This study aimed to assess the clinical outcomes following vein lower extremity bypass for chronic limb threatening ischaemia at the University of Colombo, Sri Lanka, and to compare patients and outcomes with those described in the Society for Vascular Surgery (SVS) Objective Performance Goals (OPG) and United States National Surgical Quality Improvement Program (NSQIP).

METHODS

Consecutive patients (n = 367) undergoing SVS-OPG eligible lower extremity bypass between 2015 and 2017 were studied. Thirty day major adverse cardiovascular events (MACE), major adverse limb events (MALE), deaths, and amputations are reported, along with one year overall survival, limb salvage, and amputation free survival.

RESULTS

Patients at University of Colombo had more diabetes mellitus (80% vs. SVS 57% vs. NSQIP 50%, p < .001) and tissue loss (100% vs. SVS 74% vs. NSQIP 59%, p < .001). The 30 day MALE was 7.6%, which is not a statistically significant difference from the SVS (6.1%) or NSQIP (9%). The 30 day MACE was 8.2%, statistically significantly higher than NSQIP (4.2%, p < .001) but not SVS (6.2%, p = .20). At 12 months, the overall survival (82%) was within the OPG threshold, but limb salvage (81.8%) and amputation free survival (64.5%) were just outside.

CONCLUSION

Outcomes following vein bypass for ischaemic necrosis at the University of Colombo, Sri Lanka, are acceptable and similar to those reported from high income countries despite greater limb threat severity and resource limitations. Further real world data from similar settings on outcomes following revascularisation are required. These data suggest that a vein bypass first strategy for advanced ischaemic necrosis is feasible and effective even in resource limited settings.