Infrapopliteal lesion morphology in patients with critical limb ischemia: implications for the development of anti-restenosis technologies

Short-Term Outcomes of Dual Versus Single Antiplatelet Therapy Following Popliteal and Infrapopliteal Endovascular Therapy: Data From Dutch Chronic Lower Limb-Threatening Ischemia Registry (THRILLER)

OBJECTIVE

There is a lack of consensus regarding the optimal antithrombotic therapy (ATT) after popliteal and infrapopliteal (PIP) endovascular therapy (EVT). Currently, dual antiplatelet therapy (DAPT) for 3 months and single antiplatelet therapy (SAPT) are the most prescribed regimens in the Netherlands. Thus far, no randomized comparison has been performed on the optimal ATT approach. Therefore, this study compared the efficacy and safety of 3-month DAPT with SAPT following PIP EVT.

DESIGN

Retrospective analysis of prospectively collected data from a multicenter registry.

METHODS

The Dutch chronic lower limb-threatening ischemia registry (THRILLER) collected prospective data on patients enrolled between January 2021 and October 2023. As for ATT, only patients prescribed antiplatelet therapy (APT), were included in this analysis. The primary efficacy outcome was a composite of 3-month major adverse cardiovascular events (MACEs, ie, myocardial infarction, cerebrovascular event, cardiovascular death), major adverse limb events (MALEs, ie, major amputation, reintervention), and non-cardiovascular death. Secondary efficacy outcomes were 3-month MACE, MALE, and all-cause mortality. The primary safety outcome was major bleeding according to the 'Thrombolysis In Myocardial Infarction' (TIMI) classification. Descriptive statistics and Cox proportional hazard models were applied.

RESULTS

In total, 460 of 840 THRILLER patients used DAPT or SAPT as ATT and were therefore included in the analysis. Of these, 322 (70%) received DAPT and 138 (30%) received SAPT. In total, 73 (15.9%) primary efficacy outcomes were observed of which 21 (15.2%) events in the SAPT group and 52 (16.1%) events in the DAPT group. No significant differences were observed between SAPT and DAPT for the primary efficacy outcomes or any of the secondary efficacy outcomes. In both groups, one case of major bleeding was observed.

CONCLUSION

The findings suggest that 3 months of DAPT is not superior to SAPT. A well-powered randomized trial is warranted to assess the efficacy and safety of post-procedural DAPT in chronic limb-threatening ischemia (CLTI) patients undergoing PIP EVT.

CLINICAL IMPACT

This manuscript reports on the efficacy and safety outcomes of 3 months of DAPT versus SAPT, which are commonly chosen therapies following popliteal and infrapopliteal endovascular therapy. No significant difference was found between the two groups regarding major adverse cardiovascular events, all-cause death, major amputation, or major bleeding. Therefore, 3 months of DAPT does not seem superior to SAPT. These results suggest that SAPT appears to be a sufficient alternative when considering 3 months of DAPT. Further research should verify these outcomes and focus on the efficacy and safety of prolonged DAPT suppletion after endovascular therapy.

Inter- and Intra-observer Agreement of the Peripheral Arterial Calcium Scoring System in Patients Undergoing (Infra)Popliteal Endovascular Interventions

PURPOSE

Peripheral arterial calcification is an important predictor of outcomes after both conservative and endovascular treatment. Digital subtraction angiography (DSA)-based calcification scores are limited by low sensitivity and inter-observer agreement. The Peripheral Arterial Calcium Scoring System (PACSS) assesses the severity of target lesion calcification. The newly introduced modified PACSS (mPACSS) also evaluates target vessel calcification. This study aimed to assess the inter- and intra-observer reliability of PACSS and mPACSS on computed tomography angiography (CTA) in (infra)popliteal endovascular interventions.

METHODS

A random sample of 50 limbs from the prospective multicenter Dutch Chronic Lower Limb-Threatening Ischemia Registry (THRILLER) were included. Three experienced independent raters scored PACSS on CTA. Three months later, one blinded rater assessed the same 50 CTA scans, keeping track of assessment time. The reliability of the original 5-step PACSS, a simplified binary PACSS (0-2 vs 3-4) and the 7-step mPACSS were tested using Cohen's and Fleiss' kappa statistics.

RESULTS

In total, 50 limbs (mean age 70.1 ± 11.0, 29 men) with 41 popliteal and 40 infrapopliteal lesions were scored. Inter-observer agreement of PACSS and binary PACSS were moderate (κ = 0.60) and substantial (κ = 0.72), respectively, while intra-observer agreement was almost perfect in both scores (κ = 0.86). Inter- and intra-observer agreement of mPACSS were moderate (κ = 0.48) and substantial (κ = 0.77), respectively. Mean assessment time for an experienced rater was 3.43 ± 0.93 min per CTA scan.

CONCLUSION

Both the semi-quantitative PACSS and mPACSS scores for (infra)popliteal arteries can be performed reliably on pre-operative CTA.

Vessel Preparation in Infrapopliteal Arterial Disease: A Systematic Review and Meta-Analysis

PURPOSE

Infrapopliteal lesions are generally complex to treat due to small vessel diameter, long lesion length, multilevel disease, and severe calcification. Therefore, different vessel preparation devices have been developed to contribute to better peri- and postprocedural outcomes. This systematic review aims to compare different vessel preparation techniques prior to plain old balloon angioplasty (POBA) or drug-coated balloon (DCB) angioplasty with POBA or DCB alone in infrapopliteal arterial disease.

METHODS

Medline, EMBASE, and Cochrane databases were searched for studies published between 2000 and 2022 assessing the value of adjunctive vessel preparation in infrapopliteal arterial disease. The primary outcomes were 12-month primary patency and limb salvage.

RESULTS

A total of 1685 patients with 1913 lesions were included in 11 POBA studies. Methodological quality was assessed as poor to moderate in these studies. Only 2 studies with 144 patients assessed vessel preparation in conjunction with DCB angioplasty. These randomized trials were assessed as high quality and found no significant benefit of adjunctive atherectomy to DCB angioplasty. The pooled Kaplan-Meier estimates of 12-month primary patency and limb salvage in the POBA studies were 67.8% and 80.9% for POBA, 62.1% and 86.4% for scoring balloons, 67.9% and 79.6% for mechanical atherectomy (MA), and 79.7% and 82.6% for laser atherectomy, respectively. Within the pooled data only scoring balloons and MA demonstrated significantly improved 12-month limb salvage compared to POBA.

CONCLUSIONS

Different forms of adjunctive vessel preparation demonstrate similar 12-month outcomes compared to POBA and DCB angioplasty alone in infrapopliteal disease, with the exception of improved 12-month limb salvage in scoring balloons and MA. However, since the included studies were heterogeneous and assessed as poor to moderate methodological quality, selection bias may have played an important role. Main conclusion is that this systematic review found no additional value of standard use of vessel preparation.

CLINICAL IMPACT

Infrapopliteal arterial disease is associated with chronic limb-threatening ischemia (CLTI) and generally complex to treat due to small vessel diameter, long lesion length, multilevel disease and severe calcification. A wide range of vessel preparation devices have been developed to contribute to improved peri- and postprocedural outcomes in these complex lesions. This systematic review aims to compare different vessel preparation techniques prior to plain old balloon angioplasty (POBA) or drug coated balloon (DCB) angioplasty with POBA or DCB angioplasty alone in infrapopliteal arterial disease. Different forms of adjunctive vessel preparation demonstrate similar 12-month outcomes compared to POBA and DCB angioplasty alone in infrapopliteal disease, with the exception of improved 12-month limb salvage in scoring balloons and mechanical atherectomy (MA). However, since the included studies were heterogeneous and assessed as poor to moderate methodological quality, selection bias may have played an important role. Main conclusion is that this systematic review found no additional value of standard use of vessel preparation.

The Dutch chronic lower limb-threatening ischemia registry (THRILLER): A study protocol for popliteal and infrapopliteal endovascular interventions

INTRODUCTION

Chronic limb-threatening ischemia (CLTI) is the end stage of peripheral arterial disease (PAD) and is associated with high amputation rates, mortality and disease-related health care costs. In infrapopliteal arterial disease (IPAD), endovascular revascularization should be considered for the majority of anatomical and clinical subgroups of CLTI. However, a gap of high-quality evidence exists in this field. The aim of the Dutch Chronic Lower Limb-Threatening Ischemia Registry (THRILLER) is to collect real world data on popliteal and infrapopliteal endovascular interventions.

METHODS

THRILLER is a clinician-driven, prospective, multicenter, observational registry including all consecutive patients that undergo a popliteal or infrapopliteal endovascular intervention in seven Dutch hospitals. We estimate that THRILLER will include 400-500 interventions annually. Standardized follow-up visits with wound monitoring, toe pressure measurement and duplex ultrasonography will be scheduled at 6-8 weeks and 12 months after the intervention. The independent primary endpoints are primary patency, limb salvage and amputation free survival. Patients must give informed consent before participation and will be included according to predefined reporting standards. A data log of patients who meet the inclusion criteria but are not included in the registry will be maintained. We intend to conduct the first interim analysis two years after the start of inclusion. The results will be published in a scientific journal.

DISCUSSION

Despite innovations in medical therapy and revascularization techniques, patients with CLTI undergoing endovascular revascularization still have a moderate prognosis. Previous prospective cohort studies were hampered by small sample sizes or heterogeneous reporting. Randomized controlled trials (RCTs) have high costs, potential conflicts of interest and give a limited reflection of daily practice. THRILLER aims to provide the largest prospective well phenotyped up-to-date dataset on treatment outcomes in CLTI patients to answer multiple underexplored research questions regarding diagnostics, medication, patient selection, treatment strategies and post intervention follow-up.

Paclitaxel-coated balloons versus percutaneous transluminal angioplasty for infrapopliteal chronic total occlusions: the IN.PACT BTK randomised trial

BACKGROUND

Data are mixed concerning the safety and effectiveness of drug-coated balloons (DCBs) for treating below-the-knee (BTK) lesions.

AIMS

The aim of this study was to assess the safety and effectiveness of the IN.PACT 014 paclitaxel-coated balloon catheter versus conventional percutaneous transluminal angioplasty (PTA) for infrapopliteal chronic total occlusions (CTOs) in patients with chronic limb-threatening ischaemia (CLTI).

METHODS

The IN.PACT BTK randomised study is a prospective, multicentre, randomised pilot study. Fifty CLTI participants (Rutherford clinical category 4-5) with BTK CTOs were randomised 1:1 to DCB (N=23) or PTA (N=27). The primary effectiveness endpoint was late lumen loss (LLL) at 9 months post procedure. Safety outcomes up to 9 months included all-cause mortality, major target limb amputation, and clinically driven target lesion revascularisation (CD-TLR).

RESULTS

Mean lesion length was 215.41±83.81 mm in the DCB group and 218.19±80.43 mm for PTA (p=0.806). The 9-month angiographic LLL was 0.892±0.774 mm for the DCB group and 1.312±0.720 mm for the PTA group (p=0.070) in a classic analysis, and 0.592±0.944 mm for DCB and 1.260±0.810 mm for PTA (p=0.017) in a subsegmental analysis. The Kaplan-Meier estimated freedom from CD-TLR up to 9 months was 91.1% for DCB and 91.8% for PTA (log-rank p=0.942). At 9 months, 1 patient died in the DCB group and 2 in the PTA group (p=1.000); there were no major target limb amputations in either arm.

CONCLUSIONS

The 9-month subsegmental LLL was lower after treatment with the IN.PACT 014 DCB compared with PTA with no differences in safety or revascularisation events in a small complex population of patients with BTK CTOs.

CLINICALTRIALS

gov: NCT02963649.

[Primary retrograde distal access for endovascular interventions in patients with lower limb ischemia]

OBJECTIVE

To evaluate safety and technical efficiency of primary retrograde distal access for endovascular interventions in patients with lower limb ischemia.

MATERIAL AND METHODS

A prospective analysis included 25 endovascular procedures via primary retrograde distal access in 23 patients with chronic obliterating diseases of lower limb arteries. Occlusive lesion of femoral-popliteal segment was observed in 68% of cases, occlusion of at least one tibial artery was also found in 68% of cases. In 44% of cases, occlusive lesion was localized at several levels. Percutaneous intervention via anterior tibial artery or dorsalis pedis artery was performed in 68% of cases, posterior tibial artery - 24% of cases, peroneal artery - 8% of cases. We used 2 accesses in 92% of cases (the main one for intervention and additional one for angiography). In 8% of cases, intervention was carried out through a single access. Angiosome artery was punctured in 65% of cases. The only patent tibial vessel was used in 20% of cases. In 24% of cases, we performed antegrade recanalization of 'adjacent' tibial artery via distal access.

RESULTS

Primary retrograde distal access was successfully performed in 100% of cases. Retrograde revascularization was not successful in all cases (successful recanalization rate 96%, retrograde intervention rate - 92%). Femoral access was performed in 8% of cases. Antegrade blood flow through at least one tibial artery was restored in all cases. Direct revascularization of the affected angiosome was performed in 15 patients with foot necrosis, indirect revascularization through collaterals - in 5 patients. Local complications of surgical access occurred in 12% of cases.

CONCLUSION

Endovascular revascularization via primary retrograde distal access was technically effective in most cases. There were no complications with systemic consequences.

Balloon Angioplasty of Infrapopliteal Arteries: A Systematic Review and Proposed Algorithm for Optimal Endovascular Therapy

Endovascular revascularization has been increasingly utilized to treat patients with chronic limb-threatening ischemia (CLTI), particularly atherosclerotic disease in the infrapopliteal arteries. Lesions of the infrapopliteal arteries are the result of 2 different etiologies: medial calcification and intimal atheromatous plaque. Although several devices are available for endovascular treatment of infrapopliteal lesions, balloon angioplasty still comprises the mainstay of therapy due to a lack of purpose-built devices. The mechanism of balloon angioplasty consists of adventitial stretching, medial necrosis, and dissection or plaque fracture. In many cases, the diffuse nature of infrapopliteal disease and plaque complexity may lead to dissection, recoil, and early restenosis. Optimal balloon angioplasty requires careful attention to assessment of vessel calcification, appropriate vessel sizing, and the use of long balloons with prolonged inflation times, as outlined in a treatment algorithm based on this systematic review. Further development of specific devices for this arterial segment are warranted, including devices for preventing recoil (eg, dedicated atherectomy devices), treating dissections (eg, tacks, stents), and preventing neointimal hyperplasia (eg, novel drug delivery techniques and drug-eluting stents). Further understanding of infrapopliteal disease, along with the development of new technologies, will help optimize the durability of endovascular interventions and ultimately improve the limb-related outcomes of patients with CLTI.

Global Vascular Guidelines on the Management of Chronic Limb-Threatening Ischemia

GUIDELINE SUMMARY

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Antiplatelet therapy for tibial balloon angioplasty: A clinical perspective

Percutaneous transluminal tibial balloon angioplasty has an important role in the therapeutic approach of critical limb ischaemia. Despite a growing number of patients with critical limb ischaemia, there are no trials to guide the pharmacologic approach post intervention. Guidelines pertaining to the antiplatelet therapy post percutaneous transluminal tibial balloon angioplasty have not been developed. In addition, critical limb ischaemia patients have multiple comorbidities and a higher risk of bleeding. To examine the shortest duration of antiplatelet therapy post percutaneous transluminal tibial balloon angioplasty, we reviewed the preclinical data used to develop the standards for the current angioplasty technique.

Global vascular guidelines on the management of chronic limb-threatening ischemia

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Early Recoil After Balloon Angioplasty of Erection-Related Arteries in Patients With Arteriogenic Erectile Dysfunction

Purpose: To evaluate the incidence of elastic recoil in patients presenting with erectile dysfunction (ED) undergoing endovascular revascularization of the pudendal or penile arteries. Methods: A consecutive series of 21 ED patients (mean age 58.3±9.3 years) undergoing minimally invasive revascularization of 31 arteries was analyzed. ED lesions included the pudendal arteries (n=27) and the penile artery (n=4). Mean lesion length was 20.6±13.9 mm. Minimal lumen diameter (MLD) measurements were assessed at baseline, immediately after balloon angioplasty, and 10 minutes thereafter. Early recoil was defined as an MLD reduction >10%. Elastic recoil with >10% lumen compromise was treated with drug-coated balloons, while severe elastic recoil (>30%) required drug-eluting stents (DES). The International Index of Erectile Function (IIEF-15) score was obtained prior to and 3 months after the procedure to obtain information on functional outcomes subsequent to angioplasty. Results: Mean MLD at baseline was 0.9±0.6 mm, which improved to 2.0±0.9 mm immediately after balloon dilation. At 10 minutes after dilation, the MLD was 1.7±1.0 mm. Elastic recoil was observed in all 31 lesions and resulted in a mean lumen compromise of 21.2%. Severe (>30%) recoil was observed in 14 arteries, which underwent DES therapy. The IIEF-15 score improved from 31.3±11.2 at baseline to 49.8±16.8 (p<0.001) at the 3-month follow-up. Conclusion: Endovascular revascularization constitutes a safe and feasible treatment modality to restore erectile function in patients with arteriogenic ED and ineffective conservative management. Early elastic recoil is very frequent subsequent to balloon dilation of small-caliber erection-related arteries. Thus, mechanical scaffolding with DES is required in a high subset of ED patients to provide favorable early angiographic and clinical results.

Pilot Cohort Study Assessing the Efficacy of Endovascular Revascularization in the Restoration of Peripheral Sensory Disturbance in Patients With Critical Limb Ischemia

BACKGROUND

Sensory disturbance (SD) is a common consequence of peripheral nerve damage associated with diabetes and severe ischemia. Progression of SD places patients at high risk for lower extremity ulcers and amputations. SD has been thought to be progressive and irreversible, and possibly caused by microvascular dysfunction. The aim of this study was to determine whether endovascular revascularization (EVR) induces quantifiable changes in SD in chronic critical limb ischemia (CLI) patients with neuropathy.

METHODS AND RESULTS

In all, 36 legs from 28 chronic CLI patients who underwent elective EVR were prospectively enrolled in this study (64% with diabetes and 54% on maintenance hemodialysis). The current perception threshold (CPT), an established diagnostic parameter for SD, was measured before and 3 months after EVR. Of the target lesions, 11%, 47%, and 81% were in the aortoiliac, femoropopliteal, and below-the-knee arteries, respectively, and 58% were totally occluded. Overall CPT in the target foot had improved significantly 3 months after EVR (from 53 to 30 µA; P=0.010); however, EVR did not change CPT in the non-target foot (from 44 to 33 µA; P=0.33). Patients with improved SD after EVR had a significantly higher 180-day survival rate (94% vs. 63%; P=0.040).

CONCLUSIONS

EVR improved CPT in target limbs of patients with CLI, and may be a promising option to improve SD associated with peripheral ischemic sensory neuropathy.

Midterm Outcomes After Infrapopliteal Interventions in Patients With Critical Limb Ischemia Based on the TASC II Classification of Below-the-Knee Arteries

Purpose: To analyze the relationship between the new TransAtlantic Inter-Society Consensus (TASC II) infrapopliteal classification and limb outcomes among patients with critical limb ischemia (CLI). Methods: A single-center retrospective study was performed on 166 consecutive CLI patients (mean age 71 years; 113 men) undergoing endovascular treatment of 244 infrapopliteal lesions from 2006 to 2013. Patient, procedural, angiographic, and limb outcomes were compared for the new TASC A/B vs C/D classification for infrapopliteal lesions. Binary restenosis was determined by a peak systolic velocity ratio >2.0 by duplex ultrasound on follow-up at 1, 3, 6, and 12 months. Results: Seventy-two (43.4%) patients had TASC A/B lesions, while 94 (56.6%) had TASC C/D patterns of infrapopliteal disease. Baseline demographics and tissue loss (93% vs 94%, p=0.59) were similar between the groups. TASC A/B lesions were shorter (53±35 vs 170±83 mm, p<0.001), less severely stenosed (77%±24% vs 93%±14%, p<0.001), had a larger target vessel diameter (2.9±0.5 vs 2.6±0.5 mm, p<0.001), and were less frequently chronic total occlusions (24% vs 64%, p<0.001) compared with the TASC C/D group. Three-year freedom from both amputation (85% vs 67%, p=0.02) and major adverse limb events (79% vs 61%, p=0.02) were significantly higher in the TASC A/B group. Technical success rates (95% vs 80%, p<0.001) and 1-year primary patency (58% vs 51%, p=0.04) were higher in the A/B group. Overall 3-year survival was similar between the groups (96% A/B vs 88% C/D, p=0.2). Conclusion: TASC C/D infrapopliteal lesions are associated with higher amputation and major adverse limb events rates and lower primary patency compared with TASC A/B infrapopliteal lesions. Further studies are needed to assess the association between TASC C/D infrapopliteal lesions and clinical outcomes in patients with CLI.

Predictors for Better Blood-Flow Restoration of Long-Segmental Below-the-Knee Chronic Total Occlusions after Endovascular Therapy in Diabetic Patients

OBJECTIVE

To prospectively investigate predictors for good restoration of blood flow of below-the-knee (BTK) chronic total occlusions (CTOs) after endovascular therapy in diabetes mellitus (DM) patients.

MATERIALS AND METHODS

A total of 120 long-segmental (≥ 5 cm) BTK, CTOs in 81 patients who underwent recanalization were included in this study. After angioplasty, blood-flow restoration was assessed using modified thrombolysis in myocardial ischemia grades and classified as good flow (grade 3) and poor flow (grade 1/2). One hundred and six CTOs with successful recanalization were divided into a good flow group (GFG; n = 68) and poor flow group (PFG; n = 38). Multivariate logistic regression analyses were undertaken to determine independent predictors of blood-flow restoration. Receiver operating characteristic curves were constructed to determine the best cutoff value. The prevalence of target-lesion restenosis during follow-up was compared between two groups.

RESULTS

Univariate analyses suggested that CTOs in GFG were characterized by lighter limb ischemia (p = 0.03), shorter course of ischemic symptoms (p < 0.01) and lesion length (p = 0.04), more frequent use of intraluminal angioplasty (p = 0.03), and higher runoff score (p < 0.01) than those in PFG. Multivariate regression analyses suggested that distal runoffs (p = 0.001; odds ratio [OR], 10.32; 95% confidence interval [CI]: 4.082-26.071) and lesion length (p < 0.001; OR, 1.26; 95% CI: 1.091-1.449) were independent predictors for good flow restoration. Kaplan-Meier analyses at 12 months showed a higher prevalence of non-restenosis in GFG (p < 0.01).

CONCLUSION

Distal runoffs and lesion length are independent predictors for good flow restoration for long-segmental BTK, CTOs in DM patients who receive endovascular therapy.

Runoff Detected by Magnetic Resonance Angiography as an Indicator for Better Recanalization Outcomes in Below-the-Knee Chronic Total Occlusions in Diabetic Patients

Purpose: To compare the feasibility and efficacy of recanalizing below-the-knee (BTK) chronic total occlusions (CTOs) between patients with good or poor distal runoff based on magnetic resonance angiography (MRA) scans. Methods: Two hundred long-segment BTK CTOs in 171 limbs of 113 diabetic patients (58 men; mean age 69.8±1.9 years) were divided into good distal runoff (GDR: 119 lesions, 98 limbs) or poor distal runoff groups (PDR: 81 lesions, 73 limbs) based on baseline MRA findings. After angioplasty, modified thrombolysis in myocardial ischemia (mTIMI) grades and ankle-brachial index (ABI) were used to assess immediate outcomes. Regularly scheduled duplex or MRA imaging was performed in follow-up. The restenosis and limb salvage rates were compared. Results: The success rates were 93.3% and 87.7% in the GDR and PDR groups, respectively (p=0.21); subintimal angioplasty was more common in the PDR group (93.0% vs. 63.1%, p<0.01). Completion angiography indicated an mTIMI grade 3 blood flow in 71.2% lesions in the GDR patients and in 52.1% in the PDR (p=0.01) group. Improvement in the ABI was greater in the GDR limbs (p<0.001 vs. PDR). Mean imaging follow-up was 10.8±6.9 months in the GDR group and 11.1±6.6 months in the PDR group. Kaplan-Meier analysis showed a better restenosis-free rate in the GDR group (80.6% vs. 61.7%; p=0.02) at 12 months and for lesions with mTIMI grade 3 flow (p<0.01). At 24 months, Kaplan-Meier analysis revealed a better limb salvage rate in the GDR group (84.2% vs. 54.6%; p=0.02). Conclusion: Distal runoff detected using MRA could be a predictor for successful intraluminal recanalization, better distal tissue perfusion, improved long-term patency, and better limb salvage for patients with BTK CTOs.

The Importance of Patency in Patients with Critical Limb Ischemia Undergoing Endovascular Revascularization for Infrapopliteal Arterial Disease

Critical limb ischemia (CLI) represents the most severe form of peripheral arterial disease (PAD) and frequently occurs in medically frail patients. CLI patients frequently exhibit multi-segmental PAD commonly including the tibial arterial segment. Endovascular therapy has been established as first-line revascularization strategy for most CLI patients. Restenosis was reported to occur in up to more than two-thirds of CLI patients undergoing angioplasty of complex tibial arterial obstructions. Nevertheless, favorable clinical outcomes were observed for infrapopliteal angioplasty when compared with bypass surgery, despite higher patency rates for the latter. Based on these observations, infrapopliteal patency was considered to be only of secondary importance upon clinical outcomes in CLI patients. In contrast to these earlier observations, however, recent findings from two randomized clinical trials indicate that infrapopliteal patency does impact on clinical outcomes in CLI patients. The purpose of the present manuscript is to provide a critical reappraisal of the present literature on the clinical importance of tibial arterial patency in CLI patients undergoing endovascular revascularization and to discuss utility and limitations of currently available anti-restenosis technologies.

Contemporary crossing techniques for infrapopliteal chronic total occlusions

The synergism of technical refinement and advanced technology has significantly increased the popularity of infrapopliteal intervention. Since chronic total occlusion (CTO) is a common disorder among patients with symptomatic infrapopliteal artery disease, infrapopliteal CTO intervention is now evolving rapidly in the field of endovascular intervention. Guidewire crossing through the CTO is essential for a successful procedure. We review up-to-date infrapopliteal CTO crossing techniques based on the current literature.

Does patency matter in patients with critical limb ischemia undergoing endovascular revascularization?

Restenosis is the major drawback in patients undergoing tibial angioplasty. In contrast to earlier observations, tibial patency was shown to impact on clinical outcomes in current randomized trials and is thus attributed more importance. Accordingly, intentions to reduce tibial restenosis have been intensified. Both drug-eluting balloons (DEB) and drug-eluting stents (DES) were shown to reduce tibial restenosis when compared with its plain counterparts. However, both endovascular technologies have its limitations for tibial arterial application. While DEB technology may not address elastic recoil, a pathophysiological mechanism frequently observed in tibial arteries and a significant contributor to restenosis, currently available DES do not fully address tibial arterial lesion morphology. Purpose of the present manuscript is to outline the problem and the incidence of tibial arterial restenosis, its importance on clinical outcomes and to provide an overview on technical developments aimed at its prevention.